import type { PoolConnection, ResultSetHeader, RowDataPacket } from 'mysql2/promise';
import type { AccessProfile } from '../auth/rbac-repository.js';
import type { MySqlPool } from '../db/mysql.js';
import type { OrderActor } from './order-state-repository.js';

type PricingPolicy = 'CURRENT' | 'LOCKED';
type AdjustableStatus = 'PENDING_PAYMENT' | 'PAID' | 'RESERVED' | 'IN_PROGRESS';

interface OrderRow extends RowDataPacket {
  id: string;
  storeId: string;
  roomId: string;
  status: AdjustableStatus;
  startAt: Date;
  endAt: Date;
  totalAmountCents: number;
  adjustmentAmountCents: number;
  cancellationCutoffMinutes: number;
  cancellationFeeBps: number;
}
interface RoomRow extends RowDataPacket {
  id: string;
  storeId: string;
  basePriceCents: number;
  weekdayPriceCents: number;
  holidayPriceCents: number;
  timezone: string;
  operationalStatus: string;
  configurationStatus: string;
}
interface SnapshotRow extends RowDataPacket { unitPriceCents: number }
interface DuplicateRow extends RowDataPacket {
  id: string;
  adjustmentType: string;
  amountDeltaCents: number;
}

export class OrderManagementError extends Error {
  constructor(public readonly code: string) { super(code); }
}

export class OrderManagementRepository {
  constructor(private readonly pool: MySqlPool) {}

  async renew(actor: OrderActor, orderId: string, input: {
    endAt: Date; pricingPolicy: PricingPolicy; reason: string;
  }) {
    return this.transaction(async (connection) => {
      const order = await this.loadOrder(connection, actor.tenantId, orderId);
      this.assertManager(actor.access, order.storeId);
      const duplicate = await this.duplicate(connection, actor, orderId);
      if (duplicate) return this.duplicateResult(orderId, duplicate);
      if (!['PAID', 'RESERVED', 'IN_PROGRESS'].includes(order.status)) {
        throw new OrderManagementError('ORDER_RENEW_STATUS_INVALID');
      }
      if (input.endAt <= order.endAt) throw new OrderManagementError('ORDER_RENEW_END_INVALID');
      await this.lockRooms(connection, actor.tenantId, [order.roomId]);
      await this.assertAvailable(
        connection, actor.tenantId, order.roomId, order.endAt, input.endAt, orderId
      );
      const unitPrice = await this.resolveUnitPrice(
        connection, actor.tenantId, order, input.pricingPolicy
      );
      const amountDeltaCents = Math.ceil(
        (input.endAt.getTime() - order.endAt.getTime()) / 3600000
      ) * unitPrice;
      await connection.execute(
        `UPDATE qipai_orders
         SET end_at = ?, total_amount_cents = total_amount_cents + ?,
             adjustment_amount_cents = adjustment_amount_cents + ?
         WHERE tenant_id = ? AND id = ?`,
        [input.endAt, amountDeltaCents, amountDeltaCents, actor.tenantId, orderId]
      );
      await connection.execute(
        `UPDATE qipai_room_reservations
         SET ends_at = ?, expires_at = GREATEST(expires_at, ?)
         WHERE tenant_id = ? AND order_id = ?`,
        [input.endAt, input.endAt, actor.tenantId, orderId]
      );
      return this.record(connection, actor, order, 'RENEW', input.reason, {
        endAt: order.endAt
      }, { endAt: input.endAt, pricingPolicy: input.pricingPolicy }, amountDeltaCents);
    });
  }

  async customerRenew(actor: OrderActor, orderId: string, input: {
    endAt: Date; pricingPolicy: PricingPolicy; reason: string;
  }) {
    return this.renewForActor(actor, orderId, input, async (connection, order) => {
      await this.assertOwner(connection, actor.tenantId, order.id, actor.userId);
    });
  }

