"""Complete V3 read-only operations foundation.

Revision ID: 202607090001
Revises: 202607080002
Create Date: 2026-07-09
"""

from alembic import op
import sqlalchemy as sa
from sqlalchemy import inspect


revision = "202607090001"
down_revision = "202607080002"
branch_labels = None
depends_on = None

DOMAIN_EVENTS_TABLE = "domain_events"
AI_MEMORY_ENTRIES_TABLE = "ai_memory_entries"
SYSTEM_HEARTBEATS_TABLE = "system_heartbeats"


def _table_exists(table_name: str) -> bool:
    inspector = inspect(op.get_bind())
    return table_name in inspector.get_table_names()


def _column_names(table_name: str) -> set[str]:
    inspector = inspect(op.get_bind())
    if table_name not in inspector.get_table_names():
        return set()
    return {column["name"] for column in inspector.get_columns(table_name)}


def _add_column_if_missing(table_name: str, column: sa.Column) -> None:
    if column.name not in _column_names(table_name):
        op.add_column(table_name, column)


def _create_indexes(table_name: str, indexes: list[tuple[str, bool]]) -> None:
    for column_name, unique in indexes:
        op.create_index(
            op.f(f"ix_{table_name}_{column_name}"),
            table_name,
            [column_name],
            unique=unique,
            if_not_exists=True,
        )


def upgrade() -> None:
    for column in [
        sa.Column("next_attempt_at", sa.DateTime(), nullable=True),
        sa.Column("locked_until", sa.DateTime(), nullable=True),
        sa.Column("locked_by", sa.String(length=128), nullable=True),
        sa.Column("max_attempts", sa.Integer(), nullable=True),
    ]:
        _add_column_if_missing(DOMAIN_EVENTS_TABLE, column)
    _create_indexes(
        DOMAIN_EVENTS_TABLE,
        [
            ("next_attempt_at", False),
            ("locked_until", False),
            ("locked_by", False),
        ],
    )

    if not _table_exists(AI_MEMORY_ENTRIES_TABLE):
        op.create_table(
            AI_MEMORY_ENTRIES_TABLE,
            sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
            sa.Column("code", sa.String(length=64), nullable=False),
            sa.Column("scope", sa.String(length=64), nullable=False),
            sa.Column("subject", sa.String(length=128), nullable=False),
            sa.Column("content", sa.Text(), nullable=False),
            sa.Column("summary", sa.Text(), nullable=True),
            sa.Column("tags", sa.JSON(), nullable=True),
            sa.Column("source", sa.String(length=64), nullable=False),
            sa.Column("importance", sa.Integer(), nullable=False),
            sa.Column("status", sa.String(length=32), nullable=False),
            sa.Column("actor", sa.String(length=128), nullable=False),
            sa.Column("last_used_at", sa.DateTime(), nullable=True),
            sa.Column("expires_at", sa.DateTime(), nullable=True),
            sa.Column("created_at", sa.DateTime(), nullable=False),
            sa.Column("updated_at", sa.DateTime(), nullable=False),
            sa.PrimaryKeyConstraint("id"),
        )
        _create_indexes(
            AI_MEMORY_ENTRIES_TABLE,
            [
                ("code", True),
                ("scope", False),
                ("subject", False),
                ("source", False),
                ("importance", False),
                ("status", False),
                ("actor", False),
                ("last_used_at", False),
                ("expires_at", False),
                ("created_at", False),
            ],
        )

    if not _table_exists(SYSTEM_HEARTBEATS_TABLE):
        op.create_table(
            SYSTEM_HEARTBEATS_TABLE,
            sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
            sa.Column("component", sa.String(length=128), nullable=False),
            sa.Column("instance_id", sa.String(length=128), nullable=False),
            sa.Column("status", sa.String(length=32), nullable=False),
            sa.Column("last_seen_at", sa.DateTime(), nullable=False),
            sa.Column("created_at", sa.DateTime(), nullable=False),
            sa.Column("updated_at", sa.DateTime(), nullable=False),
            sa.PrimaryKeyConstraint("id"),
        )
        _create_indexes(
            SYSTEM_HEARTBEATS_TABLE,
            [
                ("component", False),
                ("instance_id", False),
                ("status", False),
                ("last_seen_at", False),
                ("created_at", False),
            ],
        )


def downgrade() -> None:
    for table_name in [SYSTEM_HEARTBEATS_TABLE, AI_MEMORY_ENTRIES_TABLE]:
        if _table_exists(table_name):
            op.drop_table(table_name)

    event_columns = _column_names(DOMAIN_EVENTS_TABLE)
    for column_name in ["locked_by", "locked_until", "next_attempt_at"]:
        if column_name in event_columns:
            op.drop_index(op.f(f"ix_{DOMAIN_EVENTS_TABLE}_{column_name}"), table_name=DOMAIN_EVENTS_TABLE)
            op.drop_column(DOMAIN_EVENTS_TABLE, column_name)
    if "max_attempts" in _column_names(DOMAIN_EVENTS_TABLE):
        op.drop_column(DOMAIN_EVENTS_TABLE, "max_attempts")