pptx_edit/

deck.rs

use std::collections::{BTreeMap, HashMap, HashSet};
use std::sync::Arc;

use ooxml_drawingml::{
    ColorValue, ShapeFill, ShapeOutline, Theme, preset_geometry_default_adjustments,
    preset_geometry_to_path, resolve_color_value_to_hex, resolve_color_value_to_hex_with_theme,
};
use pptx_parse::{ChartAxis, ChartSpace, PptxPackage, ShapeBase, ShapeNode, Slide};
use serde::de::DeserializeOwned;
use yrs::{
    Any, Array, ArrayPrelim, ArrayRef, Doc, Map, MapPrelim, MapRef, Out, ReadTxn, TextRef,
    Transact, TransactionMut, WriteTxn,
};

use crate::comments::{flavor_key, seed_comments, snapshot_comments, snapshot_flavor};
use crate::story::{seed_plain_story, seed_story, snapshot_story, validate_story};
use crate::{
    DeckSession, DeckSnapshot, EditCtx, EditError, EditResult, META, MIGRATE_ORIGIN,
    PresetShapeDraft, SHAPES, SLIDE_ORDER, SLIDES, STORIES, ShapeAdjustReceipt, ShapeDraft,
    ShapeFillReceipt, ShapeKind, ShapeReceipt, ShapeRect, ShapeSnapshot, ShapeStroke,
    ShapeStrokeReceipt, SlideReceipt, SlideSnapshot, TransformReceipt,
};

const SCHEMA_VERSION: f64 = 2.1;
/// Versions [`migrate_doc`] can carry forward. Anything else is unreadable.
const MIGRATABLE_SCHEMA_VERSIONS: [f64; 3] = [1.0, 2.0, SCHEMA_VERSION];
const MAX_GEOMETRY: i64 = 1_000_000_000_000_000;
const MAX_SHAPE_DEPTH: usize = 128;
const EMU_PER_POINT: f64 = 12_700.0;
const MAX_ADJUSTMENTS: usize = 32;
const MAX_ADJUSTMENT_INDEX: usize = 32;

pub(crate) fn seed_doc(doc: &Doc, package: &PptxPackage, fingerprint: &str) -> EditResult<()> {
    let package_json =
        serde_json::to_vec(package).map_err(|error| EditError::Json(error.to_string()))?;
    let mut txn = doc.transact_mut_with("pptx:bootstrap");
    let meta = txn.get_or_insert_map(META);
    meta.insert(&mut txn, "schemaVersion", SCHEMA_VERSION);
    meta.insert(&mut txn, "fingerprint", fingerprint);
    meta.insert(&mut txn, "widthEmu", package.presentation.width_emu as f64);
    meta.insert(
        &mut txn,
        "heightEmu",
        package.presentation.height_emu as f64,
    );
    meta.insert(
        &mut txn,
        "packageJson",
        Any::Buffer(Arc::from(package_json)),
    );
    meta.insert(
        &mut txn,
        "commentFlavor",
        flavor_key(package.comment_flavor.unwrap_or_default()),
    );
    let order = txn.get_or_insert_array(SLIDE_ORDER);
    let slides = txn.get_or_insert_map(SLIDES);
    let shapes = txn.get_or_insert_map(SHAPES);
    let stories = txn.get_or_insert_map(STORIES);
    let mut slide_id_by_part: HashMap<String, String> = HashMap::new();

    for (slide_index, slide) in package.slides.iter().enumerate() {
        let theme = slide_theme(package, slide);
        let slide_id = seeded_slide_id(slide_index, package.presentation.slides[slide_index].id);
        order.push_back(&mut txn, slide_id.as_str());
        let slide_map = slides.insert(&mut txn, slide_id.as_str(), MapPrelim::default());
        slide_map.insert(&mut txn, "id", slide_id.as_str());
        slide_map.insert(&mut txn, "sourcePartPath", slide.part_path.as_str());
        if let Some(layout) = &slide.layout_part_path {
            slide_map.insert(&mut txn, "layoutPartPath", layout.as_str());
        }
        if let Some(name) = &slide.name {
            slide_map.insert(&mut txn, "name", name.as_str());
        }
        if !slide.notes.is_empty() {
            slide_map.insert(&mut txn, "notes", slide.notes.as_str());
        }
        let shape_order = slide_map.insert(&mut txn, "shapes", ArrayPrelim::default());
        for (shape_index, shape) in slide.shapes.iter().enumerate() {
            let shape_id = seed_shape(
                &shapes,
                &stories,
                &mut txn,
                &slide_id,
                &shape_index.to_string(),
                shape,
                theme,
            )?;
            shape_order.push_back(&mut txn, shape_id.as_str());
        }
        slide_id_by_part.insert(slide.part_path.clone(), slide_id);
    }
    seed_comments(&mut txn, package, &|part| {
        slide_id_by_part.get(part).cloned()
    })?;
    Ok(())
}

fn seed_shape(
    shapes: &MapRef,
    stories: &MapRef,
    txn: &mut TransactionMut<'_>,
    slide_id: &str,
    path: &str,
    shape: &ShapeNode,
    theme: Option<&Theme>,
) -> EditResult<String> {
    let shape_id = seeded_shape_id(slide_id, path);
    let shape_map = shapes.insert(txn, shape_id.as_str(), MapPrelim::default());
    let base = shape_base(shape);
    shape_map.insert(txn, "id", shape_id.as_str());
    shape_map.insert(txn, "sourceId", base.id as f64);
    shape_map.insert(txn, "name", base.name.as_str());
    shape_map.insert(txn, "x", base.transform.x as f64);
    shape_map.insert(txn, "y", base.transform.y as f64);
    shape_map.insert(txn, "width", base.transform.width as f64);
    shape_map.insert(txn, "height", base.transform.height as f64);
    shape_map.insert(txn, "rotationDeg", base.transform.rotation_deg);
    shape_map.insert(txn, "flipH", base.transform.flip_h);
    shape_map.insert(txn, "flipV", base.transform.flip_v);
    if base.hidden {
        shape_map.insert(txn, "hidden", true);
    }
    insert_json(
        &shape_map,
        txn,
        "placeholderJson",
        base.placeholder.as_ref(),
    )?;

    let mut text_story_ids = Vec::new();
    let mut child_ids = Vec::new();
    match shape {
        ShapeNode::Shape(shape) => {
            shape_map.insert(txn, "kind", "shape");
            shape_map.insert(txn, "geometry", shape.geometry.as_str());
            if !shape.has_preset_geometry {
                shape_map.insert(txn, "hasPresetGeometry", false);
            }
            let mut adjust_values = preset_geometry_default_adjustments(&shape.geometry)
                .into_iter()
                .collect::<BTreeMap<_, _>>();
            adjust_values.extend(shape.adjust_values.clone());
            insert_json(&shape_map, txn, "adjustValuesJson", Some(&adjust_values))?;
            insert_json(&shape_map, txn, "fillJson", shape.fill.as_ref())?;
            insert_json(&shape_map, txn, "outlineJson", shape.outline.as_ref())?;
            if let Some(body) = &shape.text {
                let story_id = format!("story:{shape_id}:0");
                seed_story(stories, txn, &story_id, body, theme)?;
                text_story_ids.push(story_id);
            }
        }
        ShapeNode::Picture(picture) => {
            shape_map.insert(txn, "kind", "picture");
            shape_map.insert(txn, "geometry", "rect");
            insert_json(&shape_map, txn, "fillJson", picture.fill.as_ref())?;
            insert_json(&shape_map, txn, "outlineJson", picture.outline.as_ref())?;
            if !picture.effects.is_empty() {
                insert_json(&shape_map, txn, "blipEffectsJson", Some(&picture.effects))?;
            }
            if let Some(media) = &picture.media_part_path {
                shape_map.insert(txn, "mediaPartPath", media.as_str());
            }
        }
        ShapeNode::GraphicFrame(frame) => {
            shape_map.insert(txn, "kind", "graphicFrame");
            shape_map.insert(txn, "geometry", "rect");
            insert_json(&shape_map, txn, "graphicJson", Some(&frame.data))?;
            if let pptx_parse::GraphicFrameData::Table(table) = &frame.data {
                for (row_index, row) in table.rows.iter().enumerate() {
                    for (cell_index, cell) in row.cells.iter().enumerate() {
                        let story_id = format!("story:{shape_id}:table:{row_index}:{cell_index}");
                        seed_story(stories, txn, &story_id, &cell.text, theme)?;
                        text_story_ids.push(story_id);
                    }
                }
            }
        }
        ShapeNode::Group(group) => {
            shape_map.insert(txn, "kind", "group");
            shape_map.insert(txn, "geometry", "group");
            for (child_index, child) in group.children.iter().enumerate() {
                child_ids.push(seed_shape(
                    shapes,
                    stories,
                    txn,
                    slide_id,
                    &seeded_child_path(path, child_index),
                    child,
                    theme,
                )?);
            }
        }
    }
    shape_map.insert(txn, "textStories", string_array(&text_story_ids));
    shape_map.insert(txn, "children", string_array(&child_ids));
    Ok(shape_id)
}

fn seeded_slide_id(slide_index: usize, reference_id: u32) -> String {
    format!("slide:{slide_index}:{reference_id}")
}

fn seeded_shape_id(slide_id: &str, path: &str) -> String {
    format!("{slide_id}:shape:{path}")
}

fn seeded_child_path(path: &str, child_index: usize) -> String {
    format!("{path}.{child_index}")
}

pub(crate) fn shape_base(shape: &ShapeNode) -> &ShapeBase {
    match shape {
        ShapeNode::Shape(shape) => &shape.base,
        ShapeNode::Picture(shape) => &shape.base,
        ShapeNode::GraphicFrame(shape) => &shape.base,
        ShapeNode::Group(shape) => &shape.base,
    }
}

fn slide_theme<'a>(package: &'a PptxPackage, slide: &Slide) -> Option<&'a Theme> {
    theme_for_layout(package, slide.layout_part_path.as_deref())
}

