#!/usr/bin/env python3
"""Refresh the BUILD file of SPDX license_kinds with new ones from licenses.json.

Usage:
  wget https://github.com/spdx/license-list-data/raw/master/json/licenses.json
  LC_ALL="en_US.UTF-8" admin/refresh_spdx/add_licenses.py
  git diff
  git commit
"""

import json
import os
from string import Template
import re
import sys

def load_json(path: str):
  """Loads a JSON file and returns the data.

  Args:
    path: (str) a file path.
  Returns:
    (dict) the parsed data.
  """
  with open(path, 'r') as fp:
    ret = json.load(fp)
  return ret


def parse_build_file(text: str):
  """Parse a BUILD file of license declaration.

  Parses a build file and returns all the text that
  is not licenese_kind declarations and a map of
  license kind names to the text which declared them

  license_kind(
    name = "0BSD",
    conditions = [],
    url = "https://spdx.org/licenses/0BSD.html",
  )

  Returns:
    preamble: str 
    targets: map<str, str>
  """

  target_start = re.compile(r'^([a-zA-Z0-9_]+)\(')  # ) to fix autoindent
  name_match = re.compile(r'^ *name *= *"([^"]*)"')

  targets = {}
  preamble = []
  collecting_rule = None

  for line in text.split('\n'):
    if collecting_rule:
      collecting_rule.append(line)
      if line.startswith(')'):
        assert cur_name
        targets[cur_name] = '\n'.join(collecting_rule)
        # print(cur_name, "=====", targets[cur_name])
        collecting_rule = None
        cur_name = None
      else:
        m = name_match.match(line)
        if m:
          cur_name = m.group(1)
      continue

    # not collecting a rule
    m = target_start.match(line)
    if m:
      cur_rule = m.group(1)
      if cur_rule == 'license_kind':
        collecting_rule = [line]
        continue

    if line or preamble[-1]:
      preamble.append(line)

  return '\n'.join(preamble), targets


# Sample JSON formate license declaration.
"""
{
  "licenseListVersion": "3.8-57-gca4f142",
  "licenses": [
    {
      "reference": "./0BSD.html",
      "isDeprecatedLicenseId": false,
      "detailsUrl": "http://spdx.org/licenses/0BSD.json",
      "referenceNumber": "232",
      "name": "BSD Zero Clause License",
      "licenseId": "0BSD",
      "seeAlso": [
        "http://landley.net/toybox/license.html"
      ],
      "isOsiApproved": true
    },
"""


def insert_new(already_declared, licenses):
  template = Template((
      'license_kind(\n'
      '    name = "${licenseId}",\n'
      '    conditions = [],\n'
      '    url = "https://spdx.org/licenses/${licenseId}.html",\n'
      ')'))

  for license in licenses:
    id = license['licenseId']
    old = already_declared.get(id)
    if not old:
      print('Adding:', id)
      already_declared[id] = template.substitute(license)


def update_spdx_build():
  """Update //licenses/spdx/BUILD with new license kinds."""

  license_json = load_json('licenses.json')

  # Find workspace root
  build_path = 'licenses/spdx/BUILD'
  found_spdx_build = False
  for i in range(5):  # Simple regression failure limiter
    if os.access('WORKSPACE', os.R_OK) and os.access(build_path, os.R_OK):
      found_spdx_build = True
      break
    os.chdir('..')
  if not found_spdx_build:
    print('Could not find', build_path)
    return 1

  with open(build_path, 'r') as fp:
    current_file_content = fp.read()

  preamble, kinds = parse_build_file(current_file_content)
  insert_new(kinds, license_json['licenses'])
  with open(build_path, 'w') as fp:
    fp.write(preamble)
    for license in sorted(kinds.keys(), key=lambda x: x.lower()):
      fp.write('\n')
      fp.write(kinds[license])
      fp.write('\n')


def main():
  lc_all = os.environ.get('LC_ALL')
  if lc_all != 'en_US.UTF-8':
    print('Your environment settings will reorder the file badly.')
    print('Please rerun as:')
    print('  LC_ALL="en_US.UTF-8"', ' '.join(sys.argv))
    sys.exit(1)

  update_spdx_build()


if __name__ == '__main__':
  main()