#!/usr/bin/env python
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

# Script which checks Java API compatibility between two revisions of the
# Java client.
#
# Originally sourced from Apache Kudu, which was based on the
# compatibility checker from the Apache HBase project, but ported to
# Python for better readability.

# The script can be invoked as follows:
#   $ ./checkcompatibility.py ${SOURCE_GIT_REVISION} ${GIT_BRANCH_OR_TAG}
# or with some options:
#   $ ./dev-support/checkcompatibility.py \
#      --annotation org.apache.hadoop.hbase.classification.InterfaceAudience.Public \
#      --annotation org.apache.hadoop.hbase.classification.InterfaceAudience.LimitedPrivate \
#      --include-file "hbase-*" \
#      --known_problems_path ~/known_problems.json \
#      rel/1.0.0 branch-1.2

import json
import logging
import os
import re
import shutil
import subprocess
import sys
import urllib2
from collections import namedtuple
try:
    import argparse
except ImportError:
    logging.error(
        "Please install argparse, e.g. via `pip install argparse`.")
    sys.exit(2)

# Various relative paths
REPO_DIR = os.getcwd()


def check_output(*popenargs, **kwargs):
    """ Run command with arguments and return its output as a byte string.
    Backported from Python 2.7 as it's implemented as pure python on stdlib.
    >>> check_output(['/usr/bin/python', '--version'])
    Python 2.6.2 """
    process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
    output, _ = process.communicate()
    retcode = process.poll()
    if retcode:
        cmd = kwargs.get("args")
        if cmd is None:
            cmd = popenargs[0]
        error = subprocess.CalledProcessError(retcode, cmd)
        error.output = output
        raise error
    return output


def get_repo_dir():
    """ Return the path to the top of the repo. """
    dirname, _ = os.path.split(os.path.abspath(__file__))
    dirname = os.path.dirname(dirname)
    logging.debug("Repo dir is  %s", dirname)
    return dirname


def get_scratch_dir():
    """ Return the path to the scratch dir that we build within. """
    scratch_dir = os.path.join(get_repo_dir(), "target", "compat-check")
    if not os.path.exists(scratch_dir):
        os.makedirs(scratch_dir)
    return scratch_dir


def get_java_acc_dir():
    """ Return the path where we check out the Java API Compliance Checker. """
    return os.path.join(get_repo_dir(), "target", "java-acc")


def clean_scratch_dir(scratch_dir):
    """ Clean up and re-create the scratch directory. """
    if os.path.exists(scratch_dir):
        logging.info("Removing scratch dir %s ", scratch_dir)
        shutil.rmtree(scratch_dir)
    logging.info("Creating empty scratch dir %s ", scratch_dir)
    os.makedirs(scratch_dir)


def checkout_java_tree(rev, path):
    """ Check out the Java source tree for the given revision into
    the given path. """
    logging.info("Checking out %s in %s", rev, path)
    os.makedirs(path)
    # Extract java source
    subprocess.check_call(["bash", '-o', 'pipefail', "-c",
                           ("git archive --format=tar %s | "
                            "tar -C '%s' -xf -") % (rev, path)],
                          cwd=get_repo_dir())


def get_git_hash(revname):
    """ Convert 'revname' to its SHA-1 hash. """
    try:
        return check_output(["git", "rev-parse", revname],
                        cwd=get_repo_dir()).strip()
    except:
        revname = "origin/" + revname
        return check_output(["git", "rev-parse", revname],
                        cwd=get_repo_dir()).strip()


def get_repo_name(remote_name="origin"):
    """ Get the name of the repo based on the git remote."""
    remote = check_output(["git", "config", "--get", "remote.{0}.url".format(remote_name)],
                           cwd=get_repo_dir()).strip()
    remote = remote.split("/")[-1]
    return remote[:-4] if remote.endswith(".git") else remote


def build_tree(java_path, verbose):
    """ Run the Java build within 'path'. """
    logging.info("Building in %s ", java_path)
    mvn_cmd = ["mvn", "--batch-mode", "-DskipTests",
               "-Dmaven.javadoc.skip=true", "package"]
    if not verbose:
        mvn_cmd.insert(-1, "--quiet")
    subprocess.check_call(mvn_cmd, cwd=java_path)


def checkout_java_acc(force):
    """ Check out the Java API Compliance Checker. If 'force' is true, will
    re-download even if the directory exists. """
    acc_dir = get_java_acc_dir()
    if os.path.exists(acc_dir):
        logging.info("Java ACC is already downloaded.")
        if not force:
            return
        logging.info("Forcing re-download.")
        shutil.rmtree(acc_dir)

    logging.info("Downloading Java ACC...")

