/**
 * Host Docker CLI terminal — line-buffered input, xterm FitAddon, binary-safe I/O.
 */
import { manager, Methods } from '../client/manager.js'
import {
  getTerminalCtor,
  getFitAddonCtor,
  defaultXtermOptions,
  decodePayload,
  createFitController,
  safeFit,
} from './xtermUtils.js'

const Terminal = getTerminalCtor()
const FitAddon = getFitAddonCtor()

let dockerTerminalSession = null
let dockerTerminalFontSize = 14
let dockerTerminalTheme = 'dark'

const dockerTerminalThemes = {
  dark: defaultXtermOptions().theme,
  light: {
    background: '#ffffff',
    foreground: '#0f172a',
    cursor: '#0f172a',
    selectionBackground: '#b3d4fc',
  },
  'solarized-dark': {
    background: '#002b36',
    foreground: '#839496',
    cursor: '#93a1a1',
    selectionBackground: '#073642',
  },
  'solarized-light': {
    background: '#fdf6e3',
    foreground: '#657b83',
    cursor: '#586e75',
    selectionBackground: '#eee8d5',
  },
  monokai: {
    background: '#272822',
    foreground: '#f8f8f2',
    cursor: '#f8f8f0',
    selectionBackground: '#49483e',
  },
}

const ALLOWED_DOCKER_COMMANDS = new Set([
  'ps',
  'images',
  'volumes',
  'networks',
  'info',
  'version',
  'logs',
  'inspect',
  'stats',
  'top',
  'diff',
  'port',
  'history',
  'search',
  'events',
  'system',
  'help',
  'container',
  'image',
  'network',
  'volume',
  'context',
  'compose',
])

const BLOCKED_COMMANDS = new Set([
  'exec',
  'run',
  'create',
  'start',
  'stop',
  'restart',
  'kill',
  'rm',
  'rmi',
  'prune',
  'build',
  'commit',
  'push',
  'pull',
  'tag',
  'load',
  'save',
  'import',
  'export',
  'cp',
  'update',
  'login',
  'logout',
  'swarm',
  'plugin',
  'secret',
  'config',
  'service',
  'node',
  'stack',
])

const BLOCKED_PATTERNS = [
  /rm\s+-/,
  /prune/,
  /\$\(/,
  /`/,
  /&&/,
  /\|\|/,
  /;/,
  />/,
  /</,
  /2>&1/,
  /\|\s*sh/,
  /\|\s*bash/,
]

const MAX_COMMAND_LENGTH = 500

function validateDockerCommand(command) {
  if (!command || command.length > MAX_COMMAND_LENGTH) return null
  for (const pattern of BLOCKED_PATTERNS) {
    if (pattern.test(command)) return null
  }
  const normalized = command.trim().toLowerCase()
  let rest = normalized.startsWith('docker ') ? normalized.slice(7).trim() : normalized
  const parts = rest.split(/\s+/).filter(Boolean)
  const base = parts[0] || ''
  if (BLOCKED_COMMANDS.has(base)) return null
  // docker system df / docker container ls etc.
  if (base === 'system' && parts[1] && ['df', 'info', 'events'].includes(parts[1])) {
    return command.startsWith('docker ') ? command : `docker ${command}`
  }
  if (ALLOWED_DOCKER_COMMANDS.has(base) || base === 'help' || base === '--help' || base === '-h') {
    return command.startsWith('docker ') ? command : `docker ${command}`
  }
  return null
}

/**
 * @param {string} connectionId
 * @param {import('../client/connection.js').PearDockConnection} [peer]
 */
function startDockerTerminal(connectionId, peer) {
  const conn = peer || manager.active
  if (!conn?.connected) {
    console.error('[ERROR] No active peer for Docker CLI terminal.')
    return
  }

  if (dockerTerminalSession) {
    // Refocus existing
    dockerTerminalSession.xterm?.focus()
    dockerTerminalSession.fitController?.fitNow()
    return
  }

  const dockerTerminalContainer = document.getElementById('docker-terminal-container')
  const dockerTerminalTitle = document.getElementById('docker-terminal-title')
  const dockerTerminalModal = document.getElementById('dockerTerminalModal')
  const dockerKillTerminalBtn = document.getElementById('docker-kill-terminal-btn')

  if (!dockerTerminalContainer || !dockerTerminalModal) {
    console.error('[ERROR] Missing Docker CLI terminal DOM')
    return
  }

