#!/usr/bin/env python3
#
# Copyright 2014 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import argparse
import collections
from datetime import date
import re
from string import Template
import sys
import textwrap
import zipfile

from util import build_utils  # pylint: disable=unused-import
from util import java_cpp_utils
import action_helpers  # build_utils adds //build to sys.path.
import zip_helpers


# List of C++ types that are compatible with the Java code generated by this
# script.
#
# This script can parse .idl files however, at present it ignores special
# rules such as [cpp_enum_prefix_override="ax_attr"].
ENUM_FIXED_TYPE_ALLOWLIST = [
    'char', 'unsigned char', 'short', 'unsigned short', 'int', 'int8_t',
    'int16_t', 'int32_t', 'uint8_t', 'uint16_t'
]


class EnumDefinition:

  def __init__(self,
               original_enum_name=None,
               class_name_override=None,
               enum_package=None,
               entries=None,
               comments=None,
               fixed_type=None,
               is_flag=False):
    """Represents a C++ enum that must be converted to java.

    Args:
      original_enum_name: The name of the enum itself, without its package.
        If every entry starts with this value, this prefix is removed.
      class_name_override: the name for the enum in java.
        If None, the original enum name is used.
      enum_package: The java package in which this enum must be defined
      entries: A list of pairs. Each pair contains an enum entry, followed by
        either None or the value of this entry. The definition could be, for
        example, an integer, an expression `2 << 5`, or another enun entry.
      comments: A list of pairs. Each pair contains an entry and a comment
        associated to this entry.
      fixed_type: The type encoding this enum. Should belong to
        `ENUM_FIXED_TYPE_ALLOWLIST`.
      is_flag: Whether this value is used as a boolean flag whose entries can
        be xored together.
    """
    self.original_enum_name = original_enum_name
    self.class_name_override = class_name_override
    self.enum_package = enum_package
    self.entries = collections.OrderedDict(entries or [])
    self.comments = collections.OrderedDict(comments or [])
    self.prefix_to_strip = None
    self.fixed_type = fixed_type
    self.is_flag = is_flag

  def AppendEntry(self, key, value):
    if key in self.entries:
      raise Exception('Multiple definitions of key %s found.' % key)
    self.entries[key] = value

  def AppendEntryComment(self, key, value):
    if key in self.comments:
      raise Exception('Multiple definitions of key %s found.' % key)
    self.comments[key] = value

  @property
  def class_name(self):
    return self.class_name_override or self.original_enum_name

  def Finalize(self):
    self._Validate()
    self._AssignEntryIndices()
    self._StripPrefix()
    self._NormalizeNames()

  def _Validate(self):
    assert self.class_name
    assert self.enum_package
    assert self.entries
    if self.fixed_type and self.fixed_type not in ENUM_FIXED_TYPE_ALLOWLIST:
      raise Exception('Fixed type %s for enum %s not in allowlist.' %
                      (self.fixed_type, self.class_name))

  def _AssignEntryIndices(self):
    # Enums, if given no value, are given the value of the previous enum + 1.
    if not all(self.entries.values()):
      prev_enum_value = -1
      for key, value in self.entries.items():
        if not value:
          self.entries[key] = prev_enum_value + 1
        elif value in self.entries:
          self.entries[key] = self.entries[value]
        else:
          try:
            self.entries[key] = int(value)
          except ValueError as e:
            raise Exception('Could not interpret integer from enum value "%s" '
                            'for key %s.' % (value, key)) from e
        prev_enum_value = self.entries[key]


  def _StripPrefix(self):
    prefix_to_strip = self.prefix_to_strip
    if not prefix_to_strip:
      shout_case = self.original_enum_name
      shout_case = re.sub('(?!^)([A-Z]+)', r'_\1', shout_case).upper()
      shout_case += '_'

      prefixes = [shout_case, self.original_enum_name,
                  'k' + self.original_enum_name]

      # "kMaxValue" is a special enum entry representing the last value of an
      # histogram enum. It is not expected to have prefix even when other values
      # have a prefix.
      standard_keys = [key for key in self.entries.keys() if key != "kMaxValue"]

      for prefix in prefixes:
        if all(w.startswith(prefix) for w in standard_keys):
          prefix_to_strip = prefix
          break
      else:
        prefix_to_strip = ''

    def StripEntries(entries):
      ret = collections.OrderedDict()
      for k, v in entries.items():
        stripped_key = k.replace(prefix_to_strip, '', 1)
        if isinstance(v, str):
          stripped_value = v.replace(prefix_to_strip, '')
        else:
          stripped_value = v
        ret[stripped_key] = stripped_value

