package main

import (
	"encoding/xml"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"syscall"
)

const serviceLabel = "run.fc.byre"

const plistTemplate = `<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>Label</key>
	<string>%s</string>
	<key>ProgramArguments</key>
	<array>
		<string>%s</string>
		<string>serve</string>
	</array>
	<key>EnvironmentVariables</key>
	<dict>
		<key>PATH</key>
		<string>%s</string>
	</dict>
	<key>RunAtLoad</key>
	<true/>
	<key>KeepAlive</key>
	<true/>
	<key>StandardOutPath</key>
	<string>%s</string>
	<key>StandardErrorPath</key>
	<string>%s</string>
</dict>
</plist>
`

func installCmd() {
	requireChecks()
	exe, err := os.Executable()
	if err != nil {
		fatal("find executable", "err", err)
	}
	exe, err = filepath.EvalSymlinks(exe)
	if err != nil {
		fatal("resolve executable", "err", err)
	}
	home, err := os.UserHomeDir()
	if err != nil {
		fatal("home dir", "err", err)
	}

	plistPath := filepath.Join(home, "Library", "LaunchAgents", serviceLabel+".plist")
	logPath := filepath.Join(home, "Library", "Logs", "byre.log")
	plist := fmt.Sprintf(plistTemplate, xmlText(serviceLabel), xmlText(exe), xmlText(filepath.Dir(exe)+":"+os.Getenv("PATH")), xmlText(logPath), xmlText(logPath))
	err = os.MkdirAll(filepath.Dir(plistPath), 0o755)
	if err != nil {
		fatal("create launch agents dir", "err", err)
	}
	err = os.WriteFile(plistPath, []byte(plist), 0o644)
	if err != nil {
		fatal("write launch agent", "err", err)
	}
	fmt.Println("wrote", plistPath)

	fmt.Println("byre's loopback address is", loopbackURL)

	domain := fmt.Sprintf("gui/%d", os.Getuid())
	service := domain + "/" + serviceLabel
	if exec.Command("launchctl", "print", service).Run() != nil {
		run("launchctl", "bootstrap", domain, plistPath)
		fmt.Println("started", service, "running", exe)
		return
	}
	// bootout kills every process the service started, which includes this one when an agent runs it.
	reload := exec.Command("/bin/sh", "-c", `launchctl bootout "$1"; launchctl bootstrap "$2" "$3"`, "sh", service, domain, plistPath)
	reload.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
	err = reload.Start()
	if err != nil {
		fatal("restart service", "err", err)
	}
	fmt.Println("restarting", service, "on", exe)
}

func run(name string, args ...string) {
	cmd := exec.Command(name, args...)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	err := cmd.Run()
	if err != nil {
		fatal("run "+name, "args", args, "err", err)
	}
}

func xmlText(s string) string {
	var b strings.Builder
	xml.EscapeText(&b, []byte(s))
	return b.String()
}