"""階段 2a: projects + tasks

新增兩張表:
  - projects ─ 專案(任務的容器,可選)
  - tasks    ─ 任務本身

Revision ID: 0002_projects_and_tasks
Revises: 0001_initial_users
Create Date: 2026-05-05
"""

from typing import Sequence, Union

import sqlalchemy as sa
from alembic import op
from sqlalchemy.dialects import postgresql


# revision identifiers, used by Alembic.
revision: str = "0002_projects_and_tasks"
down_revision: Union[str, None] = "0001_initial_users"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    # ---------- projects ----------
    op.create_table(
        "projects",
        sa.Column("id", postgresql.UUID(as_uuid=True), primary_key=True, nullable=False),
        sa.Column("name", sa.String(length=200), nullable=False),
        sa.Column("description", sa.Text(), nullable=True),
        sa.Column("color", sa.String(length=7), nullable=False, server_default="#1F4E79"),
        sa.Column(
            "owner_id",
            postgresql.UUID(as_uuid=True),
            sa.ForeignKey("users.id", ondelete="RESTRICT"),
            nullable=False,
        ),
        sa.Column("status", sa.String(length=20), nullable=False, server_default="active"),
        sa.Column(
            "created_at",
            sa.DateTime(timezone=True),
            server_default=sa.text("now()"),
            nullable=False,
        ),
        sa.Column(
            "updated_at",
            sa.DateTime(timezone=True),
            server_default=sa.text("now()"),
            nullable=False,
        ),
        sa.Column("deleted_at", sa.DateTime(timezone=True), nullable=True),
    )
    op.create_index("ix_projects_owner_id", "projects", ["owner_id"], unique=False)
    op.create_index("ix_projects_deleted_at", "projects", ["deleted_at"], unique=False)

    # ---------- tasks ----------
    op.create_table(
        "tasks",
        sa.Column("id", postgresql.UUID(as_uuid=True), primary_key=True, nullable=False),
        sa.Column(
            "project_id",
            postgresql.UUID(as_uuid=True),
            sa.ForeignKey("projects.id", ondelete="SET NULL"),
            nullable=True,
        ),
        sa.Column("title", sa.String(length=500), nullable=False),
        sa.Column("description", sa.Text(), nullable=True),
        sa.Column("status", sa.String(length=20), nullable=False, server_default="todo"),
        sa.Column("priority", sa.String(length=10), nullable=False, server_default="medium"),
        sa.Column("due_date", sa.Date(), nullable=True),
        sa.Column(
            "created_by",
            postgresql.UUID(as_uuid=True),
            sa.ForeignKey("users.id", ondelete="RESTRICT"),
            nullable=False,
        ),
        sa.Column(
            "assignee_id",
            postgresql.UUID(as_uuid=True),
            sa.ForeignKey("users.id", ondelete="SET NULL"),
            nullable=True,
        ),
        sa.Column("order_index", sa.Integer(), nullable=False, server_default="0"),
        sa.Column("completed_at", sa.DateTime(timezone=True), nullable=True),
        sa.Column(
            "created_at",
            sa.DateTime(timezone=True),
            server_default=sa.text("now()"),
            nullable=False,
        ),
        sa.Column(
            "updated_at",
            sa.DateTime(timezone=True),
            server_default=sa.text("now()"),
            nullable=False,
        ),
        sa.Column("deleted_at", sa.DateTime(timezone=True), nullable=True),
    )
    op.create_index("ix_tasks_project_id", "tasks", ["project_id"], unique=False)
    op.create_index("ix_tasks_status", "tasks", ["status"], unique=False)
    op.create_index("ix_tasks_due_date", "tasks", ["due_date"], unique=False)
    op.create_index("ix_tasks_created_by", "tasks", ["created_by"], unique=False)
    op.create_index("ix_tasks_assignee_id", "tasks", ["assignee_id"], unique=False)
    op.create_index("ix_tasks_deleted_at", "tasks", ["deleted_at"], unique=False)


def downgrade() -> None:
    op.drop_index("ix_tasks_deleted_at", table_name="tasks")
    op.drop_index("ix_tasks_assignee_id", table_name="tasks")
    op.drop_index("ix_tasks_created_by", table_name="tasks")
    op.drop_index("ix_tasks_due_date", table_name="tasks")
    op.drop_index("ix_tasks_status", table_name="tasks")
    op.drop_index("ix_tasks_project_id", table_name="tasks")
    op.drop_table("tasks")

    op.drop_index("ix_projects_deleted_at", table_name="projects")
    op.drop_index("ix_projects_owner_id", table_name="projects")
    op.drop_table("projects")