import { ModifiableData } from "../common/common-data";
import { DS4 } from "../config";
import { DS4Item } from "../item/item";
import { DS4Armor, DS4EquippableItemDataType, DS4ItemDataType, DS4Shield, ItemType } from "../item/item-data";
import { DS4ActorDataType } from "./actor-data";

type DS4ActiveEffect = ActiveEffect<DS4ActorDataType, DS4ItemDataType, DS4Actor, DS4Item>;

export class DS4Actor extends Actor<DS4ActorDataType, DS4ItemDataType, DS4Item> {
    /** @override */
    prepareData(): void {
        this.data = duplicate(this._data);
        if (!this.data.img) this.data.img = CONST.DEFAULT_TOKEN;
        if (!this.data.name) this.data.name = "New " + this.entity;
        this.prepareBaseData();
        this.prepareEmbeddedEntities();
        this.applyActiveEffectsToNonDerivedData();
        this.prepareDerivedData();
        this.applyActiveEffectsToDerivedData();
    }

    /** @override */
    prepareBaseData(): void {
        const data = this.data;
        const attributes = data.data.attributes;
        Object.values(attributes).forEach(
            (attribute: ModifiableData<number>) => (attribute.total = attribute.base + attribute.mod),
        );

        const traits = data.data.traits;
        Object.values(traits).forEach((trait: ModifiableData<number>) => (trait.total = trait.base + trait.mod));
    }

    applyActiveEffectsToNonDerivedData(): void {
        this.applyActiveEffectsFiltered((change) => !this.derivedDataProperties.includes(change.key));
    }

    applyActiveEffectsToDerivedData(): void {
        this.applyActiveEffectsFiltered((change) => this.derivedDataProperties.includes(change.key));
    }

    /**
     * Apply ActiveEffectChanges to the Actor data which are caused by ActiveEffects and satisfy the given predicate.
     *
     * @param predicate The predicate that ActiveEffectChanges need to satisfy in order to be applied
     */
    applyActiveEffectsFiltered(predicate: (change: ActiveEffectChange) => boolean): void {
        const overrides = {};

        // Organize non-disabled effects by their application priority
        const changes = this.effects.reduce((changes: Array<ActiveEffectChange & { effect: DS4ActiveEffect }>, e) => {
            if (e.data.disabled) return changes;

            return changes.concat(
                e.data.changes.filter(predicate).map((c) => {
                    c = duplicate(c);
                    c.priority = c.priority ?? c.mode * 10;
                    return { ...c, effect: e };
                }),
            );
        }, []);
        changes.sort((a, b) => a.priority - b.priority);

        // Apply all changes
        for (const change of changes) {
            const result = change.effect.apply(this, change);
            if (result !== null) overrides[change.key] = result;
        }

        // Expand the set of final overrides
        this["overrides"] = expandObject({ ...flattenObject(this["overrides"] ?? {}), ...overrides });
    }

    /** @override */
    prepareDerivedData(): void {
        this._prepareCombatValues();
    }

    /** The list of properties that are derived from others, given in dot notation */
    get derivedDataProperties(): Array<string> {
        return Object.keys(DS4.combatValues)
            .map((combatValue) => `data.combatValues.${combatValue}.total`)
            .concat("data.combatValues.hitPoints.max");
    }

    /**
     * The list of item types that can be owned by this actor.
     */
    get ownableItemTypes(): Array<ItemType> {
        switch (this.data.type) {
            case "character":
                return [
                    "weapon",
                    "armor",
                    "shield",
                    "trinket",
                    "equipment",
                    "spell",
                    "talent",
                    "racialAbility",
                    "language",
                    "alphabet",
                ];
            case "creature":
                return ["weapon", "armor", "shield", "trinket", "equipment", "spell", "specialCreatureAbility"];
            default:
                return [];
        }
    }

    /**
     * Checks whether or not the given item type can be owned by the actor.
     * @param itemType the item type to check
     */
    canOwnItemType(itemType: ItemType): boolean {
        return this.ownableItemTypes.includes(itemType);
    }

