"""device diagnostics reports

Adds device_diagnostics_reports — structured storage for the firmware's
diagnostics_report MQTT event (vesper/{uid}/status/info, type="diagnostics_report"),
published every 5 minutes. Cleanly separate from device_boot_events (one row per
boot, event-driven) and heartbeats (one row every 30s, transport/liveness facts):
this table is periodic health telemetry — CPU temperature (min/max/avg over the
5-minute window), WiFi reconnect count + last disconnect reason, OTA/firmware
check state, and per-task stack high-water marks (bytes free).

stack_high_water is stored as a JSON-encoded TEXT column rather than flattened
columns — unlike the other three groups (fixed field sets), the set of
monitored tasks is open-ended on the firmware side (see project-vesper's
Telemetry::registerTaskForStackMonitoring), so a fixed column per task would
need a migration every time a task is added. TEXT (not JSONB) matches this
codebase's existing convention for JSON blobs stored via raw SQL — see
commands.command_payload / response_payload.

Revision ID: a7b8c9d0e1f2
Revises: f6a7b8c9d0e1
Create Date: 2026-07-17 00:00:00.000000
"""
from typing import Sequence, Union
import sqlalchemy as sa
from alembic import op

revision: str = "a7b8c9d0e1f2"
down_revision: Union[str, None] = "f6a7b8c9d0e1"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.create_table(
        "device_diagnostics_reports",
        sa.Column("id",            sa.BigInteger(), primary_key=True, autoincrement=True),
        sa.Column("device_serial", sa.String(128), nullable=False),

        # cpu_temp — omitted by firmware (all null here) if no samples were
        # taken yet this window (e.g. very first report shortly after boot).
        sa.Column("cpu_temp_avg",     sa.Float(),   nullable=True),
        sa.Column("cpu_temp_min",     sa.Float(),   nullable=True),
        sa.Column("cpu_temp_max",     sa.Float(),   nullable=True),
        sa.Column("cpu_temp_samples", sa.Integer(), nullable=True),

        # wifi_reconnects — this-boot-only lifetime count, not device lifetime.
        sa.Column("wifi_reconnect_count",        sa.Integer(), nullable=True),
        sa.Column("wifi_last_disconnect_reason", sa.String(64), nullable=True),
        sa.Column("wifi_last_disconnect_uptime_ms", sa.BigInteger(), nullable=True),

        # ota
        sa.Column("ota_current_version",   sa.String(32),  nullable=True),
        sa.Column("ota_update_available",  sa.Boolean(),   nullable=True),
        sa.Column("ota_available_version", sa.String(32),  nullable=True),
        sa.Column("ota_last_check_uptime_ms", sa.BigInteger(), nullable=True),
        sa.Column("ota_last_error",        sa.String(32),  nullable=True),

        # stack_high_water — open-ended task set, see module docstring.
        sa.Column("stack_high_water", sa.Text(), nullable=True),

        sa.Column("received_at", sa.DateTime(timezone=True), nullable=False,
                  server_default=sa.func.now()),
    )
    op.create_index(
        "idx_device_diagnostics_reports_serial_received",
        "device_diagnostics_reports",
        ["device_serial", sa.text("received_at DESC")],
    )


def downgrade() -> None:
    op.drop_index("idx_device_diagnostics_reports_serial_received", table_name="device_diagnostics_reports")
    op.drop_table("device_diagnostics_reports")