# Copyright 2008-2016 Free Software Foundation, Inc.
# This file is part of GNU Radio
#
# GNU Radio Companion is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# GNU Radio Companion is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA

from __future__ import absolute_import, print_function

from codecs import open
from collections import namedtuple
import glob
import os
import logging
from itertools import chain

import six
from six.moves import range

from . import (
    Messages, Constants,
    blocks, ports, errors, utils, schema_checker
)

from .Config import Config
from .base import Element
from .io import yaml
from .generator import Generator
from .FlowGraph import FlowGraph
from .Connection import Connection
from .Param import Param

logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO)


class Platform(Element):

    def __init__(self, *args, **kwargs):
        """ Make a platform for GNU Radio """
        Element.__init__(self, parent=None)

        self.config = self.Config(*args, **kwargs)
        self.block_docstrings = {}
        self.block_docstrings_loaded_callback = lambda: None  # dummy to be replaced by BlockTreeWindow

        self._docstring_extractor = utils.extract_docs.SubprocessLoader(
            callback_query_result=self._save_docstring_extraction_result,
            callback_finished=lambda: self.block_docstrings_loaded_callback()
        )

        self.blocks = self.block_classes
        self.domains = {}
        self.connection_templates = {}

        self._block_categories = {}
        self._auto_hier_block_generate_chain = set()

        if not yaml.__with_libyaml__:
            logger.warning("Slow YAML loading (libyaml not available)")

    def __str__(self):
        return 'Platform - {}'.format(self.config.name)

    @staticmethod
    def find_file_in_paths(filename, paths, cwd):
        """Checks the provided paths relative to cwd for a certain filename"""
        if not os.path.isdir(cwd):
            cwd = os.path.dirname(cwd)
        if isinstance(paths, str):
            paths = (p for p in paths.split(':') if p)

        for path in paths:
            path = os.path.expanduser(path)
            if not os.path.isabs(path):
                path = os.path.normpath(os.path.join(cwd, path))
            file_path = os.path.join(path, filename)
            if os.path.exists(os.path.normpath(file_path)):
                return file_path

    def load_and_generate_flow_graph(self, file_path, out_path=None, hier_only=False):
        """Loads a flow graph from file and generates it"""
        Messages.set_indent(len(self._auto_hier_block_generate_chain))
        Messages.send('>>> Loading: {}\n'.format(file_path))
        if file_path in self._auto_hier_block_generate_chain:
            Messages.send('    >>> Warning: cyclic hier_block dependency\n')
            return None, None
        self._auto_hier_block_generate_chain.add(file_path)
        try:
            flow_graph = self.make_flow_graph()
            flow_graph.grc_file_path = file_path
            # Other, nested hier_blocks might be auto-loaded here
            flow_graph.import_data(self.parse_flow_graph(file_path))
            flow_graph.rewrite()
            flow_graph.validate()
            if not flow_graph.is_valid():
                raise Exception('Flowgraph invalid')
            if hier_only and not flow_graph.get_option('generate_options').startswith('hb'):
                raise Exception('Not a hier block')
        except Exception as e:
            Messages.send('>>> Load Error: {}: {}\n'.format(file_path, str(e)))
            return None, None
        finally:
            self._auto_hier_block_generate_chain.discard(file_path)
            Messages.set_indent(len(self._auto_hier_block_generate_chain))

        try:
            generator = self.Generator(flow_graph, out_path or file_path)
            Messages.send('>>> Generating: {}\n'.format(generator.file_path))
            generator.write()
        except Exception as e:
            Messages.send('>>> Generate Error: {}: {}\n'.format(file_path, str(e)))
            return None, None

        if flow_graph.get_option('generate_options').startswith('hb'):
            # self.load_block_xml(generator.file_path_xml)
            # TODO: implement yml output for hier blocks
            pass
        return flow_graph, generator.file_path

    def build_library(self, path=None):
        """load the blocks and block tree from the search paths

        path: a list of paths/files to search in or load (defaults to config)
        """
        self._docstring_extractor.start()

        # Reset
        self.blocks.clear()
        self.domains.clear()
        self.connection_templates.clear()
        self._block_categories.clear()

        # FIXME: remove this as soon as converter is stable
        from ..converter import Converter
        converter = Converter(self.config.block_paths, self.config.yml_block_cache)
        converter.run()
        logging.info('XML converter done.')

