import type { PoolConnection, RowDataPacket } from "mysql2/promise";
import { pool } from "../../db/pool";

type DbExecutor = typeof pool | PoolConnection;

export interface RolePermissionRecord {
  roleId: number;
  roleCode: string;
  roleName: string;
  roleDescription: string | null;
  isSystem: boolean;
  permissions: string[];
}

interface RolePermissionRow extends RowDataPacket {
  role_id: number;
  role_code: string;
  role_name: string;
  role_description: string | null;
  is_system: number;
  permission_code: string | null;
}

interface PermissionCodeRow extends RowDataPacket {
  permission_code: string;
}

function toRolePermissionRecords(
  rows: RolePermissionRow[],
): RolePermissionRecord[] {
  const records = new Map<number, RolePermissionRecord>();

  for (const row of rows) {
    const record = records.get(row.role_id) ?? {
      roleId: row.role_id,
      roleCode: row.role_code,
      roleName: row.role_name,
      roleDescription: row.role_description,
      isSystem: row.is_system === 1,
      permissions: [],
    };

    if (row.permission_code) {
      record.permissions.push(row.permission_code);
    }

    records.set(row.role_id, record);
  }

  return [...records.values()];
}

export const permissionRepository = {
  async withTransaction<T>(
    handler: (connection: PoolConnection) => Promise<T>,
  ): Promise<T> {
    const connection = await pool.getConnection();

    try {
      await connection.beginTransaction();
      const result = await handler(connection);
      await connection.commit();
      return result;
    } catch (error) {
      await connection.rollback();
      throw error;
    } finally {
      connection.release();
    }
  },

  async listRolePermissions(
    db: DbExecutor = pool,
  ): Promise<RolePermissionRecord[]> {
    const [rows] = await db.execute<RolePermissionRow[]>(
      `
        SELECT
          r.id AS role_id,
          r.code AS role_code,
          r.name AS role_name,
          r.description AS role_description,
          r.is_system,
          rp.permission_code
        FROM roles r
        LEFT JOIN role_permissions rp
          ON rp.role_id = r.id AND rp.deleted_at IS NULL
        WHERE r.deleted_at IS NULL
        ORDER BY r.id ASC, rp.permission_code ASC
      `,
    );

    return toRolePermissionRecords(rows);
  },

  async findRolePermissionsByRoleId(
    roleId: number,
    db: DbExecutor = pool,
  ): Promise<RolePermissionRecord | null> {
    const [rows] = await db.execute<RolePermissionRow[]>(
      `
        SELECT
          r.id AS role_id,
          r.code AS role_code,
          r.name AS role_name,
          r.description AS role_description,
          r.is_system,
          rp.permission_code
        FROM roles r
        LEFT JOIN role_permissions rp
          ON rp.role_id = r.id AND rp.deleted_at IS NULL
        WHERE r.id = ?
          AND r.deleted_at IS NULL
        ORDER BY rp.permission_code ASC
      `,
      [roleId],
    );

    return toRolePermissionRecords(rows)[0] ?? null;
  },

  async findPermissionCodesByRoleCodes(roleCodes: string[]): Promise<string[]> {
    if (roleCodes.length === 0) {
      return [];
    }

    const placeholders = roleCodes.map(() => "?").join(", ");
    const [rows] = await pool.execute<PermissionCodeRow[]>(
      `
        SELECT DISTINCT rp.permission_code
        FROM role_permissions rp
        INNER JOIN roles r ON r.id = rp.role_id
        WHERE r.code IN (${placeholders})
          AND r.deleted_at IS NULL
          AND rp.deleted_at IS NULL
        ORDER BY rp.permission_code ASC
      `,
      roleCodes,
    );

    return rows.map((row) => row.permission_code);
  },

  async replaceRolePermissions(
    roleId: number,
    permissionCodes: string[],
    db: DbExecutor = pool,
  ): Promise<void> {
    await db.execute(
      `
        UPDATE role_permissions
        SET deleted_at = CURRENT_TIMESTAMP(3)
        WHERE role_id = ? AND deleted_at IS NULL
      `,
      [roleId],
    );

    if (permissionCodes.length === 0) {
      return;
    }

    await db.execute(
      `
        INSERT INTO role_permissions (role_id, permission_code)
        VALUES ${permissionCodes.map(() => "(?, ?)").join(", ")}
        ON DUPLICATE KEY UPDATE
          deleted_at = NULL,
          created_at = CURRENT_TIMESTAMP(3)
      `,
      permissionCodes.flatMap((permissionCode) => [roleId, permissionCode]),
    );
  },
};