WeKnora/internal/handler/auth.go

package handler

import (
	"context"
	"crypto/rand"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"

	"github.com/Tencent/WeKnora/internal/config"
	"github.com/Tencent/WeKnora/internal/errors"
	"github.com/Tencent/WeKnora/internal/logger"
	"github.com/Tencent/WeKnora/internal/types"
	"github.com/Tencent/WeKnora/internal/types/interfaces"
	secutils "github.com/Tencent/WeKnora/internal/utils"
)

// AuthHandler implements HTTP request handlers for user authentication
// Provides functionality for user registration, login, logout, and token management
// through the REST API endpoints
type AuthHandler struct {
	userService      interfaces.UserService
	tenantService    interfaces.TenantService
	configInfo       *config.Config
	systemSettingSvc interfaces.SystemSettingService
	// invitationSvc is required for the share-link registration path
	// (POST /auth/register-by-invite). When nil — e.g. legacy test
	// fixtures — the share-link endpoints respond 503 rather than
	// blocking the rest of the auth surface.
	invitationSvc interfaces.TenantInvitationService
}

// NewAuthHandler creates a new auth handler instance with the provided services
// Parameters:
//   - userService: An implementation of the UserService interface for business logic
//   - tenantService: An implementation of the TenantService interface for tenant management
//   - systemSettingSvc: 3-tier resolver for runtime-tunable settings such as
//     auth.registration_mode (P3). When DB has a row, it overrides cfg's
//     startup value; otherwise we fall back to cfg.Auth.RegistrationMode
//     (which already accounted for the legacy DISABLE_REGISTRATION env coerce
//     during config load). Mismatch impossible by construction since the
//     handler always passes cfg's value as the def parameter to GetString.
//
// Returns a pointer to the newly created AuthHandler
func NewAuthHandler(configInfo *config.Config,
	userService interfaces.UserService, tenantService interfaces.TenantService,
	systemSettingSvc interfaces.SystemSettingService,
	invitationSvc interfaces.TenantInvitationService,
) *AuthHandler {
	// Boot-time guard: a nil-or-empty Auth section silently disables the
	// invite_only gate (see Register below). Emit a loud one-shot log
	// pointing at the misconfiguration so operators notice on startup
	// instead of discovering it the day someone hits /auth/register.
	if configInfo == nil || configInfo.Auth == nil {
		logger.Errorf(context.Background(),
			"[auth] AuthHandler constructed with nil/incomplete config (cfg=%v); "+
				"registration_mode enforcement is disabled. This is almost certainly a wiring bug.",
			configInfo)
	}
	return &AuthHandler{
		configInfo:       configInfo,
		userService:      userService,
		tenantService:    tenantService,
		systemSettingSvc: systemSettingSvc,
		invitationSvc:    invitationSvc,
	}
}

// resolveRegistrationMode returns the currently active registration mode.
// Priority: DB system_settings > cfg (which already absorbed the legacy
// DISABLE_REGISTRATION env coerce at startup) > "self_serve" hard default.
//
// Centralised here so /auth/register and /auth/config stay in lock-step —
// otherwise a SystemAdmin's UI edit could affect one path and not the other.
func (h *AuthHandler) resolveRegistrationMode(ctx context.Context) string {
	// cfg-derived default: empty is impossible after applyAuthAndTenantDefaults,
	// but be defensive in case AuthHandler was constructed before that ran
	// (the NewAuthHandler guard already logged in that case).
	def := config.AuthRegistrationModeSelfServe
	if h.configInfo != nil && h.configInfo.Auth != nil {
		if m := strings.TrimSpace(h.configInfo.Auth.RegistrationMode); m != "" {
			def = m
		}
	}
	if h.systemSettingSvc == nil {
		return def
	}
	// envName = "" because DISABLE_REGISTRATION is a boolean and
	// auth.registration_mode is a string — the legacy env was already
	// coerced into `def` above. Mixing the two semantics at the resolver
	// layer would mean a UI delete (DB row absent) silently flipped to
	// the legacy boolean read again, which is surprising.
	return h.systemSettingSvc.GetString(ctx, "auth.registration_mode", "", def)
}

