#!/usr/bin/env python
# Copyright 2014 the V8 project authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# This script retrieves the history of all V8 branches and trunk revisions and
# their corresponding Chromium revisions.

import argparse
import csv
import itertools
import json
import os
import re
import sys

from common_includes import *

DEPS_FILE = "DEPS_FILE"
CHROMIUM = "CHROMIUM"

CONFIG = {
  BRANCHNAME: "retrieve-v8-releases",
  TEMP_BRANCH: "unused-branch", # TODO(machenbach): Remove from infrastructure.
  PERSISTFILE_BASENAME: "/tmp/v8-releases-tempfile",
  DOT_GIT_LOCATION: ".git",
  VERSION_FILE: "src/version.cc",
  DEPS_FILE: "DEPS",
}

# Expression for retrieving the bleeding edge revision from a commit message.
PUSH_MESSAGE_RE = re.compile(r".* \(based on bleeding_edge revision r(\d+)\)$")

# Expression for retrieving the merged patches from a merge commit message
# (old and new format).
MERGE_MESSAGE_RE = re.compile(r"^.*[M|m]erged (.+)(\)| into).*$", re.M)

# Expression for retrieving reverted patches from a commit message (old and
# new format).
ROLLBACK_MESSAGE_RE = re.compile(r"^.*[R|r]ollback of (.+)(\)| in).*$", re.M)

# Expression for retrieving the code review link.
REVIEW_LINK_RE = re.compile(r"^Review URL: (.+)$", re.M)

# Expression with three versions (historical) for extracting the v8 revision
# from the chromium DEPS file.
DEPS_RE = re.compile(r'^\s*(?:"v8_revision": "'
                      '|\(Var\("googlecode_url"\) % "v8"\) \+ "\/trunk@'
                      '|"http\:\/\/v8\.googlecode\.com\/svn\/trunk@)'
                      '([0-9]+)".*$', re.M)


def SortingKey(version):
  """Key for sorting version number strings: '3.11' > '3.2.1.1'"""
  version_keys = map(int, version.split("."))
  # Fill up to full version numbers to normalize comparison.
  while len(version_keys) < 4:
    version_keys.append(0)
  # Fill digits.
  return ".".join(map("{0:03d}".format, version_keys))


def SortBranches(branches):
  """Sort branches with version number names."""
  return sorted(branches, key=SortingKey, reverse=True)


def FilterDuplicatesAndReverse(cr_releases):
  """Returns the chromium releases in reverse order filtered by v8 revision
  duplicates.

  cr_releases is a list of [cr_rev, v8_rev] reverse-sorted by cr_rev.
  """
  last = ""
  result = []
  for release in reversed(cr_releases):
    if last == release[1]:
      continue
    last = release[1]
    result.append(release)
  return result


def BuildRevisionRanges(cr_releases):
  """Returns a mapping of v8 revision -> chromium ranges.
  The ranges are comma-separated, each range has the form R1:R2. The newest
  entry is the only one of the form R1, as there is no end range.

  cr_releases is a list of [cr_rev, v8_rev] reverse-sorted by cr_rev.
  """
  range_lists = {}
  cr_releases = FilterDuplicatesAndReverse(cr_releases)

  # Visit pairs of cr releases from oldest to newest.
  for cr_from, cr_to in itertools.izip(
      cr_releases, itertools.islice(cr_releases, 1, None)):

    # Assume the chromium revisions are all different.
    assert cr_from[0] != cr_to[0]

    # TODO(machenbach): Subtraction is not git friendly.
    ran = "%s:%d" % (cr_from[0], int(cr_to[0]) - 1)

    # Collect the ranges in lists per revision.
    range_lists.setdefault(cr_from[1], []).append(ran)

  # Add the newest revision.
  if cr_releases:
    range_lists.setdefault(cr_releases[-1][1], []).append(cr_releases[-1][0])

  # Stringify and comma-separate the range lists.
  return dict((rev, ", ".join(ran)) for rev, ran in range_lists.iteritems())


def MatchSafe(match):
  if match:
    return match.group(1)
  else:
    return ""


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

  def RunStep(self):
    self.CommonPrepare()
    self.PrepareBranch()


class RetrieveV8Releases(Step):
  MESSAGE = "Retrieve all V8 releases."

