#!/bin/bash
# fullday-video.sh — create an ~30-minute timelapse of yesterday's full day of
# images.  Files older than 10 days are deleted automatically to save space.
# Run once per day (e.g. from cron at 02:00, after 4-seasons.sh).

set -euo pipefail

# ── Configuration ──────────────────────────────────────────────────────────────
base_dir="/home/motion/drives/local-2tb"
script_name=$(basename "$(dirname "$(realpath "$0")")" | cut -d'-' -f1)

TARGET_DURATION=1800   # target video length in seconds (~30 min)
MIN_FRAME_DUR=0.016667 # max 60 fps
MAX_FRAME_DUR=10.0     # min 0.1 fps (10 s per frame)
RETENTION_DAYS=10

TARGET_W=1280
TARGET_H=720

# ── Date / paths ──────────────────────────────────────────────────────────────
yesterday=$(date --date="yesterday" +%Y-%m-%d)
image_dir="$base_dir/$script_name/$yesterday"
output_dir="$base_dir/movies/$script_name/fullday"
mkdir -p "$output_dir"

# ── Purge old full-day videos ─────────────────────────────────────────────────
echo "Removing full-day videos older than $RETENTION_DAYS days..."
find "$output_dir" -maxdepth 1 -name "*-fullday.mp4" -mtime "+$RETENTION_DAYS" -delete

# ── Sanity checks ─────────────────────────────────────────────────────────────
if [ ! -d "$image_dir" ]; then
    echo "WARNING: Image directory $image_dir not found — skipping."
    exit 0
fi

num_images=$(find "$image_dir" -type f -name "*.jpg" | wc -l)
if [ "$num_images" -lt 1 ]; then
    echo "WARNING: No images found in $image_dir — skipping."
    exit 0
fi
echo "Images: $num_images"

# ── Calculate per-frame duration to hit TARGET_DURATION ───────────────────────
frame_dur=$(echo "scale=6; $TARGET_DURATION / $num_images" | bc)

# Clamp to [MIN_FRAME_DUR, MAX_FRAME_DUR]
if (( $(echo "$frame_dur < $MIN_FRAME_DUR" | bc -l) )); then frame_dur=$MIN_FRAME_DUR; fi
if (( $(echo "$frame_dur > $MAX_FRAME_DUR" | bc -l) )); then frame_dur=$MAX_FRAME_DUR; fi

fps=$(echo "scale=4; 1 / $frame_dur" | bc)
approx_min=$(echo "scale=1; $num_images * $frame_dur / 60" | bc)
echo "Frame duration: ${frame_dur}s  (fps=${fps})  ≈ ${approx_min} min"

# ── Build concat list with per-frame duration ─────────────────────────────────
# The concat demuxer requires the last file to be repeated without a duration.
temp_list=$(mktemp --suffix=.txt)
trap 'rm -f "$temp_list"' EXIT

last_img=""
find "$image_dir" -type f -name "*.jpg" | sort | while read -r img; do
    echo "file '$img'"
    echo "duration $frame_dur"
    last_img="$img"
done > "$temp_list"

# Append last image again (required by concat demuxer to set final frame pts)
last_img=$(find "$image_dir" -type f -name "*.jpg" | sort | tail -n 1)
echo "file '$last_img'" >> "$temp_list"

# ── Encode ────────────────────────────────────────────────────────────────────
output_file="$output_dir/${yesterday}-fullday.mp4"
echo "Creating full-day video: $output_file"

ffmpeg -loglevel warning \
    -f concat -safe 0 -i "$temp_list" \
    -vf "scale=${TARGET_W}:${TARGET_H}:force_original_aspect_ratio=decrease,\
pad=${TARGET_W}:${TARGET_H}:(ow-iw)/2:(oh-ih)/2,setsar=1" \
    -c:v libx264 -pix_fmt yuv420p -crf 28 \
    -an -y "$output_file"

actual_dur=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$output_file")
echo "Done: $output_file  (${actual_dur}s)"