import { creatureTemplateReference } from "./azerothCoreReference";
import {
  ENEMY_DUAL_WIELD_FIRST_SWING_DELAY_FRACTION,
  ENEMY_DUAL_WIELD_SIMULTANEOUS_SWING_DELAY_MS,
  ENEMY_DUAL_WIELD_WHITE_MISS_PENALTY_PERCENT,
} from "./enemyExtraAttacks";

/** AzerothCore CREATURE_FLAG_EXTRA_USE_OFFHAND_ATTACK. */
export const CREATURE_FLAG_EXTRA_USE_OFFHAND_ATTACK = 0x0000_0800;

/** AzerothCore ITEM_CLASS_WEAPON, also stored in the client Item.dbc Class field. */
export const ENEMY_OFFHAND_ITEM_CLASS_WEAPON = 2;

/** Pinned world row carrying creature_template.flags_extra. */
export const ENEMY_AUTOMATIC_OFFHAND_WORLD_SOURCE = Object.freeze({
  repository: "https://github.com/azerothcore/azerothcore-wotlk",
  commit: "4d9d1d4b5723e819c5c390f6ca1177283dbfb8e3",
  table: "creature_template",
  path: "data/sql/base/db_world/creature_template.sql",
  sha256: "0066e4fd35b809986dd325487515087f5a95f4ffe50ea03846c8d8bf5196870a",
});

/** Byte-identical local WotLK client/server Item.dbc files used for item Class lookups. */
export const ENEMY_AUTOMATIC_OFFHAND_ITEM_SOURCE = Object.freeze({
  path: "../wow335a/Data/patch-A.MPQ/DBFilesClient/Item.dbc",
  sha256: "22061a811523790ddd2ee95b36ade2ac6e0c79a8b3121324d32a639acf50567f",
  classField: 1,
});

export interface EnemyAutomaticOffhandContract {
  readonly entry: number;
  readonly name: string;
  readonly source: "creature-template-flag" | "auto-offhand-weapon";
  /** `enabled` bypasses the equipment check; `auto` requires a valid weapon item. */
  readonly dualWieldMode: "enabled" | "auto";
  readonly requiresEquippedWeapon: boolean;
  readonly attackType: "offhand";
  /** Creature::CalculateMinMaxDamage uses the creature-generated hand range and AP formula. */
  readonly baseDamageFrom: "same-creature-template-offhand-range-and-ap-formula";
  /** UNIT_MOD_DAMAGE_OFFHAND TOTAL_PCT starts at 0.5 in the pinned core source. */
  readonly damageMultiplier: 0.5;
  /** Ordinary white swings add 19 points when an offhand channel is available. */
  readonly whiteSwingMissPenaltyPercent: typeof ENEMY_DUAL_WIELD_WHITE_MISS_PENALTY_PERCENT;
  readonly attackTimeFrom: "creature-template-base-attack-time";
  readonly independentSwingTimer: true;
  readonly firstSwingDelayFractionOnEngage: typeof ENEMY_DUAL_WIELD_FIRST_SWING_DELAY_FRACTION;
  readonly simultaneousSwingDelayMs: typeof ENEMY_DUAL_WIELD_SIMULTANEOUS_SWING_DELAY_MS;
}

function makeContract(input: {
  entry: number;
  name: string;
  source: EnemyAutomaticOffhandContract["source"];
  dualWieldMode: EnemyAutomaticOffhandContract["dualWieldMode"];
  requiresEquippedWeapon: boolean;
}): EnemyAutomaticOffhandContract {
  return Object.freeze({
    ...input,
    attackType: "offhand",
    baseDamageFrom: "same-creature-template-offhand-range-and-ap-formula",
    damageMultiplier: 0.5,
    whiteSwingMissPenaltyPercent: ENEMY_DUAL_WIELD_WHITE_MISS_PENALTY_PERCENT,
    attackTimeFrom: "creature-template-base-attack-time",
    independentSwingTimer: true,
    firstSwingDelayFractionOnEngage: ENEMY_DUAL_WIELD_FIRST_SWING_DELAY_FRACTION,
    simultaneousSwingDelayMs: ENEMY_DUAL_WIELD_SIMULTANEOUS_SWING_DELAY_MS,
  });
}

/**
 * Resolves only the pinned creature-template USE_OFFHAND_ATTACK bit. This is
 * an intrinsic creature capability, set by Creature::InitEntry/UpdateEntry;
 * it survives combat, evade, and death state resets while the creature entry
 * remains the same.
 */
export function enemyFlagDrivenOffhandContract(entry: number): EnemyAutomaticOffhandContract | undefined {
  if (!Number.isSafeInteger(entry) || entry <= 0) return undefined;
  const template = creatureTemplateReference(entry);
  const flagsExtra = template?.flagsExtra;
  if (!template || !Number.isSafeInteger(flagsExtra) || flagsExtra! < 0 || flagsExtra! > 0xffff_ffff
    || (flagsExtra! & CREATURE_FLAG_EXTRA_USE_OFFHAND_ATTACK) === 0) return undefined;

  return makeContract({
    entry: template.entry,
    name: template.name,
    source: "creature-template-flag",
    dualWieldMode: "enabled",
    requiresEquippedWeapon: false,
  });
}

/**
 * Resolves the default AUTO-mode offhand gate used by Creature::HasWeapon.
 * `itemClass` must come from a successfully resolved client/server item row;
 * class WEAPON (2) is the entire core gate after source virtual-item validation.
 * Callers must resolve the pinned spawn selector and equipment set; model or
 * display IDs and the selector itself are never treated as item IDs.
 */
export function enemyAutoEquippedOffhandContract(input: {
  readonly entry: number;
  readonly name?: string;
  readonly offhandItemId: number;
  readonly offhandItemClass: number | null | undefined;
}): EnemyAutomaticOffhandContract | undefined {
  if (!Number.isSafeInteger(input.entry) || input.entry <= 0
    || !Number.isSafeInteger(input.offhandItemId) || input.offhandItemId <= 0
    || input.offhandItemClass !== ENEMY_OFFHAND_ITEM_CLASS_WEAPON) return undefined;

  const template = creatureTemplateReference(input.entry);
  if (!template) return undefined;
  return makeContract({
    entry: input.entry,
    name: input.name?.trim() || template.name,
    source: "auto-offhand-weapon",
    dualWieldMode: "auto",
    requiresEquippedWeapon: true,
  });
}