/**
 * Provider Service — preset-based provider configuration
 *
 * Storage: ~/.claude/cc-haha/providers.json (lightweight index)
 * Active provider env vars written to ~/.claude/cc-haha/settings.json
 * (isolated from the original Claude Code's ~/.claude/settings.json)
 */

import * as fs from 'fs/promises'
import * as path from 'path'
import * as os from 'os'
import { ApiError } from '../middleware/errorHandler.js'
import { readRecoverableJsonFile } from './recoverableJsonFile.js'
import { ManagedSettingsService } from './managedSettingsService.js'
import { anthropicToOpenaiChat } from '../proxy/transform/anthropicToOpenaiChat.js'
import { anthropicToOpenaiResponses } from '../proxy/transform/anthropicToOpenaiResponses.js'
import { openaiChatToAnthropic } from '../proxy/transform/openaiChatToAnthropic.js'
import { openaiResponsesToAnthropic } from '../proxy/transform/openaiResponsesToAnthropic.js'
import type { AnthropicRequest, AnthropicResponse } from '../proxy/transform/types.js'
import {
  OPENAI_OFFICIAL_PROVIDER,
  isOpenAIOfficialProviderId,
} from './openaiOfficialProvider.js'
import { hahaOpenAIOAuthService } from './hahaOpenAIOAuthService.js'
import {
  CURRENT_PROVIDER_INDEX_SCHEMA_VERSION,
  ensurePersistentStorageUpgraded,
} from './persistentStorageMigrations.js'
import {
  buildProviderAuthEnv,
  buildProviderManagedEnv,
  getManagedEnvKeys,
  getPresetAuthStrategy,
  getPresetDefaultEnv,
  normalizeModelMapping,
  normalizeProvidersIndex,
} from './providerRuntimeEnv.js'
import { getProxyFetchOptions } from '../../utils/proxy.js'
import {
  getManualNetworkProxyUrl,
  loadNetworkSettings,
  mergeLoopbackNoProxy,
  type NetworkSettings,
} from './networkSettings.js'
import { normalizeModelStringForAPI } from '../../utils/model/model.js'
import type {
  SavedProvider,
  ProvidersIndex,
  CreateProviderInput,
  UpdateProviderInput,
  TestProviderInput,
  ProviderTestResult,
  ProviderTestStepResult,
  ApiFormat,
  ProviderAuthStrategy,
} from '../types/provider.js'
import {
  BUILT_IN_PROVIDER_IDS,
} from '../types/provider.js'

const DEFAULT_INDEX: ProvidersIndex = {
  schemaVersion: CURRENT_PROVIDER_INDEX_SCHEMA_VERSION,
  activeId: null,
  providers: [],
  providerOrder: [...BUILT_IN_PROVIDER_IDS],
}

function isPermutation(candidateIds: string[], expectedIds: string[]): boolean {
  const expectedSet = new Set(expectedIds)
  const candidateSet = new Set(candidateIds)
  return (
    candidateIds.length === expectedIds.length &&
    candidateSet.size === candidateIds.length &&
    expectedIds.every((id) => candidateSet.has(id)) &&
    candidateIds.every((id) => expectedSet.has(id))
  )
}

function savedProviderIds(providers: SavedProvider[]): string[] {
  return providers.map((provider) => provider.id)
}

function fullProviderOrderIds(providers: SavedProvider[]): string[] {
  return [
    ...savedProviderIds(providers),
    ...BUILT_IN_PROVIDER_IDS,
  ]
}

function sortSavedProvidersByOrder(providers: SavedProvider[], providerOrder: string[]): SavedProvider[] {
  const byId = new Map(providers.map((provider) => [provider.id, provider]))
  return providerOrder
    .map((id) => byId.get(id))
    .filter((provider): provider is SavedProvider => provider !== undefined)
}

function mergeSavedOrderIntoDisplayOrder(providerOrder: string[], savedOrder: string[]): string[] {
  const savedSet = new Set(savedOrder)
  const queue = [...savedOrder]
  return providerOrder.map((id) => {
    if (!savedSet.has(id)) return id
    return queue.shift() ?? id
  })
}