      return ret

    self.entries = StripEntries(self.entries)
    self.comments = StripEntries(self.comments)

  def _NormalizeNames(self):
    self.entries = _TransformKeys(self.entries, java_cpp_utils.KCamelToShouty)
    self.comments = _TransformKeys(self.comments, java_cpp_utils.KCamelToShouty)


def _TransformKeys(d, func):
  """Normalize keys in |d| and update references to old keys in |d| values."""
  keys_map = {k: func(k) for k in d}
  ret = collections.OrderedDict()
  for k, v in d.items():
    # Need to transform values as well when the entry value was explicitly set
    # (since it could contain references to other enum entry values).
    if isinstance(v, str):
      # First check if a full replacement is available. This avoids issues when
      # one key is a substring of another.
      if v in d:
        v = keys_map[v]
      else:
        for old_key, new_key in keys_map.items():
          v = v.replace(old_key, new_key)
    ret[keys_map[k]] = v
  return ret


class DirectiveSet:
  class_name_override_key = 'CLASS_NAME_OVERRIDE'
  enum_package_key = 'ENUM_PACKAGE'
  prefix_to_strip_key = 'PREFIX_TO_STRIP'
  is_flag = 'IS_FLAG'

  known_keys = [
      class_name_override_key, enum_package_key, prefix_to_strip_key, is_flag
  ]

  def __init__(self):
    self._directives = {}

  def Update(self, key, value):
    if key not in DirectiveSet.known_keys:
      raise Exception("Unknown directive: " + key)
    self._directives[key] = value

  @property
  def empty(self):
    return len(self._directives) == 0

  def UpdateDefinition(self, definition):
    definition.class_name_override = self._directives.get(
        DirectiveSet.class_name_override_key, '')
    definition.enum_package = self._directives.get(
        DirectiveSet.enum_package_key)
    definition.prefix_to_strip = self._directives.get(
        DirectiveSet.prefix_to_strip_key)
    definition.is_flag = self._directives.get(
        DirectiveSet.is_flag) not in [None, 'false', '0']


class HeaderParser:
  single_line_comment_re = re.compile(r'\s*//\s*([^\n]*)')
  multi_line_comment_start_re = re.compile(r'\s*/\*')
  enum_line_re = re.compile(r'^\s*(\w+)(\s*\=\s*([^,\n]+))?,?')
  enum_end_re = re.compile(r'^\s*}\s*;\.*$')
  # Note: For now we only support a very specific `#if` statement to prevent the
  # possibility of miscalculating whether lines should be ignored when building
  # for Android.
  if_buildflag_re = re.compile(
      r'^#if BUILDFLAG\((\w+)\)(?: \|\| BUILDFLAG\((\w+)\))*$')
  if_buildflag_end_re = re.compile(r'^#endif.*$')
  generator_error_re = re.compile(r'^\s*//\s+GENERATED_JAVA_(\w+)\s*:\s*$')
  generator_directive_re = re.compile(
      r'^\s*//\s+GENERATED_JAVA_(\w+)\s*:\s*([\.\w]+)$')
  multi_line_generator_directive_start_re = re.compile(
      r'^\s*//\s+GENERATED_JAVA_(\w+)\s*:\s*\(([\.\w]*)$')
  multi_line_directive_continuation_re = re.compile(r'^\s*//\s+([\.\w]+)$')
  multi_line_directive_end_re = re.compile(r'^\s*//\s+([\.\w]*)\)$')

  optional_class_or_struct_re = r'(class|struct)?'
  enum_name_re = r'(\w+)'
  optional_fixed_type_re = r'(\:\s*(\w+\s*\w+?))?'
  enum_start_re = re.compile(r'^\s*(?:\[cpp.*\])?\s*enum\s+' +
                             optional_class_or_struct_re + r'\s*' +
                             enum_name_re + r'\s*' + optional_fixed_type_re +
                             r'\s*{\s*')
  enum_single_line_re = re.compile(
      r'^\s*(?:\[cpp.*\])?\s*enum.*{(?P<enum_entries>.*)}.*$')

  def __init__(self, lines, path=''):
    self._lines = lines
    self._path = path
    self._enum_definitions = []
    self._in_enum = False
    # Indicates whether an #if block was encountered on a previous line (until
    # an #endif block was seen). When nonzero, `_in_buildflag_android` indicates
    # whether the blocks were `#if BUILDFLAG(IS_ANDROID)` or not.
    # Note: Currently only statements like `#if BUILDFLAG(IS_<PLATFORM>)` are
    # supported.
    self._in_preprocessor_block = 0
    self._in_buildflag_android = []
    self._current_definition = None
    self._current_comments = []
    self._generator_directives = DirectiveSet()
    self._multi_line_generator_directive = None
    self._current_enum_entry = ''

