import {d20Roll, damageRoll} from "../dice.js";
import AbilityUseDialog from "../apps/ability-use-dialog.js";
import AbilityTemplate from "../pixi/ability-template.js";

/**
 * Override and extend the basic :class:`Item` implementation
 */
export default class Item5e extends Item {

  /* -------------------------------------------- */
  /*  Item Properties                             */
  /* -------------------------------------------- */

  /**
   * Determine which ability score modifier is used by this item
   * @type {string|null}
   */
  get abilityMod() {
    const itemData = this.data.data;
    if (!("ability" in itemData)) return null;

    // Case 1 - defined directly by the item
    if (itemData.ability) return itemData.ability;

    // Case 2 - inferred from a parent actor
    else if (this.actor) {
      const actorData = this.actor.data.data;

      // Powers - Use Actor powercasting modifier
      if (this.data.type === "power") return actorData.attributes.powercasting || "int";

      // Tools - default to Intelligence
      else if (this.data.type === "tool") return "int";

      // Weapons
      else if (this.data.type === "weapon") {
        const wt = itemData.weaponType;

        // Melee weapons - Str or Dex if Finesse (PHB pg. 147)
        if ( ["simpleVW", "martialVW", "simpleLW", "martialLW"].includes(wt) ) {
          if (itemData.properties.fin === true) {   // Finesse weapons
            return (actorData.abilities["dex"].mod >= actorData.abilities["str"].mod) ? "dex" : "str";
          }
          return "str";
        }

        // Ranged weapons - Dex (PH p.194)
        else if ( ["simpleB", "martialB"].includes(wt) ) return "dex";
      }
      return "str";
    }

    // Case 3 - unknown
    return null
  }

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

  /**
   * Does the Item implement an attack roll as part of its usage
   * @type {boolean}
   */
  get hasAttack() {
    return ["mwak", "rwak", "mpak", "rpak"].includes(this.data.data.actionType);
  }

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

  /**
   * Does the Item implement a damage roll as part of its usage
   * @type {boolean}
   */
  get hasDamage() {
    return !!(this.data.data.damage && this.data.data.damage.parts.length);
  }

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

  /**
   * Does the Item implement a versatile damage roll as part of its usage
   * @type {boolean}
   */
  get isVersatile() {
    return !!(this.hasDamage && this.data.data.damage.versatile);
  }

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

  /**
   * Does the item provide an amount of healing instead of conventional damage?
   * @return {boolean}
   */
  get isHealing() {
    return (this.data.data.actionType === "heal") && this.data.data.damage.parts.length;
  }

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

  /**
   * Does the Item implement a saving throw as part of its usage
   * @type {boolean}
   */
  get hasSave() {
    return !!(this.data.data.save && this.data.data.save.ability);
  }

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

  /**
   * Does the Item have a target
   * @type {boolean}
   */
  get hasTarget() {
    const target = this.data.data.target;
    return target && !["none",""].includes(target.type);
  }

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

  /**
   * Does the Item have an area of effect target
   * @type {boolean}
   */
  get hasAreaTarget() {
    const target = this.data.data.target;
    return target && (target.type in CONFIG.SW5E.areaTargetTypes);
  }

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

  /**
   * A flag for whether this Item is limited in it's ability to be used by charges or by recharge.
   * @type {boolean}
   */
  get hasLimitedUses() {
    let chg = this.data.data.recharge || {};
    let uses = this.data.data.uses || {};
    return !!chg.value || (!!uses.per && (uses.max > 0));
  }

  /* -------------------------------------------- */
  /*	Data Preparation														*/
  /* -------------------------------------------- */

  /**
   * Augment the basic Item data model with additional dynamic data.
   */
  prepareData() {
    super.prepareData();

    // Get the Item's data
    const itemData = this.data;
    const data = itemData.data;
    const C = CONFIG.SW5E;
    const labels = {};

    // Classes
    if ( itemData.type === "class" ) {
      data.levels = Math.clamped(data.levels, 1, 20);
    }

    // Power Level,  School, and Components
    if ( itemData.type === "power" ) {
      labels.level = C.powerLevels[data.level];
      labels.school = C.powerSchools[data.school];
      labels.components = Object.entries(data.components).reduce((arr, c) => {
        if ( c[1] !== true ) return arr;
        arr.push(c[0].titleCase().slice(0, 1));
        return arr;
      }, []);
      labels.materials = data?.materials?.value ?? null;
    }

    // Feat Items
    else if ( itemData.type === "feat" ) {
      const act = data.activation;
      if ( act && (act.type === C.abilityActivationTypes.legendary) ) labels.featType = game.i18n.localize("SW5E.LegendaryActionLabel");
      else if ( act && (act.type === C.abilityActivationTypes.lair) ) labels.featType = game.i18n.localize("SW5E.LairActionLabel");
      else if ( act && act.type ) labels.featType = game.i18n.localize(data.damage.length ? "SW5E.Attack" : "SW5E.Action");
      else labels.featType = game.i18n.localize("SW5E.Passive");
    }

