package handlers

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"time"

	"giteapm/internal/middleware"
	"giteapm/internal/models"

	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
	"golang.org/x/oauth2"
)

type GiteaUser struct {
	ID        int    `json:"id"`
	Login     string `json:"login"`
	FullName  string `json:"full_name"`
	Email     string `json:"email"`
	AvatarURL string `json:"avatar_url"`
}

func (h *Handlers) GiteaLogin(c *gin.Context) {
	config := &oauth2.Config{
		ClientID:     h.Cfg.Gitea.ClientID,
		ClientSecret: h.Cfg.Gitea.ClientSecret,
		RedirectURL:  h.Cfg.Gitea.RedirectURL,
		Scopes:       []string{"read:user"},
		Endpoint: oauth2.Endpoint{
			AuthURL:  h.Cfg.Gitea.BaseURL + "/login/oauth/authorize",
			TokenURL: h.Cfg.Gitea.BaseURL + "/login/oauth/access_token",
		},
	}

	state := "random-state-string"
	url := config.AuthCodeURL(state, oauth2.AccessTypeOffline)
	
	c.JSON(http.StatusOK, SuccessResponse(gin.H{
		"auth_url": url,
	}))
}

func (h *Handlers) GiteaCallback(c *gin.Context) {
	// 记录所有查询参数用于调试
	fmt.Printf("OAuth回调收到的所有参数: %v\n", c.Request.URL.Query())
	
	code := c.Query("code")
	state := c.Query("state")
	errorParam := c.Query("error")
	
	fmt.Printf("OAuth回调 - code: %s, state: %s, error: %s\n", code, state, errorParam)
	
	if errorParam != "" {
		c.JSON(http.StatusBadRequest, ErrorResponse(400, fmt.Sprintf("OAuth授权失败: %s", errorParam)))
		return
	}
	
	if code == "" {
		c.JSON(http.StatusBadRequest, ErrorResponse(400, "缺少授权码"))
		return
	}

	config := &oauth2.Config{
		ClientID:     h.Cfg.Gitea.ClientID,
		ClientSecret: h.Cfg.Gitea.ClientSecret,
		RedirectURL:  h.Cfg.Gitea.RedirectURL,
		Scopes:       []string{"read:user"},
		Endpoint: oauth2.Endpoint{
			AuthURL:  h.Cfg.Gitea.BaseURL + "/login/oauth/authorize",
			TokenURL: h.Cfg.Gitea.BaseURL + "/login/oauth/access_token",
		},
	}

	token, err := config.Exchange(c.Request.Context(), code)
	if err != nil {
		c.JSON(http.StatusBadRequest, ErrorResponse(400, "授权码交换失败"))
		return
	}

	client := config.Client(c.Request.Context(), token)
	resp, err := client.Get(h.Cfg.Gitea.BaseURL + "/api/v1/user")
	if err != nil {
		c.JSON(http.StatusInternalServerError, ErrorResponse(500, "获取用户信息失败"))
		return
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		c.JSON(http.StatusInternalServerError, ErrorResponse(500, "读取用户信息失败"))
		return
	}

	var giteaUser GiteaUser
	if err := json.Unmarshal(body, &giteaUser); err != nil {
		c.JSON(http.StatusInternalServerError, ErrorResponse(500, "解析用户信息失败"))
		return
	}

	user, err := models.GetUserByGiteaID(uint(giteaUser.ID))
	if err != nil {
		user = &models.User{
			GiteaUserID: func() *uint { id := uint(giteaUser.ID); return &id }(),
			Username:    giteaUser.Login,
			Email:       giteaUser.Email,
			FullName:    giteaUser.FullName,
			AvatarURL:   giteaUser.AvatarURL,
			Role:        "developer",
		}
		if err := models.CreateUser(user); err != nil {
			c.JSON(http.StatusInternalServerError, ErrorResponse(500, "创建用户失败"))
			return
		}
	} else {
		user.Username = giteaUser.Login
		user.Email = giteaUser.Email
		user.FullName = giteaUser.FullName
		user.AvatarURL = giteaUser.AvatarURL
		if err := models.UpdateUser(user); err != nil {
			c.JSON(http.StatusInternalServerError, ErrorResponse(500, "更新用户失败"))
			return
		}
	}

	jwtToken, err := h.generateJWT(user)
	if err != nil {
		c.JSON(http.StatusInternalServerError, ErrorResponse(500, "生成JWT失败"))
		return
	}

	// 重定向到前端页面，并通过URL参数传递token
	redirectURL := fmt.Sprintf("/?token=%s", jwtToken)
	c.Redirect(http.StatusFound, redirectURL)
}

func (h *Handlers) Logout(c *gin.Context) {
	c.JSON(http.StatusOK, SuccessResponse(gin.H{
		"message": "登出成功",
	}))
}

func (h *Handlers) generateJWT(user *models.User) (string, error) {
	claims := &middleware.Claims{
		UserID:   user.ID,
		Username: user.Username,
		Role:     user.Role,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Duration(h.Cfg.JWT.ExpireHour) * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			Subject:   fmt.Sprintf("%d", user.ID),
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString([]byte(h.Cfg.JWT.Secret))
}