// Package controller 定义 MVC 架构中的 Controller 层。
package controller

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strings"

	"stock-analysis/internal/model"
	"stock-analysis/internal/service"
)

// AuthController 提供用户认证相关的 HTTP 接口。
type AuthController struct {
	svc *service.AuthService
}

// NewAuthController 创建认证控制器。
func NewAuthController(svc *service.AuthService) *AuthController {
	return &AuthController{svc: svc}
}

// CurrentUser 返回当前请求对应的登录用户，未登录返回错误。
func (c *AuthController) CurrentUser(r *http.Request) (*model.User, error) {
	token := extractToken(r)
	if token == "" {
		return nil, fmt.Errorf("未登录")
	}
	return c.svc.ValidateToken(r.Context(), token)
}

// sendCodeRequest 发送验证码请求。
type sendCodeRequest struct {
	Email   string `json:"email"`
	Purpose string `json:"purpose"` // register 或 login
}

// SendCode 处理 POST /api/auth/send-code，发送邮箱验证码。
func (c *AuthController) SendCode(w http.ResponseWriter, r *http.Request) {
	var req sendCodeRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, err)
		return
	}
	if req.Purpose == "" {
		req.Purpose = "register"
	}
	if err := c.svc.SendVerifyCode(r.Context(), req.Email, req.Purpose); err != nil {
		writeError(w, http.StatusBadRequest, err)
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"message": "验证码已发送"})
}

// registerRequest 注册请求。
type registerRequest struct {
	Username string `json:"username"`
	Email    string `json:"email"`
	Code     string `json:"code"`
	Password string `json:"password"`
}

// Register 处理 POST /api/auth/register，邮箱+验证码注册。
func (c *AuthController) Register(w http.ResponseWriter, r *http.Request) {
	var req registerRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, err)
		return
	}
	user, err := c.svc.Register(r.Context(), req.Username, req.Email, req.Code, req.Password)
	if err != nil {
		writeError(w, http.StatusBadRequest, err)
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"id":       user.ID,
		"username": user.Username,
		"email":    user.Email,
	})
}

// loginRequest 登录请求。
type loginRequest struct {
	Username string `json:"username"`
	Email    string `json:"email"`
	Code     string `json:"code"`
	Password string `json:"password"`
}

// Login 处理 POST /api/auth/login。
// 支持两种登录方式：
//   - 用户名+密码：{ username, password }
//   - 邮箱+验证码：{ email, code }
func (c *AuthController) Login(w http.ResponseWriter, r *http.Request) {
	var req loginRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, err)
		return
	}

	var user *model.User
	var token string
	var err error

	if req.Username != "" {
		// 用户名+密码登录
		user, token, err = c.svc.LoginByUsername(r.Context(), req.Username, req.Password)
	} else if req.Code != "" {
		// 邮箱+验证码登录
		user, token, err = c.svc.Login(r.Context(), req.Email, req.Code)
	} else {
		writeError(w, http.StatusBadRequest, fmt.Errorf("请输入用户名密码或邮箱验证码"))
		return
	}
	if err != nil {
		writeError(w, http.StatusUnauthorized, err)
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{
		"id":       user.ID,
		"username": user.Username,
		"email":    user.Email,
		"token":    token,
	})
}

// Me 处理 GET /api/auth/me，返回当前登录用户信息。
func (c *AuthController) Me(w http.ResponseWriter, r *http.Request) {
	token := extractToken(r)
	if token == "" {
		writeError(w, http.StatusUnauthorized, fmt.Errorf("未登录"))
		return
	}
	u, err := c.svc.ValidateToken(r.Context(), token)
	if err != nil {
		writeError(w, http.StatusUnauthorized, err)
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"id":       u.ID,
		"username": u.Username,
		"email":    u.Email,
	})
}

// Logout 处理 POST /api/auth/logout，注销当前会话。
func (c *AuthController) Logout(w http.ResponseWriter, r *http.Request) {
	token := extractToken(r)
	if token != "" {
		c.svc.Logout(token)
	}
	writeJSON(w, http.StatusOK, map[string]string{"message": "已退出"})
}

// extractToken 从 Cookie 或 Authorization 头中提取 token。
func extractToken(r *http.Request) string {
	if c, err := r.Cookie("auth_token"); err == nil && c.Value != "" {
		return c.Value
	}
	if h := r.Header.Get("Authorization"); h != "" {
		if strings.HasPrefix(h, "Bearer ") {
			return strings.TrimPrefix(h, "Bearer ")
		}
	}
	return ""
}