function appendNewProviderToOrder(providerOrder: string[], providerId: string, existingProviders: SavedProvider[]): string[] {
  const existingProviderIds = new Set(existingProviders.map((provider) => provider.id))
  const lastSavedIndex = providerOrder.reduce(
    (latest, id, index) => existingProviderIds.has(id) ? index : latest,
    -1,
  )
  if (lastSavedIndex !== -1) {
    return [
      ...providerOrder.slice(0, lastSavedIndex + 1),
      providerId,
      ...providerOrder.slice(lastSavedIndex + 1),
    ]
  }

  const firstBuiltInIndex = providerOrder.findIndex((id) => BUILT_IN_PROVIDER_IDS.includes(id as typeof BUILT_IN_PROVIDER_IDS[number]))
  if (firstBuiltInIndex === -1) return [...providerOrder, providerId]
  return [
    ...providerOrder.slice(0, firstBuiltInIndex),
    providerId,
    ...providerOrder.slice(firstBuiltInIndex),
  ]
}

export class ProviderService {
  private static serverPort = 3456
  private managedSettingsService = new ManagedSettingsService()

  static setServerPort(port: number): void {
    ProviderService.serverPort = port
  }

  static getServerPort(): number {
    return ProviderService.serverPort
  }
  private getConfigDir(): string {
    return process.env.CLAUDE_CONFIG_DIR || path.join(os.homedir(), '.claude')
  }

  private getCcHahaDir(): string {
    return path.join(this.getConfigDir(), 'cc-haha')
  }

  private getIndexPath(): string {
    return path.join(this.getCcHahaDir(), 'providers.json')
  }

  private async readIndex(): Promise<ProvidersIndex> {
    await ensurePersistentStorageUpgraded()
    return readRecoverableJsonFile({
      filePath: this.getIndexPath(),
      label: 'providers index',
      defaultValue: DEFAULT_INDEX,
      normalize: normalizeProvidersIndex,
    })
  }

  private async writeIndex(index: ProvidersIndex): Promise<void> {
    const filePath = this.getIndexPath()
    const dir = path.dirname(filePath)
    await fs.mkdir(dir, { recursive: true })

    const tmpFile = `${filePath}.tmp.${Date.now()}`
    try {
      await fs.writeFile(tmpFile, JSON.stringify(index, null, 2) + '\n', 'utf-8')
      await fs.rename(tmpFile, filePath)
    } catch (err) {
      await fs.unlink(tmpFile).catch(() => {})
      throw ApiError.internal(`Failed to write providers index: ${err}`)
    }
  }

  private async readSettings(): Promise<Record<string, unknown>> {
    return this.managedSettingsService.readSettings()
  }

  async getManagedSettings(): Promise<Record<string, unknown>> {
    return this.readSettings()
  }

  async updateManagedSettings(settings: Record<string, unknown>): Promise<void> {
    await this.managedSettingsService.updateSettings((current) => ({
      settings: Object.assign({}, current, settings),
      result: undefined,
    }))
  }

  // --- CRUD ---

  async listProviders(): Promise<{ providers: SavedProvider[]; activeId: string | null; providerOrder: string[] }> {
    const index = await this.readIndex()
    return {
      providers: index.providers,
      activeId: index.activeId,
      providerOrder: index.providerOrder,
    }
  }

  async getProvider(id: string): Promise<SavedProvider> {
    if (isOpenAIOfficialProviderId(id)) {
      return OPENAI_OFFICIAL_PROVIDER
    }

    const index = await this.readIndex()
    const provider = index.providers.find((p) => p.id === id)
    if (!provider) throw ApiError.notFound(`Provider not found: ${id}`)
    return provider
  }

  async addProvider(input: CreateProviderInput): Promise<SavedProvider> {
    const index = await this.readIndex()

    const provider: SavedProvider = {
      id: crypto.randomUUID(),
      presetId: input.presetId,
      name: input.name,
      apiKey: input.apiKey,
      ...(input.authStrategy !== undefined && { authStrategy: input.authStrategy }),
      baseUrl: input.baseUrl,
      apiFormat: input.apiFormat ?? 'anthropic',
      runtimeKind: input.runtimeKind ?? 'anthropic_compatible',
      models: normalizeModelMapping(input.models),
      ...(input.model1mSupport !== undefined && { model1mSupport: input.model1mSupport }),
      ...(input.autoCompactWindow !== undefined && { autoCompactWindow: input.autoCompactWindow }),
      ...(input.modelContextWindows !== undefined && { modelContextWindows: input.modelContextWindows }),
      toolSearchEnabled: input.toolSearchEnabled ?? true,
      ...(input.notes !== undefined && { notes: input.notes }),
    }