    url = "https://github.com/lvc/japi-compliance-checker/archive/2.4.tar.gz"
    scratch_dir = get_scratch_dir()
    path = os.path.join(scratch_dir, os.path.basename(url))
    jacc = urllib2.urlopen(url)
    with open(path, 'wb') as w:
        w.write(jacc.read())

    subprocess.check_call(["tar", "xzf", path],
                          cwd=scratch_dir)

    shutil.move(os.path.join(scratch_dir, "japi-compliance-checker-2.4"),
                os.path.join(acc_dir))


def find_jars(path):
    """ Return a list of jars within 'path' to be checked for compatibility. """
    all_jars = set(check_output(["find", path, "-name", "*.jar"]).splitlines())

    return [j for j in all_jars if (
        "-tests" not in j and
        "-sources" not in j and
        "-with-dependencies" not in j)]


def write_xml_file(path, version, jars):
    """ Write the XML manifest file for JACC. """
    with open(path, "wt") as f:
        f.write("<version>%s</version>\n" % version)
        f.write("<archives>")
        for j in jars:
            f.write("%s\n" % j)
        f.write("</archives>")


def ascii_encode_dict(data):
    """ Iterate through a dictionary of data and convert all unicode to ascii.
    This method was taken from
    stackoverflow.com/questions/9590382/forcing-python-json-module-to-work-with-ascii """
    ascii_encode = lambda x: x.encode('ascii') if isinstance(x, unicode) else x
    return dict(map(ascii_encode, pair) for pair in data.items())


def process_json(path):
    """ Process the known problems json file. The program raises an uncaught exception
    if it can't find the file or if the json is invalid """
    path = os.path.abspath(os.path.expanduser(path))
    try:
        with open(path) as f:
            return json.load(f, object_hook=ascii_encode_dict)
    except ValueError as e:
        logging.error("File: %s\nInvalid JSON:\n%s", str(path), str(e))
        raise
    except IOError as io:
        logging.error("Provided json file path does not exist %s", str(path))
        raise


def compare_results(tool_results, known_issues, compare_warnings):
    """ Compare the number of problems found with the allowed number. If
    compare_warnings is true then also compare the number of warnings found.

    tool_results = results from the JACC tool - a dictionary
    known_issues = dictionary of expected issue count
    compare_warnings = boolean - if true also compare warnings as well as problems """
    logging.info("Results: %s", str(tool_results))

    unexpected_issue = namedtuple('unexpected_issue', ['check', 'issue_type',
                                                        'known_count', 'observed_count'])
    unexpected_issues = [unexpected_issue(check=check,  issue_type=issue_type,
                                      known_count=known_count,
                                      observed_count=tool_results[check][issue_type])
                     for check, known_issue_counts in known_issues.items()
                        for issue_type, known_count in known_issue_counts.items()
                            if tool_results[check][issue_type] > known_count]

    if not compare_warnings:
        unexpected_issues = [tup for tup in unexpected_issues
                             if tup.issue_type != 'warnings']

    for issue in unexpected_issues:
        logging.error('Found %s during  %s check (known issues: %d, observed issues: %d)',
                issue.issue_type, issue.check, issue.known_count, issue.observed_count)

    return bool(unexpected_issues)


def process_java_acc_output(output):
    """ Process the output string to find the problems and warnings in both the
    binary and source compatibility. This is done in a way that is admittedly
    brittle; we are open to better implementations.

    We expect a line containing the relevant information to look something like:
    "total binary compatibility problems: 123, warnings: 16" """
    return_value = {}
    output = output.split("\n")
    for line in output:
        # Line has relevant info
        if line.lower().startswith("total"):
            values = {}
            # Remove "total" keyword
            line = line[6:]
            # Seperate the two valuable parts
            line_list = line.split(",")
            for segment in line_list:
                part = segment.split(":")
                # Extract key and value
                values[part[0][-8:]] = int(part[1])
            return_value[line[:6]] = values
    return return_value

def log_java_acc_version():
    java_acc_path = os.path.join(
        get_java_acc_dir(), "japi-compliance-checker.pl")

    args = ["perl", java_acc_path, "-version"]
    logging.info(check_output(args))

def run_java_acc(src_name, src_jars, dst_name, dst_jars, annotations, skip_annotations, name):
    """ Run the compliance checker to compare 'src' and 'dst'. """
    logging.info("Will check compatibility between original jars:\n\t%s\n"
                 "and new jars:\n\t%s",
                 "\n\t".join(src_jars),
                 "\n\t".join(dst_jars))

