howto.dhall

let Environment = < Staging | Preprod | Prod >

let TenantsPerEnvironment =
      { Staging = < Tenant1 >
      , Preprod = < Tenant1 | Tenant2 >
      , Prod = < Tenant2 >
      }

let tenantOf
    : Environment -> Type
    = \(environment : Environment) -> merge TenantsPerEnvironment environment

let TenantClusterAuth = { account : Text, token : Text }

let Handler =
      { Tenant1 : Optional TenantClusterAuth
      , Tenant2 : Optional TenantClusterAuth
      }

let tenantClusterAuthPerEnvironmentSome =
      { Staging =
        { Tenant1 = Some { account = "a", token = "b" }
        , Tenant2 = None TenantClusterAuth
        }
      , Preprod =
        { Tenant1 = Some { account = "c", token = "d" }
        , Tenant2 = Some { account = "e", token = "f" }
        }
      , Prod =
        { Tenant1 = None TenantClusterAuth
        , Tenant2 = Some { account = "g", token = "h" }
        }
      }

let tenantClusterAuthPerEnvironment =
      { Staging.Tenant1 = { account = "a", token = "b" }
      , Preprod =
        { Tenant1 = { account = "c", token = "d" }
        , Tenant2 = { account = "e", token = "f" }
        }
      , Prod.Tenant2 = Some { account = "g", token = "h" }
      }

let tenantClusterAuthOf =
      \(environment : Environment) ->
        let TenantUnion
            : Type
            = tenantOf environment

        in  \(admissableTenant : TenantUnion) ->
              let perEnv = merge tenantClusterAuthPerEnvironment environment

              in  merge perEnv admissableTenant

let tenantClusterAuthSomeOf =
      \(environment : Environment) ->
        let TenantUnion
            : Type
            = tenantOf environment

        in  \(admissableTenant : TenantUnion) ->
              let perEnv
                  : Handler
                  = merge tenantClusterAuthPerEnvironmentSome environment

              in  merge perEnv admissableTenant

in  tenantClusterAuthOf Environment.Preprod Tenants.Preprod.Tenant2