// Package moonlight handles launching the Moonlight client.
// It locates the Moonlight executable and launches a stream session
// to a specific host and app.
package moonlight

import (
	"fmt"
	"os/exec"
	"runtime"
)

// DefaultPaths are the well-known install locations per platform.
var DefaultPaths = map[string][]string{
	"windows": {
		`C:\Program Files\Moonlight Game Streaming\Moonlight.exe`,
		`C:\Program Files (x86)\Moonlight Game Streaming\Moonlight.exe`,
	},
	"darwin": {
		"/Applications/Moonlight.app/Contents/MacOS/Moonlight",
	},
	"linux": {
		"/usr/bin/moonlight",
		"/usr/local/bin/moonlight",
	},
}

// Launcher knows how to start Moonlight.
type Launcher struct {
	execPath string
}

// New creates a Launcher, auto-detecting the Moonlight binary.
// Pass an empty string to use auto-detection.
func New(overridePath string) (*Launcher, error) {
	if overridePath != "" {
		if path, err := exec.LookPath(overridePath); err == nil {
			return &Launcher{execPath: path}, nil
		}
		return nil, fmt.Errorf("moonlight not found at %q", overridePath)
	}

	// Try PATH first
	if path, err := exec.LookPath("moonlight"); err == nil {
		return &Launcher{execPath: path}, nil
	}

	// Try well-known locations
	for _, candidate := range DefaultPaths[runtime.GOOS] {
		if path, err := exec.LookPath(candidate); err == nil {
			return &Launcher{execPath: path}, nil
		}
	}

	// Return a launcher even if not found — we'll surface the error at connect time
	return &Launcher{}, nil
}

// ExecPath returns the resolved path to the Moonlight binary.
func (l *Launcher) ExecPath() string {
	return l.execPath
}

// Stream launches a Moonlight stream to the given host + app.
// app is typically "Desktop" for a full desktop stream.
func (l *Launcher) Stream(hostIP, app string) error {
	if l.execPath == "" {
		return fmt.Errorf("Moonlight executable not found — please install Moonlight or set MOONLIGHT_PATH")
	}
	// moonlight stream <host> <app>
	cmd := exec.Command(l.execPath, "stream", hostIP, app)
	cmd.Stdout = nil
	cmd.Stderr = nil
	return cmd.Start() // non-blocking — let Moonlight own its window
}

// Pair runs the Moonlight pairing flow for a host.
func (l *Launcher) Pair(hostIP string) error {
	if l.execPath == "" {
		return fmt.Errorf("Moonlight executable not found")
	}
	cmd := exec.Command(l.execPath, "pair", hostIP)
	cmd.Stdout = nil
	cmd.Stderr = nil
	return cmd.Start()
}