#!/bin/bash
# montage-mvt.sh — compile one Vivaldi movement's daily clips into a montage.
#
# Duration matches the movement's music exactly.  Attribution is overlaid as a
# translucent bar across the top of the video for the first ATTR_DUR seconds
# (fade in/out) — no separate card appended, so year-end joining is a plain
# concat with no duplicate attribution concerns.
#
# Called automatically by 4-seasons.sh on the last day of each movement.
# Can also be run manually for a mid-season preview.
#
# On the last day of Autumn Mvt 3, automatically triggers year-end-join.sh.
#
# Music: "The Four Seasons" by Antonio Vivaldi
# Performed by John Harrison with the Wichita State University Chamber Players
# Source: Free Music Archive — freemusicarchive.org
# License: CC BY-SA 3.0

set -euo pipefail

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

# Args: [date] [camera-name]
# Camera name: second argument overrides conf (passed through from 4-seasons.sh).
CAM_NAME="${2:-$CAM_NAME}"

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

FADE_DUR=2.0   # video + audio fade in/out (seconds)
ATTR_DUR=6     # attribution overlay duration (seconds from start)
ATTR_FADE=1    # attribution fade in / fade out duration

# ── Season / movement info ────────────────────────────────────────────────────
DATE_ARG="${1:-}"
eval "$(python3 "$SCRIPT_DIR/season_info.py" ${DATE_ARG:+"$DATE_ARG"})"
# 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  (ref: ${DATE_ARG:-today})"

# ── Locate files ──────────────────────────────────────────────────────────────
video_dir="$MOVIES_DIR/$CAM_NAME/$ASTRO_YEAR/$SEASON/Mvt$MVT_NUM"
output_dir="$video_dir/montage"
mkdir -p "$output_dir"

music_file=$(find "$music_base_dir" -type f -iname "*${SEASON}*Mvt*${MVT_NUM}*" | sort | head -n 1)
if [ -z "$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)"

# ── Collect sorted daily clips ────────────────────────────────────────────────
mapfile -d '' daily_clips < <(find "$video_dir" -maxdepth 1 -name "*-final.mp4" -print0 | sort -z)
if [ "${#daily_clips[@]}" -eq 0 ]; then
    echo "ERROR: No *-final.mp4 clips in $video_dir"
    exit 1
fi
echo "Found ${#daily_clips[@]} daily clips"

# ── Source resolution ─────────────────────────────────────────────────────────
VIDEO_W=$(ffprobe -v error -select_streams v:0 -show_entries stream=width  -of csv=p=0 "${daily_clips[0]}")
VIDEO_H=$(ffprobe -v error -select_streams v:0 -show_entries stream=height -of csv=p=0 "${daily_clips[0]}")
echo "Source resolution: ${VIDEO_W}x${VIDEO_H}"

# ── Font detection ────────────────────────────────────────────────────────────
FONT=""; FONT_BOLD=""
if command -v fc-match &>/dev/null; then
    FONT=$(fc-match "DejaVu Sans:style=Regular" --format="%{file}" 2>/dev/null || true)
    FONT_BOLD=$(fc-match "DejaVu Sans:style=Bold"    --format="%{file}" 2>/dev/null || true)
fi
if [ -z "$FONT" ]; then
    for f in \
        /usr/share/fonts/truetype/dejavu/DejaVuSans.ttf \
        /usr/share/fonts/dejavu/DejaVuSans.ttf \
        /usr/share/fonts/TTF/DejaVuSans.ttf \
        /usr/share/fonts/truetype/freefont/FreeSans.ttf; do
        [ -f "$f" ] && { FONT="$f"; break; }
    done
fi
[ -z "$FONT_BOLD" ] && FONT_BOLD="$FONT"

# ── Temp files ────────────────────────────────────────────────────────────────
TMPFILES=()
cleanup() { rm -f "${TMPFILES[@]}" 2>/dev/null || true; }
trap cleanup EXIT

concat_list=$(mktemp --suffix=.txt); TMPFILES+=("$concat_list")
printf "file '%s'\n" "${daily_clips[@]}" > "$concat_list"

# ── Step 1: Concatenate + normalise resolution ────────────────────────────────
temp_concat=$(mktemp --suffix=.mp4); TMPFILES+=("$temp_concat")
echo "Step 1/3: concatenating ${#daily_clips[@]} clips..."
ffmpeg -loglevel warning \
    -f concat -safe 0 -i "$concat_list" \
    -vf "scale=${VIDEO_W}:${VIDEO_H}:force_original_aspect_ratio=decrease,\
pad=${VIDEO_W}:${VIDEO_H}:(ow-iw)/2:(oh-ih)/2,setsar=1" \
    -c:v libx264 -pix_fmt yuv420p -crf 26 -an \
    -y "$temp_concat"

