# -*- coding: utf-8 -*-
from __future__ import unicode_literals, absolute_import
from collections import OrderedDict
import re
import yaml

from io import StringIO

from six.moves.configparser import SafeConfigParser, NoOptionError


from .regex import URL_REGEX, HASH_REGEX

from .dependencies import DependencyFile, Dependency
from packaging.requirements import Requirement as PackagingRequirement, InvalidRequirement
from . import filetypes
import toml
from packaging.specifiers import SpecifierSet
import json


# this is a backport from setuptools 26.1
def setuptools_parse_requirements_backport(strs):  # pragma: no cover
    # Copyright (C) 2016 Jason R Coombs <jaraco@jaraco.com>
    #
    # Permission is hereby granted, free of charge, to any person obtaining a copy of
    # this software and associated documentation files (the "Software"), to deal in
    # the Software without restriction, including without limitation the rights to
    # use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
    # of the Software, and to permit persons to whom the Software is furnished to do
    # so, subject to the following conditions:
    #
    # The above copyright notice and this permission notice shall be included in all
    # copies or substantial portions of the Software.
    #
    # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    # SOFTWARE.
    """Yield ``Requirement`` objects for each specification in `strs`

    `strs` must be a string, or a (possibly-nested) iterable thereof.
    """
    # create a steppable iterator, so we can handle \-continuations
    def yield_lines(strs):
        """Yield non-empty/non-comment lines of a string or sequence"""
        if isinstance(strs, str):
            for s in strs.splitlines():
                s = s.strip()
                # skip blank lines/comments
                if s and not s.startswith('#'):
                    yield s
        else:
            for ss in strs:
                for s in yield_lines(ss):
                    yield s
    lines = iter(yield_lines(strs))

    for line in lines:
        # Drop comments -- a hash without a space may be in a URL.
        if ' #' in line:
            line = line[:line.find(' #')]
        # If there is a line continuation, drop it, and append the next line.
        if line.endswith('\\'):
            line = line[:-2].strip()
            line += next(lines)
        yield PackagingRequirement(line)


class RequirementsTXTLineParser(object):
    """

    """

    @classmethod
    def parse(cls, line):
        """

        :param line:
        :return:
        """
        try:
            # setuptools requires a space before the comment. If this isn't the case, add it.
            if "\t#" in line:
                parsed, = setuptools_parse_requirements_backport(line.replace("\t#", "\t #"))
            else:
                parsed, = setuptools_parse_requirements_backport(line)
        except InvalidRequirement:
            return None
        dep = Dependency(
            name=parsed.name,
            specs=parsed.specifier,
            line=line,
            extras=parsed.extras,
            dependency_type=filetypes.requirements_txt
        )
        return dep


class Parser(object):
    """

    """

    def __init__(self, obj):
        """

        :param obj:
        """
        self.obj = obj
        self._lines = None

    def iter_lines(self, lineno=0):
        """

        :param lineno:
        :return:
        """
        for line in self.lines[lineno:]:
            yield line

    @property
    def lines(self):
        """

        :return:
        """
        if self._lines is None:
            self._lines = self.obj.content.splitlines()
        return self._lines

    @property
    def is_marked_file(self):
        """

        :return:
        """
        for n, line in enumerate(self.iter_lines()):
            for marker in self.obj.file_marker:
                if marker in line:
                    return True
            if n >= 2:
                break
        return False

    def is_marked_line(self, line):
        """

        :param line:
        :return:
        """
        for marker in self.obj.line_marker:
            if marker in line:
                return True
        return False

    @classmethod
    def parse_hashes(cls, line):
        """

        :param line:
        :return:
        """
        hashes = []
        for match in re.finditer(HASH_REGEX, line):
            hashes.append(line[match.start():match.end()])
        return re.sub(HASH_REGEX, "", line).strip(), hashes

    @classmethod
    def parse_index_server(cls, line):
        """

        :param line:
        :return:
        """
        matches = URL_REGEX.findall(line)
        if matches:
            url = matches[0]
            return url if url.endswith("/") else url + "/"
        return None

    @classmethod
    def resolve_file(cls, file_path, line):
        """

        :param file_path:
        :param line:
        :return:
        """
        line = line.replace("-r ", "").replace("--requirement ", "")
        parts = file_path.split("/")
        if " #" in line:
            line = line.split("#")[0].strip()
        if len(parts) == 1:
            return line
        return "/".join(parts[:-1]) + "/" + line


class RequirementsTXTParser(Parser):
    """

