package changelog_test

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/thokra/stamp/internal/changelog"
)

var testDate = time.Date(2026, 3, 8, 0, 0, 0, 0, time.UTC)

func TestAppend_NewFile(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "CHANGELOG.md")

	err := changelog.Append(path, changelog.Entry{
		Version:     "1.0.0",
		Date:        testDate,
		Description: "Initial release",
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	data, _ := os.ReadFile(path)
	content := string(data)

	if !strings.Contains(content, "## [1.0.0] - 2026-03-08") {
		t.Errorf("expected version header, got:\n%s", content)
	}
	if !strings.Contains(content, "Initial release") {
		t.Errorf("expected description in changelog")
	}
}

func TestAppend_ExistingFile(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "CHANGELOG.md")

	// Write first version.
	_ = changelog.Append(path, changelog.Entry{
		Version:     "1.0.0",
		Date:        testDate,
		Description: "First release",
	})

	// Append second version.
	_ = changelog.Append(path, changelog.Entry{
		Version:     "1.1.0",
		Date:        testDate.Add(24 * time.Hour),
		Description: "Second release",
	})

	data, _ := os.ReadFile(path)
	content := string(data)

	if !strings.Contains(content, "## [1.0.0]") {
		t.Error("expected 1.0.0 section")
	}
	if !strings.Contains(content, "## [1.1.0]") {
		t.Error("expected 1.1.0 section")
	}

	// New version should appear before old.
	idx110 := strings.Index(content, "## [1.1.0]")
	idx100 := strings.Index(content, "## [1.0.0]")
	if idx110 > idx100 {
		t.Error("expected 1.1.0 to appear before 1.0.0 (newest first)")
	}
}

func TestAppend_EmptyDescription(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "CHANGELOG.md")

	err := changelog.Append(path, changelog.Entry{
		Version: "2.0.0",
		Date:    testDate,
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	data, _ := os.ReadFile(path)
	if !strings.Contains(string(data), "## [2.0.0]") {
		t.Error("expected version header even with empty description")
	}
}

func TestAppend_CreatesDirectory(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "sub", "dir", "CHANGELOG.md")

	err := changelog.Append(path, changelog.Entry{
		Version: "1.0.0",
		Date:    testDate,
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if _, err := os.Stat(path); err != nil {
		t.Errorf("expected file to be created: %v", err)
	}
}