"""SQLAlchemy ORM models for NEXUS."""

from __future__ import annotations

import uuid
from datetime import datetime
from typing import Optional

from sqlalchemy import (
    JSON,
    DateTime,
    Float,
    ForeignKey,
    Integer,
    String,
    Text,
    UniqueConstraint,
    func,
)
from sqlalchemy.dialects.postgresql import JSONB, UUID
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship


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


class Base(DeclarativeBase):
    pass


class User(Base):
    __tablename__ = "users"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    email: Mapped[str] = mapped_column(String(255), unique=True, index=True, nullable=False)
    name: Mapped[Optional[str]] = mapped_column(String(255))
    google_id: Mapped[Optional[str]] = mapped_column(String(255), unique=True, index=True)
    api_key_hash: Mapped[Optional[str]] = mapped_column(String(255))
    plan: Mapped[str] = mapped_column(String(32), default="free", nullable=False)
    credits_used: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )

    tasks: Mapped[list["Task"]] = relationship(back_populates="user")


class Task(Base):
    __tablename__ = "tasks"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    user_id: Mapped[Optional[str]] = mapped_column(
        String(36), ForeignKey("users.id", ondelete="SET NULL"), index=True
    )
    topic: Mapped[str] = mapped_column(Text, nullable=False)
    slide_count: Mapped[int] = mapped_column(Integer, default=8, nullable=False)
    theme: Mapped[str] = mapped_column(String(64), default="Editorial", nullable=False)
    search_web: Mapped[bool] = mapped_column(default=True, nullable=False)
    status: Mapped[str] = mapped_column(String(32), default="pending", index=True, nullable=False)
    progress_pct: Mapped[float] = mapped_column(Float, default=0.0, nullable=False)
    current_step: Mapped[str] = mapped_column(String(255), default="", nullable=False)
    error_msg: Mapped[Optional[str]] = mapped_column(Text)
    tokens_used: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
    cost_usd: Mapped[float] = mapped_column(Float, default=0.0, nullable=False)
    model_used: Mapped[Optional[str]] = mapped_column(String(64))
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )
    completed_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True))

    user: Mapped[Optional[User]] = relationship(back_populates="tasks")
    slides: Mapped[Optional["SlideDeck"]] = relationship(
        back_populates="task", uselist=False, cascade="all, delete-orphan"
    )
    exports: Mapped[list["Export"]] = relationship(
        back_populates="task", cascade="all, delete-orphan"
    )
    share_tokens: Mapped[list["ShareToken"]] = relationship(
        back_populates="task", cascade="all, delete-orphan"
    )


class SlideDeck(Base):
    __tablename__ = "slides"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    task_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("tasks.id", ondelete="CASCADE"), unique=True, index=True
    )
    slide_data: Mapped[list] = mapped_column(JSON().with_variant(JSONB, "postgresql"), nullable=False)
    theme: Mapped[str] = mapped_column(String(64), default="Editorial", nullable=False)
    slide_count: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )

    task: Mapped[Task] = relationship(back_populates="slides")


class Export(Base):
    __tablename__ = "exports"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    task_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("tasks.id", ondelete="CASCADE"), index=True
    )
    format: Mapped[str] = mapped_column(String(16), nullable=False)
    file_url: Mapped[str] = mapped_column(Text, nullable=False)
    file_size: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )

    task: Mapped[Task] = relationship(back_populates="exports")


class ShareToken(Base):
    __tablename__ = "share_tokens"
    __table_args__ = (UniqueConstraint("token", name="uq_share_token"),)

    token: Mapped[str] = mapped_column(String(64), primary_key=True)
    task_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("tasks.id", ondelete="CASCADE"), index=True
    )
    views: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
    expires_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True))
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )

    task: Mapped[Task] = relationship(back_populates="share_tokens")


# ── Agent runtime (Phase 1 foundation) ─────────────────────────────────────
# These tables back the dynamic tool-calling loop introduced in Phase 2.
# They are additive: existing slide-generation flow does not use them yet.
# Tables are created automatically by ``init_models`` (dev/SQLite) and via
# Alembic in production.

class AgentRun(Base):
    __tablename__ = "agent_runs"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    task_id: Mapped[Optional[str]] = mapped_column(
        String(36), ForeignKey("tasks.id", ondelete="CASCADE"), index=True
    )
    user_id: Mapped[Optional[str]] = mapped_column(
        String(36), ForeignKey("users.id", ondelete="SET NULL"), index=True
    )
    goal: Mapped[str] = mapped_column(Text, nullable=False)
    status: Mapped[str] = mapped_column(
        String(32), default="pending", index=True, nullable=False
    )
    max_steps: Mapped[int] = mapped_column(Integer, default=20, nullable=False)
    step_count: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
    error_msg: Mapped[Optional[str]] = mapped_column(Text)
    meta: Mapped[dict] = mapped_column(
        JSON().with_variant(JSONB, "postgresql"), default=dict, nullable=False
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )
    completed_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True))

    steps: Mapped[list["AgentStep"]] = relationship(
        back_populates="run", cascade="all, delete-orphan", order_by="AgentStep.step_index"
    )
    artifacts: Mapped[list["Artifact"]] = relationship(
        back_populates="run", cascade="all, delete-orphan"
    )


class AgentStep(Base):
    __tablename__ = "agent_steps"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    run_id: Mapped[str] = mapped_column(
        String(36), ForeignKey("agent_runs.id", ondelete="CASCADE"), index=True, nullable=False
    )
    step_index: Mapped[int] = mapped_column(Integer, nullable=False)
    kind: Mapped[str] = mapped_column(String(32), nullable=False)  # "thought" | "action" | "observation" | "final"
    action: Mapped[Optional[str]] = mapped_column(String(64))     # tool name when kind=="action"
    status: Mapped[str] = mapped_column(String(32), default="ok", nullable=False)
    input_json: Mapped[dict] = mapped_column(
        JSON().with_variant(JSONB, "postgresql"), default=dict, nullable=False
    )
    output_json: Mapped[dict] = mapped_column(
        JSON().with_variant(JSONB, "postgresql"), default=dict, nullable=False
    )
    error: Mapped[Optional[str]] = mapped_column(Text)
    started_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )
    completed_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True))

    run: Mapped[AgentRun] = relationship(back_populates="steps")


class Artifact(Base):
    __tablename__ = "artifacts"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
    run_id: Mapped[Optional[str]] = mapped_column(
        String(36), ForeignKey("agent_runs.id", ondelete="CASCADE"), index=True
    )
    task_id: Mapped[Optional[str]] = mapped_column(
        String(36), ForeignKey("tasks.id", ondelete="CASCADE"), index=True
    )
    artifact_type: Mapped[str] = mapped_column(String(64), index=True, nullable=False)
    title: Mapped[Optional[str]] = mapped_column(String(255))
    meta: Mapped[dict] = mapped_column(
        JSON().with_variant(JSONB, "postgresql"), default=dict, nullable=False
    )
    file_url: Mapped[Optional[str]] = mapped_column(Text)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )

    run: Mapped[Optional[AgentRun]] = relationship(back_populates="artifacts")