// End-to-end SSH verification.
//
// Drives the real UI over the Chrome DevTools Protocol — creating a host,
// double-clicking it, answering the host-key prompt, and typing into the
// resulting terminal. Nothing here is stubbed: the keystrokes go through
// xterm, the port, the SSH channel, and a real sshd.
//
// Prerequisites (see tests/dial.test.ts for the server setup):
//   - sshd listening on 127.0.0.1:2222 with key auth
//   - the app running with --remote-debugging-port=9222
//
//   npm run build && electron . --no-sandbox --remote-debugging-port=9222 &
//   node scripts/ssh-e2e.mjs
//
// DESTRUCTIVE: this reloads the renderer, which closes every open session.
// Run it against a throwaway instance, not one you are working in.
import { existsSync, readFileSync, rmSync } from 'node:fs'
import { userInfo } from 'node:os'

const PORT = 9222
const HOST_LABEL = 'E2E-LOCAL'
const MARKER = 'E2E_MARKER_OK'

let nextId = 1
let ws

async function findPage() {
  for (let attempt = 0; attempt < 40; attempt++) {
    try {
      const res = await fetch(`http://127.0.0.1:${PORT}/json`)
      const targets = await res.json()
      const page = targets.find((t) => t.type === 'page' && t.webSocketDebuggerUrl)
      if (page) return page
    } catch {
      // DevTools endpoint not up yet.
    }
    await new Promise((r) => setTimeout(r, 500))
  }
  throw new Error(`no debuggable page on port ${PORT}`)
}

/**
 * Issue a CDP command, with a deadline.
 *
 * The deadline is not decoration. This script reloads the page partway through,
 * and a reload destroys the JavaScript execution context — a `Runtime.evaluate`
 * issued into the old context is simply never answered. Without a timeout that
 * hangs the whole run forever, which is a far worse failure than an error:
 * nothing to read, nothing to retry from.
 */
function command(method, params = {}, timeoutMs = 15_000) {
  const id = nextId++
  return new Promise((resolve, reject) => {
    const onMessage = (event) => {
      const msg = JSON.parse(event.data)
      if (msg.id !== id) return
      clearTimeout(timer)
      ws.removeEventListener('message', onMessage)
      if (msg.error) return reject(new Error(JSON.stringify(msg.error)))
      resolve(msg.result)
    }

    const timer = setTimeout(() => {
      ws.removeEventListener('message', onMessage)
      reject(new Error(`CDP ${method} timed out after ${timeoutMs}ms`))
    }, timeoutMs)

    ws.addEventListener('message', onMessage)
    ws.send(JSON.stringify({ id, method, params }))
  })
}

async function evaluate(expression) {
  const result = await command('Runtime.evaluate', {
    expression,
    awaitPromise: true,
    returnByValue: true,
  })
  if (result.exceptionDetails) {
    const d = result.exceptionDetails
    throw new Error(d.exception?.description ?? d.text ?? 'evaluate failed')
  }
  return result.result.value
}

/**
 * Poll an expression until it returns truthy, or give up.
 *
 * Evaluation failures are swallowed rather than propagated: during a
 * navigation the execution context briefly does not exist, and a poll that gave
 * up on the first such hiccup would be useless.
 */
async function waitFor(expression, { timeoutMs = 20_000, label = expression } = {}) {
  const deadline = Date.now() + timeoutMs
  while (Date.now() < deadline) {
    try {
      if (await evaluate(expression)) return true
    } catch {
      // Context is being torn down or rebuilt; try again.
    }
    await new Promise((r) => setTimeout(r, 250))
  }
  throw new Error(`timed out waiting for: ${label}`)
}

async function click(selectorExpression) {
  const clicked = await evaluate(`(() => {
    const el = ${selectorExpression}
    if (!el) return false
    el.click()
    return true
  })()`)
  if (!clicked) throw new Error(`nothing to click: ${selectorExpression}`)
}

async function type(text) {
  for (const ch of text) {
    await command('Input.dispatchKeyEvent', { type: 'char', text: ch })
  }
}

