'use strict'

const fs = require('fs')
const fsp = fs.promises
const path = require('path')
const { DIRS, readJson, writeJson, toPortablePath, resolvePortablePath } = require('./paths')
const { dedupeDir, copyTree, treeSize, removeTree } = require('./fsutil')
const { normalizeLabel } = require('./names')
const { rewireSymlinks, restoreExecutableBits, EXEC_NAMES } = require('./symlinks')

const WINES_DIR = DIRS.WINES
const REGISTRY = path.join(DIRS.DATA, 'wines.json')
const DEFAULT_KEY = 'defaultWine'

function exists(p) {
  try {
    fs.accessSync(p)
    return true
  } catch {
    return false
  }
}

function detectType(dir) {
  if (exists(path.join(dir, 'proton'))) return 'proton'
  for (const rel of ['files/bin/wine', 'bin/wine', 'dist/bin/wine']) {
    if (exists(path.join(dir, rel))) return 'wine'
  }
  return null
}

function findWineBinary(dir) {
  for (const rel of ['files/bin/wine', 'bin/wine', 'dist/bin/wine']) {
    const p = path.join(dir, rel)
    if (exists(p)) return p
  }
  return null
}

function versionOf(wineBin, env) {
  try {
    const { execFileSync } = require('child_process')
    const out = execFileSync(wineBin, ['--version'], {
      timeout: 15000,
      env: { ...process.env, ...env, WINEPREFIX: path.join(DIRS.DATA, 'probe-prefix') }
    })
    return String(out).trim().replace(/^wine-?/i, '')
  } catch {
    return ''
  }
}

function labelFor(type, dir, version) {
  const name = path.basename(dir)
  if (type === 'proton') return /GE|CachyOS|TKG/i.test(name) ? name : (version ? `Proton ${version}` : name)
  return version ? `Wine ${version}` : name
}

async function scanBuild(dir, depth) {
  const type = detectType(dir)
  if (type) {
    const entry = {
      id: path.basename(dir).toLowerCase().replace(/[^a-z0-9._-]+/g, '-'),
      name: path.basename(dir),
      path: dir,
      type
    }
    if (type === 'proton') {
      entry.wineBin = path.join(dir, 'proton')
    } else if (type === 'wine') {
      const bin = findWineBinary(dir)
      if (bin) {
        entry.wineBin = bin
        const ver = versionOf(bin, {})
        if (ver) entry.version = ver
      }
    }
    entry.label = labelFor(type, dir, entry.version)
    return [entry]
  }
  if (depth <= 0) return []
  const out = []
  let names = []
  try {
    names = await fsp.readdir(dir)
  } catch {
    return out
  }
  for (const name of names) {
    const sub = path.join(dir, name)
    let st
    try {
      st = await fsp.stat(sub)
    } catch {
      continue
    }
    if (st.isDirectory() && name !== 'wineprefixes' && name !== 'share') {
      out.push(...(await scanBuild(sub, depth - 1)))
    }
  }
  return out
}

async function refreshWines() {
  let found = []
  try {
    found = await scanBuild(WINES_DIR, 2)
  } catch {
    found = []
  }
  const prev = readJson(REGISTRY, []).map(wineAbs)
  const prevById = new Map(prev.map(w => [w.id, w]))
  // A build whose path changed since last scan was moved (or the launcher
  // itself was) - rewire its absolute symlinks to the current location. A
  // build that cannot be executed (no exec bit on proton/wine - exactly what
  // a sync from a PLWL that predates permission transfer leaves behind) is
  // healed here instead: two access() calls per build, and only a broken build
  // pays for the walk. Without it such a build stays dead weight forever.
  for (const w of found) {
    const old = prevById.get(w.id)
    const moved = !old || old.path !== w.path
    if (moved || buildAuditFailed(w.path, w.wineBin)) {
      try {
        await healBuild(w.path)
      } catch {}
    }
  }
  const disabled = new Set(prev.filter(w => w.disabled).map(w => w.id))
  // a display name the user gave the build has to survive every rescan, just
  // like the disabled flag (both live in the registry, not in the folder)
  const renamed = new Map(prev.filter(w => w.displayName).map(w => [w.id, w.displayName]))
  for (const w of found) {
    if (disabled.has(w.id)) w.disabled = true
    if (renamed.has(w.id)) w.displayName = renamed.get(w.id)
    applyDisplayName(w)
  }
  writeJson(REGISTRY, found.map(wineRel))
  return found
}