fn theme_for_layout<'a>(
    package: &'a PptxPackage,
    layout_part_path: Option<&str>,
) -> Option<&'a Theme> {
    let layout = layout_part_path
        .and_then(|path| {
            package
                .layouts
                .iter()
                .find(|layout| layout.part_path == path)
        })
        .or_else(|| package.layouts.first());
    let master = layout
        .and_then(|layout| layout.master_part_path.as_deref())
        .and_then(|path| {
            package
                .masters
                .iter()
                .find(|master| master.part_path == path)
        })
        .or_else(|| {
            layout.and_then(|layout| {
                package.masters.iter().find(|master| {
                    master
                        .layout_part_paths
                        .iter()
                        .any(|path| path == &layout.part_path)
                })
            })
        })
        .or_else(|| package.masters.first());
    master
        .and_then(|master| master.theme_part_path.as_deref())
        .and_then(|path| package.themes.iter().find(|theme| theme.part_path == path))
        .map(|part| &part.theme)
        .or_else(|| package.themes.first().map(|part| &part.theme))
}

fn insert_json<T: serde::Serialize>(
    map: &MapRef,
    txn: &mut TransactionMut<'_>,
    key: &str,
    value: Option<&T>,
) -> EditResult<()> {
    if let Some(value) = value {
        let json =
            serde_json::to_string(value).map_err(|error| EditError::Json(error.to_string()))?;
        map.insert(txn, key, json);
    }
    Ok(())
}

impl DeckSession {
    pub fn snapshot(&self) -> EditResult<DeckSnapshot> {
        snapshot_doc(&self.doc, &self.package)
    }

    pub fn insert_slide(
        &self,
        context: &EditCtx,
        index: u32,
        layout_part_path: Option<&str>,
    ) -> EditResult<SlideReceipt> {
        if let Some(path) = layout_part_path
            && !self
                .package
                .layouts
                .iter()
                .any(|layout| layout.part_path == path)
        {
            return Err(EditError::InvalidState(format!(
                "unknown slide layout {path:?}"
            )));
        }
        let slide_id = self.next_id("slide");
        let mut txn = self.transact_for(context);
        let order = required_order(&txn)?;
        let length = order.len(&txn);
        if index > length {
            return Err(EditError::OutOfBounds { index, length });
        }
        let slides = required_map(&txn, SLIDES)?;
        let slide = slides.insert(&mut txn, slide_id.as_str(), MapPrelim::default());
        slide.insert(&mut txn, "id", slide_id.as_str());
        slide.insert(&mut txn, "name", format!("Slide {}", length + 1));
        if let Some(layout_part_path) = layout_part_path {
            slide.insert(&mut txn, "layoutPartPath", layout_part_path);
        }
        slide.insert(&mut txn, "shapes", ArrayPrelim::default());
        order.insert(&mut txn, index, slide_id.as_str());
        Ok(SlideReceipt {
            slide_id,
            from_index: None,
            to_index: Some(index),
        })
    }

    pub fn set_slide_notes(&self, context: &EditCtx, slide_id: &str, text: &str) -> EditResult<()> {
        crate::model::validate_xml_text(text)?;
        self.add_undo_barrier();
        let mut txn = self.transact_for(context);
        let slide = slide_ref(&txn, slide_id)?;
        slide.insert(&mut txn, "notes", text);
        drop(txn);
        self.add_undo_barrier();
        Ok(())
    }

    pub fn delete_slide(&self, context: &EditCtx, slide_id: &str) -> EditResult<SlideReceipt> {
        let mut txn = self.transact_for(context);
        let order = required_order(&txn)?;
        let index = array_index(&order, &txn, slide_id)
            .ok_or_else(|| EditError::SlideNotFound(slide_id.to_owned()))?;
        let slides = required_map(&txn, SLIDES)?;
        let slide = slide_ref(&txn, slide_id)?;
        let shape_order = slide_shape_order(&slide, &txn)?;
        let shape_ids = string_array_ref(&shape_order, &txn);
        remove_shape_entries(&mut txn, &shape_ids)?;
        let comments = required_map(&txn, crate::COMMENTS)?;
        let comment_ids: Vec<String> = comments
            .iter(&txn)
            .filter_map(|(id, value)| {
                let entry = value.cast::<MapRef>().ok()?;
                (map_string(&entry, &txn, "slideId").as_deref() == Some(slide_id))
                    .then(|| id.to_owned())
            })
            .collect();
        for id in comment_ids {
            comments.remove(&mut txn, &id);
        }
        order.remove(&mut txn, index);
        slides.remove(&mut txn, slide_id);
        Ok(SlideReceipt {
            slide_id: slide_id.to_owned(),
            from_index: Some(index),
            to_index: None,
        })
    }

    pub fn move_slide(
        &self,
        context: &EditCtx,
        slide_id: &str,
        to_index: u32,
    ) -> EditResult<SlideReceipt> {
        let mut txn = self.transact_for(context);
        let order = required_order(&txn)?;
        let length = order.len(&txn);
        if to_index >= length {
            return Err(EditError::OutOfBounds {
                index: to_index,
                length,
            });
        }
        let from_index = array_index(&order, &txn, slide_id)
            .ok_or_else(|| EditError::SlideNotFound(slide_id.to_owned()))?;
        if from_index != to_index {
            order.remove(&mut txn, from_index);
            order.insert(&mut txn, to_index, slide_id);
        }
        Ok(SlideReceipt {
            slide_id: slide_id.to_owned(),
            from_index: Some(from_index),
            to_index: Some(to_index),
        })
    }

    pub fn add_text_box(
        &self,
        context: &EditCtx,
        slide_id: &str,
        draft: &ShapeDraft,
    ) -> EditResult<ShapeReceipt> {
        validate_rect(draft.rect)?;
        crate::model::validate_xml_text(&draft.name)?;
        crate::model::validate_xml_text(&draft.text)?;
        crate::story::validate_style_values(
            draft.style.font_family.as_deref(),
            draft.style.underline.as_deref(),
            draft.style.color.as_deref(),
            draft.style.font_size_pt,
            draft.style.spacing_pt,
            draft.style.baseline_pct,
        )?;
        let shape_id = self.next_id("shape");
        let story_id = format!("story:{shape_id}:0");
        let paragraph_id = self.next_id("para");
        let mut txn = self.transact_for(context);
        let slide = slide_ref(&txn, slide_id)?;
        let order = slide_shape_order(&slide, &txn)?;
        let index = order.len(&txn);
        let shapes = required_map(&txn, SHAPES)?;
        let stories = required_map(&txn, STORIES)?;
        seed_plain_story(
            &stories,
            &mut txn,
            &story_id,
            &paragraph_id,
            &draft.text,
            &draft.style,
        );
        let shape = shapes.insert(&mut txn, shape_id.as_str(), MapPrelim::default());
        shape.insert(&mut txn, "id", shape_id.as_str());
        shape.insert(&mut txn, "sourceId", 0_f64);
        shape.insert(&mut txn, "kind", "shape");
        shape.insert(&mut txn, "name", draft.name.as_str());
        shape.insert(&mut txn, "x", draft.rect.x as f64);
        shape.insert(&mut txn, "y", draft.rect.y as f64);
        shape.insert(&mut txn, "width", draft.rect.width as f64);
        shape.insert(&mut txn, "height", draft.rect.height as f64);
        shape.insert(&mut txn, "rotationDeg", 0_f64);
        shape.insert(&mut txn, "flipH", false);
        shape.insert(&mut txn, "flipV", false);
        shape.insert(&mut txn, "geometry", "rect");
        insert_json(
            &shape,
            &mut txn,
            "fillJson",
            Some(&ShapeFill::named("none")),
        )?;
        shape.insert(
            &mut txn,
            "textStories",
            string_array(std::slice::from_ref(&story_id)),
        );
        shape.insert(&mut txn, "children", string_array(&[]));
        order.push_back(&mut txn, shape_id.as_str());
        Ok(ShapeReceipt {
            slide_id: slide_id.to_owned(),
            shape_id,
            index,
        })
    }

    pub fn add_shape(
        &self,
        context: &EditCtx,
        slide_id: &str,
        draft: &PresetShapeDraft,
    ) -> EditResult<ShapeReceipt> {
        validate_rect(draft.rect)?;
        crate::model::validate_xml_text(&draft.name)?;
        let aspect_ratio = draft.rect.width as f64 / draft.rect.height as f64;
        if preset_geometry_to_path(&draft.geometry, &Default::default(), aspect_ratio).is_none() {
            return Err(EditError::InvalidGeometry(format!(
                "unsupported preset geometry {}",
                draft.geometry
            )));
        }
        let fill = shape_fill(draft.fill.as_deref())?;
        let adjust_values = preset_geometry_default_adjustments(&draft.geometry)
            .into_iter()
            .collect::<BTreeMap<_, _>>();
        let shape_id = self.next_id("shape");
        let mut txn = self.transact_for(context);
        let slide = slide_ref(&txn, slide_id)?;
        let order = slide_shape_order(&slide, &txn)?;
        let index = order.len(&txn);
        let shapes = required_map(&txn, SHAPES)?;
        let shape = shapes.insert(&mut txn, shape_id.as_str(), MapPrelim::default());
        shape.insert(&mut txn, "id", shape_id.as_str());
        shape.insert(&mut txn, "sourceId", 0_f64);
        shape.insert(&mut txn, "kind", "shape");
        shape.insert(&mut txn, "name", draft.name.as_str());
        shape.insert(&mut txn, "x", draft.rect.x as f64);
        shape.insert(&mut txn, "y", draft.rect.y as f64);
        shape.insert(&mut txn, "width", draft.rect.width as f64);
        shape.insert(&mut txn, "height", draft.rect.height as f64);
        shape.insert(&mut txn, "rotationDeg", 0_f64);
        shape.insert(&mut txn, "flipH", false);
        shape.insert(&mut txn, "flipV", false);
        shape.insert(&mut txn, "geometry", draft.geometry.as_str());
        insert_json(&shape, &mut txn, "adjustValuesJson", Some(&adjust_values))?;
        insert_json(&shape, &mut txn, "fillJson", Some(&fill))?;
        shape.insert(&mut txn, "textStories", string_array(&[]));
        shape.insert(&mut txn, "children", string_array(&[]));
        order.push_back(&mut txn, shape_id.as_str());
        Ok(ShapeReceipt {
            slide_id: slide_id.to_owned(),
            shape_id,
            index,
        })
    }

