#!/bin/bash

# Configuration
SOURCEDIR=$(pwd)
PROJECT=$1
BASETEMPLATE="nluug-title-template.svg"
SOURCEFILE="event.svg"
VIDEODIR="${SOURCEDIR}/output"
PROJDIR="/tmp/nluug-intro-${PROJECT}"
CONV="convert -background black -fill black -alpha off"
FRAMENUM=0

# Validate input
validate_input() {
    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
}

# Setup project directory
setup_project_dir() {
    mkdir -p "${PROJDIR}" || { echo "Failed to create project directory"; exit 1; }
    cd "${PROJDIR}" || { echo "Failed to change to project directory"; exit 1; }
}

# Generate frames
generate_frames() {
    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}
    for i in $(seq 0 ${SLEN}); do
        echo "Generate frame ${FRAMENUM}"
        SN="${SPEAKERNAME:0:i}"
        awk -v sn="$SN" '{gsub(/TITLE[123]/, ""); gsub(/SPEAKERSPEAKERSPEAKERSPEAKER/, sn); print}' ${SOURCEFILE} > "${PROJDIR}/frame-${FRAMENUM}.svg"
        ${CONV} "frame-${FRAMENUM}.svg" "frame-${FRAMENUM}.webp"
        ((FRAMENUM++))
    done

    echo "Add title sequence"
    for i in $(seq 0 40); do
        echo "Generate frame ${FRAMENUM}"
        T1="${TITLE1:0:i}"
        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(/SPEAKERSPEAKERSPEAKERSPEAKER/, sn); print}' ${SOURCEFILE} > "${PROJDIR}/frame-${FRAMENUM}.svg"
        ${CONV} "frame-${FRAMENUM}.svg" "frame-${FRAMENUM}.webp"
        ((FRAMENUM++))
    done

    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(/SPEAKERSPEAKERSPEAKERSPEAKER/, sn); print}' ${SOURCEFILE} > "${PROJDIR}/frame-${FRAMENUM}.svg"
    ${CONV} "frame-${FRAMENUM}.svg" "frame-${FRAMENUM}.webp"
    LASTFRAME=$FRAMENUM
    ((FRAMENUM++))

    for i in $(seq 0 1 100); do
        echo "Duplicating frame ${FRAMENUM}"
        cp "frame-${LASTFRAME}.webp" "frame-${FRAMENUM}.webp"
        ((FRAMENUM++))
    done

    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
}

# Render video
render_video() {
    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"
}

# Cleanup temporary files
cleanup() {
    echo "Cleaning up temporary files"
    rm -rf "${PROJDIR}"
}

# Main execution
main() {
    validate_input
    setup_project_dir

    # 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(/SPEAKERSPEAKERSPEAKERSPEAKER/, ""); gsub(/TITLE[123]/, ""); print}' ${SOURCEFILE} > frameclear.svg

    generate_frames
    render_video
    cleanup
}

main