package web

import (
	"net/http"
	"net/http/httptest"
	"net/url"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/scottyah/tracker/internal/config"
	"github.com/scottyah/tracker/internal/store"
)

// newServer builds a server whose "today" is fixed, so the day arithmetic is
// the same in January as it is in July.
func newServer(t *testing.T, today string) (*Server, *store.Store) {
	t.Helper()

	tz, err := time.LoadLocation("America/Los_Angeles")
	if err != nil {
		t.Fatal(err)
	}
	st, err := store.Open(filepath.Join(t.TempDir(), "tracker.json"))
	if err != nil {
		t.Fatal(err)
	}
	srv, err := New(&config.Config{Addr: ":0", BaseURL: "http://test", TZ: tz}, st)
	if err != nil {
		t.Fatal(err)
	}
	srv.now = func() time.Time {
		d, err := time.ParseInLocation(store.DateLayout, today, tz)
		if err != nil {
			t.Fatal(err)
		}
		return d.Add(9 * time.Hour) // mid-morning, well inside the local day
	}
	return srv, st
}

func configured() store.Settings {
	s := store.Defaults()
	s.StartDate = "2026-06-20"
	return s
}

func get(t *testing.T, srv *Server, path string) *httptest.ResponseRecorder {
	t.Helper()
	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, path, nil))
	return rec
}

func post(t *testing.T, srv *Server, path string, form url.Values) *httptest.ResponseRecorder {
	t.Helper()
	req := httptest.NewRequest(http.MethodPost, path, strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, req)
	return rec
}

func TestHomeAsksForSetupFirst(t *testing.T) {
	srv, _ := newServer(t, "2026-07-31")

	rec := get(t, srv, "/")
	if rec.Code != http.StatusOK {
		t.Fatalf("status %d", rec.Code)
	}
	if !strings.Contains(rec.Body.String(), "Start the challenge") {
		t.Error("an unconfigured tracker should open on the setup form")
	}
}

func TestHomeShowsToday(t *testing.T) {
	srv, st := newServer(t, "2026-07-31")
	st.SaveSettings(configured())

	body := get(t, srv, "/").Body.String()
	if !strings.Contains(body, "Friday 31 July") {
		t.Error("today's date is missing from the page")
	}
	// 2026-06-20 is day 1, so 2026-07-31 is day 42.
	if !strings.Contains(body, `<p class="masthead-count">42</p>`) {
		t.Error("the day number is wrong or missing")
	}
}

func TestSaveDayRoundTrips(t *testing.T) {
	srv, st := newServer(t, "2026-07-31")
	st.SaveSettings(configured())

	rec := post(t, srv, "/d/2026-07-30", url.Values{
		"workout":    {"1"},
		"protein":    {"186"},
		"calories":   {"2140"},
		"water":      {"132"},
		"gratitude1": {"Coffee"},
		"gratitude2": {"  Dog  "},
		"gratitude3": {"Squats"},
	})
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status %d, want a redirect back to the day", rec.Code)
	}

	day := st.Day("2026-07-30")
	if !day.Workout || *day.Protein != 186 || *day.Calories != 2140 || *day.Water != 132 {
		t.Fatalf("day did not save: %+v", day)
	}
	if day.Gratitude[1] != "Dog" {
		t.Errorf("gratitude kept its whitespace: %q", day.Gratitude[1])
	}
	if !configured().Marks(day).Complete() {
		t.Error("a day hitting all five did not score 5")
	}

	if body := get(t, srv, "/d/2026-07-30").Body.String(); !strings.Contains(body, `value="186"`) {
		t.Error("the saved protein is not back in the form")
	}
}

func TestBackgroundSaveAnswersWithTheScore(t *testing.T) {
	srv, st := newServer(t, "2026-07-31")
	st.SaveSettings(configured())

	req := httptest.NewRequest(http.MethodPost, "/d/2026-07-31",
		strings.NewReader(url.Values{"workout": {"1"}, "water": {"130"}}.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.Header.Set("X-Sync", "1")

