json_eval_rs/jsoneval/

layout.rs

use super::JSONEval;
use crate::jsoneval::path_utils;
use crate::jsoneval::types::{LayoutOverlayEntry, ResolvedLayoutResult};
use crate::time_block;

use indexmap::IndexMap;
use serde_json::Value;

impl JSONEval {
    /// Resolve layout references, return overlay entries.
    ///
    /// Unlike old version: does NOT mutate evaluated_schema.
    /// Returns list of overlay entries describing delta properties per element.
    ///
    /// # Arguments
    ///
    /// * `evaluate` - If true, runs evaluation before resolving layout.
    pub fn resolve_layout(&mut self, evaluate: bool) -> Result<ResolvedLayoutResult, String> {
        if evaluate {
            let data_str = serde_json::to_string(&self.data)
                .map_err(|e| format!("Failed to serialize data: {}", e))?;
            self.evaluate(&data_str, None, None, None)?;
        }

        Ok(self.resolve_layout_internal())
    }

    fn resolve_layout_internal(&mut self) -> ResolvedLayoutResult {
        time_block!("  resolve_layout_internal()", {
            let layout_paths = self.layout_paths.clone();
            let mut all_entries = ResolvedLayoutResult::new();

            // Resolve every ref from current evaluated_schema. Visibility state remains
            // ephemeral: overlays and hidden indexes never mutate evaluated_schema.
            self.layout_hidden_refs.clear();
            self.layout_visible_refs.clear();
            self.layout_condition_hidden_refs.clear();
            // A nested field layout is expanded by its parent's `$ref` tree. Resolving it
            // again as a standalone root loses its actual parent visibility and would make a
            // shared ref look visible when every real attachment is hidden.
            let attached_layout_refs = Self::collect_layout_ref_targets(&self.schema);
            time_block!("    resolve_layout_elements", {
                for layout_path in layout_paths.iter().filter(|path| {
                    let owner = Self::layout_owner_pointer(path);
                    owner.is_empty() || !attached_layout_refs.contains(&owner)
                }) {
                    let resolved_tree = self.resolve_elements_tree(layout_path);
                    let entries = Self::tree_to_overlays(
                        &resolved_tree,
                        layout_path,
                        false,
                        false,
                        false,
                        &mut self.layout_hidden_refs,
                        &mut self.layout_visible_refs,
                        &mut self.layout_condition_hidden_refs,
                    );
                    all_entries.extend(entries);
                }
            });

            // Schema-wide filtering and clearing apply only if no attached layout occurrence
            // renders this ref visible. Overlay entries above retain per-occurrence state.
            for visible_ref in &self.layout_visible_refs {
                self.layout_hidden_refs.shift_remove(visible_ref);
                self.layout_condition_hidden_refs.shift_remove(visible_ref);
            }

            all_entries
        })
    }

    // ── Phase 1 helpers ─────────────────────────────────────────────

    /// Return schema pointer owning `.../$layout/elements`; root layouts have no owner.
    fn layout_owner_pointer(layout_path: &str) -> String {
        let owner = layout_path
            .trim_end_matches("/$layout/elements")
            .trim_start_matches('#');
        owner.to_string()
    }

    /// Collect schema targets referenced from layout elements only. Formula `$ref`s are
    /// intentionally ignored: they do not attach a field to a visual layout parent.
    fn collect_layout_ref_targets(schema: &Value) -> indexmap::IndexSet<String> {
        fn collect_elements(elements: &Value, refs: &mut indexmap::IndexSet<String>) {
            let Some(elements) = elements.as_array() else {
                return;
            };
            for element in elements {
                let Some(map) = element.as_object() else {
                    continue;
                };
                if let Some(reference) = map.get("$ref").and_then(Value::as_str) {
                    let pointer = path_utils::normalize_to_json_pointer(
                        &path_utils::dot_notation_to_schema_pointer(reference),
                    )
                    .trim_start_matches('#')
                    .to_string();
                    refs.insert(pointer);
                }
                if let Some(children) = map.get("elements") {
                    collect_elements(children, refs);
                }
            }
        }

        fn walk(value: &Value, refs: &mut indexmap::IndexSet<String>) {
            let Some(map) = value.as_object() else {
                return;
            };
            if let Some(elements) = map
                .get("$layout")
                .and_then(Value::as_object)
                .and_then(|layout| layout.get("elements"))
            {
                collect_elements(elements, refs);
            }
            for child in map.values() {
                walk(child, refs);
            }
        }

        let mut refs = indexmap::IndexSet::new();
        walk(schema, &mut refs);
        refs
    }

