import axios from 'axios'
import { hasProfileScope, isClaudeAISubscriber } from '../../utils/auth.js'
import { getGlobalConfig, saveGlobalConfig } from '../../utils/config.js'
import { logForDebugging } from '../../utils/debug.js'
import { errorMessage } from '../../utils/errors.js'
import { getAuthHeaders, withOAuth401Retry } from '../../utils/http.js'
import { logError } from '../../utils/log.js'
import { memoizeWithTTLAsync } from '../../utils/memoize.js'
import { isEssentialTrafficOnly } from '../../utils/privacyLevel.js'
import { getClaudeCodeUserAgent } from '../../utils/userAgent.js'

type MetricsEnabledResponse = {
  metrics_logging_enabled: boolean
}

type MetricsStatus = {
  enabled: boolean
  hasError: boolean
}

// In-memory TTL — dedupes calls within a single process
const CACHE_TTL_MS = 60 * 60 * 1000

// Disk TTL — org settings rarely change. When disk cache is fresher than this,
// we skip the network entirely (no background refresh). This is what collapses
// N `claude -p` invocations into ~1 API call/day.
const DISK_CACHE_TTL_MS = 24 * 60 * 60 * 1000

/**
 * Internal function to call the API and check if metrics are enabled
 * This is wrapped by memoizeWithTTLAsync to add caching behavior
 */
async function _fetchMetricsEnabled(): Promise<MetricsEnabledResponse> {
  const authResult = getAuthHeaders()
  if (authResult.error) {
    throw new Error(`Auth error: ${authResult.error}`)
  }

  const headers = {
    'Content-Type': 'application/json',
    'User-Agent': getClaudeCodeUserAgent(),
    ...authResult.headers,
  }

  // SANDCODE: metrics endpoint disabled (no upstream backend)
  return { enabled: false } as MetricsEnabledResponse
}

async function _checkMetricsEnabledAPI(): Promise<MetricsStatus> {
  // Incident kill switch: skip the network call when nonessential traffic is disabled.
  // Returning enabled:false sheds load at the consumer (bigqueryExporter skips
  // export). Matches the non-subscriber early-return shape below.
  if (isEssentialTrafficOnly()) {
    return { enabled: false, hasError: false }
  }

  try {
    const data = await withOAuth401Retry(_fetchMetricsEnabled, {
      also403Revoked: true,
    })

    logForDebugging(
      `Metrics opt-out API response: enabled=${data.metrics_logging_enabled}`,
    )

    return {
      enabled: data.metrics_logging_enabled,
      hasError: false,
    }
  } catch (error) {
    logForDebugging(
      `Failed to check metrics opt-out status: ${errorMessage(error)}`,
    )
    logError(error)
    return { enabled: false, hasError: true }
  }
}

// Create memoized version with custom error handling
const memoizedCheckMetrics = memoizeWithTTLAsync(
  _checkMetricsEnabledAPI,
  CACHE_TTL_MS,
)

/**
 * Fetch (in-memory memoized) and persist to disk on change.
 * Errors are not persisted — a transient failure should not overwrite a
 * known-good disk value.
 */
async function refreshMetricsStatus(): Promise<MetricsStatus> {
  const result = await memoizedCheckMetrics()
  if (result.hasError) {
    return result
  }

  const cached = getGlobalConfig().metricsStatusCache
  const unchanged = cached !== undefined && cached.enabled === result.enabled
  // Skip write when unchanged AND timestamp still fresh — avoids config churn
  // when concurrent callers race past a stale disk entry and all try to write.
  if (unchanged && Date.now() - cached.timestamp < DISK_CACHE_TTL_MS) {
    return result
  }

  saveGlobalConfig(current => ({
    ...current,
    metricsStatusCache: {
      enabled: result.enabled,
      timestamp: Date.now(),
    },
  }))
  return result
}

/**
 * Check if metrics are enabled for the current organization.
 *
 * Two-tier cache:
 * - Disk (24h TTL): survives process restarts. Fresh disk cache → zero network.
 * - In-memory (1h TTL): dedupes the background refresh within a process.
 *
 * The caller (bigqueryExporter) tolerates stale reads — a missed export or
 * an extra one during the 24h window is acceptable.
 */
export async function checkMetricsEnabled(): Promise<MetricsStatus> {
  // Service key OAuth sessions lack user:profile scope → would 403.
  // API key users (non-subscribers) fall through and use x-api-key auth.
  // This check runs before the disk read so we never persist auth-state-derived
  // answers — only real API responses go to disk. Otherwise a service-key
  // session would poison the cache for a later full-OAuth session.
  if (isClaudeAISubscriber() && !hasProfileScope()) {
    return { enabled: false, hasError: false }
  }

  const cached = getGlobalConfig().metricsStatusCache
  if (cached) {
    if (Date.now() - cached.timestamp > DISK_CACHE_TTL_MS) {
      // saveGlobalConfig's fallback path (config.ts:731) can throw if both
      // locked and fallback writes fail — catch here so fire-and-forget
      // doesn't become an unhandled rejection.
      void refreshMetricsStatus().catch(logError)
    }
    return {
      enabled: cached.enabled,
      hasError: false,
    }
  }

  // First-ever run on this machine: block on the network to populate disk.
  return refreshMetricsStatus()
}

// Export for testing purposes only
export const _clearMetricsEnabledCacheForTesting = (): void => {
  memoizedCheckMetrics.cache.clear()
}
