#!/usr/bin/env python
# Copyright 2014 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 argparse
from collections import OrderedDict
import sys

from common_includes import *

def IsSvnNumber(rev):
  return rev.isdigit() and len(rev) < 8

class Preparation(Step):
  MESSAGE = "Preparation."

  def RunStep(self):
    if os.path.exists(self.Config("ALREADY_MERGING_SENTINEL_FILE")):
      if self._options.force:
        os.remove(self.Config("ALREADY_MERGING_SENTINEL_FILE"))
      elif self._options.step == 0:  # pragma: no cover
        self.Die("A merge is already in progress")
    open(self.Config("ALREADY_MERGING_SENTINEL_FILE"), "a").close()

    self.InitialEnvironmentChecks(self.default_cwd)
    if self._options.revert_master:
      # FIXME(machenbach): Make revert master obsolete?
      self["merge_to_branch"] = "master"
    elif self._options.branch:
      self["merge_to_branch"] = self._options.branch
    else:  # pragma: no cover
      self.Die("Please specify a branch to merge to")

    self.CommonPrepare()
    self.PrepareBranch()


class CreateBranch(Step):
  MESSAGE = "Create a fresh branch for the patch."

  def RunStep(self):
    self.GitCreateBranch(self.Config("BRANCHNAME"),
                         self.vc.RemoteBranch(self["merge_to_branch"]))


class SearchArchitecturePorts(Step):
  MESSAGE = "Search for corresponding architecture ports."

  def RunStep(self):
    self["full_revision_list"] = list(OrderedDict.fromkeys(
        self._options.revisions))
    port_revision_list = []
    for revision in self["full_revision_list"]:
      # Search for commits which matches the "Port XXX" pattern.
      git_hashes = self.GitLog(reverse=True, format="%H",
                               grep="Port %s" % revision,
                               branch=self.vc.RemoteMasterBranch())
      for git_hash in git_hashes.splitlines():
        revision_title = self.GitLog(n=1, format="%s", git_hash=git_hash)

        # Is this revision included in the original revision list?
        if git_hash in self["full_revision_list"]:
          print("Found port of %s -> %s (already included): %s"
                % (revision, git_hash, revision_title))
        else:
          print("Found port of %s -> %s: %s"
                % (revision, git_hash, revision_title))
          port_revision_list.append(git_hash)

    # Do we find any port?
    if len(port_revision_list) > 0:
      if self.Confirm("Automatically add corresponding ports (%s)?"
                      % ", ".join(port_revision_list)):
        #: 'y': Add ports to revision list.
        self["full_revision_list"].extend(port_revision_list)


class CreateCommitMessage(Step):
  MESSAGE = "Create commit message."

  def RunStep(self):

    # Stringify: [123, 234] -> "r123, r234"
    self["revision_list"] = ", ".join(map(lambda s: "r%s" % s,
                                      self["full_revision_list"]))

    if not self["revision_list"]:  # pragma: no cover
      self.Die("Revision list is empty.")

    if self._options.revert and not self._options.revert_master:
      action_text = "Rollback of %s"
    else:
      action_text = "Merged %s"

    # The commit message title is added below after the version is specified.
    msg_pieces = [
      "\n".join(action_text % s for s in self["full_revision_list"]),
    ]
    msg_pieces.append("\n\n")

    for commit_hash in self["full_revision_list"]:
      patch_merge_desc = self.GitLog(n=1, format="%s", git_hash=commit_hash)
      msg_pieces.append("%s\n\n" % patch_merge_desc)

    bugs = []
    for commit_hash in self["full_revision_list"]:
      msg = self.GitLog(n=1, git_hash=commit_hash)
      for bug in re.findall(r"^[ \t]*BUG[ \t]*=[ \t]*(.*?)[ \t]*$", msg, re.M):
        bugs.extend(s.strip() for s in bug.split(","))
    bug_aggregate = ",".join(sorted(filter(lambda s: s and s != "none", bugs)))
    if bug_aggregate:
      msg_pieces.append("BUG=%s\nLOG=N\n" % bug_aggregate)

    self["new_commit_msg"] = "".join(msg_pieces)


class ApplyPatches(Step):
  MESSAGE = "Apply patches for selected revisions."

  def RunStep(self):
    for commit_hash in self["full_revision_list"]:
      print("Applying patch for %s to %s..."
            % (commit_hash, self["merge_to_branch"]))
      patch = self.GitGetPatch(commit_hash)
      TextToFile(patch, self.Config("TEMPORARY_PATCH_FILE"))
      self.ApplyPatch(self.Config("TEMPORARY_PATCH_FILE"), self._options.revert)
    if self._options.patch:
      self.ApplyPatch(self._options.patch, self._options.revert)


class PrepareVersion(Step):
  MESSAGE = "Prepare version file."

  def RunStep(self):
    if self._options.revert_master:
      return
    # This is used to calculate the patch level increment.
    self.ReadAndPersistVersion()


class IncrementVersion(Step):
  MESSAGE = "Increment version number."

