/**
 * Central service error handler.
 * Default: service shows toast and swallows error; errorMode 'parent' rethrows for caller.
 * Returns ServiceResult<T> with ok/data or ok/error.
 */
import { AxiosError } from 'axios'

import { addToast } from '@/lib/toast'
import { texts } from '@/texts'
import { ensurePersianApiErrorMessage } from '@/services/apiErrorLocalization'
import { getServiceErrorCopy } from '@/helpers/serviceErrorCopy'

export const NETWORK_ERROR_MESSAGE_KEY = 'messages.networkError' as const

const isAxiosNetworkFailure = (error: AxiosError<ServiceErrorData>): boolean => {
  if (error.response) return false
  if (error.code === 'ERR_CANCELED') return false

  return true
}

export type ServiceErrorMode = 'service' | 'parent' | 'silent'

export interface ServiceCallOptions {
  /**
   * `'service'` (default): toast + return `{ ok: false }`.
   * `'silent'`: return `{ ok: false }` with no toast.
   * `'parent'`: **throw** the `ServiceError` (no `{ ok: false }`). Caller must
   * `try/catch` or use it inside a TanStack `queryFn`/`mutationFn`.
   */
  errorMode?: ServiceErrorMode
  /** Cancels the underlying HTTP request when the consumer becomes stale. */
  signal?: AbortSignal
}

export interface ServiceSuccessResult<T> {
  ok: true
  data: T
}

export interface ServiceErrorResult {
  ok: false
  error: ServiceError
}

export type ServiceResult<T> = ServiceSuccessResult<T> | ServiceErrorResult

interface ServiceErrorData {
  success?: boolean
  message?: string
  messageKey?: string
  code?: string
}

interface ServiceErrorResponse {
  data?: ServiceErrorData
  status?: number
}

export interface ServiceError extends Error {
  kind: 'validation' | 'network' | 'timeout' | 'auth' | 'permission' | 'server' | 'cancelled'
  messageKey?: string
  apiCode?: string
  /** Server body.message (array or string) for direct toast display */
  detailMessage?: string
  statusCode?: number
  response?: ServiceErrorResponse
}

/** Supports { body: { message: string[] } } and common variants */
export const extractServerErrorDetail = (data: unknown, status?: number): string | null => {
  if (data === null || data === undefined || typeof data !== 'object') return null

  const d = data as Record<string, unknown>

  const code = typeof d.code === 'string' ? d.code : undefined

  const pickMessage = (m: unknown): string | null => {
    if (Array.isArray(m)) {
      const parts = m
        .filter((x): x is string => typeof x === 'string' && x.trim().length > 0)
        .map((item) => ensurePersianApiErrorMessage(item, status, code))

      return parts.length ? [...new Set(parts)].join('\n') : null
    }

    if (typeof m === 'string' && m.trim()) return ensurePersianApiErrorMessage(m, status, code)

    return null
  }

  const body = d.body

  if (body && typeof body === 'object') {
    const fromBody = pickMessage((body as Record<string, unknown>).message)

    if (fromBody) return fromBody
  }

  return pickMessage(d.message)
}

const isGenericHttpClientMessage = (message: string): boolean =>
  /^Request failed with status code \d+$/i.test(message) || /^Network Error$/i.test(message)

/** Toast/error text — server detailMessage / message first */
export const resolveServiceErrorDisplayMessage = (
  error: Pick<ServiceError, 'detailMessage' | 'message' | 'messageKey'>,
  copy: { apiError: string; networkError: string }
): string => {
  if (error.messageKey === NETWORK_ERROR_MESSAGE_KEY) {
    return copy.networkError
  }

  const detail = error.detailMessage?.trim()

  if (detail) return ensurePersianApiErrorMessage(detail)

  const message = error.message?.trim()

  if (message && !isGenericHttpClientMessage(message)) {
    return ensurePersianApiErrorMessage(message)
  }

  return copy.apiError
}

export const createServiceError = (message: string, messageKey?: string): ServiceError => {
  const localizedMessage = ensurePersianApiErrorMessage(message)
  const error = new Error(localizedMessage) as ServiceError

  error.kind = 'server'

  if (messageKey) {
    error.messageKey = messageKey
  }

  error.response = {
    data: {
      success: false,
      message: localizedMessage,
      messageKey,
    },
  }