// Register godoc
// @Summary      用户注册
// @Description  注册新用户账号
// @Tags         认证
// @Accept       json
// @Produce      json
// @Param        request  body      types.RegisterRequest  true  "注册请求参数"
// @Success      201      {object}  types.RegisterResponse
// @Failure      400      {object}  errors.AppError  "请求参数错误"
// @Failure      403      {object}  errors.AppError  "注册功能已禁用"
// @Router       /auth/register [post]
func (h *AuthHandler) Register(c *gin.Context) {
	ctx := c.Request.Context()

	logger.Info(ctx, "Start user registration")

	// 当 auth.registration_mode=invite_only 时，public 注册被关闭。
	// 优先级：DB system_settings > cfg.Auth.RegistrationMode > "self_serve"。
	// SystemAdmin 通过「全局设置」UI 实时切换 self_serve / invite_only，立即
	// 生效，不需要重启服务。历史变量 DISABLE_REGISTRATION=true 仍在 config
	// 启动阶段被等价提升为 invite_only（applyAuthAndTenantDefaults），
	// 作为 cfg-default 进入 resolveRegistrationMode。
	if h.resolveRegistrationMode(ctx) == config.AuthRegistrationModeInviteOnly {
		logger.Warn(ctx, "Registration rejected: auth.registration_mode=invite_only")
		appErr := errors.NewForbiddenError("Registration is invite-only")
		c.Error(appErr)
		return
	}

	var req types.RegisterRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		logger.Error(ctx, "Failed to parse registration request parameters", err)
		appErr := errors.NewValidationError("Invalid registration parameters").WithDetails(err.Error())
		c.Error(appErr)
		return
	}
	req.Username = secutils.SanitizeForLog(req.Username)
	req.Email = secutils.SanitizeForLog(req.Email)
	req.Password = secutils.SanitizeForLog(req.Password)

	// Validate required fields
	if req.Username == "" || req.Email == "" || req.Password == "" {
		logger.Error(ctx, "Missing required registration fields")
		appErr := errors.NewValidationError("Username, email and password are required")
		c.Error(appErr)
		return
	}
	req.Username = secutils.SanitizeForLog(req.Username)
	req.Email = secutils.SanitizeForLog(req.Email)
	// Call service to register user
	user, err := h.userService.Register(ctx, &req)
	if err != nil {
		logger.Errorf(ctx, "Failed to register user: %v", err)
		appErr := errors.NewBadRequestError(err.Error())
		c.Error(appErr)
		return
	}

	// Return success response
	response := &types.RegisterResponse{
		Success: true,
		Message: "Registration successful",
		User:    user,
	}

	logger.Infof(ctx, "User registered successfully: %s", secutils.SanitizeForLog(user.Email))
	c.JSON(http.StatusCreated, response)
}

// Login godoc
// @Summary      用户登录
// @Description  用户登录并获取访问令牌
// @Tags         认证
// @Accept       json
// @Produce      json
// @Param        request  body      types.LoginRequest  true  "登录请求参数"
// @Success      200      {object}  types.LoginResponse
// @Failure      401      {object}  errors.AppError  "认证失败"
// @Router       /auth/login [post]
func (h *AuthHandler) Login(c *gin.Context) {
	ctx := c.Request.Context()

	logger.Info(ctx, "Start user login")

	var req types.LoginRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		logger.Error(ctx, "Failed to parse login request parameters", err)
		appErr := errors.NewValidationError("Invalid login parameters").WithDetails(err.Error())
		c.Error(appErr)
		return
	}
	email := secutils.SanitizeForLog(req.Email)

