#!/usr/bin/env python
"""
eslint.py
 Will download a prebuilt ESLint binary if necessary (i.e. it isn't installed, isn't in the current
 path, or is the wrong version). It works in much the same way as clang_format.py. In lint mode, it
 will lint the files or directory paths passed. In lint-patch mode, for upload.py, it will see if
 there are any candidate files in the supplied patch. Fix mode will run ESLint with the --fix
 option, and that will update the files with missing semicolons and similar repairable issues.
 There is also a -d mode that assumes you only want to run one copy of ESLint per file / directory
 parameter supplied. This lets ESLint search for candidate files to lint.
"""
import itertools
import os
import shutil
import string
import subprocess
import sys
import tarfile
import tempfile
import threading
import urllib
from distutils import spawn
from optparse import OptionParser

# Get relative imports to work when the package is not installed on the PYTHONPATH.
if __name__ == "__main__" and __package__ is None:
    sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(os.path.realpath(__file__)))))

from buildscripts.resmokelib.utils import globstar

from buildscripts.linter import git
from buildscripts.linter import parallel

##############################################################################
#
# Constants for ESLint
#
#

# Expected version of ESLint.
ESLINT_VERSION = "2.3.0"

# Name of ESLint as a binary.
ESLINT_PROGNAME = "eslint"

# URL location of our provided ESLint binaries.
ESLINT_HTTP_LINUX_CACHE = "https://s3.amazonaws.com/boxes.10gen.com/build/eslint-" + \
                           ESLINT_VERSION + "-linux.tar.gz"
ESLINT_HTTP_DARWIN_CACHE = "https://s3.amazonaws.com/boxes.10gen.com/build/eslint-" + \
                            ESLINT_VERSION + "-darwin.tar.gz"

# Path in the tarball to the ESLint binary.
ESLINT_SOURCE_TAR_BASE = string.Template(ESLINT_PROGNAME + "-$platform-$arch")

def callo(args):
    """Call a program, and capture its output
    """
    return subprocess.check_output(args)

def extract_eslint(tar_path, target_file):
    tarfp = tarfile.open(tar_path)
    for name in tarfp.getnames():
        if name == target_file:
            tarfp.extract(name)
    tarfp.close()

def get_eslint_from_cache(dest_file, platform, arch):
    """Get ESLint binary from mongodb's cache
    """
    # Get URL
    if platform == "Linux":
        url = ESLINT_HTTP_LINUX_CACHE
    elif platform == "Darwin":
        url = ESLINT_HTTP_DARWIN_CACHE
    else:
        raise ValueError('ESLint is not available as a binary for ' + platform)

    dest_dir = tempfile.gettempdir()
    temp_tar_file = os.path.join(dest_dir, "temp.tar.gz")

    # Download the file
    print("Downloading ESLint %s from %s, saving to %s" % (ESLINT_VERSION,
                                                           url, temp_tar_file))
    urllib.urlretrieve(url, temp_tar_file)

    eslint_distfile = ESLINT_SOURCE_TAR_BASE.substitute(platform=platform, arch=arch)
    extract_eslint(temp_tar_file, eslint_distfile)
    shutil.move(eslint_distfile, dest_file)


class ESLint(object):
    """Class encapsulates finding a suitable copy of ESLint, and linting an individual file
    """
    def __init__(self, path, cache_dir):
        eslint_progname = ESLINT_PROGNAME

        # Initialize ESLint configuration information
        if sys.platform.startswith("linux"):
            self.arch = "x86_64"
            self.tar_path = None
        elif sys.platform == "darwin":
            self.arch = "x86_64"
            self.tar_path = None

        self.path = None

        # Find ESLint now
        if path is not None:
            if os.path.isfile(path):
                self.path = path
            else:
                print("WARNING: Could not find ESLint at %s" % (path))

        # Check the environment variable
        if "MONGO_ESLINT" in os.environ:
            self.path = os.environ["MONGO_ESLINT"]

            if self.path and not self._validate_version(warn=True):
                self.path = None

        # Check the user's PATH environment variable now
        if self.path is None:
            self.path = spawn.find_executable(eslint_progname)

            if self.path and not self._validate_version(warn=True):
                self.path = None

        # Have not found it yet, download it from the web
        if self.path is None:
            if not os.path.isdir(cache_dir):
                os.makedirs(cache_dir)

            self.path = os.path.join(cache_dir, eslint_progname)

            if not os.path.isfile(self.path):
                if sys.platform.startswith("linux"):
                    get_eslint_from_cache(self.path, "Linux", self.arch)
                elif sys.platform == "darwin":
                    get_eslint_from_cache(self.path, "Darwin", self.arch)
                else:
                    print("ERROR: eslint.py does not support downloading ESLint " +
                          "on this platform, please install ESLint " + ESLINT_VERSION)
        # Validate we have the correct version
        if not self._validate_version():
            raise ValueError('correct version of ESLint was not found.')

