#!/bin/bash
# fullday-video.sh — create a natural-speed timelapse of yesterday's full day of
# images at a fixed frame rate.  Files older than RETENTION_DAYS are deleted
# automatically.  Sunrise 10-second uploads and montage videos are NOT touched.
#
# Run once per day from cron (e.g. 02:00 daily, after 4-seasons.sh).

set -euo pipefail

SCRIPT_DIR="$(dirname "$(realpath "$0")")"
source "$SCRIPT_DIR/sky-cam.conf"

# Camera name: first argument overrides conf (systemd passes it via ExecStart).
CAM_NAME="${1:-$SUNRISE_CAM}"

# ── Configuration ──────────────────────────────────────────────────────────────
base_dir="$BASE_DIR"
# FULLDAY_FPS and RETENTION_DAYS come from sky-cam.conf

# ── Date / paths ──────────────────────────────────────────────────────────────
yesterday=$(date --date="yesterday" +%Y-%m-%d)
image_dir="$base_dir/$CAM_NAME/$yesterday"
output_dir="$MOVIES_DIR/$CAM_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 in $image_dir — skipping."
    exit 0
fi

frame_dur=$(echo "scale=6; 1 / $FULLDAY_FPS" | bc)
approx_min=$(echo "scale=1; $num_images / $FULLDAY_FPS / 60" | bc)
echo "Images: $num_images at ${FULLDAY_FPS} fps  ≈ ${approx_min} min"

# ── Build concat list with per-frame duration ─────────────────────────────────
# The concat demuxer needs an explicit duration per image; the last file is
# repeated without a duration to correctly anchor the final frame's pts.
temp_list=$(mktemp --suffix=.txt)
trap 'rm -f "$temp_list"' EXIT

find "$image_dir" -type f -name "*.jpg" | sort | while read -r img; do
    printf "file '%s'\nduration %s\n" "$img" "$frame_dur"
done > "$temp_list"

# Append last image again (required by ffmpeg concat demuxer for images)
last_img=$(find "$image_dir" -type f -name "*.jpg" | sort | tail -n 1)
printf "file '%s'\n" "$last_img" >> "$temp_list"

# ── Encode — native camera resolution, no audio ───────────────────────────────
output_file="$output_dir/${yesterday}-fullday.mp4"
echo "Creating: $output_file"

ffmpeg -loglevel warning \
    -f concat -safe 0 -i "$temp_list" \
    -c:v libx264 -pix_fmt yuv420p -crf "$CRF_FULLDAY" \
    -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 / $(echo "scale=1; $actual_dur/60" | bc) min)"