tablo-core 0.8.0

//! The choice control: a `<select>` over static options or a relationship's rows, with an optional
//! filter input, or a listed input per option: a radio, a checkbox when the choice takes several,
//! or either drawn as a button.

use tablo_ui::{input as ui_input, select as ui_select};
use toasty::stmt::Expr;
use topcoat::{Result, context::Cx, view::*};

use super::{
    super::relationship::{OptionLoadError, RelatedCheck},
    Field, Placement, render_field,
};
use crate::values::FormValue;

mod check;
mod listed;
mod relationship;

pub(crate) use listed::Layout;
pub(crate) use relationship::Relationship;

/// What a choice field declares beyond presence.
#[derive(Clone, Default)]
pub(crate) struct ChoiceControl {
    pub(super) searchable: bool,
    /// Whether this is an embedded enum's variant control.
    pub(super) discriminant: bool,
    /// Static `(value, label)` options.
    pub(super) options: Vec<(String, crate::Text)>,
    pub(super) relationship: Option<Relationship>,
    /// The field whose value narrows the relationship's rows, set by `depends_on`.
    pub(super) parent: Option<Parent>,
    /// Whether the choice takes several options, set by `multiple`: its key then holds a list.
    pub(super) multiple: bool,
    /// How many options a multiple choice takes, set by `min_items` and `max_items`.
    pub(super) bounds: super::Items,
    /// How the options render, set by `radio` and `buttons`.
    pub(super) layout: Layout,
}

/// What narrows a dependent choice's options: the related rows whose column equals the value the
/// field `watched` posts.
#[derive(Clone)]
pub(crate) struct Parent {
    pub(super) watched: String,
    /// The model the column belongs to, which must be the relationship's source model.
    pub(super) model: std::any::TypeId,
    /// The name of the field the column is, when it names one.
    pub(super) column: Option<String>,
    /// The predicate selecting the rows for a trimmed, non-empty parent value, or `None` when the
    /// column's type does not parse it.
    pub(super) scope: ParentScope,
}

/// A dependent choice's predicate for one parent value.
pub(crate) type ParentScope = std::sync::Arc<dyn Fn(&str) -> Option<Expr<bool>> + Send + Sync>;

/// The rows a dependent choice offers for one parent value.
enum Scope {
    /// Not a dependent choice: every row.
    All,
    /// The rows the predicate selects.
    Within(Expr<bool>),
    /// A blank parent, or one the column does not parse: no row.
    Nothing,
}

/// One `<option>` with its value and label.
pub(crate) fn option_view<'a>(
    cx: &'a Cx,
    value: String,
    label: String,
    selected: bool,
) -> BoxView<'a> {
    view! { cx => <option value=(value) selected=(selected)>(label)</option> }.boxed()
}

impl ChoiceControl {
    pub(crate) fn is_searchable(&self) -> bool {
        self.searchable
    }

    /// The label of the static option storing `value`.
    pub(crate) fn label_of(&self, value: &str) -> Option<&crate::Text> {
        self.options
            .iter()
            .find(|(stored, _)| stored == value)
            .map(|(_, label)| label)
    }

    /// The static options with their labels in the request's locale.
    fn spelled(&self, cx: &Cx) -> Vec<(String, String)> {
        self.options
            .iter()
            .map(|(value, label)| (value.clone(), label.localize(cx)))
            .collect()
    }

    /// Whether the choice declares neither options nor a relationship: its `<select>` offers
    /// nothing, and validation, with no option to check against, would accept any value.
    pub(crate) fn offers_nothing(&self) -> bool {
        self.options.is_empty() && self.relationship.is_none()
    }

    pub(crate) fn is_relationship(&self) -> bool {
        self.relationship.is_some()
    }

    /// Whether the choice takes several options.
    pub(crate) fn is_multiple(&self) -> bool {
        self.multiple
    }

    /// Whether the choice renders an input per option rather than a `<select>`: the browser
    /// cannot fetch its options again, so it cannot depend on another field.
    pub(crate) fn is_listed(&self) -> bool {
        self.multiple || self.layout != Layout::Select
    }

    /// The relationship's source model in the app schema.
    pub(crate) fn source_model(&self) -> Option<crate::toasty_compat::model::ModelId> {
        self.relationship
            .as_ref()
            .map(|relationship| relationship.model_id)
    }

    /// The source model's name when the choice's options show records under a label a panel
    /// cannot mask: see [`Relationship::unmasked_model`](super::choice::Relationship).
    pub(crate) fn unmasked_model(
        &self,
        is_mounted: impl Fn(std::any::TypeId) -> bool,
        restricted: impl Fn(crate::toasty_compat::model::ModelId) -> bool,
    ) -> Option<&'static str> {
        self.relationship
            .as_ref()?
            .unmasked_model(is_mounted, restricted)
    }

    /// The field a dependent choice narrows its options by, when `restricts` says a mounted
    /// resource restricts it of the source model: the options would then show which records hold
    /// each value of it.
    pub(crate) fn narrowed_by(
        &self,
        restricts: impl Fn(crate::toasty_compat::model::ModelId, &str) -> bool,
    ) -> Option<&str> {
        let column = self.parent.as_ref()?.column.as_deref()?;
        let model = self.relationship.as_ref()?.model_id;
        restricts(model, column).then_some(column)
    }

