"""Utilities to find and read config files used by packaging."""

import os
import sys
import logging

from shlex import split
from configparser import RawConfigParser
from packaging import logger
from packaging.errors import PackagingOptionError
from packaging.compiler.extension import Extension
from packaging.util import (check_environ, iglob, resolve_name, strtobool,
                            split_multiline)
from packaging.compiler import set_compiler
from packaging.command import set_command
from packaging.markers import interpret


def _check_name(name, packages):
    if '.' not in name:
        return
    parts = name.split('.')
    modname = parts[-1]
    parent = '.'.join(parts[:-1])
    if parent not in packages:
        # we could log a warning instead of raising, but what's the use
        # of letting people build modules they can't import?
        raise PackagingOptionError(
            'parent package for extension %r not found' % name)


def _pop_values(values_dct, key):
    """Remove values from the dictionary and convert them as a list"""
    vals_str = values_dct.pop(key, '')
    if not vals_str:
        return
    fields = []
    # the line separator is \n for setup.cfg files
    for field in vals_str.split('\n'):
        tmp_vals = field.split('--')
        if len(tmp_vals) == 2 and not interpret(tmp_vals[1]):
            continue
        fields.append(tmp_vals[0])
    # Get bash options like `gcc -print-file-name=libgcc.a` XXX bash options?
    vals = split(' '.join(fields))
    if vals:
        return vals


def _rel_path(base, path):
    # normalizes and returns a lstripped-/-separated path
    base = base.replace(os.path.sep, '/')
    path = path.replace(os.path.sep, '/')
    assert path.startswith(base)
    return path[len(base):].lstrip('/')


def get_resources_dests(resources_root, rules):
    """Find destinations for resources files"""
    destinations = {}
    for base, suffix, dest in rules:
        prefix = os.path.join(resources_root, base)
        for abs_base in iglob(prefix):
            abs_glob = os.path.join(abs_base, suffix)
            for abs_path in iglob(abs_glob):
                resource_file = _rel_path(resources_root, abs_path)
                if dest is None:  # remove the entry if it was here
                    destinations.pop(resource_file, None)
                else:
                    rel_path = _rel_path(abs_base, abs_path)
                    rel_dest = dest.replace(os.path.sep, '/').rstrip('/')
                    destinations[resource_file] = rel_dest + '/' + rel_path
    return destinations


class Config:
    """Class used to work with configuration files"""
    def __init__(self, dist):
        self.dist = dist
        self.setup_hooks = []

    def run_hooks(self, config):
        """Run setup hooks in the order defined in the spec."""
        for hook in self.setup_hooks:
            hook(config)

    def find_config_files(self):
        """Find as many configuration files as should be processed for this
        platform, and return a list of filenames in the order in which they
        should be parsed.  The filenames returned are guaranteed to exist
        (modulo nasty race conditions).

        There are three possible config files: packaging.cfg in the
        Packaging installation directory (ie. where the top-level
        Packaging __inst__.py file lives), a file in the user's home
        directory named .pydistutils.cfg on Unix and pydistutils.cfg
        on Windows/Mac; and setup.cfg in the current directory.

        The file in the user's home directory can be disabled with the
        --no-user-cfg option.
        """
        files = []
        check_environ()

        # Where to look for the system-wide Packaging config file
        sys_dir = os.path.dirname(sys.modules['packaging'].__file__)

        # Look for the system config file
        sys_file = os.path.join(sys_dir, "packaging.cfg")
        if os.path.isfile(sys_file):
            files.append(sys_file)

        # What to call the per-user config file
        if os.name == 'posix':
            user_filename = ".pydistutils.cfg"
        else:
            user_filename = "pydistutils.cfg"

        # And look for the user config file
        if self.dist.want_user_cfg:
            user_file = os.path.join(os.path.expanduser('~'), user_filename)
            if os.path.isfile(user_file):
                files.append(user_file)

