package probe

import (
	"encoding/json"
	"fmt"
	"os/exec"
	"strconv"
)

type ProbeResult struct {
	Duration   float64      `json:"duration"`
	Width      int          `json:"width"`
	Height     int          `json:"height"`
	VideoCodec string       `json:"video_codec"`
	Bitrate    int64        `json:"bitrate"`
	Audio      []AudioTrack `json:"audio_tracks"`
	Subtitles  []SubTrack   `json:"subtitle_tracks"`
}

type AudioTrack struct {
	Index    int    `json:"index"`
	Codec    string `json:"codec"`
	Language string `json:"language"`
	Channels int    `json:"channels"`
}

type SubTrack struct {
	Index    int    `json:"index"`
	Codec    string `json:"codec"`
	Language string `json:"language"`
	URL      string `json:"url,omitempty"`
}

type ffprobeOutput struct {
	Format  ffprobeFormat   `json:"format"`
	Streams []ffprobeStream `json:"streams"`
}

type ffprobeFormat struct {
	Duration string `json:"duration"`
	BitRate  string `json:"bit_rate"`
}

type ffprobeStream struct {
	Index     int    `json:"index"`
	CodecType string `json:"codec_type"`
	CodecName string `json:"codec_name"`
	Width     int    `json:"width"`
	Height    int    `json:"height"`
	Channels  int    `json:"channels"`
	Tags      struct {
		Language string `json:"language"`
	} `json:"tags"`
}

// Run executes ffprobe on the given file and returns parsed metadata.
func Run(path string) (*ProbeResult, error) {
	cmd := exec.Command("ffprobe",
		"-v", "quiet",
		"-print_format", "json",
		"-show_format",
		"-show_streams",
		path,
	)

	out, err := cmd.Output()
	if err != nil {
		return nil, fmt.Errorf("ffprobe failed: %w", err)
	}

	var raw ffprobeOutput
	if err := json.Unmarshal(out, &raw); err != nil {
		return nil, fmt.Errorf("ffprobe parse failed: %w", err)
	}

	result := &ProbeResult{}

	if d, err := strconv.ParseFloat(raw.Format.Duration, 64); err == nil {
		result.Duration = d
	}
	if br, err := strconv.ParseInt(raw.Format.BitRate, 10, 64); err == nil {
		result.Bitrate = br
	}

	for _, s := range raw.Streams {
		switch s.CodecType {
		case "video":
			if result.VideoCodec == "" {
				result.VideoCodec = s.CodecName
				result.Width = s.Width
				result.Height = s.Height
			}
		case "audio":
			result.Audio = append(result.Audio, AudioTrack{
				Index:    s.Index,
				Codec:    s.CodecName,
				Language: s.Tags.Language,
				Channels: s.Channels,
			})
		case "subtitle":
			result.Subtitles = append(result.Subtitles, SubTrack{
				Index:    s.Index,
				Codec:    s.CodecName,
				Language: s.Tags.Language,
			})
		}
	}

	return result, nil
}