  return error
}

const isAxiosLikeError = (error: unknown): error is AxiosError<ServiceErrorData> => {
  return error instanceof AxiosError || (typeof error === 'object' && error !== null && 'isAxiosError' in error)
}

export const normalizeServiceError = (error: unknown, fallbackMessageKey = 'messages.mockServerError'): ServiceError => {
  const { apiError: defaultApiError, networkError: localizedNetworkError } = getServiceErrorCopy()

  if (isAxiosLikeError(error)) {
    if (error.code === 'ERR_CANCELED') {
      const cancelledError = new Error(texts.common.requestCancelled) as ServiceError

      cancelledError.kind = 'cancelled'

      return cancelledError
    }

    if (isAxiosNetworkFailure(error)) {
      const normalizedNetwork = new Error(localizedNetworkError) as ServiceError

      normalizedNetwork.kind = error.code === 'ECONNABORTED' ? 'timeout' : 'network'
      normalizedNetwork.messageKey = NETWORK_ERROR_MESSAGE_KEY
      normalizedNetwork.response = {
        data: {
          message: localizedNetworkError,
          messageKey: NETWORK_ERROR_MESSAGE_KEY,
        },
      }

      return normalizedNetwork
    }

    const payload = error.response?.data
    const detailMessage = extractServerErrorDetail(payload, error.response?.status)
    const rawMessage = payload && typeof payload === 'object' ? (payload as Record<string, unknown>).message : undefined
    const legacyString = typeof rawMessage === 'string' ? rawMessage : typeof error.message === 'string' ? error.message : undefined
    const status = error.response?.status
    const payloadMessageKey = payload && typeof payload === 'object' ? (payload as Record<string, unknown>).messageKey : undefined
    const payloadCode = payload && typeof payload === 'object' ? (payload as Record<string, unknown>).code : undefined
    const axiosMessage =
      detailMessage || ensurePersianApiErrorMessage(legacyString, status, typeof payloadCode === 'string' ? payloadCode : undefined)
    const axiosMessageKey: string = typeof payloadMessageKey === 'string' ? payloadMessageKey || fallbackMessageKey : fallbackMessageKey
    const normalizedError = new Error(axiosMessage) as ServiceError

    normalizedError.kind =
      status === 401 ? 'auth' : status === 403 ? 'permission' : status === 400 || status === 422 ? 'validation' : 'server'

    if (detailMessage) {
      normalizedError.detailMessage = detailMessage
    }

    if (typeof payloadCode === 'string') {
      normalizedError.apiCode = payloadCode
    }

    normalizedError.messageKey = detailMessage ? undefined : axiosMessageKey
    normalizedError.statusCode = error.response?.status
    normalizedError.response = {
      ...error.response,
      data: {
        ...(payload && typeof payload === 'object' ? payload : {}),
        message: axiosMessage,
        messageKey: normalizedError.messageKey,
      },
    }

    return normalizedError
  }

  if (error instanceof Error) {
    const maybeServiceError = error as ServiceError
    const localizedMessage = ensurePersianApiErrorMessage(
      maybeServiceError.message,
      maybeServiceError.statusCode,
      maybeServiceError.apiCode
    )

    maybeServiceError.message = localizedMessage

    maybeServiceError.kind ||= 'server'
    maybeServiceError.messageKey = maybeServiceError.messageKey || fallbackMessageKey
    maybeServiceError.response ??= {
      data: {
        message: localizedMessage,
        messageKey: maybeServiceError.messageKey,
      },
    }

    return maybeServiceError
  }

  return createServiceError(defaultApiError, fallbackMessageKey)
}

/** True when the service must throw instead of returning `{ ok: false }`. */
export const shouldBubbleErrorToParent = (options?: ServiceCallOptions): boolean => {
  return options?.errorMode === 'parent'
}

export const handleServiceError = (error: unknown, options?: ServiceCallOptions): ServiceError => {
  const normalizedError = normalizeServiceError(error)
  const { apiError, networkError } = getServiceErrorCopy()

  if (normalizedError.kind !== 'cancelled' && options?.errorMode !== 'silent' && !shouldBubbleErrorToParent(options)) {
    addToast({
      title: resolveServiceErrorDisplayMessage(normalizedError, { apiError, networkError }),
      color: 'danger',
    })
  }

  return normalizedError
}

export const successResult = <T>(data: T): ServiceResult<T> => ({
  ok: true,
  data,
})

export const errorResult = (error: ServiceError): ServiceResult<never> => ({
  ok: false,
  error,
})