import { config } from '../config.js'
import {
  upsertWebsiteProjectByRepo,
  listDocuments,
  Query,
  getDocument,
  updateDocument,
} from './appwriteAdmin.js'
import {
  runDeploy,
  deployKeepsStatus,
  buildPreviewUrl,
  removeDeploy,
  syncPreviewTls,
  fetchPreviewConfig,
} from './previewDeploy.js'
import { giteaFetch } from './giteaClient.js'
import { slugify } from './slug.js'
import { withLocks } from './keyedLock.js'
import { repoLockKey } from './repoMove.js'

// Sicherheitsnetz wie bei listRecentPushes (siehe pushHistory.js, Controller-Ruling R8): sollte
// Gitea "page" ignorieren und immer dieselbe volle Seite liefern, blaettert die Schleife nicht
// endlos weiter (40 x 50 = 2000 Repos).
const MAX_REPO_PAGES = 40

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
    if (page >= MAX_REPO_PAGES) {
      console.warn(
        `[giteaAdmin] mehr als ${MAX_REPO_PAGES} Seiten Repos – weitere Repos werden nicht gelistet`
      )
      break
    }
    page += 1
  }

  return repos
}

/**
 * Findet Repos, die in Gitea liegen, aber noch kein Appwrite-Projektdokument haben, und legt fuer
 * jedes nicht archivierte ein minimales Dokument an (status "synced", ohne Hosting/Subdomain) -
 * ohne dass dafuer manuell "Abgleich" gedrueckt werden muesste. Wird vom Projekt-Dialog bei jedem
 * Oeffnen aufgerufen, laeuft also oft: die aeussere `withLocks(['import'])`-Sperre serialisiert
 * parallele Laeufe komplett (ein zweiter Aufruf sieht danach garantiert den Stand des ersten), die
 * innere `withLocks([repoLockKey(...)])` je neuem Repo schuetzt zusaetzlich gegen andere
 * gleichzeitige Schreiber desselben Projektdokuments (z. B. Umzug/Zuweisung).
 */
export async function importNewRepos() {
  return withLocks(['import'], async () => {
    const [repos, docs] = await Promise.all([
      listAllAccessibleRepos(),
      listDocuments(config.collections.websiteProjects, [Query.limit(5000)]),
    ])

    // Ohne Ruecksicht auf Gross-/Kleinschreibung vergleichen (Controller-Ruling).
    const existingNames = new Set(
      docs.map((d) => String(d.repoFullName || '').toLowerCase()).filter(Boolean)
    )

    let created = 0
    const createdRepos = []
    for (const repo of repos) {
      const fullName = repo.full_name
      if (!fullName || repo.archived) continue
      if (existingNames.has(fullName.toLowerCase())) continue

      await withLocks([repoLockKey(fullName)], async () => {
        const recheck = await listDocuments(config.collections.websiteProjects, [
          Query.equal('repoFullName', fullName),
          Query.limit(1),
        ])
        if (recheck[0]) return

        const doc = await upsertWebsiteProjectByRepo(fullName, {
          projectName: repo.description || repo.name || fullName.split('/').pop(),
          giteaRepoUrl: repo.html_url,
          giteaRepoName: repo.name,
          repoFullName: fullName,
          archived: false,
          status: 'synced',
          giteaSyncedAt: new Date().toISOString(),
        })
        created += 1
        createdRepos.push({ projectId: doc.$id, repo })
      })
    }

    return { created, createdRepos }
  })
}

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 payload = {
      projectName: repo.description || repo.name || repoFullName.split('/').pop(),
      giteaRepoUrl: repo.html_url || `${config.gitea.baseUrl}/${repoFullName}`,
      giteaRepoName: repo.name || repoFullName.split('/').pop(),
      repoFullName,
      // In Gitea archivierte Repos werden im Ticketsystem ausgeblendet.
      archived: Boolean(repo.archived),
    }