  async changeRoom(actor: OrderActor, orderId: string, input: {
    roomId: string; reason: string;
  }) {
    return this.transaction(async (connection) => {
      const order = await this.loadOrder(connection, actor.tenantId, orderId);
      this.assertManager(actor.access, order.storeId);
      const duplicate = await this.duplicate(connection, actor, orderId);
      if (duplicate) return this.duplicateResult(orderId, duplicate);
      if (!['PENDING_PAYMENT', 'PAID', 'RESERVED', 'IN_PROGRESS'].includes(order.status)) {
        throw new OrderManagementError('ORDER_ROOM_CHANGE_STATUS_INVALID');
      }
      if (input.roomId === order.roomId) throw new OrderManagementError('ORDER_ROOM_UNCHANGED');
      await this.lockRooms(connection, actor.tenantId, [order.roomId, input.roomId]);
      const target = await this.loadRoom(connection, actor.tenantId, input.roomId);
      this.assertManager(actor.access, target.storeId);
      await this.assertAvailable(
        connection, actor.tenantId, target.id, order.startAt, order.endAt, orderId
      );
      const oldRoom = await this.loadRoom(connection, actor.tenantId, order.roomId);
      const hours = Math.ceil((order.endAt.getTime() - order.startAt.getTime()) / 3600000);
      const amountDeltaCents = hours * (target.basePriceCents - oldRoom.basePriceCents);
      await connection.execute(
        `UPDATE qipai_orders
         SET store_id = ?, room_id = ?,
             total_amount_cents = GREATEST(0, total_amount_cents + ?),
             adjustment_amount_cents = adjustment_amount_cents + ?
         WHERE tenant_id = ? AND id = ?`,
        [target.storeId, target.id, amountDeltaCents, amountDeltaCents,
          actor.tenantId, orderId]
      );
      await connection.execute(
        `UPDATE qipai_room_reservations SET room_id = ?
         WHERE tenant_id = ? AND order_id = ?`,
        [target.id, actor.tenantId, orderId]
      );
      return this.record(connection, actor, order, 'CHANGE_ROOM', input.reason, {
        storeId: order.storeId, roomId: order.roomId
      }, { storeId: target.storeId, roomId: target.id }, amountDeltaCents);
    });
  }

  async customerChangeRoom(actor: OrderActor, orderId: string, input: {
    roomId: string; reason: string;
  }) {
    return this.changeRoomForActor(actor, orderId, input, async (connection, order, target) => {
      await this.assertOwner(connection, actor.tenantId, order.id, actor.userId);
      if (target.storeId !== order.storeId) {
        throw new OrderManagementError('ORDER_ROOM_CHANGE_STORE_INVALID');
      }
    });
  }

  async adjustTime(actor: OrderActor, orderId: string, input: {
    startAt?: Date; endAt?: Date; reason: string;
  }) {
    return this.transaction(async (connection) => {
      const order = await this.loadOrder(connection, actor.tenantId, orderId);
      this.assertManager(actor.access, order.storeId);
      const duplicate = await this.duplicate(connection, actor, orderId);
      if (duplicate) return this.duplicateResult(orderId, duplicate);
      const startAt = input.startAt ?? order.startAt;
      const endAt = input.endAt ?? order.endAt;
      if (endAt <= startAt) throw new OrderManagementError('ORDER_TIME_WINDOW_INVALID');
      await this.lockRooms(connection, actor.tenantId, [order.roomId]);
      await this.assertAvailable(
        connection, actor.tenantId, order.roomId, startAt, endAt, orderId
      );
      const oldHours = Math.ceil((order.endAt.getTime() - order.startAt.getTime()) / 3600000);
      const newHours = Math.ceil((endAt.getTime() - startAt.getTime()) / 3600000);
      const unitPrice = await this.resolveUnitPrice(connection, actor.tenantId, order, 'LOCKED');
      const amountDeltaCents = (newHours - oldHours) * unitPrice;
      await connection.execute(
        `UPDATE qipai_orders SET start_at = ?, end_at = ?,
           total_amount_cents = GREATEST(0, total_amount_cents + ?),
           adjustment_amount_cents = adjustment_amount_cents + ?
         WHERE tenant_id = ? AND id = ?`,
        [startAt, endAt, amountDeltaCents, amountDeltaCents, actor.tenantId, orderId]
      );
      await connection.execute(
        `UPDATE qipai_room_reservations SET starts_at = ?, ends_at = ?,
           expires_at = GREATEST(expires_at, ?)
         WHERE tenant_id = ? AND order_id = ?`,
        [startAt, endAt, endAt, actor.tenantId, orderId]
      );
      return this.record(connection, actor, order, 'ADJUST_TIME', input.reason, {
        startAt: order.startAt, endAt: order.endAt
      }, { startAt, endAt }, amountDeltaCents);
    });
  }

