import { createHash } from 'node:crypto'
import { appendFileSync, mkdirSync } from 'node:fs'
import { dirname, join } from 'node:path'

import { ApiClientError, createApiClient, type ApiClient } from '@geo/http-client'
import type {
  ApiEnvelope,
  ApiErrorEnvelope,
  CancelDesktopTaskRequest,
  CompleteDesktopTaskRequest,
  CreatePublishJobResponse,
  DesktopAccountInfo,
  DesktopArticleContent,
  DesktopClientHeartbeatRequest,
  DesktopClientHeartbeatResponse,
  DesktopClientReleaseCheckResponse,
  DesktopClientRotateResponse,
  DesktopPublishTaskListResponse,
  DesktopRuntimeSessionSyncRequest,
  DesktopTaskInfo,
  ExtendDesktopTaskRequest,
  LeaseDesktopTaskRequest,
  LeaseDesktopTaskResponse,
  ListDesktopPublishTasksParams,
  MonitoringLeaseTasksPayload,
  MonitoringLeaseTasksResponse,
  MonitoringResumeTasksPayload,
  MonitoringResumeTasksResponse,
  MonitoringSkipTaskPayload,
  MonitoringSkipTaskResponse,
  MonitoringTaskResultPayload,
  MonitoringTaskResultResponse,
  ReportDesktopAccountHealthRequest,
  ReportDesktopAccountHealthResponse,
  UpsertDesktopAccountRequest,
} from '@geo/shared-types'
import { app } from 'electron/main'

import { normalizeDesktopApiBaseURL } from '../../shared/api-base-url'
import {
  failObservedRequest,
  resolveObservedRequest,
  startObservedRequest,
} from '../network-observer'
import { canUseRendererDevtoolsProxy, rendererDevtoolsFetch } from '../renderer-devtools-proxy'

type TransportAuthState = 'pending' | 'registered' | 'expired'
type TransportDispatchState = 'idle' | 'connecting' | 'streaming'

type ObservedAxiosConfig = {
  method?: string
  url?: string
  baseURL?: string
  headers?: Record<string, unknown>
  __observedRequestId?: string
}

interface DesktopTransportSession {
  baseURL: string
  clientToken: string | null
}

interface MonitoringCancelTaskPayload {
  lease_token: string
  reason?: string | null
}

interface MonitoringCancelTaskResponse {
  task_id: number
  task_status: string
}

let desktopApiClient: ApiClient | null = null
let transportSession: DesktopTransportSession = {
  baseURL: normalizeDesktopApiBaseURL(process.env.DESKTOP_API_BASE_URL),
  clientToken: null,
}
const ACCOUNT_UPSERT_CACHE_TTL_MS = 5 * 60_000
const ACCOUNT_UPSERT_DIAGNOSTIC_FILE = 'desktop-account-upsert-errors.jsonl'

interface AccountUpsertCacheEntry {
  signature: string
  expiresAt: number
  response: DesktopAccountInfo
  inFlight: Promise<DesktopAccountInfo> | null
}

const accountUpsertCache = new Map<string, AccountUpsertCacheEntry>()

const transportState = {
  baseURL: transportSession.baseURL,
  initializedAt: 0,
  mode: 'rabbitmq-first' as const,
  requestDebugMode: 'main-process' as 'main-process' | 'renderer-devtools',
  auth: 'pending' as TransportAuthState,
  dispatchState: 'idle' as TransportDispatchState,
  lastHeartbeatAt: 0,
  lastHeartbeatStatus: 'idle' as 'idle' | 'success' | 'failed',
  lastPullAt: 0,
  lastPullStatus: 'idle' as 'idle' | 'success' | 'failed',
}

function createDesktopClient(baseURL: string): ApiClient {
  const client = createApiClient({
    baseURL,
    timeoutMs: 15000,
  })

  client.raw.interceptors.request.use((config) => {
    if (transportSession.clientToken) {
      config.headers = config.headers ?? {}
      ;(config.headers as Record<string, string>).Authorization =
        `Bearer ${transportSession.clientToken}`
    }

