#!/usr/bin/env python
# Copyright 2013 the V8 project authors. All rights reserved.
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
#       copyright notice, this list of conditions and the following
#       disclaimer in the documentation and/or other materials provided
#       with the distribution.
#     * Neither the name of Google Inc. nor the names of its
#       contributors may be used to endorse or promote products derived
#       from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import datetime
import json
import os
import re
import subprocess
import sys
import textwrap
import time
import urllib2

from git_recipes import GitRecipesMixin

PERSISTFILE_BASENAME = "PERSISTFILE_BASENAME"
TEMP_BRANCH = "TEMP_BRANCH"
BRANCHNAME = "BRANCHNAME"
DOT_GIT_LOCATION = "DOT_GIT_LOCATION"
VERSION_FILE = "VERSION_FILE"
CHANGELOG_FILE = "CHANGELOG_FILE"
CHANGELOG_ENTRY_FILE = "CHANGELOG_ENTRY_FILE"
COMMITMSG_FILE = "COMMITMSG_FILE"
PATCH_FILE = "PATCH_FILE"


def TextToFile(text, file_name):
  with open(file_name, "w") as f:
    f.write(text)


def AppendToFile(text, file_name):
  with open(file_name, "a") as f:
    f.write(text)


def LinesInFile(file_name):
  with open(file_name) as f:
    for line in f:
      yield line


def FileToText(file_name):
  with open(file_name) as f:
    return f.read()


def MSub(rexp, replacement, text):
  return re.sub(rexp, replacement, text, flags=re.MULTILINE)


def Fill80(line):
  # Replace tabs and remove surrounding space.
  line = re.sub(r"\t", r"        ", line.strip())

  # Format with 8 characters indentation and line width 80.
  return textwrap.fill(line, width=80, initial_indent="        ",
                       subsequent_indent="        ")


def GetLastChangeLogEntries(change_log_file):
  result = []
  for line in LinesInFile(change_log_file):
    if re.search(r"^\d{4}-\d{2}-\d{2}:", line) and result: break
    result.append(line)
  return "".join(result)


def MakeComment(text):
  return MSub(r"^( ?)", "#", text)


def StripComments(text):
  # Use split not splitlines to keep terminal newlines.
  return "\n".join(filter(lambda x: not x.startswith("#"), text.split("\n")))


def MakeChangeLogBody(commit_messages, auto_format=False):
  result = ""
  added_titles = set()
  for (title, body, author) in commit_messages:
    # TODO(machenbach): Better check for reverts. A revert should remove the
    # original CL from the actual log entry.
    title = title.strip()
    if auto_format:
      # Only add commits that set the LOG flag correctly.
      log_exp = r"^[ \t]*LOG[ \t]*=[ \t]*(?:(?:Y(?:ES)?)|TRUE)"
      if not re.search(log_exp, body, flags=re.I | re.M):
        continue
      # Never include reverts.
      if title.startswith("Revert "):
        continue
      # Don't include duplicates.
      if title in added_titles:
        continue

    # Add and format the commit's title and bug reference. Move dot to the end.
    added_titles.add(title)
    raw_title = re.sub(r"(\.|\?|!)$", "", title)
    bug_reference = MakeChangeLogBugReference(body)
    space = " " if bug_reference else ""
    result += "%s\n" % Fill80("%s%s%s." % (raw_title, space, bug_reference))

    # Append the commit's author for reference if not in auto-format mode.
    if not auto_format:
      result += "%s\n" % Fill80("(%s)" % author.strip())

    result += "\n"
  return result


def MakeChangeLogBugReference(body):
  """Grep for "BUG=xxxx" lines in the commit message and convert them to
  "(issue xxxx)".
  """
  crbugs = []
  v8bugs = []

  def AddIssues(text):
    ref = re.match(r"^BUG[ \t]*=[ \t]*(.+)$", text.strip())
    if not ref:
      return
    for bug in ref.group(1).split(","):
      bug = bug.strip()
      match = re.match(r"^v8:(\d+)$", bug)
      if match: v8bugs.append(int(match.group(1)))
      else:
        match = re.match(r"^(?:chromium:)?(\d+)$", bug)
        if match: crbugs.append(int(match.group(1)))