    /// Resolve $ref in elements tree, return full resolved tree (no parent cascade yet).
    /// Returns Vec<(resolved_element, schema_ref_path)> — one per element at this level.
    fn resolve_elements_tree(&self, layout_elements_path: &str) -> Vec<(Value, String)> {
        let normalized_path = path_utils::normalize_to_json_pointer(layout_elements_path);

        let elements = if let Some(Value::Array(arr)) = self.schema.pointer(&normalized_path) {
            arr.clone()
        } else {
            return Vec::new();
        };

        let mut result = Vec::with_capacity(elements.len());
        for element in elements.into_iter() {
            let (resolved, schema_ref) = self.resolve_element_ref_recursive(element, "");
            result.push((resolved, schema_ref));
        }
        result
    }

    /// Resolve an element's $ref recursively, returning (resolved_element, schema_ref_path).
    /// schema_ref_path is the outermost $ref target (empty if no $ref).
    ///
    /// The resolved element is a "full tree" — $ref expanded, metadata injected,
    /// nested elements arrays also resolved. Used for parent condition cascade.
    fn resolve_element_ref_recursive(
        &self,
        element: Value,
        _path_context: &str,
    ) -> (Value, String) {
        // Resolve this element's $ref
        let (mut resolved, ref_path) = self.resolve_element_ref(element);

        // Recursively resolve nested elements
        if let Value::Object(ref mut map) = resolved {
            if let Some(Value::Array(elements)) = map.get("elements").cloned() {
                let mut resolved_nested = Vec::with_capacity(elements.len());
                for nested_element in elements.into_iter() {
                    let (nested_resolved, _) =
                        self.resolve_element_ref_recursive(nested_element, "");
                    resolved_nested.push(nested_resolved);
                }
                map.insert("elements".to_string(), Value::Array(resolved_nested));
            }
        }

        (resolved, ref_path)
    }

    /// Resolve $ref in a single element. Returns (resolved_element, schema_ref_path).
    /// Does NOT recurse into nested elements.
    fn resolve_element_ref(&self, element: Value) -> (Value, String) {
        match element {
            Value::Object(mut map) => {
                let has_ref = map.get("$ref").is_some();
                let ref_path = if has_ref {
                    map.get("$ref")
                        .and_then(Value::as_str)
                        .unwrap_or("")
                        .to_string()
                } else {
                    String::new()
                };

                if let Some(Value::String(ref_str)) = map.get("$ref").cloned() {
                    // Resolve the $ref to an actual schema pointer first
                    let normalized_path = if ref_str.starts_with('#') || ref_str.starts_with('/') {
                        path_utils::normalize_to_json_pointer(&ref_str).into_owned()
                    } else {
                        let schema_pointer = path_utils::dot_notation_to_schema_pointer(&ref_str);
                        let schema_path =
                            path_utils::normalize_to_json_pointer(&schema_pointer).into_owned();

                        if self.evaluated_schema.pointer(&schema_path).is_some() {
                            schema_path
                        } else {
                            format!("/properties/{}", ref_str.replace('.', "/properties/"))
                        }
                    };

                    // Build $fullpath from the actual resolved pointer (not the raw $ref string).
                    // This ensures $fullpath always reflects the true schema field path.
                    let dotted_path = path_utils::pointer_to_dot_notation(&normalized_path);
                    let last_segment = dotted_path.split('.').last().unwrap_or(&dotted_path);

                    map.insert("$fullpath".to_string(), Value::String(dotted_path.clone()));
                    map.insert("$path".to_string(), Value::String(last_segment.to_string()));
                    map.insert("$parentHide".to_string(), Value::Bool(false));

                    if let Some(referenced_value) = self.evaluated_schema.pointer(&normalized_path)
                    {
                        let resolved = referenced_value.clone();

                        if let Value::Object(mut resolved_map) = resolved {
                            map.remove("$ref");

