# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import glob
import re
import os
from . import config
from . import util
from collections import defaultdict
from fuzzywuzzy import fuzz
from operator import attrgetter

RE_WIKILINKS = re.compile('\[\[(.*?)\]\]')
FUZZ_FACTOR = 95

# URIs are ids. 
# - In the case of nodes, their [[wikilink]].
#   - Example: 'foo', meaning the node that is rendered when you click on [[foo]] somewhere.
# - In the case of subnodes, a relative path within the Agora.
#   - Example: 'garden/flancian/README.md', meaning an actual file called README.md.
#   - Note the example subnode above gets rendered in node [[README]], so fetching node with uri README would yield it (and others).

# TODO: implement.
class Graph:
    def __init__(self):
        # [[wikilink]] -> Node
        self.nodes = {}
        # node -> [n0, ..., nn] such that node has outlinks to the target list.
        self.edges = {}
    def addsubnode(self, subnode):
        if subnode.wikilink in self.nodes:
            G.nodes[subnode.wikilink].subnodes.append(subnode)
        else:
            G.nodes[subnode.wikilink] = Node(subnode.wikilink)

G = Graph()

class Node:
    """Nodes map 1:1 to wikilinks.
    They resolve to a series of subnodes when being rendered (see below).
    It maps to a particular file in the Agora repository, stored (relative to 
    the Agora root) in the attribute 'uri'."""
    def __init__(self, wikilink):
        # Use a node's URI as its identifier.
        # Subnodes are attached to the node matching their wikilink.
        # i.e. if two users contribute subnodes titled [[foo]], they both show up when querying node [[foo]].
        self.wikilink = wikilink
        self.uri = wikilink
        self.url = '/node/' + self.uri
        self.subnodes = []

    def size(self):
        return len(self.subnodes)

class Subnode:
    """A subnode is a note or media resource volunteered by a user of the Agora.
    It maps to a particular file in the Agora repository, stored (relative to 
    the Agora root) in the attribute 'uri'."""
    def __init__(self, path):
        # Use a subnode's URI as its identifier.
        self.uri = path_to_uri(path)
        self.url = '/subnode/' + path_to_uri(path)
        # Subnodes are attached to the node matching their wikilink.
        # i.e. if two users contribute subnodes titled [[foo]], they both show up when querying node [[foo]].
        self.wikilink = util.canonical_wikilink(path_to_wikilink(path))
        self.user = path_to_user(path)
        with open(path) as f:
            self.content = f.read()
        self.outlinks = content_to_outlinks(self.content)
        self.node = self.wikilink
        # Initiate node for wikilink if this is the first subnode, append otherwise.
        G.addsubnode(self)

    def __eq__(self, other):
        # hack hack
        if fuzz.ratio(self.wikilink, other.wikilink) > FUZZ_FACTOR:
            return True
        else:
            return False

    def __sub__(self, other):
        # hack hack
        return 100-fuzz.ratio(self.wikilink, other.wikilink)

    def distance(self, other):
        # hack hack
        return 100-fuzz.ratio(self.wikilink, other.wikilink)


class User:
    def __init__(self, user):
        self.uri = user
        self.url = '/user/' + self.uri

def path_to_uri(path):
    return path.replace(config.AGORA_PATH + '/', '')

def path_to_user(path):
    m = re.search('garden/(.+?)/', path)
    if m:
        return m.group(1)
    else:
        return 'agora'

def path_to_wikilink(path):
    return os.path.splitext(os.path.basename(path))[0]

def content_to_outlinks(content):
    # hack hack.
    match = RE_WIKILINKS.findall(content)
    if match:
        return [util.canonical_wikilink(m) for m in match]
    else:
        return []

def all_subnodes():
    subnodes = [Subnode(f) for f in glob.glob(os.path.join(config.AGORA_PATH, '**/*.md'), recursive=True)]
    return sorted(subnodes, key=lambda x: x.uri.lower())

def all_nodes(include_journals=True):
    # first we fetch all subnodes, put them in a dict {wikilink -> [subnode]}.
    # hack hack -- there's something in itertools better than this.
    wikilink_to_subnodes = defaultdict(list)
    for subnode in all_subnodes():
        wikilink_to_subnodes[subnode.wikilink].append(subnode)

    # then we iterate over its values and construct nodes for each list of subnodes.
    nodes = []
    for wikilink in wikilink_to_subnodes:
        node = Node(wikilink)
        node.subnodes = wikilink_to_subnodes[wikilink]
        nodes.append(node)

    # remove journals if so desired.
    if not include_journals:
        nodes = [node for node in nodes if not re.match('[0-9]+?-[0-9]+?-[0-9]+?', node.wikilink)]

    # TODO: experiment with other ranking.
    # return sorted(nodes, key=lambda x: -x.size())
    return sorted(nodes, key=lambda x: x.wikilink.lower())

def all_users():
    # hack hack.
    users = os.listdir(os.path.join(config.AGORA_PATH, 'garden'))
    return sorted([User(u) for u in users], key=lambda x: x.uri.lower())

def all_journals():
    # hack hack.
    nodes = all_nodes()
    nodes = [node for node in nodes if re.match('[0-9]+?-[0-9]+?-[0-9]+?', node.wikilink)]
    return sorted(nodes, key=attrgetter('wikilink'), reverse=True)

def nodes_by_wikilink(wikilink):
    nodes = [node for node in all_nodes() if node.wikilink == wikilink]
    return nodes

def subnodes_by_wikilink(wikilink, fuzzy_matching=True):
    if fuzzy_matching:
        # TODO
        subnodes = [subnode for subnode in all_subnodes() if fuzz.ratio(subnode.wikilink, wikilink) > FUZZ_FACTOR]
    else:
        subnodes = [subnode for subnode in all_subnodes() if subnode.wikilink == wikilink]
    return subnodes

def subnodes_by_user(user):
    subnodes = [subnode for subnode in all_subnodes() if subnode.user == user]
    return subnodes

def subnode_by_uri(uri):
    subnode = [subnode for subnode in all_subnodes() if subnode.uri == uri][0]
    return subnode

def nodes_by_outlink(wikilink):
    nodes = [node for node in all_nodes() if wikilink in node.outlinks]
    return nodes

def subnodes_by_outlink(wikilink):
    # This doesn't work. It matches too much/too little for some reason. Debug someday?
    # subnodes = [subnode for subnode in all_subnodes() if [wikilink for wikilink in subnode.outlinks if fuzz.ratio(subnode.wikilink, wikilink) > FUZZ_FACTOR]]
    subnodes = [subnode for subnode in all_subnodes() if util.canonical_wikilink(wikilink) in subnode.outlinks]
    return subnodes