//
//  InterceptFetchRequestsJS.swift
//  flutter_inappwebview
//
//  Created by Lorenzo Pichilli on 16/02/21.
//

import Foundation

let INTERCEPT_FETCH_REQUEST_JS_PLUGIN_SCRIPT_GROUP_NAME = "IN_APP_WEBVIEW_INTERCEPT_FETCH_REQUEST_JS_PLUGIN_SCRIPT"
let FLAG_VARIABLE_FOR_SHOULD_INTERCEPT_FETCH_REQUEST_JS_SOURCE = "window.\(JAVASCRIPT_BRIDGE_NAME)._useShouldInterceptFetchRequest"

let INTERCEPT_FETCH_REQUEST_JS_PLUGIN_SCRIPT = PluginScript(
    groupName: INTERCEPT_FETCH_REQUEST_JS_PLUGIN_SCRIPT_GROUP_NAME,
    source: INTERCEPT_FETCH_REQUEST_JS_SOURCE,
    injectionTime: .atDocumentStart,
    forMainFrameOnly: false,
    requiredInAllContentWorlds: true,
    messageHandlerNames: [])

let INTERCEPT_FETCH_REQUEST_JS_SOURCE = """
\(FLAG_VARIABLE_FOR_SHOULD_INTERCEPT_FETCH_REQUEST_JS_SOURCE) = true;
(function(fetch) {
  if (fetch == null) {
    return;
  }
  function convertHeadersToJson(headers) {
    var headersObj = {};
    for (var header of headers.keys()) {
      var value = headers.get(header);
      headersObj[header] = value;
    }
    return headersObj;
  }
  function convertJsonToHeaders(headersJson) {
    return new Headers(headersJson);
  }
  function convertBodyToArray(body) {
    return new Response(body).arrayBuffer().then(function(arrayBuffer) {
      var arr = Array.from(new Uint8Array(arrayBuffer));
      return arr;
    })
  }
  function convertArrayIntBodyToUint8Array(arrayIntBody) {
    return new Uint8Array(arrayIntBody);
  }
  function convertCredentialsToJson(credentials) {
    var credentialsObj = {};
    if (window.FederatedCredential != null && credentials instanceof FederatedCredential) {
      credentialsObj.type = credentials.type;
      credentialsObj.id = credentials.id;
      credentialsObj.name = credentials.name;
      credentialsObj.protocol = credentials.protocol;
      credentialsObj.provider = credentials.provider;
      credentialsObj.iconURL = credentials.iconURL;
    } else if (window.PasswordCredential != null && credentials instanceof PasswordCredential) {
      credentialsObj.type = credentials.type;
      credentialsObj.id = credentials.id;
      credentialsObj.name = credentials.name;
      credentialsObj.password = credentials.password;
      credentialsObj.iconURL = credentials.iconURL;
    } else {
      credentialsObj.type = 'default';
      credentialsObj.value = credentials;
    }
  }
  function convertJsonToCredential(credentialsJson) {
    var credentials;
    if (window.FederatedCredential != null && credentialsJson.type === 'federated') {
      credentials = new FederatedCredential({
        id: credentialsJson.id,
        name: credentialsJson.name,
        protocol: credentialsJson.protocol,
        provider: credentialsJson.provider,
        iconURL: credentialsJson.iconURL
      });
    } else if (window.PasswordCredential != null && credentialsJson.type === 'password') {
      credentials = new PasswordCredential({
        id: credentialsJson.id,
        name: credentialsJson.name,
        password: credentialsJson.password,
        iconURL: credentialsJson.iconURL
      });
    } else {
      credentials = credentialsJson;
    }
    return credentials;
  }
  window.fetch = async function(resource, init) {
    if (\(FLAG_VARIABLE_FOR_SHOULD_INTERCEPT_FETCH_REQUEST_JS_SOURCE) == null || \(FLAG_VARIABLE_FOR_SHOULD_INTERCEPT_FETCH_REQUEST_JS_SOURCE) == true) {
      var fetchRequest = {
        url: null,
        method: null,
        headers: null,
        body: null,
        mode: null,
        credentials: null,
        cache: null,
        redirect: null,
        referrer: null,
        referrerPolicy: null,
        integrity: null,
        keepalive: null
      };
      if (resource instanceof Request) {
        fetchRequest.url = resource.url;
        fetchRequest.method = resource.method;
        fetchRequest.headers = resource.headers;
        fetchRequest.body = resource.body;
        fetchRequest.mode = resource.mode;
        fetchRequest.credentials = resource.credentials;
        fetchRequest.cache = resource.cache;
        fetchRequest.redirect = resource.redirect;
        fetchRequest.referrer = resource.referrer;
        fetchRequest.referrerPolicy = resource.referrerPolicy;
        fetchRequest.integrity = resource.integrity;
        fetchRequest.keepalive = resource.keepalive;
      } else {
        fetchRequest.url = resource;
        if (init != null) {
          fetchRequest.method = init.method;
          fetchRequest.headers = init.headers;
          fetchRequest.body = init.body;
          fetchRequest.mode = init.mode;
          fetchRequest.credentials = init.credentials;
          fetchRequest.cache = init.cache;
          fetchRequest.redirect = init.redirect;
          fetchRequest.referrer = init.referrer;
          fetchRequest.referrerPolicy = init.referrerPolicy;
          fetchRequest.integrity = init.integrity;
          fetchRequest.keepalive = init.keepalive;
        }
      }
      if (fetchRequest.headers instanceof Headers) {
        fetchRequest.headers = convertHeadersToJson(fetchRequest.headers);
      }
      fetchRequest.credentials = convertCredentialsToJson(fetchRequest.credentials);
      return convertBodyToArray(fetchRequest.body).then(function(body) {
        fetchRequest.body = body;
        return window.\(JAVASCRIPT_BRIDGE_NAME).callHandler('shouldInterceptFetchRequest', fetchRequest).then(function(result) {
          if (result != null) {
            switch (result.action) {
              case 0:
                var controller = new AbortController();
                if (init != null) {
                  init.signal = controller.signal;
                } else {
                  init = {
                    signal: controller.signal
                  };
                }
                controller.abort();
                break;
            }
            resource = (result.url != null) ? result.url : resource;
            if (init == null) {
              init = {};
            }
            if (result.method != null && result.method.length > 0) {
              init.method = result.method;
            }
            if (result.headers != null && Object.keys(result.headers).length > 0) {
              init.headers = convertJsonToHeaders(result.headers);
            }
            if (result.body != null && result.body.length > 0)   {
              init.body = convertArrayIntBodyToUint8Array(result.body);
            }
            if (result.mode != null && result.mode.length > 0) {
              init.mode = result.mode;
            }
            if (result.credentials != null) {
              init.credentials = convertJsonToCredential(result.credentials);
            }
            if (result.cache != null && result.cache.length > 0) {
              init.cache = result.cache;
            }
            if (result.redirect != null && result.redirect.length > 0) {
              init.redirect = result.redirect;
            }
            if (result.referrer != null && result.referrer.length > 0) {
              init.referrer = result.referrer;
            }
            if (result.referrerPolicy != null && result.referrerPolicy.length > 0) {
              init.referrerPolicy = result.referrerPolicy;
            }
            if (result.integrity != null && result.integrity.length > 0) {
              init.integrity = result.integrity;
            }
            if (result.keepalive != null) {
              init.keepalive = result.keepalive;
            }
            return fetch(resource, init);
          }
          return fetch(resource, init);
        });
      });
    } else {
      return fetch(resource, init);
    }
  };
})(window.fetch);
"""