#!/usr/bin/env bash
set -euo pipefail

REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
OUTPUT_DIR="$REPO_ROOT/slides"

# Find all markdown files with marp: true frontmatter
SLIDES=()
while IFS= read -r f; do
  SLIDES+=("$f")
done < <(grep -rl "^marp: true" "$REPO_ROOT/docs" --include="*.md" --exclude-dir=superpowers 2>/dev/null || true)

if [ ${#SLIDES[@]} -eq 0 ]; then
  echo "No marp presentations found in docs/."
  exit 0
fi

echo "Found ${#SLIDES[@]} presentation(s):"
printf '  %s\n' "${SLIDES[@]}"

# Create temp output directory for Docker
TEMP_OUTPUT=$(mktemp -d)
chmod 777 "$TEMP_OUTPUT"
trap "rm -rf '$TEMP_OUTPUT'" EXIT

if command -v marp &>/dev/null; then
  marp --html --output "$OUTPUT_DIR/" "${SLIDES[@]}"
else
  echo "marp not found locally — using Docker (marpteam/marp-cli)..."
  # Process each slide individually in Docker
  for slide in "${SLIDES[@]}"; do
    REL_SLIDE="${slide#${REPO_ROOT}/}"
    BASENAME=$(basename "${slide%.*}")
    docker run --rm \
      -v "$REPO_ROOT":/home/marp/app:ro \
      -v "$TEMP_OUTPUT":/home/marp/output \
      marpteam/marp-cli --html --output "/home/marp/output/${BASENAME}.html" "$REL_SLIDE"
  done
fi

# Ensure output directory exists
mkdir -p "$OUTPUT_DIR"

# Copy generated HTML files to final output directory
cp "$TEMP_OUTPUT"/*.html "$OUTPUT_DIR/" 2>/dev/null || true

# Inject mermaid.js into any HTML that contains mermaid code blocks.
# Marp emits fenced mermaid blocks as <pre><code class="language-mermaid">.
# The script finds those elements, replaces them with <div class="mermaid">,
# then loads and runs mermaid.js from CDN.
inject_mermaid() {
  local html_file="$1"
  python3 - "$html_file" << 'PYEOF'
import sys

path = sys.argv[1]
snippet = """\
<script type="module">
import mermaid from 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs';
document.querySelectorAll('code.language-mermaid').forEach(el => {
  const div = document.createElement('div');
  div.className = 'mermaid';
  div.textContent = el.textContent;
  el.parentElement.replaceWith(div);
});
mermaid.initialize({ startOnLoad: false, theme: 'dark' });
await mermaid.run();
</script>"""

with open(path, encoding='utf-8') as f:
    content = f.read()
new_content = content.replace('</body>', snippet + '\n</body>', 1)
if new_content == content:
    print(f"Warning: </body> not found in {path}", file=sys.stderr)
    sys.exit(1)
with open(path, 'w', encoding='utf-8') as f:
    f.write(new_content)
PYEOF
}

if command -v python3 &>/dev/null; then
  for html_file in "$OUTPUT_DIR"/*.html; do
    [ -f "$html_file" ] || continue
    if grep -q 'class="language-mermaid"' "$html_file"; then
      inject_mermaid "$html_file"
      echo "  Injected mermaid.js into $(basename "$html_file")"
    fi
  done
else
  echo "Warning: python3 not found — skipping mermaid injection"
fi

echo "Done — slides in $OUTPUT_DIR/"