/**
 * db/registeredKeys.ts — Registered Keys Provisioning (#464)
 *
 * Handles:
 *   - Issuing registered keys with idempotency
 *   - Per-provider and per-account quota enforcement
 *   - Key revocation
 *   - Quota status queries for rate-limiting decisions
 */

import { createHash, randomBytes } from "crypto";
import { v4 as uuidv4 } from "uuid";
import { getDbInstance, rowToCamel } from "./core";

// ─── Types ───────────────────────────────────────────────────────────────────

export interface RegisteredKey {
  id: string;
  keyPrefix: string;
  name: string;
  provider: string;
  accountId: string;
  isActive: boolean;
  revokedAt: string | null;
  expiresAt: string | null;
  idempotencyKey: string | null;
  dailyBudget: number | null;
  hourlyBudget: number | null;
  dailyUsed: number;
  hourlyUsed: number;
  createdAt: string;
  updatedAt: string;
}

export interface RegisteredKeyWithSecret extends RegisteredKey {
  /** Raw key material — only returned once on creation */
  rawKey: string;
}

export interface ProviderKeyLimit {
  provider: string;
  maxActiveKeys: number | null;
  dailyIssueLimit: number | null;
  hourlyIssueLimit: number | null;
  dailyIssued: number;
  hourlyIssued: number;
  updatedAt: string;
}

export interface AccountKeyLimit {
  accountId: string;
  maxActiveKeys: number | null;
  dailyIssueLimit: number | null;
  hourlyIssueLimit: number | null;
  dailyIssued: number;
  hourlyIssued: number;
  updatedAt: string;
}

export interface QuotaCheckResult {
  allowed: boolean;
  errorCode?: string;
  errorMessage?: string;
  provider?: string;
  accountId?: string;
  providerActiveKeys?: number;
  accountActiveKeys?: number;
}

export interface IssueKeyParams {
  name: string;
  provider?: string;
  accountId?: string;
  idempotencyKey?: string;
  expiresAt?: string;
  dailyBudget?: number;
  hourlyBudget?: number;
}

// ─── Helpers ─────────────────────────────────────────────────────────────────

function nowDay(): string {
  return new Date().toISOString().slice(0, 10); // YYYY-MM-DD
}

function nowHour(): string {
  return new Date().toISOString().slice(0, 13); // YYYY-MM-DDTHH
}

function hashKey(raw: string): string {
  if (!raw || typeof raw !== "string") return "";
  return createHash("sha256").update(raw).digest("hex");
}

function generateRawKey(): string {
  // ork_ prefix so users can easily identify these keys
  return "ork_" + randomBytes(24).toString("base64url");
}

/** Reset window counters if the tracking period has changed. */
function maybeResetWindow(
  db: ReturnType<typeof getDbInstance>,
  table: string,
  idField: string,
  idValue: string
): void {
  const today = nowDay();
  const hour = nowHour();

  db.prepare(
    `
    UPDATE ${table}
    SET daily_issued = CASE WHEN last_reset_day <> ? THEN 0 ELSE daily_issued END,
        hourly_issued = CASE WHEN last_reset_hour <> ? THEN 0 ELSE hourly_issued END,
        last_reset_day = ?,
        last_reset_hour = ?
    WHERE ${idField} = ?
  `
  ).run(today, hour, today, hour, idValue);
}

// ─── Public API ──────────────────────────────────────────────────────────────

/**
 * Check if a new registered key can be issued for the given provider/account.
 * Returns { allowed: true } or { allowed: false, errorCode, errorMessage }.
 */
export function checkQuota(provider = "", accountId = ""): QuotaCheckResult {
  const db = getDbInstance();
  const today = nowDay();
  const hour = nowHour();