    index.providerOrder = appendNewProviderToOrder(index.providerOrder, provider.id, index.providers)
    index.providers.push(provider)
    await this.writeIndex(index)
    return provider
  }

  async updateProvider(id: string, input: UpdateProviderInput): Promise<SavedProvider> {
    const index = await this.readIndex()
    const idx = index.providers.findIndex((p) => p.id === id)
    if (idx === -1) throw ApiError.notFound(`Provider not found: ${id}`)

    const existing = index.providers[idx]
    const updated: SavedProvider = {
      ...existing,
      ...(input.name !== undefined && { name: input.name }),
      ...(input.apiKey !== undefined && { apiKey: input.apiKey }),
      ...(input.authStrategy !== undefined && { authStrategy: input.authStrategy }),
      ...(input.baseUrl !== undefined && { baseUrl: input.baseUrl }),
      ...(input.apiFormat !== undefined && { apiFormat: input.apiFormat }),
      ...(input.runtimeKind !== undefined && { runtimeKind: input.runtimeKind }),
      ...(input.models !== undefined && { models: normalizeModelMapping(input.models) }),
      ...(input.model1mSupport !== undefined && input.model1mSupport !== null && { model1mSupport: input.model1mSupport }),
      ...(typeof input.autoCompactWindow === 'number' && { autoCompactWindow: input.autoCompactWindow }),
      ...(input.modelContextWindows !== undefined && input.modelContextWindows !== null && { modelContextWindows: input.modelContextWindows }),
      ...(input.toolSearchEnabled !== undefined && { toolSearchEnabled: input.toolSearchEnabled }),
      ...(input.notes !== undefined && { notes: input.notes }),
    }
    if (input.model1mSupport === null) {
      delete updated.model1mSupport
    }
    if (input.autoCompactWindow === null) {
      delete updated.autoCompactWindow
    }
    if (input.modelContextWindows === null) {
      delete updated.modelContextWindows
    }

    index.providers[idx] = updated
    await this.writeIndex(index)

    if (index.activeId === id) {
      await this.syncToSettings(updated)
    }

    return updated
  }

  async deleteProvider(id: string): Promise<void> {
    const index = await this.readIndex()
    const idx = index.providers.findIndex((p) => p.id === id)
    if (idx === -1) throw ApiError.notFound(`Provider not found: ${id}`)

    if (index.activeId === id) {
      throw ApiError.conflict('Cannot delete the active provider. Switch to another provider first.')
    }

    index.providers.splice(idx, 1)
    index.providerOrder = index.providerOrder.filter((providerId) => providerId !== id)
    await this.writeIndex(index)
  }

  /**
   * Reorder providers to match the given display id order.
   *
   * New clients send a full display-order permutation including the built-in
   * official providers. Legacy clients may still send only saved provider ids;
   * in that case the saved providers are reordered inside the current display
   * order without moving the built-in official rows.
   */
  async reorderProviders(orderedIds: string[]): Promise<{ providers: SavedProvider[]; providerOrder: string[] }> {
    const index = await this.readIndex()

    const currentSavedIds = savedProviderIds(index.providers)
    const isFullDisplayPermutation = isPermutation(orderedIds, fullProviderOrderIds(index.providers))
    const isLegacySavedPermutation = isPermutation(orderedIds, currentSavedIds)

    if (!isFullDisplayPermutation && !isLegacySavedPermutation) {
      throw ApiError.badRequest('orderedIds must be a permutation of existing provider ids and built-in provider ids')
    }

    index.providerOrder = isFullDisplayPermutation
      ? orderedIds
      : mergeSavedOrderIntoDisplayOrder(index.providerOrder, orderedIds)
    index.providers = sortSavedProvidersByOrder(index.providers, index.providerOrder)
    await this.writeIndex(index)

    return {
      providers: index.providers,
      providerOrder: index.providerOrder,
    }
  }

