package main

import (
	"embed"
	"fmt"
	"os"
	"strconv"
	"strings"

	"github.com/wailsapp/wails/v2"
	"github.com/wailsapp/wails/v2/pkg/options"
	"github.com/wailsapp/wails/v2/pkg/options/assetserver"
)

//go:embed all:frontend/dist
var assets embed.FS

func main() {
	noGUI, port, help := parseSysmonArgs()

	if help {
		printHelp()
		os.Exit(0)
	}

	if noGUI {
		runServer(port)
		return
	}

	// Create an instance of the app structure
	app := NewApp()

	// Create application with options
	err := wails.Run(&options.App{
		Title:  "sysmon",
		Width:  1024,
		Height: 768,
		AssetServer: &assetserver.Options{
			Assets: assets,
		},
		BackgroundColour: &options.RGBA{R: 27, G: 38, B: 54, A: 1},
		OnStartup:        app.startup,
		Bind: []interface{}{
			app,
		},
	})

	if err != nil {
		println("Error:", err.Error())
	}
}

// parseSysmonArgs scans os.Args manually so we don't call flag.Parse(),
// which would conflict with flags that Wails injects in dev mode (e.g. -assetdir).
func parseSysmonArgs() (noGUI bool, port int, help bool) {
	port = 9731
	args := os.Args[1:]
	for i := 0; i < len(args); i++ {
		arg := args[i]
		switch arg {
		case "--no-gui":
			noGUI = true
		case "--help", "-h":
			help = true
		case "--port":
			if i+1 < len(args) {
				i++
				if p, err := strconv.Atoi(args[i]); err == nil && p > 0 && p <= 65535 {
					port = p
				}
			}
		default:
			if strings.HasPrefix(arg, "--port=") {
				if p, err := strconv.Atoi(strings.TrimPrefix(arg, "--port=")); err == nil && p > 0 && p <= 65535 {
					port = p
				}
			}
		}
	}
	return
}

func printHelp() {
	fmt.Print(`sysmon — system monitor

Usage:
  sysmon                       Launch with graphical interface (default)
  sysmon --no-gui              Run as headless HTTP API server (port 9731)
  sysmon --no-gui --port N     Run server on port N

Options:
  --no-gui          Start without GUI, expose HTTP API instead
  --port <number>   HTTP server port (default: 9731, requires --no-gui)
  --help, -h        Show this help

Server endpoints (--no-gui mode):
  GET  /api/metrics              Latest metrics snapshot (JSON)
  GET  /api/metrics/stream       Server-Sent Events stream (1 s interval)
  GET  /api/process/<pid>        Process detail (JSON)
  POST /api/process/<pid>/kill   Kill process  (?force=true → SIGKILL)
  GET  /api/man/<name>           Manual page for a command
`)
}