/**
 * 通用 CRUD 服务基类
 * Generic CRUD Service Base Class
 *
 * 提供标准的 CRUD 操作，支持分页、搜索、排序等功能
 * Provides standard CRUD operations with pagination, search, and sorting
 */

import { PrismaClient } from '@prisma/client'
import type { BaseEntity, PaginatedResponse, CrudOptions } from '@nuxt4crud/shared'

/**
 * CRUD 服务基类
 * CRUD Service Base Class
 */
export abstract class BaseCrudService<
  T extends BaseEntity,
  CreateInput,
  UpdateInput,
  QueryParams = any,
> {
  protected model: any
  protected options: CrudOptions

  constructor(
    protected prisma: PrismaClient,
    protected modelName: string,
    options: Partial<CrudOptions> = {}
  ) {
    this.model = (prisma as any)[modelName]
    this.options = {
      softDelete: false,
      defaultOrderBy: 'createdAt',
      defaultOrderDirection: 'desc',
      searchableFields: [],
      uniqueFields: [],
      ...options,
    }
  }

  /**
   * 获取列表（支持分页、搜索、排序）
   * Get list with pagination, search, and sorting
   */
  async findMany(
    params: QueryParams & {
      page?: number
      limit?: number
      search?: string
      orderBy?: string
      orderDirection?: 'asc' | 'desc'
    }
  ): Promise<PaginatedResponse<T>> {
    const {
      page = 1,
      limit = 10,
      search = '',
      orderBy = this.options.defaultOrderBy,
      orderDirection = this.options.defaultOrderDirection,
      ...filters
    } = params

    const where = this.buildWhereClause(search, filters)

    const skip = (page - 1) * limit
    const take = limit

    const [data, total] = await Promise.all([
      this.model.findMany({
        where,
        skip,
        take,
        orderBy: { [orderBy]: orderDirection },
      }),
      this.model.count({ where }),
    ])

    return {
      data,
      total,
      page,
      limit,
      totalPages: Math.ceil(total / limit),
    }
  }

  /**
   * 根据ID查找
   * Find by ID
   */
  async findById(id: number): Promise<T | null> {
    return await this.model.findUnique({
      where: { id },
    })
  }

  /**
   * 根据多个ID查找记录
   * Find records by multiple IDs
   *
   * @param ids 要查询的ID数组
   * @returns 匹配的记录列表
   */
  async findByIds(ids: number[]): Promise<T[]> {
    const normalizedIds = Array.from(
      new Set(
        (ids || [])
          .map(id => Number(id))
          .filter(id => Number.isFinite(id) && id > 0)
      )
    )

    if (normalizedIds.length === 0) {
      return []
    }

    return await this.model.findMany({
      where: { id: { in: normalizedIds } },
    })
  }

  /**
   * 创建记录
   * Create record
   */
  async create(data: CreateInput): Promise<T> {
    await this.validateCreate(data)

    const transformedData = await this.transformCreateData(data)

    return await this.model.create({
      data: transformedData,
    })
  }

  /**
   * 更新记录
   * Update record
   */
  async update(id: number, data: UpdateInput): Promise<T> {
    const existing = await this.findById(id)
    if (!existing) {
      const error = new Error('记录不存在')
      ;(error as any).statusCode = 404
      throw error
    }

    await this.validateUpdate(id, data, existing)

    const transformedData = await this.transformUpdateData(data, existing)

    return await this.model.update({
      where: { id },
      data: transformedData,
    })
  }

  /**
   * 删除记录
   * Delete record
   */
  async delete(id: number): Promise<void> {
    const existing = await this.findById(id)
    if (!existing) {
      const error = new Error('记录不存在')
      ;(error as any).statusCode = 404
      throw error
    }

    await this.validateDelete(id, existing)

    if (this.options.softDelete) {
      await this.model.update({
        where: { id },
        data: { deletedAt: new Date() },
      })
    } else {
      await this.model.delete({
        where: { id },
      })
    }
  }

  /**
   * 构建查询条件
   * Build where clause
   */
  protected buildWhereClause(search: string, filters: any): any {
    const where: any = {}

    // 搜索功能
    if (search && this.options.searchableFields?.length) {
      where.OR = this.options.searchableFields.map(field => ({
        [field]: { contains: search },
      }))
    }

    // 过滤条件
    Object.entries(filters).forEach(([key, value]) => {
      if (value !== undefined && value !== null && key !== 'search') {
        where[key] = value
      }
    })

    // 软删除过滤
    if (this.options.softDelete) {
      where.deletedAt = null
    }

    return where
  }

  /**
   * 创建前验证钩子
   * Pre-create validation hook
   */
  protected async validateCreate(data: CreateInput): Promise<void> {
    // 子类可以重写此方法
  }

  /**
   * 更新前验证钩子
   * Pre-update validation hook
   */
  protected async validateUpdate(id: number, data: UpdateInput, existing: T): Promise<void> {
    // 子类可以重写此方法
  }

  /**
   * 删除前验证钩子
   * Pre-delete validation hook
   */
  protected async validateDelete(id: number, existing: T): Promise<void> {
    // 子类可以重写此方法
  }

  /**
   * 创建数据转换钩子
   * Create data transformation hook
   */
  protected async transformCreateData(data: CreateInput): Promise<any> {
    return data
  }

  /**
   * 更新数据转换钩子
   * Update data transformation hook
   */
  protected async transformUpdateData(data: UpdateInput, existing: T): Promise<any> {
    return data
  }
}