/*
   GoToSocial
   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU Affero General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Affero General Public License for more details.

   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package router

import (
	"fmt"
	"net/http"
	"time"

	"codeberg.org/gruf/go-bytesize"
	"codeberg.org/gruf/go-errors/v2"
	"codeberg.org/gruf/go-kv"
	"codeberg.org/gruf/go-logger/v2/level"
	"github.com/gin-gonic/gin"
	"github.com/superseriousbusiness/gotosocial/internal/log"
)

// loggingMiddleware provides a request logging and panic recovery gin handler.
func loggingMiddleware(c *gin.Context) {
	// Initialize the logging fields
	fields := make(kv.Fields, 6, 7)

	// Determine pre-handler time
	before := time.Now()

	defer func() {
		code := c.Writer.Status()
		path := c.Request.URL.Path

		if r := recover(); r != nil {
			if c.Writer.Status() == 0 {
				// No response was written, send a generic Internal Error
				c.Writer.WriteHeader(http.StatusInternalServerError)
			}

			// Append panic information to the request ctx
			err := fmt.Errorf("recovered panic: %v", r)
			_ = c.Error(err)

			// Dump a stacktrace to error log
			callers := errors.GetCallers(3, 10)
			log.WithField("stacktrace", callers).Error(err)
		}

		// NOTE:
		// It is very important here that we are ONLY logging
		// the request path, and none of the query parameters.
		// Query parameters can contain sensitive information
		// and could lead to storing plaintext API keys in logs

		// Set request logging fields
		fields[0] = kv.Field{"latency", time.Since(before)}
		fields[1] = kv.Field{"clientIP", c.ClientIP()}
		fields[2] = kv.Field{"userAgent", c.Request.UserAgent()}
		fields[3] = kv.Field{"method", c.Request.Method}
		fields[4] = kv.Field{"statusCode", code}
		fields[5] = kv.Field{"path", path}

		var lvl level.LEVEL

		// Default is info
		lvl = level.INFO

		if code >= 500 {
			// This is a server error
			lvl = level.ERROR

			if len(c.Errors) > 0 {
				// Add an error string log field
				fields = append(fields, kv.Field{
					"error", c.Errors.String(),
				})
			}
		}

		// Generate a nicer looking bytecount
		size := bytesize.Size(c.Writer.Size())

		// Create log entry with fields
		l := log.WithFields(fields...)

		// Finally, write log entry with status text body size
		l.Logf(lvl, "%s: wrote %s", http.StatusText(code), size)
	}()

	// Process request
	c.Next()
}