import { defineStore } from 'pinia'
import { ref, computed } from 'vue'
import * as api from '../api/client.js'

/**
 * Session-storage key for last visited folder per connection.
 * Only folder navigation state is stored — never tokens or credentials.
 */
function folderSessionKey(connectionId) {
  return `docuvault:cloud:folder:${connectionId}`
}

/**
 * Valid health state values used by both browser compact status and Settings diagnostics.
 * Translates server vocabulary to UI-actionable states (D-12).
 *
 * healthy          — provider reachable and credentials valid
 * requires_reauth  — credentials expired or revoked; reconnect required (D-14/D-15)
 * degraded         — transient outage; credentials preserved, retry/reconnect allowed (D-15)
 * unknown          — not yet tested or health state unavailable
 */
const VALID_HEALTH_STATES = new Set(['healthy', 'requires_reauth', 'degraded', 'unknown'])

export function saveLastFolder(connectionId, folderId) {
  try {
    if (folderId && folderId !== 'root') {
      sessionStorage.setItem(folderSessionKey(connectionId), folderId)
    } else {
      sessionStorage.removeItem(folderSessionKey(connectionId))
    }
  } catch {
    // sessionStorage unavailable — ignore
  }
}

export function loadLastFolder(connectionId) {
  try {
    return sessionStorage.getItem(folderSessionKey(connectionId)) || null
  } catch {
    return null
  }
}

// ── Phase 14: Analysis status translation ────────────────────────────────────

/**
 * D-06: Single source for internal status → simplified UI label mapping.
 * Components never translate independently — they call translateAnalysisStatus.
 */
const SIMPLIFIED_STATUS_MAP = {
  queued: 'waiting',
  downloading: 'working',
  extracting: 'working',
  classifying: 'working',
  indexed: 'done',
  already_current: 'done',
  cancelled: 'skipped',
  failed: 'failed',
  unsupported: 'skipped',
  stale: 'working',
}

const DETAILED_STATUS_MAP = {
  queued: 'queued',
  downloading: 'downloading',
  extracting: 'extracting',
  classifying: 'classifying',
  indexed: 'indexed',
  already_current: 'indexed',
  cancelled: 'cancelled',
  failed: 'failed',
  unsupported: 'unsupported',
  stale: 'stale',
}

export const useCloudConnectionsStore = defineStore('cloudConnections', () => {
  const connections = ref([])
  const loading = ref(false)
  const error = ref(null)

  // Active browse state (populated by CloudFolderView)
  const selectedConnectionId = ref(null)
  const browseItems = ref([])
  const browseLoading = ref(false)
  const browseError = ref(null)
  /** Capabilities for the currently selected connection */
  const capabilities = ref(null)
  /** 'refreshing' | 'fresh' | 'stale' | null */
  const folderFreshness = ref(null)
  const lastRefreshedAt = ref(null)
  /** 'cached' | 'cloud_only' | null */
  const byteAvailability = ref(null)

  // ── Phase 14: Analysis state ─────────────────────────────────────────────────

  /**
   * Active analysis job for the current connection session.
   * Stored in Pinia memory only — never persisted to localStorage/sessionStorage.
   * T-14-02: No credentials or object_key fields stored here.
   */
  const activeAnalysisJob = ref(null)

  /**
   * Analysis queue items from the active job for display in StorageBrowser.
   * Derived from activeAnalysisJob.items when a job is active.
   */
  const analysisQueue = computed(() => {
    if (!activeAnalysisJob.value) return []
    const items = activeAnalysisJob.value.items ?? []
    return items.map(item => ({
      job_id: activeAnalysisJob.value.job_id,
      item_id: item.item_id,
      name: item.name,
      status: item.status,
      ui_status: SIMPLIFIED_STATUS_MAP[item.status] ?? item.status,
      progress: item.progress ?? 0,
      error: item.error ?? null,
    }))
  })

  /**
   * D-11: Failure behavior for analysis jobs.
   * 'pause_batch' — pause the whole batch on any item failure (default)
   * 'continue_item' — skip failed items and continue
   */
  const failureBehavior = ref('pause_batch')

  /**
   * D-06: When true, per-item status shows detailed internal stages
   * (downloading/extracting/classifying). When false (default), shows simplified
   * labels (waiting/working/done/skipped/failed).
   */
  const detailedAnalysisProgress = ref(false)

  /**
   * CACHE-04: User-configured cloud cache limit in bytes.
   * Default: 500 MB (500 * 1024 * 1024).
   * Hydrated from server via loadCacheSettings — in-memory only, not persisted.
   */
  const cacheLimit = ref(500 * 1024 * 1024)

