package main

import (

"encoding/json"

"os/exec"

"strconv"

"sync"

)

// ffprobeMissing caches the "ffprobe not on PATH" result so a bulk album doesn't

// fork-exec N times just to fail identically.

var ffprobeMissing sync.Once

var ffprobeAbsent bool

// probeVideo runs ffprobe to extract video width, height, and duration in seconds.

// Returns ok=false if ffprobe is missing or the file has no video stream.

func probeVideo(path string) (w, h int, durSec float64, ok bool) {

ffprobeMissing.Do(func() {

if _, err := exec.LookPath("ffprobe"); err != nil {

ffprobeAbsent = true

}

})

if ffprobeAbsent {

return 0, 0, 0, false

}

type ffStream struct {

CodecType string `json:"codec_type"`

Width int `json:"width"`

Height int `json:"height"`

Duration string `json:"duration"`

}

type ffFormat struct {

Duration string `json:"duration"`

}

type ffOut struct {

Streams []ffStream `json:"streams"`

Format ffFormat `json:"format"`

}

cmd := exec.Command("ffprobe",

"-v", "error",

"-print_format", "json",

"-show_streams",

"-show_format",

path,

)

out, err := cmd.Output()

if err != nil {

return 0, 0, 0, false

}

var data ffOut

if jerr := json.Unmarshal(out, &data); jerr != nil {

return 0, 0, 0, false

}

var width, height int

var durStr string

for _, s := range data.Streams {

if s.CodecType == "video" && s.Width > 0 && s.Height > 0 {

width, height = s.Width, s.Height

if s.Duration != "" {

durStr = s.Duration

}

break

}

}

if width == 0 || height == 0 {

return 0, 0, 0, false

}

if durStr == "" {

durStr = data.Format.Duration

}

dur, _ := strconv.ParseFloat(durStr, 64)

return width, height, dur, true

}