package main

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

func TestLoginRequestValidate(t *testing.T) {
	tests := []struct {
		name    string
		in      loginRequest
		wantErr string // 空字串表示應通過
	}{
		{"最小欄位", loginRequest{Username: "alice", Password: "sup3r-secret"}, ""},
		{"username 帶首尾空白", loginRequest{Username: " alice ", Password: "sup3r-secret"}, ""},
		{"缺 username", loginRequest{Password: "sup3r-secret"}, "username"},
		{"username 僅空白", loginRequest{Username: "   ", Password: "sup3r-secret"}, "username"},
		{"缺 password", loginRequest{Username: "alice"}, "password"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := tt.in.validate()
			if tt.wantErr == "" {
				if err != nil {
					t.Fatalf("validate() = %v, want nil", err)
				}
				return
			}
			if err == nil || !strings.Contains(err.Error(), tt.wantErr) {
				t.Fatalf("validate() = %v, want error containing %q", err, tt.wantErr)
			}
		})
	}
}

func TestLoginRequestValidateTrimsUsername(t *testing.T) {
	in := loginRequest{Username: "  alice\t", Password: "sup3r-secret"}
	if err := in.validate(); err != nil {
		t.Fatal("validate: ", err)
	}
	if in.Username != "alice" {
		t.Fatalf("validate 後 username = %q, want %q", in.Username, "alice")
	}
}

func TestNewRandomToken(t *testing.T) {
	for _, n := range []int{16, 32} {
		wantLen := (n*8 + 5) / 6 // base64url 無填充的編碼長度
		seen := make(map[string]bool)
		for i := 0; i < 100; i++ {
			token, err := newRandomToken(n)
			if err != nil {
				t.Fatal("newRandomToken: ", err)
			}
			if len(token) != wantLen {
				t.Fatalf("n=%d token 長度 = %d, want %d", n, len(token), wantLen)
			}
			if seen[token] {
				t.Fatalf("n=%d token 重複: %s", n, token)
			}
			seen[token] = true
		}
	}
}

// 無效請求應在查詢資料庫前就回應,因此 handler 可以傳入 nil db 進行測試。
func TestLoginHandlerRejectsInvalidInput(t *testing.T) {
	h := loginHandler(nil)
	plainReq := httptest.NewRequest(http.MethodPost, "/login",
		strings.NewReader(`{"username":"alice","password":"sup3r-secret"}`))
	jsonReq := func(body string) *http.Request {
		req := httptest.NewRequest(http.MethodPost, "/login", strings.NewReader(body))
		req.Header.Set("Content-Type", "application/json")
		return req
	}
	tests := []struct {
		name       string
		req        *http.Request
		wantStatus int
	}{
		{"Content-Type 非 JSON", plainReq, http.StatusUnsupportedMediaType},
		{"JSON 格式錯誤", jsonReq(`{username:`), http.StatusBadRequest},
		{"缺 username", jsonReq(`{"password":"sup3r-secret"}`), http.StatusBadRequest},
		{"缺 password", jsonReq(`{"username":"alice"}`), http.StatusBadRequest},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			rec := httptest.NewRecorder()
			h(rec, tt.req)
			if rec.Code != tt.wantStatus {
				t.Fatalf("status = %d, want %d, body = %s", rec.Code, tt.wantStatus, rec.Body.String())
			}
			if ct := rec.Header().Get("Content-Type"); !strings.Contains(ct, "application/json") {
				t.Fatalf("Content-Type = %q, want application/json", ct)
			}
			if !strings.Contains(rec.Body.String(), `"error"`) {
				t.Fatalf("回應應為 JSON error 格式: %s", rec.Body.String())
			}
		})
	}
}

func TestNewPublicUserOmitsPasswordHash(t *testing.T) {
	u := &User{ID: 7, Username: "alice", Email: "alice@example.com", Name: "Alice", Role: RoleAdmin, PasswordHash: "$argon2id$secret"}
	pu := newPublicUser(u)
	if pu.ID != 7 || pu.Username != "alice" || pu.Email != "alice@example.com" || pu.Name != "Alice" || pu.Role != RoleAdmin {
		t.Fatalf("newPublicUser() = %+v, 欄位不符", pu)
	}
	b, err := json.Marshal(pu)
	if err != nil {
		t.Fatal(err)
	}
	if strings.Contains(string(b), "argon2") {
		t.Fatalf("回應不得含密碼雜湊: %s", b)
	}
}

// 表單登入成功後以 303 導向帳號首頁 /，而非停留在 /login。
func TestLoginHandlerFormSuccessRedirectsHome(t *testing.T) {
	db, err := openDB()
	if err != nil {
		t.Skipf("資料庫不可用，略過整合測試: %v", err)
	}
	suffix, err := newRandomToken(6)
	if err != nil {
		t.Fatal(err)
	}
	u := &User{Username: "login-" + suffix, Email: "login-" + suffix + "@example.com", Name: "Login Test"}
	if err := u.SetPassword("sup3r-secret"); err != nil {
		t.Fatal(err)
	}
	if err := db.Create(u).Error; err != nil {
		t.Fatalf("create user: %v", err)
	}
	t.Cleanup(func() {
		db.Delete(&Session{}, "user_id = ?", u.ID)
		db.Delete(&User{}, u.ID)
	})

	body := "csrf_token=token-A&username=" + u.Username + "&password=sup3r-secret"
	req := formPost(body, &http.Cookie{Name: csrfCookieName, Value: "token-A"})
	rec := httptest.NewRecorder()
	loginHandler(db)(rec, req)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status = %d, want 303, body = %s", rec.Code, rec.Body.String())
	}
	if loc := rec.Header().Get("Location"); loc != "/" {
		t.Fatalf("Location = %q, want /", loc)
	}
	if !strings.Contains(rec.Header().Get("Set-Cookie"), sessionCookieName) {
		t.Fatalf("登入成功應設定 Session Cookie, Set-Cookie = %v", rec.Header().Values("Set-Cookie"))
	}
}