package gog

import (
	"context"
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"
)

// serveHome serves the given HTML for all requests.
func serveHome(t *testing.T, html string) *Client {
	t.Helper()
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.Header().Set("Content-Type", "text/html; charset=UTF-8")
		w.Write([]byte(html))
	}))
	t.Cleanup(srv.Close)
	c := NewClient()
	c.HTTP = srv.Client()
	// Point the client at the test server by overriding the home URL via
	// BaseURL-like behavior: homeURL is a package const, so we test through
	// the extraction path instead.
	_ = srv
	return c
}

// The live homepage embeds the giveaway in gogcom-store-state JSON.
func TestLiveFixture_GiveawayFromStoreState(t *testing.T) {
	html, err := os.ReadFile("testdata/home.html")
	if err != nil {
		t.Fatal(err)
	}
	state := extractStoreState(string(html))
	if state == "" {
		t.Fatal("gogcom-store-state script not found in live fixture")
	}

	sec, err := parseGiveawaySection([]byte(state))
	if err != nil {
		t.Fatalf("parse giveaway: %v", err)
	}
	if sec == nil {
		t.Fatal("no giveaway section found in live fixture")
	}
	if sec.Product == nil || sec.Product.Title == "" || sec.Product.Slug == "" {
		t.Fatalf("giveaway product incomplete: %+v", sec.Product)
	}
	if sec.Product.Slug != "a_new_beginning" {
		t.Errorf("slug = %q, want a_new_beginning (live giveaway Oct 2026)", sec.Product.Slug)
	}
	if sec.Product.ID == "" {
		t.Error("product id missing")
	}
	if sec.EndDate.IsZero() {
		t.Error("giveaway endDate missing")
	}
}

// Regression: the section is identified by STRUCTURE (endDate + product with
// slug/title), not by a fixed section UUID — survives layout changes.
func TestGiveawayRecognitionIsStructural(t *testing.T) {
	// A section with endDate + product anywhere in the state is found,
	// even under an arbitrary key.
	state := `{"someKey":{"x":{"endDate":"2026-11-02T16:00:59.000+02:00","product":{"id":"123","title":"Test Game","slug":"test_game"}}},"other":{"endDate":"2020-01-01T00:00:00Z","product":{"id":"0","title":"Old","slug":"old"}}}`
	sec, err := parseGiveawaySection([]byte(state))
	if err != nil {
		t.Fatal(err)
	}
	if sec == nil || sec.Product.Slug != "test_game" {
		t.Fatalf("structural detection failed: %+v", sec)
	}
}

// No store-state script → explicit error (the client must not pretend
// success with an empty list).
func TestMissingStoreStateIsAnError(t *testing.T) {
	if state := extractStoreState("<html><body>nothing here</body></html>"); state != "" {
		t.Fatalf("expected empty state, got %q", state)
	}
}

// A store-state without any giveaway object → nil section, no error.
func TestStateWithoutGiveawayYieldsNoSection(t *testing.T) {
	sec, err := parseGiveawaySection([]byte(`{"pageMetadata":{"locale":"en-US"}}`))
	if err != nil {
		t.Fatal(err)
	}
	if sec != nil {
		t.Fatalf("expected no section, got %+v", sec)
	}
}

// Broken store-state JSON → error, not panic.
func TestBrokenStoreStateJSONIsAnError(t *testing.T) {
	if _, err := parseGiveawaySection([]byte("{not json")); err == nil {
		t.Fatal("expected error for broken JSON")
	}
}

// The extraction handles the script tag with trailing content after </script>.
func TestExtractStoreStateTrimsScript(t *testing.T) {
	html := `<html><head><script id="gogcom-store-state" type="application/json">{"a":1}</script></head></html>`
	state := extractStoreState(html)
	if strings.TrimSpace(state) != `{"a":1}` {
		t.Fatalf("state = %q", state)
	}
}

// End-to-end via HTTP: client fetches the (test) homepage and extracts the
// giveaway. Uses a package-level URL override to avoid network.
func TestGetFreeGamesEndToEnd(t *testing.T) {
	html, err := os.ReadFile("testdata/home.html")
	if err != nil {
		t.Fatal(err)
	}
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.Write(html)
	}))
	t.Cleanup(srv.Close)

	c := NewClient()
	c.HTTP = srv.Client()
	c.HomeURL = srv.URL

	games, err := c.GetFreeGames(context.Background())
	if err != nil {
		t.Fatal(err)
	}
	if len(games) != 1 {
		t.Fatalf("want exactly 1 giveaway, got %d", len(games))
	}
	g := games[0]
	if g.Store != "gog" || g.Kind != "free-now" {
		t.Errorf("store/kind = %s/%s, want gog/free-now", g.Store, g.Kind)
	}
	if !strings.HasPrefix(g.ID, "gog-") {
		t.Errorf("id = %q, want gog- prefix", g.ID)
	}
	if g.URL == "" {
		t.Error("url missing")
	}
}