  const xterm = new Terminal(
    defaultXtermOptions({
      fontSize: dockerTerminalFontSize,
      theme: dockerTerminalThemes[dockerTerminalTheme] || dockerTerminalThemes.dark,
      convertEol: true,
    })
  )
  const fitAddon = new FitAddon()
  xterm.loadAddon(fitAddon)

  dockerTerminalContainer.innerHTML = ''
  dockerTerminalContainer.style.height = dockerTerminalContainer.style.height || '500px'
  xterm.open(dockerTerminalContainer)

  const fitController = createFitController(fitAddon, xterm, () => {
    // Docker CLI is line-mode; resize is cosmetic for local xterm only
  })
  fitController.observe(dockerTerminalContainer)

  const peerDataHandler = (response) => {
    try {
      if (!response || response.type !== 'dockerOutput') return
      if (response.connectionId && response.connectionId !== connectionId) return
      let text = decodePayload(response.data, response.encoding || 'utf8')
      // Ensure newlines render in convertEol mode
      if (text && !text.endsWith('\n') && !text.endsWith('\r')) {
        // keep as-is for partial chunks
      }
      xterm.write(text.replace(/\r?\n/g, '\r\n'))
    } catch (error) {
      console.error(`[ERROR] Failed to handle docker output: ${error.message}`)
    }
  }

  const managerHandler = (msg, c) => {
    if (c && conn && c !== conn && c.id !== conn.id) return
    peerDataHandler(msg)
  }
  conn.on?.('message', peerDataHandler)
  manager.on('message', managerHandler)

  let inputBuffer = ''
  const onDataDisposable = xterm.onData((input) => {
    // Enter
    if (input === '\r') {
      const line = inputBuffer.trim()
      inputBuffer = ''
      xterm.write('\r\n')
      if (!line) {
        xterm.write('\x1b[32m$\x1b[0m ')
        return
      }
      const fullCommand = validateDockerCommand(line)
      if (!fullCommand) {
        xterm.write('\x1b[31m[ERROR]\x1b[0m Invalid or blocked command.\r\n')
        xterm.write('Allowed: ps, images, logs, inspect, stats, system df, …\r\n')
        xterm.write('\x1b[32m$\x1b[0m ')
        return
      }
      const api = conn.request ? conn : manager
      api
        .request(Methods.dockerCommand, { connectionId, data: fullCommand })
        .then(() => {
          xterm.write('\x1b[32m$\x1b[0m ')
        })
        .catch((err) => {
          xterm.write(`\x1b[31m[ERROR]\x1b[0m ${err.message}\r\n`)
          xterm.write('\x1b[32m$\x1b[0m ')
        })
      return
    }
    // Backspace
    if (input === '\u007F' || input === '\b') {
      if (inputBuffer.length > 0) {
        inputBuffer = inputBuffer.slice(0, -1)
        xterm.write('\b \b')
      }
      return
    }
    // Ctrl+C
    if (input === '\u0003') {
      inputBuffer = ''
      xterm.write('^C\r\n\x1b[32m$\x1b[0m ')
      return
    }
    // Ctrl+U clear line
    if (input === '\u0015') {
      while (inputBuffer.length > 0) {
        inputBuffer = inputBuffer.slice(0, -1)
        xterm.write('\b \b')
      }
      return
    }
    // Ignore other controls except printable / tab
    if (input < ' ' && input !== '\t') return

    inputBuffer += input
    xterm.write(input)
  })

  dockerTerminalSession = {
    xterm,
    fitAddon,
    fitController,
    connectionId,
    peer: conn,
    peerDataHandler,
    managerHandler,
    onDataDisposable,
  }

  if (dockerTerminalTitle) {
    dockerTerminalTitle.textContent = `Docker CLI Terminal: ${connectionId}`
  }

  const modalInstance = bootstrap.Modal.getOrCreateInstance(dockerTerminalModal)
  dockerTerminalModal.addEventListener(
    'shown.bs.modal',
    () => {
      fitController.fitNow()
      xterm.focus()
      xterm.write('\x1b[1mDocker CLI\x1b[0m (read-only allow-list)\r\n\x1b[32m$\x1b[0m ')
    },
    { once: true }
  )
  dockerTerminalModal.addEventListener(
    'hidden.bs.modal',
    () => {
      cleanUpDockerTerminal()
    },
    { once: true }
  )
  modalInstance.show()