    const observedConfig = config as ObservedAxiosConfig
    observedConfig.__observedRequestId = startObservedRequest({
      source: 'transport',
      label: 'desktop.api',
      method: config.method,
      url: resolveObservedRequestURL(config.url, config.baseURL ?? baseURL),
    })
    return config
  })

  client.raw.interceptors.response.use(
    (response) => {
      const observedConfig = response.config as ObservedAxiosConfig
      if (observedConfig.__observedRequestId) {
        resolveObservedRequest(observedConfig.__observedRequestId, {
          phase: 'response',
          status: response.status,
        })
      }
      return response
    },
    (error: unknown) => {
      const responseError = error as {
        config?: ObservedAxiosConfig
        response?: { status?: number }
      }
      const requestId = responseError.config?.__observedRequestId
      if (requestId) {
        if (typeof responseError.response?.status === 'number') {
          resolveObservedRequest(requestId, {
            phase: 'response',
            status: responseError.response.status,
          })
        } else {
          failObservedRequest(requestId, error)
        }
      }
      return Promise.reject(error)
    },
  )

  return client
}

function stableJson(value: unknown): string {
  if (Array.isArray(value)) {
    return `[${value.map((item) => stableJson(item)).join(',')}]`
  }
  if (value && typeof value === 'object') {
    return `{${Object.entries(value as Record<string, unknown>)
      .sort(([left], [right]) => left.localeCompare(right))
      .map(([key, item]) => `${JSON.stringify(key)}:${stableJson(item)}`)
      .join(',')}}`
  }
  return JSON.stringify(value)
}

function accountUpsertCacheKey(payload: UpsertDesktopAccountRequest): string {
  return [payload.platform.trim(), payload.platform_uid.trim()].join('::')
}

function accountUpsertSignature(payload: UpsertDesktopAccountRequest): string {
  return stableJson({
    platform: payload.platform.trim(),
    platform_uid: payload.platform_uid.trim(),
    account_fingerprint: payload.account_fingerprint ?? null,
    display_name: payload.display_name.trim(),
    avatar_url: payload.avatar_url ?? null,
    health: payload.health,
    verified_at: payload.verified_at ?? null,
    tags: payload.tags ?? [],
    if_sync_version: payload.if_sync_version ?? null,
  })
}

function clearAccountUpsertCache(): void {
  accountUpsertCache.clear()
}

function diagnosticHash(value: string | null | undefined): string | null {
  const normalized = value?.trim()
  if (!normalized) {
    return null
  }
  return createHash('sha256').update(normalized).digest('hex').slice(0, 16)
}

function normalizeErrorForDiagnostics(error: unknown): Record<string, unknown> {
  if (error instanceof ApiClientError) {
    return {
      name: error.name,
      message: error.message,
      code: error.code,
      status: error.status ?? null,
      detail: error.detail ?? null,
      requestId: error.requestId ?? null,
      handled: error.handled === true,
    }
  }

  if (error instanceof Error) {
    return {
      name: error.name,
      message: error.message,
    }
  }

  return {
    name: typeof error,
    message: String(error),
  }
}

function appendAccountUpsertDiagnostic(payload: UpsertDesktopAccountRequest, error: unknown): void {
  const target = join(app.getPath('userData'), ACCOUNT_UPSERT_DIAGNOSTIC_FILE)
  const event = {
    at: new Date().toISOString(),
    action: 'desktop_account_upsert_failed',
    transport: {
      baseURL: transportState.baseURL,
      auth: transportState.auth,
      requestDebugMode: transportState.requestDebugMode,
      hasClient: desktopApiClient !== null,
      hasClientToken: Boolean(transportSession.clientToken),
    },
    request: {
      platform: payload.platform,
      platformUidHash: diagnosticHash(payload.platform_uid),
      accountFingerprintHash: diagnosticHash(payload.account_fingerprint ?? null),
      displayName: payload.display_name,
      health: payload.health,
      verifiedAt: payload.verified_at ?? null,
      tagCount: payload.tags?.length ?? 0,
      hasIfSyncVersion: typeof payload.if_sync_version === 'number',
    },
    error: normalizeErrorForDiagnostics(error),
  }

