package handlers

import (
	"fmt"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"

	"github.com/gin-gonic/gin"

	"go_blog/models"
)

// postForm 是表单编码请求的小助手，始终携带 CSRF 令牌。
func postForm(e *securityTestEnv, method, path, cookie, csrfToken string, fields url.Values) *httptest.ResponseRecorder {
	if fields == nil {
		fields = url.Values{}
	}
	if csrfToken != "" {
		fields.Set("_csrf", csrfToken)
	}
	return e.do(method, path, cookie, strings.NewReader(fields.Encode()), "application/x-www-form-urlencoded")
}

// TestStorageDirTraversalRejected 覆盖 SECURITY_TODO #22：管理员不得将
// storage_dir 设置为逃逸出存储根目录的值。
func TestStorageDirTraversalRejected(t *testing.T) {
	e := newSecurityTestEnv(t)
	admin := e.login(t, "admin")
	token := e.csrfTokenFor(t, admin)

	cases := []string{
		"../evil",
		"foo/bar",
		"a\\b",
		"/abs/path",
		"..",
		".",
	}
	for _, dir := range cases {
		w := postJSON(e, http.MethodPost, "/api/admin/settings/upload", admin, token,
			gin.H{"action": "save_config", "storage_dir": dir})
		if w.Code != http.StatusBadRequest || respCode(w) != "settings_upload_illegal_dir" {
			t.Fatalf("storage_dir %q: status = %d, code = %q, want 400/settings_upload_illegal_dir",
				dir, w.Code, respCode(w))
		}
		// 存储的值必须保持不变。
		var u models.UploadConfig
		if err := e.db.First(&u, 1).Error; err != nil {
			t.Fatalf("load upload config: %v", err)
		}
		if u.StorageDir != "attachments" {
			t.Fatalf("storage_dir %q: persisted value = %q, want unchanged \"attachments\"", dir, u.StorageDir)
		}
	}

	// 安全的单段值可被接受。
	w := postJSON(e, http.MethodPost, "/api/admin/settings/upload", admin, token,
		gin.H{"action": "save_config", "storage_dir": "my_attach-2"})
	if w.Code != http.StatusOK || !respOK(w) {
		t.Fatalf("safe storage_dir: status = %d, body %s", w.Code, w.Body.String())
	}
	var u models.UploadConfig
	if err := e.db.First(&u, 1).Error; err != nil {
		t.Fatalf("load upload config: %v", err)
	}
	if u.StorageDir != "my_attach-2" {
		t.Fatalf("persisted storage_dir = %q, want my_attach-2", u.StorageDir)
	}
}

// TestProfilePasswordMinLength 覆盖个人资料密码修改路径上的
// SECURITY_TODO #23。
func TestProfilePasswordMinLength(t *testing.T) {
	e := newSecurityTestEnv(t)
	alice := e.login(t, "alice")
	token := e.csrfTokenFor(t, alice)

	// 1 个字符的密码必须被拒绝，旧哈希保持不变。
	w := postJSON(e, http.MethodPost, "/api/profile", alice, token,
		gin.H{"current_password": "pw-alice", "new_password": "a"})
	if w.Code != http.StatusBadRequest || respCode(w) != "profile_password_short" {
		t.Fatalf("short password: status = %d, code = %q, want 400/profile_password_short",
			w.Code, respCode(w))
	}
	var u models.User
	if err := e.db.Where("username = ?", "alice").First(&u).Error; err != nil {
		t.Fatalf("load alice: %v", err)
	}
	if !u.CheckPassword("pw-alice") {
		t.Fatal("old password no longer verifies after rejected change")
	}

	// 6 个字符的密码可被接受。
	w = postJSON(e, http.MethodPost, "/api/profile", alice, token,
		gin.H{"current_password": "pw-alice", "new_password": "newpass6"})
	if w.Code != http.StatusOK || !respOK(w) {
		t.Fatalf("valid password change: status = %d, body %s", w.Code, w.Body.String())
	}
	if err := e.db.Where("username = ?", "alice").First(&u).Error; err != nil {
		t.Fatalf("reload alice: %v", err)
	}
	if !u.CheckPassword("newpass6") || u.CheckPassword("pw-alice") {
		t.Fatal("password change did not take effect")
	}
}