	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status %d", rec.Code)
	}
	if got := rec.Body.String(); !strings.Contains(got, `"score":2`) {
		t.Errorf("body %s, want a score of 2", got)
	}
}

func TestSaveRejectsNonNumbers(t *testing.T) {
	srv, st := newServer(t, "2026-07-31")
	st.SaveSettings(configured())

	rec := post(t, srv, "/d/2026-07-31", url.Values{"protein": {"lots"}})
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status %d, want 400", rec.Code)
	}
	if st.Day("2026-07-31").Logged() {
		t.Error("a rejected form still wrote to the file")
	}
}

func TestBadDatesAreNotFound(t *testing.T) {
	srv, st := newServer(t, "2026-07-31")
	st.SaveSettings(configured())

	for _, date := range []string{"2026-13-01", "2026-2-03", "tuesday", "2026-02-30"} {
		if rec := get(t, srv, "/d/"+date); rec.Code != http.StatusNotFound {
			t.Errorf("GET /d/%s = %d, want 404", date, rec.Code)
		}
	}
}

func TestNavigationStopsAtTodayAndAtTheEnds(t *testing.T) {
	srv, st := newServer(t, "2026-07-31")
	st.SaveSettings(configured())

	if got := srv.step(configured(), "2026-06-20", -1); got != "" {
		t.Errorf("stepped back past day 1 to %q", got)
	}
	if got := srv.step(configured(), "2026-07-31", +1); got != "" {
		t.Errorf("stepped forward into tomorrow, to %q", got)
	}
	if got := srv.step(configured(), "2026-07-30", +1); got != "2026-07-31" {
		t.Errorf("step forward = %q, want 2026-07-31", got)
	}
}

func TestStreakIgnoresAnUnfinishedToday(t *testing.T) {
	srv, st := newServer(t, "2026-07-31")
	settings := configured()
	st.SaveSettings(settings)

	perfect := func(date string) {
		st.SaveDay(store.Day{Date: date, Workout: true, Protein: intp(200),
			Calories: intp(2000), Water: intp(130),
			Gratitude: [3]string{"a", "b", "c"}})
	}
	perfect("2026-07-28")
	perfect("2026-07-29")
	perfect("2026-07-30")
	// Nothing logged for today yet: the streak is still three, not broken.

	if got := srv.stats(settings, srv.card(settings)).Streak; got != 3 {
		t.Errorf("streak = %d, want 3", got)
	}

	perfect("2026-07-31")
	if got := srv.stats(settings, srv.card(settings)).Streak; got != 4 {
		t.Errorf("streak after finishing today = %d, want 4", got)
	}

	// A gap two days back ends the run at yesterday and today.
	st.SaveDay(store.Day{Date: "2026-07-30"})
	if got := srv.stats(settings, srv.card(settings)).Streak; got != 1 {
		t.Errorf("streak across a missed day = %d, want 1", got)
	}
}

func TestCrossSiteWritesAreRefused(t *testing.T) {
	srv, st := newServer(t, "2026-07-31")
	st.SaveSettings(configured())

	req := httptest.NewRequest(http.MethodPost, "/d/2026-07-31",
		strings.NewReader("workout=1"))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.Header.Set("Sec-Fetch-Site", "cross-site")

	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, req)

	if rec.Code != http.StatusForbidden {
		t.Fatalf("status %d, want 403", rec.Code)
	}
	if st.Day("2026-07-31").Logged() {
		t.Error("a cross-site post still wrote to the log")
	}
}

func TestExportThenImport(t *testing.T) {
	srv, st := newServer(t, "2026-07-31")
	st.SaveSettings(configured())
	st.SaveDay(store.Day{Date: "2026-07-30", Workout: true})

	rec := get(t, srv, "/export.json")
	if rec.Code != http.StatusOK {
		t.Fatalf("status %d", rec.Code)
	}
	if !strings.Contains(rec.Header().Get("Content-Disposition"), "tracker-2026-07-31.json") {
		t.Errorf("download name = %q", rec.Header().Get("Content-Disposition"))
	}

	fresh, err := store.Open(filepath.Join(t.TempDir(), "tracker.json"))
	if err != nil {
		t.Fatal(err)
	}
	if err := fresh.Import(rec.Body.Bytes()); err != nil {
		t.Fatalf("import: %v", err)
	}
	if !fresh.Day("2026-07-30").Workout || fresh.Settings().StartDate != "2026-06-20" {
		t.Error("the export did not carry the log and the settings")
	}
}

func TestLandingBeforeTheChallengeStarts(t *testing.T) {
	srv, st := newServer(t, "2026-06-01")
	st.SaveSettings(configured())

	body := get(t, srv, "/").Body.String()
	if !strings.Contains(body, "Nothing counts until then") {
		t.Error("a challenge that has not started should say so")
	}
	if !strings.Contains(body, `<p class="masthead-count">1</p>`) {
		t.Error("it should land on day 1 rather than a date outside the challenge")
	}
}

func intp(n int) *int { return &n }