  /**
   * Server-authoritative tier cap for the cache limit in bytes.
   * Loaded from GET /api/cloud/analysis/cache (tier_cap_bytes field).
   * null until loadCacheSettings has run.
   */
  const tierCapBytes = ref(null)

  /**
   * Current aggregate cache usage from the server.
   * Loaded from GET /api/cloud/analysis/cache.
   * { entry_count: number, total_bytes: number } — no object_key or credentials.
   */
  const cacheUsage = ref(null)

  /**
   * Whether the last loadCacheSettings call is in flight.
   */
  const cacheSettingsLoading = ref(false)

  /**
   * Validation/network error from the last settings call, or null.
   */
  const cacheSettingsError = ref(null)

  /**
   * D-12: Connection health state map — single source for both browser compact status
   * and Settings full diagnostics.
   *
   * Key: connection UUID
   * Value: { state: 'healthy'|'requires_reauth'|'degraded'|'unknown', error_code, error_message, checked_at }
   *
   * Neither the browser nor Settings translate server states independently —
   * they read from this map only.
   */
  const connectionHealth = ref({})

  /**
   * D-13 / D-14: Set of connection IDs that need a health retest.
   * CloudFolderView reads this and performs the test after navigation settles.
   * Cleared after the test is performed.
   */
  const pendingHealthRetest = ref(new Set())

  /**
   * D-14: Flag set during reconnect so CloudFolderView refreshes the current folder
   * after a successful reconnect without clearing cached browse items first.
   */
  const reconnectRefreshPending = ref(false)

  const selectedConnection = computed(() =>
    connections.value.find(c => c.id === selectedConnectionId.value) ?? null
  )

  async function fetchConnections() {
    loading.value = true
    error.value = null
    try {
      const data = await api.listCloudConnections()
      connections.value = data.items ?? []
    } catch (e) {
      error.value = e.message || 'Failed to load cloud connections'
    } finally {
      loading.value = false
    }
  }

  async function disconnect(id) {
    try {
      await api.disconnectCloud(id)
      connections.value = connections.value.filter(c => c.id !== id)
      if (selectedConnectionId.value === id) {
        selectedConnectionId.value = null
      }
    } catch (e) {
      throw e
    }
  }

  async function disconnectAll() {
    const ids = connections.value.map(c => c.id)
    for (const id of ids) await disconnect(id)
    connections.value = []
  }

  /**
   * Rename a connection's display_name via the API.
   * Only updates the single returned connection in state.
   */
  async function rename(id, displayName) {
    const trimmed = displayName?.trim()
    if (!trimmed) throw new Error('Display name cannot be empty')
    const updated = await api.renameCloudConnection(id, trimmed)
    const idx = connections.value.findIndex(c => c.id === id)
    if (idx !== -1) {
      connections.value[idx] = { ...connections.value[idx], ...updated }
    }
    return updated
  }

  /**
   * Default display_name for a connection.
   * If another connection shares the same provider, append a 4-char UUID suffix.
   */
  function defaultDisplayName(connection) {
    const providerLabel = {
      google_drive: 'Google Drive',
      onedrive: 'OneDrive',
      nextcloud: 'Nextcloud',
      webdav: 'WebDAV',
    }[connection.provider] ?? connection.provider
    const siblings = connections.value.filter(
      c => c.provider === connection.provider && c.id !== connection.id
    )
    if (siblings.length > 0) {
      return `${providerLabel} (${connection.id.slice(0, 4)})`
    }
    return providerLabel
  }

  function selectConnection(id) {
    selectedConnectionId.value = id
    browseItems.value = []
    browseError.value = null
    capabilities.value = null
    folderFreshness.value = null
    lastRefreshedAt.value = null
    byteAvailability.value = null
  }

  function setBrowseState({ items, caps, freshness, refreshedAt, byteAvail, err }) {
    if (err !== undefined) browseError.value = err
    if (items !== undefined) browseItems.value = items
    if (caps !== undefined) capabilities.value = caps
    if (freshness !== undefined) folderFreshness.value = freshness
    if (refreshedAt !== undefined) lastRefreshedAt.value = refreshedAt
    if (byteAvail !== undefined) byteAvailability.value = byteAvail
  }

