#!/usr/bin/python

# Copyright (c) 2014, Facebook, Inc.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree. An additional grant
# of patent rights can be found in the PATENTS file in the same directory.

import lldb

import imp
import os
import shlex
import sys
from optparse import OptionParser

import fblldbbase as fb

def __lldb_init_module(debugger, dict):
  filePath = os.path.realpath(__file__)
  lldbHelperDir = os.path.dirname(filePath)

  commandsDirectory = os.path.join(lldbHelperDir, 'commands')
  loadCommandsInDirectory(commandsDirectory)

def loadCommandsInDirectory(commandsDirectory):
  for file in os.listdir(commandsDirectory):
    fileName, fileExtension = os.path.splitext(file)
    if fileExtension == '.py':
      module = imp.load_source(fileName, os.path.join(commandsDirectory, file))

      if hasattr(module, 'lldbinit'):
        module.lldbinit()

      if hasattr(module, 'lldbcommands'):
        module._loadedFunctions = {}
        for command in module.lldbcommands():
          loadCommand(module, command, commandsDirectory, fileName, fileExtension)

def loadCommand(module, command, directory, filename, extension):
  func = makeRunCommand(command, os.path.join(directory, filename + extension))
  name = command.name()

  key = filename + '_' + name

  module._loadedFunctions[key] = func

  functionName = '__' + key

  lldb.debugger.HandleCommand('script ' + functionName + ' = sys.modules[\'' + module.__name__ + '\']._loadedFunctions[\'' + key + '\']')
  lldb.debugger.HandleCommand('command script add -f ' + functionName + ' ' + name)

def makeRunCommand(command, filename):
  def runCommand(debugger, input, result, dict):
    splitInput = shlex.split(input)
    options = None
    args = None

    # OptionParser will throw in the case where you want just one big long argument and no
    # options and you enter something that starts with '-' in the argument. e.g.:
    #     somecommand -[SomeClass someSelector:]
    # This solves that problem by prepending a '--' so that OptionParser does the right
    # thing.
    options = command.options()
    if len(options) == 0:
      if '--' not in splitInput:
        splitInput.insert(0, '--')

    parser = optionParserForCommand(command)
    (options, args) = parser.parse_args(splitInput)

    # When there are more args than the command has declared, assume
    # the initial args form an expression and combine them into a single arg.
    if len(args) > len(command.args()):
      overhead = len(args) - len(command.args())
      head = args[:overhead + 1] # Take N+1 and reduce to 1.
      args = [' '.join(head)] + args[-overhead:]

    if validateArgsForCommand(args, command):
      command.run(args, options)

  runCommand.__doc__ = helpForCommand(command, filename)
  return runCommand

def validateArgsForCommand(args, command):
  if len(args) < len(command.args()):
    defaultArgs = [arg.default for arg in command.args()]
    defaultArgsToAppend = defaultArgs[len(args):]

    index = len(args)
    for defaultArg in defaultArgsToAppend:
      if not defaultArg:
        arg = command.args()[index]
        print 'Whoops! You are missing the <' + arg.argName + '> argument.'
        print '\nUsage: ' + usageForCommand(command)
        return
      index += 1

    args.extend(defaultArgsToAppend)
  return True

def optionParserForCommand(command):
  parser = OptionParser()

  for argument in command.options():
    if argument.boolean:
      parser.add_option(argument.shortName, argument.longName, dest=argument.argName,
                        help=argument.help, action=("store_false" if argument.default else "store_true"))
    else:
      parser.add_option(argument.shortName, argument.longName, dest=argument.argName,
                        help=argument.help, default=argument.default)

  return parser

def helpForCommand(command, filename):
  help = command.description()

  argSyntax = ''
  optionSyntax = ''

  if command.args():
    help += '\n\nArguments:'
    for arg in command.args():
      help += '\n  <' + arg.argName + '>; Type: ' + arg.argType + '; ' + arg.help
      argSyntax += ' <' + arg.argName + '>'

  if command.options():
    help += '\n\nOptions:'
    for option in command.options():

      optionFlag = ''
      if option.longName and option.shortName:
        optionFlag = option.longName + '/' + option.shortName
      elif option.longName:
        optionFlag = option.longName
      else:
        optionFlag = optiob.shortName

      help += '\n  ' + optionFlag + ' '

      if not option.boolean:
        help += '<' + option.argName + '>; Type: ' + option.argType

      help += '; ' + option.help

      optionSyntax += ' [{name}{arg}]'.format(
        name=(option.longName or option.shortName),
        arg=('' if option.boolean else ('=' + option.argName))
      )

  help += '\n\nSyntax: ' + command.name() + optionSyntax + argSyntax

  help += '\n\nThis command is implemented as %s in %s.' % (command.__class__.__name__, filename)

  help += '\n\n(LLDB adds the next line, sorry...)'

  return help

def usageForCommand(command):
  usage = command.name()
  for arg in command.args():
    if arg.default:
      usage += ' [' + arg.argName + ']'
    else:
      usage += ' ' + arg.argName

  return usage