package middleware

import (
	"context"
	"errors"
	"log/slog"
	"strings"

	"git.lzcwy.cn/zhengchiliu/zt-online-game-backend/pkg/app"
	"git.lzcwy.cn/zhengchiliu/zt-online-game-backend/pkg/errcode"
	"git.lzcwy.cn/zhengchiliu/zt-online-game-backend/pkg/lzcwyjwt"
	"github.com/gin-gonic/gin"
)

type ctxKey string

const (
	userIDKey ctxKey = "userID"
)

func JWTAuth() gin.HandlerFunc {
	return func(c *gin.Context) {
		response := app.NewResponse(c)

		// 1. 从 Authorization 头取 token：Bearer xxx.yyy.zzz
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			slog.WarnContext(c.Request.Context(), "jwt auth: authorization header missing",
				"method", c.Request.Method, "path", c.Request.URL.Path, "ip", c.ClientIP())
			response.ToErrorResponse(errcode.UnauthorizedTokenMissing)
			c.Abort()
			return
		}

		parts := strings.SplitN(authHeader, " ", 2)
		if len(parts) != 2 || parts[0] != "Bearer" {
			slog.WarnContext(c.Request.Context(), "jwt auth: invalid authorization format",
				"method", c.Request.Method, "path", c.Request.URL.Path, "ip", c.ClientIP())
			response.ToErrorResponse(errcode.UnauthorizedTokenError.WithDetails("invalid Authorization format"))
			c.Abort()
			return
		}

		// 2. 解析 token
		claims, err := lzcwyjwt.ParseAccessToken(parts[1])
		if err != nil {
			switch {
			case errors.Is(err, lzcwyjwt.ErrTokenExpired):
				slog.InfoContext(c.Request.Context(), "jwt auth: token expired", "path", c.Request.URL.Path)
				response.ToErrorResponse(errcode.UnauthorizedTokenTimeout)
			case errors.Is(err, lzcwyjwt.ErrTokenWrongType):
				slog.WarnContext(c.Request.Context(), "jwt auth: token type mismatch", "path", c.Request.URL.Path)
				response.ToErrorResponse(errcode.UnauthorizedTokenError.WithDetails("token type mismatch"))
			default:
				slog.WarnContext(c.Request.Context(), "jwt auth: parse token failed",
					"path", c.Request.URL.Path, "ip", c.ClientIP(), "error", err)
				response.ToErrorResponse(errcode.UnauthorizedTokenError.WithDetails(err.Error()))
			}
			c.Abort()
			return
		}

		// 4. 把 userID注入 context
		ctx := context.WithValue(c.Request.Context(), userIDKey, claims.UserID)
		c.Request = c.Request.WithContext(ctx)

		c.Next()
	}
}

// GetUserID 从 context 取登录用户 ID（在 handler 里用）
func GetUserID(ctx context.Context) (int64, bool) {
	uid, ok := ctx.Value(userIDKey).(int64)
	return uid, ok
}