import {
  MODULE_ID,
  SETTINGS,
  DEFAULT_REACTION,
  ACTION_TYPES,
  TRIGGER_TYPES,
  TRIGGER_PALETTE,
  ACTION_PALETTE
} from "../constants.js";
import { assignReactionToSelectedTokens, removeAssignment } from "./assignment-manager.js";

const { ApplicationV2, HandlebarsApplicationMixin } = foundry.applications.api;

export class ConfigurableReactionsConfigApp extends HandlebarsApplicationMixin(ApplicationV2) {
  static DEFAULT_OPTIONS = {
    id: "configurable-reactions-config",
    tag: "section",
    classes: ["configurable-reactions", "standard-form"],
    window: {
      title: "CONFIGURABLE_REACTIONS.App.Title",
      icon: "fa-solid fa-bolt"
    },
    position: {
      width: 1040,
      height: 820
    },
    actions: {
      createReaction: ConfigurableReactionsConfigApp.#onCreateReaction,
      saveReactionJson: ConfigurableReactionsConfigApp.#onSaveReactionJson,
      deleteReaction: ConfigurableReactionsConfigApp.#onDeleteReaction,
      assignSelectedTokens: ConfigurableReactionsConfigApp.#onAssignSelectedTokens,
      removeAssignment: ConfigurableReactionsConfigApp.#onRemoveAssignment,
      removeAction: ConfigurableReactionsConfigApp.#onRemoveAction,
      saveReactionBasics: ConfigurableReactionsConfigApp.#onSaveReactionBasics,
      clearTriggerSpell: ConfigurableReactionsConfigApp.#onClearTriggerSpell,
      clearActionSpell: ConfigurableReactionsConfigApp.#onClearActionSpell,
      removeActionStatus: ConfigurableReactionsConfigApp.#onRemoveActionStatus
    }
  };

  static PARTS = {
    main: {
      template: `modules/${MODULE_ID}/templates/reaction-config.hbs`
    }
  };

  async _prepareContext(options) {
    const reactions = foundry.utils.deepClone(game.settings.get(MODULE_ID, SETTINGS.REACTIONS) ?? []);
    const assignments = foundry.utils.deepClone(game.settings.get(MODULE_ID, SETTINGS.ASSIGNMENTS) ?? []);

    const selectedReactionId = this._selectedReactionId ?? reactions[0]?.id ?? null;
    const selectedReaction = reactions.find(r => r.id === selectedReactionId) ?? reactions[0] ?? null;
    this._selectedReactionId = selectedReaction?.id ?? null;

    const triggerPalette = TRIGGER_PALETTE.map(entry => ({
      ...entry,
      label: game.i18n.localize(entry.labelKey),
      hint: game.i18n.localize(entry.hintKey)
    }));

    const actionPalette = ACTION_PALETTE.map(entry => ({
      ...entry,
      label: game.i18n.localize(entry.labelKey),
      hint: game.i18n.localize(entry.hintKey)
    }));

    const activeTrigger = triggerPalette.find(t => t.type === selectedReaction?.trigger?.type) ?? null;
    const triggerSpellName = selectedReaction?.trigger?.spell?.itemName || selectedReaction?.trigger?.spell?.itemUuid || "";
    const activeTriggerAcceptsSpell = isSpellTrigger(selectedReaction?.trigger?.type);
    const statusEffects = getStatusEffectOptions();
    const visualActions = (selectedReaction?.actions ?? []).map((action, index) => {
      const paletteEntry = actionPalette.find(p => p.type === action.type);
      const selectedStatusIds = Array.from(new Set(action.statuses ?? []));
      const selectedStatuses = selectedStatusIds.map(statusId => resolveStatusEffect(statusId, statusEffects));