    pub fn set_shape_fill(
        &self,
        context: &EditCtx,
        slide_id: &str,
        shape_id: &str,
        color: Option<&str>,
    ) -> EditResult<ShapeFillReceipt> {
        let fill = shape_fill(color)?;
        let mut txn = self.transact_for(context);
        require_shape_membership(&txn, slide_id, shape_id)?;
        let shape = shape_ref(&txn, shape_id)?;
        require_shape_kind(&shape, &txn)?;
        let before = optional_json::<ShapeFill, _>(&shape, &txn, "fillJson")?
            .as_ref()
            .and_then(fill_color);
        insert_json(&shape, &mut txn, "fillJson", Some(&fill))?;
        Ok(ShapeFillReceipt {
            slide_id: slide_id.to_owned(),
            shape_id: shape_id.to_owned(),
            before,
            after: fill_color(&fill),
        })
    }

    pub fn set_shape_stroke(
        &self,
        context: &EditCtx,
        slide_id: &str,
        shape_id: &str,
        stroke: &ShapeStroke,
    ) -> EditResult<ShapeStrokeReceipt> {
        let color = stroke.color.as_deref().map(color_value).transpose()?;
        if let Some(width) = stroke.width_pt
            && (!width.is_finite() || !(0.0..=1_000.0).contains(&width))
        {
            return Err(EditError::InvalidGeometry(format!(
                "stroke width {width}pt is outside the safe range"
            )));
        }
        let mut txn = self.transact_for(context);
        require_shape_membership(&txn, slide_id, shape_id)?;
        let shape = shape_ref(&txn, shape_id)?;
        require_shape_kind(&shape, &txn)?;
        let existing = optional_json::<ShapeOutline, _>(&shape, &txn, "outlineJson")?;
        let before = existing.as_ref().and_then(outline_stroke);
        let outline = if stroke.color.is_none() && stroke.width_pt.is_none() {
            ShapeOutline::default()
        } else {
            let mut outline = existing.unwrap_or_default();
            if let Some(color) = color {
                if outline.width.is_none() {
                    outline.width = Some(EMU_PER_POINT);
                }
                outline.color = Some(color);
                outline.gradient = None;
            } else if outline.color.is_none() && outline.gradient.is_none() {
                outline.color = Some(color_value("#000000")?);
            }
            if let Some(width) = stroke.width_pt {
                outline.width = Some(width * EMU_PER_POINT);
            }
            outline
        };
        insert_json(&shape, &mut txn, "outlineJson", Some(&outline))?;
        Ok(ShapeStrokeReceipt {
            slide_id: slide_id.to_owned(),
            shape_id: shape_id.to_owned(),
            before,
            after: outline_stroke(&outline),
        })
    }

    pub fn set_shape_adjust(
        &self,
        context: &EditCtx,
        slide_id: &str,
        shape_id: &str,
        adjustments: &BTreeMap<String, f64>,
    ) -> EditResult<ShapeAdjustReceipt> {
        validate_adjustments(adjustments)?;
        let mut txn = self.transact_for(context);
        require_shape_membership(&txn, slide_id, shape_id)?;
        let shape = shape_ref(&txn, shape_id)?;
        require_shape_kind(&shape, &txn)?;
        let geometry = required_string(&shape, &txn, "geometry")?;
        if geometry == "custom" {
            return Err(EditError::InvalidGeometry(
                "custom geometry does not support shape adjustments".to_owned(),
            ));
        }
        if !map_bool(&shape, &txn, "hasPresetGeometry").unwrap_or(true) {
            return Err(EditError::InvalidGeometry(
                "shape without preset geometry does not support shape adjustments".to_owned(),
            ));
        }
        let before = optional_json(&shape, &txn, "adjustValuesJson")?.unwrap_or_else(BTreeMap::new);
        let mut after = BTreeMap::new();
        for (name, value) in adjustments {
            let maximum = if geometry == "roundRect" && name == "adj" {
                0.5
            } else {
                1.0
            };
            after.insert(name.clone(), value.clamp(0.0, maximum));
        }
        insert_json(&shape, &mut txn, "adjustValuesJson", Some(&after))?;
        Ok(ShapeAdjustReceipt {
            slide_id: slide_id.to_owned(),
            shape_id: shape_id.to_owned(),
            before,
            after,
        })
    }

    pub fn remove_shape(
        &self,
        context: &EditCtx,
        slide_id: &str,
        shape_id: &str,
    ) -> EditResult<ShapeReceipt> {
        let mut txn = self.transact_for(context);
        let slide = slide_ref(&txn, slide_id)?;
        let order = slide_shape_order(&slide, &txn)?;
        let index = array_index(&order, &txn, shape_id)
            .ok_or_else(|| EditError::ShapeNotFound(shape_id.to_owned()))?;
        remove_shape_entries(&mut txn, &[shape_id.to_owned()])?;
        order.remove(&mut txn, index);
        Ok(ShapeReceipt {
            slide_id: slide_id.to_owned(),
            shape_id: shape_id.to_owned(),
            index,
        })
    }

    pub fn move_shape(
        &self,
        context: &EditCtx,
        slide_id: &str,
        shape_id: &str,
        x: i64,
        y: i64,
    ) -> EditResult<TransformReceipt> {
        validate_coordinate(x)?;
        validate_coordinate(y)?;
        let mut txn = self.transact_for(context);
        require_shape_membership(&txn, slide_id, shape_id)?;
        let shape = shape_ref(&txn, shape_id)?;
        let before = shape_rect(&shape, &txn)?;
        shape.insert(&mut txn, "x", x as f64);
        shape.insert(&mut txn, "y", y as f64);
        Ok(TransformReceipt {
            slide_id: slide_id.to_owned(),
            shape_id: shape_id.to_owned(),
            before,
            after: ShapeRect { x, y, ..before },
        })
    }

    pub fn resize_shape(
        &self,
        context: &EditCtx,
        slide_id: &str,
        shape_id: &str,
        width: i64,
        height: i64,
    ) -> EditResult<TransformReceipt> {
        let rect = ShapeRect {
            width,
            height,
            ..ShapeRect::default()
        };
        validate_rect(rect)?;
        let mut txn = self.transact_for(context);
        require_shape_membership(&txn, slide_id, shape_id)?;
        let shape = shape_ref(&txn, shape_id)?;
        let before = shape_rect(&shape, &txn)?;
        shape.insert(&mut txn, "width", width as f64);
        shape.insert(&mut txn, "height", height as f64);
        Ok(TransformReceipt {
            slide_id: slide_id.to_owned(),
            shape_id: shape_id.to_owned(),
            before,
            after: ShapeRect {
                width,
                height,
                ..before
            },
        })
    }

    pub fn set_shape_rect(
        &self,
        context: &EditCtx,
        slide_id: &str,
        shape_id: &str,
        rect: ShapeRect,
    ) -> EditResult<TransformReceipt> {
        validate_rect(rect)?;
        let mut txn = self.transact_for(context);
        require_shape_membership(&txn, slide_id, shape_id)?;
        let shape = shape_ref(&txn, shape_id)?;
        let before = shape_rect(&shape, &txn)?;
        shape.insert(&mut txn, "x", rect.x as f64);
        shape.insert(&mut txn, "y", rect.y as f64);
        shape.insert(&mut txn, "width", rect.width as f64);
        shape.insert(&mut txn, "height", rect.height as f64);
        Ok(TransformReceipt {
            slide_id: slide_id.to_owned(),
            shape_id: shape_id.to_owned(),
            before,
            after: rect,
        })
    }
}

pub(crate) fn validate_doc(doc: &Doc) -> EditResult<()> {
    let package = {
        let txn = doc.transact();
        let meta = required_map(&txn, META)?;
        validate_schema_version(&meta, &txn)?;
        if map_string(&meta, &txn, "fingerprint").is_none() {
            return Err(EditError::InvalidState("missing fingerprint".to_owned()));
        }
        package_from_meta(&meta, &txn)?
    };
    let snapshot = snapshot_doc(doc, &package)?;
    if snapshot.width_emu <= 0 || snapshot.height_emu <= 0 {
        return Err(EditError::InvalidState(
            "slide dimensions must be positive".to_owned(),
        ));
    }
    let txn = doc.transact();
    let stories = required_map(&txn, STORIES)?;
    for (story_id, value) in stories.iter(&txn) {
        let story = value
            .cast::<TextRef>()
            .map_err(|_| EditError::InvalidState(format!("story {story_id} is not text")))?;
        validate_story(&story, &txn, story_id)?;
    }
    Ok(())
}

pub(crate) fn package_from_doc(doc: &Doc) -> EditResult<PptxPackage> {
    let txn = doc.transact();
    let meta = required_map(&txn, META)?;
    validate_schema_version(&meta, &txn)?;
    package_from_meta(&meta, &txn)
}

pub(crate) fn import_source_render_data(doc: &Doc, source: &PptxPackage) -> EditResult<()> {
    let mut package = package_from_doc(doc)?;
    let sources = source
        .slides
        .iter()
        .map(|part| (&part.part_path, &part.shapes))
        .chain(
            source
                .layouts
                .iter()
                .map(|part| (&part.part_path, &part.shapes)),
        )
        .chain(
            source
                .masters
                .iter()
                .map(|part| (&part.part_path, &part.shapes)),
        )
        .collect::<HashMap<_, _>>();
    let mut changed = false;
    for (path, shapes) in package
        .slides
        .iter_mut()
        .map(|part| (&part.part_path, &mut part.shapes))
        .chain(
            package
                .layouts
                .iter_mut()
                .map(|part| (&part.part_path, &mut part.shapes)),
        )
        .chain(
            package
                .masters
                .iter_mut()
                .map(|part| (&part.part_path, &mut part.shapes)),
        )
    {
        if let Some(source) = sources.get(path) {
            changed |= merge_source_render_shapes(shapes, source);
        }
    }
    for master in &mut package.masters {
        if let Some(source) = source
            .masters
            .iter()
            .find(|source| source.part_path == master.part_path)
        {
            let target = &mut master.text_styles;
            let source = &source.text_styles;
            for (target, source) in target
                .title
                .iter_mut()
                .zip(&source.title)
                .chain(target.body.iter_mut().zip(&source.body))
                .chain(target.other.iter_mut().zip(&source.other))
            {
                changed |= merge_source_paragraph_properties(target, source);
            }
        }
    }
    for chart in &mut package.charts {
        if let Some(source) = source
            .charts
            .iter()
            .find(|source| source.part_path == chart.part_path)
        {
            changed |= merge_source_chart_properties(&mut chart.chart, &source.chart);
        }
    }
    for slide in &mut package.slides {
        if let Some(source) = source
            .slides
            .iter()
            .find(|source| source.part_path == slide.part_path)
            && slide.notes != source.notes
        {
            slide.notes.clone_from(&source.notes);
            changed = true;
        }
    }
    if package.table_styles != source.table_styles {
        package.table_styles.clone_from(&source.table_styles);
        changed = true;
    }
    if !changed {
        return Ok(());
    }
    let bytes = serde_json::to_vec(&package).map_err(|error| EditError::Json(error.to_string()))?;
    let mut txn = doc.transact_mut_with(MIGRATE_ORIGIN);
    let meta = required_map(&txn, META)?;
    meta.insert(&mut txn, "packageJson", Any::Buffer(Arc::from(bytes)));
    backfill_blip_effects(&mut txn, &package)?;
    backfill_tables(&mut txn, &package)?;
    Ok(())
}

