import { config } from '../config.js'
import { upsertWebsiteProjectByRepo, listDocuments, Query } from './appwriteAdmin.js'
import {
  runDeploy,
  buildPreviewUrl,
} from './previewDeploy.js'

function giteaHeaders() {
  if (!config.gitea.apiToken) {
    throw new Error('GITEA_API_TOKEN fehlt in .env')
  }
  return {
    Authorization: `token ${config.gitea.apiToken}`,
    'Content-Type': 'application/json',
  }
}

async function giteaFetch(path, options = {}) {
  const response = await fetch(`${config.gitea.baseUrl}/api/v1${path}`, {
    ...options,
    headers: { ...giteaHeaders(), ...options.headers },
  })

  const text = await response.text()
  let data = null
  if (text) {
    try {
      data = JSON.parse(text)
    } catch {
      data = { message: text }
    }
  }

  if (!response.ok) {
    let message = data?.message || `Gitea ${response.status}`
    if (response.status === 409 && /same name already exists/i.test(message)) {
      message = 'Ein Gitea-Repository mit diesem Namen existiert bereits. Bitte einen anderen Subdomain-/Repo-Namen w�hlen.'
    }
    const error = new Error(message)
    error.status = response.status
    throw error
  }

  return data
}

function slugify(value) {
  return String(value || '')
    .toLowerCase()
    .replace(/[^a-z0-9-]+/g, '-')
    .replace(/^-+|-+$/g, '')
    .slice(0, 100)
}

export async function listAllAccessibleRepos() {
  const repos = []
  const limit = 50
  let page = 1

  while (true) {
    const batch = await giteaFetch(`/repos/search?limit=${limit}&page=${page}`)
    const data = Array.isArray(batch?.data) ? batch.data : Array.isArray(batch) ? batch : []
    if (data.length === 0) break
    repos.push(...data)
    if (data.length < limit) break
    page += 1
  }

  return repos
}

async function resolveSubdomainForSync(repo, existingDoc) {
  if (existingDoc?.subdomain) return existingDoc.subdomain

  const candidate = slugify(repo.name) || slugify(repo.full_name?.split('/').pop())
  if (!candidate) return ''

  const conflict = await listDocuments(config.collections.websiteProjects, [
    Query.equal('subdomain', candidate),
    Query.limit(1),
  ])

  if (!conflict[0] || conflict[0].repoFullName === repo.full_name) {
    return candidate
  }

  const ownerSlug = slugify(repo.full_name?.replace('/', '-'))
  if (!ownerSlug) return ''

  const ownerConflict = await listDocuments(config.collections.websiteProjects, [
    Query.equal('subdomain', ownerSlug),
    Query.limit(1),
  ])

  if (!ownerConflict[0] || ownerConflict[0].repoFullName === repo.full_name) {
    return ownerSlug
  }

  return ''
}

export async function syncReposToAppwrite() {
  const repos = await listAllAccessibleRepos()
  let created = 0
  let updated = 0

  for (const repo of repos) {
    const repoFullName = repo.full_name
    if (!repoFullName) continue

    const existing = await listDocuments(config.collections.websiteProjects, [
      Query.equal('repoFullName', repoFullName),
      Query.limit(1),
    ])

    const branch = repo.default_branch || 'main'
    const subdomain = await resolveSubdomainForSync(repo, existing[0])
    const previewUrl = subdomain ? buildPreviewUrl(subdomain) : ''

    const payload = {
      projectName: repo.description || repo.name || repoFullName.split('/').pop(),
      giteaRepoUrl: repo.html_url || `${config.gitea.baseUrl}/${repoFullName}`,
      giteaRepoName: repo.name || repoFullName.split('/').pop(),
      repoFullName,
    }

    if (subdomain) payload.subdomain = subdomain
    if (previewUrl) payload.previewUrl = previewUrl

    if (!existing[0]) {
      payload.status = 'synced'
      created += 1
    } else {
      updated += 1
    }

    await upsertWebsiteProjectByRepo(repoFullName, payload)
  }

  return { synced: repos.length, created, updated }
}

export async function ensureSubdomainAvailable(subdomain) {
  const docs = await listDocuments(config.collections.websiteProjects, [
    Query.equal('subdomain', subdomain),
    Query.limit(1),
  ])
  if (docs[0]) {
    const error = new Error(`Subdomain "${subdomain}" ist bereits vergeben`)
    error.status = 409
    throw error
  }
}

export async function generateRepoFromTemplate({ owner, repoName }) {
  const templateOwner = config.gitea.templateOwner
  const templateRepo = config.gitea.templateRepo
  const targetOwner = owner || config.gitea.defaultOwner

