<%
const { apiConfig, generateResponses, config } = it;
%>

export type QueryParamsType = Record<string | number, any>;
export type ResponseFormat = keyof Omit<Body, "body" | "bodyUsed">;

export interface FullRequestParams extends Omit<RequestInit, "body"> {
  /** set parameter to `true` for call `securityWorker` for this request */
  secure?: boolean;
  /** request path */
  path: string;
  /** content type of request body */
  type?: ContentType;
  /** query params */
  query?: QueryParamsType;
  /** format of response (i.e. response.json() -> format: "json") */
  format?: ResponseFormat;
  /** request body */
  body?: unknown;
  /** base url */
  baseUrl?: string;
  /** request cancellation token */
  cancelToken?: CancelToken;
}

export type RequestParams = Omit<FullRequestParams, "body" | "method" | "path">


export interface ApiConfig<SecurityDataType = unknown> {
    baseUrl?: string;
    baseApiParams?: Omit<RequestParams, "baseUrl" | "cancelToken" | "signal">;
    securityWorker?: (securityData: SecurityDataType | null) => Promise<RequestParams | void> | RequestParams | void;
    customFetch?: typeof fetch;
}

export interface HttpResponse<D extends unknown, E extends unknown = unknown> extends Response {
    data: D;
    error: E;
}

type CancelToken = Symbol | string | number;

export enum ContentType {
    Json = "application/json",
    FormData = "multipart/form-data",
    UrlEncoded = "application/x-www-form-urlencoded",
}

export class HttpClient<SecurityDataType = unknown> {
    public baseUrl: string = "<%~ apiConfig.baseUrl %>";
    private securityData: SecurityDataType | null = null;
    private securityWorker?: ApiConfig<SecurityDataType>["securityWorker"];
    private abortControllers = new Map<CancelToken, AbortController>();
    private customFetch = (...fetchParams: Parameters<typeof fetch>) => fetch(...fetchParams);

    private baseApiParams: RequestParams = {
        credentials: 'same-origin',
        headers: {},
        redirect: 'follow',
        referrerPolicy: 'no-referrer',
    }

    constructor(apiConfig: ApiConfig<SecurityDataType> = {}) {
        Object.assign(this, apiConfig);
    }

    public setSecurityData = (data: SecurityDataType | null) => {
        this.securityData = data;
    }

    private encodeQueryParam(key: string, value: any) {
        const encodedKey = encodeURIComponent(key);
        return `${encodedKey}=${encodeURIComponent(typeof value === "number" ? value : `${value}`)}`;
    }

    private addQueryParam(query: QueryParamsType, key: string) {
        return this.encodeQueryParam(key, query[key]);
    }

    private addArrayQueryParam(query: QueryParamsType, key: string) {
        const value = query[key];
        return value.map((v: any) => this.encodeQueryParam(key, v)).join("&");
    }

    protected toQueryString(rawQuery?: QueryParamsType): string {
        const query = rawQuery || {};
        const keys = Object.keys(query).filter((key) => "undefined" !== typeof query[key]);
        return keys
                .map((key) =>
                    Array.isArray(query[key])
                    ? this.addArrayQueryParam(query, key)
                    : this.addQueryParam(query, key),
                )
                .join("&");
    }

    protected addQueryParams(rawQuery?: QueryParamsType): string {
        const queryString = this.toQueryString(rawQuery);
        return queryString ? `?${queryString}` : "";
    }

    private contentFormatters: Record<ContentType, (input: any) => any> = {
        [ContentType.Json]: (input:any) => input !== null && (typeof input === "object" || typeof input === "string") ? JSON.stringify(input) : input,
        [ContentType.FormData]: (input: any) =>
            Object.keys(input || {}).reduce((formData, key) => {
                const property = input[key];
                formData.append(
                    key,
                    property instanceof Blob ?
                        property :
                    typeof property === "object" && property !== null ?
                        JSON.stringify(property) :
                    `${property}`
                );
                return formData;
            }, new FormData()),
        [ContentType.UrlEncoded]: (input: any) => this.toQueryString(input),
    }

    private mergeRequestParams(params1: RequestParams, params2?: RequestParams): RequestParams {
        return {
            ...this.baseApiParams,
            ...params1,
            ...(params2 || {}),
            headers: {
                ...(this.baseApiParams.headers || {}),
                ...(params1.headers || {}),
                ...((params2 && params2.headers) || {}),
            },
        };
    }

    private createAbortSignal = (cancelToken: CancelToken): AbortSignal | undefined => {
        if (this.abortControllers.has(cancelToken)) {
            const abortController = this.abortControllers.get(cancelToken);
            if (abortController) {
                return abortController.signal;
            }
            return void 0;
        }

        const abortController = new AbortController();
        this.abortControllers.set(cancelToken, abortController);
        return abortController.signal;
    }

    public abortRequest = (cancelToken: CancelToken) => {
        const abortController = this.abortControllers.get(cancelToken)

        if (abortController) {
            abortController.abort();
            this.abortControllers.delete(cancelToken);
        }
    }

    public request = async <T = any, E = any>({
        body,
        secure,
        path,
        type,
        query,
        format,
        baseUrl,
        cancelToken,
        ...params
<% if (config.unwrapResponseData) { %>
    }: FullRequestParams): Promise<T> => {
<% } else { %>
    }: FullRequestParams): Promise<HttpResponse<T, E>> => {
<% } %>
        const secureParams = ((typeof secure === 'boolean' ? secure : this.baseApiParams.secure) && this.securityWorker && await this.securityWorker(this.securityData)) || {};
        const requestParams = this.mergeRequestParams(params, secureParams);
        const queryString = query && this.toQueryString(query);
        const payloadFormatter = this.contentFormatters[type || ContentType.Json];
        const responseFormat = format || requestParams.format;

        return this.customFetch(
        `${baseUrl || this.baseUrl || ""}${path}${queryString ? `?${queryString}` : ""}`,
        {
            ...requestParams,
            headers: {
            ...(type && type !== ContentType.FormData ? { "Content-Type": type } : {}),
            ...(requestParams.headers || {}),
            },
            signal: cancelToken ? this.createAbortSignal(cancelToken) : void 0,
            body: typeof body === "undefined" || body === null ? null : payloadFormatter(body),
        }
        ).then(async (response) => {
            const r = response as HttpResponse<T, E>;
            r.data = (null as unknown) as T;
            r.error = (null as unknown) as E;

            const data = !responseFormat ? r : await response[responseFormat]()
                .then((data) => {
                    if (r.ok) {
                        r.data = data;
                    } else {
                        r.error = data;
                    }
                    return r;
                })
                .catch((e) => {
                    r.error = e;
                    return r;
                });

            if (cancelToken) {
                this.abortControllers.delete(cancelToken);
            }

            if (!response.ok) throw data;
<% if (config.unwrapResponseData) { %>
            return data.data;
<% } else { %>
            return data;
<% } %>
        });
    };
}