      return {
        ...action,
        index,
        label: paletteEntry?.label ?? action.type,
        icon: paletteEntry?.icon ?? "fa-solid fa-puzzle-piece",
        summary: summarizeAction(action, statusEffects),
        isSpellAction: action.type === ACTION_TYPES.CAST_SPELL_FROM_TOKEN,
        spellName: action.spellSelection?.itemName || action.spellSelection?.itemUuid || "",
        isStatusAction: action.type === ACTION_TYPES.APPLY_STATUS,
        selectedStatuses,
        availableStatuses: statusEffects.filter(status => !selectedStatusIds.includes(status.id))
      };
    });

    return {
      reactions,
      assignments: assignments.map(a => ({
        ...a,
        reactionName: reactions.find(r => r.id === a.reactionId)?.name ?? a.reactionId
      })),
      selectedReaction,
      selectedReactionJson: selectedReaction ? JSON.stringify(selectedReaction, null, 2) : "",
      triggerTypes: TRIGGER_TYPES,
      actionTypes: ACTION_TYPES,
      triggerPalette,
      actionPalette,
      activeTrigger,
      activeTriggerAcceptsSpell,
      triggerSpellName,
      visualActions,
      statusEffects
    };
  }

  _onRender(context, options) {
    super._onRender(context, options);

    this.element.querySelector("[name='selectedReactionId']")?.addEventListener("change", event => {
      this._selectedReactionId = event.currentTarget.value;
      this.render({ force: true });
    });

    this.#activateStatusSelectors();
    this.#activateDragAndDrop();
  }

  #activateStatusSelectors() {
    for (const select of this.element.querySelectorAll("[data-cr-status-select]")) {
      select.addEventListener("change", async event => {
        const actionIndex = Number(event.currentTarget.dataset.actionIndex);
        const statusId = event.currentTarget.value;
        if (!Number.isInteger(actionIndex) || !statusId) return;

        await this.#addActionStatus(actionIndex, statusId);
      });
    }
  }

  #activateDragAndDrop() {
    for (const draggable of this.element.querySelectorAll("[data-cr-drag]")) {
      draggable.setAttribute("draggable", "true");
      draggable.addEventListener("dragstart", event => {
        const payload = {
          kind: draggable.dataset.crDrag,
          type: draggable.dataset.crType,
          actionIndex: draggable.dataset.actionIndex ? Number(draggable.dataset.actionIndex) : null
        };
        event.dataTransfer.setData("application/json", JSON.stringify(payload));
        event.dataTransfer.setData("text/plain", JSON.stringify(payload));
        event.dataTransfer.effectAllowed = "copyMove";
      });
    }

    for (const dropZone of this.element.querySelectorAll("[data-cr-drop]")) {
      dropZone.addEventListener("dragover", event => {
        event.preventDefault();
        dropZone.classList.add("cr-drop-active");
        event.dataTransfer.dropEffect = "copy";
      });

      dropZone.addEventListener("dragleave", () => dropZone.classList.remove("cr-drop-active"));

      dropZone.addEventListener("drop", async event => {
        event.preventDefault();
        dropZone.classList.remove("cr-drop-active");

        event.stopPropagation();

        const payload = readDragPayload(event);
        if (!payload) return;

        const droppedItem = await resolveDroppedItem(payload);

        if (dropZone.dataset.crDrop === "trigger" && payload.kind === "trigger") {
          await this.#setTrigger(payload.type);
          return;
        }

        if (dropZone.dataset.crDrop === "trigger" && isSpellItem(droppedItem)) {
          await this.#setTriggerSpell(droppedItem);
          return;
        }

        if (dropZone.dataset.crDrop === "actions" && payload.kind === "action") {
          await this.#addAction(createDefaultAction(payload.type));
          return;
        }

        if (dropZone.dataset.crDrop === "actions" && isSpellItem(droppedItem)) {
          await this.#addAction(createDefaultAction(ACTION_TYPES.CAST_SPELL_FROM_TOKEN, droppedItem));
          return;
        }

        if (dropZone.dataset.crDrop === "action-spell" && isSpellItem(droppedItem)) {
          await this.#setActionSpell(Number(dropZone.dataset.actionIndex), droppedItem);
          return;
        }
      });
    }
  }

