package gitcmd

import (
	"context"
	"os"
	"os/exec"
	"strings"
	"testing"
)

func getEnvValue(envs []string, key string) (string, bool) {
	prefix := key + "="
	for _, e := range envs {
		if v, ok := strings.CutPrefix(e, prefix); ok {
			return v, true
		}
	}
	return "", false
}

func TestHomeDir(t *testing.T) {

	t.Setenv("GIT_HOME", "/custom/git-home")
	if got := HomeDir(); got != "/custom/git-home" {
		t.Errorf("HomeDir with GIT_HOME = %q, want /custom/git-home", got)
	}

	old, hadOld := os.LookupEnv("GIT_HOME")
	os.Unsetenv("GIT_HOME")
	defer func() {
		if hadOld {
			os.Setenv("GIT_HOME", old)
		}
	}()
	if got := HomeDir(); got != os.TempDir() {
		t.Errorf("HomeDir without GIT_HOME = %q, want %q", got, os.TempDir())
	}
}

func TestCommonEnvs(t *testing.T) {
	envs := CommonEnvs()

	if len(envs) != 5 {
		t.Errorf("len(CommonEnvs) = %d, want 5", len(envs))
	}
	if v, ok := getEnvValue(envs, "HOME"); !ok || v == "" {
		t.Errorf("HOME missing or empty in %v", envs)
	}
	if v, _ := getEnvValue(envs, "HOME"); v != HomeDir() {
		t.Errorf("HOME = %q, want HomeDir() = %q", v, HomeDir())
	}
	for _, want := range []string{
		"GIT_CONFIG_NOSYSTEM=1",
		"GIT_NO_REPLACE_OBJECTS=1",
		"GIT_TERMINAL_PROMPT=0",
		"LC_ALL=C",
	} {
		if _, ok := getEnvValue(envs, strings.SplitN(want, "=", 2)[0]); !ok {
			t.Errorf("CommonEnvs missing %q in %v", want, envs)
		}
	}
}

func TestVersionContext(t *testing.T) {
	if _, err := Version(context.Background()); err != nil {
		t.Fatalf("Version: %v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	if _, err := Version(ctx); err == nil {
		t.Error("expected error from cancelled context, got nil")
	}
}

func TestExecutableFoundViaLookPath(t *testing.T) {
	exe, err := Executable()
	if err != nil {
		t.Fatalf("Executable: %v", err)
	}
	looked, err := exec.LookPath("git")
	if err != nil {
		t.Skip("git not on PATH")
	}

	if exe == "" {
		t.Error("empty executable path")
	}
	_ = looked
}