	// Species Items
	else if ( itemData.type === "species" ) {
	//  labels.species = C.species[data.species];
	}
	// Archetype Items
	else if ( itemData.type === "archetype" ) {
    //  labels.archetype = C.archetype[data.archetype];
    }
	// Background Items
	else if ( itemData.type === "background" ) {
		
	}
	// Class Feature Items
    else if ( itemData.type === "classfeature" ) {
	
	}
	// Lightsaber Form Items
	else if ( itemData.type === "lightsaberform" ) {
	
	}

    // Equipment Items
    else if ( itemData.type === "equipment" ) {
      labels.armor = data.armor.value ? `${data.armor.value} ${game.i18n.localize("SW5E.AC")}` : "";
    }

    // Activated Items
    if ( data.hasOwnProperty("activation") ) {

      // Ability Activation Label
      let act = data.activation || {};
      if ( act ) labels.activation = [act.cost, C.abilityActivationTypes[act.type]].filterJoin(" ");

      // Target Label
      let tgt = data.target || {};
      if (["none", "touch", "self"].includes(tgt.units)) tgt.value = null;
      if (["none", "self"].includes(tgt.type)) {
        tgt.value = null;
        tgt.units = null;
      }
      labels.target = [tgt.value, C.distanceUnits[tgt.units], C.targetTypes[tgt.type]].filterJoin(" ");

      // Range Label
      let rng = data.range || {};
      if (["none", "touch", "self"].includes(rng.units) || (rng.value === 0)) {
        rng.value = null;
        rng.long = null;
      }
      labels.range = [rng.value, rng.long ? `/ ${rng.long}` : null, C.distanceUnits[rng.units]].filterJoin(" ");

      // Duration Label
      let dur = data.duration || {};
      if (["inst", "perm"].includes(dur.units)) dur.value = null;
      labels.duration = [dur.value, C.timePeriods[dur.units]].filterJoin(" ");

      // Recharge Label
      let chg = data.recharge || {};
      labels.recharge = `${game.i18n.localize("SW5E.Recharge")} [${chg.value}${parseInt(chg.value) < 6 ? "+" : ""}]`;
    }

    // Item Actions
    if ( data.hasOwnProperty("actionType") ) {

      // Saving throws for unowned items
      const save = data.save;
      if ( save?.ability && !this.isOwned ) {
        if ( save.scaling !== "flat" ) save.dc = null;
        labels.save = game.i18n.format("SW5E.SaveDC", {dc: save.dc || "", ability: C.abilities[save.ability]});
      }

      // Damage
      let dam = data.damage || {};
      if ( dam.parts ) {
        labels.damage = dam.parts.map(d => d[0]).join(" + ").replace(/\+ -/g, "- ");
        labels.damageTypes = dam.parts.map(d => C.damageTypes[d[1]]).join(", ");
      }
    }

    // Assign labels
    this.labels = labels;
  }

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

  /**
   * Roll the item to Chat, creating a chat card which contains follow up attack or damage roll options
   * @param {boolean} [configureDialog]     Display a configuration dialog for the item roll, if applicable?
   * @param {string} [rollMode]             The roll display mode with which to display (or not) the card
   * @param {boolean} [createMessage]       Whether to automatically create a chat message (if true) or simply return
   *                                        the prepared chat message data (if false).
   * @return {Promise}
   */
  async roll({configureDialog=true, rollMode=null, createMessage=true}={}) {

    // Basic template rendering data
    const token = this.actor.token;
    const templateData = {
      actor: this.actor,
      tokenId: token ? `${token.scene._id}.${token.id}` : null,
      item: this.data,
      data: this.getChatData(),
      labels: this.labels,
      hasAttack: this.hasAttack,
      isHealing: this.isHealing,
      hasDamage: this.hasDamage,
      isVersatile: this.isVersatile,
      isPower: this.data.type === "power",
      hasSave: this.hasSave,
      hasAreaTarget: this.hasAreaTarget
    };

    // For feature items, optionally show an ability usage dialog
    if (this.data.type === "feat") {
      let configured = await this._rollFeat(configureDialog);
      if ( configured === false ) return;
    } else if ( this.data.type === "consumable" ) {
      let configured = await this._rollConsumable(configureDialog);
      if ( configured === false ) return;
    }

    // For items which consume a resource, handle that here
    const allowed = await this._handleResourceConsumption({isCard: true, isAttack: false});
    if ( allowed === false ) return;

    // Render the chat card template
    const templateType = ["tool"].includes(this.data.type) ? this.data.type : "item";
    const template = `systems/sw5e/templates/chat/${templateType}-card.html`;
    const html = await renderTemplate(template, templateData);

    // Basic chat message data
    const chatData = {
      user: game.user._id,
      type: CONST.CHAT_MESSAGE_TYPES.OTHER,
      content: html,
      flavor: this.name,
      speaker: {
        actor: this.actor._id,
        token: this.actor.token,
        alias: this.actor.name
      },
      flags: {"core.canPopout": true}
    };

    // If the consumable was destroyed in the process - embed the item data in the surviving message
    if ( (this.data.type === "consumable") && !this.actor.items.has(this.id) ) {
      chatData.flags["sw5e.itemData"] = this.data;
    }