fn merge_source_render_shapes(target: &mut [ShapeNode], source: &[ShapeNode]) -> bool {
    let mut changed = false;
    for source in source {
        let Some(target) = target
            .iter_mut()
            .find(|target| shape_base(target).id == shape_base(source).id)
        else {
            continue;
        };
        match (target, source) {
            (ShapeNode::Shape(target), ShapeNode::Shape(source)) => {
                changed |= target.picture_fill != source.picture_fill;
                target.picture_fill.clone_from(&source.picture_fill);
                if let (Some(target), Some(source)) = (&mut target.text, &source.text) {
                    changed |= merge_source_text_body(target, source);
                }
            }
            (ShapeNode::Picture(target), ShapeNode::Picture(source)) => {
                if target.effects.is_empty() && !source.effects.is_empty() {
                    target.effects.clone_from(&source.effects);
                    changed = true;
                }
            }
            (ShapeNode::Group(target), ShapeNode::Group(source)) => {
                changed |= merge_source_render_shapes(&mut target.children, &source.children);
            }
            (ShapeNode::GraphicFrame(target), ShapeNode::GraphicFrame(source)) => {
                if matches!(
                    target.data,
                    pptx_parse::GraphicFrameData::Unknown { picture: None, .. }
                ) && matches!(
                    source.data,
                    pptx_parse::GraphicFrameData::Unknown {
                        picture: Some(_),
                        ..
                    }
                ) {
                    target.data.clone_from(&source.data);
                    changed = true;
                }
                if let (
                    pptx_parse::GraphicFrameData::Table(target),
                    pptx_parse::GraphicFrameData::Table(source),
                ) = (&mut target.data, &source.data)
                {
                    changed |= merge_source_table(target, source);
                }
            }
            _ => {}
        }
    }
    changed
}

/// Copies the chart-space fill, axis lines, series lines and text properties a
/// source chart part declares.
fn merge_source_chart_properties(target: &mut ChartSpace, source: &ChartSpace) -> bool {
    let mut changed = target.fill != source.fill;
    target.fill.clone_from(&source.fill);
    changed |= target.text != source.text || target.title_text != source.title_text;
    target.text.clone_from(&source.text);
    target.title_text.clone_from(&source.title_text);
    if let (Some(target), Some(source)) = (&mut target.legend, &source.legend) {
        changed |= target.text != source.text;
        target.text.clone_from(&source.text);
    }
    for (target, source) in target.plot_groups.iter_mut().zip(&source.plot_groups) {
        for (target, source) in target.series.iter_mut().zip(&source.series) {
            changed |= target.line != source.line;
            target.line.clone_from(&source.line);
        }
    }
    let mut merge_axis = |target: Option<&mut ChartAxis>, source: Option<&ChartAxis>| {
        if let (Some(target), Some(source)) = (target, source) {
            changed |= target.line != source.line || target.text != source.text;
            target.line.clone_from(&source.line);
            target.text.clone_from(&source.text);
        }
    };
    if let (Some(target), Some(source)) = (&mut target.axes, &source.axes) {
        merge_axis(target.category.as_mut(), source.category.as_ref());
        merge_axis(target.value.as_mut(), source.value.as_ref());
    }
    if let (Some(target), Some(source)) = (&mut target.axis_list, &source.axis_list) {
        for (target, source) in target.iter_mut().zip(source) {
            merge_axis(Some(target), Some(source));
        }
    }
    changed
}

fn backfill_tables(txn: &mut TransactionMut<'_>, package: &PptxPackage) -> EditResult<()> {
    let shapes = required_map(txn, SHAPES)?;
    for (index, (slide, reference)) in package
        .slides
        .iter()
        .zip(&package.presentation.slides)
        .enumerate()
    {
        let slide_id = seeded_slide_id(index, reference.id);
        for (index, node) in slide.shapes.iter().enumerate() {
            backfill_table(txn, &shapes, &slide_id, &index.to_string(), node)?;
        }
    }
    Ok(())
}

fn backfill_table(
    txn: &mut TransactionMut<'_>,
    shapes: &MapRef,
    slide_id: &str,
    path: &str,
    node: &ShapeNode,
) -> EditResult<()> {
    if let ShapeNode::GraphicFrame(frame) = node
        && let pptx_parse::GraphicFrameData::Table(table) = &frame.data
        && !table.grid.is_empty()
        && let Some(shape) = shapes
            .get(txn, &seeded_shape_id(slide_id, path))
            .and_then(|value| value.cast::<MapRef>().ok())
        && matches!(
            optional_json::<pptx_parse::GraphicFrameData, _>(&shape, txn, "graphicJson")?,
            Some(pptx_parse::GraphicFrameData::Table(stored)) if stored.grid.is_empty()
        )
    {
        insert_json(&shape, txn, "graphicJson", Some(&frame.data))?;
    }
    if let ShapeNode::Group(group) = node {
        for (index, child) in group.children.iter().enumerate() {
            backfill_table(
                txn,
                shapes,
                slide_id,
                &seeded_child_path(path, index),
                child,
            )?;
        }
    }
    Ok(())
}

/// Restores the grid, spans and cell formatting a stored package dropped.
fn merge_source_table(target: &mut pptx_parse::Table, source: &pptx_parse::Table) -> bool {
    let mut changed = target.grid != source.grid || target.properties != source.properties;
    target.grid.clone_from(&source.grid);
    target.properties.clone_from(&source.properties);
    for (target, source) in target.rows.iter_mut().zip(&source.rows) {
        changed |= target.height != source.height;
        target.height = source.height;
        for (target, source) in target.cells.iter_mut().zip(&source.cells) {
            changed |= target.grid_span != source.grid_span
                || target.row_span != source.row_span
                || target.merged != source.merged
                || target.fill != source.fill
                || target.borders != source.borders;
            target.grid_span = source.grid_span;
            target.row_span = source.row_span;
            target.merged = source.merged;
            target.fill.clone_from(&source.fill);
            target.borders.clone_from(&source.borders);
            changed |= merge_source_text_body(&mut target.text, &source.text);
        }
    }
    changed
}

fn merge_source_text_body(
    target: &mut pptx_parse::TextBody,
    source: &pptx_parse::TextBody,
) -> bool {
    let mut changed = target.list_style != source.list_style
        || target.default_list_style != source.default_list_style
        || target.compat_line_spacing != source.compat_line_spacing
        || target.vertical_overflow != source.vertical_overflow
        || target.horizontal_overflow != source.horizontal_overflow;
    target.vertical_overflow = source.vertical_overflow;
    target.horizontal_overflow = source.horizontal_overflow;
    target.compat_line_spacing = source.compat_line_spacing;
    target.list_style.clone_from(&source.list_style);
    target
        .default_list_style
        .clone_from(&source.default_list_style);
    for (target, source) in target.paragraphs.iter_mut().zip(&source.paragraphs) {
        changed |= merge_source_paragraph_properties(&mut target.properties, &source.properties);
    }
    changed
}

fn merge_source_paragraph_properties(
    target: &mut pptx_parse::ParagraphProperties,
    source: &pptx_parse::ParagraphProperties,
) -> bool {
    let mut changed = target.bullet_font != source.bullet_font
        || target.bullet_color != source.bullet_color
        || target.bullet_size != source.bullet_size
        || target.line_spacing != source.line_spacing
        || target.margin_right != source.margin_right
        || target.space_before != source.space_before
        || target.space_after != source.space_after;
    target.line_spacing = source.line_spacing;
    target.margin_right = source.margin_right;
    target.space_before = source.space_before;
    target.space_after = source.space_after;
    if let (
        Some(pptx_parse::Bullet::AutoNumber {
            restart: target, ..
        }),
        Some(pptx_parse::Bullet::AutoNumber {
            restart: source, ..
        }),
    ) = (&mut target.bullet, &source.bullet)
    {
        changed |= *target != *source;
        *target = *source;
    }
    target.bullet_font.clone_from(&source.bullet_font);
    target.bullet_color.clone_from(&source.bullet_color);
    target.bullet_size.clone_from(&source.bullet_size);
    changed
}

pub(crate) fn fingerprint_from_doc(doc: &Doc) -> EditResult<String> {
    let txn = doc.transact();
    let meta = required_map(&txn, META)?;
    map_string(&meta, &txn, "fingerprint")
        .ok_or_else(|| EditError::InvalidState("missing fingerprint".to_owned()))
}

/// Carries a released 1.0 or 2.0 document forward to the current schema.
pub(crate) fn migrate_doc(doc: &Doc) -> EditResult<()> {
    let version = {
        let txn = doc.transact();
        let meta = required_map(&txn, META)?;
        schema_version(&meta, &txn)?
    };
    if version < SCHEMA_VERSION {
        migrate_doc_to_v2_1(doc)?;
    }
    Ok(())
}