  # Add issues to crbugs and v8bugs.
  map(AddIssues, body.splitlines())

  # Filter duplicates, sort, stringify.
  crbugs = map(str, sorted(set(crbugs)))
  v8bugs = map(str, sorted(set(v8bugs)))

  bug_groups = []
  def FormatIssues(prefix, bugs):
    if len(bugs) > 0:
      plural = "s" if len(bugs) > 1 else ""
      bug_groups.append("%sissue%s %s" % (prefix, plural, ", ".join(bugs)))

  FormatIssues("", v8bugs)
  FormatIssues("Chromium ", crbugs)

  if len(bug_groups) > 0:
    return "(%s)" % ", ".join(bug_groups)
  else:
    return ""


# Some commands don't like the pipe, e.g. calling vi from within the script or
# from subscripts like git cl upload.
def Command(cmd, args="", prefix="", pipe=True):
  # TODO(machenbach): Use timeout.
  cmd_line = "%s %s %s" % (prefix, cmd, args)
  print "Command: %s" % cmd_line
  try:
    if pipe:
      return subprocess.check_output(cmd_line, shell=True)
    else:
      return subprocess.check_call(cmd_line, shell=True)
  except subprocess.CalledProcessError:
    return None


# Wrapper for side effects.
class SideEffectHandler(object):
  def Call(self, fun, *args, **kwargs):
    return fun(*args, **kwargs)

  def Command(self, cmd, args="", prefix="", pipe=True):
    return Command(cmd, args, prefix, pipe)

  def ReadLine(self):
    return sys.stdin.readline().strip()

  def ReadURL(self, url, params=None):
    # pylint: disable=E1121
    url_fh = urllib2.urlopen(url, params, 60)
    try:
      return url_fh.read()
    finally:
      url_fh.close()

  def Sleep(self, seconds):
    time.sleep(seconds)

  def GetDate(self):
    return datetime.date.today().strftime("%Y-%m-%d")

DEFAULT_SIDE_EFFECT_HANDLER = SideEffectHandler()


class NoRetryException(Exception):
  pass


class GitFailedException(Exception):
  pass


class CommonOptions(object):
  def __init__(self, options, manual=True):
    self.requires_editor = True
    self.wait_for_lgtm = True
    self.step = options.step
    self.force_readline_defaults = not manual
    self.force_upload = not manual
    self.manual = manual
    self.reviewer = getattr(options, 'reviewer', "")
    self.author = getattr(options, 'author', "")


class Step(GitRecipesMixin):
  def __init__(self, text, requires, number, config, state, options, handler):
    self._text = text
    self._requires = requires
    self._number = number
    self._config = config
    self._state = state
    self._options = options
    self._side_effect_handler = handler
    assert self._number >= 0
    assert self._config is not None
    assert self._state is not None
    assert self._side_effect_handler is not None
    assert isinstance(options, CommonOptions)

  def __getitem__(self, key):
    # Convenience method to allow direct [] access on step classes for
    # manipulating the backed state dict.
    return self._state[key]

  def __setitem__(self, key, value):
    # Convenience method to allow direct [] access on step classes for
    # manipulating the backed state dict.
    self._state[key] = value

  def Config(self, key):
    return self._config[key]

  def Run(self):
    # Restore state.
    state_file = "%s-state.json" % self._config[PERSISTFILE_BASENAME]
    if not self._state and os.path.exists(state_file):
      self._state.update(json.loads(FileToText(state_file)))

    # Skip step if requirement is not met.
    if self._requires and not self._state.get(self._requires):
      return

    print ">>> Step %d: %s" % (self._number, self._text)
    self.RunStep()