    """

    def parse(self):
        """
        Parses a requirements.txt-like file
        """
        index_server = None
        for num, line in enumerate(self.iter_lines()):
            line = line.rstrip()
            if not line:
                continue
            if line.startswith('#'):
                # comments are lines that start with # only
                continue
            if line.startswith('-i') or \
                line.startswith('--index-url') or \
                line.startswith('--extra-index-url'):
                # this file is using a private index server, try to parse it
                index_server = self.parse_index_server(line)
                continue
            elif self.obj.path and (line.startswith('-r') or line.startswith('--requirement')):
                self.obj.resolved_files.append(self.resolve_file(self.obj.path, line))
            elif line.startswith('-f') or line.startswith('--find-links') or \
                line.startswith('--no-index') or line.startswith('--allow-external') or \
                line.startswith('--allow-unverified') or line.startswith('-Z') or \
                line.startswith('--always-unzip'):
                continue
            elif self.is_marked_line(line):
                continue
            else:
                try:

                    parseable_line = line

                    # multiline requirements are not parseable
                    if "\\" in line:
                        parseable_line = line.replace("\\", "")
                        for next_line in self.iter_lines(num + 1):
                            parseable_line += next_line.strip().replace("\\", "")
                            line += "\n" + next_line
                            if "\\" in next_line:
                                continue
                            break
                        # ignore multiline requirements if they are marked
                        if self.is_marked_line(parseable_line):
                            continue

                    hashes = []
                    if "--hash" in parseable_line:
                        parseable_line, hashes = Parser.parse_hashes(parseable_line)

                    req = RequirementsTXTLineParser.parse(parseable_line)
                    if req:
                        req.hashes = hashes
                        req.index_server = index_server
                        # replace the requirements line with the 'real' line
                        req.line = line
                        self.obj.dependencies.append(req)
                except ValueError:
                    continue


class ToxINIParser(Parser):
    """

    """

    def parse(self):
        """

        :return:
        """
        parser = SafeConfigParser()
        parser.readfp(StringIO(self.obj.content))
        for section in parser.sections():
            try:
                content = parser.get(section=section, option="deps")
                for n, line in enumerate(content.splitlines()):
                    if self.is_marked_line(line):
                        continue
                    if line:
                        req = RequirementsTXTLineParser.parse(line)
                        if req:
                            req.dependency_type = self.obj.file_type
                            self.obj.dependencies.append(req)
            except NoOptionError:
                pass


class CondaYMLParser(Parser):
    """

    """

    def parse(self):
        """

        :return:
        """
        try:
            data = yaml.safe_load(self.obj.content)
            if data and 'dependencies' in data and isinstance(data['dependencies'], list):
                for dep in data['dependencies']:
                    if isinstance(dep, dict) and 'pip' in dep:
                        for n, line in enumerate(dep['pip']):
                            if self.is_marked_line(line):
                                continue
                            req = RequirementsTXTLineParser.parse(line)
                            if req:
                                req.dependency_type = self.obj.file_type
                                self.obj.dependencies.append(req)
        except yaml.YAMLError:
            pass


class PipfileParser(Parser):

    def parse(self):
        """
        Parse a Pipfile (as seen in pipenv)
        :return:
        """
        try:
            data = toml.loads(self.obj.content, _dict=OrderedDict)
            if data:
                for package_type in ['packages', 'dev-packages']:
                    if package_type in data:
                        for name, specs in data[package_type].items():
                            # skip on VCS dependencies
                            if not isinstance(specs, str):
                                continue
                            if specs == '*':
                                specs = ''
                            self.obj.dependencies.append(
                                Dependency(
                                    name=name, specs=SpecifierSet(specs),
                                    dependency_type=filetypes.pipfile,
                                    line=''.join([name, specs]),
                                    section=package_type
                                )
                            )
        except (toml.TomlDecodeError, IndexError) as e:
            pass

class PipfileLockParser(Parser):

    def parse(self):
        """
        Parse a Pipfile.lock (as seen in pipenv)
        :return:
        """
        try:
            data = json.loads(self.obj.content, object_pairs_hook=OrderedDict)
            if data:
                for package_type in ['default', 'develop']:
                    if package_type in data:
                        for name, meta in data[package_type].items():
                            # skip VCS dependencies
                            if 'version' not in meta:
                                continue
                            specs = meta['version']
                            hashes = meta['hashes']
                            self.obj.dependencies.append(
                                Dependency(
                                    name=name, specs=SpecifierSet(specs),
                                    dependency_type=filetypes.pipfile_lock,
                                    hashes=hashes,
                                    line=''.join([name, specs]),
                                    section=package_type
                                )
                            )
        except ValueError:
            pass


class SetupCfgParser(Parser):
    def parse(self):
        parser = SafeConfigParser()
        parser.readfp(StringIO(self.obj.content))
        for section in parser.values():
            if section.name == 'options':
                options = 'install_requires', 'setup_requires', 'test_require'
                for name in options:
                    content = section.get(name)
                    if not content:
                        continue
                    self._parse_content(content)
            elif section.name == 'options.extras_require':
                for content in section.values():
                    self._parse_content(content)

    def _parse_content(self, content):
        for n, line in enumerate(content.splitlines()):
            if self.is_marked_line(line):
                continue
            if line:
                req = RequirementsTXTLineParser.parse(line)
                if req:
                    req.dependency_type = self.obj.file_type
                    self.obj.dependencies.append(req)


def parse(content, file_type=None, path=None, sha=None, marker=((), ()), parser=None):
    """

    :param content:
    :param file_type:
    :param path:
    :param sha:
    :param marker:
    :param parser:
    :return:
    """
    dep_file = DependencyFile(
        content=content,
        path=path,
        sha=sha,
        marker=marker,
        file_type=file_type,
        parser=parser
    )

    return dep_file.parse()