        self.print_lock = threading.Lock()

    def _validate_version(self, warn=False):
        """Validate ESLint is the expected version
        """
        esl_version = callo([self.path, "--version"]).rstrip()
        # Ignore the leading v in the version string.
        if ESLINT_VERSION == esl_version[1:]:
            return True

        if warn:
            print("WARNING: eslint found in path, but incorrect version found at " +
                  self.path + " with version: " + esl_version)
        return False

    def _lint(self, file_name, print_diff):
        """Check the specified file for linting errors
        """
        # ESLint returns non-zero on a linting error. That's all we care about
        # so only enter the printing logic if we have an error.
        try:
            eslint_output = callo([self.path, "-f", "unix", file_name])
        except subprocess.CalledProcessError as e:
            if print_diff:
                # Take a lock to ensure error messages do not get mixed when printed to the screen
                with self.print_lock:
                    print("ERROR: ESLint found errors in " + file_name)
                    print(e.output)
            return False
        except:
            print("ERROR: ESLint process threw unexpected error", sys.exc_info()[0])
            return False

        return True

    def lint(self, file_name):
        """Check the specified file has no linting errors
        """
        return self._lint(file_name, print_diff=True)

    def autofix(self, file_name):
        """ Run ESLint in fix mode.
        """
        return not subprocess.call([self.path, "--fix", file_name])

def is_interesting_file(file_name):
    """"Return true if this file should be checked
    """
    return ((file_name.startswith("src/mongo") or file_name.startswith("jstests"))
            and file_name.endswith(".js"))

def _get_build_dir():
    """Get the location of the scons build directory in case we need to download ESLint
    """
    return os.path.join(git.get_base_dir(), "build")

def _lint_files(eslint, files):
    """Lint a list of files with ESLint
    """
    eslint = ESLint(eslint, _get_build_dir())

    lint_clean = parallel.parallel_process([os.path.abspath(f) for f in files], eslint.lint)

    if not lint_clean:
        print("ERROR: ESLint found errors. Run ESLint manually to see errors in "\
              "files that were skipped")
        sys.exit(1)

    return True

def lint_patch(eslint, infile):
    """Lint patch command entry point
    """
    files = git.get_files_to_check_from_patch(infile, is_interesting_file)

    # Patch may have files that we do not want to check which is fine
    if files:
        return _lint_files(eslint, files)
    return True

def lint(eslint, dirmode, glob):
    """Lint files command entry point
    """
    if dirmode and glob:
        files = glob
    else:
        files = get_files_to_check(glob, is_interesting_file)

    _lint_files(eslint, files)

    return True

def _autofix_files(eslint, files):
    """Auto-fix the specified files with ESLint.
    """
    eslint = ESLint(eslint, _get_build_dir())

    autofix_clean = parallel.parallel_process([os.path.abspath(f) for f in files], eslint.autofix)

    if not autofix_clean:
        print("ERROR: failed to auto-fix files")
        return False

def autofix_func(eslint, dirmode, glob):
    """Auto-fix files command entry point
    """
    if dirmode:
        files = glob
    else:
        files = get_files_to_check(glob, is_interesting_file)

    return _autofix_files(eslint, files)


def main():
    """Main entry point
    """
    success = False
    usage = "%prog [-e <eslint>] [-d] lint|lint-patch|fix [glob patterns] "
    description = "lint runs ESLint on provided patterns or all .js files under jstests/ "\
                  "and src/mongo. lint-patch runs ESLint against .js files modified in the "\
                  "provided patch file (for upload.py). "\
                  "fix runs ESLint with --fix on provided patterns "\
                  "or files under jstests/ and src/mongo."
    epilog ="*Unless you specify -d a separate ESLint process will be launched for every file"
    parser = OptionParser()
    parser = OptionParser(usage=usage, description=description, epilog=epilog)
    parser.add_option("-e", "--eslint", type="string", dest="eslint",
                      help="Fully qualified path to eslint executable",)
    parser.add_option("-d", "--dirmode", action="store_true", default=True, dest="dirmode",
                      help="Considers the glob patterns as directories and runs ESLint process " \
                           "against each pattern",)

    (options, args) = parser.parse_args(args=sys.argv)

    if len(args) > 1:
        command = args[1]
        searchlist = args[2:]
        if not searchlist:
            searchlist = ["jstests/", "src/mongo/"]

        if command == "lint":
            success = lint(options.eslint, options.dirmode, searchlist)
        elif command == "lint-patch":
            if not args[2:]:
                success = False
                print("You must provide the patch's fully qualified file name with lint-patch")
            else:
                success = lint_patch(options.eslint, searchlist)
        elif command == "fix":
            success = autofix_func(options.eslint, options.dirmode, searchlist)
        else:
            parser.print_help()
    else:
        parser.print_help()

    sys.exit(0 if success else 1)
if __name__ == "__main__":
    main()