  try {
    mkdirSync(dirname(target), { recursive: true })
    appendFileSync(target, `${JSON.stringify(event)}\n`, 'utf8')
  } catch {
    // Best-effort diagnostics. Never block account binding on local log writes.
  }
}

function currentRequestDebugMode(): 'main-process' | 'renderer-devtools' {
  return canUseRendererDevtoolsProxy() ? 'renderer-devtools' : 'main-process'
}

function resolveDesktopURL(path: string): string {
  return new URL(path, transportSession.baseURL).toString()
}

export function resolveDesktopApiURL(path: string): string {
  return resolveDesktopURL(path)
}

export async function fetchDesktopApiURL(
  input: string | URL,
  init: RequestInit = {},
): Promise<Response> {
  const headers = new Headers(init.headers)
  if (transportSession.clientToken && !headers.has('Authorization')) {
    headers.set('Authorization', `Bearer ${transportSession.clientToken}`)
  }

  const url =
    input instanceof URL
      ? input.toString()
      : /^https?:\/\//i.test(input)
        ? input
        : resolveDesktopURL(input)
  return fetch(url, {
    ...init,
    headers,
  })
}

function resolveObservedRequestURL(path: string | undefined, baseURL: string): string {
  if (!path) {
    return baseURL
  }

  try {
    return new URL(path, baseURL).toString()
  } catch {
    return path
  }
}

function shouldFallbackToMainProcess(error: unknown): boolean {
  if (error instanceof ApiClientError) {
    if (typeof error.status === 'number' && error.status > 0) {
      return false
    }
    return /Failed to fetch|renderer_devtools_proxy_/i.test(error.message)
  }

  if (error instanceof Error) {
    return /Failed to fetch|renderer_devtools_proxy_/i.test(error.message)
  }

  return false
}

async function proxyDesktopRequest<T, B = unknown>(
  method: 'GET' | 'POST' | 'DELETE',
  path: string,
  body?: B,
): Promise<T> {
  const headers: Record<string, string> = {
    Accept: 'application/json',
  }

  let serializedBody: string | undefined
  if (body !== undefined) {
    headers['Content-Type'] = 'application/json'
    serializedBody = JSON.stringify(body)
  }
  if (transportSession.clientToken) {
    headers.Authorization = `Bearer ${transportSession.clientToken}`
  }

  const response = await rendererDevtoolsFetch({
    url: resolveDesktopURL(path),
    method,
    headers,
    body: serializedBody,
  })

  if (response.error) {
    throw new ApiClientError({ message: response.error })
  }

  let payload: ApiEnvelope<T> | Partial<ApiErrorEnvelope> | null = null
  if (response.bodyText) {
    try {
      payload = JSON.parse(response.bodyText) as ApiEnvelope<T> | Partial<ApiErrorEnvelope>
    } catch {
      payload = null
    }
  }

  if (!response.ok) {
    const errorPayload = payload as Partial<ApiErrorEnvelope> | null
    throw new ApiClientError({
      message: errorPayload?.message ?? `desktop_http_${response.status}`,
      code: errorPayload?.code ?? 50000,
      status: response.status,
      detail: errorPayload?.detail,
      requestId: errorPayload?.request_id,
    })
  }

  if (!payload || typeof payload !== 'object' || !('data' in payload)) {
    throw new ApiClientError({
      message: 'desktop_invalid_api_envelope',
      status: response.status,
    })
  }

  return payload.data as T
}

async function desktopGet<T>(path: string): Promise<T> {
  transportState.requestDebugMode = currentRequestDebugMode()
  if (transportState.requestDebugMode === 'renderer-devtools') {
    try {
      return await proxyDesktopRequest<T>('GET', path)
    } catch (error) {
      if (!shouldFallbackToMainProcess(error)) {
        throw error
      }
      transportState.requestDebugMode = 'main-process'
    }
  }
  return getDesktopApiClient().get<T>(path)
}