  /**
   * D-12: Set the health state for a specific connection.
   * Translates server health payload to the UI-actionable vocabulary.
   * Both browser compact status and Settings diagnostics consume this.
   *
   * @param {string} id — connection UUID
   * @param {{ state: string, error_code?: string, error_message?: string, checked_at?: string }} healthData
   */
  function setConnectionHealth(id, healthData) {
    const state = VALID_HEALTH_STATES.has(healthData?.state) ? healthData.state : 'unknown'
    connectionHealth.value = {
      ...connectionHealth.value,
      [id]: {
        state,
        error_code: healthData?.error_code ?? null,
        error_message: healthData?.error_message ?? null,
        checked_at: healthData?.checked_at ?? null,
      },
    }
  }

  /**
   * D-13: Mark a connection as requiring a health retest after a credential failure.
   * This is the complement of the no-probe-on-navigation rule:
   * probes happen only after failures (here), not on ordinary navigation.
   *
   * @param {string} id — connection UUID
   * @param {{ state: string, error_code?: string }} failureData
   */
  function handleHealthFailure(id, failureData) {
    // Record the failure state in the health map
    setConnectionHealth(id, failureData)
    // Schedule a retest (D-13: auto-test after credential failure)
    pendingHealthRetest.value = new Set([...pendingHealthRetest.value, id])
  }

  /**
   * D-14: Mark that a reconnect just completed and the current folder should refresh.
   * Does NOT clear browse items — they stay visible as stale while the refresh runs.
   *
   * @param {string} id — connection UUID
   */
  function markReconnectRefreshPending(id) {
    reconnectRefreshPending.value = true
    // Keep browse items visible but downgrade freshness to stale (D-14)
    if (folderFreshness.value !== null) {
      folderFreshness.value = 'stale'
    }
  }

  /**
   * D-14: Enter reconnecting state — preserve cached items as stale.
   * Does NOT call selectConnection (which clears items).
   *
   * @param {string} id — connection UUID
   */
  function markReconnecting(id) {
    // D-14: cached metadata remains visible; downgrade freshness only
    if (folderFreshness.value !== null) {
      folderFreshness.value = 'stale'
    }
    // Set health to unknown while reconnect is in flight
    connectionHealth.value = {
      ...connectionHealth.value,
      [id]: { state: 'unknown', error_code: null, error_message: null, checked_at: null },
    }
  }

  /**
   * D-13: Explicitly test the health of a connection.
   * Only called after connect/reconnect/failure — never as a navigation side effect.
   *
   * @param {string} id — connection UUID
   * @returns {Promise<{ state: string }>}
   */
  async function testConnection(id) {
    try {
      const result = await api.testCloudConnection(id)
      // WR-06: server returns { status: ... }, not { state: ... }. Translate at the
      // store boundary — internal vocabulary uses `state` but the API field is `status`.
      const state = result?.status ?? 'unknown'
      setConnectionHealth(id, { state, ...result })
      // Clear pending retest flag for this connection
      const next = new Set(pendingHealthRetest.value)
      next.delete(id)
      pendingHealthRetest.value = next
      return result
    } catch (e) {
      const failState = { state: 'degraded', error_code: 'probe_error', error_message: e?.message ?? 'Health check failed' }
      setConnectionHealth(id, failState)
      return failState
    }
  }

  /**
   * D-13: Store-level reconnect handler.
   * Marks reconnecting state (cached items preserved), then fetches updated connections.
   *
   * @param {string} id — connection UUID
   */
  async function reconnect(id) {
    markReconnecting(id)
    // Re-fetch connection list to pick up updated status
    await fetchConnections()
    markReconnectRefreshPending(id)
  }

  /**
   * D-12 / D-13: Connections with null or absent health are candidates for an initial test.
   * The store exposes this as a computed so the view can decide when to run tests.
   */
  const connectionsNeedingHealthCheck = computed(() =>
    connections.value.filter(c => {
      const h = connectionHealth.value[c.id]
      return !h || h.state === undefined || h.state === 'unknown'
    })
  )

  /**
   * D-12: Retrieve the health state for a specific connection.
   * Returns { state: 'unknown', ... } if no health data is available.
   *
   * @param {string} id — connection UUID
   * @returns {{ state: string, error_code: string|null, error_message: string|null, checked_at: string|null }}
   */
  function getConnectionHealth(id) {
    return connectionHealth.value[id] ?? { state: 'unknown', error_code: null, error_message: null, checked_at: null }
  }

  // ── Phase 14: Analysis actions ─────────────────────────────────────────────

  /**
   * D-06: Translate an internal analysis status to a UI label.
   * Single translation source — components must not translate independently.
   *
   * @param {string} status - Internal status (queued, downloading, extracting, etc.)
   * @param {{ detailed?: boolean }} [opts]
   * @returns {string} - UI label
   */
  function translateAnalysisStatus(status, opts = {}) {
    const map = opts.detailed ? DETAILED_STATUS_MAP : SIMPLIFIED_STATUS_MAP
    return map[status] ?? status
  }

