package main

import (
	"fmt"
	"io"
	"sort"
	"time"
)

func secs_to_ass_time(secs float64) string {
	dur := time.Duration(secs) * time.Second

	hh := int64(dur.Hours())
	mm := int64(dur.Minutes()) - (hh * 60)
	ss := int64(dur.Seconds()) - (hh * 3600) - (mm * 60)
	ms := int64(dur.Milliseconds()) - (hh * 3600000) - (mm * 60000) - (ss * 1000)

	return fmt.Sprintf("%02d:%02d:%02d.%03d", hh, mm, ss, ms)
}

// WriteSubtitle streams the video subtitles to the supplied writer in ASS format.
func (ltc *loadTupContent) WriteSubtitle(w io.Writer, totalVideoDurationSecs float64) error {

	w.Write([]byte(`[Script Info]
; Script generated by loadtup-dl
ScriptType: v4.00+
Collisions: Normal
Timer: 100,0000
WrapStyle: 3
 
[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Default, Arial,16,&H00FFFFFF,&H00FFFFFF,&H00000008,&H80000008,-1,0,0,0,100,100,0.00,0.00,1,1.00,2.00,2,10,10,10,0
Style: TLNote, Arial,10,&H00FFFFFF,&H00FFFFFF,&H00000008,&H80000008,-1,0,0,0,100,100,0.00,0.00,1,1.00,2.00,8,10,10,10,0

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
`))

	type entry struct {
		startTime float64
		entry     string
	}
	entries := make([]entry, 0, len(ltc.Caps)+len(ltc.Scrcaps))

	for i := 0; i < len(ltc.Caps); i += 1 {
		if ltc.Caps[i] == "" {
			// Don't show anything
			continue
		}

		start := secs_to_ass_time(ltc.Secs[i])
		var end string
		if i < len(ltc.Caps)-1 {
			end = secs_to_ass_time(ltc.Secs[i+1])
		} else {
			// The final subtitle. Loadtup displays these for the entire
			// remaining video duration
			end = secs_to_ass_time(totalVideoDurationSecs)
		}

		// Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
		entries = append(entries, entry{
			startTime: ltc.Secs[i],
			entry:     fmt.Sprintf("Dialogue: 0,%s,%s,Default,,0000,0000,0000,,%s\n", start, end, ltc.Caps[i]),
		})

	}

	// Repeat for scrcaps, using top positioning and a different layer

	for i := 0; i < len(ltc.Scrcaps); i += 1 {
		if ltc.Caps[i] == "" {
			// Don't show anything
			continue
		}

		start := secs_to_ass_time(ltc.Scrsecs[i])
		var end string
		if i < len(ltc.Scrcaps)-1 {
			end = secs_to_ass_time(ltc.Scrsecs[i+1])
		} else {
			// The final subtitle. Loadtup displays these for the entire
			// remaining video duration
			end = secs_to_ass_time(totalVideoDurationSecs)
		}

		// Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
		entries = append(entries, entry{
			startTime: ltc.Scrsecs[i],
			entry:     fmt.Sprintf("Dialogue: 1,%s,%s,TLNote,,0000,0000,0000,,%s\n", start, end, ltc.Scrcaps[i]),
		})
	}

	// Sort all the entries by their start time, to mingle TL note entries
	// properly with the other subtitles
	sort.SliceStable(entries, func(i, j int) bool {
		return entries[i].startTime < entries[j].startTime
	})

	// Emit all to writer
	for _, e := range entries {
		w.Write([]byte(e.entry))
	}

	return nil
}