# Copyright (c) 2009, Google Inc. All rights reserved.
#
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# WebKit's Python module for interacting with WebKit's buildbot

try:
    import json
except ImportError:
    # python 2.5 compatibility
    import webkitpy.thirdparty.simplejson as json

import operator
import re
import urllib
import urllib2

import webkitpy.common.config.urls as config_urls
from webkitpy.common.net.failuremap import FailureMap
from webkitpy.common.net.layouttestresults import LayoutTestResults
from webkitpy.common.net.networktransaction import NetworkTransaction
from webkitpy.common.net.regressionwindow import RegressionWindow
from webkitpy.common.system.logutils import get_logger
from webkitpy.thirdparty.BeautifulSoup import BeautifulSoup


_log = get_logger(__file__)


class Builder(object):
    def __init__(self, name, buildbot):
        self._name = name
        self._buildbot = buildbot
        self._builds_cache = {}
        self._revision_to_build_number = None
        from webkitpy.thirdparty.autoinstalled.mechanize import Browser
        self._browser = Browser()
        self._browser.set_handle_robots(False) # The builder pages are excluded by robots.txt

    def name(self):
        return self._name

    def results_url(self):
        return "%s/results/%s" % (self._buildbot.buildbot_url, self.url_encoded_name())

    # In addition to per-build results, the build.chromium.org builders also
    # keep a directory that accumulates test results over many runs.
    def accumulated_results_url(self):
        return None

    def url_encoded_name(self):
        return urllib.quote(self._name)

    def url(self):
        return "%s/builders/%s" % (self._buildbot.buildbot_url, self.url_encoded_name())

    # This provides a single place to mock
    def _fetch_build(self, build_number):
        build_dictionary = self._buildbot._fetch_build_dictionary(self, build_number)
        if not build_dictionary:
            return None
        revision_string = build_dictionary['sourceStamp']['revision']
        return Build(self,
            build_number=int(build_dictionary['number']),
            # 'revision' may be None if a trunk build was started by the force-build button on the web page.
            revision=(int(revision_string) if revision_string else None),
            # Buildbot uses any nubmer other than 0 to mean fail.  Since we fetch with
            # filter=1, passing builds may contain no 'results' value.
            is_green=(not build_dictionary.get('results')),
        )

    def build(self, build_number):
        if not build_number:
            return None
        cached_build = self._builds_cache.get(build_number)
        if cached_build:
            return cached_build

        build = self._fetch_build(build_number)
        self._builds_cache[build_number] = build
        return build

    def latest_cached_build(self):
        revision_build_pairs = self.revision_build_pairs_with_results()
        revision_build_pairs.sort(key=lambda i: i[1])
        latest_build_number = revision_build_pairs[-1][1]
        return self.build(latest_build_number)

    def force_build(self, username="webkit-patch", comments=None):
        def predicate(form):
            try:
                return form.find_control("username")
            except Exception, e:
                return False
        self._browser.open(self.url())
        self._browser.select_form(predicate=predicate)
        self._browser["username"] = username
        if comments:
            self._browser["comments"] = comments
        return self._browser.submit()

    file_name_regexp = re.compile(r"r(?P<revision>\d+) \((?P<build_number>\d+)\)")
    def _revision_and_build_for_filename(self, filename):
        # Example: "r47483 (1)/" or "r47483 (1).zip"
        match = self.file_name_regexp.match(filename)
        return (int(match.group("revision")), int(match.group("build_number")))

    def _fetch_revision_to_build_map(self):
        # All _fetch requests go through _buildbot for easier mocking
        # FIXME: This should use NetworkTransaction's 404 handling instead.
        try:
            # FIXME: This method is horribly slow due to the huge network load.
            # FIXME: This is a poor way to do revision -> build mapping.
            # Better would be to ask buildbot through some sort of API.
            print "Loading revision/build list from %s." % self.results_url()
            print "This may take a while..."
            result_files = self._buildbot._fetch_twisted_directory_listing(self.results_url())
        except urllib2.HTTPError, error:
            if error.code != 404:
                raise
            result_files = []

        # This assumes there was only one build per revision, which is false but we don't care for now.
        return dict([self._revision_and_build_for_filename(file_info["filename"]) for file_info in result_files])

    def _revision_to_build_map(self):
        if not self._revision_to_build_number:
            self._revision_to_build_number = self._fetch_revision_to_build_map()
        return self._revision_to_build_number

    def revision_build_pairs_with_results(self):
        return self._revision_to_build_map().items()