    // Toggle default roll mode
    rollMode = rollMode || game.settings.get("core", "rollMode");
    if ( ["gmroll", "blindroll"].includes(rollMode) ) chatData["whisper"] = ChatMessage.getWhisperRecipients("GM");
    if ( rollMode === "blindroll" ) chatData["blind"] = true;

    // Create the chat message
    if ( createMessage ) return ChatMessage.create(chatData);
    else return chatData;
  }

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

    /**
   * For items which consume a resource, handle the consumption of that resource when the item is used.
   * There are four types of ability consumptions which are handled:
   * 1. Ammunition (on attack rolls)
   * 2. Attributes (on card usage)
   * 3. Materials (on card usage)
   * 4. Item Charges (on card usage)
   *
   * @param {boolean} isCard      Is the item card being played?
   * @param {boolean} isAttack    Is an attack roll being made?
   * @return {Promise<boolean>}   Can the item card or attack roll be allowed to proceed?
   * @private
   */
  async _handleResourceConsumption({isCard=false, isAttack=false}={}) {
    const itemData = this.data.data;
    const consume = itemData.consume || {};
    if ( !consume.type ) return true;
    const actor = this.actor;
    const typeLabel = CONFIG.SW5E.abilityConsumptionTypes[consume.type];
    const amount = parseInt(consume.amount || 1);

    // Only handle certain types for certain actions
    if ( ((consume.type === "ammo") && !isAttack ) || ((consume.type !== "ammo") && !isCard) ) return true;

    // No consumed target set
    if ( !consume.target ) {
      ui.notifications.warn(game.i18n.format("SW5E.ConsumeWarningNoResource", {name: this.name, type: typeLabel}));
      return false;
    }

    // Identify the consumed resource and it's quantity
    let consumed = null;
    let quantity = 0;
    switch ( consume.type ) {
      case "attribute":
        consumed = getProperty(actor.data.data, consume.target);
        quantity = consumed || 0;
        break;
      case "ammo":
      case "material":
        consumed = actor.items.get(consume.target);
        quantity = consumed ? consumed.data.data.quantity : 0;
        break;
      case "charges":
        consumed = actor.items.get(consume.target);
        quantity = consumed ? consumed.data.data.uses.value : 0;
        break;
    }

    // Verify that the consumed resource is available
    if ( [null, undefined].includes(consumed) ) {
      ui.notifications.warn(game.i18n.format("SW5E.ConsumeWarningNoSource", {name: this.name, type: typeLabel}));
      return false;
    }
    let remaining = quantity - amount;
    if ( remaining < 0) {
      ui.notifications.warn(game.i18n.format("SW5E.ConsumeWarningNoQuantity", {name: this.name, type: typeLabel}));
      return false;
    }

    // Update the consumed resource
    switch ( consume.type ) {
      case "attribute":
        await this.actor.update({[`data.${consume.target}`]: remaining});
        break;
      case "ammo":
      case "material":
        await consumed.update({"data.quantity": remaining});
        break;
      case "charges":
        await consumed.update({"data.uses.value": remaining});
    }
    return true;
  }

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

  /**
   * Additional rolling steps when rolling a feat-type item
   * @private
   * @return {boolean} whether the roll should be prevented
   */
  async _rollFeat(configureDialog) {
    if ( this.data.type !== "feat" ) throw new Error("Wrong Item type");

    // Configure whether to consume a limited use or to place a template
    const charge = this.data.data.recharge;
    const uses = this.data.data.uses;
    let usesCharges = !!uses.per && (uses.max > 0);
    let placeTemplate = false;
    let consume = charge.value || usesCharges;

    // Determine whether the feat uses charges
    configureDialog = configureDialog && (consume || this.hasAreaTarget);
    if ( configureDialog ) {
      const usage = await AbilityUseDialog.create(this);
      if ( usage === null ) return false;
      consume = Boolean(usage.get("consumeUse"));
      placeTemplate = Boolean(usage.get("placeTemplate"));
    }

    // Update Item data
    const current = getProperty(this.data, "data.uses.value") || 0;
    if ( consume && charge.value ) {
      if ( !charge.charged ) {
        ui.notifications.warn(game.i18n.format("SW5E.ItemNoUses", {name: this.name}));
        return false;
      }
      else await this.update({"data.recharge.charged": false});
    }
    else if ( consume && usesCharges ) {
      if ( uses.value <= 0 ) {
        ui.notifications.warn(game.i18n.format("SW5E.ItemNoUses", {name: this.name}));
        return false;
      }
      await this.update({"data.uses.value": Math.max(current - 1, 0)});
    }

    // Maybe initiate template placement workflow
    if ( this.hasAreaTarget && placeTemplate ) {
      const template = AbilityTemplate.fromItem(this);
      if ( template ) template.drawPreview();
      if ( this.owner && this.owner.sheet ) this.owner.sheet.minimize();
    }
    return true;
  }

  /* -------------------------------------------- */
  /*  Chat Cards																	*/
  /* -------------------------------------------- */