// Stored relative to FILES (portable), resolved to absolute for use - same
// scheme as the game registry. `id`, `name`, `label`, `version`, `type` pass through.
function wineAbs(w) {
  return applyDisplayName({ ...w, path: resolvePortablePath(w.path), wineBin: resolvePortablePath(w.wineBin) })
}

function wineRel(w) {
  return { ...w, path: toPortablePath(w.path), wineBin: toPortablePath(w.wineBin) }
}

function getWines() {
  return readJson(REGISTRY, []).map(wineAbs)
}

function getWine(id) {
  return getWines().find(w => w.id === id) || null
}

// What the user typed wins over the folder-derived label everywhere the
// build is shown (library config, settings, Open with popup). Every registry
// read goes through here, so a stale stored label can never leak out.
function applyDisplayName(w) {
  if (w && w.displayName) w.label = w.displayName
  return w
}

// A build keeps its folder and id (apps point at the id, and prefix symlinks
// point inside the folder), so "renaming" only changes the shown label.
function setWineDisplayName(id, name) {
  const wines = getWines()
  const w = wines.find(x => x.id === id)
  if (!w) return { ok: false, error: 'notFound' }
  if (w.type === 'system') return { ok: false, error: 'isSystem' }
  const clean = normalizeLabel(name)
  if (!clean) return { ok: false, error: 'invalidName' }
  w.displayName = clean
  applyDisplayName(w)
  writeJson(REGISTRY, wines.map(wineRel))
  return { ok: true, displayName: clean }
}

function setWineDisabled(id, disabled) {
  const wines = getWines()
  const w = wines.find(x => x.id === id)
  if (w) {
    w.disabled = !!disabled
    writeJson(REGISTRY, wines.map(wineRel))
  }
  return wines
}

function getDefaultWine() {
  return require('./library').loadSettings().defaultWine || 'system'
}

// Resolve the wine build a run should use: 'default'/'system'/unknown all
// fall back to System Wine. Shared by the games service and the ad-hoc
// "open with" runner.
function resolveWine(id) {
  const system = { id: 'system', type: 'system', label: 'System Wine' }
  const wanted = id === 'default' ? getDefaultWine() : id
  if (!wanted || wanted === 'system') return system
  return getWine(wanted) || system
}

function setDefaultWine(id) {
  const wines = getWines()
  if (id !== 'system' && !wines.some(w => w.id === id)) return { ok: false, error: 'notFound' }
  require('./library').saveSettings({ defaultWine: id })
  return { ok: true, defaultWine: id }
}

// Same measured removal as a prefix (staging, then a bar driven by the files
// walking out): a build folder is multi-GB.
async function deleteWine(id, onProgress) {
  const wines = getWines()
  const w = wines.find(x => x.id === id)
  if (!w || w.system) return { ok: false, error: w ? 'isSystem' : 'notFound' }
  const emit = (phase, detail) => {
    if (onProgress) onProgress({ phase, label: w.label || w.name || id, ...detail })
  }
  emit('count', { files: 0, bytes: 0 })
  const total = await treeSize(w.path)
  await removeTree(w.path, p => emit('remove', { files: p.files, bytes: p.bytes, totalFiles: total.files, totalBytes: total.bytes }))
  writeJson(REGISTRY, wines.filter(x => x.id !== id).map(wineRel))
  if (getDefaultWine() === id) require('./library').saveSettings({ defaultWine: 'system' })
  return { ok: true }
}