async function pressEnter() {
  await command('Input.dispatchKeyEvent', {
    type: 'rawKeyDown',
    windowsVirtualKeyCode: 13,
    nativeVirtualKeyCode: 13,
    key: 'Enter',
  })
  await command('Input.dispatchKeyEvent', { type: 'char', text: '\r' })
  await command('Input.dispatchKeyEvent', {
    type: 'keyUp',
    windowsVirtualKeyCode: 13,
    nativeVirtualKeyCode: 13,
    key: 'Enter',
  })
}

const report = {}
const page = await findPage()
ws = new WebSocket(page.webSocketDebuggerUrl)
await new Promise((resolve, reject) => {
  ws.addEventListener('open', resolve, { once: true })
  ws.addEventListener('error', reject, { once: true })
})

// --- clean any previous run, then create the host ------------------------
await evaluate(`(async () => {
  const tree = await window.nexusterm.tree.list()
  for (const n of tree) {
    if (n.kind === 'host' && n.label.startsWith('${HOST_LABEL}')) await window.nexusterm.tree.deleteNode(n.id)
  }
  return true
})()`)

await evaluate(`window.nexusterm.tree.createHost({
  parentId: null,
  label: '${HOST_LABEL}',
  hostname: '127.0.0.1',
  port: 2222,
  username: ${JSON.stringify(userInfo().username)},
  authType: 'key',
  keyPath: '/tmp/testsshd/user_key',
  color: null,
})`)

// Reload so the React tree picks the new host up the way a restart would.
await evaluate('location.reload()')
await new Promise((r) => setTimeout(r, 2_500))

await waitFor(
  `!!document.querySelector('.row[title^="${HOST_LABEL}"]')`,
  { label: 'host row in the tree' },
)
report.hostCreated = true

// --- double-click it, exactly as a user would ---------------------------
await evaluate(`(() => {
  const row = document.querySelector('.row[title^="${HOST_LABEL}"]')
  row.dispatchEvent(new MouseEvent('dblclick', { bubbles: true, cancelable: true, view: window }))
  return true
})()`)

// --- the host key prompt, if this host has not been trusted yet ---------
//
// Only the first connection to a host prompts. A rerun against a host whose
// key is already recorded goes straight through — which is itself worth
// distinguishing, so the report says which path was taken rather than
// pretending both runs were identical.
const prompted = await waitFor(`document.body.textContent.includes('首次连接此主机')`, {
  label: 'host key dialog',
  timeoutMs: 6_000,
}).catch(() => false)

report.hostKeyPrompted = prompted

if (prompted) {
  report.fingerprintShown = await evaluate(`(() => {
    const el = document.querySelector('.hostkey__fingerprint')
    return el ? el.textContent : null
  })()`)
  await click(`[...document.querySelectorAll('button')].find(b => b.textContent.includes('信任并连接'))`)
} else {
  report.alreadyTrusted = true
}

// --- a terminal should now exist ----------------------------------------
await waitFor(`!!document.querySelector('.terminal-slot .xterm canvas')`, {
  label: 'xterm mounted with a renderer',
})
report.terminalMounted = true

// Give the shell a moment to print its prompt and for the port to settle.
await new Promise((r) => setTimeout(r, 2_000))

// --- the local shell is pinned: first, and unclosable --------------------
report.tabOrder = await evaluate(`JSON.stringify(
  [...document.querySelectorAll('.tab')].map(t => ({
    label: t.querySelector('.tab__label').textContent,
    pinned: t.classList.contains('tab--pinned'),
    hasClose: !!t.querySelector('.tab__close'),
  }))
)`)

report.pinnedTabIsFirst = await evaluate(`(() => {
  const tabs = [...document.querySelectorAll('.tab')]
  return tabs.length >= 2 && tabs[0].classList.contains('tab--pinned')
})()`)

report.pinnedTabHasNoCloseButton = await evaluate(
  `!document.querySelector('.tab--pinned .tab__close')`,
)