	// Validate required fields
	if req.Email == "" || req.Password == "" {
		logger.Error(ctx, "Missing required login fields")
		appErr := errors.NewValidationError("Email and password are required")
		c.Error(appErr)
		return
	}

	// Call service to authenticate user
	response, err := h.userService.Login(ctx, &req)
	if err != nil {
		logger.Errorf(ctx, "Failed to login user: %v", err)
		appErr := errors.NewUnauthorizedError("Login failed").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	// Check if login was successful
	if !response.Success {
		logger.Warnf(ctx, "Login failed: %s", response.Message)
		c.JSON(http.StatusUnauthorized, response)
		return
	}

	// User is already in the correct format from service

	logger.Infof(ctx, "User logged in successfully, email: %s", email)
	c.JSON(http.StatusOK, response)
}

// GetOIDCAuthorizationURL godoc
// @Summary      获取OIDC授权地址
// @Description  根据后端OIDC配置生成第三方登录跳转地址
// @Tags         认证
// @Accept       json
// @Produce      json
// @Param        redirect_uri  query     string  true  "OIDC回调地址"
// @Success      200           {object}  types.OIDCAuthURLResponse
// @Failure      400           {object}  errors.AppError  "请求参数错误"
// @Failure      403           {object}  errors.AppError  "OIDC未启用"
// @Router       /auth/oidc/url [get]
func (h *AuthHandler) GetOIDCAuthorizationURL(c *gin.Context) {
	ctx := c.Request.Context()
	redirectURI := strings.TrimSpace(c.Query("redirect_uri"))
	if redirectURI == "" {
		appErr := errors.NewValidationError("redirect_uri is required")
		c.Error(appErr)
		return
	}

	resp, err := h.userService.GetOIDCAuthorizationURL(ctx, redirectURI)
	if err != nil {
		logger.Errorf(ctx, "Failed to generate OIDC authorization URL: %v", err)
		appErr := errors.NewForbiddenError("OIDC authorization unavailable").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	c.JSON(http.StatusOK, resp)
}

// GetOIDCConfig godoc
// @Summary      获取OIDC登录配置
// @Description  返回OIDC是否启用以及provider展示名称，供前端决定是否展示OIDC登录入口
// @Tags         认证
// @Accept       json
// @Produce      json
// @Success      200  {object}  types.OIDCConfigResponse
// @Router       /auth/oidc/config [get]
func (h *AuthHandler) GetOIDCConfig(c *gin.Context) {
	providerDisplayName := ""
	enabled := false

	if h.configInfo != nil && h.configInfo.OIDCAuth != nil {
		enabled = h.configInfo.OIDCAuth.Enable
		providerDisplayName = strings.TrimSpace(h.configInfo.OIDCAuth.ProviderDisplayName)
	}

	c.JSON(http.StatusOK, &types.OIDCConfigResponse{
		Success:             true,
		Enabled:             enabled,
		ProviderDisplayName: providerDisplayName,
	})
}

// OIDCRedirectCallback godoc
// @Summary      OIDC登录重定向回调
// @Description  接收OIDC provider回调并由后端完成code交换，随后重定向回前端登录页
// @Tags         认证
// @Accept       json
// @Produce      json
// @Param        code   query string false "OIDC授权码"
// @Param        state  query string false "OIDC状态"
// @Param        error  query string false "OIDC错误码"
// @Success      302
// @Router       /auth/oidc/callback [get]
func (h *AuthHandler) OIDCRedirectCallback(c *gin.Context) {
	ctx := c.Request.Context()
	frontendRedirectURI := "/"

	if providerError := strings.TrimSpace(c.Query("error")); providerError != "" {
		redirectURL := frontendRedirectURI + "#oidc_error=" + urlQueryEscape(providerError)
		if description := strings.TrimSpace(c.Query("error_description")); description != "" {
			redirectURL += "&oidc_error_description=" + urlQueryEscape(description)
		}
		c.Redirect(http.StatusFound, redirectURL)
		return
	}