        for file_path in self._iter_files_in_block_path(path):
            try:
                data = converter.cache[file_path]
            except KeyError:
                with open(file_path, encoding='utf-8') as fp:
                    data = yaml.safe_load(fp)

            if file_path.endswith('.block.yml'):
                loader = self.load_block_description
                scheme = schema_checker.BLOCK_SCHEME
            elif file_path.endswith('.domain.yml'):
                loader = self.load_domain_description
                scheme = schema_checker.DOMAIN_SCHEME
            elif file_path.endswith('.tree.yml'):
                loader = self.load_category_tree_description
                scheme = None
            else:
                continue

            try:
                checker = schema_checker.Validator(scheme)
                passed = checker.run(data)
                for msg in checker.messages:
                    logger.warning('{:<40s} {}'.format(os.path.basename(file_path), msg))
                if not passed:
                    logger.info('YAML schema check failed for: ' + file_path)

                loader(data, file_path)
            except Exception as error:
                logger.exception('Error while loading %s', file_path)
                logger.exception(error)
                raise

        for key, block in six.iteritems(self.blocks):
            category = self._block_categories.get(key, block.category)
            if not category:
                continue
            root = category[0]
            if root.startswith('[') and root.endswith(']'):
                category[0] = root[1:-1]
            else:
                category.insert(0, Constants.DEFAULT_BLOCK_MODULE_NAME)
            block.category = category

        self._docstring_extractor.finish()
        # self._docstring_extractor.wait()

    def _iter_files_in_block_path(self, path=None, ext='yml'):
        """Iterator for block descriptions and category trees"""
        for entry in (path or self.config.block_paths):
            if os.path.isfile(entry):
                yield entry
            elif os.path.isdir(entry):
                pattern = os.path.join(entry, '**.' + ext)
                yield_from = glob.iglob(pattern)
                for file_path in yield_from:
                    yield file_path
            else:
                logger.debug('Ignoring invalid path entry %r', entry)

    def _save_docstring_extraction_result(self, block_id, docstrings):
        docs = {}
        for match, docstring in six.iteritems(docstrings):
            if not docstring or match.endswith('_sptr'):
                continue
            docs[match] = docstring.replace('\n\n', '\n').strip()
        try:
            self.blocks[block_id].documentation.update(docs)
        except KeyError:
            pass  # in tests platform might be gone...

    ##############################################
    # Description File Loaders
    ##############################################
    # region loaders
    def load_block_description(self, data, file_path):
        log = logger.getChild('block_loader')

        # don't load future block format versions
        file_format = data['file_format']
        if file_format < 1 or file_format > Constants.BLOCK_DESCRIPTION_FILE_FORMAT_VERSION:
            log.error('Unknown format version %d in %s', file_format, file_path)
            return

        block_id = data.pop('id').rstrip('_')

        if block_id in self.block_classes_build_in:
            log.warning('Not overwriting build-in block %s with %s', block_id, file_path)
            return
        if block_id in self.blocks:
            log.warning('Block with id "%s" overwritten by %s', block_id, file_path)

        try:
            block_cls = self.blocks[block_id] = self.new_block_class(block_id, **data)
        except errors.BlockLoadError as error:
            log.error('Unable to load block %s', block_id)
            log.exception(error)
            return

        self._docstring_extractor.query(
            block_id, block_cls.templates['imports'], block_cls.templates['make'],
        )

    def load_domain_description(self, data, file_path):
        log = logger.getChild('domain_loader')
        domain_id = data['id']
        if domain_id in self.domains:  # test against repeated keys
            log.debug('Domain "{}" already exists. Ignoring: %s', file_path)
            return

        color = data.get('color', '')
        if color.startswith('#'):
            try:
                tuple(int(color[o:o + 2], 16) / 255.0 for o in range(1, 6, 2))
            except ValueError:
                log.warning('Cannot parse color code "%s" in %s', color, file_path)
                return

        self.domains[domain_id] = self.Domain(
            name=data.get('label', domain_id),
            multi_in=data.get('multiple_connections_per_input', True),
            multi_out=data.get('multiple_connections_per_output', False),
            color=color
        )
        for connection in data.get('templates', []):
            try:
                source_id, sink_id = connection.get('type', [])
            except ValueError:
                log.warn('Invalid connection template.')
                continue
            connection_id = str(source_id), str(sink_id)
            self.connection_templates[connection_id] = connection.get('connect', '')

