package ffmpeg

import (
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
)

// BinPaths holds paths to ffmpeg and ffprobe binaries.
type BinPaths struct {
	FFmpeg  string
	FFprobe string
}

// Detect finds ffmpeg and ffprobe binaries.
// Priority: 1. build/bin/ (bundled)  2. PATH
func Detect() (BinPaths, error) {
	exeDir, err := os.Executable()
	if err != nil {
		exeDir = "."
	} else {
		exeDir = filepath.Dir(exeDir)
	}

	bundled := BinPaths{
		FFmpeg:  binPath(exeDir, "ffmpeg"),
		FFprobe: binPath(exeDir, "ffprobe"),
	}

	// Check bundled first
	if fileExists(bundled.FFmpeg) && fileExists(bundled.FFprobe) {
		return bundled, nil
	}

	// Fall back to PATH
	return findOnPath()
}

func binPath(baseDir, name string) string {
	ext := ""
	if runtime.GOOS == "windows" {
		ext = ".exe"
	}
	return filepath.Join(baseDir, "build", "bin", name+ext)
}

func fileExists(path string) bool {
	_, err := os.Stat(path)
	return err == nil
}

func findOnPath() (BinPaths, error) {
	ffmpeg, err := exec.LookPath("ffmpeg")
	if err != nil {
		return BinPaths{}, err
	}
	ffprobe, err := exec.LookPath("ffprobe")
	if err != nil {
		return BinPaths{}, err
	}
	return BinPaths{FFmpeg: ffmpeg, FFprobe: ffprobe}, nil
}