import { adminApiClient } from './client'
import type { EditCardPackDto, CardPackPreviewDto, PaginatedResponse } from '@/types/models'
import type { AxiosError } from 'axios'

export interface PacksApiError {
  message: string
  statusCode?: number
  field?: string
  originalError?: unknown
  name: 'PacksApiError'
}

export function createPacksApiError(
  message: string,
  statusCode?: number,
  field?: string,
  originalError?: unknown
): PacksApiError {
  return {
    message,
    statusCode,
    field,
    originalError,
    name: 'PacksApiError',
  }
}

export function isPacksApiError(error: unknown): error is PacksApiError {
  return (
    typeof error === 'object' &&
    error !== null &&
    'name' in error &&
    error.name === 'PacksApiError'
  )
}

export const packsApi = {
  // Get all packs with pagination and search
  getPacks: async (params?: {
    page?: number
    limit?: number
    search?: string
    showDisabled?: boolean
  }): Promise<PaginatedResponse<CardPackPreviewDto>> => {
    try {
      const response = await adminApiClient.get('/api/admin/packs', {
        params: {
          page: params?.page || 1,
          limit: params?.limit || 20,
          search: params?.search,
          isPublic: params?.showDisabled === false ? true : undefined,
        },
      })
      // Transform backend response to match frontend PaginatedResponse
      const backendData = response.data
      return {
        items: backendData.packs.map((pack: any) => ({
          id: pack.id,
          title: pack.name,
          cards: pack.questionCount,
          enabled: pack.isPublic,
        })),
        total: backendData.total,
        page: backendData.page,
        limit: backendData.limit,
        totalPages: backendData.totalPages,
      }
    } catch (error) {
      const axiosError = error as AxiosError<{ error?: string; message?: string; field?: string }>
      
      // Check for validation errors (limit too high, etc.)
      if (axiosError.response?.status === 400) {
        const errorData = axiosError.response.data
        if (errorData?.message?.includes('Limit')) {
          throw createPacksApiError(
            `Invalid limit: ${errorData.message}. Maximum allowed limit is 100.`,
            axiosError.response.status,
            'limit',
            error
          )
        }
      }
      
      throw createPacksApiError(
        axiosError.response?.data?.message || 
        axiosError.response?.data?.error || 
        'Failed to load packs',
        axiosError.response?.status,
        axiosError.response?.data?.field,
        error
      )
    }
  },

  // Get pack details by ID for editing
  getPack: async (packId: string): Promise<EditCardPackDto> => {
    try {
      const response = await adminApiClient.get(`/api/admin/packs/${packId}`)
      const pack = response.data
      // Transform backend response to match EditCardPackDto
      return {
        id: pack.id,
        name: pack.name,
        description: pack.description,
        category: pack.category,
        isPublic: pack.isPublic,
        questions: pack.questions,
      }
    } catch (error) {
      const axiosError = error as AxiosError<{ error?: string; message?: string }>
      
      if (axiosError.response?.status === 404) {
        throw createPacksApiError(
          `Pack not found: The pack with ID "${packId}" does not exist or has been deleted.`,
          axiosError.response.status,
          undefined,
          error
        )
      }
      
      throw createPacksApiError(
        axiosError.response?.data?.message || 
        axiosError.response?.data?.error || 
        `Failed to load pack ${packId}`,
        axiosError.response?.status,
        undefined,
        error
      )
    }
  },

  // Create or update pack
  upsertPack: async (pack: EditCardPackDto): Promise<{ success: boolean; pack: EditCardPackDto }> => {
    try {
      const isUpdate = pack.id && pack.id.length > 0
      const url = isUpdate ? `/api/admin/packs/${pack.id}` : '/api/admin/packs'
      const method = isUpdate ? 'patch' : 'post'

      const response = await adminApiClient[method](url, {
        name: pack.name,
        description: pack.description,
        category: pack.category,
        isPublic: pack.isPublic,
        questions: pack.questions,
      })

      return {
        success: true,
        pack: response.data,
      }
    } catch (error) {
      const axiosError = error as AxiosError<{ error?: string; message?: string; field?: string; details?: string }>
      const isUpdate = pack.id && pack.id.length > 0
      const operation = isUpdate ? 'update pack' : 'create pack'
      const baseMessage = axiosError.response?.data?.message || 
        axiosError.response?.data?.error || 
        `Failed to ${operation}`
      
      let fullMessage = baseMessage
      if (axiosError.response?.data?.details) {
        fullMessage += `. ${axiosError.response.data.details}`
      }
      