    def load_category_tree_description(self, data, file_path):
        """Parse category tree file and add it to list"""
        log = logger.getChild('tree_loader')
        log.debug('Loading %s', file_path)
        path = []

        def load_category(name, elements):
            if not isinstance(name, str):
                log.debug('invalid name %r', name)
                return
            if isinstance(elements, list):
                pass
            elif isinstance(elements, str):
                elements = [elements]
            else:
                log.debug('Ignoring elements of %s', name)
                return
            path.append(name)
            for element in elements:
                if isinstance(element, str):
                    block_id = element
                    self._block_categories[block_id] = list(path)
                elif isinstance(element, dict):
                    load_category(*next(six.iteritems(element)))
                else:
                    log.debug('Ignoring some elements of %s', name)
            path.pop()

        try:
            module_name, categories = next(six.iteritems(data))
        except (AttributeError, StopIteration):
            log.warning('no valid data found')
        else:
            load_category(module_name, categories)

    ##############################################
    # Access
    ##############################################
    def parse_flow_graph(self, filename):
        """
        Parse a saved flow graph file.
        Ensure that the file exists, and passes the dtd check.

        Args:
            filename: the flow graph file

        Returns:
            nested data
        @throws exception if the validation fails
        """
        filename = filename or self.config.default_flow_graph
        with open(filename, encoding='utf-8') as fp:
            is_xml = '<flow_graph>' in fp.read(100)
            fp.seek(0)
            # todo: try
            if not is_xml:
                data = yaml.safe_load(fp)
                validator = schema_checker.Validator(schema_checker.FLOW_GRAPH_SCHEME)
                validator.run(data)
            else:
                Messages.send('>>> Converting from XML\n')
                from ..converter.flow_graph import from_xml
                data = from_xml(fp)

        return data

    def save_flow_graph(self, filename, flow_graph):
        data = flow_graph.export_data()

        try:
            data['connections'] = [yaml.ListFlowing(i) for i in data['connections']]
        except KeyError:
            pass

        try:
            for d in chain([data['options']], data['blocks']):
                d['states']['coordinate'] = yaml.ListFlowing(d['states']['coordinate'])
                for param_id, value in list(d['parameters'].items()):
                    if value == '':
                        d['parameters'].pop(param_id)
        except KeyError:
            pass

        out = yaml.dump(data, indent=2)

        replace = [
            ('blocks:', '\nblocks:'),
            ('connections:', '\nconnections:'),
            ('metadata:', '\nmetadata:'),
        ]
        for r in replace:
            out = out.replace(*r)

        with open(filename, 'w', encoding='utf-8') as fp:
            fp.write(out)

    def get_generate_options(self):
        for param in self.block_classes['options'].parameters_data:
            if param.get('id') == 'generate_options':
                break
        else:
            return []
        generate_mode_default = param.get('default')
        return [(value, name, value == generate_mode_default)
                for value, name in zip(param['options'], param['option_labels'])]

    ##############################################
    # Factories
    ##############################################
    Config = Config
    Domain = namedtuple('Domain', 'name multi_in multi_out color')
    Generator = Generator
    FlowGraph = FlowGraph
    Connection = Connection

    block_classes_build_in = blocks.build_ins
    block_classes = utils.backports.ChainMap({}, block_classes_build_in)  # separates build-in from loaded blocks)

    port_classes = {
        None: ports.Port,  # default
        'clone': ports.PortClone,  # clone of ports with multiplicity > 1
    }
    param_classes = {
        None: Param,  # default
    }

    def make_flow_graph(self, from_filename=None):
        fg = self.FlowGraph(parent=self)
        if from_filename:
            data = self.parse_flow_graph(from_filename)
            fg.grc_file_path = from_filename
            fg.import_data(data)
        return fg

    def new_block_class(self, block_id, **data):
        return blocks.build(block_id, **data)

    def make_block(self, parent, block_id, **kwargs):
        cls = self.block_classes[block_id]
        return cls(parent, **kwargs)

    def make_param(self, parent, **kwargs):
        cls = self.param_classes[kwargs.pop('cls_key', None)]
        return cls(parent, **kwargs)

    def make_port(self, parent, **kwargs):
        cls = self.port_classes[kwargs.pop('cls_key', None)]
        return cls(parent, **kwargs)