package api

import (
	"bufio"
	"context"
	"net/http"
	"os/exec"
	"time"

	ffprobe "github.com/datarhei/core/v16/ffmpeg/probe"
	"github.com/datarhei/core/v16/log"

	"github.com/labstack/echo/v4"
)

// NDIHandler provides an endpoint to discover NDI sources via ffmpeg
type NDIHandler struct {
	logger log.Logger
}

// NewNDI returns a new NDIHandler
func NewNDI() *NDIHandler {
	return &NDIHandler{
		logger: log.New("NDI"),
	}
}

// SourcesResponse represents a discovered source
type SourcesResponse struct {
	Address string `json:"address"`
	Format  string `json:"format"`
}

// Sources runs ffmpeg to find NDI sources and returns parsed inputs
func (h *NDIHandler) Sources(c echo.Context) error {
	ctx, cancel := context.WithTimeout(context.Background(), 4*time.Second)
	defer cancel()

	// ffmpeg prints diagnostics on stderr
	cmd := exec.CommandContext(ctx, "ffmpeg", "-hide_banner", "-nostdin", "-loglevel", "info", "-f", "libndi_newtek", "-find_sources", "1", "-i", "dummy", "-t", "0.5", "-f", "null", "-")

	sd, err := cmd.StderrPipe()
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	p := ffprobe.New(ffprobe.Config{Logger: h.logger})

	if err := cmd.Start(); err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
	}

	scanner := bufio.NewScanner(sd)
	for scanner.Scan() {
		line := scanner.Text()
		p.Parse(line)
	}

	_ = cmd.Wait()

	// Parse collected data
	p.ResetStats()
	probe := p.Probe()

	out := make([]SourcesResponse, 0, len(probe.Streams))
	for _, s := range probe.Streams {
		out = append(out, SourcesResponse{
			Address: s.Address,
			Format:  s.Format,
		})
	}

	return c.JSON(http.StatusOK, out)
}