import crypto from 'node:crypto'
import { Router } from 'express'
import { config } from '../../config.js'
import { upsertWebsiteProjectByRepo } from '../../services/appwriteAdmin.js'
import {
  fetchPreviewConfig,
  defaultPreviewConfig,
  runDeploy,
  buildPreviewUrl,
} from '../../services/previewDeploy.js'
import { createGitPushWorksheet } from '../../services/gitWorksheet.js'

const router = Router()

function verifyWebhookToken(req) {
  const token = config.gitea.webhookToken
  if (!token) return false
  const queryToken = req.query.token
  const headerToken = req.get('X-Gitea-Token')
  if (queryToken === token || headerToken === token) return true

  // Gitea sendet das Webhook-Secret nicht im Klartext, sondern als
  // HMAC-SHA256-Signatur des Request-Bodys (X-Gitea-Signature).
  const signature = req.get('X-Gitea-Signature') || req.get('X-Gogs-Signature')
  if (signature && req.rawBody) {
    const expected = crypto.createHmac('sha256', token).update(req.rawBody).digest('hex')
    try {
      return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected))
    } catch {
      return false
    }
  }
  return false
}

router.post('/gitea', async (req, res) => {
  if (!verifyWebhookToken(req)) {
    return res.status(401).json({ error: 'Unauthorized' })
  }

  const payload = req.body || {}
  const ref = payload.ref || ''
  const repo = payload.repository || {}
  const repoFullName = repo.full_name || ''
  const commits = payload.commits || []
  const pusher = payload.pusher || {}
  const commitSha = payload.after || commits[commits.length - 1]?.id || ''

  if (!repoFullName) {
    return res.status(400).json({ error: 'repository.full_name fehlt' })
  }

  const branch = ref.replace('refs/heads/', '') || 'main'

  try {
    const previewConfigFile = await fetchPreviewConfig(repoFullName, branch)
    const previewConfig = previewConfigFile || defaultPreviewConfig(repoFullName)
    const hasPreview = Boolean(previewConfigFile?.enabled !== false && previewConfigFile)
    const subdomain = previewConfig.subdomain || repoFullName.split('/').pop()
    const previewUrl = subdomain ? buildPreviewUrl(subdomain) : ''

    let deployResult = { deployed: false, skipped: true }
    const configBranch = previewConfig.branch || 'main'

    if (hasPreview && previewConfig.enabled !== false && branch === configBranch) {
      try {
        deployResult = await runDeploy(repoFullName, branch, previewConfig)
      } catch (deployErr) {
        console.error('[webhook] deploy failed:', deployErr.message)
        deployResult = { deployed: false, error: deployErr.message }
      }
    }

    const projectPayload = {
      projectName: previewConfig.displayName || repo.name || subdomain,
      templateName: previewConfig.templateName || config.gitea.templateRepo,
      giteaRepoUrl: repo.html_url || `${config.gitea.baseUrl}/${repoFullName}`,
      giteaRepoName: repo.name || subdomain,
      repoFullName,
    }

    if (subdomain) projectPayload.subdomain = subdomain
    if (previewUrl) projectPayload.previewUrl = previewUrl

    if (deployResult.deployed) {
      projectPayload.status = 'deployed'
      projectPayload.provisioningStatus = 'ready'
    } else if (hasPreview) {
      projectPayload.status = 'pending'
      projectPayload.provisioningStatus = deployResult.error ? 'deploy_failed' : 'pending'
    } else {
      projectPayload.status = 'synced'
    }

    const project = await upsertWebsiteProjectByRepo(repoFullName, projectPayload)

    let gitWorksheet = null
    if (project.ticketId && commitSha && commitSha !== '0000000000000000000000000000000000000000') {
      gitWorksheet = await createGitPushWorksheet({
        ticketId: project.ticketId,
        repoFullName,
        branch,
        commits,
        pusher,
        commitSha,
      })
    }

    return res.json({
      ok: true,
      repoFullName,
      subdomain,
      previewUrl,
      deploy: deployResult,
      projectId: project.$id,
      gitWorksheet,
    })
  } catch (err) {
    console.error('[webhook]', err)
    return res.status(500).json({ error: err.message || 'Webhook-Verarbeitung fehlgeschlagen' })
  }
})

export default router