{ pkgs, lib }:

with lib;

{ }: {
  inherit (pkgs.formats.json { }) type;

  generate = name: value: let
    valueToString = val:
      if val == null then
        "null"
      else if isString val then
         builtins.toJSON val
      else if isBool val then
        boolToString val
      else if isInt val || isFloat val then
        toString val
      else if isList val then
        "array(${concatMapStringsSep ", " valueToString val})"
      else if isAttrs val && val ? value && (val._type or "") == "raw" then
        val.value
      else if isAttrs val then
        throw "Found unexpected attrs, that were not created by mkRaw. Have you put attrs in an array?\n${val}"
      else throw "unsupported :')";

    flattenStructuredSettings = attrs: let
      partitionAttrs = pred: attrs: lib.pipe attrs [
        attrsToList
        (partition ({ name, value }: pred name value))
        (mapAttrs (_: listToAttrs))
      ];

      partitionedAttrs = partitionAttrs (_: v: isAttrs v && !(v ? value && (v._type or "") == "raw")) attrs;

      flattenedAttrs = lib.pipe partitionedAttrs.right [
        (mapAttrs (n1: mapAttrs' (n2: v2: nameValuePair "${n1}_${n2}" v2)))
        attrValues
        (map flattenStructuredSettings)
        (foldl recursiveUpdate { })
      ];
    in recursiveUpdate flattenedAttrs partitionedAttrs.wrong;

    content = lib.pipe value [
      flattenStructuredSettings
      (mapAttrs (_: valueToString))
      (mapAttrsToList (n: v: ''''$${n} = ${v};''))
      (concatStringsSep "\n")
      (content: "<?php\n${content}\n?>")
    ];
  in pkgs.writeText name content;

  lib = {
    mkRaw = value: {
      inherit value;
      _type = "raw";
    };

    types.raw = lib.types.attrs;
  };
}