#!/bin/bash
# 4-seasons.sh — create one daily clip from yesterday's images, sized to its
# share of the corresponding Vivaldi movement's music duration.
#
# On the last day of a movement period, automatically runs montage-mvt.sh to
# compile the full movement montage.
#
# Run once per day from cron (e.g. 01:00 daily).

set -euo pipefail

SCRIPT_DIR="$(dirname "$(realpath "$0")")"
source "$SCRIPT_DIR/sky-cam.conf"
export TIMEZONE   # make it visible to season_info.py subprocess

# Camera name: required first argument (systemd passes it via ExecStart).
# Date: optional second argument (YYYY-MM-DD); defaults to yesterday.
CAM_NAME="${1:-}"
DATE_ARG="${2:-}"
if [ -z "$CAM_NAME" ]; then
    echo "Usage: $0 <camera-name> [YYYY-MM-DD]"
    echo "  e.g. $0 east"
    echo "       $0 east 2026-04-20"
    exit 1
fi

# ── Configuration ──────────────────────────────────────────────────────────────
base_dir="$BASE_DIR"
music_base_dir="$MUSIC_DIR"
[ ! -d "$music_base_dir" ] && music_base_dir="$SCRIPT_DIR/music"

# ── Date setup ────────────────────────────────────────────────────────────────
if [ -n "$DATE_ARG" ]; then
    yesterday=$(date --date="$DATE_ARG" +%Y-%m-%d)
else
    yesterday=$(date --date="yesterday" +%Y-%m-%d)
fi
echo "Processing: $yesterday"

# ── Season / movement info from astronomical calculation ──────────────────────
_season_info="$(python3 "$SCRIPT_DIR/season_info.py" "$yesterday")" || {
    echo "Error: season_info.py failed — check Python dependencies (pytz)"
    exit 1
}
eval "$_season_info"
# Provides: SEASON  MVT_NUM  DAY_OF_MVT  DAYS_IN_MVT  MVT_START  MVT_END
#           IS_LAST_DAY  ASTRO_YEAR
echo "Season=$SEASON  Mvt=$MVT_NUM  Year=$ASTRO_YEAR  Day=$DAY_OF_MVT/$DAYS_IN_MVT  LastDay=$IS_LAST_DAY"

# ── Locate music file and get its duration ────────────────────────────────────
music_file=$(find "$music_base_dir" -type f -iname "*${SEASON}*" \
    | grep -iE "Mvt[^0-9]*${MVT_NUM}[^0-9]" | sort | head -n 1)
if [ -z "$music_file" ] || [ ! -f "$music_file" ]; then
    echo "ERROR: Music file not found for $SEASON Mvt $MVT_NUM in $music_base_dir"
    exit 1
fi
music_duration=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$music_file")
echo "Music: $(basename "$music_file")  ($music_duration s)"

# Each daily clip covers (music_duration * loops) / DAYS_IN_MVT seconds.
# Short movements use loops > 1 so each day gets more screen time.
loops_var="MONTAGE_MUSIC_LOOPS_${SEASON}_${MVT_NUM}"
loops="${!loops_var:-${MONTAGE_MUSIC_LOOPS:-1}}"
target_per_clip=$(echo "scale=6; $music_duration * $loops / $DAYS_IN_MVT" | bc)
echo "Target clip duration: $target_per_clip s  ($DAYS_IN_MVT days in movement, ${loops}x music)"

# ── Locate yesterday's images ─────────────────────────────────────────────────
image_dir="$base_dir/$CAM_NAME/$yesterday"

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

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

# ── Per-camera capture interval ───────────────────────────────────────────────
interval_var="CAPTURE_INTERVAL_${CAM_NAME}"
INTERVAL="${!interval_var:-${CAPTURE_INTERVAL:-10}}"

# ── Prepare output directory ──────────────────────────────────────────────────
output_dir="$MOVIES_DIR/$CAM_NAME/$ASTRO_YEAR/$SEASON/Mvt$MVT_NUM"
mkdir -p "$output_dir"

# ── Build sorted image list ───────────────────────────────────────────────────
temp_file=$(mktemp --suffix=.txt)
temp_video="$output_dir/${yesterday}_Mvt${MVT_NUM}-temp.mp4"
cleanup() { rm -f "$temp_file" "$temp_video" 2>/dev/null || true; }
trap cleanup EXIT

mapfile -t all_images < <(find "$image_dir" -type f -name "*.jpg" | sort)