        # All platforms support local setup.cfg
        local_file = "setup.cfg"
        if os.path.isfile(local_file):
            files.append(local_file)

        if logger.isEnabledFor(logging.DEBUG):
            logger.debug("using config files: %s", ', '.join(files))
        return files

    def _convert_metadata(self, name, value):
        # converts a value found in setup.cfg into a valid metadata
        # XXX
        return value

    def _read_setup_cfg(self, parser, cfg_filename):
        cfg_directory = os.path.dirname(os.path.abspath(cfg_filename))
        content = {}
        for section in parser.sections():
            content[section] = dict(parser.items(section))

        # global setup hooks are called first
        if 'global' in content:
            if 'setup_hooks' in content['global']:
                setup_hooks = split_multiline(content['global']['setup_hooks'])

                # add project directory to sys.path, to allow hooks to be
                # distributed with the project
                sys.path.insert(0, cfg_directory)
                try:
                    for line in setup_hooks:
                        try:
                            hook = resolve_name(line)
                        except ImportError as e:
                            logger.warning('cannot find setup hook: %s',
                                           e.args[0])
                        else:
                            self.setup_hooks.append(hook)
                    self.run_hooks(content)
                finally:
                    sys.path.pop(0)

        metadata = self.dist.metadata

        # setting the metadata values
        if 'metadata' in content:
            for key, value in content['metadata'].items():
                key = key.replace('_', '-')
                if metadata.is_multi_field(key):
                    value = split_multiline(value)

                if key == 'project-url':
                    value = [(label.strip(), url.strip())
                             for label, url in
                             [v.split(',') for v in value]]

                if key == 'description-file':
                    if 'description' in content['metadata']:
                        msg = ("description and description-file' are "
                               "mutually exclusive")
                        raise PackagingOptionError(msg)

                    filenames = value.split()

                    # concatenate all files
                    value = []
                    for filename in filenames:
                        # will raise if file not found
                        with open(filename) as description_file:
                            value.append(description_file.read().strip())
                        # add filename as a required file
                        if filename not in metadata.requires_files:
                            metadata.requires_files.append(filename)
                    value = '\n'.join(value).strip()
                    key = 'description'

                if metadata.is_metadata_field(key):
                    metadata[key] = self._convert_metadata(key, value)

        if 'files' in content:
            files = content['files']
            self.dist.package_dir = files.pop('packages_root', None)

            files = dict((key, split_multiline(value)) for key, value in
                         files.items())

            self.dist.packages = []

            packages = files.get('packages', [])
            if isinstance(packages, str):
                packages = [packages]

            for package in packages:
                if ':' in package:
                    dir_, package = package.split(':')
                    self.dist.package_dir[package] = dir_
                self.dist.packages.append(package)

            self.dist.py_modules = files.get('modules', [])
            if isinstance(self.dist.py_modules, str):
                self.dist.py_modules = [self.dist.py_modules]
            self.dist.scripts = files.get('scripts', [])
            if isinstance(self.dist.scripts, str):
                self.dist.scripts = [self.dist.scripts]

            self.dist.package_data = {}
            for line in files.get('package_data', []):
                data = line.split('=')
                if len(data) != 2:
                    raise ValueError('invalid line for package_data: %s '
                                     '(misses "=")' % line)
                key, value = data
                self.dist.package_data[key.strip()] = value.strip()

            self.dist.data_files = []
            for data in files.get('data_files', []):
                data = data.split('=')
                if len(data) != 2:
                    continue
                key, value = data
                values = [v.strip() for v in value.split(',')]
                self.dist.data_files.append((key, values))