  def RunStep(self):
    if self._options.revert_master:
      return
    new_patch = str(int(self["patch"]) + 1)
    if self.Confirm("Automatically increment PATCH_LEVEL? (Saying 'n' will "
                    "fire up your EDITOR on %s so you can make arbitrary "
                    "changes. When you're done, save the file and exit your "
                    "EDITOR.)" % VERSION_FILE):
      text = FileToText(os.path.join(self.default_cwd, VERSION_FILE))
      text = MSub(r"(?<=#define PATCH_LEVEL)(?P<space>\s+)\d*$",
                  r"\g<space>%s" % new_patch,
                  text)
      TextToFile(text, os.path.join(self.default_cwd, VERSION_FILE))
    else:
      self.Editor(os.path.join(self.default_cwd, VERSION_FILE))
    self.ReadAndPersistVersion("new_")
    self["version"] = "%s.%s.%s.%s" % (self["new_major"],
                                       self["new_minor"],
                                       self["new_build"],
                                       self["new_patch"])


class CommitLocal(Step):
  MESSAGE = "Commit to local branch."

  def RunStep(self):
    # Add a commit message title.
    if self._options.revert and self._options.revert_master:
      # TODO(machenbach): Find a better convention if multiple patches are
      # reverted in one CL.
      self["commit_title"] = "Revert on master"
    else:
      self["commit_title"] = "Version %s (cherry-pick)" % self["version"]
    self["new_commit_msg"] = "%s\n\n%s" % (self["commit_title"],
                                           self["new_commit_msg"])
    TextToFile(self["new_commit_msg"], self.Config("COMMITMSG_FILE"))
    self.GitCommit(file_name=self.Config("COMMITMSG_FILE"))


class CommitRepository(Step):
  MESSAGE = "Commit to the repository."

  def RunStep(self):
    self.GitCheckout(self.Config("BRANCHNAME"))
    self.WaitForLGTM()
    self.GitPresubmit()
    self.vc.CLLand()


class TagRevision(Step):
  MESSAGE = "Create the tag."

  def RunStep(self):
    if self._options.revert_master:
      return
    print "Creating tag %s" % self["version"]
    self.vc.Tag(self["version"],
                self.vc.RemoteBranch(self["merge_to_branch"]),
                self["commit_title"])


class CleanUp(Step):
  MESSAGE = "Cleanup."

  def RunStep(self):
    self.CommonCleanup()
    if not self._options.revert_master:
      print "*** SUMMARY ***"
      print "version: %s" % self["version"]
      print "branch: %s" % self["merge_to_branch"]
      if self["revision_list"]:
        print "patches: %s" % self["revision_list"]


class MergeToBranch(ScriptsBase):
  def _Description(self):
    return ("Performs the necessary steps to merge revisions from "
            "master to other branches, including candidates.")

  def _PrepareOptions(self, parser):
    group = parser.add_mutually_exclusive_group(required=True)
    group.add_argument("--branch", help="The branch to merge to.")
    group.add_argument("-R", "--revert-master",
                       help="Revert specified patches from master.",
                       default=False, action="store_true")
    parser.add_argument("revisions", nargs="*",
                        help="The revisions to merge.")
    parser.add_argument("-f", "--force",
                        help="Delete sentinel file.",
                        default=False, action="store_true")
    parser.add_argument("-m", "--message",
                        help="A commit message for the patch.")
    parser.add_argument("--revert",
                        help="Revert specified patches.",
                        default=False, action="store_true")
    parser.add_argument("-p", "--patch",
                        help="A patch file to apply as part of the merge.")

  def _ProcessOptions(self, options):
    # TODO(machenbach): Add a test that covers revert from master
    if len(options.revisions) < 1:
      if not options.patch:
        print "Either a patch file or revision numbers must be specified"
        return False
      if not options.message:
        print "You must specify a merge comment if no patches are specified"
        return False
    options.bypass_upload_hooks = True
    # CC ulan to make sure that fixes are merged to Google3.
    options.cc = "ulan@chromium.org"

    # Make sure to use git hashes in the new workflows.
    for revision in options.revisions:
      if (IsSvnNumber(revision) or
          (revision[0:1] == "r" and IsSvnNumber(revision[1:]))):
        print "Please provide full git hashes of the patches to merge."
        print "Got: %s" % revision
        return False
    return True

  def _Config(self):
    return {
      "BRANCHNAME": "prepare-merge",
      "PERSISTFILE_BASENAME": "/tmp/v8-merge-to-branch-tempfile",
      "ALREADY_MERGING_SENTINEL_FILE":
          "/tmp/v8-merge-to-branch-tempfile-already-merging",
      "TEMPORARY_PATCH_FILE": "/tmp/v8-prepare-merge-tempfile-temporary-patch",
      "COMMITMSG_FILE": "/tmp/v8-prepare-merge-tempfile-commitmsg",
    }

  def _Steps(self):
    return [
      Preparation,
      CreateBranch,
      SearchArchitecturePorts,
      CreateCommitMessage,
      ApplyPatches,
      PrepareVersion,
      IncrementVersion,
      CommitLocal,
      UploadStep,
      CommitRepository,
      TagRevision,
      CleanUp,
    ]


if __name__ == "__main__":  # pragma: no cover
  sys.exit(MergeToBranch().Run())