import uuid
from datetime import datetime

from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, String, Text, UniqueConstraint, func
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import Mapped, mapped_column, relationship

from .base import Base


class User(Base):
    __tablename__ = "users"

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    email: Mapped[str] = mapped_column(String(255), unique=True, index=True, nullable=False)
    hashed_password: Mapped[str] = mapped_column(String(255), nullable=False)
    display_name: Mapped[str] = mapped_column(String(100), nullable=False)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())

    songs: Mapped[list["Song"]] = relationship(back_populates="owner", cascade="all, delete-orphan")


class Song(Base):
    __tablename__ = "songs"

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    user_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"))

    title: Mapped[str] = mapped_column(String(200), nullable=False)
    prompt: Mapped[str] = mapped_column(Text, nullable=False)
    lyrics: Mapped[str | None] = mapped_column(Text, nullable=True)
    mode: Mapped[str] = mapped_column(String(20), default="instrumental")  # instrumental | vocals

    status: Mapped[str] = mapped_column(String(20), default="pending")  # pending|processing|completed|failed
    error_message: Mapped[str | None] = mapped_column(Text, nullable=True)

    audio_path: Mapped[str | None] = mapped_column(String(500), nullable=True)
    duration_seconds: Mapped[float | None] = mapped_column(nullable=True)
    cover_seed: Mapped[int] = mapped_column(Integer, default=0)

    is_public: Mapped[bool] = mapped_column(Boolean, default=False)
    like_count: Mapped[int] = mapped_column(Integer, default=0)

    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())

    owner: Mapped["User"] = relationship(back_populates="songs")
    likes: Mapped[list["Like"]] = relationship(back_populates="song", cascade="all, delete-orphan")


class Like(Base):
    __tablename__ = "likes"
    __table_args__ = (UniqueConstraint("user_id", "song_id", name="uq_like_user_song"),)

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    user_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"))
    song_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("songs.id", ondelete="CASCADE"))
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())

    song: Mapped["Song"] = relationship(back_populates="likes")