// TestProfileEmailValidation 覆盖个人资料路径上的 SECURITY_TODO #24。
func TestProfileEmailValidation(t *testing.T) {
	e := newSecurityTestEnv(t)
	alice := e.login(t, "alice")
	token := e.csrfTokenFor(t, alice)

	w := postJSON(e, http.MethodPost, "/api/profile", alice, token,
		gin.H{"email": "not-an-email"})
	if w.Code != http.StatusBadRequest || respCode(w) != "profile_email_invalid" {
		t.Fatalf("invalid email: status = %d, code = %q", w.Code, respCode(w))
	}
	var u models.User
	if err := e.db.Where("username = ?", "alice").First(&u).Error; err != nil {
		t.Fatalf("load alice: %v", err)
	}
	if u.Email != "" {
		t.Fatalf("invalid email was persisted: %q", u.Email)
	}

	w = postJSON(e, http.MethodPost, "/api/profile", alice, token,
		gin.H{"email": "alice@example.com"})
	if w.Code != http.StatusOK || !respOK(w) {
		t.Fatalf("valid email: status = %d, body %s", w.Code, w.Body.String())
	}
	if err := e.db.Where("username = ?", "alice").First(&u).Error; err != nil {
		t.Fatalf("reload alice: %v", err)
	}
	if u.Email != "alice@example.com" {
		t.Fatalf("valid email not persisted: %q", u.Email)
	}
}

// TestAdminUserPasswordAndEmailEnforcement 覆盖后台用户创建/更新路径上的
// SECURITY_TODO #23/#24。
func TestAdminUserPasswordAndEmailEnforcement(t *testing.T) {
	e := newSecurityTestEnv(t)
	admin := e.login(t, "admin")
	token := e.csrfTokenFor(t, admin)

	// 创建：短密码被拒绝（不创建任何行）。
	create := gin.H{"username": "charlie", "password": "ab", "role": models.RoleAuthor}
	w := postJSON(e, http.MethodPost, "/api/admin/users", admin, token, create)
	if w.Code != http.StatusBadRequest || respCode(w) != "user_password_short" {
		t.Fatalf("create with short password: status = %d, code = %q, want 400/user_password_short",
			w.Code, respCode(w))
	}

	// 创建：非法邮箱被拒绝。
	create["password"] = "longenough"
	create["email"] = "abc"
	w = postJSON(e, http.MethodPost, "/api/admin/users", admin, token, create)
	if w.Code != http.StatusBadRequest || respCode(w) != "user_email_invalid" {
		t.Fatalf("create with invalid email: status = %d, code = %q", w.Code, respCode(w))
	}

	var count int64
	e.db.Model(&models.User{}).Where("username = ?", "charlie").Count(&count)
	if count != 0 {
		t.Fatal("charlie was created despite invalid input")
	}

	// 创建：合法数据成功。
	create["email"] = "charlie@example.com"
	w = postJSON(e, http.MethodPost, "/api/admin/users", admin, token, create)
	if w.Code != http.StatusOK || !respOK(w) {
		t.Fatalf("create valid user: status = %d, body %s", w.Code, w.Body.String())
	}
	e.db.Model(&models.User{}).Where("username = ?", "charlie").Count(&count)
	if count != 1 {
		t.Fatal("charlie was not created")
	}

	// 更新（密码重置路径）：短密码被拒绝，哈希保持不变。
	aliceID := userIDByUsername(t, e.db, "alice")
	w = postJSON(e, http.MethodPut, fmt.Sprintf("/api/admin/users/%d", aliceID), admin, token,
		gin.H{"password": "x", "role": models.RoleAuthor})
	if w.Code != http.StatusBadRequest || respCode(w) != "user_password_short" {
		t.Fatalf("update with short password: status = %d, code = %q", w.Code, respCode(w))
	}
	var u models.User
	if err := e.db.Where("username = ?", "alice").First(&u).Error; err != nil {
		t.Fatalf("load alice: %v", err)
	}
	if !u.CheckPassword("pw-alice") {
		t.Fatal("alice password changed by a rejected reset")
	}