  def _ShouldIgnoreLine(self):
    return self._in_preprocessor_block and not all(self._in_buildflag_android)

  def _ApplyGeneratorDirectives(self):
    self._generator_directives.UpdateDefinition(self._current_definition)
    self._generator_directives = DirectiveSet()

  def ParseDefinitions(self):
    for line in self._lines:
      self._ParseLine(line)
    return self._enum_definitions

  def _ParseLine(self, line):
    if HeaderParser.if_buildflag_re.match(line):
      self._in_preprocessor_block += 1
      self._in_buildflag_android.append('BUILDFLAG(IS_ANDROID)' in line)
      return
    if self._in_preprocessor_block and HeaderParser.if_buildflag_end_re.match(
        line):
      self._in_preprocessor_block -= 1
      self._in_buildflag_android.pop()
      return

    if self._ShouldIgnoreLine():
      return

    if self._multi_line_generator_directive:
      self._ParseMultiLineDirectiveLine(line)
      return

    if not self._in_enum:
      self._ParseRegularLine(line)
      return

    self._ParseEnumLine(line)

  def _ParseEnumLine(self, line):
    if HeaderParser.multi_line_comment_start_re.match(line):
      raise Exception('Multi-line comments in enums are not supported in ' +
                      self._path)

    enum_comment = HeaderParser.single_line_comment_re.match(line)
    if enum_comment:
      comment = enum_comment.groups()[0]
      if comment:
        self._current_comments.append(comment)
    elif HeaderParser.enum_end_re.match(line):
      self._FinalizeCurrentEnumDefinition()
    else:
      self._AddToCurrentEnumEntry(line)
      if ',' in line:
        self._ParseCurrentEnumEntry()

  def _ParseSingleLineEnum(self, line):
    for entry in line.split(','):
      self._AddToCurrentEnumEntry(entry)
      self._ParseCurrentEnumEntry()

    self._FinalizeCurrentEnumDefinition()

  def _ParseCurrentEnumEntry(self):
    if not self._current_enum_entry:
      return

    enum_entry = HeaderParser.enum_line_re.match(self._current_enum_entry)
    if not enum_entry:
      raise Exception('Unexpected error while attempting to parse %s as enum '
                      'entry.' % self._current_enum_entry)

    enum_key = enum_entry.groups()[0]
    enum_value = enum_entry.groups()[2]
    self._current_definition.AppendEntry(enum_key, enum_value)
    if self._current_comments:
      self._current_definition.AppendEntryComment(
          enum_key, ' '.join(self._current_comments))
      self._current_comments = []
    self._current_enum_entry = ''

  def _AddToCurrentEnumEntry(self, line):
    self._current_enum_entry += ' ' + line.strip()

  def _FinalizeCurrentEnumDefinition(self):
    if self._current_enum_entry:
      self._ParseCurrentEnumEntry()
    self._ApplyGeneratorDirectives()
    self._current_definition.Finalize()
    self._enum_definitions.append(self._current_definition)
    self._current_definition = None
    self._in_enum = False

  def _ParseMultiLineDirectiveLine(self, line):
    multi_line_directive_continuation = (
        HeaderParser.multi_line_directive_continuation_re.match(line))
    multi_line_directive_end = (
        HeaderParser.multi_line_directive_end_re.match(line))

    if multi_line_directive_continuation:
      value_cont = multi_line_directive_continuation.groups()[0]
      self._multi_line_generator_directive[1].append(value_cont)
    elif multi_line_directive_end:
      directive_name = self._multi_line_generator_directive[0]
      directive_value = "".join(self._multi_line_generator_directive[1])
      directive_value += multi_line_directive_end.groups()[0]
      self._multi_line_generator_directive = None
      self._generator_directives.Update(directive_name, directive_value)
    else:
      raise Exception('Malformed multi-line directive declaration in ' +
                      self._path)

  def _ParseRegularLine(self, line):
    enum_start = HeaderParser.enum_start_re.match(line)
    generator_directive_error = HeaderParser.generator_error_re.match(line)
    generator_directive = HeaderParser.generator_directive_re.match(line)
    multi_line_generator_directive_start = (
        HeaderParser.multi_line_generator_directive_start_re.match(line))
    single_line_enum = HeaderParser.enum_single_line_re.match(line)

