import { WORKFLOW_ACTIVE_STATUSES } from '../../consts'
import * as SyncQueue from '../../sync-queue'
import { randomUUID } from '../../utils/crypto'
import { enumerateFilesInFolder } from '../../utils/enumerate-files'
import { getAliasedName } from '../../utils/get-aliased-name'
import type * as bp from '.botpress'

type ScheduledSyncProps = bp.EventHandlerProps

type FolderConfig = {
  syncNewFiles?: boolean
  path?: string
  integrationInstanceAlias?: string
  integrationDefinitionName?: string
  transferFileToBotpressAlias?: string
}

type FolderSyncSettings = Record<string, Record<string, FolderConfig>>

type IntegrationGroup = {
  integrationInstanceAlias: string
  integrationDefinitionName: string
  transferFileToBotpressAlias: string
  folders: Array<{ folderId: string; path: string; kbId: string }>
}

export const handleEvent = async (props: ScheduledSyncProps) => {
  const { logger, ctx } = props

  if ((props.configuration?.scheduledSyncIntervalHours ?? 0) <= 0) {
    logger.debug('Scheduled sync disabled (interval is 0)')
    return
  }

  const shouldSync = await _hasEnoughTimeElapsed(props, props.configuration?.scheduledSyncIntervalHours ?? 0)
  if (!shouldSync) {
    logger.debug('Scheduled sync skipped: not enough time elapsed since last sync')
    return
  }

  const settings = await _getFolderSyncSettings(props)
  if (!settings) {
    logger.debug('Scheduled sync skipped: no folder sync settings found')
    return
  }

  const integrationGroups = _groupFoldersByIntegration(settings, logger)
  if (integrationGroups.length === 0) {
    logger.debug('Scheduled sync skipped: no folders with integration info configured')
    return
  }

  logger.info(`Scheduled sync starting for ${integrationGroups.length} integration(s)`)

  // Set lastSyncAt immediately to prevent concurrent cron invocations from
  // starting a duplicate sync while this one is still running.
  const syncStartedAt = new Date().toISOString()
  await props.states.bot.lastScheduledSync.set(ctx.botId, {
    lastSyncAt: syncStartedAt,
  })

  let hasSucceeded = false
  try {
    for (const group of integrationGroups) {
      try {
        await _syncIntegrationGroup(props, group)
        hasSucceeded = true
      } catch (error) {
        logger.error(
          `Scheduled sync failed for integration "${group.integrationInstanceAlias}": ${error instanceof Error ? error.message : String(error)}`
        )
      }
    }
  } finally {
    if (!hasSucceeded) {
      // Reset lastSyncAt so the next cron trigger retries immediately
      await props.states.bot.lastScheduledSync.set(ctx.botId, {
        lastSyncAt: undefined,
      })
      logger.warn('Scheduled sync: all integration groups failed, will retry on next trigger')
    }
  }
}

const _hasEnoughTimeElapsed = async (props: ScheduledSyncProps, intervalHours: number): Promise<boolean> => {
  try {
    const { lastSyncAt } = await props.states.bot.lastScheduledSync.get(props.ctx.botId)
    if (!lastSyncAt) {
      return true
    }
    const elapsed = Date.now() - new Date(lastSyncAt).getTime()
    return elapsed >= intervalHours * 60 * 60 * 1000
  } catch {
    return true
  }
}

const _getFolderSyncSettings = async (props: ScheduledSyncProps) => {
  try {
    const state = await props.states.bot.folderSyncSettings.get(props.ctx.botId)
    return state?.settings
  } catch {
    return null
  }
}

const _groupFoldersByIntegration = (
  settings: FolderSyncSettings,
  logger?: { warn: (...args: unknown[]) => void }
): IntegrationGroup[] => {
  const groupMap = new Map<string, IntegrationGroup>()

  for (const [kbId, folders] of Object.entries(settings)) {
    for (const [folderId, config] of Object.entries(folders)) {
      if (!config.integrationInstanceAlias || !config.integrationDefinitionName) {
        continue
      }

      const alias = config.integrationInstanceAlias
      let group = groupMap.get(alias)
      if (!group) {
        group = {
          integrationInstanceAlias: alias,
          integrationDefinitionName: config.integrationDefinitionName,
          transferFileToBotpressAlias: config.transferFileToBotpressAlias ?? 'filesReadonlyTransferFileToBotpress',
          folders: [],
        }
        groupMap.set(alias, group)
      }