  static async #onCreateReaction(event, target) {
    const reactions = foundry.utils.deepClone(game.settings.get(MODULE_ID, SETTINGS.REACTIONS) ?? []);
    const reaction = foundry.utils.deepClone(DEFAULT_REACTION);
    reaction.id = foundry.utils.randomID();
    reaction.name = game.i18n.localize("CONFIGURABLE_REACTIONS.Reactions.NewReaction");

    reactions.push(reaction);
    await game.settings.set(MODULE_ID, SETTINGS.REACTIONS, reactions);

    this._selectedReactionId = reaction.id;
    this.render({ force: true });
  }

  static async #onSaveReactionJson(event, target) {
    const textarea = this.element.querySelector("[name='reactionJson']");
    if (!textarea) return;

    let reaction;
    try {
      reaction = JSON.parse(textarea.value);
    } catch (error) {
      ui.notifications.error(game.i18n.localize("CONFIGURABLE_REACTIONS.Errors.InvalidJson"));
      return;
    }

    if (!reaction.id) reaction.id = foundry.utils.randomID();
    if (!reaction.name) reaction.name = game.i18n.localize("CONFIGURABLE_REACTIONS.Reactions.NewReaction");
    reaction.actions ??= [];

    const reactions = foundry.utils.deepClone(game.settings.get(MODULE_ID, SETTINGS.REACTIONS) ?? []);
    const index = reactions.findIndex(r => r.id === reaction.id);
    if (index >= 0) reactions[index] = reaction;
    else reactions.push(reaction);

    await game.settings.set(MODULE_ID, SETTINGS.REACTIONS, reactions);
    this._selectedReactionId = reaction.id;
    this.render({ force: true });
  }

  static async #onDeleteReaction(event, target) {
    const reactionId = this.element.querySelector("[name='selectedReactionId']")?.value;
    if (!reactionId) return;

    const confirmed = await foundry.applications.api.DialogV2.confirm({
      window: { title: game.i18n.localize("CONFIGURABLE_REACTIONS.Reactions.Delete") },
      content: `<p>${game.i18n.localize("CONFIGURABLE_REACTIONS.Reactions.DeleteConfirm")}</p>`
    });

    if (!confirmed) return;

    const reactions = foundry.utils.deepClone(game.settings.get(MODULE_ID, SETTINGS.REACTIONS) ?? [])
      .filter(r => r.id !== reactionId);
    const assignments = foundry.utils.deepClone(game.settings.get(MODULE_ID, SETTINGS.ASSIGNMENTS) ?? [])
      .filter(a => a.reactionId !== reactionId);

    await game.settings.set(MODULE_ID, SETTINGS.REACTIONS, reactions);
    await game.settings.set(MODULE_ID, SETTINGS.ASSIGNMENTS, assignments);

    this._selectedReactionId = reactions[0]?.id ?? null;
    this.render({ force: true });
  }

  static async #onAssignSelectedTokens(event, target) {
    const reactionId = this.element.querySelector("[name='selectedReactionId']")?.value;
    await assignReactionToSelectedTokens(reactionId);
    this.render({ force: true });
  }

  static async #onRemoveAssignment(event, target) {
    const assignmentId = target.dataset.assignmentId;
    await removeAssignment(assignmentId);
    this.render({ force: true });
  }

  static async #onRemoveAction(event, target) {
    const actionIndex = Number(target.dataset.actionIndex);
    if (!Number.isInteger(actionIndex)) return;

    await this.#mutateSelectedReaction(reaction => {
      reaction.actions ??= [];
      reaction.actions.splice(actionIndex, 1);
    });
  }

  static async #onClearTriggerSpell(event, target) {
    await this.#mutateSelectedReaction(reaction => {
      reaction.trigger ??= {};
      delete reaction.trigger.spell;
    });
  }

  static async #onClearActionSpell(event, target) {
    const actionIndex = Number(target.dataset.actionIndex);
    if (!Number.isInteger(actionIndex)) return;

    await this.#mutateSelectedReaction(reaction => {
      const action = reaction.actions?.[actionIndex];
      if (!action || action.type !== ACTION_TYPES.CAST_SPELL_FROM_TOKEN) return;
      action.spellSelection = { mode: "itemName", itemName: "" };
    });
  }

