package batchfields

import (
	"regexp"
	"strings"
	"unicode/utf8"
)

const (
	ItemIDLimit            = 64
	DetailReasonLimit      = 512
	FailureReasonByteLimit = 4096
)

var mysqlErrorAfterSQL = regexp.MustCompile(`(?i): Error [0-9]{3,5} \([0-9A-Z]{5}\): [^\r\n]{0,160}`)

func DetailReason(value string) string {
	runes := []rune(strings.TrimSpace(value))
	if len(runes) > DetailReasonLimit {
		return string(runes[:DetailReasonLimit])
	}
	return string(runes)
}

func ItemID(value string) string {
	if utf8.RuneCountInString(value) > ItemIDLimit {
		return ""
	}
	return value
}

func FailureReason(value string) string {
	value = strings.ToValidUTF8(strings.TrimSpace(value), "")
	upper := strings.ToUpper(value)
	for _, marker := range []string{": INSERT INTO ", ": UPDATE ", ": SELECT ", ": DELETE FROM "} {
		if index := strings.Index(upper, marker); index >= 0 {
			databaseError := mysqlErrorAfterSQL.FindString(value[index+len(marker):])
			value = value[:index] + " (SQL omitted)" + databaseError
			break
		}
	}
	if len(value) <= FailureReasonByteLimit {
		return value
	}
	end := FailureReasonByteLimit - 3
	for end > 0 && !utf8.RuneStart(value[end]) {
		end--
	}
	return value[:end] + "..."
}