import { createLogger } from '@sim/logger'
import { getErrorMessage, toError } from '@sim/utils/errors'
import { type NextRequest, NextResponse } from 'next/server'
import { vantaUploadContract } from '@/lib/api/contracts/tools/vanta'
import { parseRequest } from '@/lib/api/server'
import { checkInternalAuth } from '@/lib/auth/hybrid'
import { generateRequestId } from '@/lib/core/utils/request'
import { withRouteHandler } from '@/lib/core/utils/with-route-handler'
import { processFilesToUserFiles, type RawFileInput } from '@/lib/uploads/utils/file-utils'
import { downloadServableFileFromStorage } from '@/lib/uploads/utils/file-utils.server'
import { docNotReadyResponse } from '@/lib/uploads/utils/servable-file-response'
import { assertToolFileAccess } from '@/app/api/files/authorization'
import {
  asVantaRecord,
  buildVantaUrl,
  extractVantaError,
  fetchVantaWithAuth,
  getVantaBaseUrl,
  normalizeVantaUploadedFile,
  VANTA_DOCUMENT_UPLOAD_SCOPE,
} from '@/tools/vanta/utils'

export const dynamic = 'force-dynamic'

const logger = createLogger('VantaUploadAPI')

const MAX_UPLOAD_SIZE_BYTES = 100 * 1024 * 1024

function uploadSizeError(bytes: number): NextResponse {
  const sizeMB = (bytes / (1024 * 1024)).toFixed(2)
  return NextResponse.json(
    { success: false, error: `File size (${sizeMB}MB) exceeds upload limit of 100MB` },
    { status: 400 }
  )
}

export const POST = withRouteHandler(async (request: NextRequest) => {
  const requestId = generateRequestId()

  try {
    const authResult = await checkInternalAuth(request, { requireWorkflowId: false })
    if (!authResult.success || !authResult.userId) {
      logger.warn(`[${requestId}] Unauthorized Vanta upload attempt`, {
        error: authResult.error || 'Missing userId',
      })
      return NextResponse.json(
        { success: false, error: authResult.error || 'Unauthorized' },
        { status: 401 }
      )
    }

    const parsed = await parseRequest(vantaUploadContract, request, {})
    if (!parsed.success) return parsed.response
    const params = parsed.data.body

    let fileBuffer: Buffer
    let fileName: string
    let mimeType: string

    if (params.file) {
      const userFiles = processFilesToUserFiles([params.file as RawFileInput], requestId, logger)
      if (userFiles.length === 0) {
        return NextResponse.json({ success: false, error: 'Invalid file input' }, { status: 400 })
      }

      const userFile = userFiles[0]
      const denied = await assertToolFileAccess(userFile.key, authResult.userId, requestId, logger)
      if (denied) return denied

      if (userFile.size > MAX_UPLOAD_SIZE_BYTES) {
        return uploadSizeError(userFile.size)
      }

      try {
        const resolved = await downloadServableFileFromStorage(userFile, requestId, logger)
        fileBuffer = resolved.buffer
        fileName = params.fileName || userFile.name
        mimeType =
          resolved.contentType || userFile.type || params.mimeType || 'application/octet-stream'
      } catch (error) {
        const notReady = docNotReadyResponse(error)
        if (notReady) return notReady
        logger.error(`[${requestId}] Failed to download Vanta upload file`, {
          error: getErrorMessage(error),
        })
        return NextResponse.json(
          { success: false, error: getErrorMessage(error, 'Failed to download file') },
          { status: 500 }
        )
      }
    } else if (params.fileContent) {
      fileBuffer = Buffer.from(params.fileContent, 'base64')
      fileName = params.fileName || 'file'
      mimeType = params.mimeType || 'application/octet-stream'
    } else {
      return NextResponse.json({ success: false, error: 'File is required' }, { status: 400 })
    }

    if (fileBuffer.length > MAX_UPLOAD_SIZE_BYTES) {
      return uploadSizeError(fileBuffer.length)
    }

    logger.info(`[${requestId}] Uploading file to Vanta document`, {
      documentId: params.documentId,
      fileName,
      size: fileBuffer.length,
    })

    const uploadUrl = buildVantaUrl(
      getVantaBaseUrl(params.region),
      `/documents/${encodeURIComponent(params.documentId)}/uploads`
    )
    const response = await fetchVantaWithAuth(
      {
        clientId: params.clientId,
        clientSecret: params.clientSecret,
        region: params.region,
        scope: VANTA_DOCUMENT_UPLOAD_SCOPE,
      },
      (accessToken) => {
        const formData = new FormData()
        formData.append(
          'file',
          new Blob([new Uint8Array(fileBuffer)], { type: mimeType }),
          fileName
        )
        if (params.description) {
          formData.append('description', params.description)
        }
        if (params.effectiveAtDate) {
          formData.append('effectiveAtDate', params.effectiveAtDate)
        }
        return fetch(uploadUrl, {
          method: 'POST',
          headers: { Authorization: `Bearer ${accessToken}` },
          body: formData,
          cache: 'no-store',
        })
      }
    )

    const data: unknown = await response.json().catch(() => null)
    if (!response.ok) {
      const message = extractVantaError(data, 'Failed to upload file to Vanta document')
      logger.error(`[${requestId}] Vanta upload failed`, { status: response.status, message })
      return NextResponse.json({ success: false, error: message }, { status: response.status })
    }

    logger.info(`[${requestId}] Vanta upload successful`, { documentId: params.documentId })

    return NextResponse.json({
      success: true,
      output: { upload: normalizeVantaUploadedFile(asVantaRecord(data)) },
    })
  } catch (error) {
    const message = toError(error).message
    logger.error(`[${requestId}] Vanta upload failed`, { error: message })
    return NextResponse.json({ success: false, error: message }, { status: 500 })
  }
})