terraform {
  required_version = "~> 0.12.21"
  required_providers {
    azurerm = "~> 1.44"
  }
}

data "azurerm_virtual_machine" "vm" {
  count = length(var.vms)

  name                = var.vms[count.index].name
  resource_group_name = var.vms[count.index].resource_group_name
}

resource "azurerm_monitor_action_group" "azag" {
  count = length(var.ags)

  name                = var.ags[count.index].name
  resource_group_name = var.rg_name
  short_name          = var.ags[count.index].short_name

  email_receiver {
    name          = var.ags[count.index].email_name
    email_address = var.ags[count.index].email_address
  }

  tags = var.tags
}

locals {
  alerts = flatten([
    for azal in var.als : [
      for vm in data.azurerm_virtual_machine.vm : {
        name   = join(" on ", [azal.name,vm.name])
        scopes = vm.id
        description = azal.description
        frequency = azal.frequency
        window_size = azal.window_size
        severity = azal.severity
        metric_namespace = azal.metric_namespace
        metric_name = azal.metric_name
        aggregation = azal.aggregation
        operator = azal.operator
        threshold = azal.threshold
        actiongroup_id = azal.actiongroup_id
      }
    ]
  ])
}

resource "azurerm_monitor_metric_alert" "azalert" {

  for_each = {for alert in local.alerts: alert.name => alert}

  name                = each.key
  resource_group_name = var.rg_name
  scopes              = [ each.value.scopes ]
  description         = each.value.description
  frequency           = each.value.frequency
  window_size         = each.value.window_size
  severity            = each.value.severity

  criteria {
    metric_namespace = each.value.metric_namespace
    metric_name      = each.value.metric_name
    aggregation      = each.value.aggregation
    operator         = each.value.operator
    threshold        = each.value.threshold
  }

  action {
    action_group_id = element(azurerm_monitor_action_group.azag.*.id, each.value.actiongroup_id)
  }

  tags = var.tags

  depends_on = [var.azalert_depends_on]
}