    java_acc_path = os.path.join(
        get_java_acc_dir(), "japi-compliance-checker.pl")

    src_xml_path = os.path.join(get_scratch_dir(), "src.xml")
    dst_xml_path = os.path.join(get_scratch_dir(), "dst.xml")
    write_xml_file(src_xml_path, src_name, src_jars)
    write_xml_file(dst_xml_path, dst_name, dst_jars)

    out_path = os.path.join(get_scratch_dir(), "report.html")

    args = ["perl", java_acc_path,
            "-l", name,
            "-d1", src_xml_path,
            "-d2", dst_xml_path,
            "-report-path", out_path]
    if annotations is not None:
        logging.info("Annotations are: %s", annotations)
        annotations_path = os.path.join(get_scratch_dir(), "annotations.txt")
        logging.info("Annotations path: %s", annotations_path)
        with file(annotations_path, "w") as f:
            f.write('\n'.join(annotations))
        args.extend(["-annotations-list", annotations_path])

    if skip_annotations is not None:
        skip_annotations_path = os.path.join(
            get_scratch_dir(), "skip_annotations.txt")
        with file(skip_annotations_path, "w") as f:
            f.write('\n'.join(skip_annotations))
        args.extend(["-skip-annotations-list", skip_annotations_path])

    try:
        output = check_output(args)
    except subprocess.CalledProcessError as e:
        # The program returns a nonzero error code if issues are found. We
        # almost always expect some issues and want to process the results.
        output = e.output
    acc_processed = process_java_acc_output(output)
    return acc_processed


def get_known_problems(json_path, src_rev, dst_rev):
    """ The json file should be in the following format: a dictionary with the
    keys in the format source_branch/destination_branch and the values
    dictionaries with binary and source problems and warnings
    Example:
    {'branch-1.0.0': {
      'rel/1.0.0': {'binary': {'problems': 123, 'warnings': 16},
                      'source': {'problems': 167, 'warnings': 1}},
      'branch-1.2.0': {'binary': {'problems': 0, 'warnings': 0},
                      'source': {'problems': 0, 'warnings': 0}}
      },
    'branch-1.2.0': {
      'rel/1.2.1': {'binary': {'problems': 13, 'warnings': 1},
                      'source': {'problems': 23, 'warnings': 0}}
      }
    } """
    # These are the default values for allowed problems and warnings
    known_problems = {"binary": {"problems": 0, "warnings": 0},
                           "source": {"problems": 0, "warnings": 0}}
    if src_rev.startswith("origin/"):
      src_rev = src_rev[7:]
    if dst_rev.startswith("origin/"):
      dst_rev = dst_rev[7:]
    if json_path is not None:
        known_problems = process_json(json_path)
        try:
            return known_problems[src_rev][dst_rev]
        except KeyError:
            logging.error(("Known Problems values for %s %s are not in "
                            "provided json file. If you are trying to run "
                            "the test with the default values, don't "
                            "provide the --known_problems_path argument")
                            % (src_rev, dst_rev))
            raise
    return known_problems


def filter_jars(jars, include_filters, exclude_filters):
    """ Filter the list of JARs based on include and exclude filters. """
    filtered = []
    # Apply include filters
    for j in jars:
        basename = os.path.basename(j)
        for f in include_filters:
            if f.match(basename):
                filtered += [j]
                break
        else:
            logging.debug("Ignoring JAR %s", j)
    # Apply exclude filters
    exclude_filtered = []
    for j in filtered:
        basename = os.path.basename(j)
        for f in exclude_filters:
            if f.match(basename):
                logging.debug("Ignoring JAR %s", j)
                break
        else:
            exclude_filtered += [j]