# ── Step 2: Speed-adjust to match music duration exactly ──────────────────────
concat_dur=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$temp_concat")
speed_factor=$(echo "scale=6; $concat_dur / $music_duration" | bc)
echo "Step 2/3: speed $speed_factor  (raw=${concat_dur}s → music=${music_duration}s)"

temp_sped=$(mktemp --suffix=.mp4); TMPFILES+=("$temp_sped")
ffmpeg -loglevel warning \
    -i "$temp_concat" \
    -vf "setpts=PTS/$speed_factor" \
    -c:v libx264 -pix_fmt yuv420p -crf 26 -an \
    -t "$music_duration" -y "$temp_sped"
rm "$temp_concat"

# ── Step 3: Music + fades + attribution overlay ───────────────────────────────
# Attribution overlay: semi-transparent bar across the top for the first
# ATTR_DUR seconds, text fades in over ATTR_FADE s and out over ATTR_FADE s.
# alpha expression: 0→1 over first ATTR_FADE s, 1 in the middle, 1→0 over
# the last ATTR_FADE s before ATTR_DUR.
ATTR_FADE_END=$(echo "$ATTR_DUR - $ATTR_FADE" | bc)
ALPHA="if(lt(t,${ATTR_FADE}),t/${ATTR_FADE},if(gt(t,${ATTR_FADE_END}),(${ATTR_DUR}-t)/${ATTR_FADE},1))"
ENABLE="between(t,0,${ATTR_DUR})"

fade_out_start=$(echo "scale=3; $music_duration - $FADE_DUR" | bc)
echo "Step 3/3: music + fades + attribution overlay..."

# Build attribution drawtext filters (box=1 gives a per-line background).
# Colons inside text values are escaped as \: (\\: in bash double-quoted strings).
DT="drawtext=fontfile='${FONT_BOLD}'"
DT="${DT}:text='The Four Seasons \: Antonio Vivaldi'"
DT="${DT}:fontcolor=white:fontsize=h/22:x=(w-text_w)/2:y=h*0.012"
DT="${DT}:box=1:boxcolor=black@0.55:boxborderw=8"
DT="${DT}:alpha='${ALPHA}':enable='${ENABLE}'"

DT="${DT},drawtext=fontfile='${FONT}'"
DT="${DT}:text='John Harrison / Wichita State University Chamber Players'"
DT="${DT}:fontcolor=0xEEEEEE:fontsize=h/30:x=(w-text_w)/2:y=h*0.068"
DT="${DT}:box=1:boxcolor=black@0.55:boxborderw=6"
DT="${DT}:alpha='${ALPHA}':enable='${ENABLE}'"

DT="${DT},drawtext=fontfile='${FONT}'"
DT="${DT}:text='Free Music Archive \: freemusicarchive.org \: CC BY-SA 3.0'"
DT="${DT}:fontcolor=0xCCCCCC:fontsize=h/36:x=(w-text_w)/2:y=h*0.113"
DT="${DT}:box=1:boxcolor=black@0.55:boxborderw=5"
DT="${DT}:alpha='${ALPHA}':enable='${ENABLE}'"

output_file="$output_dir/${MVT_START}_${SEASON}_Mvt${MVT_NUM}-Montage.mp4"

ffmpeg -loglevel warning \
    -i "$temp_sped" -i "$music_file" \
    -filter_complex \
"[0:v]fade=t=in:st=0:d=${FADE_DUR},fade=t=out:st=${fade_out_start}:d=${FADE_DUR},${DT}[vout];\
[1:a]afade=t=in:st=0:d=${FADE_DUR},afade=t=out:st=${fade_out_start}:d=${FADE_DUR}[aout]" \
    -map "[vout]" -map "[aout]" \
    -c:v libx264 -pix_fmt yuv420p -c:a aac -b:a 192k \
    -t "$music_duration" -y "$output_file"
rm "$temp_sped"

echo "Done: $output_file"

# ── Notify ────────────────────────────────────────────────────────────────────
"$SCRIPT_DIR/notify.sh" \
    "Montage ready: $SEASON Mvt $MVT_NUM ($ASTRO_YEAR)" \
    "$(basename "$output_file") — ${music_duration}s" \
    || true   # notifications are best-effort

# ── Trigger year-end join on last Autumn movement ────────────────────────────
if [ "$SEASON" = "Autumn" ] && [ "$MVT_NUM" = "3" ]; then
    echo "Last movement of astronomical year $ASTRO_YEAR — triggering year-end join..."
    "$SCRIPT_DIR/year-end-join.sh" "$ASTRO_YEAR" "$CAM_NAME"
fi