from __future__ import print_function

import codecs
from collections import OrderedDict
import fnmatch
import logging
import os
import uuid

import yaml
import yaml.constructor

from esphomeyaml import core
from esphomeyaml.core import EsphomeyamlError, HexInt, IPAddress, Lambda, MACAddress, TimePeriod

_LOGGER = logging.getLogger(__name__)

# Mostly copied from Home Assistant because that code works fine and
# let's not reinvent the wheel here

SECRET_YAML = u'secrets.yaml'


class NodeListClass(list):
    """Wrapper class to be able to add attributes on a list."""

    pass


class NodeStrClass(unicode):
    """Wrapper class to be able to add attributes on a string."""

    pass


class SafeLineLoader(yaml.SafeLoader):  # pylint: disable=too-many-ancestors
    """Loader class that keeps track of line numbers."""

    def compose_node(self, parent, index):
        """Annotate a node with the first line it was seen."""
        last_line = self.line  # type: int
        node = super(SafeLineLoader, self).compose_node(parent, index)  # type: yaml.nodes.Node
        node.__line__ = last_line + 1
        return node


def load_yaml(fname):
    """Load a YAML file."""
    try:
        with codecs.open(fname, encoding='utf-8') as conf_file:
            return yaml.load(conf_file, Loader=SafeLineLoader) or OrderedDict()
    except yaml.YAMLError as exc:
        raise EsphomeyamlError(exc)
    except IOError as exc:
        raise EsphomeyamlError(u"Error accessing file {}: {}".format(fname, exc))
    except UnicodeDecodeError as exc:
        _LOGGER.error(u"Unable to read file %s: %s", fname, exc)
        raise EsphomeyamlError(exc)


def dump(dict_):
    """Dump YAML to a string and remove null."""
    return yaml.safe_dump(
        dict_, default_flow_style=False, allow_unicode=True)


def custom_construct_pairs(loader, node):
    pairs = []
    for kv in node.value:
        if isinstance(kv, yaml.ScalarNode):
            obj = loader.construct_object(kv)
            if not isinstance(obj, dict):
                raise EsphomeyamlError(
                    "Expected mapping for anchored include tag, got {}".format(type(obj)))
            for key, value in obj.iteritems():
                pairs.append((key, value))
        else:
            key_node, value_node = kv
            key = loader.construct_object(key_node)
            value = loader.construct_object(value_node)
            pairs.append((key, value))

    return pairs


def custom_flatten_mapping(loader, node):
    pre_merge = []
    post_merge = []
    index = 0
    while index < len(node.value):
        if isinstance(node.value[index], yaml.ScalarNode):
            index += 1
            continue

        key_node, value_node = node.value[index]
        if key_node.tag == u'tag:yaml.org,2002:merge':
            del node.value[index]

            if isinstance(value_node, yaml.MappingNode):
                custom_flatten_mapping(loader, value_node)
                node.value = node.value[:index] + value_node.value + node.value[index:]
            elif isinstance(value_node, yaml.SequenceNode):
                submerge = []
                for subnode in value_node.value:
                    if not isinstance(subnode, yaml.MappingNode):
                        raise yaml.constructor.ConstructorError(
                            "while constructing a mapping", node.start_mark,
                            "expected a mapping for merging, but found %{}".format(subnode.id),
                            subnode.start_mark)
                    custom_flatten_mapping(loader, subnode)
                    submerge.append(subnode.value)
                # submerge.reverse()
                node.value = node.value[:index] + submerge + node.value[index:]
            elif isinstance(value_node, yaml.ScalarNode):
                node.value = node.value[:index] + [value_node] + node.value[index:]
                # post_merge.append(value_node)
            else:
                raise yaml.constructor.ConstructorError(
                    "while constructing a mapping", node.start_mark,
                    "expected a mapping or list of mappings for merging, "
                    "but found {}".format(value_node.id), value_node.start_mark)
        elif key_node.tag == u'tag:yaml.org,2002:value':
            key_node.tag = u'tag:yaml.org,2002:str'
            index += 1
        else:
            index += 1
    if pre_merge:
        node.value = pre_merge + node.value
    if post_merge:
        node.value = node.value + post_merge


def _ordered_dict(loader, node):
    """Load YAML mappings into an ordered dictionary to preserve key order."""
    custom_flatten_mapping(loader, node)
    nodes = custom_construct_pairs(loader, node)

    seen = {}
    for (key, _), nv in zip(nodes, node.value):
        if isinstance(nv, yaml.ScalarNode):
            line = nv.start_mark.line
        else:
            line = nv[0].start_mark.line