# Validate each frame: skip empty files and optionally uniform-colour bad-signal frames.
# SEASONS_GREY_STDDEV_MIN=0 (default) disables the content check entirely.
# When enabled, large files (> SEASONS_LARGE_FRAME_BYTES, default 1 MB) are trusted
# as good without running the expensive ImageMagick check — only sub-1MB frames
# are inspected.  This keeps the filter fast even on days with 40k+ images.
GREY_MIN="${SEASONS_GREY_STDDEV_MIN:-0}"
GREY_DARK_FLOOR="${SEASONS_GREY_DARK_FLOOR:-30}"
LARGE_BYTES="${SEASONS_LARGE_FRAME_BYTES:-1048576}"  # files above this skip content check
total_frames=${#all_images[@]}
images=(); bad=0; grey=0; checked=0
if [ "$GREY_MIN" != "0" ]; then
    echo "Validating $total_frames frames (grey-filter active: stddev<${GREY_MIN}, mean>${GREY_DARK_FLOOR})..."
else
    echo "Validating $total_frames frames..."
fi
for img in "${all_images[@]}"; do
    ((checked++)) || true
    if (( checked % 500 == 0 || checked == total_frames )); then
        echo "  $checked / $total_frames frames checked..."
    fi
    # Skip empty or unreadable files (0-byte writes from camera reconnects)
    if [ ! -r "$img" ] || [ ! -s "$img" ]; then
        echo "WARNING: skipping empty/missing frame: $(basename "$img")"
        ((bad++)) || true; continue
    fi
    # Optional: skip uniform-colour bad-signal frames (green, grey, etc.).
    # Only runs ImageMagick on files below SEASONS_LARGE_FRAME_BYTES — large files
    # are always good and skip the check entirely.
    if [ "$GREY_MIN" != "0" ] && command -v convert &>/dev/null; then
        fsize=$(stat -c%s "$img" 2>/dev/null || echo 0)
        if [ "$fsize" -lt "$LARGE_BYTES" ]; then
            read -r stddev mean < <(convert "$img" -colorspace Gray \
                -format "%[fx:int(standard_deviation*255)] %[fx:int(mean*255)]" \
                info: 2>/dev/null || echo "255 128") || true
            if [ "${stddev:-255}" -lt "$GREY_MIN" ] && [ "${mean:-0}" -gt "$GREY_DARK_FLOOR" ]; then
                ((grey++)) || true; continue
            fi
        fi
    fi
    images+=("$img")
done
[ "$bad"  -gt 0 ] && echo "WARNING: skipped $bad corrupt/empty frame(s) of ${#all_images[@]}" || true
[ "$grey" -gt 0 ] && echo "INFO: skipped $grey grey/uniform frame(s) (SEASONS_GREY_STDDEV_MIN=${GREY_MIN})" || true

if [ "${#images[@]}" -eq 0 ]; then
    echo "ERROR: no valid images remain after filtering — skipping $yesterday."
    exit 0
fi
echo "Validation done: ${#images[@]} valid frames"

for img in "${images[@]}"; do
    printf "file '%s'\nduration 0.04\n" "$img"
done > "$temp_file"
# ffmpeg concat demuxer requires a final entry with no duration for image files
printf "file '%s'\n" "${images[-1]}" >> "$temp_file"

# ── Step 1: Build raw video ───────────────────────────────────────────────────
echo "Step 1/2: encoding raw video from ${#images[@]} frames (may take several minutes)..."
ffmpeg -loglevel warning \
    -f concat -safe 0 -i "$temp_file" \
    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_SEASONS_RAW" -vsync 2 -an \
    -y "$temp_video"

raw_duration=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$temp_video")
echo "Raw duration: $raw_duration s"

# ── Step 2: Speed-adjust to target clip duration ──────────────────────────────
speed_factor=$(echo "scale=6; $raw_duration / $target_per_clip" | bc)
echo "Step 2/2: speed factor ${speed_factor}x → ${target_per_clip}s target..."

final_file="$output_dir/${CAM_NAME}-${yesterday}_Mvt${MVT_NUM}-Day${DAY_OF_MVT}of${DAYS_IN_MVT}-final.mp4"
if ! ffmpeg -loglevel warning \
    -i "$temp_video" \
    -vf "setpts=PTS/$speed_factor,fps=25" \
    -c:v libx264 -pix_fmt yuv420p -preset "$ENCODE_PRESET" -crf "$CRF_SEASONS_FINAL" \
    -t "$target_per_clip" -an \
    -y "$final_file"; then
    rm -f "$final_file"
    "$SCRIPT_DIR/notify.sh" "FAILED: [$CAM_NAME] $SEASON Mvt$MVT_NUM Day$DAY_OF_MVT speed-adjust ($yesterday)" \
        "ffmpeg speed-adjust failed — re-run 4-seasons.sh $CAM_NAME while JPGs exist" || true
    exit 1
fi

adjusted=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$final_file")
echo "Daily clip: $final_file  ($adjusted s)"

# Warn if clip duration deviates more than 0.5 s from target (float drift check)
drift=$(echo "scale=3; $adjusted - $target_per_clip" | bc | sed 's/^-//')
if awk "BEGIN{exit !($drift > 0.5)}"; then
    echo "WARNING: clip duration ${adjusted}s differs from target ${target_per_clip}s by ${drift}s"
    "$SCRIPT_DIR/notify.sh" "WARNING: [$CAM_NAME] $SEASON Mvt$MVT_NUM Day$DAY_OF_MVT duration drift ($yesterday)" \
        "Clip ${adjusted}s vs target ${target_per_clip}s (drift ${drift}s)" || true
fi

"$SCRIPT_DIR/notify.sh" "[$CAM_NAME] $SEASON Mvt$MVT_NUM Day$DAY_OF_MVT/$DAYS_IN_MVT saved ($yesterday)" \
    "$(basename "$final_file") — ${adjusted}s | $final_file" || true

# ── Auto-trigger montage on last day of movement ──────────────────────────────
if [ "$IS_LAST_DAY" = "true" ]; then
    echo "Last day of $SEASON Mvt $MVT_NUM — triggering montage compilation..."
    # Pass $yesterday so montage-mvt.sh looks up the correct movement
    # (running the next morning, "today" would already be the next movement).
    "$SCRIPT_DIR/montage-mvt.sh" "$CAM_NAME" "$yesterday"
fi