    /**
     *  Prepares the combat values of the actor.
     */
    private _prepareCombatValues(): void {
        const data = this.data.data;
        const armorValueOfEquippedItems = this._calculateArmorValueOfEquippedItems();
        data.combatValues.hitPoints.base =
            (data.attributes.body.total ?? 0) + (data.traits.constitution.total ?? 0) + 10;

        data.combatValues.defense.base =
            (data.attributes.body.total ?? 0) + (data.traits.constitution.total ?? 0) + armorValueOfEquippedItems;
        data.combatValues.initiative.base = (data.attributes.mobility.total ?? 0) + (data.traits.agility.total ?? 0);
        data.combatValues.movement.base = (data.attributes.mobility.total ?? 0) / 2 + 1;
        data.combatValues.meleeAttack.base = (data.attributes.body.total ?? 0) + (data.traits.strength.total ?? 0);
        data.combatValues.rangedAttack.base =
            (data.attributes.mobility.total ?? 0) + (data.traits.dexterity.total ?? 0);
        data.combatValues.spellcasting.base =
            (data.attributes.mind.total ?? 0) + (data.traits.aura.total ?? 0) - armorValueOfEquippedItems;
        data.combatValues.targetedSpellcasting.base =
            (data.attributes.mind.total ?? 0) + (data.traits.dexterity.total ?? 0) - armorValueOfEquippedItems;

        Object.values(data.combatValues).forEach(
            (combatValue: ModifiableData<number>) => (combatValue.total = combatValue.base + combatValue.mod),
        );

        data.combatValues.hitPoints.max = data.combatValues.hitPoints.total;
    }

    /**
     * Calculates the total armor value of all equipped items.
     */
    private _calculateArmorValueOfEquippedItems(): number {
        return this.items
            .filter((item) => ["armor", "shield"].includes(item.type))
            .map((item) => item.data.data as DS4Armor | DS4Shield)
            .filter((itemData) => itemData.equipped)
            .map((itemData) => itemData.armorValue)
            .reduce((a, b) => a + b, 0);
    }

    /**
     * Handle how changes to a Token attribute bar are applied to the Actor.
     * This only differs from the base implementation by also allowing negative values.
     * @override
     */
    async modifyTokenAttribute(attribute: string, value: number, isDelta = false, isBar = true): Promise<DS4Actor> {
        const current = getProperty(this.data.data, attribute);

        // Determine the updates to make to the actor data
        let updates: Record<string, number>;
        if (isBar) {
            if (isDelta) value = Math.min(Number(current.value) + value, current.max);
            updates = { [`data.${attribute}.value`]: value };
        } else {
            if (isDelta) value = Number(current) + value;
            updates = { [`data.${attribute}`]: value };
        }

        // Call a hook to handle token resource bar updates
        const allowed = Hooks.call("modifyTokenAttribute", { attribute, value, isDelta, isBar }, updates);
        return allowed !== false ? this.update(updates) : this;
    }

    /** @override */
    createEmbeddedEntity(
        embeddedName: string,
        createData: Record<string, unknown> | Array<Record<string, unknown>>,
        options?: Record<string, unknown>,
    ): Promise<this> {
        if (embeddedName === "OwnedItem") {
            this._preCreateOwnedItem((createData as unknown) as ItemData<DS4ItemDataType>);
        }
        return super.createEmbeddedEntity(embeddedName, createData, options);
    }

    /**
     * If the item that is going to be created is equippable, set it to be non equipped and disable all ActiveEffects
     * contained in the item
     * @param itemData The data of the item to be created
     */
    private _preCreateOwnedItem(itemData: ItemData<DS4ItemDataType>): void {
        if ("equipped" in itemData.data) {
            itemData.effects = itemData.effects.map((effect) => ({ ...effect, disabled: true }));
            const equippableUpdateData = itemData as ItemData<DS4EquippableItemDataType>;
            equippableUpdateData.data.equipped = false;
        }
    }

    /** @override */
    updateEmbeddedEntity(
        embeddedName: string,
        updateData: Record<string, unknown> | Array<Record<string, unknown>>,
        options?: Record<string, unknown>,
    ): Promise<this> {
        if (embeddedName === "OwnedItem") {
            this._preUpdateOwnedItem(updateData as Partial<ItemData<DS4ItemDataType>>);
        }
        return super.updateEmbeddedEntity(embeddedName, updateData, options);
    }

    /**
     * If the equipped flag of an item changed, update all ActiveEffects originating from that item accordingly.
     * @param updateData The change that is going to be applied to the owned item
     */
    private _preUpdateOwnedItem(updateData: Partial<ItemData<DS4ItemDataType>>): void {
        if ("equipped" in updateData.data) {
            const equippableUpdateData = updateData as Partial<ItemData<DS4EquippableItemDataType>>;
            const origin = `Actor.${this.id}.OwnedItem.${updateData._id}`;
            const effects = this.effects
                .filter((e) => e.data.origin === origin)
                .map((e) => {
                    const data = duplicate(e.data);
                    data.disabled = !equippableUpdateData.data.equipped;
                    return data;
                });
            if (effects.length > 0)
                this.updateEmbeddedEntity("ActiveEffect", (effects as unknown) as Record<string, unknown>);
        }
    }
}