	state := strings.TrimSpace(c.Query("state"))
	decodedState, err := decodeOIDCState(state)
	if err != nil {
		logger.Errorf(ctx, "Failed to decode OIDC state: %v", err)
		c.Redirect(http.StatusFound, frontendRedirectURI+"#oidc_error="+urlQueryEscape("invalid_state"))
		return
	}

	code := strings.TrimSpace(c.Query("code"))
	if code == "" {
		c.Redirect(http.StatusFound, frontendRedirectURI+"#oidc_error="+urlQueryEscape("missing_code"))
		return
	}

	resp, err := h.userService.LoginWithOIDC(ctx, code, strings.TrimSpace(decodedState.RedirectURI))
	if err != nil {
		logger.Errorf(ctx, "Failed to complete OIDC login via redirect callback: %v", err)
		c.Redirect(http.StatusFound, frontendRedirectURI+"#oidc_error="+urlQueryEscape("login_failed")+"&oidc_error_description="+urlQueryEscape(err.Error()))
		return
	}
	if !resp.Success {
		c.Redirect(http.StatusFound, frontendRedirectURI+"#oidc_error="+urlQueryEscape("login_failed")+"&oidc_error_description="+urlQueryEscape(resp.Message))
		return
	}

	payload, err := encodeOIDCCallbackPayload(resp)
	if err != nil {
		logger.Errorf(ctx, "Failed to encode OIDC callback payload: %v", err)
		c.Redirect(http.StatusFound, frontendRedirectURI+"#oidc_error="+urlQueryEscape("payload_encode_failed"))
		return
	}

	c.Redirect(http.StatusFound, frontendRedirectURI+"#oidc_result="+urlQueryEscape(payload))
}

func encodeOIDCCallbackPayload(resp *types.OIDCCallbackResponse) (string, error) {
	payload, err := json.Marshal(resp)
	if err != nil {
		return "", err
	}
	return base64.RawURLEncoding.EncodeToString(payload), nil
}

type oidcStatePayload struct {
	Nonce       string `json:"nonce"`
	RedirectURI string `json:"redirect_uri,omitempty"`
}

func decodeOIDCState(raw string) (*oidcStatePayload, error) {
	decoded, err := base64.RawURLEncoding.DecodeString(strings.TrimSpace(raw))
	if err != nil {
		return nil, err
	}
	var payload oidcStatePayload
	if err := json.Unmarshal(decoded, &payload); err != nil {
		return nil, err
	}
	if strings.TrimSpace(payload.RedirectURI) == "" {
		return nil, errors.NewValidationError("state.redirect_uri is required")
	}
	return &payload, nil
}

func urlQueryEscape(value string) string {
	replacer := strings.NewReplacer(
		"%", "%25",
		" ", "%20",
		"#", "%23",
		"&", "%26",
		"+", "%2B",
		"=", "%3D",
		"?", "%3F",
	)
	return replacer.Replace(value)
}

// Logout godoc
// @Summary      用户登出
// @Description  撤销当前访问令牌并登出
// @Tags         认证
// @Accept       json
// @Produce      json
// @Success      200  {object}  map[string]interface{}  "登出成功"
// @Failure      400  {object}  errors.AppError         "请求参数错误"
// @Security     Bearer
// @Router       /auth/logout [post]
func (h *AuthHandler) Logout(c *gin.Context) {
	ctx := c.Request.Context()

	logger.Info(ctx, "Start user logout")

	// Extract token from Authorization header
	authHeader := c.GetHeader("Authorization")
	if authHeader == "" {
		logger.Error(ctx, "Missing Authorization header")
		appErr := errors.NewValidationError("Authorization header is required")
		c.Error(appErr)
		return
	}

	// Parse Bearer token
	tokenParts := strings.Split(authHeader, " ")
	if len(tokenParts) != 2 || tokenParts[0] != "Bearer" {
		logger.Error(ctx, "Invalid Authorization header format")
		appErr := errors.NewValidationError("Invalid Authorization header format")
		c.Error(appErr)
		return
	}

	token := tokenParts[1]