    /// The key of the field whose value narrows a dependent choice's options.
    pub(crate) fn parent_key(&self) -> Option<&str> {
        self.parent.as_ref().map(|parent| parent.watched.as_str())
    }

    /// Whether `depends_on` names a column of another model than the relationship's source, or
    /// the choice has no relationship to narrow.
    pub(crate) fn misdeclared_parent(&self) -> bool {
        self.parent.as_ref().is_some_and(|parent| {
            self.relationship
                .as_ref()
                .is_none_or(|relationship| relationship.model != parent.model)
        })
    }

    /// The rows the choice offers while its parent posts `parent`.
    fn scope(&self, parent: Option<&str>) -> Scope {
        let Some(declared) = &self.parent else {
            return Scope::All;
        };
        let value = parent.unwrap_or("").trim();
        if value.is_empty() {
            return Scope::Nothing;
        }
        match (declared.scope)(value) {
            Some(expr) => Scope::Within(expr),
            None => Scope::Nothing,
        }
    }

    /// Whether the options come from a model with a composite primary key.
    pub(crate) fn has_composite_source(&self) -> bool {
        self.relationship
            .as_ref()
            .is_some_and(|relationship| relationship.composite)
    }

    /// The model the options come from, when its rows are tenant-owned.
    pub(crate) fn tenant_scoped_model(
        &self,
        cx: &Cx,
    ) -> Option<crate::toasty_compat::model::ModelId> {
        self.relationship
            .as_ref()
            .and_then(|relationship| (relationship.tenant_scoped_model)(cx))
    }

    /// The option source's type when the request's panel cannot load from it.
    pub(crate) fn unavailable_source(&self, cx: &Cx) -> Option<&'static str> {
        self.relationship
            .as_ref()
            .and_then(|relationship| relationship.unavailable_source(cx))
    }

    /// Searches options server-side among those the parent value `parent` offers, answering
    /// `Overflow` past the option cap.
    pub(crate) async fn search_options(
        &self,
        cx: &Cx,
        q: &str,
        parent: Option<&str>,
    ) -> Result<Vec<(String, String)>, OptionLoadError> {
        let Some(relationship) = &self.relationship else {
            return Ok(self.spelled(cx));
        };
        match self.scope(parent) {
            Scope::All => (relationship.search)(cx, q.to_string(), None).await,
            Scope::Within(scope) => (relationship.search)(cx, q.to_string(), Some(scope)).await,
            Scope::Nothing => Ok(Vec::new()),
        }
    }

    /// The options the choice offers while its parent posts `parent`: a dependent choice's bounded
    /// head of the rows its parent selects.
    async fn load_options(
        &self,
        cx: &Cx,
        parent: Option<&str>,
    ) -> Result<Vec<(String, String)>, OptionLoadError> {
        match (&self.relationship, self.scope(parent)) {
            (Some(relationship), Scope::All) => (relationship.load)(cx).await,
            (Some(relationship), Scope::Within(scope)) => {
                (relationship.search)(cx, String::new(), Some(scope)).await
            }
            (Some(_), Scope::Nothing) => Ok(Vec::new()),
            (None, _) => Ok(self.spelled(cx)),
        }
    }

    /// `value`, a multiple choice's list, with each key of the stored list `stored` it drops that
    /// the user cannot view in the request's tenant put back: a submission unlinks only the
    /// records its form could offer.
    pub(super) async fn keep_unseen(
        &self,
        cx: &Cx,
        value: &FormValue,
        stored: &FormValue,
        ex: &mut dyn toasty::Executor,
    ) -> Option<FormValue> {
        let relationship = self.relationship.as_ref().filter(|_| self.multiple)?;
        let mut keys = value.as_list()?.to_vec();
        let dropped: Vec<String> = stored
            .as_list()?
            .iter()
            .filter(|key| !keys.contains(key))
            .cloned()
            .collect();
        let before = keys.len();
        for key in dropped {
            // A failed check keeps the link: only a record the user may view is unlinked.
            let seen = matches!(
                (relationship.check)(cx, key.clone(), None, &mut *ex).await,
                Ok(RelatedCheck::FoundViewable)
            );
            if !seen {
                keys.push(key);
            }
        }
        (keys.len() != before).then_some(FormValue::List(keys))
    }
}

