"""Task model for the Tasks plugin."""

from __future__ import annotations

import uuid
from datetime import datetime
from typing import Any

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

from app.core.db import Base, TenantMixin
from app.models.owned_mixin import OwnedMixin


class Task(Base, TenantMixin, OwnedMixin):
    """Task entity — free activities (calls, notes, visits) linked to entities.

    Supports polymorphic assignment (user/agent/group), polymorphic entity
    links (contact/company/...), subtasks, dependencies, goals/milestones and
    agent subtasks. Legacy ``contact_id`` and ``assigned_to`` columns are kept
    for backward compatibility and mirrored into the polymorphic fields.
    """

    __tablename__ = "tasks"
    __table_args__ = (
        Index("ix_tasks_tenant_deleted", "tenant_id", "deleted_at"),
        Index("ix_tasks_tenant_status", "tenant_id", "status"),
        Index("ix_tasks_tenant_assigned", "tenant_id", "assigned_to"),
        Index("ix_tasks_tenant_due", "tenant_id", "due_date"),
        Index("ix_tasks_contact", "contact_id"),
        Index("ix_tasks_tenant_entity", "tenant_id", "entity_type", "entity_id"),
        Index("ix_tasks_tenant_assignee", "tenant_id", "assignee_type", "assignee_id"),
        Index("ix_tasks_tenant_parent", "tenant_id", "parent_task_id"),
        Index("ix_tasks_tenant_type", "tenant_id", "task_type"),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        PGUUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    title: Mapped[str] = mapped_column(String(255), nullable=False)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    status: Mapped[str] = mapped_column(
        String(20), nullable=False, default="open"
    )  # open, in_progress, review, blocked, done, cancelled
    priority: Mapped[str] = mapped_column(
        String(10), nullable=False, default="medium"
    )  # low, medium, high, urgent
    due_date: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True), nullable=True
    )
    assigned_to: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("users.id", ondelete="SET NULL"), nullable=True
    )
    contact_id: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("contacts.id", ondelete="SET NULL"), nullable=True
    )
    created_by: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True), ForeignKey("users.id", ondelete="SET NULL"), nullable=True
    )
    deleted_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)

    # ── F.14 Unified Task System ────────────────────────────────────────────
    # Polymorphic assignee (user/agent/group)
    assignee_type: Mapped[str] = mapped_column(
        String(20), nullable=False, default="user"
    )  # user, agent, group
    assignee_id: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True), nullable=True
    )

    # Polymorphic entity link (contact/company/...)
    entity_type: Mapped[str | None] = mapped_column(String(80), nullable=True)
    entity_id: Mapped[uuid.UUID | None] = mapped_column(PGUUID(as_uuid=True), nullable=True)

    # Polymorphic creator (user/agent/workflow/system)
    creator_type: Mapped[str] = mapped_column(
        String(20), nullable=False, default="user"
    )  # user, agent, workflow, system
    creator_id: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True), nullable=True
    )

    # Subtasks (self-reference)
    parent_task_id: Mapped[uuid.UUID | None] = mapped_column(
        PGUUID(as_uuid=True),
        ForeignKey("tasks.id", ondelete="CASCADE"),
        nullable=True,
    )

    # Task dependencies (blocked-by task IDs)
    depends_on: Mapped[list[Any]] = mapped_column(JSONB, nullable=False, default=list)

    # Task type
    task_type: Mapped[str] = mapped_column(
        String(30), nullable=False, default="todo"
    )  # todo, approval, follow_up, review, goal, milestone, agent_subtask

    # Goal / Milestone support
    success_criteria: Mapped[dict[str, Any] | None] = mapped_column(JSONB, nullable=True)
    target_date: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True), nullable=True
    )
    progress: Mapped[int] = mapped_column(Integer, nullable=False, default=0)  # 0-100