  /**
   * ANALYZE-01 / ANALYZE-03: Request a scope estimate for an analysis job.
   * No provider bytes are downloaded (T-14-04).
   *
   * @param {string} connectionId - Connection UUID
   * @param {{ scope: string, provider_item_ids?: string[], recursive?: boolean }} params
   * @returns {Promise<object>} AnalysisEstimateOut
   */
  async function requestEstimate(connectionId, params) {
    return api.estimateAnalysis(connectionId, params)
  }

  /**
   * ANALYZE-01: Enqueue an analysis job and track it in store state.
   *
   * @param {string} connectionId - Connection UUID
   * @param {{ scope: string, provider_item_ids?: string[], recursive?: boolean,
   *            failure_behavior?: string }} params
   * @returns {Promise<object>} AnalysisEnqueueOut
   */
  async function enqueueAnalysis(connectionId, params) {
    const result = await api.enqueueAnalysis(connectionId, {
      ...params,
      failure_behavior: params.failure_behavior ?? failureBehavior.value,
    })
    // Initialize the active job in memory (no credentials stored)
    activeAnalysisJob.value = {
      job_id: result.job_id,
      connection_id: connectionId,
      status: result.status,
      total_count: result.total_count,
      queued_count: result.queued_count,
      already_current_count: result.already_current_count,
      unsupported_count: result.unsupported_count,
      items: [],
    }
    return result
  }

  /**
   * ANALYZE-04: Fetch and update status of the active analysis job.
   * T-14-02: Response must never include credentials or object_key.
   *
   * @param {string} jobId - Job UUID
   * @returns {Promise<object>} AnalysisJobOut
   */
  async function fetchJobStatus(jobId) {
    const result = await api.getAnalysisJobStatus(jobId)
    // Store job state in Pinia memory — no credentials/object_key fields exposed
    activeAnalysisJob.value = {
      job_id: result.job_id ?? jobId,
      connection_id: result.connection_id ?? activeAnalysisJob.value?.connection_id,
      status: result.status,
      total_count: result.total_count ?? 0,
      queued_count: result.queued_count ?? 0,
      already_current_count: result.already_current_count ?? 0,
      unsupported_count: result.unsupported_count ?? 0,
      items: (result.items ?? []).map(item => ({
        item_id: item.item_id,
        cloud_item_id: item.cloud_item_id,
        name: item.name,
        status: item.status,
        error: item.error ?? null,
      })),
    }
    return result
  }

  /**
   * ANALYZE-05: Cancel the entire analysis job batch.
   *
   * @param {string} jobId - Job UUID
   */
  async function cancelJob(jobId) {
    const result = await api.cancelAnalysisJob(jobId)
    if (activeAnalysisJob.value?.job_id === jobId) {
      activeAnalysisJob.value = { ...activeAnalysisJob.value, status: 'cancelled' }
    }
    return result
  }

  /**
   * ANALYZE-05: Retry a failed analysis job item.
   *
   * @param {string} jobId - Job UUID
   * @param {string} itemId - Item UUID
   */
  async function retryItem(jobId, itemId) {
    return api.retryAnalysisItem(jobId, itemId)
  }

  /**
   * ANALYZE-05: Skip a queued or failed analysis job item.
   *
   * @param {string} jobId - Job UUID
   * @param {string} itemId - Item UUID
   */
  async function skipItem(jobId, itemId) {
    return api.skipAnalysisItem(jobId, itemId)
  }

  /**
   * ANALYZE-05: Cancel a single analysis job item.
   *
   * @param {string} jobId - Job UUID
   * @param {string} itemId - Item UUID
   */
  async function cancelItem(jobId, itemId) {
    return api.cancelAnalysisItem(jobId, itemId)
  }

  /**
   * D-11: Set the failure behavior for analysis jobs.
   *
   * @param {'pause_batch'|'continue_item'} behavior
   */
  function setFailureBehavior(behavior) {
    failureBehavior.value = behavior
  }

  /**
   * D-06: Toggle detailed analysis progress mode.
   *
   * @param {boolean} enabled
   */
  function setDetailedAnalysisProgress(enabled) {
    detailedAnalysisProgress.value = !!enabled
  }