    # This assumes there can be only one build per revision, which is false, but we don't care for now.
    def build_for_revision(self, revision, allow_failed_lookups=False):
        # NOTE: This lookup will fail if that exact revision was never built.
        build_number = self._revision_to_build_map().get(int(revision))
        if not build_number:
            return None
        build = self.build(build_number)
        if not build and allow_failed_lookups:
            # Builds for old revisions with fail to lookup via buildbot's json api.
            build = Build(self,
                build_number=build_number,
                revision=revision,
                is_green=False,
            )
        return build

    def find_regression_window(self, red_build, look_back_limit=30):
        if not red_build or red_build.is_green():
            return RegressionWindow(None, None)
        common_failures = None
        current_build = red_build
        build_after_current_build = None
        look_back_count = 0
        while current_build:
            if current_build.is_green():
                # current_build can't possibly have any failures in common
                # with red_build because it's green.
                break
            results = current_build.layout_test_results()
            # We treat a lack of results as if all the test failed.
            # This occurs, for example, when we can't compile at all.
            if results:
                failures = set(results.failing_tests())
                if common_failures == None:
                    common_failures = failures
                else:
                    common_failures = common_failures.intersection(failures)
                    if not common_failures:
                        # current_build doesn't have any failures in common with
                        # the red build we're worried about.  We assume that any
                        # failures in current_build were due to flakiness.
                        break
            look_back_count += 1
            if look_back_count > look_back_limit:
                return RegressionWindow(None, current_build, failing_tests=common_failures)
            build_after_current_build = current_build
            current_build = current_build.previous_build()
        # We must iterate at least once because red_build is red.
        assert(build_after_current_build)
        # Current build must either be green or have no failures in common
        # with red build, so we've found our failure transition.
        return RegressionWindow(current_build, build_after_current_build, failing_tests=common_failures)

    def find_blameworthy_regression_window(self, red_build_number, look_back_limit=30, avoid_flakey_tests=True):
        red_build = self.build(red_build_number)
        regression_window = self.find_regression_window(red_build, look_back_limit)
        if not regression_window.build_before_failure():
            return None  # We ran off the limit of our search
        # If avoid_flakey_tests, require at least 2 bad builds before we
        # suspect a real failure transition.
        if avoid_flakey_tests and regression_window.failing_build() == red_build:
            return None
        return regression_window


class Build(object):
    def __init__(self, builder, build_number, revision, is_green):
        self._builder = builder
        self._number = build_number
        self._revision = revision
        self._is_green = is_green
        self._layout_test_results = None

    @staticmethod
    def build_url(builder, build_number):
        return "%s/builds/%s" % (builder.url(), build_number)

    def url(self):
        return self.build_url(self.builder(), self._number)

    def results_url(self):
        results_directory = "r%s (%s)" % (self.revision(), self._number)
        return "%s/%s" % (self._builder.results_url(), urllib.quote(results_directory))

    def results_zip_url(self):
        return "%s.zip" % self.results_url()

    def _fetch_file_from_results(self, file_name):
        # It seems this can return None if the url redirects and then returns 404.
        result = urllib2.urlopen("%s/%s" % (self.results_url(), file_name))
        if not result:
            return None
        # urlopen returns a file-like object which sometimes works fine with str()
        # but sometimes is a addinfourl object.  In either case calling read() is correct.
        return result.read()

    def layout_test_results(self):
        if self._layout_test_results:
            return self._layout_test_results

        # FIXME: This should cache that the result was a 404 and stop hitting the network.
        results_file = NetworkTransaction(convert_404_to_None=True).run(lambda: self._fetch_file_from_results("full_results.json"))
        if not results_file:
            results_file = NetworkTransaction(convert_404_to_None=True).run(lambda: self._fetch_file_from_results("results.html"))

        # results_from_string accepts either ORWT html or NRWT json.
        self._layout_test_results = LayoutTestResults.results_from_string(results_file)
        return self._layout_test_results

    def builder(self):
        return self._builder

    def revision(self):
        return self._revision

    def is_green(self):
        return self._is_green

    def previous_build(self):
        # previous_build() allows callers to avoid assuming build numbers are sequential.
        # They may not be sequential across all master changes, or when non-trunk builds are made.
        return self._builder.build(self._number - 1)


class BuildBot(object):
    _builder_factory = Builder
    _default_url = config_urls.buildbot_url

    def __init__(self, url=None):
        self.buildbot_url = url if url else self._default_url
        self._builder_by_name = {}

