#!/bin/bash
set -e

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
FRONTEND_DIR="$(dirname "$SCRIPT_DIR")"
PROJECT_DIR="$(dirname "$FRONTEND_DIR")"
OUTPUT_DIR="$FRONTEND_DIR/demo-output"

mkdir -p "$OUTPUT_DIR"

echo "=== Step 1: Generate TTS audio ==="
source "$PROJECT_DIR/.venv/bin/activate"
python3 "$SCRIPT_DIR/generate-tts.py" "$OUTPUT_DIR"

echo "=== Step 2: Record Cypress demo ==="
cd "$FRONTEND_DIR"
npx cypress run --spec "cypress/e2e/demo-walkthrough.cy.js" || true

# Find the recorded video
VIDEO=$(find cypress/videos -name "demo-walkthrough*" -type f 2>/dev/null | head -1)
if [ -z "$VIDEO" ]; then
  echo "ERROR: No video found in cypress/videos/"
  exit 1
fi
echo "Found video: $VIDEO"
cp "$VIDEO" "$OUTPUT_DIR/raw-screen.mp4"

echo "=== Step 3: Combine video + audio + subtitles ==="

# Get video and audio durations
VIDEO_DUR=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$OUTPUT_DIR/raw-screen.mp4" | cut -d. -f1)
AUDIO_DUR=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$OUTPUT_DIR/narration.mp3" | cut -d. -f1)
echo "Video: ${VIDEO_DUR}s, Audio: ${AUDIO_DUR}s"

# Use the longer duration, speed-adjust video if needed
if [ "$VIDEO_DUR" -gt "$AUDIO_DUR" ]; then
  # Speed up video to match audio length
  SPEED=$(python3 -c "print(round($VIDEO_DUR / $AUDIO_DUR, 3))")
  echo "Speeding up video by ${SPEED}x"
  ffmpeg -y -i "$OUTPUT_DIR/raw-screen.mp4" \
    -filter:v "setpts=PTS/${SPEED}" \
    -an "$OUTPUT_DIR/adjusted-screen.mp4" 2>/dev/null
elif [ "$AUDIO_DUR" -gt "$VIDEO_DUR" ]; then
  # Slow down video
  SPEED=$(python3 -c "print(round($VIDEO_DUR / $AUDIO_DUR, 3))")
  echo "Slowing video to ${SPEED}x"
  ffmpeg -y -i "$OUTPUT_DIR/raw-screen.mp4" \
    -filter:v "setpts=PTS/${SPEED}" \
    -an "$OUTPUT_DIR/adjusted-screen.mp4" 2>/dev/null
else
  cp "$OUTPUT_DIR/raw-screen.mp4" "$OUTPUT_DIR/adjusted-screen.mp4"
fi

# Combine: video + audio + burned-in subtitles
ffmpeg -y \
  -i "$OUTPUT_DIR/adjusted-screen.mp4" \
  -i "$OUTPUT_DIR/narration.mp3" \
  -vf "subtitles=$SCRIPT_DIR/demo-subtitles.srt:force_style='FontSize=20,FontName=Noto Sans CJK SC,PrimaryColour=&H00FFFFFF,OutlineColour=&H00000000,Outline=2,Shadow=1,MarginV=30'" \
  -c:v libx264 -preset fast -crf 23 \
  -c:a aac -b:a 128k \
  -shortest \
  "$OUTPUT_DIR/demo-final.mp4" 2>/dev/null

echo ""
echo "=== Done! ==="
echo "Output: $OUTPUT_DIR/demo-final.mp4"
ls -lh "$OUTPUT_DIR/demo-final.mp4"