      const configuredAlias = config.transferFileToBotpressAlias ?? 'filesReadonlyTransferFileToBotpress'
      if (configuredAlias !== group.transferFileToBotpressAlias) {
        logger?.warn(
          `Integration "${alias}" has conflicting transferFileToBotpressAlias values: ` +
            `"${group.transferFileToBotpressAlias}" (used) vs "${configuredAlias}" (ignored, from KB "${kbId}")`
        )
      }

      group.folders.push({
        folderId,
        path: config.path ?? '/',
        kbId,
      })
    }
  }

  return Array.from(groupMap.values())
}

const _syncIntegrationGroup = async (props: ScheduledSyncProps, group: IntegrationGroup) => {
  const { logger } = props

  const isBusy = await _isSyncInProgress(props, group.integrationInstanceAlias)
  if (isBusy) {
    logger.info(`Scheduled sync skipped for "${group.integrationInstanceAlias}": sync already in progress`)
    return
  }

  const allFiles: Array<{
    id: string
    name: string
    absolutePath: string
    sizeInBytes?: number
    contentHash?: string
    kbId: string
  }> = []

  for (const folder of group.folders) {
    try {
      const files = await enumerateFilesInFolder({
        listItemsInFolder: (input) =>
          props.client
            .callAction({
              type: `${group.integrationInstanceAlias}:filesReadonlyListItemsInFolder`,
              input,
            })
            .then((r) => r.output),
        folderId: folder.folderId,
        folderPath: folder.path,
        logger,
      })

      for (const file of files) {
        allFiles.push({ ...file, kbId: folder.kbId })
      }
    } catch (error) {
      logger.error(
        `Failed to enumerate files in folder "${folder.path}" (${folder.folderId}): ${error instanceof Error ? error.message : String(error)}`
      )
    }
  }

  if (allFiles.length === 0) {
    logger.info(`Scheduled sync: no files found for integration "${group.integrationInstanceAlias}"`)
    return
  }

  // Group files by kbId to create separate sync jobs per knowledge base
  const filesByKb = new Map<string, typeof allFiles>()
  for (const file of allFiles) {
    const existing = filesByKb.get(file.kbId) ?? []
    existing.push(file)
    filesByKb.set(file.kbId, existing)
  }

  for (const [kbId, files] of filesByKb) {
    const syncJobId = await randomUUID()
    const fileKey = `${getAliasedName('knowledge-connector', props.alias)}:${group.integrationInstanceAlias}:/${syncJobId}.jsonl`
    const syncInitiatedAt = new Date().toISOString()

    logger.info(
      `Scheduled sync: starting job for "${group.integrationInstanceAlias}" KB "${kbId}" with ${files.length} files`,
      { syncJobId }
    )

    let jobFileId: string | undefined
    try {
      jobFileId = await SyncQueue.jobFileManager.updateSyncQueue(
        props,
        fileKey,
        files.map((file) => ({
          id: file.id,
          name: file.name,
          absolutePath: file.absolutePath,
          type: 'file' as const,
          status: 'pending' as const,
          sizeInBytes: file.sizeInBytes,
          contentHash: file.contentHash,
          addToKbId: kbId,
        })),
        {
          syncJobId,
          integrationName: group.integrationDefinitionName,
          integrationInstanceAlias: group.integrationInstanceAlias,
          syncInitiatedAt,
        }
      )

      await props.workflows.processQueue.startNewInstance({
        input: {
          jobFileId,
          transferFileToBotpressAlias: group.transferFileToBotpressAlias,
        },
        tags: {
          integrationDefinitionName: group.integrationDefinitionName,
          integrationInstanceAlias: group.integrationInstanceAlias,
          syncJobId,
          syncInitiatedAt,
        },
      })
    } catch (error) {
      if (jobFileId) {
        await props.client.deleteFile({ id: jobFileId }).catch(() => {})
      }
      throw error
    }
  }
}

const _isSyncInProgress = async (props: ScheduledSyncProps, integrationInstanceAlias: string): Promise<boolean> => {
  const workflowsInProgress = await props.workflows.processQueue
    .listInstances({
      statuses: [...WORKFLOW_ACTIVE_STATUSES],
      tags: { integrationInstanceAlias },
    })
    .take(1)

  return workflowsInProgress.length > 0
}