locals {
  #################################################################
  # 1. Discover & decode alert YAML files from <root>/<alerts_dir>
  #################################################################
  alert_files = fileset(
    "${path.root}/${var.alerts_dir}",
    var.file_pattern
  )

  decoded_files = [
    for f in local.alert_files :
    yamldecode(file("${path.root}/${var.alerts_dir}/${f}"))
  ]

  #################################################################
  # 2. Flatten: each file may contain multiple groups
  #################################################################
  groups_raw = flatten([
    for doc in local.decoded_files : try(doc.groups, [])
  ])

  #################################################################
  # 3. Merge defaults & convert camelCase → snake_case
  #################################################################
  groups = [
    for g in local.groups_raw : merge(g, {
      uid = try(
        g.uid,
        trim(replace(replace(lower(g.name), " ", "-"), "_", "-"), "-")
      )
      folder_uid = try(try(g.folder_uid, g.folder), var.default_folder_uid)
      interval   = try(g.interval, "1m")

      rules = [
        for r in g.rules : merge(r, {
          data = [
            for d in r.data : merge(d, {
              datasource_uid      = try(d.datasourceUid, var.default_datasource_uid)
              relative_time_range = try(d.relativeTimeRange, { from = 600, to = 0 })
            })
          ]
        })
      ]
    })
  ]
}