package downloader

import (
	"context"
	"errors"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"sync/atomic"
	"testing"
)

func TestPathMap(t *testing.T) {
	m := PathMap{Local: "/downloads", Remote: "/data/torrents/"}
	for in, want := range map[string]string{
		"/downloads":           "/data/torrents",
		"/downloads/abc/x.mp3": "/data/torrents/abc/x.mp3",
		"/downloads2/abc":      "/downloads2/abc",
		"/music/a":             "/music/a",
		"":                     "",
	} {
		if got := m.ToRemote(in); got != want {
			t.Errorf("ToRemote(%q) = %q, want %q", in, got, want)
		}
	}
	if got := m.ToLocal("/data/torrents/abc"); got != "/downloads/abc" {
		t.Errorf("ToLocal = %q", got)
	}
	if (PathMap{Local: "/downloads", Remote: "/downloads/"}).Active() {
		t.Error("the same folder under one name is not a mapping")
	}
}

// fakeQbit is a qBittorrent WebUI that wants a login, and that expires the
// session once to make the client log in again.
func fakeQbit(t *testing.T, expireOnce bool) (*httptest.Server, *atomic.Int32) {
	t.Helper()
	var logins atomic.Int32
	var expired atomic.Bool
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Header.Get("Referer") == "" {
			w.WriteHeader(http.StatusForbidden)
			return
		}
		switch r.URL.Path {
		case "/api/v2/auth/login":
			_ = r.ParseForm()
			if r.Form.Get("password") != "pw" {
				_, _ = w.Write([]byte("Fails."))
				return
			}
			logins.Add(1)
			http.SetCookie(w, &http.Cookie{Name: "SID", Value: "s", Path: "/"})
			_, _ = w.Write([]byte("Ok."))
		case "/api/v2/torrents/info":
			if _, err := r.Cookie("SID"); err != nil {
				w.WriteHeader(http.StatusForbidden)
				return
			}
			if expireOnce && !expired.Swap(true) {
				w.WriteHeader(http.StatusForbidden)
				return
			}
			if r.URL.Query().Get("category") != "minstrel" {
				t.Errorf("category = %q", r.URL.Query().Get("category"))
			}
			_, _ = w.Write([]byte(`[{"hash": "ABC", "name": "x", "save_path": "/data/torrents/abc", "progress": 1}]`))
		case "/api/v2/torrents/add":
			body, _ := io.ReadAll(r.Body)
			if !strings.Contains(string(body), "/data/torrents/new") {
				t.Errorf("add body has no translated save path: %s", body)
			}
			_, _ = w.Write([]byte("Ok."))
		default:
			w.WriteHeader(http.StatusNotFound)
		}
	}))
	t.Cleanup(srv.Close)
	return srv, &logins
}

func TestQBittorrent_LogsInAndLogsInAgainWhenTheSessionExpires(t *testing.T) {
	srv, logins := fakeQbit(t, true)
	d := Mapped(&Client{Config: Config{BaseURL: srv.URL, Username: "u", Password: "pw", Category: "minstrel"}},
		PathMap{Local: "/downloads", Remote: "/data/torrents"})
	ts, err := d.Torrents(context.Background())
	if err != nil {
		t.Fatalf("torrents: %v", err)
	}
	if logins.Load() != 2 {
		t.Errorf("logins = %d, want 2 (the second after the 403)", logins.Load())
	}
	if len(ts) != 1 || ts[0].Hash != "abc" || ts[0].SavePath != "/downloads/abc" || !ts[0].Done() {
		t.Errorf("torrents = %+v, want one, hash lowercased, path in Minstrel's terms", ts)
	}
	if err := d.AddTorrent(context.Background(), Add{Magnet: "magnet:?xt=urn:btih:abc", SavePath: "/downloads/new"}); err != nil {
		t.Errorf("add: %v", err)
	}
}

func TestQBittorrent_AWrongPasswordIsAuth(t *testing.T) {
	srv, _ := fakeQbit(t, false)
	c := &Client{Config: Config{BaseURL: srv.URL, Password: "nope"}}
	if _, err := c.Torrents(context.Background()); !errors.Is(err, ErrAuth) {
		t.Fatalf("err = %v, want ErrAuth", err)
	}
}

func TestExchange_MapsDownloadsAndRefusesWhileRestoring(t *testing.T) {
	var restoring, sentKey atomic.Bool
	restoring.Store(true)
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Header.Get("Authorization") != "" {
			sentKey.Store(true)
		}
		pending := "0"
		if restoring.Load() {
			pending = "3"
		}
		_, _ = io.WriteString(w, `{"enabled": true, "running": false, "held_reason": "disk full", "restore_pending": `+pending+`, "downloads": [
			{"infohash": "ABC", "name": "Album", "save_path": "/dl", "state": "seeding", "progress": 1, "length": 10, "bytes": 10, "category": "minstrel"},
			{"infohash": "DEF", "name": "Other", "save_path": "/dl", "state": "fast", "category": "someone-else"},
			{"infohash": "123", "name": "Broken", "save_path": "/dl", "failed": true, "fail_reason": "tracker gone", "category": "minstrel"}
		]}`)
	}))
	defer srv.Close()

	c := &Exchange{Config: Config{BaseURL: srv.URL, Category: "minstrel"}}
	if _, err := c.Torrents(context.Background()); !errors.Is(err, ErrRestoring) {
		t.Fatalf("while restoring: err = %v, want ErrRestoring", err)
	}
	if sentKey.Load() {
		t.Error("an Authorization header was sent with no key set")
	}
	restoring.Store(false)
	ts, err := c.Torrents(context.Background())
	if err != nil {
		t.Fatalf("torrents: %v", err)
	}
	if len(ts) != 2 {
		t.Fatalf("torrents = %+v, want the two in Minstrel's category", ts)
	}
	if ts[0].Hash != "abc" || ts[0].State != "uploading" || ts[0].ContentPath != "/dl/Album" || !strings.Contains(ts[0].EngineDown, "disk full") {
		t.Errorf("first = %+v", ts[0])
	}
	if !ts[1].Failed() || ts[1].FailReason != "tracker gone" {
		t.Errorf("second = %+v, want failed with Exchange's reason", ts[1])
	}
}

func TestFor_RefusesAnUnknownProtocol(t *testing.T) {
	if _, err := For("transmission", Config{}); err == nil {
		t.Fatal("want an error for a client Minstrel cannot drive")
	}
}