from datetime import date, datetime, time
from uuid import uuid4

from sqlalchemy import (
    JSON,
    Boolean,
    Date,
    DateTime,
    Float,
    ForeignKey,
    Integer,
    String,
    Text,
    Time,
    UniqueConstraint,
    func,
)
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship


class Base(DeclarativeBase):
    """Declarative base."""


class User(Base):
    """User entity."""

    __tablename__ = "users"

    id: Mapped[str] = mapped_column(String(255), primary_key=True)
    name: Mapped[str] = mapped_column(String(255), nullable=False)
    avatar_url: Mapped[str | None] = mapped_column(String(500))
    provider: Mapped[str] = mapped_column(String(50), nullable=False)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now()
    )

    stories: Mapped[list["Story"]] = relationship(
        "Story", back_populates="user", cascade="all, delete-orphan"
    )
    child_profiles: Mapped[list["ChildProfile"]] = relationship(
        "ChildProfile", back_populates="user", cascade="all, delete-orphan"
    )


class Story(Base):
    """Story entity."""

    __tablename__ = "stories"

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    user_id: Mapped[str] = mapped_column(
        String(255), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    child_profile_id: Mapped[str | None] = mapped_column(
        String(36), ForeignKey("child_profiles.id", ondelete="SET NULL"), nullable=True
    )
    universe_id: Mapped[str | None] = mapped_column(
        String(36), ForeignKey("story_universes.id", ondelete="SET NULL"), nullable=True
    )
    title: Mapped[str] = mapped_column(String(255), nullable=False)
    story_text: Mapped[str | None] = mapped_column(Text, nullable=True)
    pages: Mapped[list[dict] | None] = mapped_column(JSON, default=list)
    cover_prompt: Mapped[str | None] = mapped_column(Text)
    image_url: Mapped[str | None] = mapped_column(String(500))
    mode: Mapped[str] = mapped_column(String(20), nullable=False, default="generated")
    generation_status: Mapped[str] = mapped_column(
        String(32), nullable=False, default="narrative_ready"
    )
    text_status: Mapped[str] = mapped_column(
        String(32), nullable=False, default="ready"
    )
    image_status: Mapped[str] = mapped_column(
        String(32), nullable=False, default="not_requested"
    )
    audio_status: Mapped[str] = mapped_column(
        String(32), nullable=False, default="not_requested"
    )
    audio_path: Mapped[str | None] = mapped_column(String(500))
    last_error: Mapped[str | None] = mapped_column(Text)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now()
    )

    user: Mapped["User"] = relationship("User", back_populates="stories")
    child_profile: Mapped["ChildProfile | None"] = relationship("ChildProfile")
    story_universe: Mapped["StoryUniverse | None"] = relationship("StoryUniverse")

    @property
    def retryable_assets(self) -> list[str]:
        """Assets that can be completed or retried from the current persisted state."""

        assets: list[str] = []

        image_is_busy_or_ready = self.image_status in {"ready", "generating"}
        if not image_is_busy_or_ready:
            if self.mode == "storybook":
                pages = self.pages or []
                has_missing_page_image = any(
                    isinstance(page, dict)
                    and page.get("image_prompt")
                    and not page.get("image_url")
                    for page in pages
                )
                if (self.cover_prompt and not self.image_url) or has_missing_page_image:
                    assets.append("image")
            elif self.cover_prompt:
                assets.append("image")

        audio_is_busy_or_ready = self.audio_status in {"ready", "generating"}
        if self.story_text and not audio_is_busy_or_ready:
            assets.append("audio")

        return assets


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


class GenerationJob(Base):
    """User-visible generation attempt that can be inspected after the request returns."""

    __tablename__ = "generation_jobs"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    user_id: Mapped[str] = mapped_column(
        String(255), ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
    )
    story_id: Mapped[int | None] = mapped_column(
        Integer, ForeignKey("stories.id", ondelete="SET NULL"), nullable=True, index=True
    )
    output_mode: Mapped[str] = mapped_column(String(32), nullable=False)
    input_type: Mapped[str] = mapped_column(String(32), nullable=False)
    status: Mapped[str] = mapped_column(String(32), nullable=False, default="running", index=True)
    current_step: Mapped[str] = mapped_column(
        String(64), nullable=False, default="request_accepted"
    )
    request_payload: Mapped[dict] = mapped_column(JSON, default=dict)
    result_snapshot: Mapped[dict] = mapped_column(JSON, default=dict)
    error_message: Mapped[str | None] = mapped_column(Text)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), index=True
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), onupdate=func.now()
    )


class GenerationJobEvent(Base):
    """Append-only event emitted by a generation job."""