  /**
   * Prepare an object of chat data used to display a card for the Item in the chat log
   * @param {Object} htmlOptions    Options used by the TextEditor.enrichHTML function
   * @return {Object}               An object of chat data to render
   */
  getChatData(htmlOptions={}) {
    const data = duplicate(this.data.data);
    const labels = this.labels;

    // Rich text description
    data.description.value = TextEditor.enrichHTML(data.description.value, htmlOptions);

    // Item type specific properties
    const props = [];
    const fn = this[`_${this.data.type}ChatData`];
    if ( fn ) fn.bind(this)(data, labels, props);

    // General equipment properties
    if ( data.hasOwnProperty("equipped") && !["loot", "tool"].includes(this.data.type) ) {
      props.push(
        game.i18n.localize(data.equipped ? "SW5E.Equipped" : "SW5E.Unequipped"),
        game.i18n.localize(data.proficient ? "SW5E.Proficient" : "SW5E.NotProficient"),
      );
    }

    // Ability activation properties
    if ( data.hasOwnProperty("activation") ) {
      props.push(
        labels.activation + (data.activation?.condition ? ` (${data.activation.condition})` : ""),
        labels.target,
        labels.range,
        labels.duration
      );
    }

    // Filter properties and return
    data.properties = props.filter(p => !!p);
    return data;
  }

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

  /**
   * Prepare chat card data for equipment type items
   * @private
   */
  _equipmentChatData(data, labels, props) {
    props.push(
      CONFIG.SW5E.equipmentTypes[data.armor.type],
      labels.armor || null,
      data.stealth.value ? game.i18n.localize("SW5E.StealthDisadvantage") : null
    );
  }

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

  /**
   * Prepare chat card data for weapon type items
   * @private
   */
  _weaponChatData(data, labels, props) {
    props.push(
      CONFIG.SW5E.weaponTypes[data.weaponType],
    );
  }

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

  /**
   * Prepare chat card data for consumable type items
   * @private
   */
  _consumableChatData(data, labels, props) {
    props.push(
      CONFIG.SW5E.consumableTypes[data.consumableType],
      data.uses.value + "/" + data.uses.max + " " + game.i18n.localize("SW5E.Charges")
    );
    data.hasCharges = data.uses.value >= 0;
  }

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

  /**
   * Prepare chat card data for tool type items
   * @private
   */
  _toolChatData(data, labels, props) {
    props.push(
      CONFIG.SW5E.abilities[data.ability] || null,
      CONFIG.SW5E.proficiencyLevels[data.proficient || 0]
    );
  }

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

  /**
   * Prepare chat card data for tool type items
   * @private
   */
  _lootChatData(data, labels, props) {
    props.push(
      game.i18n.localize("SW5E.ItemTypeLoot"),
      data.weight ? data.weight + " " + game.i18n.localize("SW5E.AbbreviationLbs") : null
    );
  }

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

  /**
   * Render a chat card for Power type data
   * @return {Object}
   * @private
   */
  _powerChatData(data, labels, props) {
    props.push(
      labels.level,
      labels.components + (labels.materials ? ` (${labels.materials})` : "")
    );
  }

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

  /**
   * Prepare chat card data for items of the "Feat" type
   * @private
   */
  _featChatData(data, labels, props) {
    props.push(data.requirements);
  }

  /* -------------------------------------------- */
  /*  Item Rolls - Attack, Damage, Saves, Checks  */
  /* -------------------------------------------- */

  /**
   * Place an attack roll using an item (weapon, feat, power, or equipment)
   * Rely upon the d20Roll logic for the core implementation
   *
   * @param {object} options        Roll options which are configured and provided to the d20Roll function
   * @return {Promise<Roll|null>}   A Promise which resolves to the created Roll instance
   */
  async rollAttack(options={}) {
    const itemData = this.data.data;
    const actorData = this.actor.data.data;
    const flags = this.actor.data.flags.sw5e || {};
    if ( !this.hasAttack ) {
      throw new Error("You may not place an Attack Roll with this Item.");
    }
    let title = `${this.name} - ${game.i18n.localize("SW5E.AttackRoll")}`;
    const rollData = this.getRollData();

    // Define Roll bonuses
    const parts = [`@mod`];
    if ( (this.data.type !== "weapon") || itemData.proficient ) {
      parts.push("@prof");
    }

    // Attack Bonus
    const actorBonus = actorData?.bonuses?.[itemData.actionType] || {};
    if ( itemData.attackBonus || actorBonus.attack ) {
      parts.push("@atk");
      rollData["atk"] = [itemData.attackBonus, actorBonus.attack].filterJoin(" + ");
    }

      // Ammunition Bonus
      delete this._ammo;
      const consume = itemData.consume;
      if ( consume?.type === "ammo" ) {
        const ammo = this.actor.items.get(consume.target);
        if(ammo?.data){
          const q = ammo.data.data.quantity;
          const consumeAmount = consume.amount ?? 0;
          if ( q && (q - consumeAmount >= 0) ) {
            let ammoBonus = ammo.data.data.attackBonus;
            if ( ammoBonus ) {
              parts.push("@ammo");
              rollData["ammo"] = ammoBonus;
              title += ` [${ammo.name}]`;
              this._ammo = ammo;
            }
          }
        //}else{
        //  ui.notifications.error(game.i18n.format("SW5E.ConsumeWarningNoResource", {name: this.name, type: typeLabel}));
        }
      }
    
