#!/usr/bin/env bash
# epubmake -- full EPUB creation pipeline with metadata + validation
set -euo pipefail

usage() {
    echo "Usage: epubmake <input.md> [--title TITLE] [--author AUTHOR] [--cover cover.jpg]"
    exit 1
}

[ $# -lt 1 ] && usage

input="$1"; shift
title="" author="" cover="" output=""

while [ $# -gt 0 ]; do
    case "$1" in
        --title)  title="$2"; shift 2 ;;
        --author) author="$2"; shift 2 ;;
        --cover)  cover="$2"; shift 2 ;;
        --output|-o) output="$2"; shift 2 ;;
        *) echo "Unknown option: $1"; usage ;;
    esac
done

[ -z "$output" ] && output="${input%.md}.epub"

args=(-t epub3 --toc --toc-depth=2)
[ -n "$title" ] && args+=(--metadata "title=$title")
[ -n "$author" ] && args+=(--metadata "author=$author")
[ -n "$cover" ] && args+=(--epub-cover-image="$cover")

echo "Building EPUB: $output"

# Handle single file or directory of chapters
if [ -d "$input" ]; then
    chapters=$(ls "$input"/*.md 2>/dev/null | sort -V)
    [ -z "$chapters" ] && { echo "No .md files in $input"; exit 1; }
    pandoc $chapters "${args[@]}" -o "$output"
else
    pandoc "$input" "${args[@]}" -o "$output"
fi

echo "Created: $output ($(du -h "$output" | cut -f1))"

# Validate if epubcheck is available
if command -v epubcheck &>/dev/null; then
    echo ""
    echo "Validating..."
    epubcheck "$output" 2>&1 | tail -5
elif command -v python3 -c "import epubcheck" &>/dev/null 2>&1; then
    python3 -c "from epubcheck import EpubCheck; r = EpubCheck('$output'); print('Valid' if r.valid else 'INVALID')"
else
    echo "(epubcheck not installed, skipping validation)"
fi