            # manifest template
            self.dist.extra_files = files.get('extra_files', [])

            resources = []
            for rule in files.get('resources', []):
                glob, destination = rule.split('=', 1)
                rich_glob = glob.strip().split(' ', 1)
                if len(rich_glob) == 2:
                    prefix, suffix = rich_glob
                else:
                    assert len(rich_glob) == 1
                    prefix = ''
                    suffix = glob
                if destination == '<exclude>':
                    destination = None
                resources.append(
                    (prefix.strip(), suffix.strip(), destination.strip()))
                self.dist.data_files = get_resources_dests(
                    cfg_directory, resources)

        ext_modules = self.dist.ext_modules
        for section_key in content:
            # no str.partition in 2.4 :(
            labels = section_key.split(':')
            if len(labels) == 2 and labels[0] == 'extension':
                values_dct = content[section_key]
                if 'name' in values_dct:
                    raise PackagingOptionError(
                        'extension name should be given as [extension: name], '
                        'not as key')
                name = labels[1].strip()
                _check_name(name, self.dist.packages)
                ext_modules.append(Extension(
                    name,
                    _pop_values(values_dct, 'sources'),
                    _pop_values(values_dct, 'include_dirs'),
                    _pop_values(values_dct, 'define_macros'),
                    _pop_values(values_dct, 'undef_macros'),
                    _pop_values(values_dct, 'library_dirs'),
                    _pop_values(values_dct, 'libraries'),
                    _pop_values(values_dct, 'runtime_library_dirs'),
                    _pop_values(values_dct, 'extra_objects'),
                    _pop_values(values_dct, 'extra_compile_args'),
                    _pop_values(values_dct, 'extra_link_args'),
                    _pop_values(values_dct, 'export_symbols'),
                    _pop_values(values_dct, 'swig_opts'),
                    _pop_values(values_dct, 'depends'),
                    values_dct.pop('language', None),
                    values_dct.pop('optional', None),
                    **values_dct))

    def parse_config_files(self, filenames=None):
        if filenames is None:
            filenames = self.find_config_files()

        logger.debug("Distribution.parse_config_files():")

        parser = RawConfigParser()

        for filename in filenames:
            logger.debug("  reading %s", filename)
            parser.read(filename, encoding='utf-8')

            if os.path.split(filename)[-1] == 'setup.cfg':
                self._read_setup_cfg(parser, filename)

            for section in parser.sections():
                if section == 'global':
                    if parser.has_option('global', 'compilers'):
                        self._load_compilers(parser.get('global', 'compilers'))

                    if parser.has_option('global', 'commands'):
                        self._load_commands(parser.get('global', 'commands'))

                options = parser.options(section)
                opt_dict = self.dist.get_option_dict(section)

                for opt in options:
                    if opt == '__name__':
                        continue
                    val = parser.get(section, opt)
                    opt = opt.replace('-', '_')

                    if opt == 'sub_commands':
                        val = split_multiline(val)
                        if isinstance(val, str):
                            val = [val]

                    # Hooks use a suffix system to prevent being overriden
                    # by a config file processed later (i.e. a hook set in
                    # the user config file cannot be replaced by a hook
                    # set in a project config file, unless they have the
                    # same suffix).
                    if (opt.startswith("pre_hook.") or
                        opt.startswith("post_hook.")):
                        hook_type, alias = opt.split(".")
                        hook_dict = opt_dict.setdefault(
                            hook_type, (filename, {}))[1]
                        hook_dict[alias] = val
                    else:
                        opt_dict[opt] = filename, val

            # Make the RawConfigParser forget everything (so we retain
            # the original filenames that options come from)
            parser.__init__()

        # If there was a "global" section in the config file, use it
        # to set Distribution options.
        if 'global' in self.dist.command_options:
            for opt, (src, val) in self.dist.command_options['global'].items():
                alias = self.dist.negative_opt.get(opt)
                try:
                    if alias:
                        setattr(self.dist, alias, not strtobool(val))
                    elif opt == 'dry_run':  # FIXME ugh!
                        setattr(self.dist, opt, strtobool(val))
                    else:
                        setattr(self.dist, opt, val)
                except ValueError as msg:
                    raise PackagingOptionError(msg)

    def _load_compilers(self, compilers):
        compilers = split_multiline(compilers)
        if isinstance(compilers, str):
            compilers = [compilers]
        for compiler in compilers:
            set_compiler(compiler.strip())

    def _load_commands(self, commands):
        commands = split_multiline(commands)
        if isinstance(commands, str):
            commands = [commands]
        for command in commands:
            set_command(command.strip())
