resource "google_monitoring_uptime_check_config" "forgejo" {
  display_name = "Forgejo /api/v1/version"
  timeout      = "10s"
  period       = "60s"

  http_check {
    path           = "/api/v1/version"
    port           = "443"
    use_ssl        = true
    validate_ssl   = true
    request_method = "GET"
  }

  monitored_resource {
    type = "uptime_url"
    labels = {
      project_id = var.project_id
      host       = var.domain
    }
  }
}

resource "google_monitoring_alert_policy" "forgejo_down" {
  display_name = "Forgejo is down"
  combiner     = "OR"

  conditions {
    display_name = "Uptime check failing for 5+ min"
    condition_threshold {
      filter = join(" AND ", [
        "resource.type=\"uptime_url\"",
        "metric.type=\"monitoring.googleapis.com/uptime_check/check_passed\"",
        "metric.label.\"check_id\"=\"${google_monitoring_uptime_check_config.forgejo.uptime_check_id}\"",
      ])
      duration        = "300s"
      comparison      = "COMPARISON_GT"
      threshold_value = 1

      aggregations {
        alignment_period     = "1200s"
        per_series_aligner   = "ALIGN_NEXT_OLDER"
        cross_series_reducer = "REDUCE_COUNT_FALSE"
        group_by_fields      = ["resource.label.host"]
      }

      trigger {
        count = 1
      }
    }
  }

  notification_channels = [google_monitoring_notification_channel.email.id]

  alert_strategy {
    auto_close = "1800s"
  }
}

resource "google_monitoring_alert_policy" "tls_cert_expiry" {
  display_name = "Forgejo TLS cert expiring soon"
  combiner     = "OR"

  conditions {
    display_name = "Cert expires in <7 days"
    condition_threshold {
      filter = join(" AND ", [
        "resource.type=\"uptime_url\"",
        "metric.type=\"monitoring.googleapis.com/uptime_check/time_until_ssl_cert_expires\"",
        "metric.label.\"check_id\"=\"${google_monitoring_uptime_check_config.forgejo.uptime_check_id}\"",
      ])
      duration        = "600s"
      comparison      = "COMPARISON_LT"
      threshold_value = 7

      aggregations {
        alignment_period   = "1200s"
        per_series_aligner = "ALIGN_NEXT_OLDER"
      }
    }
  }

  notification_channels = [google_monitoring_notification_channel.email.id]

  alert_strategy {
    auto_close = "86400s"
  }
}

resource "google_logging_metric" "forgejo_disk_high" {
  name   = "forgejo_disk_high"
  filter = "resource.type=\"gce_instance\" AND jsonPayload.MESSAGE=~\"^DISK_HIGH:\""

  metric_descriptor {
    metric_kind = "DELTA"
    value_type  = "INT64"
  }
}

resource "google_monitoring_alert_policy" "disk_full" {
  display_name = "Forgejo data disk >80% full"
  combiner     = "OR"

  conditions {
    display_name = "DISK_HIGH log line emitted"
    condition_threshold {
      filter          = "resource.type=\"gce_instance\" AND metric.type=\"logging.googleapis.com/user/forgejo_disk_high\""
      duration        = "0s"
      comparison      = "COMPARISON_GT"
      threshold_value = 0

      aggregations {
        alignment_period     = "3600s"
        per_series_aligner   = "ALIGN_COUNT"
        cross_series_reducer = "REDUCE_SUM"
      }
    }
  }

  notification_channels = [google_monitoring_notification_channel.email.id]

  alert_strategy {
    auto_close = "86400s"
  }

  depends_on = [google_logging_metric.forgejo_disk_high]
}

resource "google_logging_metric" "forgejo_panic" {
  name = "forgejo_panic"
  filter = join(" AND ", [
    "resource.type=\"gce_instance\"",
    "logName=~\"projects/.*/logs/cos_containers\"",
    "(textPayload=~\"panic\" OR textPayload=~\"FATAL\" OR jsonPayload.message=~\"panic\" OR jsonPayload.message=~\"FATAL\")",
  ])

  metric_descriptor {
    metric_kind = "DELTA"
    value_type  = "INT64"
  }
}

resource "google_monitoring_alert_policy" "forgejo_panic" {
  display_name = "Forgejo container panic/FATAL"
  combiner     = "OR"

  conditions {
    display_name = "panic or FATAL in container logs"
    condition_threshold {
      filter          = "resource.type=\"gce_instance\" AND metric.type=\"logging.googleapis.com/user/forgejo_panic\""
      duration        = "0s"
      comparison      = "COMPARISON_GT"
      threshold_value = 0

      aggregations {
        alignment_period     = "300s"
        per_series_aligner   = "ALIGN_COUNT"
        cross_series_reducer = "REDUCE_SUM"
      }
    }
  }

  notification_channels = [google_monitoring_notification_channel.email.id]

  alert_strategy {
    auto_close = "3600s"
  }

  depends_on = [google_logging_metric.forgejo_panic]
}