#!/usr/bin/env python3
import argparse
import json
import re
from pathlib import Path
from zipfile import ZipFile, ZIP_DEFLATED


def fill_docx_template(template_path: str, output_path: str, data: dict) -> int:
    with ZipFile(template_path, 'r') as zin:
        xml = zin.read('word/document.xml').decode('utf-8', 'ignore')

    replaced = 0
    for key, value in data.items():
        ph = '{{' + str(key) + '}}'
        val = str(value)
        count = xml.count(ph)
        if count:
            replaced += count
            xml = xml.replace(ph, val)

    # warn on unresolved placeholders
    unresolved = sorted(set(re.findall(r'\{\{[^{}]+\}\}', xml)))

    with ZipFile(template_path, 'r') as zin, ZipFile(output_path, 'w', ZIP_DEFLATED) as zout:
        for item in zin.infolist():
            content = zin.read(item.filename)
            if item.filename == 'word/document.xml':
                content = xml.encode('utf-8')
            zout.writestr(item, content)

    print(f'written: {output_path}')
    print(f'replaced: {replaced}')
    if unresolved:
        print('unresolved_placeholders:')
        for u in unresolved:
            print(f' - {u}')
    else:
        print('unresolved_placeholders: none')
    return 0


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument('--template', required=True, help='Path to .docx template with {{PLACEHOLDER}}')
    ap.add_argument('--data', required=True, help='Path to JSON map: {"PLACEHOLDER":"value"}')
    ap.add_argument('--out', required=True, help='Output .docx path')
    args = ap.parse_args()

    template = Path(args.template)
    data_path = Path(args.data)
    out = Path(args.out)

    with open(data_path, 'r', encoding='utf-8') as f:
        data = json.load(f)

    out.parent.mkdir(parents=True, exist_ok=True)
    raise SystemExit(fill_docx_template(str(template), str(out), data))


if __name__ == '__main__':
    main()