    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 } : {}),
    }),
  })
}

/**
 * true, wenn zu diesem Projekt wirklich ein Hosting gehoert (Preview/Website/Vorlage, oder ein
 * bereits deployter bzw. anstehender Stand) - im Unterschied zu einem nur importierten/
 * abgeglichenen Repo ohne eigenes Hosting (z. B. status "synced" ohne Website). Bestimmt u. a.,
 * ob die Selbstheilung (ensureRepoPreviewConfig) fuer dieses Projekt ueberhaupt aktiv werden darf -
 * sonst wuerde mit dem organisationsweiten Webhook jeder Push in ein bloss abgeglichenes Repo eine
 * Preview anlegen.
 */
export function isHostedProject(doc) {
  if (['preview', 'website', 'template'].includes(doc?.projectType)) return true
  if (['deployed', 'pending'].includes(doc?.status)) return true
  return false
}

/**
 * Selbstheilung fuer eine geloeschte/fehlende .webklar-preview.json:
 * Rekonstruiert die Hosting-Config aus dem in Appwrite gespeicherten
 * Projektstand (Subdomain, Typ, Name), schreibt sie ins Repo zurueck und liefert
 * sie fuer einen sofortigen Deploy zurueck. Gibt null zurueck, wenn zu dem Repo
 * kein gehostetes, aktives Projekt bekannt ist (dann bleibt es Repo-only).
 */
export async function ensureRepoPreviewConfig(repoFullName, branch = 'main') {
  if (!repoFullName) return null
  const docs = await listDocuments(config.collections.websiteProjects, [
    Query.equal('repoFullName', repoFullName),
    Query.limit(1),
  ])
  const doc = docs[0]
  if (!doc || doc.archived) return null
  if (!isHostedProject(doc)) return null

  const type = deriveProjectType(doc)
  const subdomain = doc.subdomain || ''
  if (!subdomain) return null

  const previewConfig = {
    enabled: true,
    type: 'static',
    branch,
    displayName: doc.projectName || repoFullName.split('/').pop(),
    templateName: doc.templateName || config.gitea.templateRepo,
    projectType: type,
    public: type === 'website',
    template: type === 'template',
    subdomain,
  }

  try {
    await updatePreviewConfigFile(repoFullName, previewConfig, branch)
  } catch (err) {
    console.error('[ensureRepoPreviewConfig] .webklar-preview.json zurueckschreiben fehlgeschlagen:', err.message)
  }
  return previewConfig
}

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',
    ...(hasWebsite && deployKeepsStatus(deployResult)
      ? {} // Preview-Runner (C1): Status setzt der Verfolger
      : {
          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,
  }
}

/**
 * Leitet den Projekt-Typ aus einem bestehenden Dokument ab, wenn im Request
 * kein expliziter Typ mitgegeben wurde.
 *   preview  -> Website mit Login-geschuetzter Preview (Standard)
 *   website  -> oeffentliche Website ohne Login
 *   template -> Website-Vorlage (login-geschuetzt, nur Admin, in Vorlagen-Ansicht)
 *   project  -> internes Projekt ohne Hosting/Subdomain
 */
function deriveProjectType(doc) {
  if (doc?.isTemplate) return 'template'
  if (doc?.isPublic) return 'website'
  if (doc?.subdomain) return 'preview'
  return 'project'
}

async function patchGiteaRepo(repoFullName, body) {
  const [owner, repo] = String(repoFullName || '').split('/')
  if (!owner || !repo) return null
  return giteaFetch(`/repos/${owner}/${repo}`, {
    method: 'PATCH',
    body: JSON.stringify(body),
  })
}

/**
 * Bearbeitet ein bestehendes Website-Projekt (Name / Subdomain / Typ) und
 * synchronisiert die Aenderung ueber ALLE Systeme:
 *   - Appwrite-Dokument (projectName, subdomain, previewUrl, projectType, isPublic, status)
 *   - Gitea: .webklar-preview.json (enabled/subdomain/displayName/public) + Repo-Beschreibung
 *   - Preview-Hosting: Redeploy in neues Verzeichnis, altes entfernen, Traefik-TLS neu
 * Der Gitea-Repo-Slug/die Klon-URL bleiben bewusst stabil (kein Repo-Rename).
 */
export async function updateWebsiteProject(projectId, { projectName, subdomain, projectType } = {}) {
  const doc = await getDocument(config.collections.websiteProjects, projectId)
  if (!doc) {
    const error = new Error('Projekt nicht gefunden')
    error.status = 404
    throw error
  }

