report.go

package main

import (
	"bytes"
	"fmt"
	"html/template"
)

type LogReporter struct {
	db       *LogDb
	resolver *DnsResolver
	tmpl     *template.Template
}

func NewLogReporter(db *LogDb) (*LogReporter, error) {
	resolver, err := NewDnsResolver(db)
	if err != nil {
		return nil, err
	}

	res := &LogReporter{db: db, resolver: resolver}
	err = res.loadTemplates()
	if err != nil {
		return nil, fmt.Errorf("error when loading templates: %s", err)
	}
	return res, nil
}

func (t *LogReporter) GenerateReport() (string, error) {
	lastId, err := t.db.GetLastId()
	if err != nil {
		return "", err
	}

	srcIpData, err := t.db.GetSrcIpReportData(lastId)
	if err != nil {
		return "", err
	}
	for i := 0; i < len(srcIpData); i++ {
		srcIpData[i].SrcHost, err = t.resolver.ResolveDomain(srcIpData[i].SrcIp)
		WarnIfErr(err)
	}

	userData, err := t.db.GetUsersReportData(lastId)
	if err != nil {
		return "", err
	}

	tplWriter := bytes.NewBufferString("")
	err = t.tmpl.ExecuteTemplate(tplWriter, "report.html.tmpl", map[string]any{
		"SrcIpData": srcIpData,
		"UserData":  userData,
	})
	if err != nil {
		return "", err
	}

	var newLastId uint64
	for _, data := range srcIpData {
		newLastId = max(newLastId, data.LastId)
	}
	for _, data := range userData {
		newLastId = max(newLastId, data.LastId)
	}

	if err = t.db.SetLastId(newLastId); err != nil {
		return "", err
	}

	return tplWriter.String(), nil
}

func (t *LogReporter) loadTemplates() error {
	tmpl, err := template.New("").Funcs(template.FuncMap{
		"attr": func(s string) template.HTMLAttr {
			return template.HTMLAttr(s)
		},
	}).ParseGlob("templates/*.tmpl")
	if err != nil {
		return err
	}
	t.tmpl = tmpl

	return nil
}