  // ── provider-level check ──
  if (provider) {
    maybeResetWindow(db, "provider_key_limits", "provider", provider);

    const limits = db
      .prepare("SELECT * FROM provider_key_limits WHERE provider = ?")
      .get(provider) as ProviderKeyLimitRow | undefined;

    if (limits) {
      if (limits.hourly_issue_limit !== null && limits.hourly_issued >= limits.hourly_issue_limit) {
        return {
          allowed: false,
          errorCode: "PROVIDER_QUOTA_EXCEEDED",
          errorMessage: `Hourly issue limit (${limits.hourly_issue_limit}) reached for provider '${provider}'`,
          provider,
        };
      }
      if (limits.daily_issue_limit !== null && limits.daily_issued >= limits.daily_issue_limit) {
        return {
          allowed: false,
          errorCode: "PROVIDER_QUOTA_EXCEEDED",
          errorMessage: `Daily issue limit (${limits.daily_issue_limit}) reached for provider '${provider}'`,
          provider,
        };
      }
      if (limits.max_active_keys !== null) {
        const { activeCount } = db
          .prepare(
            "SELECT COUNT(*) as activeCount FROM registered_keys WHERE provider = ? AND is_active = 1"
          )
          .get(provider) as { activeCount: number };
        if (activeCount >= limits.max_active_keys) {
          return {
            allowed: false,
            errorCode: "MAX_ACTIVE_KEYS_EXCEEDED",
            errorMessage: `Max active keys (${limits.max_active_keys}) reached for provider '${provider}'`,
            provider,
            providerActiveKeys: activeCount,
          };
        }
      }
    }
  }

  // ── account-level check ──
  if (accountId) {
    maybeResetWindow(db, "account_key_limits", "account_id", accountId);

    const limits = db
      .prepare("SELECT * FROM account_key_limits WHERE account_id = ?")
      .get(accountId) as AccountKeyLimitRow | undefined;

    if (limits) {
      if (limits.hourly_issue_limit !== null && limits.hourly_issued >= limits.hourly_issue_limit) {
        return {
          allowed: false,
          errorCode: "ACCOUNT_QUOTA_EXCEEDED",
          errorMessage: `Hourly issue limit (${limits.hourly_issue_limit}) reached for account '${accountId}'`,
          accountId,
        };
      }
      if (limits.daily_issue_limit !== null && limits.daily_issued >= limits.daily_issue_limit) {
        return {
          allowed: false,
          errorCode: "ACCOUNT_QUOTA_EXCEEDED",
          errorMessage: `Daily issue limit (${limits.daily_issue_limit}) reached for account '${accountId}'`,
          accountId,
        };
      }
      if (limits.max_active_keys !== null) {
        const { activeCount } = db
          .prepare(
            "SELECT COUNT(*) as activeCount FROM registered_keys WHERE account_id = ? AND is_active = 1"
          )
          .get(accountId) as { activeCount: number };
        if (activeCount >= limits.max_active_keys) {
          return {
            allowed: false,
            errorCode: "MAX_ACTIVE_KEYS_EXCEEDED",
            errorMessage: `Max active keys (${limits.max_active_keys}) reached for account '${accountId}'`,
            accountId,
            accountActiveKeys: activeCount,
          };
        }
      }
    }
  }

  return { allowed: true };
}

/**
 * Issue a new registered key.
 * Returns the key with rawKey (only on creation) or null if idempotency_key already exists.
 */
export function issueRegisteredKey(
  params: IssueKeyParams
): RegisteredKeyWithSecret | { idempotencyConflict: true; existing: RegisteredKey } {
  const db = getDbInstance();
  const {
    name,
    provider = "",
    accountId = "",
    idempotencyKey,
    expiresAt,
    dailyBudget,
    hourlyBudget,
  } = params;

  // ── idempotency check ──
  if (idempotencyKey) {
    const existing = db
      .prepare("SELECT * FROM registered_keys WHERE idempotency_key = ?")
      .get(idempotencyKey) as RegisteredKeyRow | undefined;
    if (existing) {
      return {
        idempotencyConflict: true,
        existing: rowToCamel(existing) as unknown as RegisteredKey,
      };
    }
  }

  const rawKey = generateRawKey();
  const id = uuidv4();
  const keyHash = hashKey(rawKey);
  const keyPrefix = rawKey.slice(0, 12); // "ork_" + 8 chars

  db.prepare(
    `
    INSERT INTO registered_keys
      (id, key, key_prefix, name, provider, account_id, idempotency_key, expires_at, daily_budget, hourly_budget, last_reset_day, last_reset_hour)
    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
  `
  ).run(
    id,
    keyHash,
    keyPrefix,
    name,
    provider,
    accountId,
    idempotencyKey ?? null,
    expiresAt ?? null,
    dailyBudget ?? null,
    hourlyBudget ?? null,
    nowDay(),
    nowHour()
  );

