package cmd

import (
	"errors"
	"os"
	"runtime"
	"strings"
	"testing"

	"github.com/warrenronsiek/ctask/internal/shell"
)

// withTTYCheck swaps the package-level isTTYCheck for the duration of the
// test. Tests that exercise refusal paths must NOT run in parallel — they
// mutate a package global.
func withTTYCheck(t *testing.T, fn func() bool) {
	t.Helper()
	orig := isTTYCheck
	isTTYCheck = fn
	t.Cleanup(func() { isTTYCheck = orig })
}

func TestPreflightRefusesNativeWindows(t *testing.T) {
	if runtime.GOOS != "windows" {
		t.Skip("native-Windows refusal applies only on Windows")
	}
	had := os.Getenv("WSL_DISTRO_NAME")
	os.Unsetenv("WSL_DISTRO_NAME")
	t.Cleanup(func() {
		if had != "" {
			os.Setenv("WSL_DISTRO_NAME", had)
		}
	})
	_, err := preflightPersistentEntry("resume")
	if err == nil {
		t.Fatal("expected refusal on native Windows")
	}
	if !strings.Contains(err.Error(), "tmux") || !strings.Contains(err.Error(), "WSL") {
		t.Errorf("expected tmux+WSL message: %v", err)
	}
}

func TestPreflightRefusesNestedTmux(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("nested-tmux check runs on Unix paths only in this test")
	}
	withTTYCheck(t, func() bool { return true })
	os.Setenv("TMUX", "/tmp/tmux-1000/default,1234,0")
	t.Cleanup(func() { os.Unsetenv("TMUX") })
	_, err := preflightPersistentEntry("resume")
	if err == nil {
		t.Fatal("expected refusal when $TMUX is set")
	}
	if !strings.Contains(err.Error(), "already inside tmux") {
		t.Errorf("expected nested-tmux message: %v", err)
	}
}

func TestPreflightRefusesNonTTY(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("focus this case on Unix; Windows TTY semantics covered by manual smoke")
	}
	os.Unsetenv("TMUX")
	withTTYCheck(t, func() bool { return false })
	_, err := preflightPersistentEntry("resume")
	if err == nil {
		t.Fatal("expected refusal when not a TTY")
	}
	if !strings.Contains(err.Error(), "interactive terminal") {
		t.Errorf("expected interactive-terminal message: %v", err)
	}
	if !strings.Contains(err.Error(), "ssh -t") {
		t.Errorf("error should mention ssh -t: %v", err)
	}
	if !strings.Contains(err.Error(), "ctask resume") {
		t.Errorf("error should mention command-specific bypass: %v", err)
	}
}

func TestPreflightCommandNameRendersInHints(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("path-based check covered on Unix")
	}
	os.Unsetenv("TMUX")
	withTTYCheck(t, func() bool { return false })
	_, err := preflightPersistentEntry("attach")
	if err == nil || !strings.Contains(err.Error(), "ctask attach") {
		t.Errorf("commandName must appear in hint: %v", err)
	}
}

func TestPreflightTmuxNotFound(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("PATH manipulation applies on Unix here")
	}
	os.Unsetenv("TMUX")
	withTTYCheck(t, func() bool { return true })
	orig := os.Getenv("PATH")
	t.Cleanup(func() { os.Setenv("PATH", orig) })
	os.Setenv("PATH", "")
	_, err := preflightPersistentEntry("resume")
	if err == nil {
		t.Fatal("expected refusal when tmux missing")
	}
	if !strings.Contains(err.Error(), "tmux is not installed") {
		t.Errorf("expected install-hint message: %v", err)
	}
}

// Confirm the helper returns the validated tmux path on the happy path so
// callers can pass it through LaunchOpts.TmuxPath without re-resolving.
func TestPreflightSuccessReturnsTmuxPath(t *testing.T) {
	if _, _, err := shell.LookupTmux(); err != nil {
		if errors.Is(err, shell.ErrTmuxNotFound) || errors.Is(err, shell.ErrTmuxTooOld) {
			t.Skip("tmux not adequate on this host")
		}
	}
	if runtime.GOOS == "windows" {
		t.Skip("happy-path test on WSL/Linux only")
	}
	os.Unsetenv("TMUX")
	withTTYCheck(t, func() bool { return true })
	tmuxPath, err := preflightPersistentEntry("resume")
	if err != nil {
		t.Fatalf("expected success, got %v", err)
	}
	if tmuxPath == "" {
		t.Error("expected non-empty tmuxPath on success")
	}
}