from __future__ import annotations

from collections.abc import Sequence
from typing import Any

from django.apps import AppConfig
from django.conf import settings
from django.core.checks import Error, Warning, register


class ApiConfig(AppConfig):
    name = "hc.api"


@register()
def settings_check(
    app_configs: Sequence[AppConfig] | None,
    databases: Sequence[str] | None,
    **kwargs: dict[str, Any],
) -> list[Warning]:
    items = []

    site_root_parts = settings.SITE_ROOT.split("://")
    if site_root_parts[0] not in ("http", "https"):
        items.append(
            Warning(
                "Invalid settings.SITE_ROOT value",
                hint="SITE_ROOT should start with either http:// or https://",
                id="hc.api.W001",
            )
        )

    if not settings.EMAIL_HOST:
        items.append(
            Warning(
                "settings.EMAIL_HOST is not set, cannot send email",
                hint="See https://github.com/healthchecks/healthchecks#sending-emails",
                id="hc.api.W002",
            )
        )

    return items


@register()
def whatsapp_settings_check(
    app_configs: Sequence[AppConfig] | None,
    databases: Sequence[str] | None,
    **kwargs: dict[str, Any],
) -> list[Warning]:
    if not settings.TWILIO_USE_WHATSAPP:
        return []

    items = []
    for key in (
        "TWILIO_ACCOUNT",
        "TWILIO_AUTH",
        "TWILIO_FROM",
        "TWILIO_MESSAGING_SERVICE_SID",
        "WHATSAPP_DOWN_CONTENT_SID",
        "WHATSAPP_UP_CONTENT_SID",
    ):
        if not getattr(settings, key):
            items.append(
                Warning(
                    f"The WhatsApp integration requires the settings.{key} to be set",
                    hint=f"See https://healthchecks.io/docs/self_hosted_configuration/#{key}",
                    id="hc.api.W003",
                )
            )

    return items


@register()
def mariadb_uuid_check(
    app_configs: Sequence[AppConfig] | None,
    databases: Sequence[str] | None,
    **kwargs: dict[str, Any],
) -> list[Error]:
    from django.db import connection

    if connection.vendor != "mysql":
        return []

    with connection.cursor() as cursor:
        cursor.execute(
            # Put the datatype lookup in a subquery. This is to make sure we get a
            # row back even when the "api_check" table does not exist yet.
            """
            SELECT VERSION(),
              (SELECT DATA_TYPE
               FROM INFORMATION_SCHEMA.COLUMNS
               WHERE TABLE_SCHEMA = DATABASE()
                 AND TABLE_NAME = 'api_check'
                 AND COLUMN_NAME = 'code')
            """
        )
        version, data_type = cursor.fetchone()
        if "MariaDB" not in version:
            return []

        version_parts = version.split(".")
        major, minor = int(version_parts[0]), int(version_parts[1])

        # If:
        # - we are using MariaDB 10.7+
        # - *and* the UUID columns exist and use a varchar datatype,
        # then we have a problem.
        if major >= 10 and minor >= 7 and data_type == "char":
            e = Error(
                "Detected MariaDB >= 10.7, a manual migration to UUID datatypes required",
                hint="See https://github.com/healthchecks/healthchecks/issues/929 for details",
                id="hc.api.E001",
            )
            return [e]

    return []