# Reusable Validation Library for Nickel
{
  IpV4Contract = {
    label = "ValidIPv4",
    predicate = fun ip =>
      std.string.is_match ip "^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$"
  },

  CidrContract = {
    label = "ValidCIDR",
    predicate = fun cidr =>
      std.string.is_match cidr "^\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}/\\d{1,2}$"
  },

  PortContract = {
    label = "ValidPort",
    predicate = fun p =>
      p > 0 && p < 65536
  },

  SemverContract = {
    label = "ValidSemver",
    predicate = fun v =>
      std.string.is_match v "^\\d+\\.\\d+\\.\\d+$"
  },

  DomainContract = {
    label = "ValidDomain",
    predicate = fun d =>
      std.string.is_match d "^[a-z0-9]([a-z0-9-\\.]{0,253}[a-z0-9])?$"
  },

  OciTagContract = {
    label = "ValidOCITag",
    predicate = fun tag =>
      std.string.is_match tag "^[a-zA-Z0-9_][a-zA-Z0-9._-]{0,127}$"
  },

  Iso8601Contract = {
    label = "ValidISO8601",
    predicate = fun ts =>
      std.string.is_match ts "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}Z$"
  },

  PathContract = {
    label = "ValidPath",
    predicate = fun path =>
      std.string.length path > 0 && !std.string.contains path "//"
  },

  min_length = fun min_val => {
    label = "MinLength%{std.to_string min_val}",
    predicate = fun s => std.string.length s >= min_val,
  },

  max_length = fun max_val => {
    label = "MaxLength%{std.to_string max_val}",
    predicate = fun s => std.string.length s <= max_val,
  },

  range = fun min_val max_val => {
    label = "Range[%{std.to_string min_val}-%{std.to_string max_val}]",
    predicate = fun n => n >= min_val && n <= max_val,
  },

  enum = fun values => {
    label = "Enum[%{std.string.join "," values}]",
    predicate = fun v => std.array.elem v values,
  },

  non_empty_string = {
    label = "NonEmptyString",
    predicate = fun s => std.string.length s > 0
  },

  non_negative = {
    label = "NonNegative",
    predicate = fun n => n >= 0
  },

  positive = {
    label = "Positive",
    predicate = fun n => n > 0
  },

  boolean_value = {
    label = "Boolean",
    predicate = fun b => b == true || b == false
  },

  all_items = fun pred => fun items => std.array.all pred items,

  any_items = fun pred => fun items => std.array.any pred items,

  has_keys = fun required_keys => fun record =>
    std.array.all
      (fun key => std.record.has_field record key)
      required_keys,

  IpRef =
    std.contract.custom (
      fun _label =>
        fun value =>
          if value == ""
            || std.string.is_match "^(\\d{1,3}\\.){3}\\d{1,3}$" value
            || std.string.contains ":" value
            || std.string.contains "fip" value
          then 'Ok value
          else 'Error {
            message = "expected empty, an IPv4 address, an IPv6 address (contains ':'), or a FIP name (contains 'fip'); got '%{value}'"
          }
    ),
}