package middleware

import (
	"bytes"
	"io"
	"log/slog"
	"strings"
	"time"

	"kra/internal/conf"

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

// AccessLog is the single global request/response capture point, matching
// the reference middleware ordering and making every HTTP request observable.
func AccessLog(runtime *conf.Runtime, logger *slog.Logger) gin.HandlerFunc {
	return func(c *gin.Context) {
		var requestBody []byte
		multipart := strings.Contains(c.GetHeader("Content-Type"), "multipart/form-data")
		if c.Request.Body != nil && !multipart {
			requestBody, _ = io.ReadAll(c.Request.Body)
			c.Request.Body = io.NopCloser(bytes.NewReader(requestBody))
		}
		maxBytes := 1 << 20
		writer := &captureWriter{ResponseWriter: c.Writer, maxBytes: maxBytes}
		c.Writer = writer
		started := time.Now()
		c.Next()
		if logger == nil {
			return
		}
		requestText, responseText := "", ""
		config := runtime.Admin()
		logLimit := 32768
		if config != nil && config.Zap != nil && config.Zap.AccessLogMaxBytes > 0 {
			logLimit = int(config.Zap.AccessLogMaxBytes)
		}
		if config == nil || config.Zap == nil || config.Zap.AccessReqBody {
			if multipart {
				requestText = "[文件]"
			} else {
				requestText = redactJSONLimit(requestBody, logLimit)
			}
		}
		if config == nil || config.Zap == nil || config.Zap.AccessRespData {
			responseText = redactJSONLimit(writer.body.Bytes(), logLimit)
		}
		userID, authorityID := uint(0), uint(0)
		if claims := Claims(c); claims != nil {
			userID, authorityID = claims.ID, claims.AuthorityID
		}
		route := c.FullPath()
		if route == "" {
			route = "unmatched"
		}
		attributes := []any{
			"ip", c.ClientIP(), "method", c.Request.Method, "path", c.Request.URL.Path, "http_route", route,
			"status", c.Writer.Status(), "latency_ms", time.Since(started).Milliseconds(),
			"request_id", stringValueFromContext(c, "request_id"), "trace_id", stringValueFromContext(c, "trace_id"),
			"bytes_in", len(requestBody), "bytes_out", c.Writer.Size(), "user_id", userID, "authority_id", authorityID,
			"ua", c.Request.UserAgent(), "query", c.Request.URL.RawQuery, "request", requestText, "response", responseText}
		if config != nil && config.Zap != nil && config.Zap.AccessReqHeaders {
			attributes = append(attributes, "headers", redactHeaders(c.Request.Header))
		}
		logger.InfoContext(c.Request.Context(), "http access", attributes...)
	}
}

func redactHeaders(headers map[string][]string) map[string][]string {
	out := make(map[string][]string, len(headers))
	for key, values := range headers {
		lower := strings.ToLower(key)
		if strings.Contains(lower, "token") || lower == "authorization" || lower == "cookie" {
			out[key] = []string{"******"}
		} else {
			out[key] = values
		}
	}
	return out
}

func stringValueFromContext(c *gin.Context, key string) string {
	value, _ := c.Get(key)
	return stringValue(value)
}