async function desktopPost<T, B = unknown>(path: string, body?: B): Promise<T> {
  transportState.requestDebugMode = currentRequestDebugMode()
  if (transportState.requestDebugMode === 'renderer-devtools') {
    try {
      return await proxyDesktopRequest<T, B>('POST', path, body)
    } catch (error) {
      if (!shouldFallbackToMainProcess(error)) {
        throw error
      }
      transportState.requestDebugMode = 'main-process'
    }
  }
  return getDesktopApiClient().post<T, B>(path, body)
}

async function desktopDelete<T>(path: string): Promise<T> {
  transportState.requestDebugMode = currentRequestDebugMode()
  if (transportState.requestDebugMode === 'renderer-devtools') {
    try {
      return await proxyDesktopRequest<T>('DELETE', path)
    } catch (error) {
      if (!shouldFallbackToMainProcess(error)) {
        throw error
      }
      transportState.requestDebugMode = 'main-process'
    }
  }
  return getDesktopApiClient().remove<T>(path)
}

export function initTransport(): ApiClient {
  if (desktopApiClient) {
    return desktopApiClient
  }

  transportState.initializedAt = transportState.initializedAt || Date.now()
  transportState.baseURL = transportSession.baseURL
  transportState.requestDebugMode = currentRequestDebugMode()
  desktopApiClient = createDesktopClient(transportSession.baseURL)
  return desktopApiClient
}

export function configureTransport(
  session: DesktopRuntimeSessionSyncRequest | null,
): ApiClient | null {
  if (!session) {
    transportSession = {
      baseURL: normalizeDesktopApiBaseURL(process.env.DESKTOP_API_BASE_URL),
      clientToken: null,
    }
    transportState.baseURL = transportSession.baseURL
    transportState.requestDebugMode = currentRequestDebugMode()
    transportState.auth = 'pending'
    transportState.dispatchState = 'idle'
    desktopApiClient = null
    clearAccountUpsertCache()
    return null
  }

  transportSession = {
    baseURL: normalizeDesktopApiBaseURL(session.api_base_url),
    clientToken: session.client_token,
  }
  transportState.baseURL = transportSession.baseURL
  transportState.requestDebugMode = currentRequestDebugMode()
  transportState.auth = session.client_token ? 'registered' : 'pending'
  transportState.dispatchState = session.client_token ? 'connecting' : 'idle'
  transportState.initializedAt = Date.now()
  desktopApiClient = createDesktopClient(transportSession.baseURL)
  clearAccountUpsertCache()
  return desktopApiClient
}

export function setTransportAuthState(next: TransportAuthState): void {
  transportState.auth = next
}

export function setTransportDispatchState(next: TransportDispatchState): void {
  transportState.dispatchState = next
}

export function noteTransportHeartbeat(success: boolean): void {
  transportState.lastHeartbeatAt = Date.now()
  transportState.lastHeartbeatStatus = success ? 'success' : 'failed'
}

export function noteTransportPull(success: boolean): void {
  transportState.lastPullAt = Date.now()
  transportState.lastPullStatus = success ? 'success' : 'failed'
}

export function getDesktopApiClient(): ApiClient {
  return desktopApiClient ?? initTransport()
}

export function getTransportSnapshot() {
  return {
    ...transportState,
    hasClient: desktopApiClient !== null,
    hasClientToken: Boolean(transportSession.clientToken),
  }
}

export async function heartbeatDesktopClient(
  payload: DesktopClientHeartbeatRequest,
): Promise<DesktopClientHeartbeatResponse> {
  return desktopPost<DesktopClientHeartbeatResponse, DesktopClientHeartbeatRequest>(
    '/api/desktop/clients/heartbeat',
    payload,
  )
}

export async function rotateDesktopClient(): Promise<DesktopClientRotateResponse> {
  return desktopPost<DesktopClientRotateResponse, Record<string, never>>(
    '/api/desktop/clients/rotate',
    {},
  )
}