/// Applies every schema change made since 2.0 in one transaction: the package is
/// rewritten through the current model, hidden flags and bitmap effects are
/// backfilled, the comment flavour is recorded, and everything a stored package
/// cannot carry -- baselines, outline gradients, character spacing, OLE picture
/// previews, chart and paragraph properties, table geometry -- is deferred to
/// [`import_source_render_data`] until the source is reattached.
fn migrate_doc_to_v2_1(doc: &Doc) -> EditResult<()> {
    let mut txn = doc.transact_mut_with(MIGRATE_ORIGIN);
    let meta = required_map(&txn, META)?;
    let package = package_from_meta(&meta, &txn)?;
    let package_json =
        serde_json::to_vec(&package).map_err(|error| EditError::Json(error.to_string()))?;
    meta.insert(
        &mut txn,
        "packageJson",
        Any::Buffer(Arc::from(package_json)),
    );
    backfill_hidden(&mut txn, &package)?;
    record_comment_flavor(&mut txn, &meta, &package);
    meta.insert(&mut txn, "baselinesPendingSource", true);
    meta.insert(&mut txn, "outlineGradientsPendingSource", true);
    backfill_blip_effects(&mut txn, &package)?;
    backfill_tables(&mut txn, &package)?;
    meta.insert(&mut txn, "spacingPendingSource", true);
    if package_needs_ole_source(&package) {
        meta.insert(&mut txn, "olePicturesPendingSource", true);
    }
    meta.insert(&mut txn, "schemaVersion", SCHEMA_VERSION);
    Ok(())
}

fn record_comment_flavor(txn: &mut TransactionMut<'_>, meta: &MapRef, package: &PptxPackage) {
    if meta.contains_key(txn, "commentFlavor") {
        return;
    }
    if !package.comments.is_empty()
        || package
            .relationships
            .values()
            .flatten()
            .any(|relationship| {
                relationship.is_type(pptx_parse::relationship_types::COMMENTS)
                    || relationship.is_type(pptx_parse::relationship_types::MODERN_COMMENTS)
            })
    {
        meta.insert(txn, "commentsPendingSource", true);
    }
    meta.insert(
        txn,
        "commentFlavor",
        flavor_key(package.comment_flavor.unwrap_or_default()),
    );
}

fn backfill_blip_effects(txn: &mut TransactionMut<'_>, package: &PptxPackage) -> EditResult<()> {
    let shapes = required_map(txn, SHAPES)?;
    for (index, (slide, reference)) in package
        .slides
        .iter()
        .zip(&package.presentation.slides)
        .enumerate()
    {
        let slide_id = seeded_slide_id(index, reference.id);
        for (index, node) in slide.shapes.iter().enumerate() {
            backfill_picture_effects(txn, &shapes, &slide_id, &index.to_string(), node)?;
        }
    }
    Ok(())
}

fn backfill_picture_effects(
    txn: &mut TransactionMut<'_>,
    shapes: &MapRef,
    slide_id: &str,
    path: &str,
    node: &ShapeNode,
) -> EditResult<()> {
    match node {
        ShapeNode::Picture(picture) if !picture.effects.is_empty() => {
            let id = seeded_shape_id(slide_id, path);
            if let Some(shape) = shapes
                .get(txn, &id)
                .and_then(|shape| shape.cast::<MapRef>().ok())
                && !shape.contains_key(txn, "blipEffectsJson")
            {
                insert_json(&shape, txn, "blipEffectsJson", Some(&picture.effects))?;
            }
        }
        ShapeNode::Group(group) => {
            for (index, child) in group.children.iter().enumerate() {
                backfill_picture_effects(
                    txn,
                    shapes,
                    slide_id,
                    &seeded_child_path(path, index),
                    child,
                )?;
            }
        }
        _ => {}
    }
    Ok(())
}

fn package_needs_ole_source(package: &PptxPackage) -> bool {
    package
        .slides
        .iter()
        .any(|part| needs_ole_source(&part.shapes))
        || package
            .layouts
            .iter()
            .any(|part| needs_ole_source(&part.shapes))
        || package
            .masters
            .iter()
            .any(|part| needs_ole_source(&part.shapes))
}

fn needs_ole_source(nodes: &[ShapeNode]) -> bool {
    nodes.iter().any(|node| match node {
        ShapeNode::GraphicFrame(frame) => matches!(&frame.data,
            pptx_parse::GraphicFrameData::Unknown { uri: Some(uri), picture: None }
                if uri == "http://schemas.openxmlformats.org/presentationml/2006/ole"),
        ShapeNode::Group(group) => needs_ole_source(&group.children),
        _ => false,
    })
}

pub(crate) fn import_source_ole_pictures(doc: &Doc, source: &PptxPackage) -> EditResult<()> {
    let mut txn = doc.transact_mut_with(MIGRATE_ORIGIN);
    let meta = required_map(&txn, META)?;
    if map_bool(&meta, &txn, "olePicturesPendingSource") != Some(true) {
        return Ok(());
    }
    let shapes = required_map(&txn, SHAPES)?;
    for (index, (slide, reference)) in source
        .slides
        .iter()
        .zip(&source.presentation.slides)
        .enumerate()
    {
        let slide_id = seeded_slide_id(index, reference.id);
        for (index, node) in slide.shapes.iter().enumerate() {
            backfill_ole_picture(&mut txn, &shapes, &slide_id, &index.to_string(), node)?;
        }
    }
    meta.remove(&mut txn, "olePicturesPendingSource");
    Ok(())
}

fn backfill_ole_picture(
    txn: &mut TransactionMut<'_>,
    shapes: &MapRef,
    slide_id: &str,
    path: &str,
    node: &ShapeNode,
) -> EditResult<()> {
    if let ShapeNode::GraphicFrame(frame) = node
        && matches!(
            frame.data,
            pptx_parse::GraphicFrameData::Unknown {
                picture: Some(_),
                ..
            }
        )
        && let Some(shape) = shapes
            .get(txn, &seeded_shape_id(slide_id, path))
            .and_then(|value| value.cast::<MapRef>().ok())
        && matches!(
            optional_json::<pptx_parse::GraphicFrameData, _>(&shape, txn, "graphicJson")?,
            Some(pptx_parse::GraphicFrameData::Unknown { picture: None, .. })
        )
    {
        insert_json(&shape, txn, "graphicJson", Some(&frame.data))?;
    }
    if let ShapeNode::Group(group) = node {
        for (index, child) in group.children.iter().enumerate() {
            backfill_ole_picture(
                txn,
                shapes,
                slide_id,
                &seeded_child_path(path, index),
                child,
            )?;
        }
    }
    Ok(())
}

fn backfill_hidden(txn: &mut TransactionMut<'_>, package: &PptxPackage) -> EditResult<()> {
    let shapes = required_map(txn, SHAPES)?;
    for shape_id in seeded_hidden_shape_ids(package) {
        if let Some(shape) = shapes
            .get(txn, &shape_id)
            .and_then(|value| value.cast::<MapRef>().ok())
        {
            shape.insert(txn, "hidden", true);
        }
    }
    Ok(())
}

fn seeded_hidden_shape_ids(package: &PptxPackage) -> Vec<String> {
    let mut ids = Vec::new();
    for (slide_index, (slide, reference)) in package
        .slides
        .iter()
        .zip(&package.presentation.slides)
        .enumerate()
    {
        let slide_id = seeded_slide_id(slide_index, reference.id);
        for (shape_index, shape) in slide.shapes.iter().enumerate() {
            collect_hidden_shape_ids(&slide_id, &shape_index.to_string(), shape, &mut ids);
        }
    }
    ids
}

fn collect_hidden_shape_ids(slide_id: &str, path: &str, shape: &ShapeNode, ids: &mut Vec<String>) {
    if shape_base(shape).hidden {
        ids.push(seeded_shape_id(slide_id, path));
    }
    if let ShapeNode::Group(group) = shape {
        for (child_index, child) in group.children.iter().enumerate() {
            collect_hidden_shape_ids(slide_id, &seeded_child_path(path, child_index), child, ids);
        }
    }
}

fn schema_version<T: ReadTxn>(meta: &MapRef, txn: &T) -> EditResult<f64> {
    map_number(meta, txn, "schemaVersion")
        .filter(|version| MIGRATABLE_SCHEMA_VERSIONS.contains(version))
        .ok_or_else(|| EditError::InvalidState("unsupported deck schema version".to_owned()))
}

fn validate_schema_version<T: ReadTxn>(meta: &MapRef, txn: &T) -> EditResult<()> {
    schema_version(meta, txn).map(|_| ())
}

fn package_from_meta<T: ReadTxn>(meta: &MapRef, txn: &T) -> EditResult<PptxPackage> {
    let Some(Out::Any(Any::Buffer(bytes))) = meta.get(txn, "packageJson") else {
        return Err(EditError::InvalidState("missing package data".to_owned()));
    };
    serde_json::from_slice(&bytes).map_err(|error| EditError::InvalidState(error.to_string()))
}

pub(crate) fn snapshot_doc(doc: &Doc, package: &PptxPackage) -> EditResult<DeckSnapshot> {
    let txn = doc.transact();
    let meta = required_map(&txn, META)?;
    let order = required_order(&txn)?;
    let slides = required_map(&txn, SLIDES)?;
    let shapes = required_map(&txn, SHAPES)?;
    let stories = required_map(&txn, STORIES)?;
    let mut seen_slides = HashSet::new();
    let mut slide_snapshots = Vec::new();
    for slide_id in string_array_ref(&order, &txn) {
        if !seen_slides.insert(slide_id.clone()) {
            continue;
        }
        let slide = slides
            .get(&txn, &slide_id)
            .and_then(|value| value.cast::<MapRef>().ok())
            .ok_or_else(|| EditError::InvalidState(format!("missing slide {slide_id}")))?;
        let source_part_path = map_string(&slide, &txn, "sourcePartPath");
        let layout_part_path = map_string(&slide, &txn, "layoutPartPath");
        let theme = theme_for_layout(package, layout_part_path.as_deref());
        let shape_order = slide_shape_order(&slide, &txn)?;
        let mut seen_shapes = HashSet::new();
        let mut shape_snapshots = Vec::new();
        for shape_id in string_array_ref(&shape_order, &txn) {
            if seen_shapes.insert(shape_id.clone()) {
                shape_snapshots.push(snapshot_shape(
                    &shapes,
                    &stories,
                    &txn,
                    &shape_id,
                    &mut HashSet::new(),
                    theme,
                )?);
            }
        }
        let notes = map_string(&slide, &txn, "notes").unwrap_or_else(|| {
            package
                .slides
                .iter()
                .find(|source| Some(&source.part_path) == source_part_path.as_ref())
                .map(|source| source.notes.clone())
                .unwrap_or_default()
        });
        slide_snapshots.push(SlideSnapshot {
            id: slide_id,
            source_part_path,
            layout_part_path,
            name: map_string(&slide, &txn, "name"),
            notes,
            shapes: shape_snapshots,
        });
    }
    Ok(DeckSnapshot {
        width_emu: required_i64(&meta, &txn, "widthEmu")?,
        height_emu: required_i64(&meta, &txn, "heightEmu")?,
        slides: slide_snapshots,
        comment_flavor: snapshot_flavor(&txn)?,
        comments: snapshot_comments(&txn)?,
    })
}