// --- symlink healing -------------------------------------------------------
// Wine/Proton builds contain symlinks (e.g. inside the bundled default prefix)
// that point to absolute paths from wherever the build lived before (zip
// layout, previous install dir). After the build or the whole launcher is
// moved those links dangle and Proton crashes during prefix setup
// (try_copy -> FileNotFoundError). The rewiring itself lives in symlinks.js
// because prefixes, synced apps and game imports need exactly the same thing.
async function fixBuildSymlinks(root) {
  return rewireSymlinks(root, [DIRS.FILES])
}

// Everything a freshly arrived build needs before it can run: relative links
// and executable binaries. Returns what was changed, for the callers' reports.
async function healBuild(root) {
  const links = await fixBuildSymlinks(root)
  const executables = await restoreExecutableBits(root)
  return { links, executables }
}

function isExec(p) {
  try {
    fs.accessSync(p, fs.constants.X_OK)
    return true
  } catch {
    return false
  }
}

// Where a wine/proton build keeps the programs wine itself spawns (wine,
// wineserver, wineboot, ...) and the loaders next to the shared libraries.
const AUDIT_DIRS = ['files/bin', 'bin', 'dist/bin', 'files/lib/wine/x86_64-unix', 'files/lib/wine/i386-unix']

// Is this build missing a permission it needs to run? A build synced from a
// PLWL that predates permission transfer has no executable bit anywhere, and
// that stays invisible until the user presses Play (spawn fails with EACCES).
// Auditing is a handful of directory listings - only a build that FAILS it
// pays for the full walk, and the audit says nothing about a healthy build on
// every later start.
function buildAuditFailed(root, wineBin) {
  if (!root) return false
  if (wineBin && !isExec(wineBin)) return true
  for (const rel of AUDIT_DIRS) {
    const dir = path.join(root, rel)
    let entries = []
    try {
      entries = fs.readdirSync(dir, { withFileTypes: true })
    } catch {
      continue
    }
    const inBin = path.basename(rel) === 'bin'
    for (const entry of entries) {
      if (!entry.isFile()) continue
      if (!inBin && !EXEC_NAMES.has(entry.name)) continue
      if (!isExec(path.join(dir, entry.name))) return true
    }
  }
  return false
}

async function importWineFolder(srcDir, onProgress) {
  const type = detectType(srcDir)
  let copySrc = srcDir
  if (!type) {
    // the user picked a folder one level above the actual build
    let subs = []
    try {
      subs = (await fsp.readdir(srcDir, { withFileTypes: true })).filter(e => e.isDirectory())
    } catch {}
    const build = subs.find(s => detectType(path.join(srcDir, s.name)))
    if (build) copySrc = path.join(srcDir, build.name)
  }
  const dst = dedupeDir(WINES_DIR, path.basename(copySrc))
  // a wine/proton build is big enough that the copy needs a real bar: count it
  // first (staging), then report bytes as they land while it copies
  const emit = (phase, detail) => {
    if (onProgress) onProgress({ phase, label: path.basename(dst), ...detail })
  }
  emit('count', { files: 0, bytes: 0 })
  const total = await treeSize(copySrc)
  await copyTree(copySrc, dst, p => emit('copy', { files: p.done, bytes: p.bytes, totalFiles: total.files, totalBytes: total.bytes }))
  let healed = { links: 0, executables: 0 }
  try {
    healed = await healBuild(dst)
  } catch {}
  await refreshWines()
  // the toast shows a portable-looking path (files/...) like everywhere else
  return { ok: true, path: toPortablePath(dst), symlinksFixed: healed.links, executablesFixed: healed.executables }
}

module.exports = { refreshWines, getWines, getWine, resolveWine, setWineDisabled, setWineDisplayName, getDefaultWine, setDefaultWine, deleteWine, importWineFolder, findWineBinary, detectType, fixBuildSymlinks, healBuild }