# main.tf

# Step 1: Create all Grafana data sources with their basic configuration.
# This resource establishes the fundamental properties of each data source.
resource "grafana_data_source" "this" {
  for_each = var.datasources

  name     = each.key
  type     = each.value.type
  url      = var.datasource_urls[each.value.url_key]
  is_default = coalesce(each.value.is_default, false)

  basic_auth_enabled  = true
  basic_auth_username = var.datasource_users[each.value.user_key]

  secure_json_data_encoded = jsonencode({
    basicAuthPassword = var.datasource_passwords[each.value.pass_key]
  })

  # Encodes initial, non-dependent JSON data.
  # Configurations that depend on other datasource UIDs will be handled separately.
  json_data_encoded = each.value.json_data != null ? jsonencode(each.value.json_data) : null
}

# Step 2: Apply Loki-specific 'derivedFields' configuration.
# This resource targets Loki data sources that need to link to another data source (like Tempo).
# It runs after the initial data sources are created to resolve the UIDs.
resource "grafana_data_source_config" "loki_derived_fields" {
  # Filter for datasources that are of type 'loki' and have 'derived_fields' defined.
  for_each = {
    for k, v in var.datasources : k => v
    if v.type == "loki" && v.derived_fields != null
  }

  # The UID of the Loki data source to configure.
  uid = grafana_data_source.this[each.key].uid

  # Construct the json_data with the derivedFields.
  json_data_encoded = jsonencode({
    derivedFields = [
      for field in each.value.derived_fields : {
        # The UID of the target data source (e.g., Tempo).
        datasourceUid = grafana_data_source.this[field.target_datasource_name].uid
        matcherRegex  = field.matcher_regex
        name          = field.name
        url           = field.url
      }
    ]
  })
}

# Step 3: Apply Tempo-specific 'tracesToLogsV2' configuration.
# This resource targets Tempo data sources that need to link back to a logging data source (like Loki).
resource "grafana_data_source_config" "tempo_traces_to_logs" {
  # Filter for datasources that are of type 'tempo' and have 'traces_to_logs' defined.
  for_each = {
    for k, v in var.datasources : k => v
    if v.type == "tempo" && v.traces_to_logs != null
  }

  # The UID of the Tempo data source to configure.
  uid = grafana_data_source.this[each.key].uid

  # Construct the json_data with the tracesToLogsV2 settings.
  json_data_encoded = jsonencode({
    tracesToLogsV2 = {
      # The UID of the target data source (e.g., Loki).
      datasourceUid      = grafana_data_source.this[each.value.traces_to_logs.target_datasource_name].uid
      query              = each.value.traces_to_logs.query
      customQuery        = coalesce(each.value.traces_to_logs.custom_query, true)
      filterBySpanID     = coalesce(each.value.traces_to_logs.filter_by_span_id, false)
      filterByTraceID    = coalesce(each.value.traces_to_logs.filter_by_trace_id, false)
      spanStartTimeShift = each.value.traces_to_logs.span_start_time_shift
      spanEndTimeShift   = each.value.traces_to_logs.span_end_time_shift
    }
  })
}