  const repoFullName = doc.repoFullName || ''
  const [owner, repoSlug] = repoFullName.split('/')

  const nextName = String(projectName ?? doc.projectName ?? '').trim() || doc.projectName || repoSlug || ''
  const nextType = projectType || deriveProjectType(doc)
  // template = login-geschuetzte Vorlage: braucht Preview (wie 'preview'), aber
  // nicht oeffentlich; wird als isTemplate markiert.
  const hasWebsite = nextType === 'preview' || nextType === 'website' || nextType === 'template'
  const isPublic = nextType === 'website'
  const isTemplate = nextType === 'template'

  const oldSubdomain = doc.subdomain || ''
  let nextSubdomain = ''
  if (hasWebsite) {
    const requested = slugify(subdomain !== undefined ? subdomain : oldSubdomain)
    nextSubdomain = requested || slugify(repoSlug)
  }
  const subdomainChanged = nextSubdomain !== oldSubdomain

  // Subdomain-Eindeutigkeit pruefen (eigenes Dokument ignorieren)
  if (hasWebsite && subdomainChanged && nextSubdomain) {
    const conflicts = await listDocuments(config.collections.websiteProjects, [
      Query.equal('subdomain', nextSubdomain),
      Query.limit(5),
    ])
    if (conflicts.some((c) => c.$id !== projectId)) {
      const error = new Error(`Subdomain "${nextSubdomain}" ist bereits vergeben`)
      error.status = 409
      throw error
    }
  }

  let branch = 'main'
  try {
    const info = await getRepoInfo(repoFullName)
    branch = info?.defaultBranch || 'main'
  } catch {
    /* Default main */
  }

  // Deploy-Typ (z.B. node_build) und index-Unterordner aus der vorhandenen
  // Repo-Config uebernehmen - sonst wuerde jedes Bearbeiten im Portal
  // App-Projekte (Expo/Vite/React) wieder auf "static" zuruecksetzen.
  let existingCfg = null
  try {
    existingCfg = await fetchPreviewConfig(repoFullName, branch)
  } catch {
    /* keine bestehende Config -> Defaults */
  }

  const previewConfig = {
    enabled: hasWebsite,
    type: existingCfg?.type || 'static',
    ...(existingCfg?.index ? { index: existingCfg.index } : {}),
    branch,
    displayName: nextName,
    templateName: doc.templateName || config.gitea.templateRepo,
    projectType: nextType,
    public: isPublic,
    template: isTemplate,
    ...(hasWebsite && nextSubdomain ? { subdomain: nextSubdomain } : {}),
  }

  if (owner && repoSlug) {
    try {
      await updatePreviewConfigFile(repoFullName, previewConfig, branch)
    } catch (err) {
      console.error('[updateWebsiteProject] preview-config schreiben fehlgeschlagen:', err.message)
    }
    try {
      await patchGiteaRepo(repoFullName, { description: nextName })
    } catch (err) {
      console.error('[updateWebsiteProject] Gitea-Beschreibung fehlgeschlagen:', err.message)
    }
  }

  // Deploy / Teardown
  let deployResult = { deployed: false, skipped: true }
  if (hasWebsite && nextSubdomain) {
    if (subdomainChanged && oldSubdomain) {
      try { await removeDeploy(oldSubdomain) } catch (err) {
        console.error('[updateWebsiteProject] alten Deploy entfernen fehlgeschlagen:', err.message)
      }
    }
    try {
      deployResult = await runDeploy(repoFullName, branch, previewConfig, { project: doc })
    } catch (err) {
      console.error('[updateWebsiteProject] deploy fehlgeschlagen:', err.message)
      deployResult = { deployed: false, error: err.message }
    }
  } else if (oldSubdomain) {
    try { await removeDeploy(oldSubdomain) } catch (err) {
      console.error('[updateWebsiteProject] Deploy entfernen fehlgeschlagen:', err.message)
    }
  }