    # Persist state.
    TextToFile(json.dumps(self._state), state_file)

  def RunStep(self):
    raise NotImplementedError

  def Retry(self, cb, retry_on=None, wait_plan=None):
    """ Retry a function.
    Params:
      cb: The function to retry.
      retry_on: A callback that takes the result of the function and returns
                True if the function should be retried. A function throwing an
                exception is always retried.
      wait_plan: A list of waiting delays between retries in seconds. The
                 maximum number of retries is len(wait_plan).
    """
    retry_on = retry_on or (lambda x: False)
    wait_plan = list(wait_plan or [])
    wait_plan.reverse()
    while True:
      got_exception = False
      try:
        result = cb()
      except NoRetryException, e:
        raise e
      except Exception:
        got_exception = True
      if got_exception or retry_on(result):
        if not wait_plan:
          raise Exception("Retried too often. Giving up.")
        wait_time = wait_plan.pop()
        print "Waiting for %f seconds." % wait_time
        self._side_effect_handler.Sleep(wait_time)
        print "Retrying..."
      else:
        return result

  def ReadLine(self, default=None):
    # Don't prompt in forced mode.
    if self._options.force_readline_defaults and default is not None:
      print "%s (forced)" % default
      return default
    else:
      return self._side_effect_handler.ReadLine()

  def Git(self, args="", prefix="", pipe=True, retry_on=None):
    cmd = lambda: self._side_effect_handler.Command("git", args, prefix, pipe)
    result = self.Retry(cmd, retry_on, [5, 30])
    if result is None:
      raise GitFailedException("'git %s' failed." % args)
    return result

  def SVN(self, args="", prefix="", pipe=True, retry_on=None):
    cmd = lambda: self._side_effect_handler.Command("svn", args, prefix, pipe)
    return self.Retry(cmd, retry_on, [5, 30])

  def Editor(self, args):
    if self._options.requires_editor:
      return self._side_effect_handler.Command(os.environ["EDITOR"], args,
                                               pipe=False)

  def ReadURL(self, url, params=None, retry_on=None, wait_plan=None):
    wait_plan = wait_plan or [3, 60, 600]
    cmd = lambda: self._side_effect_handler.ReadURL(url, params)
    return self.Retry(cmd, retry_on, wait_plan)

  def GetDate(self):
    return self._side_effect_handler.GetDate()

  def Die(self, msg=""):
    if msg != "":
      print "Error: %s" % msg
    print "Exiting"
    raise Exception(msg)

  def DieNoManualMode(self, msg=""):
    if not self._options.manual:
      msg = msg or "Only available in manual mode."
      self.Die(msg)

  def Confirm(self, msg):
    print "%s [Y/n] " % msg,
    answer = self.ReadLine(default="Y")
    return answer == "" or answer == "Y" or answer == "y"

  def DeleteBranch(self, name):
    for line in self.GitBranch().splitlines():
      if re.match(r".*\s+%s$" % name, line):
        msg = "Branch %s exists, do you want to delete it?" % name
        if self.Confirm(msg):
          self.GitDeleteBranch(name)
          print "Branch %s deleted." % name
        else:
          msg = "Can't continue. Please delete branch %s and try again." % name
          self.Die(msg)

  def InitialEnvironmentChecks(self):
    # Cancel if this is not a git checkout.
    if not os.path.exists(self._config[DOT_GIT_LOCATION]):
      self.Die("This is not a git checkout, this script won't work for you.")

    # Cancel if EDITOR is unset or not executable.
    if (self._options.requires_editor and (not os.environ.get("EDITOR") or
        Command("which", os.environ["EDITOR"]) is None)):
      self.Die("Please set your EDITOR environment variable, you'll need it.")

  def CommonPrepare(self):
    # Check for a clean workdir.
    if not self.GitIsWorkdirClean():
      self.Die("Workspace is not clean. Please commit or undo your changes.")

    # Persist current branch.
    self["current_branch"] = self.GitCurrentBranch()

    # Fetch unfetched revisions.
    self.GitSVNFetch()

  def PrepareBranch(self):
    # Get ahold of a safe temporary branch and check it out.
    if self["current_branch"] != self._config[TEMP_BRANCH]:
      self.DeleteBranch(self._config[TEMP_BRANCH])
      self.GitCreateBranch(self._config[TEMP_BRANCH])

    # Delete the branch that will be created later if it exists already.
    self.DeleteBranch(self._config[BRANCHNAME])

  def CommonCleanup(self):
    self.GitCheckout(self["current_branch"])
    if self._config[TEMP_BRANCH] != self["current_branch"]:
      self.GitDeleteBranch(self._config[TEMP_BRANCH])
    if self._config[BRANCHNAME] != self["current_branch"]:
      self.GitDeleteBranch(self._config[BRANCHNAME])