  // --- Activation ---

  async activateProvider(id: string): Promise<void> {
    const index = await this.readIndex()
    const provider = isOpenAIOfficialProviderId(id)
      ? OPENAI_OFFICIAL_PROVIDER
      : index.providers.find((p) => p.id === id)
    if (!provider) throw ApiError.notFound(`Provider not found: ${id}`)

    index.activeId = id
    await this.writeIndex(index)

    if (provider.runtimeKind === 'openai_oauth') {
      await this.syncToSettings(provider)
    } else if (provider.presetId === 'official') {
      await this.clearProviderFromSettings()
    } else {
      await this.syncToSettings(provider)
    }
  }

  async activateOfficial(): Promise<void> {
    const index = await this.readIndex()
    index.activeId = null
    await this.writeIndex(index)
    await this.clearProviderFromSettings()
  }

  // --- Settings sync ---

  private buildManagedEnv(
    provider: SavedProvider,
    options?: { proxyPath?: string },
  ): Record<string, string> {
    return buildProviderManagedEnv(provider, {
      proxyPath: options?.proxyPath,
      serverPort: ProviderService.serverPort,
    })
  }

  async getProviderRuntimeEnv(id: string): Promise<Record<string, string>> {
    const provider = await this.getProvider(id)
    return this.buildManagedEnv(provider, {
      proxyPath: `/proxy/providers/${provider.id}`,
    })
  }

  private async syncToSettings(provider: SavedProvider): Promise<void> {
    await this.managedSettingsService.updateSettings((settings) => {
      const existingEnv = (settings.env as Record<string, string>) || {}
      const cleanedEnv = { ...existingEnv }

      for (const key of getManagedEnvKeys()) {
        delete cleanedEnv[key]
      }

      return {
        settings: {
          ...settings,
          env: {
            ...cleanedEnv,
            ...this.buildManagedEnv(provider),
          },
        },
        result: undefined,
      }
    })
  }

  private async clearProviderFromSettings(): Promise<void> {
    await this.managedSettingsService.updateSettings((settings) => {
      const env = { ...((settings.env as Record<string, string>) || {}) }

      for (const key of getManagedEnvKeys()) {
        delete env[key]
      }

      const nextSettings: Record<string, unknown> = {
        ...settings,
      }

      if (Object.keys(env).length === 0) {
        delete nextSettings.env
      } else {
        nextSettings.env = env
      }

      return {
        settings: nextSettings,
        result: undefined,
      }
    })
  }

  // --- Auth status ---

  /**
   * Check whether any usable auth exists:
   *  1. A cc-haha provider is active → has auth
   *  2. Original ~/.claude/settings.json has ANTHROPIC_AUTH_TOKEN or ANTHROPIC_API_KEY → has auth
   *  3. process.env already has ANTHROPIC_API_KEY / ANTHROPIC_AUTH_TOKEN → has auth
   *  4. None of the above → needs setup
   */
  async checkAuthStatus(): Promise<{
    hasAuth: boolean
    source: 'cc-haha-provider' | 'openai-oauth' | 'original-settings' | 'env' | 'none'
    activeProvider?: string
  }> {
    // 1. Check cc-haha active provider
    const index = await this.readIndex()
    if (index.activeId) {
      if (isOpenAIOfficialProviderId(index.activeId)) {
        const tokens = await hahaOpenAIOAuthService.ensureFreshTokens()
        if (tokens?.accessToken && tokens.refreshToken) {
          return {
            hasAuth: true,
            source: 'openai-oauth',
            activeProvider: OPENAI_OFFICIAL_PROVIDER.name,
          }
        }
        return {
          hasAuth: false,
          source: 'none',
          activeProvider: OPENAI_OFFICIAL_PROVIDER.name,
        }
      }

      const provider = index.providers.find(p => p.id === index.activeId)
      if (provider) {
        const presetDefaultEnv = getPresetDefaultEnv(provider.presetId)
        const needsProxy = provider.apiFormat != null && provider.apiFormat !== 'anthropic'
        const authEnv = buildProviderAuthEnv(provider, presetDefaultEnv, needsProxy)
        if (Object.values(authEnv).some(value => value.length > 0)) {
          return { hasAuth: true, source: 'cc-haha-provider', activeProvider: provider.name }
        }
      }
    }

