""""""

import logging
import re
from collections import OrderedDict

import sqlalchemy as sa
import sqlalchemy.exc
import yaml
from six import text_type

from abilian.core.entities import Entity
from abilian.core.models import attachment, comment, tag
from abilian.core.util import slugify
from abilian.services.security import CREATE, DELETE, READ, WRITE, Permission, Role
from abilian.services.vocabularies import Vocabulary, get_vocabulary
from abilian.web.forms import Form, FormPermissions
from abilian.web.tags.extension import ns as tag_ns

from . import autoname
from .fieldtypes import get_field

logger = logging.getLogger(__name__)


def assert_ascii(s):
    try:
        s.encode("ascii")
    except UnicodeError:
        raise ValueError(f"{repr(s)} is not an ASCII string")


class CodeGenerator:
    def __init__(self, yaml_file=None, data=None, **options):
        self.vocabularies = {}
        self.options = options
        self._model_finalizers = []
        if data is not None:
            self.data = data
        else:
            self.load_file(yaml_file)
        self.prepare_data()

    def load_file(self, yaml_file):
        self.data = yaml.load(yaml_file)

    def add_model_finalizer(self, finalizer):
        self._model_finalizers.append(finalizer)

    def set_current_module(self, module):
        self.module = module

    def prepare_data(self):
        """Massage data before models creations."""
        for d in self.data["fields"]:
            vocabulary = d.get("vocabulary")
            if vocabulary:
                name = "Vocabulary_"
                group = vocabulary.get("group", "").strip()
                if group:
                    group = slugify(group, "_")
                    name += group + "__"
                name += vocabulary["name"]

                if name in self.vocabularies:
                    # already defined in another field, maybe on another model: share
                    # existing definition so that generated class is also accessible
                    d["vocabulary"] = self.vocabularies[name]
                else:
                    vocabulary["generated_name"] = name.encode("ascii")
                    self.vocabularies[name] = vocabulary
                continue

            # slugify list items
            from_list = d.get("from_list")
            if from_list is None:
                continue

            key_val_list = []
            seen = dict()
            for item in from_list:
                k = v = item
                if isinstance(item, (list, tuple)):
                    k, v = item
                    if isinstance(k, bytes):
                        k = k.decode("utf-8")
                    v = str(v)
                else:
                    if isinstance(item, bytes):
                        item = item.decode("utf-8")
                    k = str(slugify(item, "_"))

                k = re.sub("[^\\w\\s-]", "", k).strip().upper()
                k = re.sub("[-\\s]+", "_", k)
                #  avoid duplicates: suffix by a number if needed
                current = k
                count = 0
                while k in seen and seen[k] != v:
                    count += 1
                    k = f"{current}_{count}"

                seen[k] = v
                key_val_list.append((k, v))

            d["from_list"] = key_val_list

    def init_vocabularies(self, module):
        self.set_current_module(module)
        for generated_name, definition in self.vocabularies.items():
            name = definition["name"].encode("ascii").strip()
            group = definition.get("group", "").strip() or None
            label = definition["label"].strip()
            voc_cls = get_vocabulary(name, group=group)

            if voc_cls is None:
                voc_cls = Vocabulary(name=name, group=group, label=label)

            definition["cls"] = voc_cls

            if not hasattr(module, generated_name):
                setattr(module, generated_name, voc_cls)

    def gen_model(self, module):
        self.set_current_module(module)
        table_args = self.data.get("table_args", [])
        model_name = self.data["name"]
        type_name = self.data.get("type_name", model_name + "Base")
        type_base = self.data.get("type_base", Entity)
        try:
            type_base_attrs = sa.inspect(type_base).attrs
        except sa.exc.NoInspectionAvailable:
            type_base_attrs = frozenset()

        attributes = OrderedDict(self.data.get("attributes", {}))
        attributes["__module__"] = module.__name__
        attributes["__tablename__"] = self.data.get("tablename", model_name.lower())