        try:
            hash(key)
        except TypeError:
            fname = getattr(loader.stream, 'name', '')
            raise yaml.MarkedYAMLError(
                context="invalid key: \"{}\"".format(key),
                context_mark=yaml.Mark(fname, 0, line, -1, None, None)
            )

        if key in seen:
            fname = getattr(loader.stream, 'name', '')
            raise EsphomeyamlError(u'YAML file {} contains duplicate key "{}". '
                                   u'Check lines {} and {}.'.format(fname, key, seen[key], line))
        seen[key] = line

    return _add_reference(OrderedDict(nodes), loader, node)


def _construct_seq(loader, node):
    """Add line number and file name to Load YAML sequence."""
    obj, = loader.construct_yaml_seq(node)
    return _add_reference(obj, loader, node)


def _add_reference(obj, loader, node):
    """Add file reference information to an object."""
    if isinstance(obj, (str, unicode)):
        obj = NodeStrClass(obj)
    if isinstance(obj, list):
        return obj
    setattr(obj, '__config_file__', loader.name)
    setattr(obj, '__line__', node.start_mark.line)
    return obj


def _env_var_yaml(_, node):
    """Load environment variables and embed it into the configuration YAML."""
    args = node.value.split()

    # Check for a default value
    if len(args) > 1:
        return os.getenv(args[0], u' '.join(args[1:]))
    elif args[0] in os.environ:
        return os.environ[args[0]]
    raise EsphomeyamlError(u"Environment variable {} not defined.".format(node.value))


def _include_yaml(loader, node):
    """Load another YAML file and embeds it using the !include tag.

    Example:
        device_tracker: !include device_tracker.yaml
    """
    fname = os.path.join(os.path.dirname(loader.name), node.value)
    return _add_reference(load_yaml(fname), loader, node)


def _is_file_valid(name):
    """Decide if a file is valid."""
    return not name.startswith(u'.')


def _find_files(directory, pattern):
    """Recursively load files in a directory."""
    for root, dirs, files in os.walk(directory, topdown=True):
        dirs[:] = [d for d in dirs if _is_file_valid(d)]
        for basename in files:
            if _is_file_valid(basename) and fnmatch.fnmatch(basename, pattern):
                filename = os.path.join(root, basename)
                yield filename


def _include_dir_named_yaml(loader, node):
    """Load multiple files from directory as a dictionary."""
    mapping = OrderedDict()  # type: OrderedDict
    loc = os.path.join(os.path.dirname(loader.name), node.value)
    for fname in _find_files(loc, '*.yaml'):
        filename = os.path.splitext(os.path.basename(fname))[0]
        mapping[filename] = load_yaml(fname)
    return _add_reference(mapping, loader, node)


def _include_dir_merge_named_yaml(loader, node):
    """Load multiple files from directory as a merged dictionary."""
    mapping = OrderedDict()  # type: OrderedDict
    loc = os.path.join(os.path.dirname(loader.name), node.value)
    for fname in _find_files(loc, '*.yaml'):
        if os.path.basename(fname) == SECRET_YAML:
            continue
        loaded_yaml = load_yaml(fname)
        if isinstance(loaded_yaml, dict):
            mapping.update(loaded_yaml)
    return _add_reference(mapping, loader, node)


def _include_dir_list_yaml(loader, node):
    """Load multiple files from directory as a list."""
    loc = os.path.join(os.path.dirname(loader.name), node.value)
    return [load_yaml(f) for f in _find_files(loc, '*.yaml')
            if os.path.basename(f) != SECRET_YAML]


def _include_dir_merge_list_yaml(loader, node):
    """Load multiple files from directory as a merged list."""
    path = os.path.join(os.path.dirname(loader.name), node.value)
    merged_list = []
    for fname in _find_files(path, '*.yaml'):
        if os.path.basename(fname) == SECRET_YAML:
            continue
        loaded_yaml = load_yaml(fname)
        if isinstance(loaded_yaml, list):
            merged_list.extend(loaded_yaml)
    return _add_reference(merged_list, loader, node)