  async note(actor: OrderActor, orderId: string, note: string) {
    return this.transaction(async (connection) => {
      const order = await this.loadOrder(connection, actor.tenantId, orderId);
      this.assertManager(actor.access, order.storeId);
      const duplicate = await this.duplicate(connection, actor, orderId);
      if (duplicate) return this.duplicateResult(orderId, duplicate);
      await connection.execute(
        `UPDATE qipai_orders SET operator_note = ? WHERE tenant_id = ? AND id = ?`,
        [note.slice(0, 512), actor.tenantId, orderId]
      );
      return this.record(connection, actor, order, 'NOTE', note, {}, { note }, 0);
    });
  }

  async cancellationQuote(tenantId: string, userId: string, orderId: string) {
    return this.transaction(async (connection) => {
      const order = await this.loadOrder(connection, tenantId, orderId);
      await this.assertOwner(connection, tenantId, orderId, userId);
      const minutesBeforeStart = Math.floor((order.startAt.getTime() - Date.now()) / 60000);
      const feeCents = minutesBeforeStart >= order.cancellationCutoffMinutes
        ? 0 : Math.ceil(order.totalAmountCents * order.cancellationFeeBps / 10000);
      return {
        orderId,
        allowed: order.status !== 'IN_PROGRESS',
        cutoffMinutes: order.cancellationCutoffMinutes,
        feeCents,
        refundableCents: Math.max(0, order.totalAmountCents - feeCents)
      };
    });
  }

  private async record(
    connection: PoolConnection, actor: OrderActor, order: OrderRow,
    type: string, reason: string, before: object, after: object, amountDeltaCents: number
  ) {
    const [result] = await connection.execute<ResultSetHeader>(
      `INSERT INTO qipai_order_adjustments
        (tenant_id, order_id, adjustment_type, actor_id, source, trace_id,
         reason, before_values, after_values, amount_delta_cents)
       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
      [actor.tenantId, order.id, type, actor.userId, actor.source, actor.traceId,
        reason.slice(0, 512), JSON.stringify(before), JSON.stringify(after), amountDeltaCents]
    );
    await connection.execute(
      `INSERT INTO qipai_audit_logs
        (tenant_id, actor_type, actor_id, action, resource_type, resource_id,
         trace_id, ip, user_agent, metadata)
       VALUES (?, 'USER', ?, 'ORDER_MANUALLY_ADJUSTED', 'ORDER', ?, ?, ?, ?,
         JSON_OBJECT('adjustmentType', ?, 'amountDeltaCents', ?))`,
      [actor.tenantId, actor.userId, order.id, actor.traceId, actor.ip,
        actor.userAgent.slice(0, 255), type, amountDeltaCents]
    );
    return {
      orderId: order.id, adjustmentId: String(result.insertId),
      adjustmentType: type, amountDeltaCents, idempotent: false
    };
  }