  if (!targetOwner) {
    throw new Error('GITEA_DEFAULT_OWNER fehlt in .env')
  }

  return giteaFetch(`/repos/${templateOwner}/${templateRepo}/generate`, {
    method: 'POST',
    body: JSON.stringify({
      owner: targetOwner,
      name: repoName,
      private: false,
      description: `Website-Projekt ${repoName}`,
      git_content: true,
    }),
  })
}

async function waitForRepoBranch(owner, repo, preferredBranch = 'main', maxAttempts = 15, delayMs = 400) {
  for (let attempt = 1; attempt <= maxAttempts; attempt += 1) {
    try {
      const repoInfo = await giteaFetch(`/repos/${owner}/${repo}`)
      const branches = await giteaFetch(`/repos/${owner}/${repo}/branches?limit=50`)
      const branchNames = Array.isArray(branches) ? branches.map((entry) => entry.name) : []

      if (branchNames.includes(preferredBranch)) return preferredBranch
      if (repoInfo?.default_branch && branchNames.includes(repoInfo.default_branch)) {
        return repoInfo.default_branch
      }
      if (branchNames.length > 0) return branchNames[0]
    } catch {
      /* retry */
    }
    await new Promise((resolve) => setTimeout(resolve, delayMs))
  }

  throw new Error(`Branch "${preferredBranch}" existiert im Repository ${owner}/${repo} noch nicht`)
}

async function updatePreviewConfigFile(repoFullName, previewConfig, branch = 'main') {
  const [owner, repo] = repoFullName.split('/')
  const content = JSON.stringify(previewConfig, null, 2) + '\n'
  const encoded = Buffer.from(content).toString('base64')

  let sha = null
  try {
    const existing = await giteaFetch(
      `/repos/${owner}/${repo}/contents/.webklar-preview.json?ref=${encodeURIComponent(branch)}`
    )
    sha = existing.sha
  } catch {
    /* file may not exist yet */
  }

  await giteaFetch(`/repos/${owner}/${repo}/contents/.webklar-preview.json`, {
    method: sha ? 'PUT' : 'POST',
    body: JSON.stringify({
      message: 'Update preview config from ticket system',
      content: encoded,
      branch,
      ...(sha ? { sha } : {}),
    }),
  })
}

export async function createProjectFromTemplate({
  repoName,
  displayName,
  subdomain,
  customerId = '',
  ticketId = '',
  owner,
}) {
  const targetOwner = owner || config.gitea.defaultOwner
  const safeRepoName = slugify(repoName) || slugify(displayName) || slugify(subdomain)
  // Subdomain ist optional: ohne Subdomain wird nur das Repo angelegt (normales
  // Projekt ohne Website-Preview), mit Subdomain zusaetzlich deployed.
  const safeSubdomain = slugify(subdomain)
  const hasWebsite = Boolean(safeSubdomain)

  if (!safeRepoName) {
    throw new Error('repoName oder displayName ist erforderlich')
  }

  if (hasWebsite) {
    await ensureSubdomainAvailable(safeSubdomain)
  }

  const repo = await generateRepoFromTemplate({
    owner: targetOwner,
    repoName: safeRepoName,
  })

  const repoFullName = repo.full_name || `${targetOwner}/${safeRepoName}`
  const [repoOwner, repoSlug] = repoFullName.split('/')
  const branch = await waitForRepoBranch(repoOwner, repoSlug, 'main')
  const previewConfig = {
    enabled: hasWebsite,
    type: 'static',
    branch,
    displayName: displayName || safeRepoName,
    ...(hasWebsite ? { subdomain: safeSubdomain } : {}),
    templateName: config.gitea.templateRepo,
  }

  await updatePreviewConfigFile(repoFullName, previewConfig, branch)

  let deployResult = { deployed: false, skipped: !hasWebsite }
  if (hasWebsite) {
    try {
      deployResult = await runDeploy(repoFullName, branch, previewConfig)
    } catch (deployErr) {
      console.error('[giteaAdmin] deploy failed:', deployErr.message)
      deployResult = { deployed: false, error: deployErr.message }
    }
  }

  const previewUrl = hasWebsite ? buildPreviewUrl(safeSubdomain) : ''
  const project = await upsertWebsiteProjectByRepo(repoFullName, {
    customerId,
    ticketId,
    projectName: previewConfig.displayName,
    templateName: config.gitea.templateRepo,
    giteaRepoUrl: repo.html_url || `${config.gitea.baseUrl}/${repoFullName}`,
    giteaRepoName: repo.name || safeRepoName,
    repoFullName,
    subdomain: safeSubdomain,
    previewUrl,
    projectType: hasWebsite ? 'website' : 'repo',
    status: hasWebsite ? (deployResult.deployed ? 'deployed' : 'pending') : 'created',
    provisioningStatus: hasWebsite
      ? (deployResult.deployed ? 'ready' : 'deploy_failed')
      : 'ready',
  })

  return {
    projectId: project.$id,
    repoFullName,
    previewUrl,
    subdomain: safeSubdomain,
    projectType: hasWebsite ? 'website' : 'repo',
    deploy: deployResult,
  }
}