    return exclude_filtered


def main():
    """ Main function. """
    logging.basicConfig(level=logging.INFO)
    parser = argparse.ArgumentParser(
        description="Run Java API Compliance Checker.")
    parser.add_argument("-f", "--force-download",
                        action="store_true",
                        help="Download dependencies (i.e. Java JAVA_ACC) "
                        "even if they are already present")
    parser.add_argument("-i", "--include-file",
                        action="append",
                        dest="include_files",
                        help="Regex filter for JAR files to be included. "
                        "Applied before the exclude filters. "
                        "Can be specified multiple times.")
    parser.add_argument("-e", "--exclude-file",
                        action="append",
                        dest="exclude_files",
                        help="Regex filter for JAR files to be excluded. "
                        "Applied after the include filters. "
                        "Can be specified multiple times.")
    parser.add_argument("-a", "--annotation",
                        action="append",
                        dest="annotations",
                        help="Fully-qualified Java annotation. "
                        "Java ACC will only check compatibility of "
                        "annotated classes. Can be specified multiple times.")
    parser.add_argument("--skip-annotation",
                        action="append",
                        dest="skip_annotations",
                        help="Fully-qualified Java annotation. "
                        "Java ACC will not check compatibility of "
                        "these annotated classes. Can be specified multiple "
                        "times.")
    parser.add_argument("-p", "--known_problems_path",
                        default=None, dest="known_problems_path",
                        help="Path to file with json 'known_problems "
                        "dictionary.' Path can be relative or absolute. An "
                        "examples file can be seen in the pydocs for the "
                        "get_known_problems method.")
    parser.add_argument("--skip-clean",
                        action="store_true",
                        help="Skip cleaning the scratch directory.")
    parser.add_argument("--compare-warnings", dest="compare_warnings",
                        action="store_true", default=False,
                        help="Compare warnings as well as problems.")
    parser.add_argument("--skip-build",
                        action="store_true",
                        help="Skip building the projects.")
    parser.add_argument("--verbose",
                        action="store_true",
                        help="more output")
    parser.add_argument("-r", "--remote", default="origin", dest="remote_name",
                        help="Name of remote to use. e.g. its repo name will be used as the name "
                        "we pass to Java ACC for the library.")
    parser.add_argument("src_rev", nargs=1, help="Source revision.")
    parser.add_argument("dst_rev", nargs="?", default="HEAD",
                        help="Destination revision. "
                        "If not specified, will use HEAD.")

    args = parser.parse_args()

    src_rev, dst_rev = args.src_rev[0], args.dst_rev

    logging.info("Source revision: %s", src_rev)
    logging.info("Destination revision: %s", dst_rev)

    # Configure the expected numbers
    known_problems = get_known_problems(
        args.known_problems_path, src_rev, dst_rev)

    # Construct the JAR regex patterns for filtering.
    include_filters = []
    if args.include_files is not None:
        for f in args.include_files:
            logging.info("Applying JAR filename include filter: %s", f)
            include_filters += [re.compile(f)]
    else:
        include_filters = [re.compile(".*")]

    exclude_filters = []
    if args.exclude_files is not None:
        for f in args.exclude_files:
            logging.info("Applying JAR filename exclude filter: %s", f)
            exclude_filters += [re.compile(f)]

    # Construct the annotation list
    if args.annotations is not None:
        logging.info("Filtering classes using %d annotation(s):",
                     len(args.annotations))
        for a in args.annotations:
            logging.info("\t%s", a)

    skip_annotations = args.skip_annotations
    if skip_annotations is not None:
        logging.info("Skipping classes with %d annotation(s):",
                     len(skip_annotations))
        for a in skip_annotations:
            logging.info("\t%s", a)

    # Download deps.
    checkout_java_acc(args.force_download)
    log_java_acc_version()

    # Set up the build.
    scratch_dir = get_scratch_dir()
    src_dir = os.path.join(scratch_dir, "src")
    dst_dir = os.path.join(scratch_dir, "dst")

    if args.skip_clean:
        logging.info("Skipping cleaning the scratch directory")
    else:
        clean_scratch_dir(scratch_dir)
        # Check out the src and dst source trees.
        checkout_java_tree(get_git_hash(src_rev), src_dir)
        checkout_java_tree(get_git_hash(dst_rev), dst_dir)

    # Run the build in each.
    if args.skip_build:
        logging.info("Skipping the build")
    else:
        build_tree(src_dir, args.verbose)
        build_tree(dst_dir, args.verbose)

    # Find the JARs.
    src_jars = find_jars(src_dir)
    dst_jars = find_jars(dst_dir)

    # Filter the JARs.
    src_jars = filter_jars(src_jars, include_filters, exclude_filters)
    dst_jars = filter_jars(dst_jars, include_filters, exclude_filters)

    if not src_jars or not dst_jars:
        logging.error("No JARs found! Are your filters too strong?")
        sys.exit(1)

    output = run_java_acc(src_rev, src_jars, dst_rev,
                            dst_jars, args.annotations, skip_annotations,
                            get_repo_name(args.remote_name))
    sys.exit(compare_results(output, known_problems,
                              args.compare_warnings))


if __name__ == "__main__":
    main()