# coding=utf8
from __future__ import unicode_literals

import imp
import os.path
import re
import sys

from willie.tools import itervalues, get_command_regexp


def get_module_description(path):
    good_file = (os.path.isfile(path) and path.endswith('.py')
                 and not path.startswith('_'))
    good_dir = (os.path.isdir(path) and
                os.path.isfile(os.path.join(path, '__init__.py')))
    if good_file:
        name = os.path.basename(path)[:-3]
        return (name, path, imp.PY_SOURCE)
    elif good_dir:
        name = os.path.basename(path)
        return (name, path, imp.PKG_DIRECTORY)
    else:
        return None


def enumerate_modules(config, show_all=False):
    """Map the names of modules to the location of their file.

    Return a dict mapping the names of modules to a tuple of the module name,
    the pathname and either `imp.PY_SOURCE` or `imp.PKG_DIRECTORY`. This
    searches the regular modules directory and all directories specified in the
    `core.extra` attribute of the `config` object. If two modules have the same
    name, the last one to be found will be returned and the rest will be
    ignored. Modules are found starting in the regular directory, followed by
    `~/.willie/modules`, and then through the extra directories in the order
    that the are specified.

    If `show_all` is given as `True`, the `enable` and `exclude`
    configuration options will be ignored, and all modules will be shown
    (though duplicates will still be ignored as above).
    """
    modules = {}

    # First, add modules from the regular modules directory
    main_dir = os.path.dirname(os.path.abspath(__file__))
    modules_dir = os.path.join(main_dir, 'modules')
    for path in os.listdir(modules_dir):
        result = get_module_description(os.path.join(modules_dir, path))
        if result:
            modules[result[0]] = result[1:]
    # Next, look in ~/.willie/modules
    if config.core.homedir is not None:
        home_modules_dir = os.path.join(config.core.homedir, 'modules')
    else:
        home_modules_dir = os.path.join(os.path.expanduser('~'), '.willie',
                                        'modules')
    if not os.path.isdir(home_modules_dir):
        os.makedirs(home_modules_dir)
    for path in os.listdir(home_modules_dir):
        path = os.path.join(home_modules_dir, path)
        result = get_module_description(path)
        if result:
            modules[result[0]] = result[1:]

    # Last, look at all the extra directories.
    for directory in config.core.extra:
        for path in os.listdir(directory):
            path = os.path.join(directory, path)
            result = get_module_description(path)
            if result:
                modules[result[0]] = result[1:]

    # Coretasks is special. No custom user coretasks.
    ct_path = os.path.join(main_dir, 'coretasks.py')
    modules['coretasks'] = (ct_path, imp.PY_SOURCE)

    # If caller wants all of them, don't apply white and blacklists
    if show_all:
        return modules

    # Apply whitelist, if present
    enable = config.core.enable
    if enable:
        enabled_modules = {'coretasks': modules['coretasks']}
        for module in enable:
            if module in modules:
                enabled_modules[module] = modules[module]
        modules = enabled_modules

    # Apply blacklist, if present
    exclude = config.core.exclude
    for module in exclude:
        if module in modules:
            del modules[module]

    return modules


def compile_rule(nick, pattern):
    pattern = pattern.replace('$nickname', nick)
    pattern = pattern.replace('$nick', r'{}[,:]\s+'.format(nick))
    flags = re.IGNORECASE
    if '\n' in pattern:
        flags |= re.VERBOSE
    return re.compile(pattern, flags)


def trim_docstring(doc):
    """Get the docstring as a series of lines that can be sent"""
    if not doc:
        return []
    lines = doc.expandtabs().splitlines()
    indent = sys.maxsize
    for line in lines[1:]:
        stripped = line.lstrip()
        if stripped:
            indent = min(indent, len(line) - len(stripped))
    trimmed = [lines[0].strip()]
    if indent < sys.maxsize:
        for line in lines[1:]:
            trimmed.append(line[:].rstrip())
    while trimmed and not trimmed[-1]:
        trimmed.pop()
    while trimmed and not trimmed[0]:
        trimmed.pop(0)
    return trimmed


def clean_callable(func, config):
    """Compiles the regexes, moves commands into func.rule, fixes up docs and
    puts them in func._docs, and sets defaults"""
    nick = config.core.nick
    prefix = config.core.prefix
    help_prefix = config.core.prefix
    func._docs = {}
    doc = trim_docstring(func.__doc__)
    example = None

    func.unblockable = getattr(func, 'unblockable', True)
    func.priority = getattr(func, 'priority', 'medium')
    func.thread = getattr(func, 'thread', True)
    func.rate = getattr(func, 'rate', 0)

    if not hasattr(func, 'event'):
        func.event = ['PRIVMSG']
    else:
        if isinstance(func.event, basestring):
            func.event = [func.event.upper()]
        else:
            func.event = [event.upper() for event in func.event]

    if hasattr(func, 'rule'):
        if isinstance(func.rule, basestring):
            func.rule = [func.rule]
        func.rule = [compile_rule(nick, rule) for rule in func.rule]

    if hasattr(func, 'commands'):
        func.rule = getattr(func, 'rule', [])
        for command in func.commands:
            regexp = get_command_regexp(prefix, command)
            func.rule.append(regexp)
        if hasattr(func, 'example'):
            example = func.example[0]["example"]
            example = example.replace('$nickname', nick)
            if example[0] != help_prefix:
                example = help_prefix + example[len(help_prefix):]
        if doc or example:
            for command in func.commands:
                func._docs[command] = (doc, example)


def load_module(name, path, type_):
    """Load a module, and sort out the callables and shutdowns"""
    if type_ == imp.PY_SOURCE:
        module = imp.load_module(name, open(path), path, ('.py', 'U', type_))
    elif type_ == imp.PKG_DIRECTORY:
        module = imp.load_module(name, None, path, ('', '', type_))
    else:
        raise TypeError('Unsupported module type')
    return module, os.path.getmtime(path)


def clean_module(module, config):
    callables = []
    shutdowns = []
    jobs = []
    for obj in itervalues(vars(module)):
        if callable(obj):
            if getattr(obj, '__name__', None) == 'shutdown':
                shutdowns.append(obj)
            elif (hasattr(obj, 'commands') or hasattr(obj, 'rule') or
                  hasattr(obj, 'intent')):
                clean_callable(obj, config)
                callables.append(obj)
            elif hasattr(obj, 'interval'):
                clean_callable(obj, config)
                jobs.append(obj)
    return callables, jobs, shutdowns