  static async #onRemoveActionStatus(event, target) {
    const actionIndex = Number(target.dataset.actionIndex);
    const statusId = target.dataset.statusId;
    if (!Number.isInteger(actionIndex) || !statusId) return;

    await this.#mutateSelectedReaction(reaction => {
      const action = reaction.actions?.[actionIndex];
      if (!action || action.type !== ACTION_TYPES.APPLY_STATUS) return;
      action.statuses = (action.statuses ?? []).filter(id => id !== statusId);
    });
  }

  static async #onSaveReactionBasics(event, target) {
    const name = this.element.querySelector("[name='reactionName']")?.value?.trim();
    const enabled = this.element.querySelector("[name='reactionEnabled']")?.checked === true;

    await this.#mutateSelectedReaction(reaction => {
      if (name) reaction.name = name;
      reaction.enabled = enabled;
    });
  }

  async #setTrigger(triggerType) {
    await this.#mutateSelectedReaction(reaction => {
      reaction.trigger ??= {};
      reaction.trigger.type = triggerType;
      if (!isSpellTrigger(triggerType)) delete reaction.trigger.spell;
    });
  }

  async #setTriggerSpell(item) {
    await this.#mutateSelectedReaction(reaction => {
      reaction.trigger ??= {};
      if (!isSpellTrigger(reaction.trigger.type)) reaction.trigger.type = TRIGGER_TYPES.SPELL_SEEN;
      reaction.trigger.spell = buildSpellSelection(item);
    });
  }

  async #setActionSpell(actionIndex, item) {
    if (!Number.isInteger(actionIndex)) return;

    await this.#mutateSelectedReaction(reaction => {
      const action = reaction.actions?.[actionIndex];
      if (!action || action.type !== ACTION_TYPES.CAST_SPELL_FROM_TOKEN) return;
      action.spellSelection = buildSpellSelection(item);
    });
  }

  async #addAction(action) {
    await this.#mutateSelectedReaction(reaction => {
      reaction.actions ??= [];
      reaction.actions.push(action);
    });
  }

  async #addActionStatus(actionIndex, statusId) {
    await this.#mutateSelectedReaction(reaction => {
      const action = reaction.actions?.[actionIndex];
      if (!action || action.type !== ACTION_TYPES.APPLY_STATUS) return;

      action.statuses ??= [];
      if (!action.statuses.includes(statusId)) action.statuses.push(statusId);
    });
  }

  async #mutateSelectedReaction(mutator) {
    const reactions = foundry.utils.deepClone(game.settings.get(MODULE_ID, SETTINGS.REACTIONS) ?? []);
    const reaction = reactions.find(r => r.id === this._selectedReactionId);
    if (!reaction) return;

    mutator(reaction);
    await game.settings.set(MODULE_ID, SETTINGS.REACTIONS, reactions);
    this.render({ force: true });
  }
}

function readDragPayload(event) {
  const raw = event.dataTransfer.getData("application/json") || event.dataTransfer.getData("text/plain");
  if (!raw) return null;

  try {
    return JSON.parse(raw);
  } catch (error) {
    console.warn(`${MODULE_ID} | Invalid drag payload`, error);
    return null;
  }
}

async function resolveDroppedItem(data) {
  if (!data) return null;

  if (data.uuid) {
    const document = await fromUuid(data.uuid);
    if (document?.documentName === "Item") return document;
  }

  if (data.type === "Item" && data.id) {
    return game.items.get(data.id) ?? null;
  }

  return null;
}

function isSpellItem(item) {
  return item?.documentName === "Item" && item.type === "spell";
}

function isSpellTrigger(type) {
  return [TRIGGER_TYPES.SPELL_SEEN, TRIGGER_TYPES.SPELL_CAST_START, TRIGGER_TYPES.SPELL_CAST_COMPLETE].includes(type);
}

function buildSpellSelection(item) {
  return {
    mode: "itemName",
    itemName: item.name
  };
}

