package streaming

import (
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"testing"
)

func setupFolder(t *testing.T) (root string) {
	t.Helper()
	root = t.TempDir()
	if err := os.MkdirAll(filepath.Join(root, "Artist", "Album"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(root, "Artist", "Album", "song.mp3"), []byte("0123456789"), 0o644); err != nil {
		t.Fatal(err)
	}
	return root
}

func TestResolvePathAllowsFileWithinFolder(t *testing.T) {
	root := setupFolder(t)
	got, err := ResolvePath(root, "Artist/Album/song.mp3")
	if err != nil {
		t.Fatalf("ResolvePath: %v", err)
	}
	want, _ := filepath.EvalSymlinks(filepath.Join(root, "Artist", "Album", "song.mp3"))
	if got != want {
		t.Errorf("ResolvePath = %q, want %q", got, want)
	}
}

func TestResolvePathRejectsTraversal(t *testing.T) {
	root := setupFolder(t)
	// A secret file just outside the music folder root.
	if err := os.WriteFile(filepath.Join(filepath.Dir(root), "secret.txt"), []byte("nope"), 0o644); err != nil {
		t.Fatal(err)
	}
	_, err := ResolvePath(root, "../secret.txt")
	if err == nil {
		t.Fatal("expected ResolvePath to reject a path escaping the folder root")
	}
}

func TestResolvePathRejectsDeepTraversal(t *testing.T) {
	root := setupFolder(t)
	_, err := ResolvePath(root, "Artist/../../../../../../etc/passwd")
	if err == nil {
		t.Fatal("expected ResolvePath to reject a deep traversal attempt")
	}
}

func TestServeFileSupportsRangeRequests(t *testing.T) {
	root := setupFolder(t)
	path := filepath.Join(root, "Artist", "Album", "song.mp3")

	req := httptest.NewRequest(http.MethodGet, "/stream/x", nil)
	req.Header.Set("Range", "bytes=2-5")
	rec := httptest.NewRecorder()

	if err := ServeFile(rec, req, path, "song.mp3"); err != nil {
		t.Fatalf("ServeFile: %v", err)
	}

	if rec.Code != http.StatusPartialContent {
		t.Fatalf("status = %d, want 206", rec.Code)
	}
	if got := rec.Body.String(); got != "2345" {
		t.Errorf("body = %q, want %q", got, "2345")
	}
	if cr := rec.Header().Get("Content-Range"); cr == "" {
		t.Error("expected Content-Range header on a range response")
	}
}

func TestServeFileFullBody(t *testing.T) {
	root := setupFolder(t)
	path := filepath.Join(root, "Artist", "Album", "song.mp3")

	req := httptest.NewRequest(http.MethodGet, "/stream/x", nil)
	rec := httptest.NewRecorder()
	if err := ServeFile(rec, req, path, "song.mp3"); err != nil {
		t.Fatalf("ServeFile: %v", err)
	}
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", rec.Code)
	}
	if rec.Body.String() != "0123456789" {
		t.Errorf("body = %q", rec.Body.String())
	}
	if rec.Header().Get("Accept-Ranges") != "bytes" {
		t.Error("expected Accept-Ranges: bytes header")
	}
}

func TestServeFileRejectsDirectory(t *testing.T) {
	root := setupFolder(t)
	req := httptest.NewRequest(http.MethodGet, "/stream/x", nil)
	rec := httptest.NewRecorder()
	if err := ServeFile(rec, req, filepath.Join(root, "Artist", "Album"), "Album"); err == nil {
		t.Fatal("expected error serving a directory")
	}
}

func TestMimeType(t *testing.T) {
	cases := map[string]string{
		"song.mp3":  "audio/mpeg",
		"song.flac": "audio/flac",
		"song.opus": "audio/opus",
		"song.m4a":  "audio/mp4",
		"song.xyz":  "application/octet-stream",
	}
	for path, want := range cases {
		if got := MimeType(path); got != want {
			t.Errorf("MimeType(%q) = %q, want %q", path, got, want)
		}
	}
}