                            if let Some(Value::Object(layout_obj)) = resolved_map.remove("$layout")
                            {
                                let mut result = layout_obj.clone();
                                for (key, value) in resolved_map {
                                    if key != "type" || !result.contains_key("type") {
                                        result.insert(key, value);
                                    }
                                }
                                // Ensure $fullpath from the map (actual ref path) wins
                                for (key, value) in map {
                                    result.insert(key, value);
                                }
                                return (Value::Object(result), dotted_path);
                            } else {
                                for (key, value) in map {
                                    resolved_map.insert(key, value);
                                }
                                return (Value::Object(resolved_map), dotted_path);
                            }
                        } else {
                            return (resolved, dotted_path);
                        }
                    }
                }

                (Value::Object(map), ref_path)
            }
            _ => (element, String::new()),
        }
    }

    /// Convert a resolved elements tree into flat overlay entries with parent condition cascade.
    ///
    /// Walks the tree recursively. At each level:
    ///   1. Determine parent state (hidden/disabled propagated from above)
    ///   2. Merge element's own condition with inherited state
    ///   3. Emit one LayoutOverlayEntry per element with full overlay delta
    ///
    /// The `base_ref_path` is the parent's `schema_ref_path` (empty for root).
    fn tree_to_overlays(
        tree: &[(Value, String)],
        layout_path: &str,
        parent_hidden: bool,
        parent_condition_hidden: bool,
        parent_disabled: bool,
        layout_hidden_refs: &mut indexmap::IndexSet<String>,
        layout_visible_refs: &mut indexmap::IndexSet<String>,
        layout_condition_hidden_refs: &mut indexmap::IndexSet<String>,
    ) -> ResolvedLayoutResult {
        let mut entries = ResolvedLayoutResult::new();

        for (idx, (element, ref_path)) in tree.iter().enumerate() {
            let element_idx = idx;
            let mut overlay = IndexMap::new();

            // ── Build thin overlay: only delta props (skip structural keys) ──
            if let Value::Object(map) = element {
                // Keys that should NOT appear in overlay:
                // - $ref: handled by compact schema
                // - elements: handled by child overlays
                // - properties/items/required: schema structure, not layout
                const EXCLUDED: &[&str] = &[
                    "$ref",
                    "elements",
                    "properties",
                    "items",
                    "required",
                    "additionalProperties",
                ];
                for (key, value) in map {
                    if !EXCLUDED.contains(&key.as_str()) {
                        overlay.insert(key.clone(), value.clone());
                    }
                }

                // ── Inject $fullpath for ALL elements (ref and non-ref) ──
                if !overlay.contains_key("$fullpath") {
                    if !ref_path.is_empty() {
                        // $ref element: use the actual schema ref target dotted path
                        let last_segment = ref_path.split('.').last().unwrap_or(ref_path);
                        overlay.insert("$fullpath".to_string(), Value::String(ref_path.clone()));
                        overlay
                            .insert("$path".to_string(), Value::String(last_segment.to_string()));
                    } else {
                        // Non-$ref (inline layout container): retain its literal structural
                        // schema path so callers can identify its exact layout position.
                        //
                        // e.g. "#/illustration/$layout/elements" → "illustration.$layout.elements.1"
                        let base = Self::layout_path_to_structural_path(layout_path);
                        let fullpath = if base.is_empty() {
                            format!("{}", element_idx)
                        } else {
                            format!("{}.{}", base, element_idx)
                        };
                        let last_segment =
                            fullpath.split('.').last().unwrap_or(&fullpath).to_string();
                        overlay.insert("$fullpath".to_string(), Value::String(fullpath));
                        overlay.insert("$path".to_string(), Value::String(last_segment));
                    }
                }

                // Override $parentHide — may exist from ref resolution as false,
                // but tree_to_overlays owns the correct parent_hidden value.
                overlay.insert("$parentHide".to_string(), Value::Bool(parent_hidden));

                // ── Parent condition cascade ──
                let mut element_hidden = parent_hidden;
                let mut element_condition_hidden = parent_condition_hidden;
                let mut element_disabled = parent_disabled;

                // Element's own condition (from overlay now)
                if let Some(Value::Object(cond)) = overlay.get("condition") {
                    if let Some(Value::Bool(true)) = cond.get("hidden") {
                        element_hidden = true;
                        element_condition_hidden = true;
                    }
                    if let Some(Value::Bool(d)) = cond.get("disabled") {
                        element_disabled = element_disabled || *d;
                    }
                }