  // Increment provider/account issuance counters
  if (provider) {
    maybeResetWindow(db, "provider_key_limits", "provider", provider);
    db.prepare(
      `
      INSERT INTO provider_key_limits (provider, daily_issued, hourly_issued, last_reset_day, last_reset_hour)
      VALUES (?, 1, 1, ?, ?)
      ON CONFLICT(provider) DO UPDATE SET
        daily_issued = daily_issued + 1,
        hourly_issued = hourly_issued + 1,
        updated_at = datetime('now')
    `
    ).run(provider, nowDay(), nowHour());
  }
  if (accountId) {
    maybeResetWindow(db, "account_key_limits", "account_id", accountId);
    db.prepare(
      `
      INSERT INTO account_key_limits (account_id, daily_issued, hourly_issued, last_reset_day, last_reset_hour)
      VALUES (?, 1, 1, ?, ?)
      ON CONFLICT(account_id) DO UPDATE SET
        daily_issued = daily_issued + 1,
        hourly_issued = hourly_issued + 1,
        updated_at = datetime('now')
    `
    ).run(accountId, nowDay(), nowHour());
  }

  const created = db
    .prepare("SELECT * FROM registered_keys WHERE id = ?")
    .get(id) as RegisteredKeyRow;
  return { ...(rowToCamel(created) as unknown as RegisteredKey), rawKey };
}

/**
 * Get a registered key by ID (without the raw key — only prefix is returned).
 */
export function getRegisteredKey(id: string): RegisteredKey | null {
  const db = getDbInstance();
  const row = db.prepare("SELECT * FROM registered_keys WHERE id = ?").get(id) as
    | RegisteredKeyRow
    | undefined;
  return row ? (rowToCamel(row) as unknown as RegisteredKey) : null;
}

/**
 * List all registered keys (optionally filtered by provider/accountId).
 */
export function listRegisteredKeys(
  opts: { provider?: string; accountId?: string } = {}
): RegisteredKey[] {
  const db = getDbInstance();
  let sql = "SELECT * FROM registered_keys WHERE 1=1";
  const args: string[] = [];
  if (opts.provider) {
    sql += " AND provider = ?";
    args.push(opts.provider);
  }
  if (opts.accountId) {
    sql += " AND account_id = ?";
    args.push(opts.accountId);
  }
  sql += " ORDER BY created_at DESC LIMIT 500";
  const rows = db.prepare(sql).all(...args) as RegisteredKeyRow[];
  return rows.map((r) => rowToCamel(r) as unknown as RegisteredKey);
}

/**
 * Revoke a registered key by ID.
 */
export function revokeRegisteredKey(id: string): boolean {
  const db = getDbInstance();
  const result = db
    .prepare(
      `
    UPDATE registered_keys
    SET is_active = 0, revoked_at = datetime('now'), updated_at = datetime('now')
    WHERE id = ? AND is_active = 1
  `
    )
    .run(id);
  return result.changes > 0;
}

/**
 * Validate a raw registered key against stored hashes.
 * Returns the key metadata if valid, null otherwise.
 */
export function validateRegisteredKey(rawKey: string): RegisteredKey | null {
  const db = getDbInstance();
  const hash = hashKey(rawKey);
  const row = db
    .prepare(
      `
    SELECT * FROM registered_keys
    WHERE key = ? AND is_active = 1
      AND (expires_at IS NULL OR expires_at > datetime('now'))
  `
    )
    .get(hash) as RegisteredKeyRow | undefined;
  if (!row) return null;

  // Auto-reset budget windows if needed
  const today = nowDay();
  const hour = nowHour();
  if (row.last_reset_day !== today || row.last_reset_hour !== hour) {
    db.prepare(
      `
      UPDATE registered_keys
      SET daily_used = CASE WHEN last_reset_day <> ? THEN 0 ELSE daily_used END,
          hourly_used = CASE WHEN last_reset_hour <> ? THEN 0 ELSE hourly_used END,
          last_reset_day = ?, last_reset_hour = ?
      WHERE id = ?
    `
    ).run(today, hour, today, hour, row.id);
  }

