package contact

import (
	"bytes"
	"errors"
	"io"
	"net/http"
	"strings"

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

const maxChannelRequestBytes = 8 * 1024
const channelBodyKey = "bell.contact.channel-body"
const channelBodyErrorKey = "bell.contact.channel-body-error"

var redactedChannelBody = []byte(`{"redacted":true}`)

// RedactRequestBody must run before GoAdmin's LoggerToFile middleware. The
// handler restores the original body from Gin context, while sys_opera_log
// only sees a fixed marker and never the contact address.
func RedactRequestBody() gin.HandlerFunc {
	return func(c *gin.Context) {
		if c.Request.Method != http.MethodPost || !isChannelCreatePath(c.Request.URL.Path) {
			c.Next()
			return
		}
		body, err := io.ReadAll(io.LimitReader(c.Request.Body, maxChannelRequestBytes+1))
		if err != nil {
			c.Set(channelBodyErrorKey, err)
		} else if len(body) > maxChannelRequestBytes {
			c.Set(channelBodyErrorKey, errors.New("request body too large"))
		} else {
			c.Set(channelBodyKey, body)
		}
		_ = c.Request.Body.Close()
		c.Request.Body = io.NopCloser(bytes.NewReader(redactedChannelBody))
		c.Next()
	}
}

func restoreChannelBody(c *gin.Context) error {
	if value, ok := c.Get(channelBodyErrorKey); ok {
		return value.(error)
	}
	value, ok := c.Get(channelBodyKey)
	if !ok {
		return errors.New("channel request body was not captured")
	}
	c.Request.Body = io.NopCloser(bytes.NewReader(value.([]byte)))
	return nil
}

func isChannelCreatePath(path string) bool {
	const prefix = "/api/v1/bell/contacts/"
	const suffix = "/channels"
	if !strings.HasPrefix(path, prefix) || !strings.HasSuffix(path, suffix) {
		return false
	}
	id := strings.TrimSuffix(strings.TrimPrefix(path, prefix), suffix)
	return id != "" && !strings.Contains(id, "/")
}