    // 2. Check process.env (covers .env file + inherited env)
    if (process.env.ANTHROPIC_API_KEY || process.env.ANTHROPIC_AUTH_TOKEN) {
      return { hasAuth: true, source: 'env' }
    }

    // 3. Check original ~/.claude/settings.json
    try {
      const originalPath = path.join(this.getConfigDir(), 'settings.json')
      const raw = await fs.readFile(originalPath, 'utf-8')
      const settings = JSON.parse(raw) as { env?: Record<string, string> }
      const env = settings.env ?? {}
      if (env.ANTHROPIC_AUTH_TOKEN || env.ANTHROPIC_API_KEY) {
        return { hasAuth: true, source: 'original-settings' }
      }
    } catch {
      // File doesn't exist or invalid
    }

    return { hasAuth: false, source: 'none' }
  }

  // --- Proxy support ---

  async getProviderForProxy(providerId?: string): Promise<{
    id: string
    name: string
    baseUrl: string
    apiKey: string
    apiFormat: ApiFormat
  } | null> {
    if (providerId) {
      if (isOpenAIOfficialProviderId(providerId)) {
        return null
      }
      const provider = await this.getProvider(providerId)
      return {
        id: provider.id,
        name: provider.name,
        baseUrl: provider.baseUrl,
        apiKey: provider.apiKey,
        apiFormat: provider.apiFormat ?? 'anthropic',
      }
    }

    const index = await this.readIndex()
    if (!index.activeId) return null
    if (isOpenAIOfficialProviderId(index.activeId)) {
      return null
    }
    const provider = await this.getProvider(index.activeId).catch(() => null)
    if (!provider) return null
    return {
      id: provider.id,
      name: provider.name,
      baseUrl: provider.baseUrl,
      apiKey: provider.apiKey,
      apiFormat: provider.apiFormat ?? 'anthropic',
    }
  }

  async getActiveProviderForProxy(): Promise<{
    baseUrl: string
    apiKey: string
    apiFormat: ApiFormat
  } | null> {
    return this.getProviderForProxy()
  }

  // --- Test ---

  async testProvider(
    id: string,
    overrides?: { baseUrl?: string; modelId?: string; apiFormat?: ApiFormat; authStrategy?: ProviderAuthStrategy },
  ): Promise<ProviderTestResult> {
    const provider = await this.getProvider(id)
    const baseUrl = overrides?.baseUrl || provider.baseUrl
    const modelId = overrides?.modelId || provider.models.main
    const apiFormat = overrides?.apiFormat ?? provider.apiFormat ?? 'anthropic'
    const authStrategy = overrides?.authStrategy ?? provider.authStrategy ?? getPresetAuthStrategy(provider.presetId)
    const presetDefaultEnv = getPresetDefaultEnv(provider.presetId)
    const apiKey = provider.apiKey
      || presetDefaultEnv.ANTHROPIC_AUTH_TOKEN
      || presetDefaultEnv.ANTHROPIC_API_KEY
      || (authStrategy === 'dual_dummy' ? 'dummy' : '')

    if (!baseUrl || !apiKey) {
      return { connectivity: { success: false, latencyMs: 0, error: 'Missing baseUrl or apiKey' } }
    }
    return this.testProviderConfig({
      baseUrl,
      apiKey,
      modelId,
      authStrategy,
      apiFormat,
    })
  }

  async testProviderConfig(input: TestProviderInput): Promise<ProviderTestResult> {
    const format: ApiFormat = input.apiFormat ?? 'anthropic'
    const authStrategy = input.authStrategy ?? 'api_key'
    const base = input.baseUrl.replace(/\/+$/, '')
    const modelId = normalizeModelStringForAPI(input.modelId)
    const networkSettings = await loadNetworkSettings()

    // ── Step 1: Basic connectivity ───────────────────────────
    // Directly call the upstream API to verify URL, key, and model.
    const step1 = await this.testConnectivity(base, input.apiKey, modelId, format, authStrategy, networkSettings)

    // If connectivity failed, no point running step 2
    if (!step1.success) {
      return { connectivity: step1 }
    }

    // For native Anthropic format, no proxy pipeline to test
    if (format === 'anthropic') {
      return { connectivity: step1 }
    }