export async function checkDesktopClientRelease(params: {
  platform: string
  arch: string
  version: string
  channel?: string
}): Promise<DesktopClientReleaseCheckResponse> {
  const search = new URLSearchParams({
    platform: params.platform,
    arch: params.arch,
    version: params.version,
  })
  if (params.channel?.trim()) {
    search.set('channel', params.channel.trim())
  }
  return desktopGet<DesktopClientReleaseCheckResponse>(
    `/api/desktop/clients/releases/latest?${search.toString()}`,
  )
}

export async function resolveDesktopClientReleaseDownloadURL(params: {
  platform: string
  arch: string
  version: string
  channel?: string
}): Promise<{ download_url: string; expires_in?: number | null }> {
  const search = new URLSearchParams({
    platform: params.platform,
    arch: params.arch,
    version: params.version,
  })
  if (params.channel?.trim()) {
    search.set('channel', params.channel.trim())
  }
  return desktopGet<{ download_url: string; expires_in?: number | null }>(
    `/api/desktop/clients/releases/download-url?${search.toString()}`,
  )
}

export async function offlineDesktopClient(): Promise<void> {
  await desktopPost<{ server_time: string }, Record<string, never>>(
    '/api/desktop/clients/offline',
    {},
  )
}

export async function revokeDesktopClient(): Promise<void> {
  await desktopPost<{ id: string }, Record<string, never>>('/api/desktop/clients/revoke', {})
}

export async function listDesktopAccounts(): Promise<DesktopAccountInfo[]> {
  return desktopGet<DesktopAccountInfo[]>('/api/desktop/accounts')
}

export async function getDesktopArticleContent(articleId: number): Promise<DesktopArticleContent> {
  return desktopGet<DesktopArticleContent>(`/api/desktop/content/articles/${articleId}`)
}

export async function listDesktopPublishTasks(
  params: ListDesktopPublishTasksParams = {},
): Promise<DesktopPublishTaskListResponse> {
  const search = new URLSearchParams()
  if (params.page) {
    search.set('page', String(params.page))
  }
  if (params.page_size) {
    search.set('page_size', String(params.page_size))
  }
  if (params.title?.trim()) {
    search.set('title', params.title.trim())
  }

  const query = search.toString()
  const suffix = query ? `?${query}` : ''
  return desktopGet<DesktopPublishTaskListResponse>(`/api/desktop/publish-tasks${suffix}`)
}

export async function retryDesktopPublishTask(taskId: string): Promise<CreatePublishJobResponse> {
  return desktopPost<CreatePublishJobResponse, Record<string, never>>(
    `/api/desktop/publish-tasks/${encodeURIComponent(taskId)}/retry`,
    {},
  )
}

export async function upsertDesktopAccount(
  payload: UpsertDesktopAccountRequest,
): Promise<DesktopAccountInfo> {
  const now = Date.now()
  const cacheKey = accountUpsertCacheKey(payload)
  const signature = accountUpsertSignature(payload)
  const cached = accountUpsertCache.get(cacheKey)
  if (cached && cached.signature === signature && cached.expiresAt > now) {
    if (cached.inFlight) {
      return cached.inFlight
    }
    return cached.response
  }

  const request = desktopPost<DesktopAccountInfo, UpsertDesktopAccountRequest>(
    '/api/desktop/accounts',
    payload,
  )
  accountUpsertCache.set(cacheKey, {
    signature,
    expiresAt: now + ACCOUNT_UPSERT_CACHE_TTL_MS,
    response: cached?.response ?? ({} as DesktopAccountInfo),
    inFlight: request,
  })

  try {
    const response = await request
    accountUpsertCache.set(cacheKey, {
      signature,
      expiresAt: Date.now() + ACCOUNT_UPSERT_CACHE_TTL_MS,
      response,
      inFlight: null,
    })
    return response
  } catch (error) {
    if (accountUpsertCache.get(cacheKey)?.inFlight === request) {
      accountUpsertCache.delete(cacheKey)
    }
    appendAccountUpsertDiagnostic(payload, error)
    throw error
  }
}

export async function reportDesktopAccountHealth(
  payload: ReportDesktopAccountHealthRequest,
): Promise<ReportDesktopAccountHealthResponse> {
  return desktopPost<ReportDesktopAccountHealthResponse, ReportDesktopAccountHealthRequest>(
    '/api/desktop/accounts/health-reports',
    payload,
  )
}

