/**
 * Interface for managing a character's armor calculation.
 * @extends {DocumentSheet}
 */
export default class ActorArmorConfig extends DocumentSheet {
    /** @inheritdoc */
    static get defaultOptions() {
        return foundry.utils.mergeObject(super.defaultOptions, {
            id: "actor-armor-config",
            classes: ["sw5e", "actor-armor-config"],
            template: "systems/sw5e/templates/apps/actor-armor.html",
            width: 320,
            height: "auto"
        });
    }

    /* -------------------------------------------- */

    /** @inheritdoc */
    get title() {
        return `${game.i18n.localize("SW5E.ArmorConfig")}: ${this.document.name}`;
    }

    /* -------------------------------------------- */

    /** @inheritdoc */
    async getData() {
        // Get actor AC data
        const actorData = foundry.utils.deepClone(this.object.data.data);
        const ac = foundry.utils.getProperty(actorData, "attributes.ac");

        // Get configuration data for the calculation mode
        let cfg = CONFIG.SW5E.armorClasses[ac.calc];
        if (!cfg) {
            ac.calc = "flat";
            cfg = CONFIG.SW5E.armorClasses.flat;
        }

        // Return context data
        return {
            ac: ac,
            calculations: CONFIG.SW5E.armorClasses,
            value: this.object._computeArmorClass(actorData).value,
            valueDisabled: !["flat", "natural"].includes(ac.calc),
            formula: ac.calc === "custom" ? ac.formula : cfg.formula,
            formulaDisabled: ac.calc !== "custom"
        };
    }

    /* -------------------------------------------- */

    /** @inheritdoc */
    async _updateObject(event, formData) {
        const ac = foundry.utils.expandObject(formData).ac;
        return this.object.update({"data.attributes.ac": ac});
    }

    /* -------------------------------------------- */
    /*  Event Listeners and Handlers                */
    /* -------------------------------------------- */

    /** @inheritdoc */
    async _onChangeInput(event) {
        await super._onChangeInput(event);

        // Reference actor data
        let actorData = this.object.toObject(false);
        let ac = actorData.data.attributes.ac;

        // Reference form data
        const calc = this.form["ac.calc"].value;
        const cfg = CONFIG.SW5E.armorClasses[calc];
        const enableFlat = ["flat", "natural"].includes(calc);

        // Handle changes to the calculation mode specifically
        let formula = this.form["ac.formula"].value;
        let flat = this.form["ac.flat"].value;
        if (event.currentTarget.name === "ac.calc") {
            formula = calc === "custom" ? ac.formula : cfg.formula;
            if (enableFlat) flat = ac.flat;
        }

        // Recompute effective AC
        actorData = foundry.utils.mergeObject(actorData, {"data.attributes.ac": {calc, formula}});
        if (enableFlat) actorData.data.attributes.ac.flat = flat;
        ac = this.object._computeArmorClass(actorData.data);

        // Update fields
        this.form["ac.formula"].value = ac.formula;
        this.form["ac.formula"].disabled = calc !== "custom";
        this.form["ac.flat"].value = enableFlat ? ac.flat : ac.value;
        this.form["ac.flat"].disabled = !enableFlat;
    }
}