	// 更新：非法邮箱被拒绝，旧值保留。
	w = postJSON(e, http.MethodPut, fmt.Sprintf("/api/admin/users/%d", aliceID), admin, token,
		gin.H{"email": "bad", "role": models.RoleAuthor})
	if w.Code != http.StatusBadRequest || respCode(w) != "user_email_invalid" {
		t.Fatalf("update with invalid email: status = %d, code = %q", w.Code, respCode(w))
	}
	e.db.Where("username = ?", "alice").First(&u)
	if u.Email != "" {
		t.Fatalf("invalid admin-set email persisted: %q", u.Email)
	}
}

// TestRegisterRejectsInvalidEmail 覆盖注册上的 SECURITY_TODO #24。
func TestRegisterRejectsInvalidEmail(t *testing.T) {
	e := newSecurityTestEnv(t)
	if err := e.db.Model(&models.SiteSetting{}).Where("id = ?", 1).Update("allow_registration", true).Error; err != nil {
		t.Fatalf("enable registration: %v", err)
	}

	// 获取注册表单以获得匿名 CSRF 令牌 + 会话。
	req := httptest.NewRequest(http.MethodGet, "/register", nil)
	w := httptest.NewRecorder()
	e.router.ServeHTTP(w, req)
	if w.Code != http.StatusOK {
		t.Fatalf("GET /register: status = %d", w.Code)
	}
	m := csrfTokenRe.FindStringSubmatch(w.Body.String())
	if m == nil {
		t.Fatal("register page did not render a CSRF token")
	}
	anonCookie := e.sessionCookie(w)

	fields := gin.H{
		"username":         "carol",
		"password":         "secret1",
		"confirm_password": "secret1",
		"email":            "abc",
	}
	w2 := postJSON(e, http.MethodPost, "/api/auth/register", anonCookie, m[1], fields)
	if w2.Code != http.StatusBadRequest {
		t.Fatalf("register invalid email: status = %d, want 400", w2.Code)
	}
	if code := respCode(w2); code != "register_email_invalid" {
		t.Fatalf("register invalid email: code = %q, want register_email_invalid", code)
	}
	var count int64
	e.db.Model(&models.User{}).Where("username = ?", "carol").Count(&count)
	if count != 0 {
		t.Fatal("carol created with invalid email")
	}

	fields["email"] = "carol@example.com"
	w2 = postJSON(e, http.MethodPost, "/api/auth/register", anonCookie, m[1], fields)
	if w2.Code != http.StatusOK || !respOK(w2) {
		t.Fatalf("register valid email: status = %d, body %s", w2.Code, w2.Body.String())
	}
	e.db.Model(&models.User{}).Where("username = ?", "carol").Count(&count)
	if count != 1 {
		t.Fatal("carol not created")
	}
}

// limiterEntryKey 通过扫描已跟踪条目返回某用户名的限流器键
// （前缀的客户端 IP 取决于测试传输方式）。
func limiterEntryKey(e *securityTestEnv, username string) string {
	for k := range e.limiter.entries {
		if strings.HasSuffix(k, "\x00"+username) {
			return k
		}
	}
	return ""
}

// TestLoginRateLimited 覆盖 SECURITY_TODO #10：重复失败会锁定
// IP+用户名键，成功登录后重置。
func TestLoginRateLimited(t *testing.T) {
	e := newSecurityTestEnv(t)

	loginAttempt := func(body gin.H) (*httptest.ResponseRecorder, string) {
		// 每次尝试使用全新的匿名会话（和 CSRF 令牌）。
		req := httptest.NewRequest(http.MethodGet, "/login", nil)
		w := httptest.NewRecorder()
		e.router.ServeHTTP(w, req)
		m := csrfTokenRe.FindStringSubmatch(w.Body.String())
		if m == nil {
			t.Fatal("login page did not render a CSRF token")
		}
		anonCookie := e.sessionCookie(w)
		w2 := postJSON(e, http.MethodPost, "/api/auth/login", anonCookie, m[1], body)
		return w2, anonCookie
	}

	bad := gin.H{"username": "alice", "password": "wrong-password"}
	for i := 0; i < maxLoginFailures; i++ {
		w, _ := loginAttempt(bad)
		if w.Code != http.StatusUnauthorized {
			t.Fatalf("attempt %d: status = %d, want 401", i+1, w.Code)
		}
		if code := respCode(w); code != "login_error" {
			t.Fatalf("attempt %d: code = %q, want login_error", i+1, code)
		}
	}

