package rushlink

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"gitea.hashru.nl/dsprenkels/rushlink/internal/db"
	"github.com/gorilla/mux"
)

// createTemporaryRouter initializes a rushlink instance, with temporary
// filestore and database.
//
// It will use testing.T.Cleanup to cleanup after itself.
func createTemporaryRouter(t *testing.T) (*mux.Router, *rushlink) {
	tempDir, err := ioutil.TempDir("", "rushlink-tmp-*")
	if err != nil {
		t.Fatalf("creating temporary directory: %s\n", err)
	}
	t.Cleanup(func() {
		os.RemoveAll(tempDir)
	})

	fileStore, err := db.OpenFileStore(filepath.Join(tempDir, "filestore"))
	if err != nil {
		t.Fatalf("opening temporary filestore: %s\n", err)
	}

	os.Setenv(db.EnvDatabaseDriver, "sqlite")
	os.Setenv(db.EnvDatabasePath, "file::memory:?cache=shared")

	database, err := db.OpenDBFromEnvironment()
	if err != nil {
		t.Fatalf("opening temporary database: %v\n", err)
	}
	database.Debug()
	if err := db.Gormigrate(database).Migrate(); err != nil {
		t.Fatalf("migration failed: %v\n", err)
	}

	// *.invalid. is guaranteed not to exist (RFC 6761).
	rootURL, err := url.Parse("https://rushlink.invalid")
	if err != nil {
		t.Fatalf("parsing URL: %s\n", err)
	}

	rl := rushlink{
		db:      database,
		fs:      fileStore,
		rootURL: rootURL,
	}
	r := mux.NewRouter()
	InitMainRouter(r, &rl)
	return r, &rl
}

// checkStatusCode checks whether the status code from a recorded response is equal
// to some response code.
func checkStatusCode(t *testing.T, rr *httptest.ResponseRecorder, code int) {
	if actual := rr.Code; actual != code {
		t.Logf("request body:\n%v\n", rr.Body.String())
		t.Fatalf("handler returned wrong status code: got %v want %v\n",
			actual, code)
	}
}

// checkLocationHeader checks whether the status code from a recorded response is equal
// to some expected URL.
func checkLocationHeader(t *testing.T, rr *httptest.ResponseRecorder, expected string) {
	location := rr.Header().Get("Location")
	if location != expected {
		t.Fatalf("handler returned bad redirect location: got %v want %v", location, expected)
	}
}

func TestIssue43(t *testing.T) {
	srv, _ := createTemporaryRouter(t)

	// Put a URL with a fragment identifier into the database.
	var body bytes.Buffer
	form := multipart.NewWriter(&body)
	form.WriteField("shorten", "https://example.com#fragment")
	form.Close()
	req, err := http.NewRequest("POST", "/", bytes.NewReader(body.Bytes()))
	if err != nil {
		t.Fatal(err)
	}
	req.Header.Add("Content-Type", form.FormDataContentType())
	rr := httptest.NewRecorder()
	srv.ServeHTTP(rr, req)
	checkStatusCode(t, rr, http.StatusFound)
	rawURL := strings.SplitN(rr.Body.String(), "\n", 2)[0]
	pasteURL, err := url.Parse(rawURL)
	if err != nil {
		t.Fatal(err)
	}

	// Check if the URL was encoded correctly.
	req, err = http.NewRequest("GET", pasteURL.Path, nil)
	if err != nil {
		t.Fatal(err)
	}
	req = mux.SetURLVars(req, map[string]string{"key": pasteURL.Path[1:]})
	rr = httptest.NewRecorder()
	srv.ServeHTTP(rr, req)
	checkStatusCode(t, rr, http.StatusTemporaryRedirect)
	checkLocationHeader(t, rr, "https://example.com#fragment")
}

func TestIssue53(t *testing.T) {
	srv, rl := createTemporaryRouter(t)

	// Put a URL with a fragment identifier into the database.
	var body bytes.Buffer
	form := multipart.NewWriter(&body)
	if _, err := form.CreateFormFile("file", "../directory-traversal/file.txt"); err != nil {
		t.Fatal(err)
	}
	form.Close()
	req, err := http.NewRequest("POST", "/", bytes.NewReader(body.Bytes()))
	if err != nil {
		t.Fatal(err)
	}
	req.Header.Add("Content-Type", form.FormDataContentType())
	rr := httptest.NewRecorder()
	srv.ServeHTTP(rr, req)
	checkStatusCode(t, rr, http.StatusFound)

	// Check that any attempt to do directory traversal has failed.
	rl.db.Transaction(func(tx *db.Database) error {
		fus, err := db.AllFileUploads(tx)
		if err != nil {
			t.Fatal(err)
		}
		for _, fu := range fus {
			if strings.ContainsAny(fu.FileName, "/\\") {
				t.Fatalf(fmt.Sprintf("found a slash in file name: %v", fu.FileName))
			}
		}
		return nil
	})
}

func TestIssue60(t *testing.T) {
	srv, _ := createTemporaryRouter(t)

	// Request a nonexistent static file
	req, err := http.NewRequest("GET", "/css/nonexistent_file.css", nil)
	if err != nil {
		t.Fatal(err)
	}
	rr := httptest.NewRecorder()
	srv.ServeHTTP(rr, req)
	checkStatusCode(t, rr, http.StatusNotFound)
}

func TestIssue56(t *testing.T) {
	srv, _ := createTemporaryRouter(t)

	// Make a POST request with both a 'file' *and* a 'shorten' part.
	var body bytes.Buffer
	form := multipart.NewWriter(&body)
	if _, err := form.CreateFormFile("file", "empty.txt"); err != nil {
		t.Fatal(err)
	}
	if _, err := form.CreateFormField("shorten"); err != nil {
		t.Fatal(err)
	}
	form.Close()
	req, err := http.NewRequest("POST", "/", bytes.NewReader(body.Bytes()))
	if err != nil {
		t.Fatal(err)
	}
	req.Header.Add("Content-Type", form.FormDataContentType())
	rr := httptest.NewRecorder()
	srv.ServeHTTP(rr, req)
	checkStatusCode(t, rr, http.StatusBadRequest)
}

func TestIssue68(t *testing.T) {
	srv, _ := createTemporaryRouter(t)
	originalURL := "https://example.com"

	var body bytes.Buffer
	form := multipart.NewWriter(&body)
	form.WriteField("shorten", "https://example.com")
	form.Close()
	req, err := http.NewRequest("POST", "/", bytes.NewReader(body.Bytes()))
	if err != nil {
		t.Fatal(err)
	}
	req.Header.Add("Content-Type", form.FormDataContentType())
	rr := httptest.NewRecorder()
	srv.ServeHTTP(rr, req)
	checkStatusCode(t, rr, http.StatusFound)
	rawURL := strings.SplitN(rr.Body.String(), "\n", 2)[0]
	pasteURL, err := url.Parse(rawURL)
	if err != nil {
		t.Fatal(err)
	}

	// Check if the no-redirect handler works properly.
	req, err = http.NewRequest("GET", pasteURL.Path+"/nr", nil)
	if err != nil {
		t.Fatal(err)
	}
	rr = httptest.NewRecorder()
	srv.ServeHTTP(rr, req)
	checkStatusCode(t, rr, http.StatusOK)
	if rr.Body.String() != originalURL {
		t.Errorf("incorrect URL = %v, want %v", rr.Body.String(), originalURL)
	}
}