    // Compose roll options
    const rollConfig = mergeObject({
      parts: parts,
      actor: this.actor,
      data: rollData,
      title: title,
      speaker: ChatMessage.getSpeaker({actor: this.actor}),
      dialogOptions: {
        width: 400,
        top: options.event ? options.event.clientY - 80 : null,
        left: window.innerWidth - 710
      },
      messageData: {"flags.sw5e.roll": {type: "attack", itemId: this.id }}
    }, options);
    rollConfig.event = options.event;

    // Expanded weapon critical threshold
    if (( this.data.type === "weapon" ) && flags.weaponCriticalThreshold) {
      rollConfig.critical = parseInt(flags.weaponCriticalThreshold);
    }

    // Elven Accuracy
    if ( ["weapon", "power"].includes(this.data.type) ) {
      if (flags.elvenAccuracy && ["dex", "int", "wis", "cha"].includes(this.abilityMod)) {
        rollConfig.elvenAccuracy = true;
      }
    }

    // Apply Halfling Lucky
    if ( flags.halflingLucky ) rollConfig.halflingLucky = true;

    // Invoke the d20 roll helper
    const roll = await d20Roll(rollConfig);
    if ( roll === false ) return null;

    // Handle resource consumption if the attack roll was made
    const allowed = await this._handleResourceConsumption({isCard: false, isAttack: true});
    if ( allowed === false ) return null;
    return roll;
  }

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

  /**
   * Place a damage roll using an item (weapon, feat, power, or equipment)
   * Rely upon the damageRoll logic for the core implementation
   *
   * @return {Promise<Roll>}   A Promise which resolves to the created Roll instance
   */
  rollDamage({event, powerLevel=null, versatile=false}={}) {
    const itemData = this.data.data;
    const actorData = this.actor.data.data;
    if ( !this.hasDamage ) {
      throw new Error("You may not make a Damage Roll with this Item.");
    }
    const messageData = {"flags.sw5e.roll": {type: "damage", itemId: this.id }};

    // Get roll data
    const rollData = this.getRollData();
    if ( powerLevel ) rollData.item.level = powerLevel;

    // Get message labels
    const title = `${this.name} - ${game.i18n.localize("SW5E.DamageRoll")}`;
    let flavor = this.labels.damageTypes.length ? `${title} (${this.labels.damageTypes})` : title;

    // Define Roll parts
    const parts = itemData.damage.parts.map(d => d[0]);

    // Adjust damage from versatile usage
    if ( versatile && itemData.damage.versatile ) {
      parts[0] = itemData.damage.versatile;
      messageData["flags.sw5e.roll"].versatile = true;
    }

    // Scale damage from up-casting powers
    if ( (this.data.type === "power") ) {
      if ( (itemData.scaling.mode === "atwill") ) {
        const level = this.actor.data.type === "character" ? actorData.details.level : actorData.details.powerLevel;
        this._scaleAtWillDamage(parts, itemData.scaling.formula, level, rollData);
      }
      else if ( powerLevel && (itemData.scaling.mode === "level") && itemData.scaling.formula ) {
        const scaling = itemData.scaling.formula;
        this._scalePowerDamage(parts, itemData.level, powerLevel, scaling, rollData);
      }
    }

    // Define Roll Data
    const actorBonus = getProperty(actorData, `bonuses.${itemData.actionType}`) || {};
    if ( actorBonus.damage && parseInt(actorBonus.damage) !== 0 ) {
      parts.push("@dmg");
      rollData["dmg"] = actorBonus.damage;
    }

    // Ammunition Damage
    if ( this._ammo ) {
      parts.push("@ammo");
      rollData["ammo"] = this._ammo.data.data.damage.parts.map(p => p[0]).join("+");
      flavor += ` [${this._ammo.name}]`;
      delete this._ammo;
    }

    // Call the roll helper utility
    return damageRoll({
      event: event,
      parts: parts,
      actor: this.actor,
      data: rollData,
      title: title,
      flavor: flavor,
      speaker: ChatMessage.getSpeaker({actor: this.actor}),
      dialogOptions: {
        width: 400,
        top: event ? event.clientY - 80 : null,
        left: window.innerWidth - 710
      },
      messageData
    });
  }

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

  /**
   * Adjust an at-will damage formula to scale it for higher level characters and monsters
   * @private
   */
  _scaleAtWillDamage(parts, scale, level, rollData) {
    const add = Math.floor((level + 1) / 6);
    if ( add === 0 ) return;

    // FUTURE SOLUTION - 0.7.0 AND LATER
    if (isNewerVersion(game.data.version, "0.6.9")) {
      this._scaleDamage(parts, scale || parts.join(" + "), add, rollData)