  private async renewForActor(
    actor: OrderActor, orderId: string, input: {
      endAt: Date; pricingPolicy: PricingPolicy; reason: string;
    },
    authorize: (connection: PoolConnection, order: OrderRow) => Promise<void>
  ) {
    return this.transaction(async (connection) => {
      const order = await this.loadOrder(connection, actor.tenantId, orderId);
      await authorize(connection, order);
      const duplicate = await this.duplicate(connection, actor, orderId);
      if (duplicate) return this.duplicateResult(orderId, duplicate);
      if (!['PAID', 'RESERVED', 'IN_PROGRESS'].includes(order.status)) {
        throw new OrderManagementError('ORDER_RENEW_STATUS_INVALID');
      }
      if (input.endAt <= order.endAt) throw new OrderManagementError('ORDER_RENEW_END_INVALID');
      await this.lockRooms(connection, actor.tenantId, [order.roomId]);
      await this.assertAvailable(
        connection, actor.tenantId, order.roomId, order.endAt, input.endAt, orderId
      );
      const unitPrice = await this.resolveUnitPrice(
        connection, actor.tenantId, order, input.pricingPolicy
      );
      const amountDeltaCents = Math.ceil(
        (input.endAt.getTime() - order.endAt.getTime()) / 3600000
      ) * unitPrice;
      await connection.execute(
        `UPDATE qipai_orders
         SET end_at = ?, total_amount_cents = total_amount_cents + ?,
             adjustment_amount_cents = adjustment_amount_cents + ?
         WHERE tenant_id = ? AND id = ?`,
        [input.endAt, amountDeltaCents, amountDeltaCents, actor.tenantId, orderId]
      );
      await connection.execute(
        `UPDATE qipai_room_reservations
         SET ends_at = ?, expires_at = GREATEST(expires_at, ?)
         WHERE tenant_id = ? AND order_id = ?`,
        [input.endAt, input.endAt, actor.tenantId, orderId]
      );
      return this.record(connection, actor, order, 'RENEW', input.reason, {
        endAt: order.endAt
      }, { endAt: input.endAt, pricingPolicy: input.pricingPolicy }, amountDeltaCents);
    });
  }

  private async changeRoomForActor(
    actor: OrderActor, orderId: string, input: { roomId: string; reason: string },
    authorize: (
      connection: PoolConnection, order: OrderRow, target: RoomRow
    ) => Promise<void>
  ) {
    return this.transaction(async (connection) => {
      const order = await this.loadOrder(connection, actor.tenantId, orderId);
      const duplicate = await this.duplicate(connection, actor, orderId);
      if (duplicate) return this.duplicateResult(orderId, duplicate);
      if (!['PENDING_PAYMENT', 'PAID', 'RESERVED', 'IN_PROGRESS'].includes(order.status)) {
        throw new OrderManagementError('ORDER_ROOM_CHANGE_STATUS_INVALID');
      }
      if (input.roomId === order.roomId) throw new OrderManagementError('ORDER_ROOM_UNCHANGED');
      await this.lockRooms(connection, actor.tenantId, [order.roomId, input.roomId]);
      const target = await this.loadRoom(connection, actor.tenantId, input.roomId);
      await authorize(connection, order, target);
      await this.assertAvailable(
        connection, actor.tenantId, target.id, order.startAt, order.endAt, orderId
      );
      const oldRoom = await this.loadRoom(connection, actor.tenantId, order.roomId);
      const hours = Math.ceil((order.endAt.getTime() - order.startAt.getTime()) / 3600000);
      const amountDeltaCents = hours * (target.basePriceCents - oldRoom.basePriceCents);
      await connection.execute(
        `UPDATE qipai_orders
         SET store_id = ?, room_id = ?,
             total_amount_cents = GREATEST(0, total_amount_cents + ?),
             adjustment_amount_cents = adjustment_amount_cents + ?
         WHERE tenant_id = ? AND id = ?`,
        [target.storeId, target.id, amountDeltaCents, amountDeltaCents,
          actor.tenantId, orderId]
      );
      await connection.execute(
        `UPDATE qipai_room_reservations SET room_id = ?
         WHERE tenant_id = ? AND order_id = ?`,
        [target.id, actor.tenantId, orderId]
      );
      return this.record(connection, actor, order, 'CHANGE_ROOM', input.reason, {
        storeId: order.storeId, roomId: order.roomId
      }, { storeId: target.storeId, roomId: target.id }, amountDeltaCents);
    });
  }