  const previewUrl = hasWebsite && nextSubdomain ? buildPreviewUrl(nextSubdomain) : ''
  const updated = await updateDocument(config.collections.websiteProjects, projectId, {
    projectName: nextName,
    subdomain: nextSubdomain,
    previewUrl,
    projectType: nextType,
    isPublic,
    isTemplate,
    ...(hasWebsite && deployKeepsStatus(deployResult)
      ? {} // Preview-Runner (C1): Status setzt der Verfolger
      : {
          status: hasWebsite ? (deployResult.deployed ? 'deployed' : 'pending') : 'created',
          provisioningStatus: hasWebsite
            ? (deployResult.deployed ? 'ready' : (deployResult.error ? 'deploy_failed' : 'pending'))
            : 'ready',
        }),
    updatedAt: new Date().toISOString(),
  })

  // TLS-Router NACH dem Appwrite-Update synchronisieren, damit der public/auth-
  // Zustand (isPublic) korrekt gelesen wird - auch wenn kein Redeploy stattfand
  // (z.B. nur Typ preview <-> website getauscht).
  try { await syncPreviewTls() } catch (err) {
    console.error('[updateWebsiteProject] TLS-Sync fehlgeschlagen:', err.message)
  }

  // Website-Analyse: Berechtigung/Domains neu pruefen (dynamischer Import wegen Zyklus); Fehler aendern das Ergebnis nicht
  try {
    const { analyseOnProjectChanged } = await import('./analyse.js')
    await analyseOnProjectChanged(projectId)
  } catch (err) {
    console.error('[updateWebsiteProject] Analyse-Abgleich fehlgeschlagen:', err.message)
  }

  return {
    project: updated,
    deploy: deployResult,
    previewUrl,
    subdomain: nextSubdomain,
    projectType: nextType,
    isPublic,
  }
}

/**
 * Archiviert (oder reaktiviert) ein Projekt: setzt das Gitea-Repo auf archived
 * und pflegt das Appwrite-Flag. Beim Archivieren wird zusaetzlich der Preview-
 * Deploy entfernt; beim Reaktivieren mit Subdomain neu deployt.
 */
export async function archiveRepo(projectId, archived = true) {
  const doc = await getDocument(config.collections.websiteProjects, projectId)
  if (!doc) {
    const error = new Error('Projekt nicht gefunden')
    error.status = 404
    throw error
  }

  const repoFullName = doc.repoFullName || ''
  let repoMissing = false
  if (repoFullName.includes('/')) {
    try {
      await patchGiteaRepo(repoFullName, { archived: Boolean(archived) })
    } catch (err) {
      // Verwaistes Projekt: Repo existiert nicht mehr in Gitea (404). Dann trotzdem
      // nur das Appwrite-Dokument (ent)archivieren, damit es aus der Liste verschwindet.
      if (err.status === 404) {
        repoMissing = true
        console.warn(`[archiveRepo] Gitea-Repo ${repoFullName} nicht gefunden (404) - nur Appwrite wird aktualisiert`)
      } else {
        const error = new Error('Gitea-Archivierung fehlgeschlagen: ' + err.message)
        error.status = err.status || 500
        throw error
      }
    }
  }

  if (archived && doc.subdomain) {
    try { await removeDeploy(doc.subdomain) } catch (err) {
      console.error('[archiveRepo] Deploy entfernen fehlgeschlagen:', err.message)
    }
  }

  if (!archived && !repoMissing && doc.subdomain) {
    try {
      const branch = (await getRepoInfo(repoFullName))?.defaultBranch || 'main'
      const cfg = (await fetchPreviewConfig(repoFullName, branch)) || {
        enabled: true,
        type: 'static',
        branch,
        subdomain: doc.subdomain,
        displayName: doc.projectName,
      }
      await runDeploy(repoFullName, branch, cfg, { project: doc })
    } catch (err) {
      console.error('[archiveRepo] Redeploy bei Reaktivierung fehlgeschlagen:', err.message)
    }
  }

  const updated = await updateDocument(config.collections.websiteProjects, projectId, {
    archived: Boolean(archived),
    ...(archived ? { status: 'archived' } : {}),
    updatedAt: new Date().toISOString(),
  })

  return { project: updated, archived: Boolean(archived) }
}

/** 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
}