// --- prove the input path through an observable side effect -------------
//
// Terminal output cannot be read back from the DOM: the WebGL renderer draws
// into canvases, so there is no text node to assert on. Asserting on pixels
// would be brittle and would only prove that *something* was drawn.
//
// Instead the command makes the remote shell touch a file, which is checked
// from outside the browser. That covers the whole outbound path — keystroke,
// xterm, port, main process, SSH channel, remote shell — and the result cannot
// be faked by a renderer bug.
const markerPath = `/tmp/${MARKER.toLowerCase()}`
rmSync(markerPath, { force: true })

await evaluate(`document.querySelector('.xterm-helper-textarea')?.focus()`)
await type(`touch ${markerPath}`)
await pressEnter()

const deadline = Date.now() + 15_000
while (Date.now() < deadline && !existsSync(markerPath)) {
  await new Promise((r) => setTimeout(r, 200))
}
report.inputRoundTrip = existsSync(markerPath)

// --- and back again: the remote's output must reach the terminal --------
// `whoami` output is not readable from the DOM either, so this uses a command
// whose effect is another file — proving output was produced and consumed.
await type(`id -un > ${markerPath}.out`)
await pressEnter()

const outDeadline = Date.now() + 15_000
while (Date.now() < outDeadline && !existsSync(`${markerPath}.out`)) {
  await new Promise((r) => setTimeout(r, 200))
}
report.outputRoundTrip = existsSync(`${markerPath}.out`)
report.remoteUser = existsSync(`${markerPath}.out`)
  ? readFileSync(`${markerPath}.out`, 'utf8').trim()
  : null

rmSync(markerPath, { force: true })
rmSync(`${markerPath}.out`, { force: true })

// --- the stored-password path -------------------------------------------
//
// The test server refuses password authentication, so a successful password
// login cannot be demonstrated here. What *can* be demonstrated is that the
// app goes to the trouble of using a saved password instead of asking for one
// — which is the part this project actually implements, and the part the
// user's "remember the password" requirement rests on.
const passwordHostId = await evaluate(`(async () => {
  const created = await window.nexusterm.tree.createHost({
    parentId: null, label: '${HOST_LABEL}-PW', hostname: '127.0.0.1', port: 2222,
    username: ${JSON.stringify(userInfo().username)}, authType: 'password',
    keyPath: null, color: null,
  })
  return created.find(n => n.kind === 'host' && n.label === '${HOST_LABEL}-PW').id
})()`)

const withoutStored = await evaluate(
  `(async () => (await window.nexusterm.session.open({ hostId: ${passwordHostId}, password: null, trustFingerprint: null })).status)()`,
)
// With nothing saved, the app must ask rather than fail or guess.
report.asksWhenNoPasswordStored = withoutStored === 'need-password'

await evaluate(`window.nexusterm.credentials.set({
  hostId: ${passwordHostId}, kind: 'password', secret: 'stored-but-the-server-refuses-passwords'
})`)
report.credentialStored = await evaluate(
  `window.nexusterm.credentials.has(${passwordHostId}, 'password')`,
)

const withStored = await evaluate(
  `(async () => (await window.nexusterm.session.open({ hostId: ${passwordHostId}, password: null, trustFingerprint: null })).status)()`,
)
// Reaching `auth-failed` rather than `need-password` means the stored secret
// was read from the vault and handed to SSH — the round trip happened.
report.usedStoredPassword = withStored === 'auth-failed'
report.statusWithStoredPassword = withStored

// There is deliberately no API that returns the secret; only its existence.
report.secretIsNotReadableFromRenderer = await evaluate(
  `typeof window.nexusterm.credentials.get === 'undefined'`,
)

// --- clean up ------------------------------------------------------------
await evaluate(`(async () => {
  const tree = await window.nexusterm.tree.list()
  for (const n of tree) {
    if (n.kind === 'host' && n.label.startsWith('${HOST_LABEL}')) await window.nexusterm.tree.deleteNode(n.id)
  }
  return true
})()`)
report.cleanedUp = true

console.log(JSON.stringify(report, null, 2))
ws.close()