from __future__ import annotations

import typing
from typing import Any, Dict, List, Optional, Tuple, Type, Union

from django.db import models
from django.db.models import Q
from .fluent import FluentQuery


class classproperty:
    def __init__(self, func):
        self.fget = func

    def __get__(self, obj, objtype=None):
        return self.fget(objtype if objtype is not None else type(obj))


ABBREVIATIONS = {
    'uuid': 'UUID',
    'id': 'ID',
    'ip': 'IP',
    'url': 'URL',
    'uri': 'URI',
    'api': 'API',
    'html': 'HTML',
    'css': 'CSS',
    'js': 'JS',
    'json': 'JSON',
    'xml': 'XML',
    'sql': 'SQL',
    'http': 'HTTP',
    'https': 'HTTPS',
    'smtp': 'SMTP',
    'ssl': 'SSL',
    'tls': 'TLS',
    'ssh': 'SSH',
    'ftp': 'FTP',
    '2fa': '2FA',
    'elt': 'ELT',
    'sve': 'SVE',
    't4': 'T4',
    'mc': 'MC',
    'crb': 'CRB',
    'ccgo': 'CCGO',
    'ugm': 'UGM',
    'gerp': 'GERP',
    'abac': 'ABAC',
    'rbac': 'RBAC',
    'smtm': 'SMTM',
    'pwd': 'PWD',
}


def snake_to_pascal(name):
    if '_' not in name:
        return name[0].upper() + name[1:] if name else name
    parts = name.split('_')
    result = []
    for p in parts:
        lower = p.lower()
        if lower in ABBREVIATIONS:
            result.append(ABBREVIATIONS[lower])
        else:
            result.append(p.capitalize())
    return ''.join(result)


def pascal_to_snake(name):
    import re
    s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
    s2 = re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1)
    parts = s2.lower().split('_')
    return '_'.join(parts)


class _InvertedFieldExpression:
    def __init__(self, field_expr):
        self._field_expr = field_expr

    def startswith(self, value):
        return ~Q(**{f'{self._field_expr._django_name}__startswith': value})

    def contains(self, value):
        return ~Q(**{f'{self._field_expr._django_name}__contains': value})

    def like(self, pattern):
        clean = pattern.strip('%')
        return ~Q(**{f'{self._field_expr._django_name}__icontains': clean})

    def in_(self, values):
        return ~Q(**{f'{self._field_expr._django_name}__in': values})

    def is_(self, other):
        if other is None:
            return ~Q(**{f'{self._field_expr._django_name}__isnull': True})
        return ~Q(**{self._field_expr._django_name: other})


class FieldExpression:
    _resolve_cache = {}

    def __init__(self, model_class, field_name):
        self.model_class = model_class
        self.field_name = field_name
        self._django_name = self._resolve_django_name()

    def _resolve_django_name(self):
        cache_key = (self.model_class.__name__, self.field_name)
        if cache_key in FieldExpression._resolve_cache:
            return FieldExpression._resolve_cache[cache_key]
        if hasattr(self.model_class, '_meta'):
            for f in self.model_class._meta.local_fields:
                if f.name == self.field_name:
                    FieldExpression._resolve_cache[cache_key] = f.name
                    return f.name
        FieldExpression._resolve_cache[cache_key] = self.field_name
        return self.field_name

    def __eq__(self, other):
        if isinstance(other, FieldExpression):
            return NotImplemented
        if other is None:
            return Q(**{f'{self._django_name}__isnull': True})
        return Q(**{self._django_name: other})

    def __ne__(self, other):
        if isinstance(other, FieldExpression):
            return NotImplemented
        return ~Q(**{self._django_name: other})

    def __gt__(self, other):
        return Q(**{f'{self._django_name}__gt': other})

    def __ge__(self, other):
        return Q(**{f'{self._django_name}__gte': other})

    def __lt__(self, other):
        return Q(**{f'{self._django_name}__lt': other})

    def __le__(self, other):
        return Q(**{f'{self._django_name}__lte': other})

    def __getitem__(self, key):
        return _JsonKeyExpression(self._django_name, key)

    def __hash__(self):
        return hash((self.model_class.__name__, self.field_name))

    def __and__(self, other):
        if isinstance(other, Q):
            return Q(self) & other
        return NotImplemented

    def __or__(self, other):
        if isinstance(other, Q):
            return Q(self) | other
        return NotImplemented

    def __invert__(self):
        return _InvertedFieldExpression(self)

    def is_(self, other):
        if other is None:
            return Q(**{f'{self._django_name}__isnull': True})
        return Q(**{self._django_name: other})

    def is_not(self, other):
        if other is None:
            return Q(**{f'{self._django_name}__isnull': False})
        return ~Q(**{self._django_name: other})

    def like(self, pattern):
        clean = pattern.strip('%')
        return Q(**{f'{self._django_name}__icontains': clean})

    def contains(self, value):
        return Q(**{f'{self._django_name}__contains': value})

    def ilike(self, pattern):
        return self.like(pattern)