export async function deleteDesktopAccount(
  desktopId: string,
  ifSyncVersion: number,
): Promise<DesktopAccountInfo> {
  const params = new URLSearchParams({ if_sync_version: String(ifSyncVersion) })
  const response = await desktopDelete<DesktopAccountInfo>(
    `/api/desktop/accounts/${encodeURIComponent(desktopId)}?${params.toString()}`,
  )
  clearAccountUpsertCache()
  return response
}

export async function leaseDesktopTask(
  request: LeaseDesktopTaskRequest,
): Promise<LeaseDesktopTaskResponse> {
  const taskId = request.task_id?.trim()
  const path = taskId ? `/api/desktop/tasks/${taskId}/lease` : '/api/desktop/tasks/lease'
  return desktopPost<LeaseDesktopTaskResponse, LeaseDesktopTaskRequest>(
    path,
    taskId ? { kind: request.kind } : request,
  )
}

export async function extendDesktopTask(
  taskId: string,
  payload: ExtendDesktopTaskRequest,
): Promise<DesktopTaskInfo> {
  return desktopPost<DesktopTaskInfo, ExtendDesktopTaskRequest>(
    `/api/desktop/tasks/${taskId}/extend`,
    payload,
  )
}

export async function completeDesktopTask(
  taskId: string,
  payload: CompleteDesktopTaskRequest,
): Promise<DesktopTaskInfo> {
  return desktopPost<DesktopTaskInfo, CompleteDesktopTaskRequest>(
    `/api/desktop/tasks/${taskId}/result`,
    payload,
  )
}

export async function markDesktopTaskPublishSubmitStarted(
  taskId: string,
  leaseToken: string,
): Promise<void> {
  await desktopPost<{ ok: boolean }, { lease_token: string }>(
    `/api/desktop/tasks/${taskId}/publish-submit-marker`,
    { lease_token: leaseToken },
  )
}

export async function cancelDesktopTask(
  taskId: string,
  payload: CancelDesktopTaskRequest,
): Promise<DesktopTaskInfo> {
  return desktopPost<DesktopTaskInfo, CancelDesktopTaskRequest>(
    `/api/desktop/tasks/${taskId}/cancel`,
    payload,
  )
}

export async function leaseMonitoringTasks(
  payload: MonitoringLeaseTasksPayload = {},
): Promise<MonitoringLeaseTasksResponse> {
  return desktopPost<MonitoringLeaseTasksResponse, MonitoringLeaseTasksPayload>(
    '/api/desktop/monitoring/tasks/lease',
    payload,
  )
}

export async function resumeMonitoringTasks(
  payload: MonitoringResumeTasksPayload = {},
): Promise<MonitoringResumeTasksResponse> {
  return desktopPost<MonitoringResumeTasksResponse, MonitoringResumeTasksPayload>(
    '/api/desktop/monitoring/tasks/resume',
    payload,
  )
}

export async function submitMonitoringTaskResult(
  taskId: number,
  payload: MonitoringTaskResultPayload,
): Promise<MonitoringTaskResultResponse> {
  return desktopPost<MonitoringTaskResultResponse, MonitoringTaskResultPayload>(
    `/api/desktop/monitoring/tasks/${taskId}/result`,
    payload,
  )
}

export async function skipMonitoringTask(
  taskId: number,
  payload: MonitoringSkipTaskPayload,
): Promise<MonitoringSkipTaskResponse> {
  return desktopPost<MonitoringSkipTaskResponse, MonitoringSkipTaskPayload>(
    `/api/desktop/monitoring/tasks/${taskId}/skip`,
    payload,
  )
}

export async function cancelMonitoringTask(
  taskId: number,
  payload: MonitoringCancelTaskPayload,
): Promise<MonitoringCancelTaskResponse> {
  return desktopPost<MonitoringCancelTaskResponse, MonitoringCancelTaskPayload>(
    `/api/desktop/monitoring/tasks/${taskId}/cancel`,
    payload,
  )
}