	// Revoke token
	err := h.userService.RevokeToken(ctx, token)
	if err != nil {
		logger.Errorf(ctx, "Failed to revoke token: %v", err)
		appErr := errors.NewInternalServerError("Logout failed").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	logger.Info(ctx, "User logged out successfully")
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "Logout successful",
	})
}

// RefreshToken godoc
// @Summary      刷新令牌
// @Description  使用刷新令牌获取新的访问令牌
// @Tags         认证
// @Accept       json
// @Produce      json
// @Param        request  body      object{refreshToken=string}  true  "刷新令牌"
// @Success      200      {object}  map[string]interface{}       "新令牌"
// @Failure      401      {object}  errors.AppError              "令牌无效"
// @Router       /auth/refresh [post]
func (h *AuthHandler) RefreshToken(c *gin.Context) {
	ctx := c.Request.Context()

	logger.Info(ctx, "Start token refresh")

	var req struct {
		RefreshToken string `json:"refreshToken" binding:"required"`
	}

	if err := c.ShouldBindJSON(&req); err != nil {
		logger.Error(ctx, "Failed to parse refresh token request", err)
		appErr := errors.NewValidationError("Invalid refresh token request").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	// Call service to refresh token
	accessToken, newRefreshToken, err := h.userService.RefreshToken(ctx, req.RefreshToken)
	if err != nil {
		logger.Errorf(ctx, "Failed to refresh token: %v", err)
		appErr := errors.NewUnauthorizedError("Token refresh failed").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	logger.Info(ctx, "Token refreshed successfully")
	c.JSON(http.StatusOK, gin.H{
		"success":       true,
		"message":       "Token refreshed successfully",
		"access_token":  accessToken,
		"refresh_token": newRefreshToken,
	})
}

// GetCurrentUser godoc
// @Summary      获取当前用户信息
// @Description  获取当前登录用户的详细信息
// @Tags         认证
// @Accept       json
// @Produce      json
// @Success      200  {object}  map[string]interface{}  "用户信息"
// @Failure      401  {object}  errors.AppError         "未授权"
// @Security     Bearer
// @Router       /auth/me [get]
func (h *AuthHandler) GetCurrentUser(c *gin.Context) {
	ctx := c.Request.Context()

	// Get current user from service (which extracts from context)
	user, err := h.userService.GetCurrentUser(ctx)
	if err != nil {
		logger.Errorf(ctx, "Failed to get current user: %v", err)
		appErr := errors.NewUnauthorizedError("Failed to get user information").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	// Get tenant information for the *active* tenant (the one the
	// auth middleware resolved against the X-Tenant-ID header), not
	// the user's home tenant. user.TenantID is the row stored on the
	// users table at signup time and never changes; reading it here
	// would make /auth/me always return the home tenant even after
	// the user switched into a peer tenant. The frontend then re-keys
	// `authStore.tenant.id` to the home tenant, and every UI gate
	// computed against it (currentTenantRole, isOwner, ...) leaks
	// the wrong role. Pull the active tenant id from context instead.
	var tenant *types.Tenant
	activeTenantID, _ := types.TenantIDFromContext(ctx)
	if activeTenantID == 0 {
		activeTenantID = user.TenantID
	}
	if activeTenantID > 0 {
		tenant, err = h.tenantService.GetTenantByID(ctx, activeTenantID)
		if err != nil {
			logger.Warnf(ctx, "Failed to get tenant info for user %s, tenant ID %d: %v", user.Email, activeTenantID, err)
			// Don't fail the request if tenant info is not available
		}
	}
	userInfo := user.ToUserInfo()
	userInfo.CanAccessAllTenants = user.CanAccessAllTenants && h.configInfo.Tenant.EnableCrossTenantAccess
	// 同步返回当前用户的 memberships，让前端在页面刷新（仅命中 /auth/me）
	// 后也能恢复 currentTenantRole，避免角色信息只在 login 那一刻可用。
	memberships := h.userService.BuildLoginMemberships(ctx, user, tenant)
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"data": gin.H{
			"user":        userInfo,
			"tenant":      tenant,
			"memberships": memberships,
		},
	})
}