    def startswith(self, value):
        return Q(**{f'{self._django_name}__startswith': value})

    def istartswith(self, value):
        return Q(**{f'{self._django_name}__istartswith': value})

    def endswith(self, value):
        return Q(**{f'{self._django_name}__endswith': value})

    def iendswith(self, value):
        return Q(**{f'{self._django_name}__iendswith': value})

    def in_(self, values):
        if hasattr(values, '_qs'):
            return Q(**{f'{self._django_name}__in': values._qs.values(self._django_name)})
        return Q(**{f'{self._django_name}__in': values})

    def between(self, low, high):
        return Q(**{f'{self._django_name}__gte': low}) & Q(**{f'{self._django_name}__lte': high})

    def regex(self, pattern):
        return Q(**{f'{self._django_name}__regex': pattern})

    def iregex(self, pattern):
        return Q(**{f'{self._django_name}__iregex': pattern})

    def desc(self):
        return f'-{self._django_name}'

    def asc(self):
        return self._django_name

    def __repr__(self):
        return f'FieldExpr({self.model_class.__name__}.{self.field_name})'

    def __str__(self):
        return self._django_name


class _JsonKeyExpression:
    def __init__(self, field_name, key):
        self.field_name = field_name
        self.key = key

    def _lookup(self, suffix=''):
        if suffix:
            return f'{self.field_name}__{self.key}__{suffix}'
        return f'{self.field_name}__{self.key}'

    def cast(self, type_hint):
        return _CastJsonExpression(self.field_name, self.key, type_hint)

    def __eq__(self, other):
        return Q(**{self._lookup(): other})

    def __ne__(self, other):
        return ~Q(**{self._lookup(): other})

    def __gt__(self, other):
        return Q(**{self._lookup('gt'): other})

    def __ge__(self, other):
        return Q(**{self._lookup('gte'): other})

    def __lt__(self, other):
        return Q(**{self._lookup('lt'): other})

    def __le__(self, other):
        return Q(**{self._lookup('lte'): other})

    def between(self, low, high):
        return Q(**{self._lookup('gte'): low}) & Q(**{self._lookup('lte'): high})

    def __repr__(self):
        return f'JsonKeyExpr({self.field_name}[{self.key!r}])'


class _CastJsonExpression:
    def __init__(self, field_name, key, type_hint):
        self.field_name = field_name
        self.key = key
        self.type_hint = type_hint

    def _lookup(self, suffix=''):
        if suffix:
            return f'{self.field_name}__{self.key}__{suffix}'
        return f'{self.field_name}__{self.key}'

    def between(self, low, high):
        return Q(**{self._lookup('gte'): low}) & Q(**{self._lookup('lte'): high})

    def __eq__(self, other):
        return Q(**{self._lookup(): other})

    def __ne__(self, other):
        return ~Q(**{self._lookup(): other})

    def __gt__(self, other):
        return Q(**{self._lookup('gt'): other})

    def __ge__(self, other):
        return Q(**{self._lookup('gte'): other})

    def __lt__(self, other):
        return Q(**{self._lookup('lt'): other})

    def __le__(self, other):
        return Q(**{self._lookup('lte'): other})

    def __repr__(self):
        type_name = getattr(self.type_hint, '__name__', str(self.type_hint))
        return f'CastJsonExpr({self.field_name}[{self.key!r}]->{type_name})'


class ForeignKeyIdDescriptor:
    """FK 字段描述符：类级别访问返回 FieldExpression，实例级别访问/设置委托给原始 Django 字段。"""
    def __init__(self, fk_name):
        self.fk_name = fk_name
        self.id_attr = fk_name + '_id'
        self._original_field = None  # 延迟绑定原始 Django 字段

    def _get_original_field(self, owner):
        if self._original_field is None:
            try:
                self._original_field = owner._meta.get_field(self.fk_name)
            except Exception:
                pass
        return self._original_field

    def __get__(self, obj, objtype=None):
        if obj is None:
            return FieldExpression(objtype, self.id_attr)
        return getattr(obj, self.id_attr)

    def __set__(self, obj, value):
        # 直接写入实例 __dict__，避免触发描述符递归
        obj.__dict__[self.id_attr] = value


class FieldExpressionDescriptor:
    """普通字段描述符：类级别访问返回 FieldExpression，实例级别访问/设置委托给原始 Django 字段。"""
    def __init__(self, field_name):
        self.field_name = field_name
        self._original_field = None  # 延迟绑定原始 Django 字段

    def _get_original_field(self, owner):
        if self._original_field is None:
            try:
                self._original_field = owner._meta.get_field(self.field_name)
            except Exception:
                pass
        return self._original_field

    def __get__(self, obj, objtype=None):
        if obj is None:
            return FieldExpression(objtype, self.field_name)
        # 实例级别：从 __dict__ 获取，或让 Django 字段描述符处理
        if self.field_name in obj.__dict__:
            return obj.__dict__[self.field_name]
        # 委托给原始 Django 字段
        orig = self._get_original_field(objtype)
        if orig is not None:
            return orig.__get__(obj, objtype)
        return getattr(obj, self.field_name)

    def __set__(self, obj, value):
        # 直接写入实例 __dict__，避免触发描述符递归
        obj.__dict__[self.field_name] = value


class QModelBase(models.base.ModelBase):
    def __new__(mcs, name, bases, namespace, **kwargs):
        # 不再强制设置 db_column —— Django 会自动处理