    // ── Step 2: Full proxy pipeline ──────────────────────────
    // Anthropic request → transform → upstream → transform back → validate
    const step2 = await this.testProxyPipeline(base, input.apiKey, modelId, format, networkSettings)

    return { connectivity: step1, proxy: step2 }
  }

  /** Step 1: Direct upstream call to verify connectivity, auth, and model. */
  private async testConnectivity(
    base: string,
    apiKey: string,
    modelId: string,
    format: ApiFormat,
    authStrategy: ProviderAuthStrategy,
    networkSettings: NetworkSettings,
  ): Promise<ProviderTestStepResult> {
    const start = Date.now()
    try {
      const { url, headers, body } = buildDirectTestRequest(base, apiKey, modelId, format, authStrategy)
      const proxyOptions = getProxyFetchOptions({
        proxyUrl: getManualNetworkProxyUrl(networkSettings),
        targetUrl: url,
        noProxy: mergeLoopbackNoProxy(process.env.no_proxy || process.env.NO_PROXY),
      })
      const response = await fetch(url, {
        method: 'POST',
        headers,
        body: JSON.stringify(body),
        signal: AbortSignal.timeout(networkSettings.aiRequestTimeoutMs),
        ...proxyOptions,
      })

      const latencyMs = Date.now() - start
      const resBody = await response.json().catch(() => null) as Record<string, unknown> | null

      if (!response.ok) {
        let error = `HTTP ${response.status}`
        if (resBody?.error && typeof resBody.error === 'object') {
          error = ((resBody.error as Record<string, unknown>).message as string) || error
        }
        return { success: false, latencyMs, error, modelUsed: modelId, httpStatus: response.status }
      }

      // Validate response structure
      const valid = validateResponseBody(resBody, format)
      if (!valid.ok) {
        return { success: false, latencyMs, error: valid.error, modelUsed: modelId, httpStatus: response.status }
      }

      return { success: true, latencyMs, modelUsed: valid.model || modelId, httpStatus: response.status }
    } catch (err: unknown) {
      const latencyMs = Date.now() - start
      if (err instanceof DOMException && err.name === 'TimeoutError') {
        return { success: false, latencyMs, error: `Request timed out (${Math.round(networkSettings.aiRequestTimeoutMs / 1000)}s)`, modelUsed: modelId }
      }
      return { success: false, latencyMs, error: err instanceof Error ? err.message : String(err), modelUsed: modelId }
    }
  }

  /** Step 2: Full proxy pipeline — Anthropic → transform → upstream → transform back → validate. */
  private async testProxyPipeline(
    base: string,
    apiKey: string,
    modelId: string,
    format: 'openai_chat' | 'openai_responses',
    networkSettings: NetworkSettings,
  ): Promise<ProviderTestStepResult> {
    const start = Date.now()
    try {
      // Build an Anthropic Messages API request (same shape as what CLI sends)
      const anthropicReq: AnthropicRequest = {
        model: modelId,
        max_tokens: 64,
        messages: [{ role: 'user', content: 'Say "ok" and nothing else.' }],
      }

      // Transform to OpenAI format
      let upstreamUrl: string
      let transformedBody: unknown
      if (format === 'openai_chat') {
        transformedBody = anthropicToOpenaiChat(anthropicReq)
        upstreamUrl = `${base}/v1/chat/completions`
      } else {
        transformedBody = anthropicToOpenaiResponses(anthropicReq)
        upstreamUrl = `${base}/v1/responses`
      }
      const proxyOptions = getProxyFetchOptions({
        proxyUrl: getManualNetworkProxyUrl(networkSettings),
        targetUrl: upstreamUrl,
        noProxy: mergeLoopbackNoProxy(process.env.no_proxy || process.env.NO_PROXY),
      })

      // Call upstream with transformed request
      const response = await fetch(upstreamUrl, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json', Authorization: `Bearer ${apiKey}` },
        body: JSON.stringify(transformedBody),
        signal: AbortSignal.timeout(networkSettings.aiRequestTimeoutMs),
        ...proxyOptions,
      })

      if (!response.ok) {
        const latencyMs = Date.now() - start
        const errText = await response.text().catch(() => '')
        return { success: false, latencyMs, modelUsed: modelId, httpStatus: response.status,
          error: `Upstream HTTP ${response.status}: ${errText.slice(0, 200)}` }
      }