// updateMyPreferencesRequest is the body for PUT /auth/me/preferences.
// Fields are pointers so the handler can distinguish "key not present"
// (preserve existing value) from "explicit false". See
// types.UserPreferences for the persistence-layer counterpart.
type updateMyPreferencesRequest struct {
	EnableMemory *bool `json:"enable_memory"`
	// LastActiveTenantID lets the SPA persist "after a fresh login,
	// drop me back into this workspace" across devices. Send a positive
	// tenant id to set / replace, or 0 to clear. Membership is validated
	// at next login, not here. Nil = field omitted from the PATCH and
	// stays untouched.
	LastActiveTenantID *uint64 `json:"last_active_tenant_id"`
}

// UpdateMyPreferences godoc
// @Summary      更新当前用户的个性化设置
// @Description  按 PATCH 语义合并用户偏好（仅覆盖请求体里出现的字段，其余字段保持不变），
// @Description  数据存放在 users.preferences (JSON)，跨设备/浏览器自动同步。
// @Tags         认证
// @Accept       json
// @Produce      json
// @Param        request  body      updateMyPreferencesRequest  true  "Preferences patch"
// @Success      200      {object}  map[string]interface{}      "更新后的偏好"
// @Failure      400      {object}  errors.AppError             "请求参数错误"
// @Failure      401      {object}  errors.AppError             "未授权"
// @Security     Bearer
// @Router       /auth/me/preferences [put]
func (h *AuthHandler) UpdateMyPreferences(c *gin.Context) {
	ctx := c.Request.Context()

	user, err := h.userService.GetCurrentUser(ctx)
	if err != nil {
		appErr := errors.NewUnauthorizedError("Failed to get user information").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	var req updateMyPreferencesRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		appErr := errors.NewValidationError("Invalid preferences request").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	patch := types.UserPreferences{
		EnableMemory:       req.EnableMemory,
		LastActiveTenantID: req.LastActiveTenantID,
	}
	prefs, err := h.userService.UpdateUserPreferences(ctx, user.ID, patch)
	if err != nil {
		logger.Errorf(ctx, "Failed to update preferences for user %s: %v", user.Email, err)
		appErr := errors.NewBadRequestError("Failed to update preferences").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"data":    prefs,
	})
}

// ChangePassword godoc
// @Summary      修改密码
// @Description  修改当前用户的登录密码
// @Tags         认证
// @Accept       json
// @Produce      json
// @Param        request  body      object{old_password=string,new_password=string}  true  "密码修改请求"
// @Success      200      {object}  map[string]interface{}                           "修改成功"
// @Failure      400      {object}  errors.AppError                                  "请求参数错误"
// @Security     Bearer
// @Router       /auth/change-password [post]
func (h *AuthHandler) ChangePassword(c *gin.Context) {
	ctx := c.Request.Context()

	logger.Info(ctx, "Start password change")

	var req struct {
		OldPassword string `json:"old_password" binding:"required"`
		NewPassword string `json:"new_password" binding:"required,min=6"`
	}

	if err := c.ShouldBindJSON(&req); err != nil {
		logger.Error(ctx, "Failed to parse password change request", err)
		appErr := errors.NewValidationError("Invalid password change request").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	// Get current user
	user, err := h.userService.GetCurrentUser(ctx)
	if err != nil {
		logger.Errorf(ctx, "Failed to get current user: %v", err)
		appErr := errors.NewUnauthorizedError("Failed to get user information").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	// Change password
	err = h.userService.ChangePassword(ctx, user.ID, req.OldPassword, req.NewPassword)
	if err != nil {
		logger.Errorf(ctx, "Failed to change password: %v", err)
		appErr := errors.NewBadRequestError("Password change failed").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	logger.Infof(ctx, "Password changed successfully for user: %s", user.Email)
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "Password changed successfully",
	})
}