  // Budget check
  if (row.daily_budget !== null && row.daily_used >= row.daily_budget) return null;
  if (row.hourly_budget !== null && row.hourly_used >= row.hourly_budget) return null;

  return rowToCamel(row) as unknown as RegisteredKey;
}

/**
 * Increment usage counters for a registered key (called by request pipeline).
 */
export function incrementRegisteredKeyUsage(id: string): void {
  const db = getDbInstance();
  db.prepare(
    `
    UPDATE registered_keys
    SET daily_used = daily_used + 1, hourly_used = hourly_used + 1, updated_at = datetime('now')
    WHERE id = ?
  `
  ).run(id);
}

// ─── Provider / Account Limit Management ──────────────────────────────────────

export function setProviderKeyLimit(
  provider: string,
  limits: Partial<Omit<ProviderKeyLimit, "provider" | "dailyIssued" | "hourlyIssued" | "updatedAt">>
): void {
  const db = getDbInstance();
  db.prepare(
    `
    INSERT INTO provider_key_limits (provider, max_active_keys, daily_issue_limit, hourly_issue_limit, last_reset_day, last_reset_hour)
    VALUES (?, ?, ?, ?, ?, ?)
    ON CONFLICT(provider) DO UPDATE SET
      max_active_keys = excluded.max_active_keys,
      daily_issue_limit = excluded.daily_issue_limit,
      hourly_issue_limit = excluded.hourly_issue_limit,
      updated_at = datetime('now')
  `
  ).run(
    provider,
    limits.maxActiveKeys ?? null,
    limits.dailyIssueLimit ?? null,
    limits.hourlyIssueLimit ?? null,
    nowDay(),
    nowHour()
  );
}

export function setAccountKeyLimit(
  accountId: string,
  limits: Partial<Omit<AccountKeyLimit, "accountId" | "dailyIssued" | "hourlyIssued" | "updatedAt">>
): void {
  const db = getDbInstance();
  db.prepare(
    `
    INSERT INTO account_key_limits (account_id, max_active_keys, daily_issue_limit, hourly_issue_limit, last_reset_day, last_reset_hour)
    VALUES (?, ?, ?, ?, ?, ?)
    ON CONFLICT(account_id) DO UPDATE SET
      max_active_keys = excluded.max_active_keys,
      daily_issue_limit = excluded.daily_issue_limit,
      hourly_issue_limit = excluded.hourly_issue_limit,
      updated_at = datetime('now')
  `
  ).run(
    accountId,
    limits.maxActiveKeys ?? null,
    limits.dailyIssueLimit ?? null,
    limits.hourlyIssueLimit ?? null,
    nowDay(),
    nowHour()
  );
}

export function getProviderKeyLimit(provider: string): ProviderKeyLimit | null {
  const db = getDbInstance();
  const row = db.prepare("SELECT * FROM provider_key_limits WHERE provider = ?").get(provider) as
    | ProviderKeyLimitRow
    | undefined;
  return row ? (rowToCamel(row) as unknown as ProviderKeyLimit) : null;
}

export function getAccountKeyLimit(accountId: string): AccountKeyLimit | null {
  const db = getDbInstance();
  const row = db.prepare("SELECT * FROM account_key_limits WHERE account_id = ?").get(accountId) as
    | AccountKeyLimitRow
    | undefined;
  return row ? (rowToCamel(row) as unknown as AccountKeyLimit) : null;
}

// ─── Internal types (raw DB rows) ─────────────────────────────────────────────

interface RegisteredKeyRow {
  id: string;
  key: string;
  key_prefix: string;
  name: string;
  provider: string;
  account_id: string;
  is_active: number;
  revoked_at: string | null;
  expires_at: string | null;
  idempotency_key: string | null;
  daily_budget: number | null;
  hourly_budget: number | null;
  daily_used: number;
  hourly_used: number;
  last_reset_day: string;
  last_reset_hour: string;
  created_at: string;
  updated_at: string;
}

interface ProviderKeyLimitRow {
  provider: string;
  max_active_keys: number | null;
  daily_issue_limit: number | null;
  hourly_issue_limit: number | null;
  daily_issued: number;
  hourly_issued: number;
  last_reset_day: string;
  last_reset_hour: string;
  updated_at: string;
}

interface AccountKeyLimitRow {
  account_id: string;
  max_active_keys: number | null;
  daily_issue_limit: number | null;
  hourly_issue_limit: number | null;
  daily_issued: number;
  hourly_issued: number;
  last_reset_day: string;
  last_reset_hour: string;
  updated_at: string;
}