#!/bin/bash

SOURCEDIR=$(pwd)
PROJECT=$1
BASETEMPLATE="nluug-title-template.svg"
SOURCEFILE="event.svg"
VIDEODIR=${SOURCEDIR}/output
PROJDIR=/tmp/nluug-intro-${PROJECT}

if [ -z "${PROJECT}" ]; then
    echo "Usage: $0 <project>"
    exit 1
fi

if [ -z "$EVENTNAME" ]; then
    echo "Specify EVENTNAME env-var"
    exit 2
fi
if [ -z "$SPEAKERNAME" ]; then
    echo "Specify SPEAKERNAME env-var"
    exit 3
fi
if [ -z "$TITLE1" ] || [ -z "$TITLE2" ] || [ -z "$TITLE3" ]; then
    echo "Specify TITLE1/TITLE2/TITLE3 env-vars"
    exit 4
fi

# Usage:
# EVENTNAME="NLUUG Najaar 5 November 2024"
# MAXLENGTH="SPEAKERSPEAKERSPEAKERSPEAKERSPEAKER"
#SPEAKERNAME="Example Speaker Name"
#TITLE1="Keynote: Some example title"
#TITLE2="With 3 lines, or use some whitespace"
#TITLE3="If less are needed"

CONV="convert -background black -fill black -alpha off"
FRAMENUM=0

# Make project directory
mkdir -p ${PROJDIR}; cd ${PROJDIR}

# Customize template to this event from base template
awk -v eventname="$EVENTNAME" '{gsub(/EVENTNAMEEVENTNAME/, eventname); print}' "${SOURCEDIR}/${BASETEMPLATE}" > ${SOURCEFILE}

# Create initial image without title/speaker info
awk '{gsub(/SPEAKERSPEAKERSPEAKERSPEAKERSPEAKER/, ""); gsub(/TITLE[123]/, ""); print}' ${SOURCEFILE} > frameclear.svg

# Fade this image in from 100% transparent to 'normal'
echo "Generate fade-in-from-black sequence"
for i in $(seq 100 -3 0)
do
    echo "Generate frame ${FRAMENUM}"
    ${CONV} -colorize ${i}% frameclear.svg frame-${FRAMENUM}.webp
    ((FRAMENUM++))
done

echo "Add speakername sequence"
SLEN=${#SPEAKERNAME} # Length of name
# Copy a new frame, and fill in the speaker name 1 character at a time
for i in $(seq 0 ${SLEN})
do
    echo "Generate frame ${FRAMENUM}"
    SN="${SPEAKERNAME:0:i}"
    awk -v sn="$SN" '{gsub(/TITLE[123]/, ""); gsub(/SPEAKERSPEAKERSPEAKERSPEAKERSPEAKER/, sn); print}' ${SOURCEFILE} > ${PROJDIR}/frame-${FRAMENUM}.svg
    ${CONV} frame-${FRAMENUM}.svg frame-${FRAMENUM}.webp
    ((FRAMENUM++))
done

echo "Add title sequence"
# With speakername, now add the title, 1 char (per line) at a time
for i in $(seq 0 40)
do
    echo "Generate frame ${FRAMENUM}"
    T1="${TITLE1:0:i}"  # Substring, first i characters
    T2="${TITLE2:0:i}"
    T3="${TITLE3:0:i}"
    awk -v t1="$T1" -v t2="$T2" -v t3="$T3" -v sn="$SN" '{gsub(/TITLE1/, t1); gsub(/TITLE2/, t2); gsub(/TITLE3/, t3); gsub(/SPEAKERSPEAKERSPEAKERSPEAKERSPEAKER/, sn); print}' ${SOURCEFILE} > ${PROJDIR}/frame-${FRAMENUM}.svg
    ${CONV} frame-${FRAMENUM}.svg frame-${FRAMENUM}.webp
    ((FRAMENUM++))
done

# Generate final frame, with full speakername + title
echo "Generate completed title"
awk -v t1="$TITLE1" -v t2="$TITLE2" -v t3="$TITLE3" -v sn="$SPEAKERNAME" '{gsub(/TITLE1/, t1); gsub(/TITLE2/, t2); gsub(/TITLE3/, t3); gsub(/SPEAKERSPEAKERSPEAKERSPEAKERSPEAKER/, sn); print}' ${SOURCEFILE} > ${PROJDIR}/frame-${FRAMENUM}.svg
${CONV} frame-${FRAMENUM}.svg frame-${FRAMENUM}.webp
LASTFRAME=$FRAMENUM
((FRAMENUM++))

# Now copy the rendered output of the last frame a few more times so we can read it before the video ends
for i in $(seq 0 1 100)
do
    echo "Duplicating frame ${FRAMENUM}"
    cp frame-${LASTFRAME}.webp frame-${FRAMENUM}.webp
    ((FRAMENUM++))
done

# Fade this image out over 100 frames back to the normal view
echo "Generate fade-out-sequence"
for i in $(seq 0 3 100)
do
    echo "Generate frame ${FRAMENUM}"
    ${CONV} -colorize ${i}% frame-${LASTFRAME}.svg frame-${FRAMENUM}.webp
    ((FRAMENUM++))
done

echo "Rendering to video"
ffmpeg -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=44100 -framerate 25 -i frame-%d.webp -c:a aac -c:v libx264 -shortest -profile:v baseline -pix_fmt yuv420p -colorspace:v 'bt709' -color_primaries:v 'bt709' -color_trc:v 'bt709' -color_range:v 'tv' -r 30 ${VIDEODIR}/${PROJECT}-x264.mkv