from typing import Optional, List
from sqlmodel import SQLModel, Field, Relationship
from datetime import datetime
from enum import Enum


class SnippetVisibility(str, Enum):
    PRIVATE = "private"
    DEPARTMENT = "department"
    ORGANIZATION = "organization"


class Language(SQLModel, table=True):
    __tablename__ = "language"

    id: Optional[int] = Field(default=None, primary_key=True)
    code: str = Field(unique=True, index=True)
    name: str
    is_default: bool = Field(default=False)
    created_at: datetime = Field(default_factory=datetime.utcnow)

    translations: List["Translation"] = Relationship(back_populates="language")


class Translation(SQLModel, table=True):
    __tablename__ = "translation"

    id: Optional[int] = Field(default=None, primary_key=True)
    key: str = Field(index=True)
    value: str = Field(default="")
    language_id: int = Field(foreign_key="language.id")
    created_at: datetime = Field(default_factory=datetime.utcnow)
    updated_at: datetime = Field(default_factory=datetime.utcnow)

    language: Language = Relationship(back_populates="translations")


# Association table for User-Department many-to-many relationship
class UserDepartmentLink(SQLModel, table=True):
    __tablename__ = "user_department"
    
    user_id: Optional[int] = Field(default=None, foreign_key="user.id", primary_key=True)
    department_id: Optional[int] = Field(default=None, foreign_key="department.id", primary_key=True)


# Association table for Snippet-Department access control
class SnippetDepartmentLink(SQLModel, table=True):
    __tablename__ = "snippet_department"
    
    snippet_id: Optional[int] = Field(default=None, foreign_key="snippet.id", primary_key=True)
    department_id: Optional[int] = Field(default=None, foreign_key="department.id", primary_key=True)
    enabled: bool = Field(default=True)  # Can be toggled by admins
    created_at: datetime = Field(default_factory=datetime.utcnow)


class User(SQLModel, table=True):
    __tablename__ = "user"
    
    id: Optional[int] = Field(default=None, primary_key=True)
    username: str = Field(unique=True, index=True)
    email: str = Field(unique=True, index=True)
    hashed_password: str
    full_name: Optional[str] = None
    profile_picture: Optional[str] = None
    theme: str = Field(default="light")  # 'light' or 'dark'
    is_active: bool = Field(default=True)
    is_admin: bool = Field(default=False)
    created_at: datetime = Field(default_factory=datetime.utcnow)
    
    # Relationships
    departments: List["Department"] = Relationship(back_populates="users", link_model=UserDepartmentLink)
    messages: List["Message"] = Relationship(back_populates="sender")
    snippets: List["Snippet"] = Relationship(back_populates="owner")
    sent_direct_messages: List["DirectMessage"] = Relationship(back_populates="sender", sa_relationship_kwargs={"foreign_keys": "DirectMessage.sender_id"})
    received_direct_messages: List["DirectMessage"] = Relationship(back_populates="receiver", sa_relationship_kwargs={"foreign_keys": "DirectMessage.receiver_id"})
    uploaded_files: List["FileAttachment"] = Relationship(back_populates="uploader")
    file_permissions: List["FilePermission"] = Relationship(back_populates="user")


class Department(SQLModel, table=True):
    __tablename__ = "department"
    
    id: Optional[int] = Field(default=None, primary_key=True)
    name: str = Field(unique=True, index=True)
    description: Optional[str] = None
    snippets_enabled: bool = Field(default=True)  # Master switch for snippet access
    created_at: datetime = Field(default_factory=datetime.utcnow)
    
    # Relationships
    users: List[User] = Relationship(back_populates="departments", link_model=UserDepartmentLink)
    channels: List["Channel"] = Relationship(back_populates="department")
    allowed_snippets: List["Snippet"] = Relationship(link_model=SnippetDepartmentLink)


class Channel(SQLModel, table=True):
    __tablename__ = "channel"
    
    id: Optional[int] = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    description: Optional[str] = None
    department_id: int = Field(foreign_key="department.id")
    created_at: datetime = Field(default_factory=datetime.utcnow)
    