  def ExceedsMax(self, releases):
    return (self._options.max_releases > 0
            and len(releases) > self._options.max_releases)

  def GetBleedingEdgeFromPush(self, title):
    return MatchSafe(PUSH_MESSAGE_RE.match(title))

  def GetMergedPatches(self, body):
    patches = MatchSafe(MERGE_MESSAGE_RE.search(body))
    if not patches:
      patches = MatchSafe(ROLLBACK_MESSAGE_RE.search(body))
      if patches:
        # Indicate reverted patches with a "-".
        patches = "-%s" % patches
    return patches

  def GetRelease(self, git_hash, branch):
    self.ReadAndPersistVersion()
    base_version = [self["major"], self["minor"], self["build"]]
    version = ".".join(base_version)
    body = self.GitLog(n=1, format="%B", git_hash=git_hash)

    patches = ""
    if self["patch"] != "0":
      version += ".%s" % self["patch"]
      patches = self.GetMergedPatches(body)

    title = self.GitLog(n=1, format="%s", git_hash=git_hash)
    revision = self.GitSVNFindSVNRev(git_hash)
    return {
      # The SVN revision on the branch.
      "revision": revision,
      # The SVN revision on bleeding edge (only for newer trunk pushes).
      "bleeding_edge": self.GetBleedingEdgeFromPush(title),
      # The branch name.
      "branch": branch,
      # The version for displaying in the form 3.26.3 or 3.26.3.12.
      "version": version,
      # The date of the commit.
      "date": self.GitLog(n=1, format="%ci", git_hash=git_hash),
      # Merged patches if available in the form 'r1234, r2345'.
      "patches_merged": patches,
      # Default for easier output formatting.
      "chromium_revision": "",
      # Link to the CL on code review. Trunk pushes are not uploaded, so this
      # field will be populated below with the recent roll CL link.
      "review_link": MatchSafe(REVIEW_LINK_RE.search(body)),
      # Link to the commit message on google code.
      "revision_link": ("https://code.google.com/p/v8/source/detail?r=%s"
                        % revision),
    }, self["patch"]

  def GetReleasesFromBranch(self, branch):
    self.GitReset("svn/%s" % branch)
    releases = []
    try:
      for git_hash in self.GitLog(format="%H").splitlines():
        if self._config[VERSION_FILE] not in self.GitChangedFiles(git_hash):
          continue
        if self.ExceedsMax(releases):
          break  # pragma: no cover
        if not self.GitCheckoutFileSafe(self._config[VERSION_FILE], git_hash):
          break  # pragma: no cover

        release, patch_level = self.GetRelease(git_hash, branch)
        releases.append(release)

        # Follow branches only until their creation point.
        # TODO(machenbach): This omits patches if the version file wasn't
        # manipulated correctly. Find a better way to detect the point where
        # the parent of the branch head leads to the trunk branch.
        if branch != "trunk" and patch_level == "0":
          break

    # Allow Ctrl-C interrupt.
    except (KeyboardInterrupt, SystemExit):  # pragma: no cover
      pass

    # Clean up checked-out version file.
    self.GitCheckoutFileSafe(self._config[VERSION_FILE], "HEAD")
    return releases

  def RunStep(self):
    self.GitCreateBranch(self._config[BRANCHNAME])
    # Get relevant remote branches, e.g. "svn/3.25".
    branches = filter(lambda s: re.match(r"^svn/\d+\.\d+$", s),
                      self.GitRemotes())
    # Remove 'svn/' prefix.
    branches = map(lambda s: s[4:], branches)

    releases = []
    if self._options.branch == 'recent':
      # Get only recent development on trunk, beta and stable.
      if self._options.max_releases == 0:  # pragma: no cover
        self._options.max_releases = 10
      beta, stable = SortBranches(branches)[0:2]
      releases += self.GetReleasesFromBranch(stable)
      releases += self.GetReleasesFromBranch(beta)
      releases += self.GetReleasesFromBranch("trunk")
    elif self._options.branch == 'all':  # pragma: no cover
      # Retrieve the full release history.
      for branch in branches:
        releases += self.GetReleasesFromBranch(branch)
      releases += self.GetReleasesFromBranch("trunk")
    else:  # pragma: no cover
      # Retrieve history for a specified branch.
      assert self._options.branch in branches + ["trunk"]
      releases += self.GetReleasesFromBranch(self._options.branch)

    self["releases"] = sorted(releases,
                              key=lambda r: SortingKey(r["version"]),
                              reverse=True)


# TODO(machenbach): Parts of the Chromium setup are c/p from the chromium_roll
# script -> unify.
class CheckChromium(Step):
  MESSAGE = "Check the chromium checkout."

  def Run(self):
    self["chrome_path"] = self._options.chromium


class SwitchChromium(Step):
  MESSAGE = "Switch to Chromium checkout."
  REQUIRES = "chrome_path"

  def RunStep(self):
    self["v8_path"] = os.getcwd()
    os.chdir(self["chrome_path"])
    # Check for a clean workdir.
    if not self.GitIsWorkdirClean():  # pragma: no cover
      self.Die("Workspace is not clean. Please commit or undo your changes.")
    # Assert that the DEPS file is there.
    if not os.path.exists(self.Config(DEPS_FILE)):  # pragma: no cover
      self.Die("DEPS file not present.")