// GetAuthConfig godoc
// @Summary      获取认证配置
// @Description  返回当前部署的注册模式等公开认证配置，供前端决定是否展示注册入口
// @Tags         认证
// @Accept       json
// @Produce      json
// @Success      200  {object}  map[string]interface{}  "认证配置"
// @Router       /auth/config [get]
//
// GetAuthConfig is intentionally a no-auth endpoint: the frontend reads
// it on app load to decide whether to show the Register tab. We expose
// only what the UI strictly needs (registration_mode); other config
// stays internal.
func (h *AuthHandler) GetAuthConfig(c *gin.Context) {
	// Same source-of-truth as Register's gate, so the UI hide-the-button
	// signal can never disagree with the API enforcement signal.
	mode := h.resolveRegistrationMode(c.Request.Context())
	c.JSON(http.StatusOK, gin.H{
		"success":           true,
		"registration_mode": mode,
	})
}

// SwitchTenant godoc
// @Summary      切换激活租户
// @Description  为当前用户在目标租户重新签发访问令牌；要求该用户在目标租户存在 active 成员关系
// @Tags         认证
// @Accept       json
// @Produce      json
// @Param        request  body      object{tenant_id=integer,refresh_token=string}  true  "切换请求"
// @Success      200      {object}  types.LoginResponse
// @Failure      400      {object}  errors.AppError  "参数错误"
// @Failure      403      {object}  errors.AppError  "无该租户成员关系"
// @Security     Bearer
// @Router       /auth/switch-tenant [post]
//
// SwitchTenant is the v1 backend hook for the tenant-switcher UI added
// in PR 3. The current PR ships the endpoint so multi-tenant tests can
// exercise the membership flow end-to-end before the frontend lands.
func (h *AuthHandler) SwitchTenant(c *gin.Context) {
	ctx := c.Request.Context()

	var req struct {
		TenantID     uint64 `json:"tenant_id"     binding:"required"`
		RefreshToken string `json:"refresh_token"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		appErr := errors.NewValidationError("Invalid switch-tenant request").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	user, err := h.userService.GetCurrentUser(ctx)
	if err != nil || user == nil {
		appErr := errors.NewUnauthorizedError("not authenticated")
		c.Error(appErr)
		return
	}

	resp, err := h.userService.SwitchTenant(ctx, user, req.TenantID, req.RefreshToken)
	if err != nil {
		logger.Errorf(ctx, "SwitchTenant failed user=%s target=%d: %v", user.ID, req.TenantID, err)
		appErr := errors.NewForbiddenError("switch tenant failed").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	c.JSON(http.StatusOK, resp)
}

// AutoSetup godoc
// @Summary      自动初始化（Lite 桌面版）
// @Description  Lite 版专用：首次启动时自动创建默认用户和租户并返回令牌，后续启动直接签发令牌，免除手动注册/登录流程
// @Tags         认证
// @Accept       json
// @Produce      json
// @Success      200  {object}  types.LoginResponse
// @Failure      403  {object}  errors.AppError  "非 Lite 版本"
// @Router       /auth/auto-setup [post]
func (h *AuthHandler) AutoSetup(c *gin.Context) {
	ctx := c.Request.Context()

	if Edition != "lite" {
		appErr := errors.NewForbiddenError("auto-setup is only available in lite edition")
		c.Error(appErr)
		return
	}

	const defaultEmail = "admin@weknora.local"

	user, _ := h.userService.GetUserByEmail(ctx, defaultEmail)
	if user == nil {
		logger.Info(ctx, "Auto-setup: creating default user and tenant for lite edition")

		randomBytes := make([]byte, 24)
		if _, err := rand.Read(randomBytes); err != nil {
			appErr := errors.NewInternalServerError("auto-setup failed: unable to generate credentials")
			c.Error(appErr)
			return
		}
		randomPassword := base64.RawURLEncoding.EncodeToString(randomBytes)
		randomUsername := fmt.Sprintf("user_%s", base64.RawURLEncoding.EncodeToString(randomBytes[:6]))