  private async loadOrder(connection: PoolConnection, tenantId: string, orderId: string) {
    const [rows] = await connection.execute<OrderRow[]>(
      `SELECT o.id, o.store_id AS storeId, o.room_id AS roomId, o.status,
              o.start_at AS startAt, o.end_at AS endAt,
              o.total_amount_cents AS totalAmountCents,
              o.adjustment_amount_cents AS adjustmentAmountCents,
              s.cancellation_cutoff_minutes AS cancellationCutoffMinutes,
              s.cancellation_fee_bps AS cancellationFeeBps
       FROM qipai_orders o
       INNER JOIN qipai_stores s ON s.tenant_id = o.tenant_id AND s.id = o.store_id
       WHERE o.tenant_id = ? AND o.id = ? AND o.deleted_at IS NULL FOR UPDATE`,
      [tenantId, orderId]
    );
    if (!rows[0]) throw new OrderManagementError('ORDER_NOT_FOUND');
    return rows[0];
  }

  private async loadRoom(connection: PoolConnection, tenantId: string, roomId: string) {
    const [rows] = await connection.execute<RoomRow[]>(
      `SELECT r.id, r.store_id AS storeId, r.base_price_cents AS basePriceCents,
              r.weekday_price_cents AS weekdayPriceCents,
              r.holiday_price_cents AS holidayPriceCents,
              r.operational_status AS operationalStatus,
              r.configuration_status AS configurationStatus, s.timezone
       FROM qipai_rooms r
       INNER JOIN qipai_stores s
         ON s.tenant_id = r.tenant_id AND s.id = r.store_id AND s.deleted_at IS NULL
       WHERE r.tenant_id = ? AND r.id = ? AND r.deleted_at IS NULL`,
      [tenantId, roomId]
    );
    const room = rows[0];
    if (!room) throw new OrderManagementError('ROOM_NOT_FOUND');
    if (room.operationalStatus !== 'AVAILABLE' || room.configurationStatus !== 'ENABLED') {
      throw new OrderManagementError('ROOM_NOT_AVAILABLE');
    }
    return room;
  }

  private async lockRooms(connection: PoolConnection, tenantId: string, roomIds: string[]) {
    const sorted = [...new Set(roomIds)].sort((a, b) => Number(a) - Number(b));
    for (const roomId of sorted) {
      await connection.execute(
        `SELECT id FROM qipai_rooms WHERE tenant_id = ? AND id = ? FOR UPDATE`,
        [tenantId, roomId]
      );
    }
  }

  private async assertAvailable(
    connection: PoolConnection, tenantId: string, roomId: string,
    startAt: Date, endAt: Date, excludingOrderId: string
  ) {
    const [disabled] = await connection.execute<RowDataPacket[]>(
      `SELECT id FROM qipai_room_disabled_periods
       WHERE tenant_id = ? AND room_id = ? AND starts_at < ? AND ends_at > ? FOR UPDATE`,
      [tenantId, roomId, endAt, startAt]
    );
    if (disabled[0]) throw new OrderManagementError('ROOM_DISABLED_PERIOD');
    const [rows] = await connection.execute<RowDataPacket[]>(
      `SELECT id FROM qipai_room_reservations
       WHERE tenant_id = ? AND room_id = ? AND order_id <> ?
         AND status IN ('HELD', 'CONSUMED')
         AND (status = 'CONSUMED' OR expires_at > UTC_TIMESTAMP(3))
         AND starts_at < ? AND ends_at > ? FOR UPDATE`,
      [tenantId, roomId, excludingOrderId, endAt, startAt]
    );
    if (rows[0]) throw new OrderManagementError('TIME_SLOT_CONFLICT');
  }

