"""Convert ZeroTier table timestamp columns from TIMESTAMPTZ to TIMESTAMP.

Revision ID: 025_fix_zt_timestamps
Revises: 024_fix_zerotier_schema
Create Date: 2026-03-22

Migration 020_zerotier (and 023's fallback create_table) defined ZeroTier tables
with sa.DateTime(timezone=True), producing TIMESTAMP WITH TIME ZONE columns.
The rest of the codebase uses plain DateTime (timezone-naive TIMESTAMP WITHOUT
TIME ZONE).  This migration aligns all ZeroTier table timestamp columns with the
existing codebase convention.

GUARDED: Each ALTER is only executed if the column is currently
TIMESTAMP WITH TIME ZONE.  On a DB that has already been converted (e.g. dev),
the migration is a harmless no-op.
"""

from alembic import op
import sqlalchemy as sa

revision = "025_fix_zt_timestamps"
down_revision = "024_fix_zerotier_schema"
branch_labels = None
depends_on = None

# All ZeroTier tables that inherit BaseModel's created_at/updated_at/deleted_at
_ZT_BASE_TABLES = [
    "portal_networks",
    "devices",
    "device_network_memberships",
    "user_network_approvals",
    "kill_switch_events",
    "activation_sessions",
    "zerotier_memberships",
]

# Additional datetime columns specific to individual models
_EXTRA_COLS = {
    "activation_sessions": ["authenticated_at", "expires_at", "ended_at"],
    "zerotier_memberships": ["join_seen_at", "last_synced_at"],
}


def _col_is_timestamptz(conn, table: str, column: str) -> bool:
    """Return True if the column is TIMESTAMP WITH TIME ZONE."""
    row = conn.execute(sa.text(
        "SELECT data_type FROM information_schema.columns "
        "WHERE table_name = :t AND column_name = :c"
    ), {"t": table, "c": column}).first()
    return row is not None and row[0] == "timestamp with time zone"


def _col_is_timestamp(conn, table: str, column: str) -> bool:
    """Return True if the column is TIMESTAMP WITHOUT TIME ZONE."""
    row = conn.execute(sa.text(
        "SELECT data_type FROM information_schema.columns "
        "WHERE table_name = :t AND column_name = :c"
    ), {"t": table, "c": column}).first()
    return row is not None and row[0] == "timestamp without time zone"


def upgrade():
    conn = op.get_bind()

    for tbl in _ZT_BASE_TABLES:
        for col in ("created_at", "updated_at", "deleted_at"):
            if _col_is_timestamptz(conn, tbl, col):
                conn.execute(sa.text(
                    f'ALTER TABLE "{tbl}" ALTER COLUMN "{col}" '
                    f'TYPE TIMESTAMP WITHOUT TIME ZONE '
                    f'USING "{col}" AT TIME ZONE \'UTC\''
                ))
        for col in _EXTRA_COLS.get(tbl, []):
            if _col_is_timestamptz(conn, tbl, col):
                conn.execute(sa.text(
                    f'ALTER TABLE "{tbl}" ALTER COLUMN "{col}" '
                    f'TYPE TIMESTAMP WITHOUT TIME ZONE '
                    f'USING CASE WHEN "{col}" IS NULL THEN NULL '
                    f'ELSE "{col}" AT TIME ZONE \'UTC\' END'
                ))


def downgrade():
    conn = op.get_bind()

    for tbl in _ZT_BASE_TABLES:
        for col in ("created_at", "updated_at", "deleted_at"):
            if _col_is_timestamp(conn, tbl, col):
                conn.execute(sa.text(
                    f'ALTER TABLE "{tbl}" ALTER COLUMN "{col}" '
                    f'TYPE TIMESTAMP WITH TIME ZONE '
                    f'USING "{col}" AT TIME ZONE \'UTC\''
                ))
        for col in _EXTRA_COLS.get(tbl, []):
            if _col_is_timestamp(conn, tbl, col):
                conn.execute(sa.text(
                    f'ALTER TABLE "{tbl}" ALTER COLUMN "{col}" '
                    f'TYPE TIMESTAMP WITH TIME ZONE '
                    f'USING CASE WHEN "{col}" IS NULL THEN NULL '
                    f'ELSE "{col}" AT TIME ZONE \'UTC\' END'
                ))