export type EnemyAttackAnimation = "attack" | "cast";
export type EnemyAttackDelivery = "melee" | "projectile" | "area";
export type EnemyAttackTarget =
  | "primary"
  | "random-party"
  | "nearby-party"
  | "self"
  | "lowest-health-friendly";
export type EnemyDamageSchool =
  | "physical"
  | "arcane"
  | "fire"
  | "frost"
  | "nature"
  | "shadow"
  | "holy";

export type EnemyControlMechanic = "fear" | "sleep" | "root" | "stun" | "silence";

export type EnemyAbilityEffect =
  | { readonly kind: "damage"; readonly multiplier: number }
  | { readonly kind: "heal"; readonly multiplier: number }
  | {
    readonly kind: "aura";
    readonly aura: string;
    readonly durationMs: number;
    readonly magnitude?: number;
  }
  | {
    readonly kind: "control";
    readonly mechanic: EnemyControlMechanic;
    readonly durationMs: number;
  }
  | { readonly kind: "transform"; readonly form: string }
  | { readonly kind: "summon"; readonly creatureEntry: number; readonly count: number }
  | { readonly kind: "call-for-help"; readonly radius: number }
  | { readonly kind: "encounter-event"; readonly eventId: string };

export type EnemyAbilityCondition =
  | { readonly kind: "in-combat" }
  | {
    readonly kind: "self-health-percent";
    readonly minimum: number;
    readonly maximum: number;
  }
  | {
    readonly kind: "friendly-missing-health";
    readonly amount: number;
    readonly range: number;
  }
  | {
    readonly kind: "encounter-state";
    readonly encounterId: string;
    readonly states: readonly string[];
  };

export interface EnemyAbilitySource {
  readonly entry: number;
  readonly sourceType: number;
  readonly rowId: number;
  readonly eventType: number;
  readonly actionType: number;
  readonly targetType: number;
  readonly comment: string;
}

export interface EnemyAttackDefinition {
  readonly id: string;
  readonly name: string;
  readonly spellId?: number;
  readonly delivery: EnemyAttackDelivery;
  readonly target: EnemyAttackTarget;
  readonly school: EnemyDamageSchool;
  readonly animation: EnemyAttackAnimation;
  /** Zero keeps the legacy instant-execution behavior. */
  readonly castTimeMs?: number;
  /** Casts are interruptible unless explicitly disabled. */
  readonly interruptible?: boolean;
  readonly range: number;
  readonly cooldownMs: number;
  readonly initialCooldownMs?: readonly [minimum: number, maximum: number];
  readonly repeatCooldownMs?: readonly [minimum: number, maximum: number];
  readonly maximumCasts?: number;
  readonly damageMultiplier: number;
  readonly radius?: number;
  readonly effect?: EnemyAbilityEffect;
  readonly condition?: EnemyAbilityCondition;
  readonly source?: EnemyAbilitySource;
}

export interface EnemyCombatDefinition {
  readonly serverEntry?: number;
  readonly level?: number;
  readonly healthMultiplier?: number;
  readonly damageMultiplier?: number;
  readonly moveSpeed?: number;
  readonly aggroRange?: number;
  readonly leashRange?: number;
  readonly attacks: readonly EnemyAttackDefinition[];
}

export const DEFAULT_ENEMY_ATTACK: EnemyAttackDefinition = Object.freeze({
  id: "basic-attack",
  name: "Basic Attack",
  delivery: "melee",
  target: "primary",
  school: "physical",
  animation: "attack",
  range: 4.5,
  cooldownMs: 1_900,
  damageMultiplier: 1,
});

function finiteAtLeast(value: number | undefined, fallback: number, minimum: number): number {
  return Number.isFinite(value) ? Math.max(minimum, value!) : fallback;
}

function normalizeCooldownRange(
  value: readonly [number, number] | undefined,
  fallback: number,
  minimum: number,
): readonly [number, number] {
  const lower = finiteAtLeast(value?.[0], fallback, minimum);
  const upper = finiteAtLeast(value?.[1], lower, lower);
  return Object.freeze([Math.round(lower), Math.round(upper)]);
}

export function normalizeEnemyAttack(
  value: EnemyAttackDefinition,
  fallback: EnemyAttackDefinition = DEFAULT_ENEMY_ATTACK,
): EnemyAttackDefinition {
  const cooldownMs = Math.round(finiteAtLeast(value.cooldownMs, fallback.cooldownMs, 1));
  const inferredCastTimeMs = value.castTimeMs === undefined && value.animation === "cast"
    ? (fallback.castTimeMs ?? 1_500)
    : (fallback.castTimeMs ?? 0);
  return Object.freeze({
    id: value.id.trim() || fallback.id,
    name: value.name.trim() || fallback.name,
    ...(Number.isInteger(value.spellId) && value.spellId! > 0
      ? { spellId: value.spellId }
      : {}),
    delivery: value.delivery,
    target: value.target,
    school: value.school,
    animation: value.animation,
    castTimeMs: Math.round(finiteAtLeast(value.castTimeMs, inferredCastTimeMs, 0)),
    interruptible: value.interruptible ?? fallback.interruptible ?? true,
    range: finiteAtLeast(value.range, fallback.range, 0),
    cooldownMs,
    ...(value.initialCooldownMs
      ? { initialCooldownMs: normalizeCooldownRange(value.initialCooldownMs, cooldownMs, 0) }
      : {}),
    ...(value.repeatCooldownMs
      ? { repeatCooldownMs: normalizeCooldownRange(value.repeatCooldownMs, cooldownMs, 1) }
      : {}),
    ...(Number.isInteger(value.maximumCasts) && value.maximumCasts! > 0
      ? { maximumCasts: value.maximumCasts }
      : {}),
    damageMultiplier: finiteAtLeast(value.damageMultiplier, fallback.damageMultiplier, 0),
    ...(value.radius !== undefined
      ? { radius: finiteAtLeast(value.radius, 0, 0) }
      : {}),
    ...(value.effect ? { effect: value.effect } : {}),
    ...(value.condition ? { condition: value.condition } : {}),
    ...(value.source ? { source: value.source } : {}),
  });
}

export function normalizeEnemyAttacks(
  attacks: readonly EnemyAttackDefinition[] | undefined,
  fallback: EnemyAttackDefinition = DEFAULT_ENEMY_ATTACK,
): readonly EnemyAttackDefinition[] {
  const source = attacks?.length ? attacks : [fallback];
  const normalized = source.map((attack) => normalizeEnemyAttack(attack, fallback));
  const seen = new Set<string>();
  return Object.freeze(normalized.filter((attack) => {
    if (seen.has(attack.id)) return false;
    seen.add(attack.id);
    return true;
  }));
}

export function maximumEnemyAttackRange(attacks: readonly EnemyAttackDefinition[]): number {
  return attacks.reduce((maximum, attack) => Math.max(maximum, attack.range), 0);
}