class UpdateChromiumCheckout(Step):
  MESSAGE = "Update the checkout and create a new branch."
  REQUIRES = "chrome_path"

  def RunStep(self):
    os.chdir(self["chrome_path"])
    self.GitCheckout("master")
    self.GitPull()
    self.GitCreateBranch(self.Config(BRANCHNAME))


class RetrieveChromiumV8Releases(Step):
  MESSAGE = "Retrieve V8 releases from Chromium DEPS."
  REQUIRES = "chrome_path"

  def RunStep(self):
    os.chdir(self["chrome_path"])

    trunk_releases = filter(lambda r: r["branch"] == "trunk", self["releases"])
    if not trunk_releases:  # pragma: no cover
      print "No trunk releases detected. Skipping chromium history."
      return True

    oldest_v8_rev = int(trunk_releases[-1]["revision"])

    cr_releases = []
    try:
      for git_hash in self.GitLog(format="%H", grep="V8").splitlines():
        if self._config[DEPS_FILE] not in self.GitChangedFiles(git_hash):
          continue
        if not self.GitCheckoutFileSafe(self._config[DEPS_FILE], git_hash):
          break  # pragma: no cover
        deps = FileToText(self.Config(DEPS_FILE))
        match = DEPS_RE.search(deps)
        if match:
          svn_rev = self.GitSVNFindSVNRev(git_hash)
          v8_rev = match.group(1)
          cr_releases.append([svn_rev, v8_rev])

          # Stop after reaching beyond the last v8 revision we want to update.
          # We need a small buffer for possible revert/reland frenzies.
          # TODO(machenbach): Subtraction is not git friendly.
          if int(v8_rev) < oldest_v8_rev - 100:
            break  # pragma: no cover

    # Allow Ctrl-C interrupt.
    except (KeyboardInterrupt, SystemExit):  # pragma: no cover
      pass

    # Clean up.
    self.GitCheckoutFileSafe(self._config[DEPS_FILE], "HEAD")

    # Add the chromium ranges to the v8 trunk releases.
    all_ranges = BuildRevisionRanges(cr_releases)
    trunk_dict = dict((r["revision"], r) for r in trunk_releases)
    for revision, ranges in all_ranges.iteritems():
      trunk_dict.get(revision, {})["chromium_revision"] = ranges

class SwitchV8(Step):
  MESSAGE = "Returning to V8 checkout."
  REQUIRES = "chrome_path"

  def RunStep(self):
    self.GitCheckout("master")
    self.GitDeleteBranch(self.Config(BRANCHNAME))
    os.chdir(self["v8_path"])


class CleanUp(Step):
  MESSAGE = "Clean up."

  def RunStep(self):
    self.CommonCleanup()


class WriteOutput(Step):
  MESSAGE = "Print output."

  def Run(self):
    if self._options.csv:
      with open(self._options.csv, "w") as f:
        writer = csv.DictWriter(f,
                                ["version", "branch", "revision",
                                 "chromium_revision", "patches_merged"],
                                restval="",
                                extrasaction="ignore")
        for release in self["releases"]:
          writer.writerow(release)
    if self._options.json:
      with open(self._options.json, "w") as f:
        f.write(json.dumps(self["releases"]))
    if not self._options.csv and not self._options.json:
      print self["releases"]  # pragma: no cover


class Releases(ScriptsBase):
  def _PrepareOptions(self, parser):
    parser.add_argument("-b", "--branch", default="recent",
                        help=("The branch to analyze. If 'all' is specified, "
                              "analyze all branches. If 'recent' (default) "
                              "is specified, track beta, stable and trunk."))
    parser.add_argument("-c", "--chromium",
                        help=("The path to your Chromium src/ "
                              "directory to automate the V8 roll."))
    parser.add_argument("--csv", help="Path to a CSV file for export.")
    parser.add_argument("-m", "--max-releases", type=int, default=0,
                        help="The maximum number of releases to track.")
    parser.add_argument("--json", help="Path to a JSON file for export.")

  def _ProcessOptions(self, options):  # pragma: no cover
    return True

  def _Steps(self):
    return [
      Preparation,
      RetrieveV8Releases,
      CheckChromium,
      SwitchChromium,
      UpdateChromiumCheckout,
      RetrieveChromiumV8Releases,
      SwitchV8,
      CleanUp,
      WriteOutput,
    ]


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