fn snapshot_shape<T: ReadTxn>(
    shapes: &MapRef,
    stories: &MapRef,
    txn: &T,
    shape_id: &str,
    visiting: &mut HashSet<String>,
    theme: Option<&Theme>,
) -> EditResult<ShapeSnapshot> {
    if visiting.len() >= MAX_SHAPE_DEPTH {
        return Err(EditError::InvalidState(format!(
            "shape nesting exceeds {MAX_SHAPE_DEPTH} levels"
        )));
    }
    if !visiting.insert(shape_id.to_owned()) {
        return Err(EditError::InvalidState(format!(
            "shape cycle at {shape_id}"
        )));
    }
    let shape = shapes
        .get(txn, shape_id)
        .and_then(|value| value.cast::<MapRef>().ok())
        .ok_or_else(|| EditError::InvalidState(format!("missing shape {shape_id}")))?;
    let mut text_snapshots = Vec::new();
    for story_id in map_string_array(&shape, txn, "textStories")? {
        let story = stories
            .get(txn, &story_id)
            .and_then(|value| value.cast::<TextRef>().ok())
            .ok_or_else(|| EditError::InvalidState(format!("missing story {story_id}")))?;
        text_snapshots.push(snapshot_story(&story, txn, &story_id)?);
    }
    let mut children = Vec::new();
    for child_id in map_string_array(&shape, txn, "children")? {
        children.push(snapshot_shape(
            shapes, stories, txn, &child_id, visiting, theme,
        )?);
    }
    visiting.remove(shape_id);
    let fill: Option<ShapeFill> = optional_json(&shape, txn, "fillJson")?;
    let outline: Option<ShapeOutline> = optional_json(&shape, txn, "outlineJson")?;
    let resolved_fill_color = fill
        .as_ref()
        .filter(|fill| fill.fill_type != "none")
        .and_then(|fill| resolve_color_value_to_hex_with_theme(fill.color.as_ref(), theme));
    let resolved_outline_color = outline
        .as_ref()
        .and_then(|outline| resolve_color_value_to_hex_with_theme(outline.color.as_ref(), theme));
    Ok(ShapeSnapshot {
        id: shape_id.to_owned(),
        source_id: required_u32(&shape, txn, "sourceId")?,
        kind: parse_shape_kind(&required_string(&shape, txn, "kind")?)?,
        name: required_string(&shape, txn, "name")?,
        x: required_i64(&shape, txn, "x")?,
        y: required_i64(&shape, txn, "y")?,
        width: required_i64(&shape, txn, "width")?,
        height: required_i64(&shape, txn, "height")?,
        rotation_deg: map_number(&shape, txn, "rotationDeg").unwrap_or_default(),
        flip_h: map_bool(&shape, txn, "flipH").unwrap_or_default(),
        flip_v: map_bool(&shape, txn, "flipV").unwrap_or_default(),
        hidden: map_bool(&shape, txn, "hidden").unwrap_or_default(),
        geometry: required_string(&shape, txn, "geometry")?,
        adjust_values: optional_json(&shape, txn, "adjustValuesJson")?.unwrap_or_default(),
        placeholder: optional_json(&shape, txn, "placeholderJson")?,
        fill,
        resolved_fill_color,
        outline,
        resolved_outline_color,
        media_part_path: map_string(&shape, txn, "mediaPartPath"),
        blip_effects: optional_json(&shape, txn, "blipEffectsJson")?.unwrap_or_default(),
        graphic: optional_json(&shape, txn, "graphicJson")?,
        text_stories: text_snapshots,
        children,
    })
}

fn parse_shape_kind(value: &str) -> EditResult<ShapeKind> {
    match value {
        "shape" => Ok(ShapeKind::Shape),
        "picture" => Ok(ShapeKind::Picture),
        "graphicFrame" => Ok(ShapeKind::GraphicFrame),
        "group" => Ok(ShapeKind::Group),
        _ => Err(EditError::InvalidState(format!(
            "unknown shape kind {value}"
        ))),
    }
}

fn required_order<T: ReadTxn>(txn: &T) -> EditResult<ArrayRef> {
    txn.get_array(SLIDE_ORDER)
        .ok_or_else(|| EditError::InvalidState("missing slide order".to_owned()))
}

pub(crate) fn required_map<T: ReadTxn>(txn: &T, name: &str) -> EditResult<MapRef> {
    txn.get_map(name)
        .ok_or_else(|| EditError::InvalidState(format!("missing {name}")))
}

pub(crate) fn slide_ref<T: ReadTxn>(txn: &T, slide_id: &str) -> EditResult<MapRef> {
    required_map(txn, SLIDES)?
        .get(txn, slide_id)
        .and_then(|value| value.cast::<MapRef>().ok())
        .ok_or_else(|| EditError::SlideNotFound(slide_id.to_owned()))
}

fn shape_ref<T: ReadTxn>(txn: &T, shape_id: &str) -> EditResult<MapRef> {
    required_map(txn, SHAPES)?
        .get(txn, shape_id)
        .and_then(|value| value.cast::<MapRef>().ok())
        .ok_or_else(|| EditError::ShapeNotFound(shape_id.to_owned()))
}

fn require_shape_kind<T: ReadTxn>(shape: &MapRef, txn: &T) -> EditResult<()> {
    if required_string(shape, txn, "kind")? == "shape" {
        Ok(())
    } else {
        Err(EditError::InvalidGeometry(
            "only preset shapes support shape styling".to_owned(),
        ))
    }
}

fn slide_shape_order<T: ReadTxn>(slide: &MapRef, txn: &T) -> EditResult<ArrayRef> {
    slide
        .get(txn, "shapes")
        .and_then(|value| value.cast::<ArrayRef>().ok())
        .ok_or_else(|| EditError::InvalidState("slide has no shape order".to_owned()))
}

fn require_shape_membership<T: ReadTxn>(txn: &T, slide_id: &str, shape_id: &str) -> EditResult<()> {
    let slide = slide_ref(txn, slide_id)?;
    let order = slide_shape_order(&slide, txn)?;
    if array_index(&order, txn, shape_id).is_some() {
        Ok(())
    } else {
        Err(EditError::ShapeNotFound(shape_id.to_owned()))
    }
}

fn remove_shape_entries(txn: &mut TransactionMut<'_>, root_shape_ids: &[String]) -> EditResult<()> {
    let shapes = required_map(txn, SHAPES)?;
    let stories = required_map(txn, STORIES)?;
    let mut entries = ShapeEntries::default();
    for shape_id in root_shape_ids {
        collect_shape_entries(&shapes, txn, shape_id, &mut HashSet::new(), &mut entries)?;
    }
    for story_id in entries.story_ids {
        stories.remove(txn, &story_id);
    }
    for shape_id in entries.shape_ids {
        shapes.remove(txn, &shape_id);
    }
    Ok(())
}

#[derive(Default)]
struct ShapeEntries {
    shape_ids: Vec<String>,
    seen_shape_ids: HashSet<String>,
    story_ids: Vec<String>,
    seen_story_ids: HashSet<String>,
}

fn collect_shape_entries<T: ReadTxn>(
    shapes: &MapRef,
    txn: &T,
    shape_id: &str,
    visiting: &mut HashSet<String>,
    entries: &mut ShapeEntries,
) -> EditResult<()> {
    if visiting.len() >= MAX_SHAPE_DEPTH {
        return Err(EditError::InvalidState(format!(
            "shape nesting exceeds {MAX_SHAPE_DEPTH} levels"
        )));
    }
    if !visiting.insert(shape_id.to_owned()) {
        return Err(EditError::InvalidState(format!(
            "shape cycle at {shape_id}"
        )));
    }
    if entries.seen_shape_ids.contains(shape_id) {
        visiting.remove(shape_id);
        return Ok(());
    }
    let shape = shapes
        .get(txn, shape_id)
        .and_then(|value| value.cast::<MapRef>().ok())
        .ok_or_else(|| EditError::ShapeNotFound(shape_id.to_owned()))?;
    for story_id in map_string_array(&shape, txn, "textStories")? {
        if entries.seen_story_ids.insert(story_id.clone()) {
            entries.story_ids.push(story_id);
        }
    }
    for child_id in map_string_array(&shape, txn, "children")? {
        collect_shape_entries(shapes, txn, &child_id, visiting, entries)?;
    }
    visiting.remove(shape_id);
    entries.seen_shape_ids.insert(shape_id.to_owned());
    entries.shape_ids.push(shape_id.to_owned());
    Ok(())
}

fn array_index<T: ReadTxn>(array: &ArrayRef, txn: &T, value: &str) -> Option<u32> {
    array
        .iter(txn)
        .enumerate()
        .find(|(_, item)| out_string(item).as_deref() == Some(value))
        .map(|(index, _)| index as u32)
}

fn string_array_ref<T: ReadTxn>(array: &ArrayRef, txn: &T) -> Vec<String> {
    array
        .iter(txn)
        .filter_map(|value| out_string(&value))
        .collect()
}

fn map_string_array<T: ReadTxn>(map: &MapRef, txn: &T, key: &str) -> EditResult<Vec<String>> {
    match map.get(txn, key) {
        Some(Out::Any(Any::Array(values))) => Ok(values
            .iter()
            .filter_map(|value| match value {
                Any::String(value) => Some(value.to_string()),
                _ => None,
            })
            .collect()),
        None => Ok(Vec::new()),
        _ => Err(EditError::InvalidState(format!("{key} is not an array"))),
    }
}

fn string_array(values: &[String]) -> Any {
    Any::Array(Arc::from(
        values
            .iter()
            .map(|value| Any::from(value.as_str()))
            .collect::<Vec<_>>(),
    ))
}

fn shape_rect<T: ReadTxn>(shape: &MapRef, txn: &T) -> EditResult<ShapeRect> {
    Ok(ShapeRect {
        x: required_i64(shape, txn, "x")?,
        y: required_i64(shape, txn, "y")?,
        width: required_i64(shape, txn, "width")?,
        height: required_i64(shape, txn, "height")?,
    })
}