      // Special handling for common errors
      if (axiosError.response?.status === 404 && isUpdate) {
        fullMessage = `Pack not found: The pack you're trying to update (ID: ${pack.id}) does not exist.`
      }
      
      if (axiosError.response?.data?.field) {
        fullMessage += ` (Field: ${axiosError.response.data.field})`
      }
      
      throw createPacksApiError(
        fullMessage,
        axiosError.response?.status,
        axiosError.response?.data?.field,
        error
      )
    }
  },

  // Delete pack
  deletePack: async (packId: string): Promise<{ success: boolean; message: string }> => {
    try {
      const response = await adminApiClient.delete(`/api/admin/packs/${packId}`)
      return response.data
    } catch (error) {
      const axiosError = error as AxiosError<{ error?: string; message?: string }>

      if (axiosError.response?.status === 404) {
        throw createPacksApiError(
          `Pack not found: The pack with ID "${packId}" does not exist and cannot be deleted.`,
          axiosError.response.status,
          undefined,
          error
        )
      }

      throw createPacksApiError(
        axiosError.response?.data?.message ||
        axiosError.response?.data?.error ||
        `Failed to delete pack ${packId}`,
        axiosError.response?.status,
        undefined,
        error
      )
    }
  },

  // Get empty template for import
  getTemplate: async (): Promise<{
    templateVersion: string
    instructions: string
    questions: Array<{ question: string; answers: Array<{ text: string; points: number }> }>
  }> => {
    try {
      const response = await adminApiClient.get('/api/admin/packs/export/template')
      return response.data
    } catch (error) {
      const axiosError = error as AxiosError<{ error?: string; message?: string }>
      throw createPacksApiError(
        axiosError.response?.data?.message ||
        axiosError.response?.data?.error ||
        'Failed to get template',
        axiosError.response?.status,
        undefined,
        error
      )
    }
  },

  // Export pack to JSON
  exportPack: async (packId: string): Promise<{
    templateVersion: string
    exportedAt: string
    packInfo: {
      name: string
      description: string
      category: string
      isPublic: boolean
    }
    questions: Array<{ question: string; answers: Array<{ text: string; points: number }> }>
  }> => {
    try {
      const response = await adminApiClient.get(`/api/admin/packs/${packId}/export`)
      return response.data
    } catch (error) {
      const axiosError = error as AxiosError<{ error?: string; message?: string }>

      if (axiosError.response?.status === 404) {
        throw createPacksApiError(
          `Pack not found: The pack with ID "${packId}" does not exist.`,
          axiosError.response.status,
          undefined,
          error
        )
      }

      throw createPacksApiError(
        axiosError.response?.data?.message ||
        axiosError.response?.data?.error ||
        `Failed to export pack ${packId}`,
        axiosError.response?.status,
        undefined,
        error
      )
    }
  },

  // Import pack from JSON
  importPack: async (data: {
    name: string
    description: string
    category: string
    isPublic: boolean
    questions: Array<{ question: string; answers: Array<{ text: string; points: number }> }>
  }): Promise<EditCardPackDto> => {
    try {
      const response = await adminApiClient.post('/api/admin/packs/import', data)
      return response.data
    } catch (error) {
      const axiosError = error as AxiosError<{ error?: string; message?: string }>
      throw createPacksApiError(
        axiosError.response?.data?.message ||
        axiosError.response?.data?.error ||
        'Failed to import pack',
        axiosError.response?.status,
        undefined,
        error
      )
    }
  },
}