package mildware

import (
	"crypto/rand"
	"fmt"
	"log/slog"
	"net/http"
	"runtime/debug"
	"time"

	"gen2d/internal/logger"

	"github.com/gin-gonic/gin"
)

// Logger 返回 HTTP 请求日志中间件。
// 为每个请求生成 request_id，记录 method、path、status、latency、client_ip。
func Logger() gin.HandlerFunc {
	return func(c *gin.Context) {
		start := time.Now()
		requestID := generateRequestID()

		c.Set("request_id", requestID)
		ctx, _ := logger.WithRequestID(c.Request.Context(), requestID)
		c.Request = c.Request.WithContext(ctx)

		c.Header("X-Request-ID", requestID)

		c.Next()

		latency := time.Since(start)
		status := c.Writer.Status()

		l := logger.FromCtx(ctx)
		attrs := []slog.Attr{
			slog.String("method", c.Request.Method),
			slog.String("path", c.Request.URL.Path),
			slog.Int("status", status),
			slog.Duration("latency", latency),
			slog.String("client_ip", c.ClientIP()),
		}

		if status >= 500 {
			l.LogAttrs(ctx, slog.LevelError, "request completed", attrs...)
		} else if status >= 400 {
			l.LogAttrs(ctx, slog.LevelWarn, "request completed", attrs...)
		} else {
			l.LogAttrs(ctx, slog.LevelInfo, "request completed", attrs...)
		}
	}
}

// Recovery 返回自定义 panic 恢复中间件。
// panic 时记录完整的 request 上下文和堆栈，返回 500。
func Recovery() gin.HandlerFunc {
	return func(c *gin.Context) {
		defer func() {
			if r := recover(); r != nil {
				ctx := c.Request.Context()
				l := logger.FromCtx(ctx)
				l.Error("panic recovered",
					"error", fmt.Sprintf("%v", r),
					"method", c.Request.Method,
					"path", c.Request.URL.Path,
					"request_id", c.GetString("request_id"),
					"stack", string(debug.Stack()),
				)

				c.AbortWithStatusJSON(http.StatusInternalServerError,
					gin.H{"code": http.StatusInternalServerError, "message": "服务器内部错误"})
			}
		}()
		c.Next()
	}
}

func generateRequestID() string {
	b := make([]byte, 8)
	_, _ = rand.Read(b)
	return fmt.Sprintf("%d-%x", time.Now().UnixMilli(), b)
}