        # If any core builder is red we should not be landing patches.  Other
        # builders should be added to this list once they are known to be
        # reliable.
        # See https://bugs.webkit.org/show_bug.cgi?id=33296 and related bugs.
        self.core_builder_names_regexps = [
            "SnowLeopard.*Build",
            "SnowLeopard.*\(Test",
            "SnowLeopard.*\(WebKit2 Test",
            "Leopard.*\((?:Build|Test)",
            "Windows.*Build",
            "Windows.*\(Test",
            "WinCairo",
            "WinCE",
            "EFL",
            "GTK.*32",
            "GTK.*64.*Debug",  # Disallow the 64-bit Release bot which is broken.
            "Qt",
            "Chromium.*Release$",
            "Chromium.*(Mac|Linux).*Release.*\(Tests",
        ]

    def _parse_last_build_cell(self, builder, cell):
        status_link = cell.find('a')
        if status_link:
            # Will be either a revision number or a build number
            revision_string = status_link.string
            # If revision_string has non-digits assume it's not a revision number.
            builder['built_revision'] = int(revision_string) \
                                        if not re.match('\D', revision_string) \
                                        else None

            # FIXME: We treat slave lost as green even though it is not to
            # work around the Qts bot being on a broken internet connection.
            # The real fix is https://bugs.webkit.org/show_bug.cgi?id=37099
            builder['is_green'] = not re.search('fail', cell.renderContents()) or \
                                  not not re.search('lost', cell.renderContents())

            status_link_regexp = r"builders/(?P<builder_name>.*)/builds/(?P<build_number>\d+)"
            link_match = re.match(status_link_regexp, status_link['href'])
            builder['build_number'] = int(link_match.group("build_number"))
        else:
            # We failed to find a link in the first cell, just give up.  This
            # can happen if a builder is just-added, the first cell will just
            # be "no build"
            # Other parts of the code depend on is_green being present.
            builder['is_green'] = False
            builder['built_revision'] = None
            builder['build_number'] = None

    def _parse_current_build_cell(self, builder, cell):
        activity_lines = cell.renderContents().split("<br />")
        builder["activity"] = activity_lines[0] # normally "building" or "idle"
        # The middle lines document how long left for any current builds.
        match = re.match("(?P<pending_builds>\d) pending", activity_lines[-1])
        builder["pending_builds"] = int(match.group("pending_builds")) if match else 0

    def _parse_builder_status_from_row(self, status_row):
        status_cells = status_row.findAll('td')
        builder = {}

        # First cell is the name
        name_link = status_cells[0].find('a')
        builder["name"] = unicode(name_link.string)

        self._parse_last_build_cell(builder, status_cells[1])
        self._parse_current_build_cell(builder, status_cells[2])
        return builder

    def _matches_regexps(self, builder_name, name_regexps):
        for name_regexp in name_regexps:
            if re.match(name_regexp, builder_name):
                return True
        return False

    # FIXME: Should move onto Builder
    def _is_core_builder(self, builder_name):
        return self._matches_regexps(builder_name, self.core_builder_names_regexps)

    # FIXME: This method needs to die, but is used by a unit test at the moment.
    def _builder_statuses_with_names_matching_regexps(self, builder_statuses, name_regexps):
        return [builder for builder in builder_statuses if self._matches_regexps(builder["name"], name_regexps)]

    def red_core_builders(self):
        return [builder for builder in self.core_builder_statuses() if not builder["is_green"]]

    def red_core_builders_names(self):
        return [builder["name"] for builder in self.red_core_builders()]

    def idle_red_core_builders(self):
        return [builder for builder in self.red_core_builders() if builder["activity"] == "idle"]

    def core_builders_are_green(self):
        return not self.red_core_builders()

