import uuid
from datetime import datetime

from sqlalchemy import (
    Boolean,
    Column,
    DateTime,
    Enum,
    ForeignKey,
    Index,
    Integer,
    String,
    Table,
    Text,
)
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func

from db.database import Base


def _uuid() -> str:
    return str(uuid.uuid4())


# ── Many-to-many: Conversation ↔ Contact ──────────────────────────────────────
conversation_participants = Table(
    "conversation_participants",
    Base.metadata,
    Column("conversation_id", String, ForeignKey("conversations.id", ondelete="CASCADE")),
    Column("contact_id", String, ForeignKey("contacts.id", ondelete="CASCADE")),
)


# ── Contact ────────────────────────────────────────────────────────────────────
class Contact(Base):
    __tablename__ = "contacts"

    id = Column(String, primary_key=True, default=_uuid)
    name = Column(String(255), nullable=False, index=True)
    phone = Column(String(32), nullable=True, unique=True)
    email = Column(String(255), nullable=True)
    telegram_id = Column(String(64), nullable=True, unique=True)
    telegram_username = Column(String(255), nullable=True)
    whatsapp_phone = Column(String(32), nullable=True)
    notes = Column(Text, nullable=True)
    created_at = Column(DateTime, default=func.now(), nullable=False)
    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())

    conversations = relationship(
        "Conversation",
        secondary=conversation_participants,
        back_populates="participants",
    )
    messages_sent = relationship(
        "Message",
        back_populates="sender",
        foreign_keys="Message.sender_id",
    )


# ── Conversation ───────────────────────────────────────────────────────────────
class Conversation(Base):
    __tablename__ = "conversations"

    id = Column(String, primary_key=True, default=_uuid)
    channel = Column(
        Enum("telegram", "whatsapp", "sms", name="channel_type"),
        nullable=False,
        index=True,
    )
    channel_conversation_id = Column(String(255), nullable=True)
    title = Column(String(255), nullable=True)
    is_group = Column(Boolean, default=False, nullable=False)
    is_archived = Column(Boolean, default=False, nullable=False)
    last_message_at = Column(DateTime, nullable=True)
    created_at = Column(DateTime, default=func.now(), nullable=False)
    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())

    participants = relationship(
        "Contact",
        secondary=conversation_participants,
        back_populates="conversations",
    )
    messages = relationship(
        "Message",
        back_populates="conversation",
        cascade="all, delete-orphan",
        order_by="Message.created_at",
    )

    __table_args__ = (
        Index("idx_conv_channel_native", "channel", "channel_conversation_id"),
    )


# ── Message ────────────────────────────────────────────────────────────────────
class Message(Base):
    __tablename__ = "messages"

    id = Column(String, primary_key=True, default=_uuid)
    conversation_id = Column(
        String, ForeignKey("conversations.id", ondelete="CASCADE"), nullable=False, index=True
    )
    sender_id = Column(String, ForeignKey("contacts.id"), nullable=True)

    channel = Column(
        Enum("telegram", "whatsapp", "sms", name="channel_type"),
        nullable=False,
        index=True,
    )
    channel_message_id = Column(String(255), nullable=True)
    direction = Column(
        Enum("inbound", "outbound", name="message_direction"),
        nullable=False,
        default="outbound",
    )
    text = Column(Text, nullable=False)
    status = Column(
        Enum("pending", "sent", "delivered", "read", "failed", name="message_status"),
        default="pending",
        nullable=False,
        index=True,
    )

    reply_to_id = Column(String, ForeignKey("messages.id"), nullable=True)
    is_edited = Column(Boolean, default=False, nullable=False)
    error_message = Column(Text, nullable=True)
    retry_count = Column(Integer, default=0, nullable=False)

    created_at = Column(DateTime, default=func.now(), nullable=False, index=True)
    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())
    sent_at = Column(DateTime, nullable=True)
    delivered_at = Column(DateTime, nullable=True)
    read_at = Column(DateTime, nullable=True)

    conversation = relationship("Conversation", back_populates="messages")
    sender = relationship("Contact", back_populates="messages_sent", foreign_keys=[sender_id])
    reply_to = relationship("Message", remote_side="Message.id", backref="replies")

    __table_args__ = (
        Index("idx_msg_channel_native", "channel", "channel_message_id"),
        Index("idx_msg_conv_created", "conversation_id", "created_at"),
    )