#!/bin/busybox ash
set -euo pipefail

cd "$(dirname "$0")"

lecture=test_render
mkdir -p "$lecture"
rm "$lecture"/* || true

for file in *.mp4; do echo "file '$(realpath "$file")'" >>"$lecture/recording.txt"; done

function write_svg() {
	echo '<svg viewBox="0 0 1920 1080" width="1920" height="1080">'
	echo '  <rect fill="black" x="0" y="0" width="1920" height="1080"/>'
	echo '  <text x="960" y="540" fill="white" text-anchor="middle" dominant-baseline="hanging" font-family="Noto Sans">'
	echo "    $1"
	echo '  </text>'
	echo '</svg>'
}

write_svg Intro >"$lecture/intro.svg"
write_svg Outro >"$lecture/outro.svg"

set -x

ffmpeg \
	-hide_banner \
	-f concat \
	-safe 0 \
	-i "$lecture/recording.txt" \
	-af "loudnorm,pan=stereo|c0=c0|c1=c0,aformat=sample_rates=48000" \
	-c:v copy -b:a 128000 \
	"$lecture/recording.mp4"

ffmpeg \
	-hide_banner \
	-vaapi_device /dev/dri/renderD128 \
	-loop 1 -i "$lecture/intro.svg" \
	-filter_complex "[0]format=nv12,hwupload[v];aevalsrc=0:s=48000[a]" \
	-map "[v]" -map "[a]" \
	-c:v h264_vaapi -r 25 -t 3 -b:a 128000 \
	"$lecture/intro.mp4"

ffmpeg \
	-hide_banner \
	-vaapi_device /dev/dri/renderD128 \
	-loop 1 -i "$lecture/outro.svg" \
	-filter_complex "[0]format=nv12,hwupload[v];aevalsrc=0:s=48000[a]" \
	-map "[v]" -map "[a]" \
	-c:v h264_vaapi -r 25 -t 5 -b:a 128000 \
	"$lecture/outro.mp4"

#convert -background none -density 1000 -resize 150x ../assets/logo.svg "$lecture/logo.png"
#convert -background none -density 1000 -resize 128x ../assets/fastforward.svg "$lecture/fastforward.png"

inkscape -w 150 -h 150 ../assets/logo.svg -o "$lecture/logo.png"
inkscape -w 128 -h 128 ../assets/fastforward.svg -o "$lecture/fastforward.png"

ffmpeg \
	-hide_banner \
	-vaapi_device /dev/dri/renderD128 \
	-i "$lecture/intro.mp4" \
	-i "$lecture/recording.mp4" \
	-i "$lecture/outro.mp4" \
	-i "$lecture/logo.png" \
	-i "$lecture/fastforward.png" \
	-async 1 \
	-filter_complex "
			[1:v]trim=start=2:duration=8,setpts=PTS-STARTPTS[v_tmp0];
			[1:a]atrim=start=2:duration=8,asetpts=PTS-STARTPTS[a_tmp0];

			[v_tmp0]split=3[t0_v_tmp1][t1_v_tmp1][t2_v_tmp1];
			[t0_v_tmp1]trim=duration=3[t3_v_tmp1];
			[t1_v_tmp1]trim=start=3:duration=2,setpts=PTS-STARTPTS,setpts=PTS/3[t4_v_tmp1];
			[t4_v_tmp1][4]overlay=x=main_w/2-overlay_w/2:y=main_h/2-overlay_h/2[t6_v_tmp1];
			[t2_v_tmp1]trim=start=5,setpts=PTS-STARTPTS[t5_v_tmp1];
			[a_tmp0]asplit=3[t0_a_tmp1][t1_a_tmp1][t2_a_tmp1];
			[t0_a_tmp1]atrim=duration=3[t3_a_tmp1];
			[t1_a_tmp1]atrim=start=3:duration=2,asetpts=PTS-STARTPTS,atempo=3[t4_a_tmp1];
			[t2_a_tmp1]atrim=start=5,asetpts=PTS-STARTPTS[t5_a_tmp1];
			[t3_v_tmp1][t3_a_tmp1][t6_v_tmp1][t4_a_tmp1][t5_v_tmp1][t5_a_tmp1]concat=n=3:v=1:a=1[v_tmp1][a_tmp1];

			[0:v][0:a][v_tmp1][a_tmp1][2:v][2:a]concat=n=3:v=1:a=1[v_tmp2][a_tmp2];

			[3]format=yuva444p,colorchannelmixer=aa=0.5[logo];
			[v_tmp2][logo]overlay=x=main_w-overlay_w-130:y=main_h-overlay_h-65[v_tmp3];
			[a_tmp2]anull[a_tmp3];
			
			[v_tmp3]format=nv12,hwupload[final_v];
			[a_tmp3]anull[final_a]
		" \
	-map '[final_v]' -map '[final_a]' \
	-c:v h264_vaapi -rc_mode CQP -global_quality 22 \
	-c:a aac -b:a 128000 \
	"$lecture/$lecture.mp4"