    # FIXME: These _fetch methods should move to a networking class.
    def _fetch_build_dictionary(self, builder, build_number):
        # Note: filter=1 will remove None and {} and '', which cuts noise but can
        # cause keys to be missing which you might otherwise expect.
        # FIXME: The bot sends a *huge* amount of data for each request, we should
        # find a way to reduce the response size further.
        json_url = "%s/json/builders/%s/builds/%s?filter=1" % (self.buildbot_url, urllib.quote(builder.name()), build_number)
        try:
            return json.load(urllib2.urlopen(json_url))
        except urllib2.URLError, err:
            build_url = Build.build_url(builder, build_number)
            _log.error("Error fetching data for %s build %s (%s, json: %s): %s" % (builder.name(), build_number, build_url, json_url, err))
            return None
        except ValueError, err:
            build_url = Build.build_url(builder, build_number)
            _log.error("Error decoding json data from %s: %s" % (build_url, err))
            return None

    def _fetch_one_box_per_builder(self):
        build_status_url = "%s/one_box_per_builder" % self.buildbot_url
        return urllib2.urlopen(build_status_url)

    def _file_cell_text(self, file_cell):
        """Traverses down through firstChild elements until one containing a string is found, then returns that string"""
        element = file_cell
        while element.string is None and element.contents:
            element = element.contents[0]
        return element.string

    def _parse_twisted_file_row(self, file_row):
        string_or_empty = lambda string: unicode(string) if string else u""
        file_cells = file_row.findAll('td')
        return {
            "filename": string_or_empty(self._file_cell_text(file_cells[0])),
            "size": string_or_empty(self._file_cell_text(file_cells[1])),
            "type": string_or_empty(self._file_cell_text(file_cells[2])),
            "encoding": string_or_empty(self._file_cell_text(file_cells[3])),
        }

    def _parse_twisted_directory_listing(self, page):
        soup = BeautifulSoup(page)
        # HACK: Match only table rows with a class to ignore twisted header/footer rows.
        file_rows = soup.find('table').findAll('tr', {'class': re.compile(r'\b(?:directory|file)\b')})
        return [self._parse_twisted_file_row(file_row) for file_row in file_rows]

    # FIXME: There should be a better way to get this information directly from twisted.
    def _fetch_twisted_directory_listing(self, url):
        return self._parse_twisted_directory_listing(urllib2.urlopen(url))

    def builders(self):
        return [self.builder_with_name(status["name"]) for status in self.builder_statuses()]

    # This method pulls from /one_box_per_builder as an efficient way to get information about
    def builder_statuses(self):
        soup = BeautifulSoup(self._fetch_one_box_per_builder())
        return [self._parse_builder_status_from_row(status_row) for status_row in soup.find('table').findAll('tr')]

    def core_builder_statuses(self):
        return [builder for builder in self.builder_statuses() if self._is_core_builder(builder["name"])]

    def builder_with_name(self, name):
        builder = self._builder_by_name.get(name)
        if not builder:
            builder = self._builder_factory(name, self)
            self._builder_by_name[name] = builder
        return builder

    def failure_map(self, only_core_builders=True):
        builder_statuses = self.core_builder_statuses() if only_core_builders else self.builder_statuses()
        failure_map = FailureMap()
        revision_to_failing_bots = {}
        for builder_status in builder_statuses:
            if builder_status["is_green"]:
                continue
            builder = self.builder_with_name(builder_status["name"])
            regression_window = builder.find_blameworthy_regression_window(builder_status["build_number"])
            if regression_window:
                failure_map.add_regression_window(builder, regression_window)
        return failure_map

    # This makes fewer requests than calling Builder.latest_build would.  It grabs all builder
    # statuses in one request using self.builder_statuses (fetching /one_box_per_builder instead of builder pages).
    def _latest_builds_from_builders(self, only_core_builders=True):
        builder_statuses = self.core_builder_statuses() if only_core_builders else self.builder_statuses()
        return [self.builder_with_name(status["name"]).build(status["build_number"]) for status in builder_statuses]

    def _build_at_or_before_revision(self, build, revision):
        while build:
            if build.revision() <= revision:
                return build
            build = build.previous_build()

    def last_green_revision(self, only_core_builders=True):
        builds = self._latest_builds_from_builders(only_core_builders)
        target_revision = builds[0].revision()
        # An alternate way to do this would be to start at one revision and walk backwards
        # checking builder.build_for_revision, however build_for_revision is very slow on first load.
        while True:
            # Make builds agree on revision
            builds = [self._build_at_or_before_revision(build, target_revision) for build in builds]
            if None in builds: # One of the builds failed to load from the server.
                return None
            min_revision = min(map(lambda build: build.revision(), builds))
            if min_revision != target_revision:
                target_revision = min_revision
                continue # Builds don't all agree on revision, keep searching
            # Check to make sure they're all green
            all_are_green = reduce(operator.and_, map(lambda build: build.is_green(), builds))
            if not all_are_green:
                target_revision -= 1
                continue
            return min_revision