fn required_u32<T: ReadTxn>(map: &MapRef, txn: &T, key: &str) -> EditResult<u32> {
    let value = required_i64(map, txn, key)?;
    u32::try_from(value).map_err(|_| {
        EditError::InvalidState(format!("{key} value {value} is outside the u32 range"))
    })
}

fn validate_rect(rect: ShapeRect) -> EditResult<()> {
    validate_coordinate(rect.x)?;
    validate_coordinate(rect.y)?;
    if rect.width <= 0 || rect.height <= 0 {
        return Err(EditError::InvalidGeometry(
            "shape width and height must be positive".to_owned(),
        ));
    }
    validate_coordinate(rect.width)?;
    validate_coordinate(rect.height)
}

fn validate_coordinate(value: i64) -> EditResult<()> {
    if value.unsigned_abs() > MAX_GEOMETRY as u64 {
        return Err(EditError::InvalidGeometry(format!(
            "coordinate {value} exceeds the safe range"
        )));
    }
    Ok(())
}

fn validate_adjustments(adjustments: &BTreeMap<String, f64>) -> EditResult<()> {
    if adjustments.len() > MAX_ADJUSTMENTS {
        return Err(EditError::InvalidAdjustment(format!(
            "at most {MAX_ADJUSTMENTS} values are allowed"
        )));
    }
    for (name, value) in adjustments {
        if !valid_adjustment_name(name) {
            return Err(EditError::InvalidAdjustment(format!(
                "unrecognized guide name {name:?}"
            )));
        }
        if !value.is_finite() {
            return Err(EditError::InvalidAdjustment(format!(
                "guide {name:?} must be finite"
            )));
        }
    }
    Ok(())
}

fn valid_adjustment_name(name: &str) -> bool {
    if name == "adj" {
        return true;
    }
    let Some(index) = name.strip_prefix("adj") else {
        return false;
    };
    index
        .parse::<usize>()
        .ok()
        .filter(|value| value.to_string() == index)
        .is_some_and(|value| (1..=MAX_ADJUSTMENT_INDEX).contains(&value))
}

fn shape_fill(color: Option<&str>) -> EditResult<ShapeFill> {
    Ok(match color {
        Some(color) => ShapeFill {
            fill_type: "solid".to_owned(),
            color: Some(color_value(color)?),
            gradient: None,
        },
        None => ShapeFill::named("none"),
    })
}

fn fill_color(fill: &ShapeFill) -> Option<String> {
    (fill.fill_type != "none")
        .then(|| resolve_color_value_to_hex(fill.color.as_ref()))
        .flatten()
}

fn outline_stroke(outline: &ShapeOutline) -> Option<ShapeStroke> {
    Some(ShapeStroke {
        color: Some(resolve_color_value_to_hex(outline.color.as_ref())?),
        width_pt: outline.width.map(|width| width / EMU_PER_POINT),
    })
}

fn color_value(color: &str) -> EditResult<ColorValue> {
    let rgb = color.strip_prefix('#').unwrap_or(color);
    if rgb.len() != 6 || !rgb.bytes().all(|byte| byte.is_ascii_hexdigit()) {
        return Err(EditError::InvalidGeometry(format!(
            "color {color:?} must be a six-digit hex value"
        )));
    }
    Ok(ColorValue {
        rgb: Some(rgb.to_ascii_uppercase()),
        ..ColorValue::default()
    })
}

fn required_string<T: ReadTxn>(map: &MapRef, txn: &T, key: &str) -> EditResult<String> {
    map_string(map, txn, key)
        .ok_or_else(|| EditError::InvalidState(format!("missing string {key}")))
}

pub(crate) fn map_string<T: ReadTxn>(map: &MapRef, txn: &T, key: &str) -> Option<String> {
    map.get(txn, key).and_then(|value| out_string(&value))
}

fn out_string(value: &Out) -> Option<String> {
    match value {
        Out::Any(Any::String(value)) => Some(value.to_string()),
        _ => None,
    }
}

fn required_i64<T: ReadTxn>(map: &MapRef, txn: &T, key: &str) -> EditResult<i64> {
    let number = map_number(map, txn, key)
        .ok_or_else(|| EditError::InvalidState(format!("missing number {key}")))?;
    if !number.is_finite() || number.fract() != 0.0 || number.abs() > MAX_GEOMETRY as f64 {
        return Err(EditError::InvalidState(format!("invalid integer {key}")));
    }
    Ok(number as i64)
}

pub(crate) fn map_number<T: ReadTxn>(map: &MapRef, txn: &T, key: &str) -> Option<f64> {
    match map.get(txn, key) {
        Some(Out::Any(Any::Number(value))) if value.is_finite() => Some(value),
        Some(Out::Any(Any::BigInt(value))) => Some(value as f64),
        _ => None,
    }
}

pub(crate) fn map_bool<T: ReadTxn>(map: &MapRef, txn: &T, key: &str) -> Option<bool> {
    match map.get(txn, key) {
        Some(Out::Any(Any::Bool(value))) => Some(value),
        _ => None,
    }
}

fn optional_json<T: DeserializeOwned, R: ReadTxn>(
    map: &MapRef,
    txn: &R,
    key: &str,
) -> EditResult<Option<T>> {
    map_string(map, txn, key)
        .map(|json| {
            serde_json::from_str(&json).map_err(|error| EditError::InvalidState(error.to_string()))
        })
        .transpose()
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::TextStyle;

    const FIXTURE: &[u8] = include_bytes!("../../../apps/demo/public/betteroffice-demo.pptx");
    const HIDDEN_FIXTURE: &[u8] = include_bytes!("../tests/fixtures/hidden-shapes.pptx");

    #[test]
    fn a_reattached_source_restores_the_series_lines_a_stored_package_lacks() {
        let source = ChartSpace {
            plot_groups: vec![pptx_parse::ChartPlotGroup {
                series: vec![pptx_parse::ChartSeries {
                    line: Some(ooxml_drawingml::chart::ChartLine {
                        none: false,
                        color: Some("#FFFFFF".to_owned()),
                        width_emu: Some(41275.0),
                    }),
                    ..pptx_parse::ChartSeries::default()
                }],
                ..pptx_parse::ChartPlotGroup::default()
            }],
            ..ChartSpace::default()
        };
        let mut target = source.clone();
        target.plot_groups[0].series[0].line = None;

        assert!(merge_source_chart_properties(&mut target, &source));
        assert_eq!(target, source);
        assert!(!merge_source_chart_properties(&mut target, &source));
    }

    #[test]
    fn a_reattached_source_restores_the_right_margin_a_stored_package_lacks() {
        let source = pptx_parse::ParagraphProperties {
            margin_right: Some(914_400),
            ..pptx_parse::ParagraphProperties::default()
        };
        let mut target = pptx_parse::ParagraphProperties::default();

        assert!(merge_source_paragraph_properties(&mut target, &source));
        assert_eq!(target.margin_right, Some(914_400));
        assert!(!merge_source_paragraph_properties(&mut target, &source));
    }

    #[test]
    fn a_reattached_source_restores_the_paragraph_spacing_a_stored_package_lacks() {
        let source = pptx_parse::ParagraphProperties {
            space_before: Some(pptx_parse::LineSpacing::Points { value: 10.0 }),
            space_after: Some(pptx_parse::LineSpacing::Percent { value: 0.2 }),
            ..pptx_parse::ParagraphProperties::default()
        };
        let mut target = pptx_parse::ParagraphProperties::default();

        assert!(merge_source_paragraph_properties(&mut target, &source));
        assert_eq!(target.space_before, source.space_before);
        assert_eq!(target.space_after, source.space_after);
        assert!(!merge_source_paragraph_properties(&mut target, &source));
    }

    #[test]
    fn attaching_a_source_refreshes_chart_text_a_stored_package_never_carried() {
        use ooxml_drawingml::chart::{ChartLegend, ChartTextProperties};

        let styled = ChartTextProperties {
            spacing_pt: Some(3.0),
            ..ChartTextProperties::default()
        };
        let source = ChartSpace {
            text: Some(styled.clone()),
            title_text: Some(styled.clone()),
            legend: Some(ChartLegend {
                visible: true,
                text: Some(styled.clone()),
                ..ChartLegend::default()
            }),
            axis_list: Some(vec![ChartAxis {
                text: Some(styled.clone()),
                ..ChartAxis::default()
            }]),
            ..ChartSpace::default()
        };
        let mut target = ChartSpace {
            legend: Some(ChartLegend {
                visible: true,
                ..ChartLegend::default()
            }),
            axis_list: Some(vec![ChartAxis::default()]),
            ..ChartSpace::default()
        };
        assert!(merge_source_chart_properties(&mut target, &source));
        assert_eq!(target.text.as_ref(), Some(&styled));
        assert_eq!(target.title_text.as_ref(), Some(&styled));
        assert_eq!(target.legend.unwrap().text.as_ref(), Some(&styled));
        assert_eq!(target.axis_list.unwrap()[0].text.as_ref(), Some(&styled));
        assert!(!merge_source_chart_properties(&mut source.clone(), &source));
    }

    #[test]
    fn an_unmigratable_schema_version_is_reported_before_package_json() {
        let session = DeckSession::open(FIXTURE, 100).unwrap();
        {
            let mut txn = session.doc.transact_mut();
            let meta = required_map(&txn, META).unwrap();
            meta.insert(&mut txn, "schemaVersion", SCHEMA_VERSION + 1.0);
            meta.insert(
                &mut txn,
                "packageJson",
                Any::Buffer(Arc::from(b"{}".to_vec())),
            );
        }

        assert!(matches!(
            validate_doc(&session.doc),
            Err(EditError::InvalidState(message))
                if message == "unsupported deck schema version"
        ));
        assert!(matches!(
            DeckSession::open_from_update(&session.encode_state_as_update_v1(), 101),
            Err(EditError::InvalidState(message))
                if message == "unsupported deck schema version"
        ));
    }

    #[test]
    fn migration_leaves_a_current_document_untouched() {
        let session = DeckSession::open(FIXTURE, 102).unwrap();
        let before = session.encode_state_as_update_v1();
        migrate_doc(&session.doc).unwrap();
        assert_eq!(session.encode_state_as_update_v1(), before);
    }

