TermlessHeadless terminal testing

import { test, expect } from "vitest"
import { createTestTerminal } from "@termless/test"

// ANSI helpers — real apps use @silvery/ag-term or @silvery/ansi, these are just for test data
const BOLD = (s: string) => `\x1b[1m${s}\x1b[0m`
const GREEN = (s: string) => `\x1b[38;2;0;255;0m${s}\x1b[0m`

test("inspect what string matching can't see", () => {
  // Creates an xterm.js terminal by default. Ghostty, Alacritty, WezTerm, vt100,
  // and Peekaboo backends are also available — see Multi-Backend Testing below.
  const term = createTestTerminal({ cols: 40, rows: 3 })

  // Simulate a build pipeline — 4 lines overflow a 3-row terminal
  term.feed("Step 1: install\r\n")
  term.feed(`Step 2: ${GREEN("build ok")}\r\n`)
  term.feed(`Step 3: ${BOLD("test")}\r\n`)
  term.feed("Step 4: deploy")

  // Region selectors — screen, scrollback, buffer
  expect(term.scrollback).toContainText("install") // scrolled off, still in history
  expect(term.screen).toContainText("deploy") // visible area
  expect(term.buffer).toContainText("install") // everything (scrollback + screen)
  expect(term.row(0)).toHaveText("Step 2: build ok") // specific row

  // Cell styles — colors that getText() can't see
  expect(term.cell(0, 8)).toHaveFg("#00ff00") // "build ok" is green
  expect(term.cell(1, 8)).toBeBold() // "test" is bold

  // Scroll up, then assert on viewport
  term.backend.scrollViewport(1)
  expect(term.viewport).toContainText("install")

  // Resize — verify content survives
  term.resize(20, 3)
  expect(term.screen).toContainText("deploy")

  // Terminal state — window title, cursor, modes
  term.feed("\x1b]2;Build Pipeline\x07") // OSC 2 — set window title
  expect(term).toHaveTitle("Build Pipeline")
  expect(term).toHaveCursorAt(14, 2) // after "Step 4: deploy"
  expect(term).toBeInMode("autoWrap") // default mode
  expect(term).not.toBeInMode("altScreen") // not in alternate screen
})

// Instead of fragile string matching...
expect(output).toContain("\x1b[1;31mError\x1b[0m")

// ...assert on terminal state
expect(term.screen).toContainText("Error")
expect(term.cell(0, 0)).toBeBold()
expect(term.cell(0, 0)).toHaveFg("#ff0000")
expect(term).toBeInMode("altScreen")
expect(term).toHaveTitle("my-app")

// 1. Factory function (explicit, sync)
import { createXtermBackend } from "@termless/xtermjs"
const term = createTerminal({ backend: createXtermBackend() })

// 2. String name via registry (async — handles WASM/native init)
import { backend } from "@termless/core"
const b = await backend("ghostty")
const term = createTerminal({ backend: b })