#!/bin/bash
# year-end-join.sh — concatenate all 12 movement montages for one astronomical
# year into a single "Four Seasons" video.
#
# Called automatically by montage-mvt.sh after the last Autumn movement finishes.
# Can also be run manually:  ./year-end-join.sh 2025
#
# The 12 individual movement videos already carry their own attribution overlay
# (first 6 seconds of each), so no extra card is appended here.
#
# Output: $MOVIES_DIR/$CAM_NAME/$ASTRO_YEAR/$CAM_NAME-$ASTRO_YEAR.mp4

set -euo pipefail

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

ASTRO_YEAR="${1:-}"
if [ -z "$ASTRO_YEAR" ]; then
    echo "Usage: $0 <ASTRO_YEAR> [CAM_NAME]  (e.g. $0 2025 north)"
    exit 1
fi
CAM_NAME="${2:-}"
if [ -z "$CAM_NAME" ]; then
    echo "Usage: $0 <ASTRO_YEAR> <CAM_NAME>  (e.g. $0 2025 north)"
    exit 1
fi

year_dir="$MOVIES_DIR/$CAM_NAME/$ASTRO_YEAR"

echo "Assembling Four Seasons $ASTRO_YEAR from $year_dir ..."

# ── Collect the 12 montage files in season/movement order ────────────────────
concat_list=$(mktemp --suffix=.txt)
trap 'rm -f "$concat_list"' EXIT

missing=0
total_expected_dur=0
for season in Winter Spring Summer Autumn; do
    for mvt in 1 2 3; do
        mvt_dir="$year_dir/$season/Mvt$mvt/montage"
        # Pick the newest (or only) montage file for this movement
        f=$(find "$mvt_dir" -maxdepth 1 -name "*-Montage.mp4" 2>/dev/null | sort | tail -1)
        if [ -z "$f" ]; then
            echo "WARNING: missing montage for $season Mvt$mvt ($mvt_dir)"
            missing=$((missing + 1))
        else
            d=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$f")
            total_expected_dur=$(echo "scale=3; $total_expected_dur + $d" | bc)
            echo "  $season Mvt$mvt → $(basename "$f")  (${d}s)"
            printf "file '%s'\n" "$f" >> "$concat_list"
        fi
    done
done
echo "Expected total duration: ${total_expected_dur}s ($(echo "scale=1; $total_expected_dur/60" | bc) min)"

found=$(wc -l < "$concat_list")
echo "$found of 12 movements found  ($missing missing)"

if [ "$found" -eq 0 ]; then
    echo "ERROR: no montage files found — aborting."
    exit 1
fi

if [ "$missing" -gt 0 ]; then
    echo "WARNING: joining with $missing movement(s) absent."
fi

# ── Join ──────────────────────────────────────────────────────────────────────
output_file="$year_dir/${CAM_NAME}-${ASTRO_YEAR}.mp4"
echo "Output: $output_file"

if ! ffmpeg -loglevel warning \
    -f concat -safe 0 -i "$concat_list" \
    -c copy -y "$output_file"; then
    "$SCRIPT_DIR/notify.sh" "FAILED: year-end join $CAM_NAME $ASTRO_YEAR" \
        "ffmpeg concat failed — the 12 movement montages are still intact" || true
    exit 1
fi

total_dur=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$output_file")
total_min=$(echo "scale=1; $total_dur / 60" | bc)
echo "Done: $output_file  (${total_min} min)"

# Sanity-check actual vs expected duration
dur_drift=$(echo "scale=3; $total_dur - $total_expected_dur" | bc | sed 's/^-//')
if awk "BEGIN{exit !($dur_drift > 2.0)}"; then
    echo "WARNING: output ${total_dur}s differs from expected ${total_expected_dur}s by ${dur_drift}s"
    "$SCRIPT_DIR/notify.sh" "WARNING: year-end duration drift $CAM_NAME $ASTRO_YEAR" \
        "Output ${total_dur}s vs expected ${total_expected_dur}s (drift ${dur_drift}s)" || true
fi

# ── Notify ────────────────────────────────────────────────────────────────────
"$SCRIPT_DIR/notify.sh" \
    "Four Seasons $ASTRO_YEAR complete [$CAM_NAME]" \
    "${CAM_NAME}-${ASTRO_YEAR}.mp4 — ${total_min} minutes  ($found movements) | $output_file" \
    || true