  if (dockerKillTerminalBtn) {
    dockerKillTerminalBtn.onclick = () => cleanUpDockerTerminal()
  }

  requestAnimationFrame(() => safeFit(fitAddon, xterm))
}

function cleanUpDockerTerminal() {
  const dockerTerminalContainer = document.getElementById('docker-terminal-container')
  const dockerTerminalModal = document.getElementById('dockerTerminalModal')

  if (dockerTerminalSession) {
    try {
      dockerTerminalSession.onDataDisposable?.dispose()
      dockerTerminalSession.fitController?.disconnect()
      dockerTerminalSession.peer?.removeListener?.('message', dockerTerminalSession.peerDataHandler)
      if (dockerTerminalSession.managerHandler) {
        manager.removeListener('message', dockerTerminalSession.managerHandler)
      }
      dockerTerminalSession.xterm?.dispose()
    } catch {
      // ignore
    }
    dockerTerminalSession = null
  }

  if (dockerTerminalContainer) dockerTerminalContainer.innerHTML = ''

  if (dockerTerminalModal) {
    const modalInstance = bootstrap.Modal.getInstance(dockerTerminalModal)
    modalInstance?.hide()
  }
  document.querySelector('.modal-backdrop')?.remove()
  document.body.classList.remove('modal-open')
  document.body.style.paddingRight = ''
}

function updateDockerTerminalFontSizeDisplay() {
  const display = document.getElementById('docker-terminal-font-size-display')
  if (display) display.textContent = String(dockerTerminalFontSize)
}

document.addEventListener('DOMContentLoaded', () => {
  const applySize = (n) => {
    dockerTerminalFontSize = n
    if (dockerTerminalSession?.xterm) {
      dockerTerminalSession.xterm.options.fontSize = n
      dockerTerminalSession.fitController?.fitNow()
    }
    updateDockerTerminalFontSizeDisplay()
  }
  document.getElementById('docker-terminal-font-decrease')?.addEventListener('click', () => {
    if (dockerTerminalFontSize > 8) applySize(dockerTerminalFontSize - 1)
  })
  document.getElementById('docker-terminal-font-increase')?.addEventListener('click', () => {
    if (dockerTerminalFontSize < 28) applySize(dockerTerminalFontSize + 1)
  })
  document.getElementById('docker-terminal-font-reset')?.addEventListener('click', () => applySize(14))
  document.getElementById('docker-terminal-copy-btn')?.addEventListener('click', () => {
    const sel = dockerTerminalSession?.xterm?.getSelection?.()
    if (sel) navigator.clipboard.writeText(sel).catch(() => {})
  })
  document.getElementById('docker-terminal-clear-btn')?.addEventListener('click', () => {
    dockerTerminalSession?.xterm?.clear()
  })
  const themeSelect = document.getElementById('docker-terminal-theme-select')
  try {
    const pref = window.__peardockSettings?.dockerTerminalTheme
    if (pref && dockerTerminalThemes[pref]) {
      dockerTerminalTheme = pref
    }
  } catch {
    // ignore
  }
  if (themeSelect) {
    themeSelect.value = dockerTerminalTheme
    themeSelect.addEventListener('change', (e) => {
      dockerTerminalTheme = e.target.value
      if (dockerTerminalSession?.xterm) {
        dockerTerminalSession.xterm.options.theme =
          dockerTerminalThemes[dockerTerminalTheme] || dockerTerminalThemes.dark
      }
    })
  }
  updateDockerTerminalFontSizeDisplay()
})

if (typeof window !== 'undefined') {
  const prev = window.__peardockApplyTerminalThemes
  window.__peardockApplyTerminalThemes = (termTheme, dockerTheme) => {
    if (typeof prev === 'function') prev(termTheme, dockerTheme)
    if (dockerTheme && dockerTerminalThemes[dockerTheme]) {
      dockerTerminalTheme = dockerTheme
      if (dockerTerminalSession?.xterm) {
        dockerTerminalSession.xterm.options.theme =
          dockerTerminalThemes[dockerTerminalTheme] || dockerTerminalThemes.dark
      }
      const themeSelect = document.getElementById('docker-terminal-theme-select')
      if (themeSelect) themeSelect.value = dockerTheme
    }
  }
}

export { startDockerTerminal, cleanUpDockerTerminal, dockerTerminalSession }