function createDefaultAction(type, item = null) {
  switch (type) {
    case ACTION_TYPES.TELEPORT:
      return {
        id: foundry.utils.randomID(),
        type: ACTION_TYPES.TELEPORT,
        enabled: true,
        radius: 30,
        askOwner: false,
        snapToGrid: true,
        maxAttempts: 80,
        consumeOnFailure: false
      };

    case ACTION_TYPES.APPLY_STATUS:
      return {
        id: foundry.utils.randomID(),
        type: ACTION_TYPES.APPLY_STATUS,
        enabled: true,
        statuses: [],
        duration: {
          type: "rounds",
          value: 1
        }
      };

    case ACTION_TYPES.CAST_SPELL_FROM_TOKEN:
      return {
        id: foundry.utils.randomID(),
        type: ACTION_TYPES.CAST_SPELL_FROM_TOKEN,
        enabled: true,
        casterMode: "affectedToken",
        spellSelection: item ? buildSpellSelection(item) : {
          mode: "itemName",
          itemName: ""
        },
        targetMode: "self",
        consumeSlot: true,
        consumeUses: true
      };

    case ACTION_TYPES.USE_INVENTORY_ITEM:
      return {
        id: foundry.utils.randomID(),
        type: ACTION_TYPES.USE_INVENTORY_ITEM,
        enabled: true,
        itemSelection: {
          mode: "itemName",
          itemName: ""
        },
        userMode: "affectedToken",
        targetMode: "self",
        activationMode: "openSheet",
        consumeUses: true
      };

    default:
      return {
        id: foundry.utils.randomID(),
        type,
        enabled: true
      };
  }
}

function getStatusEffectOptions() {
  return (CONFIG.statusEffects ?? []).map(status => ({
    id: status.id,
    label: game.i18n.localize(status.name ?? status.label ?? status.id),
    icon: status.img ?? status.icon ?? "icons/svg/aura.svg"
  })).sort((a, b) => a.label.localeCompare(b.label, game.i18n.lang));
}

function resolveStatusEffect(statusId, statusEffects = getStatusEffectOptions()) {
  return statusEffects.find(status => status.id === statusId) ?? {
    id: statusId,
    label: statusId,
    icon: "icons/svg/aura.svg"
  };
}

function summarizeAction(action, statusEffects = getStatusEffectOptions()) {
  switch (action.type) {
    case ACTION_TYPES.TELEPORT:
      return game.i18n.format("CONFIGURABLE_REACTIONS.Actions.Teleport.Summary", {
        radius: Number(action.radius) || 30,
        mode: action.askOwner ? game.i18n.localize("CONFIGURABLE_REACTIONS.Actions.Teleport.OwnerMode") : game.i18n.localize("CONFIGURABLE_REACTIONS.Actions.Teleport.RandomMode")
      });

    case ACTION_TYPES.APPLY_STATUS: {
      const statuses = action.statuses?.length
        ? action.statuses.map(statusId => resolveStatusEffect(statusId, statusEffects).label).join(", ")
        : game.i18n.localize("CONFIGURABLE_REACTIONS.Actions.ApplyStatus.NoStatuses");
      const duration = action.duration?.type === "unlimited" ? game.i18n.localize("CONFIGURABLE_REACTIONS.Duration.Unlimited") : `${action.duration?.value ?? 1} ${action.duration?.type ?? "rounds"}`;
      return `${statuses} · ${duration}`;
    }

    case ACTION_TYPES.CAST_SPELL_FROM_TOKEN:
      return action.spellSelection?.itemName || action.spellSelection?.itemUuid || game.i18n.localize("CONFIGURABLE_REACTIONS.Actions.CastSpellFromToken.Unconfigured");

    case ACTION_TYPES.USE_INVENTORY_ITEM:
      return action.itemSelection?.itemName || action.itemSelection?.itemUuid || game.i18n.localize("CONFIGURABLE_REACTIONS.Actions.UseInventoryItem.Unconfigured");

    default:
      return action.type;
  }
}