    #[test]
    fn legacy_migrations_commit_once_and_normalise_the_package() {
        use std::sync::Mutex;

        const V1: &[u8] = include_bytes!("../tests/fixtures/deck-schema-v1.update.bin");
        const V2: &[u8] = include_bytes!("../tests/fixtures/deck-schema-v2-connectors.update.bin");
        for update in [V1, V2] {
            let doc = crate::doc_with_client_id(920);
            crate::hydrate_doc(&doc, update).unwrap();
            let before = snapshot_doc(&doc, &package_from_doc(&doc).unwrap()).unwrap();
            let observed = Arc::new(Mutex::new(Vec::new()));
            let events = observed.clone();
            let _subscription = doc
                .observe_update_v1(move |txn, _| {
                    let meta = required_map(txn, META).unwrap();
                    let Some(Out::Any(Any::Buffer(package))) = meta.get(txn, "packageJson") else {
                        panic!("missing package data");
                    };
                    events
                        .lock()
                        .unwrap()
                        .push((map_number(&meta, txn, "schemaVersion").unwrap(), package));
                })
                .unwrap();

            migrate_doc(&doc).unwrap();

            let events = observed.lock().unwrap();
            assert_eq!(
                events
                    .iter()
                    .map(|(version, _)| *version)
                    .collect::<Vec<_>>(),
                [SCHEMA_VERSION]
            );
            for (_, package) in events.iter() {
                let json: serde_json::Value = serde_json::from_slice(package).unwrap();
                assert!(json.get("charts").unwrap().is_array());
                assert!(json.get("shapeElements").is_none());
                assert!(json["presentation"].get("firstSlideNum").is_none());
            }
            let package = package_from_doc(&doc).unwrap();
            assert_eq!(snapshot_doc(&doc, &package).unwrap(), before);
            assert!(!package.models_connectors());
            assert_eq!(package.presentation.first_slide_num, 1);
        }
    }

    #[test]
    fn a_v2_hidden_snapshot_backfills_flags_without_rewriting_the_package() {
        use std::sync::Mutex;
        use yrs::Update;
        use yrs::updates::decoder::Decode;

        const V2: &[u8] = include_bytes!("../tests/fixtures/deck-schema-v2-hidden.update.bin");
        let doc = crate::doc_with_client_id(9430);
        doc.transact_mut()
            .apply_update(Update::decode_v1(V2).unwrap())
            .unwrap();
        let before = package_from_doc(&doc).unwrap();
        let observed = Arc::new(Mutex::new(Vec::new()));
        let events = observed.clone();
        let _subscription = doc
            .observe_update_v1(move |txn, _| {
                let meta = required_map(txn, META).unwrap();
                let shapes = required_map(txn, SHAPES).unwrap();
                let mut hidden: Vec<String> = shapes
                    .iter(txn)
                    .filter_map(|(id, value)| value.cast::<MapRef>().ok().map(|shape| (id, shape)))
                    .filter(|(_, shape)| map_bool(shape, txn, "hidden").unwrap_or(false))
                    .map(|(id, _)| id.to_owned())
                    .collect();
                hidden.sort();
                events.lock().unwrap().push((
                    map_number(&meta, txn, "schemaVersion").unwrap(),
                    package_from_meta(&meta, txn).unwrap(),
                    hidden,
                ));
            })
            .unwrap();
        migrate_doc(&doc).unwrap();
        let events = observed.lock().unwrap();
        assert_eq!(
            events
                .iter()
                .map(|(version, _, _)| *version)
                .collect::<Vec<_>>(),
            [SCHEMA_VERSION]
        );
        for (_, package, hidden) in events.iter() {
            assert_eq!(
                serde_json::to_vec(package).unwrap(),
                serde_json::to_vec(&before).unwrap()
            );
            assert_eq!(
                hidden,
                &[
                    "slide:0:256:shape:0",
                    "slide:0:256:shape:8",
                    "slide:0:256:shape:8.13",
                    "slide:1:257:shape:16",
                ]
            );
        }
    }

    #[test]
    fn seeding_stores_hidden_only_for_hidden_shapes() {
        assert!(hidden_keys(&DeckSession::open(FIXTURE, 103).unwrap()).is_empty());

        let session = DeckSession::open(HIDDEN_FIXTURE, 104).unwrap();
        assert_eq!(
            hidden_keys(&session),
            [
                "slide:0:256:shape:0",
                "slide:0:256:shape:8",
                "slide:0:256:shape:8.13",
                "slide:1:257:shape:16",
                "slide:1:257:shape:4",
            ]
        );
        let snapshot = session.snapshot().unwrap();
        let group = &snapshot.slides[0].shapes[8];
        assert!(snapshot.slides[0].shapes[0].hidden);
        assert!(group.hidden);
        assert_eq!(group.children.len(), 14);
        assert!(group.children[..13].iter().all(|child| !child.hidden));
        assert!(group.children[13].hidden);
    }

    #[test]
    fn hidden_flags_serialise_sparsely_and_round_trip() {
        let snapshot = DeckSession::open(HIDDEN_FIXTURE, 106)
            .unwrap()
            .snapshot()
            .unwrap();
        let json = serde_json::to_string(&snapshot).unwrap();
        assert_eq!(json.matches("\"hidden\":true").count(), 5);
        assert!(!json.contains("\"hidden\":false"));
        assert_eq!(
            serde_json::from_str::<DeckSnapshot>(&json).unwrap(),
            snapshot
        );
    }

    fn hidden_keys(session: &DeckSession) -> Vec<String> {
        let txn = session.doc.transact();
        let shapes = required_map(&txn, SHAPES).unwrap();
        let mut ids: Vec<String> = shapes
            .iter(&txn)
            .filter_map(|(id, value)| value.cast::<MapRef>().ok().map(|shape| (id, shape)))
            .filter(|(_, shape)| shape.get(&txn, "hidden").is_some())
            .map(|(id, _)| id.to_owned())
            .collect();
        ids.sort();
        ids
    }

    #[test]
    fn delete_operations_remove_owned_map_entries() {
        let session = DeckSession::open(FIXTURE, 101).unwrap();
        let context = EditCtx::local("test");
        let baseline = map_lengths(&session);

        for cycle in 0..3 {
            let index = session.snapshot().unwrap().slides.len() as u32;
            let slide = session.insert_slide(&context, index, None).unwrap();
            let first = session
                .add_text_box(&context, &slide.slide_id, &draft(cycle, 0))
                .unwrap();
            session
                .add_text_box(&context, &slide.slide_id, &draft(cycle, 1))
                .unwrap();
            assert_eq!(map_lengths(&session), add_lengths(baseline, (1, 2, 2)));

            session
                .remove_shape(&context, &slide.slide_id, &first.shape_id)
                .unwrap();
            assert_eq!(map_lengths(&session), add_lengths(baseline, (1, 1, 1)));

            session.delete_slide(&context, &slide.slide_id).unwrap();
            assert_eq!(map_lengths(&session), baseline);
        }
    }

    #[test]
    fn deleting_seeded_slide_cascades_descendant_entries() {
        let session = DeckSession::open(FIXTURE, 202).unwrap();
        let slide = session.snapshot().unwrap().slides[0].clone();
        let before = map_lengths(&session);
        let owned = slide.shapes.iter().fold((0, 0), |total, shape| {
            let next = shape_entry_lengths(shape);
            (total.0 + next.0, total.1 + next.1)
        });

        session
            .delete_slide(&EditCtx::local("test"), &slide.id)
            .unwrap();

        assert!(owned.0 > slide.shapes.len() as u32);
        assert_eq!(
            map_lengths(&session),
            (before.0 - 1, before.1 - owned.0, before.2 - owned.1)
        );
    }

    fn draft(cycle: u32, index: u32) -> ShapeDraft {
        ShapeDraft {
            name: format!("Shape {cycle}:{index}"),
            rect: ShapeRect {
                x: 100_000,
                y: 100_000,
                width: 1_000_000,
                height: 500_000,
            },
            text: "Text".to_owned(),
            style: TextStyle::default(),
        }
    }

    fn map_lengths(session: &DeckSession) -> (u32, u32, u32) {
        let txn = session.doc.transact();
        (
            required_map(&txn, SLIDES).unwrap().len(&txn),
            required_map(&txn, SHAPES).unwrap().len(&txn),
            required_map(&txn, STORIES).unwrap().len(&txn),
        )
    }

    fn shape_entry_lengths(shape: &ShapeSnapshot) -> (u32, u32) {
        shape.children.iter().fold(
            (1, shape.text_stories.len() as u32),
            |(shape_count, story_count), child| {
                let child_counts = shape_entry_lengths(child);
                (shape_count + child_counts.0, story_count + child_counts.1)
            },
        )
    }

    fn add_lengths(left: (u32, u32, u32), right: (u32, u32, u32)) -> (u32, u32, u32) {
        (left.0 + right.0, left.1 + right.1, left.2 + right.2)
    }

    #[test]
    fn a_v2_comment_snapshot_records_its_flavour_while_deferring_the_import() {
        use std::sync::Mutex;
        use yrs::Update;
        use yrs::updates::decoder::Decode;

        const V2: &[u8] = include_bytes!("../tests/fixtures/deck-schema-v2-comments.update.bin");
        let doc = crate::doc_with_client_id(9620);
        doc.transact_mut()
            .apply_update(Update::decode_v1(V2).unwrap())
            .unwrap();
        let before = {
            let txn = doc.transact();
            let meta = required_map(&txn, META).unwrap();
            assert_eq!(map_number(&meta, &txn, "schemaVersion"), Some(2.0));
            assert!(meta.get(&txn, "commentFlavor").is_none());
            package_from_meta(&meta, &txn).unwrap()
        };
        let observed = Arc::new(Mutex::new(Vec::new()));
        let events = observed.clone();
        let _subscription = doc
            .observe_update_v1(move |txn, _| {
                let meta = required_map(txn, META).unwrap();
                events.lock().unwrap().push((
                    map_number(&meta, txn, "schemaVersion").unwrap(),
                    package_from_meta(&meta, txn).unwrap(),
                    map_string(&meta, txn, "commentFlavor"),
                    map_bool(&meta, txn, "commentsPendingSource"),
                ));
            })
            .unwrap();
        migrate_doc(&doc).unwrap();
        let events = observed.lock().unwrap();
        assert_eq!(
            *events,
            [(
                SCHEMA_VERSION,
                before,
                Some("legacy".to_owned()),
                Some(true)
            )]
        );
    }
}