/*
 * Squidex Headless CMS
 *
 * @license
 * Copyright (c) Squidex UG (haftungsbeschränkt). All rights reserved.
 */

import { HttpClient, HttpErrorResponse, HttpHeaders, HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs';

import { Version } from './../utils/version';

export class Versioned<T> {
    constructor(
        public readonly version: Version,
        public readonly payload: T
    ) {
    }
}

function formatMessage(message: string, details?: string[]) {
    const appendLast = (row: string, char: string) => {
        const last = row[row.length - 1];

        if (last !== char) {
            return row + char;
        } else {
            return row;
        }
    };

    const removeLast = (row: string, char: string) => {
        const last = row[row.length - 1];

        if (last === char) {
            return row.substr(0, row.length - 1);
        } else {
            return row;
        }
    };

    if (details && details.length > 1) {
        let result = appendLast(message, '.') + '<ul>';

        for (let detail of details) {
            result += `<li>${appendLast(detail, '.')}</li>`;
        }

        result = result + '</ul>';

        return result;
    } else if (details && details.length === 1) {
        return `${appendLast(removeLast(message, '.'), ':')} ${appendLast(details[0], '.')}`;
    } else {
        return appendLast(message, '.');
    }
}

export class ErrorDto {
    public readonly displayMessage: string;

    constructor(
        public readonly statusCode: number,
        public readonly message: string,
        public readonly details: string[] = []
    ) {
        this.displayMessage = formatMessage(message, details);
    }
}

export module HTTP {
    export function getVersioned<T>(http: HttpClient, url: string, version?: Version): Observable<Versioned<HttpResponse<T>>> {
        const headers = createHeaders(version);

        return handleVersion(http.get<T>(url, { observe: 'response', headers }), version);
    }

    export function postVersioned<T>(http: HttpClient, url: string, body: any, version?: Version): Observable<Versioned<HttpResponse<T>>> {
        const headers = createHeaders(version);

        return handleVersion(http.post<T>(url, body, { observe: 'response', headers }), version);
    }

    export function putVersioned<T>(http: HttpClient, url: string, body: any, version?: Version): Observable<Versioned<HttpResponse<T>>> {
        const headers = createHeaders(version);

        return handleVersion(http.put<T>(url, body, { observe: 'response', headers }), version);
    }

    export function deleteVersioned<T>(http: HttpClient, url: string, version?: Version): Observable<Versioned<HttpResponse<T>>> {
        const headers = createHeaders(version);

        return handleVersion(http.delete<T>(url, { observe: 'response', headers }), version);
    }

    function createHeaders(version?: Version): HttpHeaders {
        if (version && version.value && version.value.length > 0) {
            return new HttpHeaders().set('If-Match', version.value);
        } else {
            return new HttpHeaders();
        }
    }

    function handleVersion<T>(httpRequest: Observable<HttpResponse<T>>, version?: Version): Observable<Versioned<HttpResponse<T>>> {
        return httpRequest.map((response: HttpResponse<T>) => {
            const etag = response.headers.get('etag') || '';

            return new Versioned(new Version(etag), response);
        });
    }
}

export function pretifyError(message: string): Observable<any> {
    return this.catch((response: HttpErrorResponse) => {
        let result: ErrorDto | null = null;

        if (!(response.error instanceof Error)) {
            try {
                const errorDto = typeof response.error === 'object' ? response.error : JSON.parse(response.error);

                if (response.status === 412) {
                    result = new ErrorDto(response.status, 'Failed to make the update. Another user has made a change. Please reload.');
                } else if (response.status !== 500) {
                    result = new ErrorDto(response.status, errorDto.message, errorDto.details);
                }
            } catch (e) {
                result = new ErrorDto(500, 'Failed to make the request.');
            }
        }

        result = result || new ErrorDto(500, message);

        return Observable.throw(result);
    });
}