pi/validation/endpoints.nix

let
  lib = import <nixpkgs/lib>;

  allowedEndpointKeys = [ "type" "domain" "endpoint" "port" "force_ssl" "content" ];
  allowedProxyContentKeys = [ "type" "ip" "port" "proxyWebsockets" ];
  allowedWebContentKeys = [ "type" "files" ];
  allowedWebFileKeys = [ "path" "filePath" "contentType" "status" ];

  ensureNoUnknownKeys = context: obj: allowedKeys:
    let
      unknown = builtins.filter (key: !(lib.elem key allowedKeys)) (builtins.attrNames obj);
    in
      if unknown != [] then
        throw "${context} contains unknown keys: ${builtins.concatStringsSep ", " unknown}"
      else
        obj;

  ensurePath = value:
    builtins.isString value
    && builtins.substring 0 1 value == "/";

  ensurePort = value:
    builtins.isInt value && value > 0 && value <= 65535;

  validateEndpointShape = index: endpoint:
    let
      _ = if !builtins.isAttrs endpoint then throw "Endpoint at index ${toString index} must be an attrset." else null;
      __ = ensureNoUnknownKeys "Endpoint at index ${toString index}" endpoint allowedEndpointKeys;
      ___ =
        if endpoint ? forceSsl then
          throw "Endpoint at index ${toString index} uses forceSsl. Use force_ssl instead."
        else
          null;
      typeValue =
        if endpoint ? type && builtins.isString endpoint.type then
          endpoint.type
        else
          throw "Endpoint at index ${toString index} must define type as a string.";
      _type =
        if lib.elem typeValue [ "proxy" "web" ] then
          null
        else
          throw "Endpoint at index ${toString index} type must be 'proxy' or 'web'.";
      _domain =
        if endpoint ? domain && builtins.isString endpoint.domain && endpoint.domain != "" then
          null
        else
          throw "Endpoint at index ${toString index} must define a non-empty domain string.";
      _endpoint =
        if endpoint ? endpoint && ensurePath endpoint.endpoint then
          null
        else
          throw "Endpoint at index ${toString index} must define endpoint as a path starting with '/'.";
      _port =
        if endpoint ? port && ensurePort endpoint.port then
          null
        else
          throw "Endpoint at index ${toString index} must define port as int in range 1..65535.";
      _forceSsl =
        if endpoint ? force_ssl && builtins.isBool endpoint.force_ssl then
          null
        else
          throw "Endpoint at index ${toString index} must define force_ssl as a bool.";
      contentValue =
        if endpoint ? content && builtins.isAttrs endpoint.content then
          endpoint.content
        else
          throw "Endpoint at index ${toString index} must define content as an attrset.";
      _content =
        if typeValue == "proxy" then
          let
            ____ = ensureNoUnknownKeys "Proxy content at endpoint index ${toString index}" contentValue allowedProxyContentKeys;
          in
            if !(contentValue ? type) || !builtins.isString contentValue.type then
              throw "Proxy endpoint at index ${toString index} must define content.type as a string."
            else if !(contentValue ? ip) || !builtins.isString contentValue.ip || contentValue.ip == "" then
              throw "Proxy endpoint at index ${toString index} must define content.ip as a non-empty string."
            else if !(contentValue ? port) || !ensurePort contentValue.port then
              throw "Proxy endpoint at index ${toString index} must define content.port as int in range 1..65535."
            else if !(contentValue ? proxyWebsockets) || !builtins.isBool contentValue.proxyWebsockets then
              throw "Proxy endpoint at index ${toString index} must define content.proxyWebsockets as a bool."
            else
              null
        else
          let
            ____ = ensureNoUnknownKeys "Web content at endpoint index ${toString index}" contentValue allowedWebContentKeys;
            filesValue =
              if contentValue ? files && builtins.isList contentValue.files then
                contentValue.files
              else
                throw "Web endpoint at index ${toString index} must define content.files as a list.";
            _____ =
              if contentValue ? type && contentValue.type == "store" then
                null
              else
                throw "Web endpoint at index ${toString index} must define content.type = 'store'.";
            ______ = lib.imap0 (fileIndex: file:
              let
                _______ =
                  if builtins.isAttrs file then
                    null
                  else
                    throw "Web endpoint at index ${toString index} file at position ${toString fileIndex} must be an attrset.";
                ________ = ensureNoUnknownKeys "Web endpoint at index ${toString index} file at position ${toString fileIndex}" file allowedWebFileKeys;
                _________ =
                  if file ? path && builtins.isString file.path && file.path != "" && builtins.substring 0 1 file.path != "/" then
                    null
                  else
                    throw "Web endpoint at index ${toString index} file at position ${toString fileIndex} must define path as a relative path string.";
                __________ =
                  if file ? filePath && (builtins.isString file.filePath || builtins.isPath file.filePath) then
                    null
                  else
                    throw "Web endpoint at index ${toString index} file at position ${toString fileIndex} must define filePath as string or path.";
                ___________ =
                  if file ? contentType && builtins.isString file.contentType && file.contentType != "" then
                    null
                  else
                    throw "Web endpoint at index ${toString index} file at position ${toString fileIndex} must define contentType as non-empty string.";
                ____________ =
                  if file ? status && builtins.isInt file.status then
                    null
                  else
                    throw "Web endpoint at index ${toString index} file at position ${toString fileIndex} must define status as int.";
              in
                file
            ) filesValue;
          in
            null;
    in
      endpoint;

  validateEndpointsShape = endpoints:
    if !builtins.isList endpoints then
      throw "config/endpoints.nix must evaluate to a list of endpoint attrsets."
    else
      lib.imap0 validateEndpointShape endpoints;
in
{
  inherit validateEndpointShape validateEndpointsShape;
}