// Bubble Tea comes from cli/third_party, patched so that a command run with
// tea.Exec (the prompt editor, ssh sign-in) hands its result to the model
// before any key read once the terminal is back (see
// third_party/bubbletea.patch). Upstream sends that result from a goroutine,
// so a key typed as the editor closes could reach the chat first and act on
// the draft from before the edit: ctrl+g then reopened the editor on the old
// text. E2E drives a real terminal but meets this race only now and then.
package tui

import (
	"io"
	"os"
	"testing"
	"time"

	tea "charm.land/bubbletea/v2"
)

// typeAsItExits stands in for an editor the person leaves by typing on: its
// last act writes a key to the terminal input.
type typeAsItExits struct{ input *os.File }

func (c typeAsItExits) Run() error {
	_, err := c.input.WriteString("x")
	return err
}
func (typeAsItExits) SetStdin(io.Reader)  {}
func (typeAsItExits) SetStdout(io.Writer) {}
func (typeAsItExits) SetStderr(io.Writer) {}

type execDoneMsg struct{}

type execOrderModel struct {
	input *os.File
	seen  []string
}

func (m execOrderModel) Init() tea.Cmd {
	return tea.Exec(typeAsItExits{m.input}, func(error) tea.Msg { return execDoneMsg{} })
}

func (m execOrderModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case execDoneMsg:
		m.seen = append(m.seen, "exec")
	case tea.KeyPressMsg:
		m.seen = append(m.seen, msg.String())
	}
	if len(m.seen) == 2 {
		return m, tea.Quit
	}
	return m, nil
}

func (execOrderModel) View() tea.View { return tea.NewView("") }

func TestExecResultArrivesBeforeKeysTypedAsItEnds(t *testing.T) {
	read, write, err := os.Pipe()
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { read.Close(); write.Close() })
	program := tea.NewProgram(execOrderModel{input: write}, tea.WithInput(read), tea.WithOutput(io.Discard))
	done := make(chan tea.Model, 1)
	go func() {
		final, err := program.Run()
		if err != nil {
			t.Error(err)
		}
		done <- final
	}()
	select {
	case final := <-done:
		if seen := final.(execOrderModel).seen; len(seen) != 2 || seen[0] != "exec" || seen[1] != "x" {
			t.Fatalf("the model saw %v, want the exec result before the key", seen)
		}
	case <-time.After(10 * time.Second):
		program.Kill()
		t.Fatal("the program never saw both the exec result and the key")
	}
}