/** Repo-Basisdaten (Groesse in KB, Default-Branch). */
export async function getRepoInfo(repoFullName) {
  const [owner, repo] = String(repoFullName || '').split('/')
  if (!owner || !repo) return null
  const data = await giteaFetch(`/repos/${owner}/${repo}`)
  return {
    sizeKb: Number(data.size || 0),
    defaultBranch: data.default_branch || 'main',
    updatedAt: data.updated_at || '',
    htmlUrl: data.html_url || `${config.gitea.baseUrl}/${repoFullName}`,
  }
}

/** Letzte Commits eines Repos (volle Message inkl. Body). */
export async function listRepoCommits(repoFullName, { branch = 'main', limit = 20 } = {}) {
  const [owner, repo] = String(repoFullName || '').split('/')
  if (!owner || !repo) return []
  // stat/verification/files abschalten - sonst berechnet Gitea Diff-Stats pro Commit
  const data = await giteaFetch(
    `/repos/${owner}/${repo}/commits?sha=${encodeURIComponent(branch)}&limit=${limit}&stat=false&verification=false&files=false`
  )
  return (Array.isArray(data) ? data : []).map((entry) => ({
    sha: entry.sha || '',
    shortSha: (entry.sha || '').slice(0, 7),
    message: entry.commit?.message || '',
    authorName:
      entry.commit?.author?.name || entry.author?.login || entry.committer?.login || 'Unbekannt',
    date: entry.commit?.author?.date || entry.created || '',
    url: entry.html_url || `${config.gitea.baseUrl}/${repoFullName}/commit/${entry.sha}`,
  }))
}

/**
 * Datei-Uebersicht: aggregiert den Git-Baum serverseitig nach Top-Level-Eintraegen
 * (nie den rohen Baum ans Frontend geben - kann tausende Eintraege haben).
 */
export async function getRepoTreeSummary(repoFullName, ref = 'main') {
  const [owner, repo] = String(repoFullName || '').split('/')
  if (!owner || !repo) return null
  const data = await giteaFetch(
    `/repos/${owner}/${repo}/git/trees/${encodeURIComponent(ref)}?recursive=true&per_page=1000`
  )

  const entries = Array.isArray(data?.tree) ? data.tree : []
  const topLevelMap = new Map()
  let totalFiles = 0
  let totalSizeBytes = 0

  for (const entry of entries) {
    const isBlob = entry.type === 'blob'
    const size = isBlob ? Number(entry.size || 0) : 0
    const path = String(entry.path || '')
    const slash = path.indexOf('/')
    const topSegment = slash === -1 ? path : path.slice(0, slash)
    const isDir = slash !== -1 || entry.type === 'tree'

    if (isBlob) {
      totalFiles += 1
      totalSizeBytes += size
    }

    if (!topSegment) continue
    const existing = topLevelMap.get(topSegment) || {
      path: topSegment,
      type: isDir ? 'dir' : 'file',
      fileCount: 0,
      sizeBytes: 0,
    }
    if (isDir) existing.type = 'dir'
    if (isBlob) {
      existing.fileCount += 1
      existing.sizeBytes += size
    }
    topLevelMap.set(topSegment, existing)
  }

  const topLevel = [...topLevelMap.values()]
    .sort((a, b) => b.sizeBytes - a.sizeBytes)
    .slice(0, 50)

  return {
    totalFiles,
    totalSizeBytes,
    truncated: Boolean(data?.truncated),
    topLevel,
  }
}

const README_CANDIDATES = ['README.md', 'readme.md', 'Readme.md', 'README.MD', 'README']

export async function fetchRepoReadme(repoFullName) {
  const [owner, repo] = repoFullName.split('/')
  if (!owner || !repo) {
    const error = new Error('repoFullName muss owner/repo sein')
    error.status = 400
    throw error
  }

  for (const filename of README_CANDIDATES) {
    try {
      const data = await giteaFetch(
        `/repos/${owner}/${repo}/contents/${encodeURIComponent(filename)}`
      )
      const encoding = data.encoding || 'base64'
      const raw = encoding === 'base64'
        ? Buffer.from(data.content || '', 'base64').toString('utf8')
        : String(data.content || '')
      return {
        filename: data.name || filename,
        content: raw,
        htmlUrl: data.html_url || `${config.gitea.baseUrl}/${repoFullName}/src/branch/main/${filename}`,
      }
    } catch (err) {
      if (err.status === 404) continue
      throw err
    }
  }

  return null
}