package collect

import (
	"encoding/json"
	"os/exec"
	"strings"
	"time"
)

// ShareServices is the read-only view of the file-sharing daemons.
type ShareServices struct {
	SMBInstalled bool `json:"smb_installed"`
	NFSInstalled bool `json:"nfs_installed"`
	SMBActive    bool `json:"smb_active"`
	NFSActive    bool `json:"nfs_active"`
	SMBSessions  int  `json:"smb_sessions"`
}

// ReadShareServices checks which sharing daemons exist and run.
func ReadShareServices() ShareServices {
	var s ShareServices
	if _, err := exec.LookPath("smbd"); err == nil {
		s.SMBInstalled = true
		s.SMBActive = unitActive("smbd")
		if s.SMBActive {
			s.SMBSessions = smbSessions()
		}
	}
	if _, err := exec.LookPath("exportfs"); err == nil {
		s.NFSInstalled = true
		s.NFSActive = unitActive("nfs-server")
	}
	return s
}

func unitActive(unit string) bool {
	out, _ := run(5*time.Second, "systemctl", "is-active", unit)
	return strings.TrimSpace(string(out)) == "active"
}

// smbSessions counts connected SMB sessions via smbstatus --json (Samba ≥ 4.17).
func smbSessions() int {
	out, err := run(10*time.Second, "smbstatus", "--json", "-b")
	if err != nil && len(out) == 0 {
		return 0
	}
	return parseSmbSessions(out)
}

func parseSmbSessions(b []byte) int {
	var j struct {
		Sessions map[string]json.RawMessage `json:"sessions"`
	}
	if json.Unmarshal(b, &j) != nil {
		return 0
	}
	return len(j.Sessions)
}