        # 动态设置 managed：子服务器可设 GVSDSDK_MANAGE_TABLES=True 让 gvsdsdk 管理表
        meta = namespace.get('Meta')
        if meta and getattr(meta, 'app_label', None) == 'gvsdsdk':
            try:
                from django.conf import settings
                if getattr(settings, 'GVSDSDK_MANAGE_TABLES', False):
                    meta.managed = True
            except Exception:
                pass

        cls = super().__new__(mcs, name, bases, namespace, **kwargs)

        # 模型创建后，包装字段描述符以支持类级别 FieldExpression
        if not cls._meta.abstract:
            _wrap_field_descriptors(cls)

        return cls


def _wrap_field_descriptors(cls: Type) -> None:
    """包装 Django 字段描述符，使类级别访问返回 FieldExpression，
    实例级别完全委托给 Django 原生描述符。

    Django 的字段描述符（DeferredAttribute / ForwardManyToOneDescriptor）：
    - __get__(None, cls) → 返回字段对象本身（类级别）
    - __get__(instance, cls) → 返回字段值（实例级别）

    我们包装后：
    - __get__(None, cls) → 返回 FieldExpression（类级别，用于链式 OOP）
    - __get__(instance, cls) → 委托给原生描述符（实例级别，正常行为）
    """
    from django.db.models.query_utils import DeferredAttribute
    from django.db.models.fields.related_descriptors import (
        ForwardManyToOneDescriptor,
        ForwardOneToOneDescriptor,
    )

    for field in cls._meta.local_fields:
        fname = field.name
        if fname.startswith('_'):
            continue

        original_desc = cls.__dict__.get(fname)
        if original_desc is None:
            continue

        # 只包装已知的 Django 描述符类型
        if isinstance(original_desc, (DeferredAttribute, ForwardManyToOneDescriptor,
                                       ForwardOneToOneDescriptor)):
            wrapper = _FieldExpressionWrapper(original_desc, cls, fname)
            setattr(cls, fname, wrapper)


class _FieldExpressionWrapper:
    """包装 Django 字段描述符，类级别返回 FieldExpression，实例级别委托给原生描述符。"""

    def __init__(self, original_descriptor, model_class, field_name):
        self._original = original_descriptor
        self._model = model_class
        self._field_name = field_name
        self._has_set = hasattr(original_descriptor, '__set__')

    def __get__(self, obj, objtype=None):
        if obj is None:
            # 类级别访问：返回 FieldExpression
            return FieldExpression(self._model, self._field_name)
        # 实例级别访问：委托给原生 Django 描述符
        return self._original.__get__(obj, objtype)

    def __set__(self, obj, value):
        if self._has_set:
            # FK/O2O 描述符有 __set__
            self._original.__set__(obj, value)
        else:
            # 普通字段（DeferredAttribute）没有 __set__，直接写 __dict__
            obj.__dict__[self._field_name] = value


class QModel(models.Model, metaclass=QModelBase):
    """QModel 兼容层基类，提供 SQLAlchemy 风格的链式 OOP 查询接口。

    所有继承 QModel 的模型自动获得：
    - ``Model.query`` : 返回 FluentQuery，支持链式查询
    - ``Model.field_name`` : 类级别访问返回 FieldExpression，支持表达式查询
    - ``Model.field_name`` : 实例级别访问返回字段值（与普通 Django Model 一致）

    用法示例::

        # 链式查询
        orders = Dingdan.query.filter(zhuangtai=8).order_by('-create_time').to_list()

        # 字段表达式
        Dingdan.query.filter(Dingdan.jine > 100, Dingdan.zhuangtai.in_([1,2,3]))

        # 聚合
        Dingdan.query.aggregate(total=Sum('jine'))

        # values / annotate
        Dingdan.query.values('zhuangtai').annotate(cnt=Count('id'))

        # 分页
        Dingdan.query.paginate(page=1, per_page=20)
    """

    class Meta:
        abstract = True

    @classproperty
    def query(cls) -> FluentQuery:
        """返回 FluentQuery 兼容层查询构建器，支持链式 OOP 查询。"""
        return FluentQuery(cls)

    @classmethod
    def __class_getitem__(cls, item) -> FluentQuery:
        """支持 Model[condition] 语法，返回 filter 后的 FluentQuery。

        用法::

            Dingdan[Dingdan.zhuangtai == 8].order_by('-create_time').to_list()
        """
        if isinstance(item, Q):
            return cls.query.filter(item)
        if isinstance(item, dict):
            return cls.query.filter(**item)
        return cls.query.filter(item)