package main

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

	"github.com/gin-gonic/gin"
)

// newUploadsRouter builds a router with the production upload routes over a
// temp storage root that mirrors the real layout: the SQLite database file
// lives in the root itself, uploads live in subdirectories.
func newUploadsRouter(t *testing.T, storageDir string) (*gin.Engine, string) {
	t.Helper()
	gin.SetMode(gin.TestMode)

	root := t.TempDir()
	if err := os.WriteFile(filepath.Join(root, "blog.db"), []byte("fake sqlite"), 0644); err != nil {
		t.Fatalf("seed blog.db: %v", err)
	}

	r := gin.New()
	registerUploadRoutes(r.Group("/uploads"), root, storageDir)
	return r, root
}

func doGet(t *testing.T, r *gin.Engine, path string) *httptest.ResponseRecorder {
	t.Helper()
	w := httptest.NewRecorder()
	r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, path, nil))
	return w
}

func seedUploadFile(t *testing.T, root, sub, name string) {
	t.Helper()
	dir := filepath.Join(root, sub)
	if err := os.MkdirAll(dir, 0755); err != nil {
		t.Fatalf("mkdir %s: %v", dir, err)
	}
	if err := os.WriteFile(filepath.Join(dir, name), []byte("content"), 0644); err != nil {
		t.Fatalf("seed %s: %v", name, err)
	}
}

func TestUploadsWhitelistHidesStorageRoot(t *testing.T) {
	r, root := newUploadsRouter(t, "")
	for _, sub := range []string{"attachments", "avatars", "logos"} {
		seedUploadFile(t, root, sub, "file.txt")
	}

	// The database file in the storage root must not be downloadable.
	if w := doGet(t, r, "/uploads/blog.db"); w.Code != http.StatusNotFound {
		t.Fatalf("GET /uploads/blog.db = %d, want 404 (database leak)", w.Code)
	}

	// No directory listing anywhere.
	for _, p := range []string{
		"/uploads", "/uploads/",
		"/uploads/attachments/", "/uploads/avatars/", "/uploads/logos/",
	} {
		if w := doGet(t, r, p); w.Code != http.StatusNotFound {
			t.Fatalf("GET %s = %d, want 404 (no directory listing)", p, w.Code)
		}
	}

	// Traversal attempts must not escape the subdirectory.
	for _, p := range []string{
		"/uploads/attachments/../blog.db",
		"/uploads/attachments/..%2f..%2fblog.db",
		"/uploads/attachments/%2e%2e/blog.db",
	} {
		if w := doGet(t, r, p); w.Code == http.StatusOK {
			t.Fatalf("GET %s = %d, want non-200 (traversal)", p, w.Code)
		}
	}

	// Files in the whitelisted subdirectories are still served.
	for _, p := range []string{
		"/uploads/attachments/file.txt",
		"/uploads/avatars/file.txt",
		"/uploads/logos/file.txt",
	} {
		if w := doGet(t, r, p); w.Code != http.StatusOK {
			t.Fatalf("GET %s = %d, want 200", p, w.Code)
		}
	}
}

func TestUploadsWhitelistCustomStorageDir(t *testing.T) {
	r, root := newUploadsRouter(t, "files")
	seedUploadFile(t, root, "files", "a.bin")

	if w := doGet(t, r, "/uploads/files/a.bin"); w.Code != http.StatusOK {
		t.Fatalf("GET /uploads/files/a.bin = %d, want 200", w.Code)
	}
	// The default dir stays mounted for backward compatibility.
	seedUploadFile(t, root, "attachments", "old.txt")
	if w := doGet(t, r, "/uploads/attachments/old.txt"); w.Code != http.StatusOK {
		t.Fatalf("GET /uploads/attachments/old.txt = %d, want 200", w.Code)
	}
	if w := doGet(t, r, "/uploads/blog.db"); w.Code != http.StatusNotFound {
		t.Fatalf("GET /uploads/blog.db = %d, want 404", w.Code)
	}
}

func TestUploadsWhitelistUnsafeStorageDirFallsBack(t *testing.T) {
	for _, dir := range []string{"../evil", "/etc", "..", "a/../../b", "."} {
		r, root := newUploadsRouter(t, dir)
		seedUploadFile(t, root, "attachments", "file.txt")
		if w := doGet(t, r, "/uploads/attachments/file.txt"); w.Code != http.StatusOK {
			t.Fatalf("storage dir %q: fallback mount broken: %d", dir, w.Code)
		}
		if w := doGet(t, r, "/uploads/blog.db"); w.Code != http.StatusNotFound {
			t.Fatalf("storage dir %q: /uploads/blog.db = %d, want 404", dir, w.Code)
		}
	}
}

func TestUploadsWhitelistStorageDirDedup(t *testing.T) {
	// A storage dir equal to a known dir must not panic on duplicate routes.
	r, root := newUploadsRouter(t, "avatars")
	seedUploadFile(t, root, "avatars", "me.jpg")
	if w := doGet(t, r, "/uploads/avatars/me.jpg"); w.Code != http.StatusOK {
		t.Fatalf("GET /uploads/avatars/me.jpg = %d, want 200", w.Code)
	}
}