"""add pmflow ai threads and messages

Revision ID: 20260513_add_pmflow_ai_threads
Revises: 20260513_merge_pmflow_agent_runtime_heads
Create Date: 2026-05-13
"""

from __future__ import annotations

from alembic import op
import sqlalchemy as sa


revision = "20260513_add_pmflow_ai_threads"
down_revision = "20260513_merge_pmflow_agent_runtime_heads"
branch_labels = None
depends_on = None


def _json_type():
    bind = op.get_bind()
    if bind.dialect.name == "postgresql":
        from sqlalchemy.dialects import postgresql

        return postgresql.JSONB()
    return sa.JSON()


def _table_exists(table_name: str) -> bool:
    return sa.inspect(op.get_bind()).has_table(table_name)


def _column_exists(table_name: str, column_name: str) -> bool:
    if not _table_exists(table_name):
        return False
    inspector = sa.inspect(op.get_bind())
    return any(item.get("name") == column_name for item in inspector.get_columns(table_name))


def _index_exists(table_name: str, index_name: str) -> bool:
    if not _table_exists(table_name):
        return False
    inspector = sa.inspect(op.get_bind())
    return any(item.get("name") == index_name for item in inspector.get_indexes(table_name))


def _create_index_once(index_name: str, table_name: str, columns: list[str]) -> None:
    if _table_exists(table_name) and not _index_exists(table_name, index_name):
        op.create_index(index_name, table_name, columns)


def _base_columns() -> list[sa.Column]:
    return [
        sa.Column("tenant_id", sa.BigInteger(), nullable=False, server_default="1"),
        sa.Column("created_at", sa.TIMESTAMP(), nullable=False, server_default=sa.text("now()")),
        sa.Column("updated_at", sa.TIMESTAMP(), nullable=False, server_default=sa.text("now()")),
    ]


def upgrade() -> None:
    json_type = _json_type()

    if not _table_exists("pmflow_ai_threads"):
        op.create_table(
            "pmflow_ai_threads",
            sa.Column("id", sa.Integer(), primary_key=True, autoincrement=True),
            sa.Column("public_thread_id", sa.String(length=80), nullable=False),
            sa.Column("user_id", sa.BigInteger(), sa.ForeignKey("users.id"), nullable=True),
            sa.Column("qa_session_id", sa.BigInteger(), sa.ForeignKey("qa_sessions.id", ondelete="SET NULL"), nullable=True),
            sa.Column("workspace_scope", sa.String(length=80), nullable=True),
            sa.Column("surface", sa.String(length=80), nullable=True),
            sa.Column("title", sa.String(length=240), nullable=False, server_default="PMFlow AI"),
            sa.Column("status", sa.String(length=32), nullable=False, server_default="active"),
            sa.Column("current_object_refs", json_type, nullable=True),
            sa.Column("last_run_public_id", sa.String(length=80), nullable=True),
            sa.Column("last_message_preview", sa.Text(), nullable=True),
            sa.Column("message_count", sa.Integer(), nullable=False, server_default="0"),
            sa.Column("thread_metadata", json_type, nullable=True),
            sa.Column("started_at", sa.TIMESTAMP(), nullable=True),
            sa.Column("last_message_at", sa.TIMESTAMP(), nullable=True),
            *_base_columns(),
            sa.UniqueConstraint("tenant_id", "public_thread_id", name="uq_pmflow_ai_threads_tenant_public_thread_id"),
        )
    _create_index_once("ix_pmflow_ai_threads_tenant_id", "pmflow_ai_threads", ["tenant_id"])
    _create_index_once("ix_pmflow_ai_threads_public_thread_id", "pmflow_ai_threads", ["public_thread_id"])
    _create_index_once("ix_pmflow_ai_threads_user_id", "pmflow_ai_threads", ["user_id"])
    _create_index_once("ix_pmflow_ai_threads_qa_session_id", "pmflow_ai_threads", ["qa_session_id"])
    _create_index_once("ix_pmflow_ai_threads_workspace_scope", "pmflow_ai_threads", ["workspace_scope"])
    _create_index_once("ix_pmflow_ai_threads_status", "pmflow_ai_threads", ["status"])
    _create_index_once("ix_pmflow_ai_threads_last_run_public_id", "pmflow_ai_threads", ["last_run_public_id"])
    _create_index_once("ix_pmflow_ai_threads_started_at", "pmflow_ai_threads", ["started_at"])
    _create_index_once("ix_pmflow_ai_threads_last_message_at", "pmflow_ai_threads", ["last_message_at"])

