"""Workflow, WorkflowInstance, and WorkflowStepHistory models — tenant-scoped with RLS."""

from __future__ import annotations

import uuid
from datetime import datetime
from typing import Any

from sqlalchemy import String, Text, DateTime, ForeignKey, func, Index, Integer, Boolean
from sqlalchemy.dialects.postgresql import UUID as PGUUID, JSONB
from sqlalchemy.orm import Mapped, mapped_column

from app.core.db import Base, TenantMixin


class Workflow(Base, TenantMixin):
    """Workflow definition — a template of steps stored as JSONB, tenant-scoped."""

    __tablename__ = "workflows"
    __table_args__ = (
        Index("ix_workflows_tenant_active", "tenant_id", "is_active"),
        Index("ix_workflows_tenant_trigger", "tenant_id", "trigger_event"),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    name: Mapped[str] = mapped_column(String(200), nullable=False)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    trigger_event: Mapped[str | None] = mapped_column(String(100), nullable=True)
    steps: Mapped[list[dict[str, Any]]] = mapped_column(JSONB, nullable=False)
    is_active: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True)
    created_by: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("users.id", ondelete="SET NULL"), nullable=True
    )


class WorkflowInstance(Base, TenantMixin):
    """A running instance of a workflow — tracks current step, status, context."""

    __tablename__ = "workflow_instances"
    __table_args__ = (
        Index("ix_wf_instances_tenant_status", "tenant_id", "status"),
        Index("ix_wf_instances_tenant_workflow", "tenant_id", "workflow_id"),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    workflow_id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("workflows.id", ondelete="CASCADE"), nullable=False, index=True
    )
    status: Mapped[str] = mapped_column(String(30), nullable=False, default="pending")
    # pending → in_progress → completed / rejected / cancelled
    current_step_index: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    context: Mapped[dict[str, Any]] = mapped_column(JSONB, default=dict, nullable=False)
    initiated_by: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("users.id", ondelete="SET NULL"), nullable=True
    )
    completed_at: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True), nullable=True
    )
    timeout_hours: Mapped[int | None] = mapped_column(Integer, nullable=True)
    timeout_at: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True), nullable=True
    )


class WorkflowStepHistory(Base, TenantMixin):
    """Immutable record of every step transition in a workflow instance."""

    __tablename__ = "workflow_step_history"
    __table_args__ = (
        Index("ix_wf_step_history_tenant_instance", "tenant_id", "instance_id"),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    instance_id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("workflow_instances.id", ondelete="CASCADE"), nullable=False, index=True
    )
    step_index: Mapped[int] = mapped_column(Integer, nullable=False)
    step_type: Mapped[str] = mapped_column(String(50), nullable=False)
    action: Mapped[str] = mapped_column(String(50), nullable=False)  # entered, approved, rejected, skipped, cancelled
    actor_id: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("users.id", ondelete="SET NULL"), nullable=True
    )
    details: Mapped[dict[str, Any] | None] = mapped_column(JSONB, nullable=True)