    __tablename__ = "generation_job_events"

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    job_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("generation_jobs.id", ondelete="CASCADE"), nullable=False, index=True
    )
    story_id: Mapped[int | None] = mapped_column(
        Integer, ForeignKey("stories.id", ondelete="SET NULL"), nullable=True, index=True
    )
    event_type: Mapped[str] = mapped_column(String(64), nullable=False)
    status: Mapped[str] = mapped_column(String(32), nullable=False)
    message: Mapped[str | None] = mapped_column(Text)
    event_metadata: Mapped[dict] = mapped_column(JSON, default=dict)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), index=True
    )


class ChildProfile(Base):
    """Child profile entity."""

    __tablename__ = "child_profiles"
    __table_args__ = (UniqueConstraint("user_id", "name", name="uq_child_profile_user_name"),)

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    user_id: Mapped[str] = mapped_column(
        String(255), ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
    )
    name: Mapped[str] = mapped_column(String(50), nullable=False)
    avatar_url: Mapped[str | None] = mapped_column(String(500))
    birth_date: Mapped[date | None] = mapped_column(Date)
    gender: Mapped[str | None] = mapped_column(String(10))

    interests: Mapped[list[str]] = mapped_column(JSON, default=list)
    growth_themes: Mapped[list[str]] = mapped_column(JSON, default=list)
    reading_preferences: Mapped[dict] = mapped_column(JSON, default=dict)

    stories_count: Mapped[int] = mapped_column(Integer, default=0)
    total_reading_time: 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()
    )

    user: Mapped["User"] = relationship("User", back_populates="child_profiles")
    story_universes: Mapped[list["StoryUniverse"]] = relationship(
        "StoryUniverse", back_populates="child_profile", cascade="all, delete-orphan"
    )

    @property
    def age(self) -> int | None:
        if not self.birth_date:
            return None
        today = date.today()
        return today.year - self.birth_date.year - (
            (today.month, today.day) < (self.birth_date.month, self.birth_date.day)
        )


class StoryUniverse(Base):
    """Story universe entity."""

    __tablename__ = "story_universes"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    child_profile_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("child_profiles.id", ondelete="CASCADE"), nullable=False, index=True
    )
    name: Mapped[str] = mapped_column(String(100), nullable=False)
    protagonist: Mapped[dict] = mapped_column(JSON, nullable=False)
    recurring_characters: Mapped[list] = mapped_column(JSON, default=list)
    world_settings: Mapped[dict] = mapped_column(JSON, default=dict)
    achievements: Mapped[list] = mapped_column(JSON, default=list)

    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()
    )

    child_profile: Mapped["ChildProfile"] = relationship(
        "ChildProfile", back_populates="story_universes"
    )


class ReadingEvent(Base):
    """Reading event entity."""

    __tablename__ = "reading_events"

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    child_profile_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("child_profiles.id", ondelete="CASCADE"), nullable=False, index=True
    )
    story_id: Mapped[int | None] = mapped_column(
        Integer, ForeignKey("stories.id", ondelete="SET NULL"), nullable=True, index=True
    )
    event_type: Mapped[str] = mapped_column(String(20), nullable=False)
    reading_time: Mapped[int] = mapped_column(Integer, default=0)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), index=True
    )


class PushConfig(Base):
    """Push configuration entity."""

    __tablename__ = "push_configs"
    __table_args__ = (
        UniqueConstraint("child_profile_id", name="uq_push_config_child"),
    )

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    user_id: Mapped[str] = mapped_column(
        String(255), ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
    )
    child_profile_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("child_profiles.id", ondelete="CASCADE"), nullable=False, index=True
    )
    push_time: Mapped[time | None] = mapped_column(Time)
    push_days: Mapped[list[int]] = mapped_column(JSON, default=list)
    enabled: Mapped[bool] = mapped_column(Boolean, default=True)
    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()
    )


class PushEvent(Base):
    """Push event entity."""

    __tablename__ = "push_events"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    user_id: Mapped[str] = mapped_column(
        String(255), ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
    )
    child_profile_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("child_profiles.id", ondelete="CASCADE"), nullable=False, index=True
    )
    trigger_type: Mapped[str] = mapped_column(String(20), nullable=False)
    status: Mapped[str] = mapped_column(String(20), nullable=False)
    reason: Mapped[str | None] = mapped_column(Text)
    sent_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, index=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now()
    )


class MemoryItem(Base):
    """Memory item entity with time decay metadata."""

    __tablename__ = "memory_items"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    child_profile_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("child_profiles.id", ondelete="CASCADE"), nullable=False, index=True
    )
    universe_id: Mapped[str | None] = mapped_column(
        String(36), ForeignKey("story_universes.id", ondelete="SET NULL"), nullable=True, index=True
    )
    type: Mapped[str] = mapped_column(String(50), nullable=False)
    value: Mapped[dict] = mapped_column(JSON, nullable=False)
    base_weight: Mapped[float] = mapped_column(Float, default=1.0)
    last_used_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now()
    )
    ttl_days: Mapped[int | None] = mapped_column(Integer)