    if _table_exists("pmflow_agent_runs") and not _column_exists("pmflow_agent_runs", "thread_id"):
        op.add_column("pmflow_agent_runs", sa.Column("thread_id", sa.BigInteger(), nullable=True))
        op.create_foreign_key(
            "fk_pmflow_agent_runs_thread_id_pmflow_ai_threads",
            "pmflow_agent_runs",
            "pmflow_ai_threads",
            ["thread_id"],
            ["id"],
            ondelete="SET NULL",
        )
    _create_index_once("ix_pmflow_agent_runs_thread_id", "pmflow_agent_runs", ["thread_id"])

    if not _table_exists("pmflow_ai_messages"):
        op.create_table(
            "pmflow_ai_messages",
            sa.Column("id", sa.Integer(), primary_key=True, autoincrement=True),
            sa.Column("thread_id", sa.BigInteger(), sa.ForeignKey("pmflow_ai_threads.id", ondelete="CASCADE"), nullable=False),
            sa.Column("public_message_id", sa.String(length=80), nullable=False),
            sa.Column("role", sa.String(length=24), nullable=False),
            sa.Column("message_index", sa.Integer(), nullable=False, server_default="0"),
            sa.Column("run_public_id", sa.String(length=80), nullable=True),
            sa.Column("qa_record_id", sa.BigInteger(), sa.ForeignKey("qa_records.id", ondelete="SET NULL"), nullable=True),
            sa.Column("content", sa.Text(), nullable=False, server_default=""),
            sa.Column("message_payload", json_type, nullable=True),
            sa.Column("sent_at", sa.TIMESTAMP(), nullable=True),
            *_base_columns(),
            sa.UniqueConstraint("tenant_id", "thread_id", "public_message_id", name="uq_pmflow_ai_messages_tenant_thread_public_message"),
        )
    _create_index_once("ix_pmflow_ai_messages_tenant_id", "pmflow_ai_messages", ["tenant_id"])
    _create_index_once("ix_pmflow_ai_messages_thread_id", "pmflow_ai_messages", ["thread_id"])
    _create_index_once("ix_pmflow_ai_messages_public_message_id", "pmflow_ai_messages", ["public_message_id"])
    _create_index_once("ix_pmflow_ai_messages_role", "pmflow_ai_messages", ["role"])
    _create_index_once("ix_pmflow_ai_messages_message_index", "pmflow_ai_messages", ["message_index"])
    _create_index_once("ix_pmflow_ai_messages_run_public_id", "pmflow_ai_messages", ["run_public_id"])
    _create_index_once("ix_pmflow_ai_messages_qa_record_id", "pmflow_ai_messages", ["qa_record_id"])
    _create_index_once("ix_pmflow_ai_messages_sent_at", "pmflow_ai_messages", ["sent_at"])


def downgrade() -> None:
    if _table_exists("pmflow_ai_messages"):
        op.drop_table("pmflow_ai_messages")
    if _table_exists("pmflow_agent_runs") and _column_exists("pmflow_agent_runs", "thread_id"):
        op.drop_column("pmflow_agent_runs", "thread_id")
    if _table_exists("pmflow_ai_threads"):
        op.drop_table("pmflow_ai_threads")