    }

    // LEGACY SOLUTION - 0.6.x AND OLDER
    // TODO: Deprecate the legacy solution one FVTT 0.7.x is RELEASE
    else {
      if ( scale && (scale !== parts[0]) ) {
        parts[0] = parts[0] + " + " + scale.replace(new RegExp(Roll.diceRgx, "g"), (match, nd, d) => `${add}d${d}`);
      } else {
        parts[0] = parts[0].replace(new RegExp(Roll.diceRgx, "g"), (match, nd, d) => `${parseInt(nd)+add}d${d}`);
      }
    }
  }

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

  /**
   * Adjust the power damage formula to scale it for power level up-casting
   * @param {Array} parts         The original damage parts
   * @param {number} baseLevel    The default power level
   * @param {number} powerLevel   The casted power level
   * @param {string} formula      The scaling formula
   * @param {object} rollData     A data object that should be applied to the scaled damage roll
   * @return {string[]}           The scaled roll parts
   * @private
   */
  _scalePowerDamage(parts, baseLevel, powerLevel, formula, rollData) {
    const upcastLevels = Math.max(powerLevel - baseLevel, 0);
    if ( upcastLevels === 0 ) return parts;

    // FUTURE SOLUTION - 0.7.0 AND LATER
    if (isNewerVersion(game.data.version, "0.6.9")) {
      this._scaleDamage(parts, formula, upcastLevels, rollData);
    }

    // LEGACY SOLUTION - 0.6.x AND OLDER
    // TODO: Deprecate the legacy solution one FVTT 0.7.x is RELEASE
    else {
      const bonus = new Roll(formula);
      bonus.alter(0, upcastLevels);
      parts.push(bonus.formula);
    }
    return parts;
  }

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

  /**
   * Scale an array of damage parts according to a provided scaling formula and scaling multiplier
   * @param {string[]} parts    Initial roll parts
   * @param {string} scaling    A scaling formula
   * @param {number} times      A number of times to apply the scaling formula
   * @param {object} rollData   A data object that should be applied to the scaled damage roll
   * @return {string[]}         The scaled roll parts
   * @private
   */
  _scaleDamage(parts, scaling, times, rollData) {
    if ( times <= 0 ) return parts;
    const p0 = new Roll(parts[0], rollData);
    const s = new Roll(scaling, rollData).alter(times);

    // Attempt to simplify by combining like dice terms
    let simplified = false;
    if ( (s.terms[0] instanceof Die) && (s.terms.length === 1) ) {
      const d0 = p0.terms[0];
      const s0 = s.terms[0];
      if ( (d0 instanceof Die) && (d0.faces === s0.faces) && d0.modifiers.equals(s0.modifiers) ) {
        d0.number += s0.number;
        parts[0] = p0.formula;
        simplified = true;
      }
    }

    // Otherwise add to the first part
    if ( !simplified ) {
      parts[0] = `${parts[0]} + ${s.formula}`;
    }
    return parts;
  }

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

  /**
   * Place an attack roll using an item (weapon, feat, power, or equipment)
   * Rely upon the d20Roll logic for the core implementation
   * 
   * @return {Promise<Roll>}   A Promise which resolves to the created Roll instance
   */
  async rollFormula(options={}) {
    if ( !this.data.data.formula ) {
      throw new Error("This Item does not have a formula to roll!");
    }

    // Define Roll Data
    const rollData = this.getRollData();
    if ( options.powerLevel ) rollData.item.level = options.powerLevel;
    const title = `${this.name} - ${game.i18n.localize("SW5E.OtherFormula")}`;

    // Invoke the roll and submit it to chat
    const roll = new Roll(rollData.item.formula, rollData).roll();
    roll.toMessage({
      speaker: ChatMessage.getSpeaker({actor: this.actor}),
      flavor: this.data.data.chatFlavor || title,
      rollMode: game.settings.get("core", "rollMode"),
      messageData: {"flags.sw5e.roll": {type: "other", itemId: this.id }}
    });
    return roll;
  }

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

  /**
   * Use a consumable item, deducting from the quantity or charges of the item.
  * @param {boolean} configureDialog   Whether to show a configuration dialog
   * @return {boolean}                  Whether further execution should be prevented
   * @private
   */
  async _rollConsumable(configureDialog) {
    if ( this.data.type !== "consumable" ) throw new Error("Wrong Item type");
    const itemData = this.data.data;

    // Determine whether to deduct uses of the item
    const uses = itemData.uses || {};
    const autoDestroy = uses.autoDestroy;
    let usesCharges = !!uses.per && (uses.max > 0);
    const recharge = itemData.recharge || {};
    const usesRecharge = !!recharge.value;

    // Display a configuration dialog to confirm the usage
    let placeTemplate = false;
    let consume = uses.autoUse || true;
    if ( configureDialog ) {
      const usage = await AbilityUseDialog.create(this);
      if ( usage === null ) return false;
      consume = Boolean(usage.get("consumeUse"));
      placeTemplate = Boolean(usage.get("placeTemplate"));
    }

