// Fenrir console screen reader.
// Copyright (c) 2026 Storm Dragon
// SPDX-License-Identifier: GPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation, either version 3 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along with
// this program. If not, see <https://www.gnu.org/licenses/gpl-3.0.html>.

//go:build linux && cgo

package terminal

import (
	"errors"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"syscall"
	"testing"
	"time"

	"git.stormux.org/storm/fenrir/internal/command"
	"git.stormux.org/storm/fenrir/internal/reader"
)

// Uses an isolated local mailbox and no personal/system mutt configuration.
// This verifies the actual application's terminal output, not audible speech.
func TestMuttCursorNavigation(t *testing.T) {
	if os.Getenv("FENRIR_MUTT_TEST") != "1" {
		t.Skip("set FENRIR_MUTT_TEST=1 to exercise installed mutt with a private mailbox")
	}
	for _, mode := range []string{"cursor", "highlight"} {
		t.Run(mode, func(t *testing.T) { test_mutt_navigation(t, mode) })
	}
}

func test_mutt_navigation(t *testing.T, mode string) {
	program, err := exec.LookPath("mutt")
	if err != nil {
		t.Fatal(err)
	}
	root := t.TempDir()
	if err := os.Mkdir(filepath.Join(root, "Mail"), 0700); err != nil {
		t.Fatal(err)
	}
	mailbox := filepath.Join(root, "mailbox")
	var messages strings.Builder
	for index := 1; index <= 30; index++ {
		fmt.Fprintf(&messages, "From sender@example.invalid Mon Jan  1 00:00:00 2024\nFrom: Sender <sender@example.invalid>\nTo: Username <recipient@example.invalid>\nDate: Mon, 1 Jan 2024 00:%02d:00 +0000\nSubject: Fixture message %02d\nMessage-ID: <fixture-%d@example.invalid>\n\nBody %d\n\n", index, index, index, index)
	}
	if err := os.WriteFile(mailbox, []byte(messages.String()), 0600); err != nil {
		t.Fatal(err)
	}
	master, slave, err := open_pty(12, 80)
	if err != nil {
		t.Fatal(err)
	}
	defer syscall.Close(master)
	slaveFile := os.NewFile(uintptr(slave), "mutt-pty")
	defer slaveFile.Close()
	child := exec.Command(program, "-n", "-F", "/dev/null", "-R", "-f", mailbox,
		"-e", "set sort=date; set arrow_cursor=no; set index_format='%4C %s'; set timeout=60")
	child.Env = []string{"HOME=" + root, "TERM=xterm-256color", "LC_ALL=C", "PATH=/usr/bin:/bin"}
	child.Stdin, child.Stdout, child.Stderr = slaveFile, slaveFile, slaveFile
	child.SysProcAttr = &syscall.SysProcAttr{Setsid: true, Setctty: true, Ctty: 0}
	if err := child.Start(); err != nil {
		t.Fatal(err)
	}
	defer func() { child.Process.Kill(); child.Wait() }()
	if err := syscall.SetNonblock(master, true); err != nil {
		t.Fatal(err)
	}
	emulator, err := new_emulator(12, 80)
	if err != nil {
		t.Fatal(err)
	}
	defer emulator.close()
	drain := func() {
		t.Helper()
		deadline := time.Now().Add(3 * time.Second)
		quietAt := time.Now()
		var buffer [32768]byte
		for time.Now().Before(deadline) {
			count, err := syscall.Read(master, buffer[:])
			if count > 0 {
				emulator.feed(buffer[:count])
				quietAt = time.Now()
			} else if err != nil && !errors.Is(err, syscall.EAGAIN) {
				t.Fatal(err)
			} else if time.Since(quietAt) > 150*time.Millisecond {
				return
			}
			time.Sleep(5 * time.Millisecond)
		}
		t.Fatal("mutt did not settle")
	}
	drain()
	initial := emulator.snapshot(true, false)
	if !strings.Contains(string(string(initial.Cells)), "Fixture message 01") {
		t.Fatalf("mailbox did not open: %q", string(initial.Cells))
	}
	engine := reader.New()
	engine.Configure_tracking(mode)
	engine.Update(initial)
	var selections []int
	for index := 2; index <= 15; index++ {
		selections = append(selections, index)
	}
	for index := 14; index >= 1; index-- {
		selections = append(selections, index)
	}
	previousIndex := 1
	for _, index := range selections {
		// Reviewing a message must not suppress the next application arrow.
		engine.Command(command.CurrentLine)
		engine.Note_input(true, false, false)
		arrow := "\x1bOB" // ncurses enables application cursor keys
		if index < previousIndex {
			arrow = "\x1bOA"
		}
		if _, err := syscall.Write(master, []byte(arrow)); err != nil {
			t.Fatal(err)
		}
		drain()
		next := emulator.snapshot(true, false)
		output := engine.Update(next)
		var spoken strings.Builder
		for _, message := range output {
			spoken.WriteString(message.Text)
		}
		if !strings.Contains(spoken.String(), fmt.Sprintf("Fixture message %02d", index)) {
			t.Fatalf("selection %d cursor (%d,%d) -> (%d,%d): output %v", index, initial.X, initial.Y, next.X, next.Y, output)
		}
		initial = next
		previousIndex = index
	}
}