"""initial schema: channels + messages

Revision ID: 0001
Revises:
Create Date: 2026-05-05

"""
from typing import Sequence, Union

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

revision: str = "0001"
down_revision: Union[str, None] = None
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.create_table(
        "channels",
        sa.Column("id", sa.Integer(), primary_key=True),
        sa.Column("tg_id", sa.BigInteger(), nullable=True, unique=True),
        sa.Column("identifier", sa.String(length=255), nullable=False, unique=True),
        sa.Column("title", sa.String(length=512), nullable=True),
        sa.Column("is_active", sa.Boolean(), nullable=False, server_default=sa.text("true")),
        sa.Column("last_message_id", sa.BigInteger(), nullable=True),
        sa.Column("last_polled_at", sa.DateTime(timezone=True), nullable=True),
        sa.Column(
            "created_at",
            sa.DateTime(timezone=True),
            nullable=False,
            server_default=sa.func.now(),
        ),
    )

    op.create_table(
        "messages",
        sa.Column("id", sa.Integer(), primary_key=True),
        sa.Column(
            "channel_id",
            sa.Integer(),
            sa.ForeignKey("channels.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column("tg_message_id", sa.BigInteger(), nullable=False),
        sa.Column("date", sa.DateTime(timezone=True), nullable=False),
        sa.Column("text", sa.Text(), nullable=True),
        sa.Column("sender_id", sa.BigInteger(), nullable=True),
        sa.Column("has_media", sa.Boolean(), nullable=False, server_default=sa.text("false")),
        sa.Column("views", sa.Integer(), nullable=True),
        sa.Column("forwards", sa.Integer(), nullable=True),
        sa.Column("raw", postgresql.JSONB(), nullable=True),
        sa.Column(
            "fetched_at",
            sa.DateTime(timezone=True),
            nullable=False,
            server_default=sa.func.now(),
        ),
        sa.UniqueConstraint("channel_id", "tg_message_id", name="uq_channel_message"),
    )
    op.create_index(
        "ix_messages_channel_date", "messages", ["channel_id", "date"], unique=False
    )


def downgrade() -> None:
    op.drop_index("ix_messages_channel_date", table_name="messages")
    op.drop_table("messages")
    op.drop_table("channels")