  private async resolveUnitPrice(
    connection: PoolConnection, tenantId: string, order: OrderRow, policy: PricingPolicy
  ) {
    if (policy === 'LOCKED') {
      const [rows] = await connection.execute<SnapshotRow[]>(
        `SELECT unit_price_cents AS unitPriceCents
         FROM qipai_order_price_snapshots WHERE tenant_id = ? AND order_id = ?`,
        [tenantId, order.id]
      );
      if (!rows[0]) throw new OrderManagementError('ORDER_PRICE_SNAPSHOT_MISSING');
      return Number(rows[0].unitPriceCents);
    }
    const room = await this.loadRoom(connection, tenantId, order.roomId);
    const localDate = new Intl.DateTimeFormat('en-CA', {
      timeZone: room.timezone, year: 'numeric', month: '2-digit', day: '2-digit'
    }).format(order.endAt);
    const [holidayRows] = await connection.execute<RowDataPacket[]>(
      `SELECT 1 FROM qipai_holiday_calendar
       WHERE tenant_id = ? AND holiday_date = ? LIMIT 1`,
      [tenantId, localDate]
    );
    if (holidayRows[0] && room.holidayPriceCents > 0) return Number(room.holidayPriceCents);
    const weekdayName = new Intl.DateTimeFormat('en-US', {
      timeZone: room.timezone, weekday: 'short'
    }).format(order.endAt);
    if (['Mon', 'Tue', 'Wed', 'Thu', 'Fri'].includes(weekdayName)
      && room.weekdayPriceCents > 0) {
      return Number(room.weekdayPriceCents);
    }
    return Number(room.basePriceCents);
  }

  private async duplicate(connection: PoolConnection, actor: OrderActor, orderId: string) {
    const [rows] = await connection.execute<DuplicateRow[]>(
      `SELECT id, adjustment_type AS adjustmentType,
              amount_delta_cents AS amountDeltaCents
       FROM qipai_order_adjustments
       WHERE tenant_id = ? AND order_id = ? AND trace_id = ? LIMIT 1`,
      [actor.tenantId, orderId, actor.traceId]
    );
    return rows[0] ?? null;
  }

  private duplicateResult(orderId: string, duplicate: DuplicateRow) {
    return {
      orderId, adjustmentId: String(duplicate.id),
      adjustmentType: duplicate.adjustmentType,
      amountDeltaCents: Number(duplicate.amountDeltaCents), idempotent: true
    };
  }

  private assertManager(access: AccessProfile | undefined, storeId: string) {
    if (!access || !(access.capabilities.includes('tenant.manage')
      || access.roles.includes('PLATFORM_ADMIN')
      || (access.capabilities.includes('store.operation.write') && access.storeIds.includes(storeId)))) {
      throw new OrderManagementError('ORDER_MANAGEMENT_FORBIDDEN');
    }
  }

  private async assertOwner(
    connection: PoolConnection, tenantId: string, orderId: string, userId: string
  ) {
    const [rows] = await connection.execute<RowDataPacket[]>(
      `SELECT 1 FROM qipai_order_user_access
       WHERE tenant_id = ? AND order_id = ? AND user_id = ?`,
      [tenantId, orderId, userId]
    );
    if (!rows[0]) throw new OrderManagementError('ORDER_ACCESS_FORBIDDEN');
  }

  private async transaction<T>(work: (connection: PoolConnection) => Promise<T>) {
    const connection = await this.pool.getConnection();
    try {
      await connection.beginTransaction();
      const result = await work(connection);
      await connection.commit();
      return result;
    } catch (error) {
      await connection.rollback();
      throw error;
    } finally {
      connection.release();
    }
  }
}