    # Relationships
    department: Department = Relationship(back_populates="channels")
    messages: List["Message"] = Relationship(back_populates="channel")


class Message(SQLModel, table=True):
    __tablename__ = "message"
    
    id: Optional[int] = Field(default=None, primary_key=True)
    content: str
    sender_id: int = Field(foreign_key="user.id")
    channel_id: int = Field(foreign_key="channel.id")
    snippet_id: Optional[int] = Field(default=None, foreign_key="snippet.id")
    reply_to_id: Optional[int] = Field(default=None, foreign_key="message.id")  # Reply to another message
    is_deleted: bool = Field(default=False)
    created_at: datetime = Field(default_factory=datetime.utcnow)
    
    # Relationships
    sender: User = Relationship(back_populates="messages")
    channel: Channel = Relationship(back_populates="messages")
    attachments: List["FileAttachment"] = Relationship(back_populates="message")
    snippet: Optional["Snippet"] = Relationship()


class DirectMessage(SQLModel, table=True):
    __tablename__ = "direct_message"
    
    id: Optional[int] = Field(default=None, primary_key=True)
    content: str
    sender_id: int = Field(foreign_key="user.id")
    receiver_id: int = Field(foreign_key="user.id")
    snippet_id: Optional[int] = Field(default=None, foreign_key="snippet.id")
    reply_to_id: Optional[int] = Field(default=None, foreign_key="direct_message.id")  # Reply to another DM
    created_at: datetime = Field(default_factory=datetime.utcnow)
    is_read: bool = Field(default=False)
    
    # Relationships
    sender: User = Relationship(back_populates="sent_direct_messages", sa_relationship_kwargs={"foreign_keys": "DirectMessage.sender_id"})
    receiver: User = Relationship(back_populates="received_direct_messages", sa_relationship_kwargs={"foreign_keys": "DirectMessage.receiver_id"})
    snippet: Optional["Snippet"] = Relationship()


class FileAttachment(SQLModel, table=True):
    __tablename__ = "file_attachment"
    
    id: Optional[int] = Field(default=None, primary_key=True)
    filename: str
    original_filename: str
    mime_type: str
    file_size: int
    file_path: str
    message_id: int = Field(foreign_key="message.id")
    uploader_id: Optional[int] = Field(default=None, foreign_key="user.id")
    webdav_path: Optional[str] = None
    upload_permission: str = Field(default="read")  # "read" or "write"
    is_editable: bool = Field(default=False)
    uploaded_at: datetime = Field(default_factory=datetime.utcnow)
    
    # Relationships
    message: Message = Relationship(back_populates="attachments")
    uploader: Optional[User] = Relationship(back_populates="uploaded_files")
    permissions: List["FilePermission"] = Relationship(back_populates="file")


class FilePermission(SQLModel, table=True):
    __tablename__ = "file_permission"
    
    id: Optional[int] = Field(default=None, primary_key=True)
    file_id: int = Field(foreign_key="file_attachment.id")
    user_id: int = Field(foreign_key="user.id")
    permission: str = Field(default="read")  # "read" or "write"
    granted_at: datetime = Field(default_factory=datetime.utcnow)
    
    # Relationships
    file: FileAttachment = Relationship(back_populates="permissions")
    user: User = Relationship(back_populates="file_permissions")


class Snippet(SQLModel, table=True):
    __tablename__ = "snippet"
    
    id: Optional[int] = Field(default=None, primary_key=True)
    title: str = Field(index=True)
    language: str = Field(index=True)
    content: str
    tags: Optional[str] = None  # Comma-separated
    visibility: SnippetVisibility = Field(default=SnippetVisibility.PRIVATE)
    
    owner_id: int = Field(foreign_key="user.id")
    department_id: Optional[int] = Field(default=None, foreign_key="department.id")
    
    created_at: datetime = Field(default_factory=datetime.utcnow)
    updated_at: datetime = Field(default_factory=datetime.utcnow)
    
    # Relationships
    owner: User = Relationship(back_populates="snippets")
    department: Optional[Department] = Relationship()
    allowed_departments: List["Department"] = Relationship(link_model=SnippetDepartmentLink)