        # default permissions
        permissions = self.data.get("permissions")
        if permissions:
            default_permissions = {}
            for perm, roles in permissions.items():
                perm = perm.strip()
                if not perm:
                    raise TypeError("Found empty string for permission")
                perm = Permission(perm)
                roles = {Role(r.strip()) for r in roles if r.strip()}

                if not roles:
                    continue

                default_permissions[perm] = roles
        else:
            default_permissions = self.options.get("default_permissions", {})

        if default_permissions:
            for p in (WRITE, CREATE, DELETE):
                if p in default_permissions:
                    read_permissions = default_permissions.setdefault(READ, set())
                    read_permissions |= default_permissions[p]

            if WRITE in default_permissions:
                for p in (CREATE, DELETE):
                    if p not in default_permissions:
                        default_permissions[p] = set(default_permissions[WRITE])

            attributes["__default_permissions__"] = default_permissions

        # Fields
        for d in self.data["fields"]:
            if "ignore" in d:
                continue

            type_ = d["type"]
            if type_ == "pass":
                # explicit manual handling - only declared in form groups
                continue

            FieldCls = get_field(type_)
            if FieldCls is None:
                raise ValueError(f"Unknown type: {repr(type_)}")

            field = FieldCls(model=model_name, data=d, generator=self)

            if d["name"] in type_base_attrs:
                # existing field (i.e, Entity.name), don't override column else it will
                # be duplicated in joined table, and missing some setup found in
                # overriden column (like indexability)
                #
                # since field has been setup, it has created 'formfield' instance,
                # required for form generation
                continue

            for name, attr in field.get_model_attributes():
                assert name not in attributes
                attributes[name] = attr

            for arg in field.get_table_args():
                table_args.append(arg)

        for finalize in self._model_finalizers:
            finalize(attributes, table_args, module)

        if table_args:
            attributes["__table_args__"] = tuple(table_args)

        cls = type(type_name, (type_base,), attributes)
        self.data["cls"] = cls
        setattr(module, type_name, cls)

        # automatic name from other fields
        auto_name = str(self.data.get("auto_name") or "").strip()

        if auto_name:
            autoname.setup(cls, auto_name)

        # commentable?
        if self.data.get("commentable", False):
            comment.register(cls)

        # attachments support ?
        if self.data.get("attachments", False):
            attachment.register(cls)

        # tagging support ?
        cls_tags_ns = self.data.get("tag")
        if cls_tags_ns:
            tag.register(cls)
            tag_ns(cls_tags_ns)(cls)

        return cls

    def gen_form(self, module):
        self.set_current_module(module)
        type_name = self.data["name"] + "EditFormBase"
        type_bases = (Form,)
        attributes = OrderedDict()

        groups = {}
        group_names = []
        read_permissions = {}
        write_permissions = {}

        for d in self.data["fields"]:
            if "ignore" in d or "hidden" in d:
                continue

            field_name = d["name"]

            if "ignore" not in d:
                group_name = d.get("group", "default group")
                groups.setdefault(group_name, []).append(field_name)
                if group_name not in group_names:
                    group_names.append(group_name)

                perms = d.get("permissions", {})
                write = {Role(r.strip()) for r in perms.get("write", ())}
                read = write | {Role(r.strip()) for r in perms.get("read", ())}
                if write:
                    write_permissions[field_name] = write
                if read:
                    read_permissions[field_name] = read

            if d["type"] == "pass":
                # explicit manual handling - only declared in form groups
                continue

            field = d["formfield"]
            for name, attr in field.get_form_attributes():
                attributes[name] = attr

        attributes["_permissions"] = FormPermissions(
            fields_read=read_permissions, fields_write=write_permissions
        )
        attributes["_groups"] = OrderedDict(
            (name, groups[name]) for name in group_names
        )
        attributes["__module__"] = module.__name__
        cls = type(type_name, type_bases, attributes)
        setattr(module, type_name, cls)
        return cls
