"""AI Chat Builder session tracking.

Stores conversational flow builder state across the multi-phase interview.
Sessions expire after 24 hours.
"""
import uuid
from datetime import datetime, timezone
from typing import Optional, Any

from sqlalchemy import String, DateTime, ForeignKey, Integer
from sqlalchemy.orm import Mapped, mapped_column
from sqlalchemy.dialects.postgresql import UUID, JSONB

from app.core.database import Base


class AIChatSession(Base):
    __tablename__ = "ai_chat_sessions"

    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"),
        nullable=False,
        index=True,
    )
    account_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("accounts.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    status: Mapped[str] = mapped_column(
        String(20),
        nullable=False,
        default="active",
        comment="active | completed | abandoned",
    )
    current_phase: Mapped[str] = mapped_column(
        String(20),
        nullable=False,
        default="scoping",
        comment="scoping | discovery | enrichment | review | generation",
    )
    flow_type: Mapped[str] = mapped_column(
        String(20),
        nullable=False,
        comment="troubleshooting | procedural",
    )
    conversation_history: Mapped[list[dict[str, Any]]] = mapped_column(
        JSONB, nullable=False, default=list
    )
    working_tree: Mapped[Optional[dict[str, Any]]] = mapped_column(
        JSONB, nullable=True
    )
    tree_metadata: Mapped[dict[str, Any]] = mapped_column(
        JSONB, nullable=False, default=dict
    )
    provider_used: Mapped[Optional[str]] = mapped_column(
        String(20), nullable=True
    )
    message_count: Mapped[int] = mapped_column(
        Integer, nullable=False, default=0
    )
    total_input_tokens: Mapped[int] = mapped_column(
        Integer, nullable=False, default=0
    )
    total_output_tokens: Mapped[int] = mapped_column(
        Integer, nullable=False, default=0
    )
    generated_tree_id: Mapped[Optional[uuid.UUID]] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("trees.id", ondelete="SET NULL"),
        nullable=True,
    )
    expires_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc),
        onupdate=lambda: datetime.now(timezone.utc),
    )
    # Editor-embedded session: links to a specific tree/flow
    tree_id: Mapped[Optional[uuid.UUID]] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("trees.id", ondelete="CASCADE"),
        nullable=True,
        index=True,
    )
    archived_at: Mapped[Optional[datetime]] = mapped_column(
        DateTime(timezone=True),
        nullable=True,
    )