#!/bin/sh
# Compress MP4 page-bundle videos with FFmpeg before Hugo builds.
#
# Usage: sh scripts/compress-videos.sh [content-dir]
#
# Encoding choices:
#   H.264 CRF 28  — good web quality, ~60-80% smaller than camera/AI originals
#   preset slow   — best compression for a given CRF (fine in CI/Docker)
#   faststart     — moov atom moved to front for progressive streaming
#   aac 64k       — low-bitrate audio (videos are muted in-player by default)
#
# The script replaces each source file in-place only when the compressed
# output is actually smaller, so already-lean videos are left untouched.

set -e

CONTENT_DIR="${1:-content}"

find "$CONTENT_DIR" -name "*.mp4" | while IFS= read -r src; do
  tmp="${src%.mp4}.__tmp.mp4"

  echo "▶ $src"

  ffmpeg -i "$src" \
    -c:v libx264 \
    -crf 28 \
    -preset slow \
    -movflags +faststart \
    -c:a aac \
    -b:a 64k \
    -loglevel error \
    -y "$tmp" < /dev/null

  src_size=$(stat -c%s "$src" 2>/dev/null || stat -f%z "$src")
  tmp_size=$(stat -c%s "$tmp" 2>/dev/null || stat -f%z "$tmp")

  if [ "$tmp_size" -lt "$src_size" ]; then
    mv "$tmp" "$src"
    saved=$(( (src_size - tmp_size) / 1024 ))
    echo "  ✓ ${src_size} → ${tmp_size} bytes  (−${saved} KB)"
  else
    rm -f "$tmp"
    echo "  — already optimal, skipped"
  fi
done

echo "Done."