		_, err := h.userService.Register(ctx, &types.RegisterRequest{
			Username: randomUsername,
			Email:    defaultEmail,
			Password: randomPassword,
		})
		if err != nil {
			logger.Errorf(ctx, "Auto-setup: failed to register default user: %v", err)
			appErr := errors.NewInternalServerError("auto-setup failed").WithDetails(err.Error())
			c.Error(appErr)
			return
		}
		user, _ = h.userService.GetUserByEmail(ctx, defaultEmail)
		if user == nil {
			appErr := errors.NewInternalServerError("auto-setup failed: user not found after registration")
			c.Error(appErr)
			return
		}
	}

	accessToken, refreshToken, err := h.userService.GenerateTokens(ctx, user)
	if err != nil {
		logger.Errorf(ctx, "Auto-setup: failed to generate tokens: %v", err)
		appErr := errors.NewInternalServerError("auto-setup failed").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	tenant, _ := h.tenantService.GetTenantByID(ctx, user.TenantID)

	logger.Info(ctx, "Auto-setup: completed successfully")
	c.JSON(http.StatusOK, &types.LoginResponse{
		Success:      true,
		Message:      "Auto-setup successful",
		User:         user,
		ActiveTenant: tenant,
		Memberships: []types.Membership{{
			TenantID:   user.TenantID,
			TenantName: tenantNameOrEmpty(tenant),
			Role:       types.TenantRoleOwner,
		}},
		Token:        accessToken,
		RefreshToken: refreshToken,
	})
}

// tenantNameOrEmpty returns t.Name when t is non-nil, "" otherwise.
// Used by AutoSetup to populate Membership.TenantName without crashing
// if the tenant lookup failed.
func tenantNameOrEmpty(t *types.Tenant) string {
	if t == nil {
		return ""
	}
	return t.Name
}

// ValidateToken godoc
// @Summary      验证令牌
// @Description  验证访问令牌是否有效
// @Tags         认证
// @Accept       json
// @Produce      json
// @Success      200  {object}  map[string]interface{}  "令牌有效"
// @Failure      401  {object}  errors.AppError         "令牌无效"
// @Security     Bearer
// @Router       /auth/validate [get]
func (h *AuthHandler) ValidateToken(c *gin.Context) {
	ctx := c.Request.Context()

	logger.Info(ctx, "Start token validation")

	// Extract token from Authorization header
	authHeader := c.GetHeader("Authorization")
	if authHeader == "" {
		logger.Error(ctx, "Missing Authorization header")
		appErr := errors.NewValidationError("Authorization header is required")
		c.Error(appErr)
		return
	}

	// Parse Bearer token
	tokenParts := strings.Split(authHeader, " ")
	if len(tokenParts) != 2 || tokenParts[0] != "Bearer" {
		logger.Error(ctx, "Invalid Authorization header format")
		appErr := errors.NewValidationError("Invalid Authorization header format")
		c.Error(appErr)
		return
	}

	token := tokenParts[1]

	// Validate token
	user, _, err := h.userService.ValidateToken(ctx, token)
	if err != nil {
		logger.Errorf(ctx, "Failed to validate token: %v", err)
		appErr := errors.NewUnauthorizedError("Token validation failed").WithDetails(err.Error())
		c.Error(appErr)
		return
	}

	logger.Infof(ctx, "Token validated successfully for user: %s", user.Email)
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "Token is valid",
		"user":    user.ToUserInfo(),
	})
}