    # Clean up all temporary files.
    Command("rm", "-f %s*" % self._config[PERSISTFILE_BASENAME])

  def ReadAndPersistVersion(self, prefix=""):
    def ReadAndPersist(var_name, def_name):
      match = re.match(r"^#define %s\s+(\d*)" % def_name, line)
      if match:
        value = match.group(1)
        self["%s%s" % (prefix, var_name)] = value
    for line in LinesInFile(self._config[VERSION_FILE]):
      for (var_name, def_name) in [("major", "MAJOR_VERSION"),
                                   ("minor", "MINOR_VERSION"),
                                   ("build", "BUILD_NUMBER"),
                                   ("patch", "PATCH_LEVEL")]:
        ReadAndPersist(var_name, def_name)

  def WaitForLGTM(self):
    print ("Please wait for an LGTM, then type \"LGTM<Return>\" to commit "
           "your change. (If you need to iterate on the patch or double check "
           "that it's sane, do so in another shell, but remember to not "
           "change the headline of the uploaded CL.")
    answer = ""
    while answer != "LGTM":
      print "> ",
      answer = self.ReadLine(None if self._options.wait_for_lgtm else "LGTM")
      if answer != "LGTM":
        print "That was not 'LGTM'."

  def WaitForResolvingConflicts(self, patch_file):
    print("Applying the patch \"%s\" failed. Either type \"ABORT<Return>\", "
          "or resolve the conflicts, stage *all* touched files with "
          "'git add', and type \"RESOLVED<Return>\"")
    self.DieNoManualMode()
    answer = ""
    while answer != "RESOLVED":
      if answer == "ABORT":
        self.Die("Applying the patch failed.")
      if answer != "":
        print "That was not 'RESOLVED' or 'ABORT'."
      print "> ",
      answer = self.ReadLine()

  # Takes a file containing the patch to apply as first argument.
  def ApplyPatch(self, patch_file, revert=False):
    try:
      self.GitApplyPatch(patch_file, revert)
    except GitFailedException:
      self.WaitForResolvingConflicts(patch_file)

  def FindLastTrunkPush(self, parent_hash=""):
    push_pattern = "^Version [[:digit:]]*\.[[:digit:]]*\.[[:digit:]]* (based"
    branch = "" if parent_hash else "svn/trunk"
    return self.GitLog(n=1, format="%H", grep=push_pattern,
                       parent_hash=parent_hash, branch=branch)


class UploadStep(Step):
  MESSAGE = "Upload for code review."

  def RunStep(self):
    if self._options.reviewer:
      print "Using account %s for review." % self._options.reviewer
      reviewer = self._options.reviewer
    else:
      print "Please enter the email address of a V8 reviewer for your patch: ",
      self.DieNoManualMode("A reviewer must be specified in forced mode.")
      reviewer = self.ReadLine()
    self.GitUpload(reviewer, self._options.author, self._options.force_upload)


def MakeStep(step_class=Step, number=0, state=None, config=None,
             options=None, side_effect_handler=DEFAULT_SIDE_EFFECT_HANDLER):
    # Allow to pass in empty dictionaries.
    state = state if state is not None else {}
    config = config if config is not None else {}

    try:
      message = step_class.MESSAGE
    except AttributeError:
      message = step_class.__name__
    try:
      requires = step_class.REQUIRES
    except AttributeError:
      requires = None

    return step_class(message, requires, number=number, config=config,
                      state=state, options=options,
                      handler=side_effect_handler)


def RunScript(step_classes,
              config,
              options,
              side_effect_handler=DEFAULT_SIDE_EFFECT_HANDLER):
  state_file = "%s-state.json" % config[PERSISTFILE_BASENAME]
  if options.step == 0 and os.path.exists(state_file):
    os.remove(state_file)
  state = {}
  steps = []
  for (number, step_class) in enumerate(step_classes):
    steps.append(MakeStep(step_class, number, state, config,
                          options, side_effect_handler))

  for step in steps[options.step:]:
    step.Run()