  /**
   * CACHE-04: Load cache status and analysis settings from the server.
   *
   * Hydrates cacheLimit, tierCapBytes, cacheUsage, detailedAnalysisProgress,
   * and failureBehavior from the authoritative backend state.
   *
   * Errors do not clear existing in-memory settings — cacheSettingsError is
   * set so the UI can surface a controlled message.
   */
  async function loadCacheSettings() {
    cacheSettingsLoading.value = true
    cacheSettingsError.value = null
    try {
      const result = await api.getCacheSettings()
      // Hydrate server-authoritative values into local state
      if (result?.cache_limit_bytes !== undefined) {
        cacheLimit.value = result.cache_limit_bytes
      }
      if (result?.tier_cap_bytes !== undefined) {
        tierCapBytes.value = result.tier_cap_bytes
      }
      if (result?.entry_count !== undefined || result?.total_bytes !== undefined) {
        cacheUsage.value = {
          entry_count: result.entry_count ?? 0,
          total_bytes: result.total_bytes ?? 0,
        }
      }
      if (result?.analysis_progress_detail !== undefined) {
        detailedAnalysisProgress.value = !!result.analysis_progress_detail
      }
      if (result?.analysis_failure_behavior !== undefined) {
        failureBehavior.value = result.analysis_failure_behavior
      }
      return result
    } catch (e) {
      // Do not clear existing settings on error — surface a controlled message
      cacheSettingsError.value = e?.message ?? 'Failed to load cache settings'
      return null
    } finally {
      cacheSettingsLoading.value = false
    }
  }

  /**
   * CACHE-04: Update user cache settings via the API.
   *
   * Merges server response back into local state after a successful update.
   * Validation errors surface as a thrown error (caller responsible for display).
   *
   * @param {{ cloud_cache_limit_bytes?: number, analysis_progress_detail?: boolean,
   *            analysis_failure_behavior?: string }} params
   */
  async function updateCacheSettings(params) {
    cacheSettingsError.value = null
    try {
      const result = await api.updateCacheSettings(params)
      // Merge server response into local state
      if (result?.cache_limit_bytes !== undefined) {
        cacheLimit.value = result.cache_limit_bytes
      }
      if (result?.cloud_cache_limit_bytes !== undefined) {
        cacheLimit.value = result.cloud_cache_limit_bytes
      }
      if (result?.tier_cap_bytes !== undefined) {
        tierCapBytes.value = result.tier_cap_bytes
      }
      if (result?.entry_count !== undefined || result?.total_bytes !== undefined) {
        cacheUsage.value = {
          entry_count: result.entry_count ?? 0,
          total_bytes: result.total_bytes ?? 0,
        }
      }
      if (result?.analysis_progress_detail !== undefined) {
        detailedAnalysisProgress.value = !!result.analysis_progress_detail
      }
      if (result?.analysis_failure_behavior !== undefined) {
        failureBehavior.value = result.analysis_failure_behavior
      }
      return result
    } catch (e) {
      // Surface validation error without clearing existing settings
      cacheSettingsError.value = e?.message ?? 'Failed to update cache settings'
      throw e
    }
  }

  return {
    connections,
    loading,
    error,
    selectedConnectionId,
    selectedConnection,
    browseItems,
    browseLoading,
    browseError,
    capabilities,
    folderFreshness,
    lastRefreshedAt,
    byteAvailability,
    // D-12: health state map — single source for browser and Settings
    connectionHealth,
    // D-13: pending health retests (after credential failures)
    pendingHealthRetest,
    // D-14: reconnect refresh flag
    reconnectRefreshPending,
    // D-12: connections needing initial health check
    connectionsNeedingHealthCheck,
    fetchConnections,
    disconnect,
    disconnectAll,
    rename,
    defaultDisplayName,
    selectConnection,
    setBrowseState,
    // D-12/D-13: health management
    setConnectionHealth,
    getConnectionHealth,
    handleHealthFailure,
    markReconnectRefreshPending,
    markReconnecting,
    testConnection,
    reconnect,
    // ── Phase 14: Analysis state and actions ──────────────────────────────────
    // State (Pinia memory only — no credentials stored)
    activeAnalysisJob,
    analysisQueue,
    failureBehavior,
    detailedAnalysisProgress,
    cacheLimit,
    // D-06: single status translation source
    translateAnalysisStatus,
    // Analysis job lifecycle
    requestEstimate,
    enqueueAnalysis,
    fetchJobStatus,
    cancelJob,
    retryItem,
    skipItem,
    cancelItem,
    // User preferences and cache settings
    setFailureBehavior,
    setDetailedAnalysisProgress,
    loadCacheSettings,
    updateCacheSettings,
    // Server-authoritative cache state
    tierCapBytes,
    cacheUsage,
    cacheSettingsLoading,
    cacheSettingsError,
  }
})