# pylint: disable=protected-access
def _secret_yaml(loader, node):
    """Load secrets and embed it into the configuration YAML."""
    secret_path = os.path.join(os.path.dirname(loader.name), SECRET_YAML)
    secrets = load_yaml(secret_path)
    if node.value not in secrets:
        raise EsphomeyamlError(u"Secret {} not defined".format(node.value))
    return secrets[node.value]


def _lambda(loader, node):
    return Lambda(unicode(node.value))


yaml.SafeLoader.add_constructor(yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG, _ordered_dict)
yaml.SafeLoader.add_constructor(yaml.resolver.BaseResolver.DEFAULT_SEQUENCE_TAG, _construct_seq)
yaml.SafeLoader.add_constructor('!env_var', _env_var_yaml)
yaml.SafeLoader.add_constructor('!secret', _secret_yaml)
yaml.SafeLoader.add_constructor('!include', _include_yaml)
yaml.SafeLoader.add_constructor('!include_dir_list', _include_dir_list_yaml)
yaml.SafeLoader.add_constructor('!include_dir_merge_list',
                                _include_dir_merge_list_yaml)
yaml.SafeLoader.add_constructor('!include_dir_named', _include_dir_named_yaml)
yaml.SafeLoader.add_constructor('!include_dir_merge_named',
                                _include_dir_merge_named_yaml)
yaml.SafeLoader.add_constructor('!lambda', _lambda)


# From: https://gist.github.com/miracle2k/3184458
# pylint: disable=redefined-outer-name
def represent_odict(dump, tag, mapping, flow_style=None):
    """Like BaseRepresenter.represent_mapping but does not issue the sort()."""
    value = []
    node = yaml.MappingNode(tag, value, flow_style=flow_style)
    if dump.alias_key is not None:
        dump.represented_objects[dump.alias_key] = node
    best_style = True
    if hasattr(mapping, 'items'):
        mapping = mapping.items()
    for item_key, item_value in mapping:
        node_key = dump.represent_data(item_key)
        node_value = dump.represent_data(item_value)
        if not (isinstance(node_key, yaml.ScalarNode) and not node_key.style):
            best_style = False
        if not (isinstance(node_value, yaml.ScalarNode) and
                not node_value.style):
            best_style = False
        value.append((node_key, node_value))
    if flow_style is None:
        if dump.default_flow_style is not None:
            node.flow_style = dump.default_flow_style
        else:
            node.flow_style = best_style
    return node


def unicode_representer(_, uni):
    node = yaml.ScalarNode(tag=u'tag:yaml.org,2002:str', value=uni)
    return node


def hex_int_representer(_, data):
    node = yaml.ScalarNode(tag=u'tag:yaml.org,2002:int', value=str(data))
    return node


def stringify_representer(_, data):
    node = yaml.ScalarNode(tag=u'tag:yaml.org,2002:str', value=str(data))
    return node


TIME_PERIOD_UNIT_MAP = {
    'microseconds': 'us',
    'milliseconds': 'ms',
    'seconds': 's',
    'minutes': 'min',
    'hours': 'h',
    'days': 'd',
}


def represent_time_period(dumper, data):
    dictionary = data.as_dict()
    if len(dictionary) == 1:
        unit, value = dictionary.popitem()
        out = '{}{}'.format(value, TIME_PERIOD_UNIT_MAP[unit])
        return yaml.ScalarNode(tag=u'tag:yaml.org,2002:str', value=out)
    return represent_odict(dumper, 'tag:yaml.org,2002:map', dictionary)


def represent_lambda(_, data):
    node = yaml.ScalarNode(tag='!lambda', value=data.value, style='|')
    return node


def represent_id(_, data):
    return yaml.ScalarNode(tag=u'tag:yaml.org,2002:str', value=data.id)


def represent_uuid(_, data):
    return yaml.ScalarNode(tag=u'tag:yaml.org,2002:str', value=str(data))


yaml.SafeDumper.add_representer(
    OrderedDict,
    lambda dumper, value:
    represent_odict(dumper, 'tag:yaml.org,2002:map', value)
)

yaml.SafeDumper.add_representer(
    NodeListClass,
    lambda dumper, value:
    dumper.represent_sequence(dumper, 'tag:yaml.org,2002:map', value)
)

yaml.SafeDumper.add_representer(unicode, unicode_representer)
yaml.SafeDumper.add_representer(HexInt, hex_int_representer)
yaml.SafeDumper.add_representer(IPAddress, stringify_representer)
yaml.SafeDumper.add_representer(MACAddress, stringify_representer)
yaml.SafeDumper.add_multi_representer(TimePeriod, represent_time_period)
yaml.SafeDumper.add_multi_representer(Lambda, represent_lambda)
yaml.SafeDumper.add_multi_representer(core.ID, represent_id)
yaml.SafeDumper.add_multi_representer(uuid.UUID, represent_uuid)