    // Update Item data
    if ( consume ) {
      const current = uses.value || 0;
      const remaining = usesCharges ? Math.max(current - 1, 0) : current;
      if ( usesRecharge ) await this.update({"data.recharge.charged": false});
      else {
        const q = itemData.quantity;
        // Case 1, reduce charges
        if ( remaining ) {
          await this.update({"data.uses.value": remaining});
        }
        // Case 2, reduce quantity
        else if ( q > 1 ) {
          await this.update({"data.quantity": q - 1, "data.uses.value": uses.max || 0});
        }
        // Case 3, destroy the item
        else if ( (q <= 1) && autoDestroy ) {
          await this.actor.deleteOwnedItem(this.id);
        }
        // Case 4, reduce item to 0 quantity and 0 charges
        else if ( (q === 1) ) {
          await this.update({"data.quantity": q - 1, "data.uses.value": 0});
        }
        // Case 5, item unusable, display warning and do nothing
        else {
          ui.notifications.warn(game.i18n.format("SW5E.ItemNoUses", {name: this.name}));
        }
      }
    }

    // Maybe initiate template placement workflow
    if ( this.hasAreaTarget && placeTemplate ) {
      const template = AbilityTemplate.fromItem(this);
      if ( template ) template.drawPreview();
      if ( this.owner && this.owner.sheet ) this.owner.sheet.minimize();
    }
    return true;
    }

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

  /**
   * Perform an ability recharge test for an item which uses the d6 recharge mechanic
   * @return {Promise<Roll>}   A Promise which resolves to the created Roll instance
   */
  async rollRecharge() {
    const data = this.data.data;
    if ( !data.recharge.value ) return;

    // Roll the check
    const roll = new Roll("1d6").roll();
    const success = roll.total >= parseInt(data.recharge.value);

    // Display a Chat Message
    const promises = [roll.toMessage({
      flavor: `${game.i18n.format("SW5E.ItemRechargeCheck", {name: this.name})} - ${game.i18n.localize(success ? "SW5E.ItemRechargeSuccess" : "SW5E.ItemRechargeFailure")}`,
      speaker: ChatMessage.getSpeaker({actor: this.actor, token: this.actor.token})
    })];

    // Update the Item data
    if ( success ) promises.push(this.update({"data.recharge.charged": true}));
    return Promise.all(promises).then(() => roll);
  }

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

  /**
   * Roll a Tool Check. Rely upon the d20Roll logic for the core implementation
   * @prarm {Object} options   Roll configuration options provided to the d20Roll function
   * @return {Promise<Roll>}   A Promise which resolves to the created Roll instance
   */
  rollToolCheck(options={}) {
    if ( this.type !== "tool" ) throw "Wrong item type!";

    // Prepare roll data
    let rollData = this.getRollData();
    const parts = [`@mod`, "@prof"];
    const title = `${this.name} - ${game.i18n.localize("SW5E.ToolCheck")}`;

    // Compose the roll data
    const rollConfig = mergeObject({
      parts: parts,
      data: rollData,
      template: "systems/sw5e/templates/chat/tool-roll-dialog.html",
      title: title,
      speaker: ChatMessage.getSpeaker({actor: this.actor}),
      flavor: `${this.name} - ${game.i18n.localize("SW5E.ToolCheck")}`,
      dialogOptions: {
        width: 400,
        top: options.event ? options.event.clientY - 80 : null,
        left: window.innerWidth - 710,
      },
      halflingLucky: this.actor.getFlag("sw5e", "halflingLucky" ) || false,
      messageData: {"flags.sw5e.roll": {type: "tool", itemId: this.id }}
    }, options);
    rollConfig.event = options.event;

    // Call the roll helper utility
    return d20Roll(rollConfig);
  }

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

  /**
   * Prepare a data object which is passed to any Roll formulas which are created related to this Item
   * @private
   */
  getRollData() {
    if ( !this.actor ) return null;
    const rollData = this.actor.getRollData();
    rollData.item = duplicate(this.data.data);

    // Include an ability score modifier if one exists
    const abl = this.abilityMod;
    if ( abl ) {
      const ability = rollData.abilities[abl];
      rollData["mod"] = ability.mod || 0;
    }

    // Include a proficiency score
    const prof = "proficient" in rollData.item ? (rollData.item.proficient || 0) : 1;
    rollData["prof"] = Math.floor(prof * rollData.attributes.prof);
    return rollData;
  }

  /* -------------------------------------------- */
  /*  Chat Message Helpers                        */
  /* -------------------------------------------- */

  static chatListeners(html) {
    html.on('click', '.card-buttons button', this._onChatCardAction.bind(this));
    html.on('click', '.item-name', this._onChatCardToggleContent.bind(this));
  }

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

  /**
   * Handle execution of a chat card action via a click event on one of the card buttons
   * @param {Event} event       The originating click event
   * @returns {Promise}         A promise which resolves once the handler workflow is complete
   * @private
   */
  static async _onChatCardAction(event) {
    event.preventDefault();

    // Extract card data
    const button = event.currentTarget;
    button.disabled = true;
    const card = button.closest(".chat-card");
    const messageId = card.closest(".message").dataset.messageId;
    const message =  game.messages.get(messageId);
    const action = button.dataset.action;

    // Validate permission to proceed with the roll
    const isTargetted = action === "save";
    if ( !( isTargetted || game.user.isGM || message.isAuthor ) ) return;

