/**
 * test/desktop/server-config.test.ts — unit tests for buildServerEnv (B1).
 *
 * Covers the PORT / BIND_HOST / SHELL_PATH / USE_TMUX mapping, the immutability
 * guarantee (input.env untouched), and pass-through of unrelated env vars.
 */

import { execFileSync } from 'node:child_process'

import { describe, test, expect } from 'vitest'
import { buildServerEnv } from '../../desktop/src/server-config.js'
import { loadConfig } from '../../src/config.js'
import type { DesktopPrefs } from '../../desktop/src/types.js'

const tmuxInstalled = (() => {
  try {
    execFileSync('tmux', ['-V'], { stdio: 'ignore' })
    return true
  } catch {
    return false
  }
})()

const BASE_PREFS: DesktopPrefs = {
  port: null,
  lanSharing: false,
  shellPath: null,
  openAtLogin: false,
  notifyOnApproval: true,
  notifyOnStatusChange: true,
}

describe('buildServerEnv', () => {
  test('sets PORT to the stringified port', () => {
    const result = buildServerEnv({ prefs: BASE_PREFS, port: 4321, platform: 'darwin', env: {} })
    expect(result.PORT).toBe('4321')
  })

  test('binds 127.0.0.1 when lanSharing is off', () => {
    const result = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'darwin', env: {} })
    expect(result.BIND_HOST).toBe('127.0.0.1')
  })

  test('binds 0.0.0.0 when lanSharing is on', () => {
    // Arrange
    const prefs = { ...BASE_PREFS, lanSharing: true }

    // Act
    const result = buildServerEnv({ prefs, port: 3000, platform: 'darwin', env: {} })

    // Assert
    expect(result.BIND_HOST).toBe('0.0.0.0')
  })

  test('uses prefs.shellPath as SHELL_PATH when provided (overriding the platform default)', () => {
    // Arrange
    const prefs = { ...BASE_PREFS, shellPath: '/usr/bin/fish' }

    // Act
    const result = buildServerEnv({ prefs, port: 3000, platform: 'darwin', env: { SHELL: '/bin/zsh' } })

    // Assert
    expect(result.SHELL_PATH).toBe('/usr/bin/fish')
  })

  test('falls back to the platform default SHELL_PATH when prefs.shellPath is null', () => {
    const win = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'win32', env: {} })
    expect(win.SHELL_PATH).toBe('powershell.exe')

    const mac = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'darwin', env: { SHELL: '/bin/zsh' } })
    expect(mac.SHELL_PATH).toBe('/bin/zsh')
  })

  test('forces USE_TMUX off on win32 even when the ambient env enables it', () => {
    const result = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'win32', env: { USE_TMUX: '1' } })
    expect(result.USE_TMUX).toBe('0')
  })

  test('passes ambient USE_TMUX through on non-Windows platforms', () => {
    const result = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'linux', env: { USE_TMUX: '1' } })
    expect(result.USE_TMUX).toBe('1')
  })

  test('defaults USE_TMUX to auto-detect on non-Windows when the env is unset', () => {
    // Not '0'. Without tmux the shell is a direct child of the embedded server, so
    // quitting the app kills every session — which defeats the point of walking away
    // from a task and reconnecting later. 'auto' means "use tmux if it is installed".
    const result = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'linux', env: {} })
    expect(result.USE_TMUX).toBe('auto')
  })

  test('an explicit ambient USE_TMUX=0 still wins — opting out stays possible', () => {
    const result = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'darwin', env: { USE_TMUX: '0' } })
    expect(result.USE_TMUX).toBe('0')
  })

  // The bug this guards against was the two layers disagreeing: buildServerEnv emitted
  // a value that loadConfig then resolved to something else than intended. Assert the
  // end-to-end result, not just the string.
  test('the default resolves to tmux ON once loadConfig sees it', () => {
    if (!tmuxInstalled) return // 'auto' correctly resolves to false without the binary
    const env = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'darwin', env: {} })
    expect(loadConfig({ ...env, BIND_HOST: '127.0.0.1' }).useTmux).toBe(true)
  })

  test('an explicit opt-out resolves to tmux OFF through loadConfig', () => {
    const env = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'darwin', env: { USE_TMUX: '0' } })
    expect(loadConfig({ ...env, BIND_HOST: '127.0.0.1' }).useTmux).toBe(false)
  })

  test('does not mutate the input env', () => {
    // Arrange
    const env = { PATH: '/usr/bin', USE_TMUX: '1' }
    const snapshot = { ...env }

    // Act
    buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'win32', env })

    // Assert
    expect(env).toEqual(snapshot)
  })

  test('preserves unrelated ambient env vars', () => {
    // Arrange
    const env = { PATH: '/usr/bin', HOME: '/Users/me', CUSTOM: 'x' }

    // Act
    const result = buildServerEnv({ prefs: BASE_PREFS, port: 3000, platform: 'darwin', env })

    // Assert
    expect(result.PATH).toBe('/usr/bin')
    expect(result.HOME).toBe('/Users/me')
    expect(result.CUSTOM).toBe('x')
  })
})