package main

import (
    "github.com/haproxytech/config-parser/v2"
    // ...
)
// ...

func main() {
    p := parser.Parser{}
    err := p.LoadData("/path/to/haproxy/file.cfg")
    log.Println(err)
    log.Println(p.String())

    {
        data, _ := p.Get(parser.Comments, parser.CommentsSectionName, "# _version", true)
        if err == errors.ErrFetch {
            log.Panicln("we have an fetch error !!")
        }
        ver, _ := data.(*types.Int64C)
        ver.Value = ver.Value + 1
    }

    {
        p.Set(parser.Frontends, "http", "option forwardfor", types.OptionForwardFor{})
    }

    {
        data, err := p.Get(parser.Global, parser.GlobalSectionName, "stats socket")
        if err != nil {
            log.Panicln(err)
        }
        val, _ := data.([]types.Socket)
        log.Println(val[0])
        val[0].Path = "$PWD/haproxy-runtime-api.1.sock"
        log.Println(val[0])
    }

    {
        data, err := p.Get(parser.Global, parser.GlobalSectionName, "daemon")
        log.Println(data, err)
        if err == errors.ErrFetch {
            log.Panicln("we have an fetch error !!")
        }
        //remove it
        p.Set(parser.Global, parser.GlobalSectionName, "daemon", nil)
    }

    {
        datar, err := p.Get(parser.Resolvers, "ns1", "nameserver")
        if err == nil {
            ns := datar.([]types.Nameserver)
            log.Println(ns[0].Name, ns[0].Address)
            log.Println(ns[1].Name, ns[1].Address)
            ns[1].Name = "hahaha"
            ns[0].Address = "0.0.0.0:8080"
        }
        datar, err = p.Get(parser.Resolvers, "ns1", "nameserver")
        if err == nil {
            ns := datar.([]types.Nameserver)
            log.Println(ns[0].Name, ns[0].Address)
            log.Println(ns[1].Name, ns[1].Address)
        }
    }

    {
        log.Println("nbproc ==================================================")
        data, err := p.Get(parser.Global, parser.GlobalSectionName, "nbproc")
        if err != nil {
            log.Println(err)
        } else {
            d := data.(*types.Int64C)
            log.Println(d.Value)
            d.Value = 5
        }
    }

    p.Save(configFilename)
}