#!/usr/bin/env python3
#
# Copyright 2017 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from __future__ import print_function
import argparse
import glob
import os
from os import path
import shutil
import sys

from nototools import unicode_data

"""Create aliases in target directory.

In addition to links/copies named with aliased sequences, this can also
create canonically named aliases/copies, if requested."""


DATA_ROOT = path.dirname(path.abspath(__file__))

def str_to_seq(seq_str):
  res = [int(s, 16) for s in seq_str.split('_')]
  if 0xfe0f in res:
    print('0xfe0f in file name: %s' % seq_str)
    res = [x for x in res if x != 0xfe0f]
  return tuple(res)


def seq_to_str(seq):
  return '_'.join('%04x' % cp for cp in seq)


def read_default_unknown_flag_aliases():
  unknown_flag_path = path.join(DATA_ROOT, 'unknown_flag_aliases.txt')
  return read_emoji_aliases(unknown_flag_path)


def read_default_emoji_aliases():
  alias_path = path.join(DATA_ROOT, 'emoji_aliases.txt')
  return read_emoji_aliases(alias_path)


def read_emoji_aliases(filename):
  result = {}

  with open(filename, 'r') as f:
    for line in f:
      ix = line.find('#')
      if (ix > -1):
        line = line[:ix]
      line = line.strip()
      if not line:
        continue
      als, trg = (s.strip() for s in line.split(';'))
      try:
        als_seq = tuple([int(x, 16) for x in als.split('_')])
        trg_seq = tuple([int(x, 16) for x in trg.split('_')])
      except:
        print('cannot process alias %s -> %s' % (als, trg))
        continue
      result[als_seq] = trg_seq
  return result


def add_aliases(
    srcdir, dstdir, aliasfile, prefix, ext, replace=False, copy=False,
    canonical_names=False, dry_run=False):
  """Use aliasfile to create aliases of files in srcdir matching prefix/ext in
  dstdir.  If dstdir is null, use srcdir as dstdir.  If replace is false
  and a file already exists in dstdir, report and do nothing.  If copy is false
  create a symlink, else create a copy.

  If canonical_names is true, check all source files and generate aliases/copies
  using the canonical name if different from the existing name.

  If dry_run is true, report what would be done.  Dstdir will be created if
  necessary, even if dry_run is true."""

  if not path.isdir(srcdir):
    print('%s is not a directory' % srcdir, file=sys.stderr)
    return

  if not dstdir:
    dstdir = srcdir
  elif not path.isdir(dstdir):
    os.makedirs(dstdir)

  prefix_len = len(prefix)
  suffix_len = len(ext) + 1
  filenames = [path.basename(f)
               for f in glob.glob(path.join(srcdir, '%s*.%s' % (prefix, ext)))]
  seq_to_file = {
      str_to_seq(name[prefix_len:-suffix_len]) : name
      for name in filenames}

  aliases = read_emoji_aliases(aliasfile)
  aliases_to_create = {}
  aliases_to_replace = []
  alias_exists = False

  def check_alias_seq(seq):
    alias_str = seq_to_str(seq)
    alias_name = '%s%s.%s' % (prefix, alias_str, ext)
    alias_path = path.join(dstdir, alias_name)
    if path.exists(alias_path):
      if replace:
        aliases_to_replace.append(alias_name)
      else:
        print('alias %s exists' % alias_str, file=sys.stderr)
        alias_exists = True
        return None
    return alias_name

  canonical_to_file = {}
  for als, trg in sorted(aliases.items()):
    if trg not in seq_to_file:
      print('target %s for %s does not exist' % (
          seq_to_str(trg), seq_to_str(als)), file=sys.stderr)
      continue
    alias_name = check_alias_seq(als)
    if alias_name:
      target_file = seq_to_file[trg]
      aliases_to_create[alias_name] = target_file
      if canonical_names:
        canonical_seq = unicode_data.get_canonical_emoji_sequence(als)
        if canonical_seq and canonical_seq != als:
          canonical_alias_name = check_alias_seq(canonical_seq)
          if canonical_alias_name:
            canonical_to_file[canonical_alias_name] = target_file

  if canonical_names:
    print('adding %d canonical aliases' % len(canonical_to_file))
    for seq, f in seq_to_file.iteritems():
      canonical_seq = unicode_data.get_canonical_emoji_sequence(seq)
      if canonical_seq and canonical_seq != seq:
        alias_name = check_alias_seq(canonical_seq)
        if alias_name:
          canonical_to_file[alias_name] = f

    print('adding %d total canonical sequences' % len(canonical_to_file))
    aliases_to_create.update(canonical_to_file)

  if replace:
    if not dry_run:
      for k in sorted(aliases_to_replace):
        os.remove(path.join(dstdir, k))
    print('replacing %d files' % len(aliases_to_replace))
  elif alias_exists:
    print('aborting, aliases exist.', file=sys.stderr)
    return

  for k, v in sorted(aliases_to_create.items()):
    if dry_run:
      msg = 'replace ' if k in aliases_to_replace else ''
      print('%s%s -> %s' % (msg, k, v))
    else:
      try:
        if copy:
          shutil.copy2(path.join(srcdir, v), path.join(dstdir, k))
        else:
          # fix this to create relative symlinks
          if srcdir == dstdir:
            os.symlink(v, path.join(dstdir, k))
          else:
            raise Exception('can\'t create cross-directory symlinks yet')
      except Exception as e:
        print('failed to create %s -> %s' % (k, v), file=sys.stderr)
        raise Exception('oops, ' + str(e))
  print('created %d %s' % (
      len(aliases_to_create), 'copies' if copy else 'symlinks'))


def main():
  parser = argparse.ArgumentParser()
  parser.add_argument(
      '-s', '--srcdir', help='directory containing files to alias',
      required=True, metavar='dir')
  parser.add_argument(
      '-d', '--dstdir', help='directory to write aliases, default srcdir',
      metavar='dir')
  parser.add_argument(
      '-a', '--aliasfile', help='alias file (default emoji_aliases.txt)',
      metavar='file', default='emoji_aliases.txt')
  parser.add_argument(
      '-p', '--prefix', help='file name prefix (default emoji_u)',
      metavar='pfx', default='emoji_u')
  parser.add_argument(
      '-e', '--ext', help='file name extension (default png)',
      choices=['ai', 'png', 'svg'], default='png')
  parser.add_argument(
      '-r', '--replace', help='replace existing files/aliases',
      action='store_true')
  parser.add_argument(
      '-c', '--copy', help='create a copy of the file, not a symlink',
      action='store_true')
  parser.add_argument(
      '--canonical_names', help='include extra copies with canonical names '
      '(including fe0f emoji presentation character)', action='store_true');
  parser.add_argument(
      '-n', '--dry_run', help='print out aliases to create only',
      action='store_true')
  args = parser.parse_args()

  add_aliases(
      args.srcdir, args.dstdir, args.aliasfile, args.prefix, args.ext,
      args.replace, args.copy, args.canonical_names, args.dry_run)


if __name__ == '__main__':
  main()