impl Field {
    /// Renders a choice field's select with the DOM id `id`, offering what its parent's value
    /// selects.
    pub(super) async fn render_choice<'a>(
        &self,
        choice: &ChoiceControl,
        cx: &'a Cx,
        value: Option<&FormValue>,
        error: Option<&crate::values::FieldError>,
        id: String,
        placement: Placement<'_>,
    ) -> Result<BoxView<'a>> {
        let disabled = self.is_disabled_at(&placement);
        if choice.multiple {
            let chosen = value.and_then(FormValue::as_list).unwrap_or_default();
            return self
                .render_choices(choice, cx, chosen, error, id, disabled)
                .await;
        }
        if choice.is_listed() {
            let chosen: Vec<String> = value
                .and_then(FormValue::as_text)
                .map(str::trim)
                .filter(|chosen| !chosen.is_empty())
                .map(str::to_string)
                .into_iter()
                .collect();
            return self
                .render_choices(choice, cx, &chosen, error, id, disabled)
                .await;
        }
        let value = value.and_then(FormValue::as_text);
        let parent = placement.parent;
        let name = self.name().to_string();
        let required = self.required && !disabled;
        let searchable = choice.searchable;
        let current = value.unwrap_or("").trim().to_string();
        let loaded = choice.load_options(cx, parent).await;
        // A denial hides the stored label and fails closed.
        // A failed load keeps the stored key selectable.
        let denied = matches!(&loaded, Err(OptionLoadError::Denied));
        let overflowed = matches!(&loaded, Err(OptionLoadError::Overflow));
        let overflow_searchable = overflowed && searchable && choice.is_relationship();
        let keep_current_value = matches!(
            &loaded,
            Err(OptionLoadError::LoadFailed)
                | Err(OptionLoadError::Overflow)
                | Err(OptionLoadError::Misdeclared)
        );
        let mut options = loaded.unwrap_or_default();
        if keep_current_value && !current.is_empty() && !options.iter().any(|(v, _)| v == &current)
        {
            options.push((current.clone(), current.clone()));
        }
        let chrome = self.chrome(
            cx,
            id.clone(),
            error,
            denied.then(|| {
                crate::t!(
                    cx,
                    "tablo-field-unavailable",
                    label = self.label().to_owned()
                )
            }),
        );
        let mut option_views: Vec<BoxView<'a>> = vec![option_view(
            cx,
            String::new(),
            crate::t!(cx, "tablo-field-select"),
            current.is_empty(),
        )];
        for (val, lab) in &options {
            option_views.push(option_view(cx, val.clone(), lab.clone(), current == *val));
        }
        let list_id = format!("{id}-options-list");
        let filter_label = crate::t!(
            cx,
            "tablo-field-filter-options",
            label = self.label().to_owned()
        );
        // A dependent choice fetches its options again when its parent changes, and a searchable
        // one fetches as the user types past the cap.
        let dependent = choice.parent_key().map(str::to_string);
        let parent_value = dependent
            .as_ref()
            .map(|_| parent.unwrap_or("").trim().to_string());
        let options_field = (overflow_searchable || dependent.is_some()).then(|| name.clone());
        let options_server = overflow_searchable.then_some("true");
        let options_url = options_field
            .as_ref()
            .and(placement.options)
            .map(str::to_string);
        let overflow_hint = crate::t!(cx, "tablo-field-too-many-options");
        // A searchable dependent choice may overflow after its parent changes, so it always
        // renders the hint, hidden until then.
        let hint = overflow_searchable || (searchable && choice.parent_key().is_some());
        let hint_hidden = !overflow_searchable;
        let aria_invalid = chrome.aria_invalid();
        let described_by = chrome.described_by();
        let control = view! {
            cx =>
            if searchable {
                <div class="relative" data-options-combobox="">
                    ui_input(
                        attrs: attributes! {
                            type="search"
                            role="combobox"
                            aria-expanded="false"
                            aria-controls=(list_id.clone())
                            aria-autocomplete="list"
                            aria-label=(filter_label.clone())
                            placeholder=(crate::t!(cx, "tablo-field-filter"))
                            data-options-filter=""
                            class="h-9"
                            autocomplete="off"
                            disabled=(disabled)
                        }
                    )
                    <ul
                        id=(list_id.clone())
                        data-options-list=""
                        role="listbox"
                        aria-label=(filter_label.clone())
                        hidden=""
                        class="absolute z-20 mt-1 max-h-60 w-full overflow-y-auto rounded-lg border border-border bg-popover p-1 text-sm text-popover-foreground shadow-sm"
                    ></ul>
                </div>
            }
            if hint {
                <div
                    class="text-xs text-muted-foreground"
                    data-options-hint=""
                    hidden=(hint_hidden)
                >
                    (overflow_hint)
                </div>
            }
            ui_select(
                attrs: attributes! {
                    id=(id)
                    name=(name.clone())
                    required=(required)
                    disabled=(disabled)
                    aria-required=(required.then_some("true"))
                    aria-invalid=(aria_invalid)
                    aria-describedby=(described_by)
                },
                for opt in option_views {
                    (opt)
                }
            )
        }
        .boxed();
        render_field(
            cx,
            &chrome,
            &self.label(),
            required,
            attributes! {
                cx =>
                data-select-filterable=""
                data-options-field=(options_field)
                data-options-url=(options_url)
                data-options-server=(options_server)
                data-options-parent=(dependent)
                data-options-parent-value=(parent_value)
                data-options-empty-text=(crate::t!(cx, "tablo-field-no-options"))
                data-options-unmatched-text=(crate::t!(
                    cx,
                    "tablo-field-no-matching-options",
                ))
                data-options-searching-text=(crate::t!(cx, "tablo-field-searching"))
            },
            control,
        )
    }
}

#[cfg(test)]
mod tests;