	// 下一次尝试（即使密码正确）也会被锁定。
	good := gin.H{"username": "alice", "password": "pw-alice"}
	w, _ := loginAttempt(good)
	if w.Code != http.StatusTooManyRequests {
		t.Fatalf("locked attempt: status = %d, want 429", w.Code)
	}
	if code := respCode(w); code != "login_locked" {
		t.Fatalf("locked attempt: code = %q, want login_locked", code)
	}

	// 不同的键（用户名）不受影响。
	w, _ = loginAttempt(gin.H{"username": "bob", "password": "pw-bob"})
	if w.Code != http.StatusOK || respRedirect(w) != "/" {
		t.Fatalf("different user login during lock: status = %d, redirect = %q",
			w.Code, respRedirect(w))
	}

	// 重置后，被锁定的键再次可用。
	aliceKey := limiterEntryKey(e, "alice")
	if aliceKey == "" {
		t.Fatal("alice rate-limit entry not found")
	}
	e.limiter.Reset(aliceKey)
	w, _ = loginAttempt(good)
	if w.Code != http.StatusOK || respRedirect(w) != "/" {
		t.Fatalf("login after reset: status = %d, redirect = %q",
			w.Code, respRedirect(w))
	}
}

// TestLoginTimingDoesNotRevealUser 断言 SECURITY_TODO #25 的结构性保证：
// 未知用户名仍执行一次 bcrypt 比较（虚拟哈希）并记录一次失败，
// 因此两个分支在设计上耗时不可区分。
func TestLoginTimingDoesNotRevealUser(t *testing.T) {
	e := newSecurityTestEnv(t)

	req := httptest.NewRequest(http.MethodGet, "/login", nil)
	w := httptest.NewRecorder()
	e.router.ServeHTTP(w, req)
	m := csrfTokenRe.FindStringSubmatch(w.Body.String())
	if m == nil {
		t.Fatal("login page did not render a CSRF token")
	}
	anonCookie := e.sessionCookie(w)

	w2 := postJSON(e, http.MethodPost, "/api/auth/login", anonCookie, m[1],
		gin.H{"username": "does-not-exist-31415", "password": "anything"})
	if w2.Code != http.StatusUnauthorized || respCode(w2) != "login_error" {
		t.Fatalf("unknown user: status = %d, code = %q", w2.Code, respCode(w2))
	}

	// 未知用户的键必须被计入失败次数（若限流器共享），
	// 证明该分支走过了 Fail + 虚拟 bcrypt 路径。
	if key := limiterEntryKey(e, "does-not-exist-31415"); key == "" {
		t.Fatal("unknown-user branch did not record a failure")
	} else if e.limiter.entries[key].failures != 1 {
		t.Fatalf("unknown-user failure count = %d, want 1", e.limiter.entries[key].failures)
	}
}
func TestSafeStorageDirNameAndValidators(t *testing.T) {
	for _, tc := range []struct {
		dir string
		ok  bool
	}{
		{"attachments", true},
		{"my_attach-2", true},
		{"A1-_", true},
		{"", false},
		{"../evil", false},
		{"foo/bar", false},
		{"a\\b", false},
		{"/abs", false},
		{"..", false},
		{"a b", false},
		{".hidden", false},
	} {
		if got := safeStorageDirName(tc.dir); got != tc.ok {
			t.Errorf("safeStorageDirName(%q) = %v, want %v", tc.dir, got, tc.ok)
		}
	}

	if validatePassword("12345") {
		t.Error("validatePassword accepted 5 chars")
	}
	if !validatePassword("123456") {
		t.Error("validatePassword rejected 6 chars")
	}
	if !validateEmail("") || !validateEmail("user@example.com") {
		t.Error("validateEmail rejected empty or valid address")
	}
	if validateEmail("abc") || validateEmail("a@b@c") {
		t.Error("validateEmail accepted malformed address")
	}
}