#!/bin/bash

# ----------------------------
# Configurable Section
# ----------------------------
#
# 
# ----------------------------
# Default Values
# ----------------------------

SOURCE_BASE="$HOME"
NOTES_ROOT="notes/courses"
DEST_REL=""
SECTION_DIR=""
SHARE_REL=""
DEBUG=0

# ----------------------------
# Help Message
# ----------------------------

print_help() {
  cat <<EOF
Usage: $0 [options]

Options:
  --source-base PATH     Base directory where notes root begins (default: \$HOME)
  --notes-root PATH      Path from base to notes root (default: notes/courses)
  --section-dir PATH     Relative path under notes root to export (default: current directory)

  --dest-rel PATH        Relative path under the destination root to export
  
  --share-rel PATH       Relative path (from section-dir) to a shared _share directory (e.g. ../_share)
                         If provided, its contents will be copied to the DEST/_share folder (as a sibling)

  --debug                Print resolved paths and stop before exporting
  --help                 Show this help message


Behavior:
  - .org files are exported only if newer than corresponding .html files.
  - Shared assets from both --share-rel and section-local _share/ are merged into the destination.
  - Symlinks are preserved; .bak, .log, and dotfiles are excluded from rsync copies.

Examples:
  cd ~/notes/courses/business/music_money_makeover
  $0 --debug

  $0 \\
    --source-base ~/notes \\
    --notes-root notes/courses \\
    --section-dir business/music_money_makeover \\
    --share-rel ../_share
EOF
}

# ----------------------------
# Flag Parsing
# ----------------------------

while [[ "$#" -gt 0 ]]; do
  case "$1" in
    --source-base)
      SOURCE_BASE="$2"
      shift 2
      ;;
    --notes-root)
      NOTES_ROOT="$2"
      shift 2
      ;;
    --dest-rel)
      DEST_REL="$2"
      shift 2
      ;;
    --section-dir)
      SECTION_DIR="$2"
      shift 2
      ;;
    --share-rel)
      SHARE_REL="$2"
      shift 2
      ;;
    --debug)
      DEBUG=1
      shift
      ;;
    --help)
      print_help
      exit 0
      ;;
    *)
      echo "❌ Unknown option: $1"
      print_help
      exit 1
      ;;
  esac
done

# Auto-determine SECTION_DIR if not provided
if [ -z "$SECTION_DIR" ]; then
  full_path="$(cd "$(pwd)" && pwd)"
  base_path="$(cd "$SOURCE_BASE/$NOTES_ROOT" && pwd)"
  SECTION_DIR="${full_path#"$base_path"}"
fi


# ----------------------------
# Path Setup
# ----------------------------

SRC_DIR="$SOURCE_BASE/$NOTES_ROOT/$SECTION_DIR"
SHARE_DIR="$SRC_DIR/_share"
DATA_DIR="$SRC_DIR/_data"

# Detect OS and use appropriate destination base
if [[ "$OSTYPE" == "darwin"* ]]; then
    DEST_ROOT="/usr/local/var/www"
else
    DEST_ROOT="/var/www"
fi

if [ -n "$DEST_REL" ]; then
  DEST_DIR="$DEST_ROOT/$DEST_REL/$SECTION_DIR"
else
  DEST_DIR="$DEST_ROOT/$NOTES_ROOT/$SECTION_DIR"
fi

# ----------------------------
# Debug Output
# ----------------------------

echo "📁 SOURCE_BASE:  $SOURCE_BASE"
echo "📁 NOTES_ROOT:   $NOTES_ROOT"
echo "📁 SECTION_DIR:  $SECTION_DIR"
echo "📁 SRC_DIR:      $SRC_DIR"
echo "📁 DEST_DIR:     $DEST_DIR"
echo "📁 SHARE_DIR:    $SHARE_DIR"
echo "📁 DATA_DIR:     $DATA_DIR"

if [ "$DEBUG" -eq 1 ]; then
  echo "🛑 Debug mode enabled. Exiting before export."
  exit 0
fi


# ----------------------------
# Export .org to .html if changed
# ----------------------------

mkdir -p "$DEST_DIR"

find "$SRC_DIR" -name '*.org' ! -path "*/_share/*" | while read -r file; do

    rel_path="${file#$SRC_DIR/}"
    rel_dir="$(dirname "$rel_path")"
    dest_subdir="$DEST_DIR/$rel_dir"
    output_file="$dest_subdir/$(basename "${file%.org}.html")"

    if [ ! -f "$output_file" ] || [ "$file" -nt "$output_file" ]; then
        echo "Exporting $rel_path"
        mkdir -p "$dest_subdir"
        emacs "$file" --batch -l org --eval="(org-export-to-file 'html \"$output_file\")"
    else
        echo "Skipping $rel_path (no changes)"
    fi
done

# ----------------------------
# Copy shared assets (_share), preserving symlinks but skipping junk files
# ----------------------------
#
# --- Shared assets from --share-rel (e.g. ../_share → sibling)
if [ -n "$SHARE_REL" ]; then
    SHARE_SRC="$(cd "$SRC_DIR/$SHARE_REL" && pwd)"
    DEST_SHARE="$(dirname "$DEST_DIR")/_share"

    if [ -d "$SHARE_SRC" ]; then
        echo "📦 Copying shared assets from $SHARE_SRC to $DEST_SHARE"
        mkdir -p "$DEST_SHARE"
        rsync -a --update --keep-dirlinks \
          --exclude=".*" \
          --exclude="*.bak" \
          --exclude="*.log" \
          "$SHARE_SRC/" "$DEST_SHARE/"
    else
        echo "⚠️ Warning: resolved --share-rel '$SHARE_REL' to '$SHARE_SRC', but it does not exist"
    fi
fi

# --- Fallback to local _share (section-specific)
if [ -d "$SHARE_DIR" ]; then
    mkdir -p "$DEST_DIR/_share"
    rsync -a --update --keep-dirlinks \
      --exclude=".*" \
      --exclude="*.bak" \
      --exclude="*.log" \
      "$SHARE_DIR/" "$DEST_DIR/_share/"
fi

# ----------------------------
# Copy course-specific _data directory (if it exists)
# ----------------------------
if [ -d "$DATA_DIR" ]; then
    mkdir -p "$DEST_DIR/_data"
    rsync -a --update --keep-dirlinks \
      --exclude=".*" \
      --exclude="*.bak" \
      --exclude="*.log" \
      "$DATA_DIR/" "$DEST_DIR/_data/"
fi

echo "✅ Export complete for $SECTION_DIR → $DEST_DIR"