    if generator_directive_error:
      raise Exception('Malformed directive declaration in ' + self._path +
                      '. Use () for multi-line directives. E.g.\n' +
                      '// GENERATED_JAVA_ENUM_PACKAGE: (\n' +
                      '//   foo.package)')
    if generator_directive:
      directive_name = generator_directive.groups()[0]
      directive_value = generator_directive.groups()[1]
      self._generator_directives.Update(directive_name, directive_value)
    elif multi_line_generator_directive_start:
      directive_name = multi_line_generator_directive_start.groups()[0]
      directive_value = multi_line_generator_directive_start.groups()[1]
      self._multi_line_generator_directive = (directive_name, [directive_value])
    elif enum_start or single_line_enum:
      if self._generator_directives.empty:
        return
      self._current_definition = EnumDefinition(
          original_enum_name=enum_start.groups()[1],
          fixed_type=enum_start.groups()[3])
      self._in_enum = True
      if single_line_enum:
        self._ParseSingleLineEnum(single_line_enum.group('enum_entries'))


def DoGenerate(source_paths):
  for source_path in source_paths:
    enum_definitions = DoParseHeaderFile(source_path)
    if not enum_definitions:
      raise Exception('No enums found in %s\n'
                      'Did you forget prefixing enums with '
                      '"// GENERATED_JAVA_ENUM_PACKAGE: foo"?' %
                      source_path)
    for enum_definition in enum_definitions:
      output_path = java_cpp_utils.GetJavaFilePath(enum_definition.enum_package,
                                                   enum_definition.class_name)
      output = GenerateOutput(source_path, enum_definition)
      yield output_path, output


def DoParseHeaderFile(path):
  with open(path, encoding='utf-8') as f:
    return HeaderParser(f.readlines(), path).ParseDefinitions()


def GenerateOutput(source_path, enum_definition):
  template = Template("""
// Copyright ${YEAR} The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This file is autogenerated by
//     ${SCRIPT_NAME}
// From
//     ${SOURCE_PATH}

package ${PACKAGE};

import androidx.annotation.IntDef;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@IntDef(${FLAG_DEF}{
${INT_DEF}
})
@Target(ElementType.TYPE_USE)
@Retention(RetentionPolicy.SOURCE)
public @interface ${CLASS_NAME} {
${ENUM_ENTRIES}
}
""")

  enum_template = Template('  int ${NAME} = ${VALUE};')
  enum_entries_string = []
  enum_names = []
  for enum_name, enum_value in enum_definition.entries.items():
    values = {
        'NAME': enum_name,
        'VALUE': enum_value,
    }
    enum_comments = enum_definition.comments.get(enum_name)
    if enum_comments:
      enum_comments_indent = '   * '
      comments_line_wrapper = textwrap.TextWrapper(
          initial_indent=enum_comments_indent,
          subsequent_indent=enum_comments_indent,
          width=100)
      enum_entries_string.append('  /**')
      enum_entries_string.append('\n'.join(
          comments_line_wrapper.wrap(enum_comments)))
      enum_entries_string.append('   */')
    enum_entries_string.append(enum_template.substitute(values))
    if enum_name != "NUM_ENTRIES":
      enum_names.append(enum_definition.class_name + '.' + enum_name)
  enum_entries_string = '\n'.join(enum_entries_string)

  enum_names_indent = ' ' * 4
  wrapper = textwrap.TextWrapper(initial_indent = enum_names_indent,
                                 subsequent_indent = enum_names_indent,
                                 width = 100)
  enum_names_string = '\n'.join(wrapper.wrap(', '.join(enum_names)))

  values = {
      'CLASS_NAME': enum_definition.class_name,
      'ENUM_ENTRIES': enum_entries_string,
      'PACKAGE': enum_definition.enum_package,
      'FLAG_DEF': 'flag = true, value = ' if enum_definition.is_flag else '',
      'INT_DEF': enum_names_string,
      'SCRIPT_NAME': java_cpp_utils.GetScriptName(),
      'SOURCE_PATH': source_path,
      'YEAR': str(date.today().year),
  }
  return template.substitute(values)


def DoMain(argv):
  parser = argparse.ArgumentParser()

  parser.add_argument('--srcjar',
                      help='When specified, a .srcjar at the given path is '
                      'created instead of individual .java files.')
  parser.add_argument('input_paths',
                      nargs='+',
                      help='Path to at least one input file.')

  options = parser.parse_args(argv)

  with action_helpers.atomic_output(options.srcjar) as f:
    with zipfile.ZipFile(f, 'w', zipfile.ZIP_STORED) as srcjar:
      for output_path, data in DoGenerate(options.input_paths):
        zip_helpers.add_to_zip_hermetic(srcjar, output_path, data=data)


if __name__ == '__main__':
  DoMain(sys.argv[1:])