import deepmerge from 'deepmerge';
import isPlainObject from 'is-plain-object';
import urlTemplate from 'url-template';
import getUserAgent from 'universal-user-agent';

function _slicedToArray(arr, i) {
  return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _nonIterableRest();
}

function _arrayWithHoles(arr) {
  if (Array.isArray(arr)) return arr;
}

function _iterableToArrayLimit(arr, i) {
  var _arr = [];
  var _n = true;
  var _d = false;
  var _e = undefined;

  try {
    for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) {
      _arr.push(_s.value);

      if (i && _arr.length === i) break;
    }
  } catch (err) {
    _d = true;
    _e = err;
  } finally {
    try {
      if (!_n && _i["return"] != null) _i["return"]();
    } finally {
      if (_d) throw _e;
    }
  }

  return _arr;
}

function _nonIterableRest() {
  throw new TypeError("Invalid attempt to destructure non-iterable instance");
}

function lowercaseKeys(object) {
  if (!object) {
    return {};
  }

  return Object.keys(object).reduce((newObj, key) => {
    newObj[key.toLowerCase()] = object[key];
    return newObj;
  }, {});
}

function merge(defaults, route, options) {
  if (typeof route === "string") {
    let _route$split = route.split(" "),
        _route$split2 = _slicedToArray(_route$split, 2),
        method = _route$split2[0],
        url = _route$split2[1];

    options = Object.assign(url ? {
      method,
      url
    } : {
      url: method
    }, options);
  } else {
    options = route || {};
  } // lowercase header names before merging with defaults to avoid duplicates


  options.headers = lowercaseKeys(options.headers);
  const mergedOptions = deepmerge.all([defaults, options].filter(Boolean), {
    isMergeableObject: isPlainObject
  }); // mediaType.previews arrays are merged, instead of overwritten

  if (defaults && defaults.mediaType.previews.length) {
    mergedOptions.mediaType.previews = defaults.mediaType.previews.filter(preview => !mergedOptions.mediaType.previews.includes(preview)).concat(mergedOptions.mediaType.previews);
  }

  mergedOptions.mediaType.previews = mergedOptions.mediaType.previews.map(preview => preview.replace(/-preview/, ""));
  return mergedOptions;
}

function addQueryParameters(url, parameters) {
  const separator = /\?/.test(url) ? "&" : "?";
  const names = Object.keys(parameters);

  if (names.length === 0) {
    return url;
  }

  return url + separator + names.map(name => {
    if (name === "q") {
      return "q=" + parameters.q.split("+").map(encodeURIComponent).join("+");
    }

    return "".concat(name, "=").concat(encodeURIComponent(parameters[name]));
  }).join("&");
}

const urlVariableRegex = /\{[^}]+\}/g;

function removeNonChars(variableName) {
  return variableName.replace(/^\W+|\W+$/g, "").split(/,/);
}

function extractUrlVariableNames(url) {
  const matches = url.match(urlVariableRegex);

  if (!matches) {
    return [];
  }

  return matches.map(removeNonChars).reduce((a, b) => a.concat(b), []);
}

function omit(object, keysToOmit) {
  return Object.keys(object).filter(option => !keysToOmit.includes(option)).reduce((obj, key) => {
    obj[key] = object[key];
    return obj;
  }, {});
}

function parse(options) {
  // https://fetch.spec.whatwg.org/#methods
  let method = options.method.toUpperCase(); // replace :varname with {varname} to make it RFC 6570 compatible

  let url = options.url.replace(/:([a-z]\w+)/g, "{+$1}");
  let headers = Object.assign({}, options.headers);
  let body;
  let parameters = omit(options, ["method", "baseUrl", "url", "headers", "request", "mediaType"]); // extract variable names from URL to calculate remaining variables later

  const urlVariableNames = extractUrlVariableNames(url);
  url = urlTemplate.parse(url).expand(parameters);

  if (!/^http/.test(url)) {
    url = options.baseUrl + url;
  }

  const omittedParameters = Object.keys(options).filter(option => urlVariableNames.includes(option)).concat("baseUrl");
  const remainingParameters = omit(parameters, omittedParameters);
  const isBinaryRequset = /application\/octet-stream/i.test(headers.accept);

  if (!isBinaryRequset) {
    if (options.mediaType.format) {
      // e.g. application/vnd.github.v3+json => application/vnd.github.v3.raw
      headers.accept = headers.accept.split(/,/).map(preview => preview.replace(/application\/vnd(\.\w+)(\.v3)?(\.\w+)?(\+json)?$/, "application/vnd$1$2.".concat(options.mediaType.format))).join(",");
    }

    if (options.mediaType.previews.length) {
      const previewsFromAcceptHeader = headers.accept.match(/[\w-]+(?=-preview)/g) || [];
      headers.accept = previewsFromAcceptHeader.concat(options.mediaType.previews).map(preview => {
        const format = options.mediaType.format ? ".".concat(options.mediaType.format) : "+json";
        return "application/vnd.github.".concat(preview, "-preview").concat(format);
      }).join(",");
    }
  } // for GET/HEAD requests, set URL query parameters from remaining parameters
  // for PATCH/POST/PUT/DELETE requests, set request body from remaining parameters


  if (["GET", "HEAD"].includes(method)) {
    url = addQueryParameters(url, remainingParameters);
  } else {
    if ("data" in remainingParameters) {
      body = remainingParameters.data;
    } else {
      if (Object.keys(remainingParameters).length) {
        body = remainingParameters;
      } else {
        headers["content-length"] = 0;
      }
    }
  } // default content-type for JSON if body is set


  if (!headers["content-type"] && typeof body !== "undefined") {
    headers["content-type"] = "application/json; charset=utf-8";
  } // GitHub expects 'content-length: 0' header for PUT/PATCH requests without body.
  // fetch does not allow to set `content-length` header, but we can set body to an empty string


  if (["PATCH", "PUT"].includes(method) && typeof body === "undefined") {
    body = "";
  } // Only return body/request keys if present


  return Object.assign({
    method,
    url,
    headers
  }, typeof body !== "undefined" ? {
    body
  } : null, options.request ? {
    request: options.request
  } : null);
}

function endpointWithDefaults(defaults, route, options) {
  return parse(merge(defaults, route, options));
}

function withDefaults(oldDefaults, newDefaults) {
  const DEFAULTS = merge(oldDefaults, newDefaults);
  const endpoint = endpointWithDefaults.bind(null, DEFAULTS);
  return Object.assign(endpoint, {
    DEFAULTS,
    defaults: withDefaults.bind(null, DEFAULTS),
    merge: merge.bind(null, DEFAULTS),
    parse
  });
}

const VERSION = "0.0.0-development";

const userAgent = "octokit-endpoint.js/".concat(VERSION, " ").concat(getUserAgent());
const DEFAULTS = {
  method: "GET",
  baseUrl: "https://api.github.com",
  headers: {
    accept: "application/vnd.github.v3+json",
    "user-agent": userAgent
  },
  mediaType: {
    format: "",
    previews: []
  }
};

const endpoint = withDefaults(null, DEFAULTS);

export { endpoint };