package handlers

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"

	"golang.org/x/oauth2"

	"task-dashboard/internal/api"
)

func withSession(t *testing.T, h *Handler, req *http.Request) *http.Request {
	t.Helper()
	ctx, err := h.sessions.Load(req.Context(), "")
	if err != nil {
		t.Fatal(err)
	}
	return req.WithContext(ctx)
}

func TestHandleGoogleTasksOAuthStart_NotConfigured_Returns503(t *testing.T) {
	h, cleanup := setupTestHandler(t)
	defer cleanup()

	req := withSession(t, h, httptest.NewRequest("GET", "/settings/google-tasks/connect", nil))
	w := httptest.NewRecorder()
	h.HandleGoogleTasksOAuthStart(w, req)

	if w.Code != http.StatusServiceUnavailable {
		t.Errorf("status = %d, want 503", w.Code)
	}
}

func TestHandleGoogleTasksOAuthStart_RedirectsToGoogleAndStoresState(t *testing.T) {
	h, cleanup := setupTestHandler(t)
	defer cleanup()
	h.googleTasksOAuthConfig = api.GoogleTasksOAuthConfig("client-id", "client-secret", "https://doot.terst.org/settings/google-tasks/callback")

	req := withSession(t, h, httptest.NewRequest("GET", "/settings/google-tasks/connect", nil))
	w := httptest.NewRecorder()
	h.HandleGoogleTasksOAuthStart(w, req)

	if w.Code != http.StatusFound {
		t.Fatalf("status = %d, want 302", w.Code)
	}
	loc := w.Header().Get("Location")
	if loc == "" {
		t.Fatal("no Location header set")
	}

	state := h.sessions.GetString(req.Context(), sessionKeyGoogleOAuthState)
	if state == "" {
		t.Error("expected a state value to be stored in session")
	}
}

func TestHandleGoogleTasksOAuthCallback_StateMismatch_Returns400(t *testing.T) {
	h, cleanup := setupTestHandler(t)
	defer cleanup()
	h.googleTasksOAuthConfig = api.GoogleTasksOAuthConfig("client-id", "client-secret", "https://doot.terst.org/settings/google-tasks/callback")

	req := httptest.NewRequest("GET", "/settings/google-tasks/callback?state=wrong&code=abc", nil)
	req = withSession(t, h, req)
	h.sessions.Put(req.Context(), sessionKeyGoogleOAuthState, "expected-state")

	w := httptest.NewRecorder()
	h.HandleGoogleTasksOAuthCallback(w, req)

	if w.Code != http.StatusBadRequest {
		t.Errorf("status = %d, want 400", w.Code)
	}
	if tok, _ := h.store.GetOAuthToken(api.GoogleTasksOAuthSource); tok != nil {
		t.Error("no token should have been saved on state mismatch")
	}
}

func TestHandleGoogleTasksOAuthCallback_GoogleReturnedError_RedirectsWithError(t *testing.T) {
	h, cleanup := setupTestHandler(t)
	defer cleanup()
	h.googleTasksOAuthConfig = api.GoogleTasksOAuthConfig("client-id", "client-secret", "https://doot.terst.org/settings/google-tasks/callback")

	req := withSession(t, h, httptest.NewRequest("GET", "/settings/google-tasks/callback?error=access_denied", nil))
	w := httptest.NewRecorder()
	h.HandleGoogleTasksOAuthCallback(w, req)

	if w.Code != http.StatusFound {
		t.Fatalf("status = %d, want 302", w.Code)
	}
	loc := w.Header().Get("Location")
	if loc != "/settings?google_tasks_error=access_denied" {
		t.Errorf("Location = %q", loc)
	}
}

func TestHandleGoogleTasksOAuthDisconnect_RemovesStoredToken(t *testing.T) {
	h, cleanup := setupTestHandler(t)
	defer cleanup()

	if err := h.store.SaveOAuthToken(api.GoogleTasksOAuthSource, &oauth2.Token{AccessToken: "a", RefreshToken: "r"}); err != nil {
		t.Fatal(err)
	}

	req := withSession(t, h, httptest.NewRequest("POST", "/settings/google-tasks/disconnect", nil))
	w := httptest.NewRecorder()
	h.HandleGoogleTasksOAuthDisconnect(w, req)

	if w.Code != http.StatusFound {
		t.Fatalf("status = %d, want 302", w.Code)
	}
	tok, err := h.store.GetOAuthToken(api.GoogleTasksOAuthSource)
	if err != nil {
		t.Fatal(err)
	}
	if tok != nil {
		t.Error("token should be gone after disconnect")
	}
}

func TestHandleSettingsPage_ReflectsGoogleTasksConnectionState(t *testing.T) {
	h, cleanup := setupTestHandler(t)
	defer cleanup()
	h.googleTasksOAuthConfig = api.GoogleTasksOAuthConfig("client-id", "client-secret", "https://doot.terst.org/settings/google-tasks/callback")

	req := withSession(t, h, httptest.NewRequest("GET", "/settings", nil))
	w := httptest.NewRecorder()
	h.HandleSettingsPage(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200, body=%s", w.Code, w.Body.String())
	}
	mock := h.renderer.(*MockRenderer)
	data := mock.Calls[len(mock.Calls)-1].Data
	type settingsData struct {
		GoogleTasksOAuthReady bool
		GoogleTasksConnected  bool
	}
	jsonBytes, _ := json.Marshal(data)
	var got settingsData
	_ = json.Unmarshal(jsonBytes, &got)
	if !got.GoogleTasksOAuthReady {
		t.Error("GoogleTasksOAuthReady = false, want true (config was set)")
	}
	if got.GoogleTasksConnected {
		t.Error("GoogleTasksConnected = true, want false (no token saved)")
	}

	if err := h.store.SaveOAuthToken(api.GoogleTasksOAuthSource, &oauth2.Token{AccessToken: "a", RefreshToken: "r"}); err != nil {
		t.Fatal(err)
	}
	w2 := httptest.NewRecorder()
	h.HandleSettingsPage(w2, req)
	data2 := mock.Calls[len(mock.Calls)-1].Data
	jsonBytes2, _ := json.Marshal(data2)
	var got2 settingsData
	_ = json.Unmarshal(jsonBytes2, &got2)
	if !got2.GoogleTasksConnected {
		t.Error("GoogleTasksConnected = false, want true after saving a token")
	}
}