package runner

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

	"github.com/kotoyuuko/cc-switch-cli/internal/config"
)

// makeExec writes an executable script at dir/name and returns its path.
func makeExec(t *testing.T, dir, name, body string) string {
	t.Helper()
	p := filepath.Join(dir, name)
	if err := os.WriteFile(p, []byte(body), 0o755); err != nil {
		t.Fatal(err)
	}
	return p
}

func TestResolveClaudePath_FromConfig(t *testing.T) {
	dir := t.TempDir()
	p := makeExec(t, dir, "claude", "#!/bin/sh\nexit 0\n")
	got, err := ResolveClaudePath(config.Config{ClaudePath: p})
	if err != nil {
		t.Fatalf("unexpected: %v", err)
	}
	if got != p {
		t.Errorf("got %q want %q", got, p)
	}
}

func TestResolveClaudePath_FromPATH(t *testing.T) {
	dir := t.TempDir()
	_ = makeExec(t, dir, "claude", "#!/bin/sh\nexit 0\n")
	t.Setenv("PATH", dir)
	got, err := ResolveClaudePath(config.Config{})
	if err != nil {
		t.Fatalf("unexpected: %v", err)
	}
	// LookPath may return a symlink-resolved form; just check it matches.
	if !strings.HasSuffix(got, "/claude") {
		t.Errorf("unexpected path: %q", got)
	}
}

func TestResolveClaudePath_NotFound(t *testing.T) {
	t.Setenv("PATH", t.TempDir()) // empty dir on PATH
	_, err := ResolveClaudePath(config.Config{})
	if err == nil {
		t.Fatal("expected error")
	}
	if !strings.Contains(err.Error(), "config set claude-path") {
		t.Errorf("missing hint: %v", err)
	}
}

func TestResolveClaudePath_NonExecutable(t *testing.T) {
	dir := t.TempDir()
	p := filepath.Join(dir, "claude")
	if err := os.WriteFile(p, []byte(""), 0o644); err != nil {
		t.Fatal(err)
	}
	_, err := ResolveClaudePath(config.Config{ClaudePath: p})
	if err == nil {
		t.Fatal("expected non-executable error")
	}
}

func TestRun_EnvInjected(t *testing.T) {
	dir := t.TempDir()
	out := filepath.Join(dir, "out")
	// Capture FOO's value to a file and exit 0.
	script := makeExec(t, dir, "test", "#!/bin/sh\nprintf '%s' \"$FOO\" > "+out+"\nexit 0\n")

	code, err := Run(script, []string{"FOO=bar", "PATH=/usr/bin"}, nil)
	if err != nil {
		t.Fatalf("Run: %v", err)
	}
	if code != 0 {
		t.Errorf("exit code = %d", code)
	}
	b, err := os.ReadFile(out)
	if err != nil {
		t.Fatal(err)
	}
	if string(b) != "bar" {
		t.Errorf("FOO not injected: %q", string(b))
	}
}

func TestRun_ExitCodePassthrough(t *testing.T) {
	dir := t.TempDir()
	script := makeExec(t, dir, "test", "#!/bin/sh\nexit 42\n")
	code, err := Run(script, nil, nil)
	if err != nil {
		t.Fatalf("Run: %v", err)
	}
	if code != 42 {
		t.Errorf("exit code = %d, want 42", code)
	}
}

func TestRun_SignalForwarding(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("signal forwarding is Unix-only")
	}

	dir := t.TempDir()
	// Child traps INT, exits with 130 (128+2).
	script := makeExec(t, dir, "trapper", "#!/bin/sh\ntrap 'exit 130' INT\nsleep 5\n")

	// Use a goroutine to launch Run, then send SIGINT to our own pid (Run
	// installs the handler which forwards it to the child).
	type result struct {
		code int
		err  error
	}
	done := make(chan result, 1)
	go func() {
		c, e := Run(script, nil, nil)
		done <- result{c, e}
	}()

	// Give the child a moment to install its trap.
	time.Sleep(200 * time.Millisecond)
	if err := syscall.Kill(os.Getpid(), syscall.SIGINT); err != nil {
		t.Fatal(err)
	}

	select {
	case r := <-done:
		if r.err != nil {
			t.Fatalf("Run: %v", r.err)
		}
		if r.code != 130 {
			t.Errorf("exit code = %d, want 130", r.code)
		}
	case <-time.After(3 * time.Second):
		t.Fatal("timed out waiting for child to exit")
	}
}

func TestRun_SignalKill_128Plus(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("Unix-only")
	}
	// Child that ignores nothing and just sleeps; we kill it with SIGKILL
	// directly to avoid the signal-forwarding path (which would route via the
	// current process first).
	dir := t.TempDir()
	script := makeExec(t, dir, "sleeper", "#!/bin/sh\nsleep 3\n")

	cmd := exec.Command(script)
	if err := cmd.Start(); err != nil {
		t.Fatal(err)
	}
	go func() {
		time.Sleep(100 * time.Millisecond)
		_ = cmd.Process.Signal(syscall.SIGKILL)
	}()
	code, _ := asExitError(cmd.Wait())
	if code != 128+int(syscall.SIGKILL) {
		t.Errorf("exit code = %d, want %d", code, 128+int(syscall.SIGKILL))
	}
}