import { BASE_CLASS_IDS, ROM_CLASS_IDS } from "../app/characterCatalog";
import { partyRolesForClass, type PartyRole } from "./partyRoles";
import {
  SPECIALIZATION_DEFINITIONS,
  romGearProfile,
  type SpecializationDefinition,
} from "./specializationCatalog";

export type CompanionSpecReadinessStatus = "ready" | "beta" | "needs-testing";

export interface CompanionSpecReadinessPolicy {
  readonly schemaVersion: 1;
  readonly statuses: Readonly<Record<string, CompanionSpecReadinessStatus>>;
}

export interface PublishedCompanionSpecReadinessPolicy {
  readonly revision: number;
  readonly updatedAt: number | null;
  readonly updatedBy?: string | null;
  readonly config: CompanionSpecReadinessPolicy;
}

export const READY_COMPANION_SPECIALIZATION_IDS = Object.freeze([
  "warrior:protection",
  "priest:discipline",
  "hunter:marksmanship",
  "mage:fire",
  "rogue:assassination",
] as const);

const CLASSIC_CLASS_IDS = new Set<string>(BASE_CLASS_IDS);
const READY_IDS = new Set<string>(READY_COMPANION_SPECIALIZATION_IDS);
const VALID_STATUSES = new Set<CompanionSpecReadinessStatus>(["ready", "beta", "needs-testing"]);

export const WOW_COMPANION_SPECIALIZATIONS: readonly SpecializationDefinition[] = Object.freeze(
  SPECIALIZATION_DEFINITIONS.filter((definition) => CLASSIC_CLASS_IDS.has(definition.classId)),
);

/**
 * Complete certification catalog. CoA specializations and RoM class/role
 * profiles are visible as Needs Testing, but remain outside the publishable
 * WoW policy until their companion implementations enter certification.
 */
export const COMPANION_READINESS_SPECIALIZATIONS: readonly SpecializationDefinition[] = Object.freeze([
  ...SPECIALIZATION_DEFINITIONS,
  ...ROM_CLASS_IDS.flatMap((classId) => partyRolesForClass(classId).map((role) => (
    romGearProfile(classId, role)
  ))),
]);

const WOW_SPECIALIZATION_IDS = new Set(WOW_COMPANION_SPECIALIZATIONS.map((definition) => definition.id));

export const DEFAULT_COMPANION_SPEC_READINESS_POLICY: CompanionSpecReadinessPolicy = Object.freeze({
  schemaVersion: 1,
  statuses: Object.freeze(Object.fromEntries(
    WOW_COMPANION_SPECIALIZATIONS.map((definition) => [
      definition.id,
      (READY_IDS.has(definition.id) ? "ready" : "needs-testing") as CompanionSpecReadinessStatus,
    ]),
  )),
});

function invalid(message: string): Error {
  return new Error(message);
}

export function readinessStatusFor(
  specializationId: string | null | undefined,
  policy: CompanionSpecReadinessPolicy = DEFAULT_COMPANION_SPEC_READINESS_POLICY,
): CompanionSpecReadinessStatus {
  if (!specializationId || !WOW_SPECIALIZATION_IDS.has(specializationId)) return "needs-testing";
  return policy.statuses[specializationId] ?? "needs-testing";
}

export function validateReadyRoleCoverage(policy: CompanionSpecReadinessPolicy): void {
  const readyByRole = (role: PartyRole) => WOW_COMPANION_SPECIALIZATIONS.filter((definition) => (
    definition.role === role && readinessStatusFor(definition.id, policy) === "ready"
  ));
  if (readyByRole("tank").length < 1) throw invalid("At least one tank specialization must be Ready.");
  if (readyByRole("healer").length < 1) throw invalid("At least one healer specialization must be Ready.");
  if (new Set(readyByRole("damage").map((definition) => definition.id)).size < 3) {
    throw invalid("At least three distinct damage specializations must be Ready.");
  }
}

export function normalizeCompanionSpecReadinessPolicy(value: unknown): CompanionSpecReadinessPolicy {
  if (!value || typeof value !== "object" || Array.isArray(value)) {
    throw invalid("Companion readiness policy must be an object.");
  }
  const input = value as Partial<CompanionSpecReadinessPolicy>;
  if (input.schemaVersion !== 1) throw invalid("Companion readiness policy schemaVersion must be 1.");
  if (!input.statuses || typeof input.statuses !== "object" || Array.isArray(input.statuses)) {
    throw invalid("Companion readiness statuses are required.");
  }
  for (const [specializationId, status] of Object.entries(input.statuses)) {
    if (!WOW_SPECIALIZATION_IDS.has(specializationId)) {
      throw invalid(`Unknown WoW specialization: ${specializationId}.`);
    }
    if (!VALID_STATUSES.has(status as CompanionSpecReadinessStatus)) {
      throw invalid(`Invalid readiness status for ${specializationId}.`);
    }
  }
  const policy: CompanionSpecReadinessPolicy = Object.freeze({
    schemaVersion: 1,
    statuses: Object.freeze(Object.fromEntries(WOW_COMPANION_SPECIALIZATIONS.map((definition) => [
      definition.id,
      (input.statuses as Readonly<Record<string, CompanionSpecReadinessStatus>>)[definition.id] ?? "needs-testing",
    ]))),
  });
  validateReadyRoleCoverage(policy);
  return policy;
}

export function companionSpecializationsForPolicy(
  policy: CompanionSpecReadinessPolicy,
  includeBetaSpecs: boolean,
  role?: PartyRole,
): readonly SpecializationDefinition[] {
  return WOW_COMPANION_SPECIALIZATIONS.filter((definition) => {
    if (role && definition.role !== role) return false;
    const status = readinessStatusFor(definition.id, policy);
    return status === "ready" || (includeBetaSpecs && status === "beta");
  });
}

export function cloneDefaultCompanionSpecReadinessPolicy(): CompanionSpecReadinessPolicy {
  return JSON.parse(JSON.stringify(DEFAULT_COMPANION_SPEC_READINESS_POLICY)) as CompanionSpecReadinessPolicy;
}

export function companionSpecReadinessFromCache(value: string | null): PublishedCompanionSpecReadinessPolicy {
  try {
    const parsed = JSON.parse(value ?? "null") as Partial<PublishedCompanionSpecReadinessPolicy> | null;
    if (!parsed || !Number.isInteger(parsed.revision)) throw new Error("missing cache");
    return {
      revision: parsed.revision!,
      updatedAt: parsed.updatedAt ?? null,
      updatedBy: parsed.updatedBy ?? null,
      config: normalizeCompanionSpecReadinessPolicy(parsed.config),
    };
  } catch {
    return { revision: 0, updatedAt: null, updatedBy: null, config: DEFAULT_COMPANION_SPEC_READINESS_POLICY };
  }
}