package tcp

import (
	"fmt"
	"net/url"
	"strconv"
	"strings"

	"github.com/elastic/beats/libbeat/common"
	"github.com/elastic/beats/libbeat/logp"
	"github.com/elastic/beats/libbeat/outputs"

	"github.com/elastic/beats/heartbeat/monitors"
)

func init() {
	monitors.RegisterActive("tcp", create)
}

var debugf = logp.MakeDebug("tcp")

type connURL struct {
	Scheme string
	Host   string
	Ports  []uint16
}

func create(
	info monitors.Info,
	cfg *common.Config,
) ([]monitors.Job, error) {
	config := DefaultConfig
	if err := cfg.Unpack(&config); err != nil {
		return nil, err
	}

	tls, err := outputs.LoadTLSConfig(config.TLS)
	if err != nil {
		return nil, err
	}

	defaultScheme := "tcp"
	if tls != nil {
		defaultScheme = "ssl"
	}
	addrs, err := collectHosts(&config, defaultScheme)
	if err != nil {
		return nil, err
	}

	if config.Socks5.URL != "" && !config.Socks5.LocalResolve {
		var jobs []monitors.Job
		for _, addr := range addrs {
			scheme, host := addr.Scheme, addr.Host
			for _, port := range addr.Ports {
				job, err := newTCPMonitorHostJob(scheme, host, port, tls, &config)
				if err != nil {
					return nil, err
				}
				jobs = append(jobs, job)
			}
		}
		return jobs, nil
	}

	jobs := make([]monitors.Job, len(addrs))
	for i, addr := range addrs {
		jobs[i], err = newTCPMonitorIPsJob(addr, tls, &config)
		if err != nil {
			return nil, err
		}
	}
	return jobs, nil
}

func collectHosts(config *Config, defaultScheme string) ([]connURL, error) {
	var addrs []connURL
	for _, h := range config.Hosts {
		scheme := defaultScheme
		host := ""
		u, err := url.Parse(h)

		if err != nil || u.Host == "" {
			host = h
		} else {
			scheme = u.Scheme
			host = u.Host
		}
		debugf("Add tcp endpoint '%v://%v'.", scheme, host)

		switch scheme {
		case "tcp", "plain", "tls", "ssl":
		default:
			err := fmt.Errorf("'%v' is no supported connection scheme in '%v'", scheme, h)
			return nil, err
		}

		pair := strings.SplitN(host, ":", 2)
		ports := config.Ports
		if len(pair) == 2 {
			port, err := strconv.ParseUint(pair[1], 10, 16)
			if err != nil {
				return nil, fmt.Errorf("'%v' is no valid port number in '%v'", pair[1], h)
			}

			ports = []uint16{uint16(port)}
			host = pair[0]
		} else if len(config.Ports) == 0 {
			return nil, fmt.Errorf("host '%v' missing port number", h)
		}

		addrs = append(addrs, connURL{
			Scheme: scheme,
			Host:   host,
			Ports:  ports,
		})
	}
	return addrs, nil
}