                // hideLayout affects presentation/output visibility, but not data-clearing policy.
                if let Some(Value::Object(hide)) = overlay.get("hideLayout") {
                    if let Some(Value::Bool(true)) = hide.get("all") {
                        element_hidden = true;
                    }
                }

                if !ref_path.is_empty() {
                    let pointer = path_utils::normalize_to_json_pointer(
                        &path_utils::dot_notation_to_schema_pointer(ref_path),
                    )
                    .trim_start_matches('#')
                    .to_string();
                    if element_hidden {
                        layout_hidden_refs.insert(pointer.clone());
                        if element_condition_hidden {
                            layout_condition_hidden_refs.insert(pointer);
                        }
                    } else {
                        layout_visible_refs.insert(pointer);
                    }
                }

                // Only show condition cascade if parent has state OR element has state
                let show_condition_cascade =
                    parent_hidden || parent_disabled || element_hidden || element_disabled;

                // $parentHide already set above

                // ── Condition cascade: if parent OR element has state, emit merged condition ──
                if show_condition_cascade {
                    let mut merged_cond = serde_json::Map::new();
                    if let Some(Value::Object(existing)) = overlay.get("condition") {
                        for (k, v) in existing.iter() {
                            merged_cond.insert(k.clone(), v.clone());
                        }
                    }
                    // Merge in hidden states from parent and element
                    if parent_hidden || element_hidden {
                        merged_cond.insert("hidden".to_string(), Value::Bool(true));
                    }
                    if parent_disabled || element_disabled {
                        merged_cond.insert("disabled".to_string(), Value::Bool(true));
                    }
                    overlay.insert("condition".to_string(), Value::Object(merged_cond));

                    // Also push hideLayout cascade for layout containers
                    if (parent_hidden || element_hidden)
                        && (element.get("hideLayout").is_some() || element.get("type").is_some())
                    {
                        let mut hide_layout =
                            if let Some(Value::Object(h)) = element.get("hideLayout") {
                                h.clone()
                            } else {
                                serde_json::Map::new()
                            };
                        hide_layout.insert("all".to_string(), Value::Bool(true));
                        overlay.insert("hideLayout".to_string(), Value::Object(hide_layout));
                    }
                }

                // ── Recurse into nested elements ──
                if let Some(Value::Array(children)) = element.get("elements") {
                    // Build nested tree from children
                    let child_tree: Vec<(Value, String)> = children
                        .iter()
                        .map(|c| {
                            if let Value::Object(m) = c {
                                (
                                    c.clone(),
                                    m.get("$fullpath")
                                        .and_then(Value::as_str)
                                        .unwrap_or("")
                                        .to_string(),
                                )
                            } else {
                                (c.clone(), String::new())
                            }
                        })
                        .collect();

                    let child_layout_path = format!(
                        "{}/{}/elements",
                        layout_path.trim_end_matches('/'),
                        element_idx
                    );

                    // Recurse into children with element_hidden/element_disabled as parent state
                    let child_overlays = Self::tree_to_overlays(
                        &child_tree,
                        &child_layout_path,
                        element_hidden,
                        element_condition_hidden,
                        element_disabled,
                        layout_hidden_refs,
                        layout_visible_refs,
                        layout_condition_hidden_refs,
                    );
                    entries.extend(child_overlays);
                }
            }

            entries.push(LayoutOverlayEntry {
                layout_path: layout_path.to_string(),
                element_idx,
                schema_ref_path: ref_path.clone(),
                overlay,
            });
        }

        entries
    }

    // ── Private helpers ──────────────────────────────────────────────────────

    /// Convert a layout elements pointer to its literal dotted structural path.
    ///
    /// ## Examples
    ///
    /// ```text
    /// "#/illustration/$layout/elements" → "illustration.$layout.elements"
    /// "#/properties/form/$layout/elements" → "properties.form.$layout.elements"
    /// ```
    fn layout_path_to_structural_path(layout_path: &str) -> String {
        layout_path
            .trim_start_matches('#')
            .trim_start_matches('/')
            .split('/')
            .filter(|segment| !segment.is_empty())
            .collect::<Vec<_>>()
            .join(".")
    }
}