package handlers

import (
	"context"
	"io/fs"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"

	"github.com/glebarez/sqlite"
	"gorm.io/gorm"

	"nestly/internal/auth"
	"nestly/internal/models"
	"nestly/internal/templates"
	"nestly/web"
)

// newTestServer 建立以記憶體 SQLite 為後端的測試路由與示範帳號。
func newTestServer(t *testing.T) http.Handler {
	t.Helper()
	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
	if err != nil {
		t.Fatalf("開啟記憶體資料庫失敗: %v", err)
	}
	accounts := models.NewAccountStore(db)
	if err := accounts.AutoMigrate(context.Background()); err != nil {
		t.Fatalf("自動遷移失敗: %v", err)
	}
	acct := &models.Account{Email: "demo@nestly.test", Name: "示範帳號", Role: models.RoleMember}
	if err := acct.SetPassword("nestly1234"); err != nil {
		t.Fatalf("設定密碼失敗: %v", err)
	}
	if err := accounts.Create(context.Background(), acct); err != nil {
		t.Fatalf("建立帳號失敗: %v", err)
	}

	templateFS, err := fs.Sub(web.TemplatesFS, "templates")
	if err != nil {
		t.Fatalf("建立模板子目錄失敗: %v", err)
	}
	engine, err := templates.New(templateFS)
	if err != nil {
		t.Fatalf("載入模板失敗: %v", err)
	}
	return NewRouter(Dependencies{
		Templates: engine,
		Accounts:  accounts,
		Sessions:  auth.NewSessionManager("test-secret", false),
	})
}

func TestLoginPageRenders(t *testing.T) {
	srv := newTestServer(t)

	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/login", nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("GET /login 狀態碼 = %d, 想要 200", rec.Code)
	}
	body := rec.Body.String()
	for _, want := range []string{"登入", `name="email"`, `name="password"`} {
		if !strings.Contains(body, want) {
			t.Errorf("GET /login 回應缺少 %q", want)
		}
	}
}

func TestLoginWrongPassword(t *testing.T) {
	srv := newTestServer(t)

	form := url.Values{"email": {"demo@nestly.test"}, "password": {"wrong-password"}}
	req := httptest.NewRequest(http.MethodPost, "/login", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, req)

	if rec.Code != http.StatusUnauthorized {
		t.Fatalf("POST /login（錯誤密碼）狀態碼 = %d, 想要 401", rec.Code)
	}
	if body := rec.Body.String(); !strings.Contains(body, "Email 或密碼不正確") {
		t.Error("錯誤密碼應顯示錯誤訊息")
	}
	if body := rec.Body.String(); !strings.Contains(body, `value="demo@nestly.test"`) {
		t.Error("錯誤後應保留使用者輸入的 Email")
	}
}

func TestLoginSuccessFlow(t *testing.T) {
	srv := newTestServer(t)

	form := url.Values{"email": {"Demo@Nestly.test "}, "password": {"nestly1234"}} // email 大小寫與空白應被容忍
	req := httptest.NewRequest(http.MethodPost, "/login", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, req)

	if rec.Code != http.StatusSeeOther {
		t.Fatalf("POST /login（正確）狀態碼 = %d, 想要 303", rec.Code)
	}
	if loc := rec.Header().Get("Location"); loc != "/" {
		t.Errorf("登入成功應導向 /, 實際 %q", loc)
	}
	var cookie *http.Cookie
	for _, c := range rec.Result().Cookies() {
		if c.Name == auth.CookieName {
			cookie = c
		}
	}
	if cookie == nil {
		t.Fatal("登入成功應設定 session cookie")
	}

	// 帶著 session cookie 造訪首頁，應顯示帳號名稱而非登入連結。
	req = httptest.NewRequest(http.MethodGet, "/", nil)
	req.AddCookie(cookie)
	rec = httptest.NewRecorder()
	srv.ServeHTTP(rec, req)
	if rec.Code != http.StatusOK {
		t.Fatalf("GET /（已登入）狀態碼 = %d, 想要 200", rec.Code)
	}
	if body := rec.Body.String(); !strings.Contains(body, "示範帳號") {
		t.Error("已登入的首頁應顯示帳號名稱")
	}

	// 已登入者造訪 /login 應被導回首頁。
	req = httptest.NewRequest(http.MethodGet, "/login", nil)
	req.AddCookie(cookie)
	rec = httptest.NewRecorder()
	srv.ServeHTTP(rec, req)
	if rec.Code != http.StatusSeeOther {
		t.Errorf("GET /login（已登入）狀態碼 = %d, 想要 303", rec.Code)
	}

	// 登出後 cookie 失效，首頁不再顯示帳號。
	req = httptest.NewRequest(http.MethodPost, "/logout", nil)
	req.AddCookie(cookie)
	rec = httptest.NewRecorder()
	srv.ServeHTTP(rec, req)
	var cleared *http.Cookie
	for _, c := range rec.Result().Cookies() {
		if c.Name == auth.CookieName {
			cleared = c
		}
	}
	if cleared == nil || cleared.MaxAge >= 0 {
		t.Fatal("登出應清除 session cookie")
	}
	req = httptest.NewRequest(http.MethodGet, "/", nil)
	if cleared != nil {
		req.AddCookie(cleared)
	}
	rec = httptest.NewRecorder()
	srv.ServeHTTP(rec, req)
	if body := rec.Body.String(); strings.Contains(body, "示範帳號") {
		t.Error("登出後首頁不應顯示帳號名稱")
	}
}

func TestTamperedSessionRejected(t *testing.T) {
	srv := newTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.AddCookie(&http.Cookie{Name: auth.CookieName, Value: "1.9999999999.deadbeef"})
	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, req)

	if body := rec.Body.String(); strings.Contains(body, "示範帳號") {
		t.Error("偽造的 session 不應被接受")
	}
}

func TestStaticCSSServed(t *testing.T) {
	srv := newTestServer(t)

	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/static/css/app.css", nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("GET /static/css/app.css 狀態碼 = %d, 想要 200（記得先執行 make css）", rec.Code)
	}
}