// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// 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 main

import (
	"encoding/json"
	"encoding/xml"
	"fmt"
	"math/rand"
	"net/http"
	"strings"
	"time"

	log "github.com/sirupsen/logrus"
)

const letterBytes = "abcdefghijklmnopqrstuvwxyz01234569"
const (
	letterIdxBits = 6                    // 6 bits to represent a letter index
	letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
	letterIdxMax  = 63 / letterIdxBits   // # of letter indices fitting in 63 bits
)

// different kinds of test failures
const (
	PASS = "PASS" // Indicate that a test passed
	FAIL = "FAIL" // Indicate that a test failed
)

type errorResponse struct {
	XMLName    xml.Name `xml:"Error" json:"-"`
	Code       string
	Message    string
	BucketName string
	Key        string
	RequestID  string `xml:"RequestId"`
	HostID     string `xml:"HostId"`

	// Region where the bucket is located. This header is returned
	// only in HEAD bucket and ListObjects response.
	Region string

	// Headers of the returned S3 XML error
	Headers http.Header `xml:"-" json:"-"`
}

type mintJSONFormatter struct {
}

func (f *mintJSONFormatter) Format(entry *log.Entry) ([]byte, error) {
	data := make(log.Fields, len(entry.Data))
	for k, v := range entry.Data {
		switch v := v.(type) {
		case error:
			// Otherwise errors are ignored by `encoding/json`
			// https://github.com/sirupsen/logrus/issues/137
			data[k] = v.Error()
		default:
			data[k] = v
		}
	}

	serialized, err := json.Marshal(data)
	if err != nil {
		return nil, fmt.Errorf("Failed to marshal fields to JSON, %w", err)
	}
	return append(serialized, '\n'), nil
}

// log successful test runs
func successLogger(function string, args map[string]interface{}, startTime time.Time) *log.Entry {
	// calculate the test case duration
	duration := time.Since(startTime)
	// log with the fields as per mint
	fields := log.Fields{"name": "versioning", "function": function, "args": args, "duration": duration.Nanoseconds() / 1000000, "status": PASS}
	return log.WithFields(fields)
}

// log not applicable test runs
func ignoreLog(function string, args map[string]interface{}, startTime time.Time, alert string) *log.Entry {
	// calculate the test case duration
	duration := time.Since(startTime)
	// log with the fields as per mint
	fields := log.Fields{"name": "versioning", "function": function, "args": args,
		"duration": duration.Nanoseconds() / 1000000, "status": "NA", "alert": strings.Split(alert, " ")[0] + " is NotImplemented"}
	return log.WithFields(fields)
}

// log failed test runs
func failureLog(function string, args map[string]interface{}, startTime time.Time, alert string, message string, err error) *log.Entry {
	// calculate the test case duration
	duration := time.Since(startTime)
	var fields log.Fields
	// log with the fields as per mint
	if err != nil {
		fields = log.Fields{"name": "versioning", "function": function, "args": args,
			"duration": duration.Nanoseconds() / 1000000, "status": FAIL, "alert": alert, "message": message, "error": err}
	} else {
		fields = log.Fields{"name": "versioning", "function": function, "args": args,
			"duration": duration.Nanoseconds() / 1000000, "status": FAIL, "alert": alert, "message": message}
	}
	return log.WithFields(fields)
}

func randString(n int, src rand.Source, prefix string) string {
	b := make([]byte, n)
	// A rand.Int63() generates 63 random bits, enough for letterIdxMax letters!
	for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
		if remain == 0 {
			cache, remain = src.Int63(), letterIdxMax
		}
		if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
			b[i] = letterBytes[idx]
			i--
		}
		cache >>= letterIdxBits
		remain--
	}
	return prefix + string(b[0:30-len(prefix)])
}