//go:build !windows

package deploy

import (
	"os"
	"os/exec"
	"strconv"
	"strings"
)

var serviceDiscoverUnits = []string{
	"docker", "docker.service", "ssh", "sshd", "jenkins", "gitlab-runner",
	"cloudflared", "fail2ban", "ufw", "firewalld",
}

func probeLocalServices() []ServiceGraphEntry {
	var entries []ServiceGraphEntry
	for _, unit := range serviceDiscoverUnits {
		status := "not_found"
		if activeOut, err := exec.Command("systemctl", "is-active", unit).CombinedOutput(); err == nil {
			active := strings.TrimSpace(string(activeOut))
			switch active {
			case "active":
				status = "running"
			case "inactive", "failed", "dead":
				status = "stopped"
			default:
				if active != "unknown" {
					status = "stopped"
				}
			}
		}
		if status == "not_found" {
			continue
		}
		entries = append(entries, entryWithLane(unit, 0, "local_service"))
	}

	if _, err := os.Stat("/var/run/docker.sock"); err == nil {
		entries = append(entries, entryWithLane("docker", 0, "passive_hint"))
	}

	if out, err := exec.Command("ss", "-lnt").CombinedOutput(); err == nil {
		entries = append(entries, parseSSListening(string(out))...)
	} else if out, err := exec.Command("netstat", "-lnt").CombinedOutput(); err == nil {
		entries = append(entries, parseNetstatListening(string(out))...)
	}

	return dedupeEntries(entries)
}

func collectPassiveHints() []string {
	var hints []string
	if _, err := os.Stat("/var/run/docker.sock"); err == nil {
		hints = append(hints, "docker_socket")
	}
	for _, path := range []string{
		"/var/lib/gitlab-runner",
		"/etc/gitlab-runner",
		"/var/lib/jenkins",
	} {
		if _, err := os.Stat(path); err == nil {
			hints = append(hints, "runner_path:"+path)
		}
	}
	return hints
}

func parseSSListening(text string) []ServiceGraphEntry {
	var entries []ServiceGraphEntry
	for _, line := range strings.Split(text, "\n") {
		fields := strings.Fields(line)
		if len(fields) < 4 {
			continue
		}
		local := fields[3]
		port := parseListenPort(local)
		if port == 0 {
			continue
		}
		name := portServiceNames[port]
		if name == "" {
			name = "tcp/" + strconv.Itoa(port)
		}
		entries = append(entries, entryWithLane(name, port, "passive_hint"))
	}
	return entries
}

func parseNetstatListening(text string) []ServiceGraphEntry {
	var entries []ServiceGraphEntry
	for _, line := range strings.Split(text, "\n") {
		if !strings.Contains(line, "LISTEN") {
			continue
		}
		fields := strings.Fields(line)
		if len(fields) < 4 {
			continue
		}
		local := fields[3]
		port := parseListenPort(local)
		if port == 0 {
			continue
		}
		name := portServiceNames[port]
		if name == "" {
			name = "tcp/" + strconv.Itoa(port)
		}
		entries = append(entries, entryWithLane(name, port, "passive_hint"))
	}
	return entries
}

func parseListenPort(local string) int {
	// formats: *:22, 0.0.0.0:445, [::]:8080
	if i := strings.LastIndex(local, ":"); i >= 0 {
		portStr := strings.TrimSuffix(local[i+1:], "]")
		if n, err := strconv.Atoi(portStr); err == nil {
			return n
		}
	}
	return 0
}