let
  lib = import <nixpkgs/lib>;

  validateFile = siteName: index: file:
    let
      _ = if builtins.isAttrs file then null else throw "web.${siteName}.files[${toString index}] must be an attrset.";
      __ = if file ? path && builtins.isString file.path then null else throw "web.${siteName}.files[${toString index}].path must be a string.";
      ___ = if file ? content && builtins.isString file.content then null else throw "web.${siteName}.files[${toString index}].content must be a string.";
      ____ = if file ? contentType && builtins.isString file.contentType && file.contentType != "" then null else throw "web.${siteName}.files[${toString index}].contentType must be a non-empty string.";
      _____ = if file ? status && builtins.isInt file.status then null else throw "web.${siteName}.files[${toString index}].status must be an int.";
    in
      file;

  validateSite = siteName: site:
    let
      _ = if builtins.isAttrs site then null else throw "web.${siteName} must be an attrset.";
      __ = if site ? files && builtins.isList site.files then null else throw "web.${siteName}.files must be a list.";
      ___ = lib.imap0 (index: file: validateFile siteName index file) site.files;
    in
      site;

  getWebConfig = webConfig:
    if builtins.isAttrs webConfig then
      lib.mapAttrs validateSite webConfig
    else
      throw "config/web.nix must evaluate to an attrset.";
in
{
  inherit getWebConfig;
}