      // Transform response back to Anthropic format
      const responseBody = await response.json()
      const anthropicRes = format === 'openai_chat'
        ? openaiChatToAnthropic(responseBody, modelId)
        : openaiResponsesToAnthropic(responseBody, modelId)

      const latencyMs = Date.now() - start

      // Validate the final Anthropic response
      if (anthropicRes.type !== 'message' || !Array.isArray(anthropicRes.content)) {
        return { success: false, latencyMs, modelUsed: modelId,
          error: 'Proxy transform produced invalid Anthropic response' }
      }

      return { success: true, latencyMs, modelUsed: anthropicRes.model || modelId, httpStatus: response.status }
    } catch (err: unknown) {
      const latencyMs = Date.now() - start
      if (err instanceof DOMException && err.name === 'TimeoutError') {
        return { success: false, latencyMs, error: `Proxy pipeline timed out (${Math.round(networkSettings.aiRequestTimeoutMs / 1000)}s)`, modelUsed: modelId }
      }
      return { success: false, latencyMs, error: err instanceof Error ? err.message : String(err), modelUsed: modelId }
    }
  }
}

// ─── Helpers ───────────────────────────────────────────────

function buildDirectTestRequest(
  base: string,
  apiKey: string,
  modelId: string,
  format: ApiFormat,
  authStrategy: ProviderAuthStrategy,
): { url: string; headers: Record<string, string>; body: Record<string, unknown> } {
  const prompt = 'Say "ok" and nothing else.'

  if (format === 'openai_chat') {
    return {
      url: `${base}/v1/chat/completions`,
      headers: { 'Content-Type': 'application/json', Authorization: `Bearer ${apiKey}` },
      body: { model: modelId, max_tokens: 16, stream: false, messages: [{ role: 'user', content: prompt }] },
    }
  }
  if (format === 'openai_responses') {
    return {
      url: `${base}/v1/responses`,
      headers: { 'Content-Type': 'application/json', Authorization: `Bearer ${apiKey}` },
      body: { model: modelId, max_output_tokens: 16, input: [{ type: 'message', role: 'user', content: prompt }] },
    }
  }
  // anthropic
  return {
    url: `${base}/v1/messages`,
    headers: {
      'Content-Type': 'application/json',
      'anthropic-version': '2023-06-01',
      ...buildAnthropicAuthHeaders(apiKey, authStrategy),
    },
    body: { model: modelId, max_tokens: 16, messages: [{ role: 'user', content: prompt }] },
  }
}

function buildAnthropicAuthHeaders(apiKey: string, authStrategy: ProviderAuthStrategy): Record<string, string> {
  switch (authStrategy) {
    case 'api_key':
      return { 'x-api-key': apiKey }
    case 'auth_token':
    case 'auth_token_empty_api_key':
      return { Authorization: `Bearer ${apiKey}` }
    case 'dual_same_token':
      return { 'x-api-key': apiKey, Authorization: `Bearer ${apiKey}` }
    case 'dual_dummy':
      return { 'x-api-key': 'dummy', Authorization: 'Bearer dummy' }
  }
}

function validateResponseBody(
  body: Record<string, unknown> | null,
  format: ApiFormat,
): { ok: true; model?: string } | { ok: false; error: string } {
  if (!body) return { ok: false, error: 'Empty response — not a valid API endpoint' }
  if (body.error && typeof body.error === 'object') {
    return { ok: false, error: ((body.error as Record<string, unknown>).message as string) || 'Error in response body' }
  }

  if (format === 'openai_chat') {
    if (!Array.isArray(body.choices) || body.choices.length === 0) {
      return { ok: false, error: 'Response missing choices — not a valid Chat Completions endpoint' }
    }
    return { ok: true, model: (body.model as string) || undefined }
  }
  if (format === 'openai_responses') {
    if (!Array.isArray(body.output)) {
      return { ok: false, error: 'Response missing output — not a valid Responses API endpoint' }
    }
    return { ok: true, model: (body.model as string) || undefined }
  }
  // anthropic
  if (body.type !== 'message' || !Array.isArray(body.content)) {
    return { ok: false, error: 'Not a valid Anthropic Messages endpoint' }
  }
  return { ok: true, model: (body.model as string) || undefined }
}