    // Recover the actor for the chat card
    const actor = this._getChatCardActor(card);
    if ( !actor ) return;

    // Get the Item from stored flag data or by the item ID on the Actor
    const storedData = message.getFlag("sw5e", "itemData");
    const item = storedData ? this.createOwned(storedData, actor) : actor.getOwnedItem(card.dataset.itemId);
    if ( !item ) {
      return ui.notifications.error(game.i18n.format("SW5E.ActionWarningNoItem", {item: card.dataset.itemId, name: actor.name}))
    }
    const powerLevel = parseInt(card.dataset.powerLevel) || null;

    // Handle different actions
    switch ( action ) {
      case "attack":
        await item.rollAttack({event}); break;
      case "damage":
        await item.rollDamage({event, powerLevel}); break;
      case "versatile":
        await item.rollDamage({event, powerLevel, versatile: true}); break;
      case "formula":
        await item.rollFormula({event, powerLevel}); break;
      case "save":
        const targets = this._getChatCardTargets(card);
        for ( let token of targets ) {
          const speaker = ChatMessage.getSpeaker({scene: canvas.scene, token: token});
          await token.actor.rollAbilitySave(button.dataset.ability, { event, speaker });
        }
        break;
      case "toolCheck":
        await item.rollToolCheck({event}); break;
      case "placeTemplate":
        const template = AbilityTemplate.fromItem(item);
        if ( template ) template.drawPreview();
        break;
    }

    // Re-enable the button
    button.disabled = false;
  }

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

  /**
   * Handle toggling the visibility of chat card content when the name is clicked
   * @param {Event} event   The originating click event
   * @private
   */
  static _onChatCardToggleContent(event) {
    event.preventDefault();
    const header = event.currentTarget;
    const card = header.closest(".chat-card");
    const content = card.querySelector(".card-content");
    content.style.display = content.style.display === "none" ? "block" : "none";
  }

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

  /**
   * Get the Actor which is the author of a chat card
   * @param {HTMLElement} card    The chat card being used
   * @return {Actor|null}         The Actor entity or null
   * @private
   */
  static _getChatCardActor(card) {

    // Case 1 - a synthetic actor from a Token
    const tokenKey = card.dataset.tokenId;
    if (tokenKey) {
      const [sceneId, tokenId] = tokenKey.split(".");
      const scene = game.scenes.get(sceneId);
      if (!scene) return null;
      const tokenData = scene.getEmbeddedEntity("Token", tokenId);
      if (!tokenData) return null;
      const token = new Token(tokenData);
      return token.actor;
    }

    // Case 2 - use Actor ID directory
    const actorId = card.dataset.actorId;
    return game.actors.get(actorId) || null;
  }

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

  /**
   * Get the Actor which is the author of a chat card
   * @param {HTMLElement} card    The chat card being used
   * @return {Array.<Actor>}      An Array of Actor entities, if any
   * @private
   */
  static _getChatCardTargets(card) {
    let targets = canvas.tokens.controlled.filter(t => !!t.actor);
    if ( !targets.length && game.user.character ) targets = targets.concat(game.user.character.getActiveTokens());
    if ( !targets.length ) ui.notifications.warn(game.i18n.localize("SW5E.ActionWarningNoToken"));
    return targets;
  }
  
  /* -------------------------------------------- */
  /*  Factory Methods                             */
  /* -------------------------------------------- */

  /**
   * Create a consumable power scroll Item from a power Item.
   * @param {Item5e} power      The power to be made into a scroll
   * @return {Item5e}           The created scroll consumable item
   * @private
   */
  static async createScrollFromPower(power) {

    // Get power data
    const itemData = power instanceof Item5e ? power.data : power;
    const {actionType, description, source, activation, duration, target, range, damage, save, level} = itemData.data;

    // Get scroll data
    const scrollUuid = CONFIG.SW5E.powerScrollIds[level];
    const scrollItem = await fromUuid(scrollUuid);
    const scrollData = scrollItem.data;
    delete scrollData._id;

    // Split the scroll description into an intro paragraph and the remaining details
    const scrollDescription = scrollData.data.description.value;
    const pdel = '</p>';
    const scrollIntroEnd = scrollDescription.indexOf(pdel);
    const scrollIntro = scrollDescription.slice(0, scrollIntroEnd + pdel.length);
    const scrollDetails = scrollDescription.slice(scrollIntroEnd + pdel.length);

    // Create a composite description from the scroll description and the power details
    const desc = `${scrollIntro}<hr/><h3>${itemData.name} (Level ${level})</h3><hr/>${description.value}<hr/><h3>Scroll Details</h3><hr/>${scrollDetails}`;

    // Create the power scroll data
    const powerScrollData = mergeObject(scrollData, {
      name: `${game.i18n.localize("SW5E.PowerScroll")}: ${itemData.name}`,
      img: itemData.img,
      data: {
        "description.value": desc.trim(),
        source,
        actionType,
        activation,
        duration,
        target,
        range,
        damage,
        save,
        level
      }
    });
    return new this(powerScrollData);
  }
}