import Hook from '../hook';
import { API } from 'aws-amplify';
import {
    QueryRequest,
    QueryResponse,
    SaveRequest,
    SaveResponse,
    ErrorResponse,
    Response,
    HistoryRequest,
    HistoryResponse,
} from 'sync-ql';
import { equals } from 'sync-ql';

export const NoData = null as any;

export const defaultHeaders = {
    'Accept': 'application/json'
}

export type {
    QueryRequest,
    QueryResponse,
    SaveRequest,
    SaveResponse,
    HistoryRequest,
    HistoryResponse,
    ErrorResponse,
    Response
}

export abstract class Service {
    protected constructor(service: string) {
        this.cache = new CacheService(service);
        this.request = new RequestService(service);
    }

    protected readonly cache: CacheService;
    protected readonly request: RequestService;
}

class RequestService {
    constructor(private service: string) {
    }

    /****************************** METHODS ******************************/

    public async get<D = QueryResponse | SaveResponse | ErrorResponse>(url: string, params?: { [key: string]: string }, headers: { [key: string]: string } = defaultHeaders): Promise<Response<D>> {
        try {
            url = url.startsWith('/')
                ? url
                : `/${url}`
            const result = await API.get(this.service, url, {
                headers,
                queryStringParameters: params
            });
            return result
                ? result
                : { type: 500, data: NoData }
        }
        catch (err) {
            console.log(err);
            throw err;
        }
    }

    public async post<D = QueryResponse | SaveResponse | ErrorResponse>(url: string, params?: { [key: string]: string }, data?: any, headers: { [key: string]: string } = defaultHeaders): Promise<Response<D>> {
        try {
            url = url.startsWith('/')
                ? url
                : `/${url}`
            const result = await API.post(this.service, url, {
                headers,
                body: data,
                queryStringParameters: params
            });
            return result
                ? result
                : { type: 500, data: NoData }
        }
        catch (err) {
            console.log(err);
            throw err;
        }
    }

    public async put<D = QueryResponse | SaveResponse | ErrorResponse>(url: string, params?: { [key: string]: string }, data?: any, headers: { [key: string]: string } = defaultHeaders): Promise<Response<D>> {
        try {
            url = url.startsWith('/')
                ? url
                : `/${url}`
            const result = await API.put(this.service, url, {
                headers,
                body: data,
                queryStringParameters: params
            });
            return result
                ? result
                : { type: 500, data: NoData }
        }
        catch (err) {
            console.log(err);
            throw err;
        }
    }

    public async delete<D = QueryResponse | SaveResponse | ErrorResponse>(url: string, params?: { [key: string]: string }, headers: { [key: string]: string } = defaultHeaders): Promise<Response<D>> {
        try {
            url = url.startsWith('/')
                ? url
                : `/${url}`
            const result = await API.del(this.service, url, {
                headers,
                queryStringParameters: params
            });
            return result
                ? result
                : { type: 500, data: NoData }
        }
        catch (err) {
            console.log(err);
            throw err;
        }
    }
}

class CacheService {
    private cache: { [url: string]: any } = {}

    constructor(private service: string) {
    }

    /****************************** METHODS ******************************/

    public async get<D = QueryResponse | SaveResponse | ErrorResponse>(url: string, params?: { [key: string]: string }, headers: { [key: string]: string } = defaultHeaders): Promise<Response<D>> {
        url = url.startsWith('/')
            ? url
            : `/${url}`
        if (!this.cache[url]) {
            this.cache[url] = {
                context: {
                    method: 'get',
                    params: NoData,
                    data: NoData,
                },
                response: NoData,
                loading: false,
            }
        }
        if (this.cache[url].loading) {
            return this.cache[url].loading;
        }
        if (equals(this.cache[url].context, { method: 'get', params })) {
            return new Promise((resolve) => resolve(this.cache[url].response));
        }
        this.cache[url].context = { method: 'get', params }

        return (this.cache[url].loading = new Promise((resolve, reject) => {
            API.get(this.service, url, { headers, queryStringParameters: params })
                .then(result => {
                    this.cache[url].loading = false;

                    resolve(
                        result
                            ? this.cache[url].response = result
                            : { type: 500, data: NoData }
                    )
                })
                .catch(err => {
                    this.cache[url].loading = false;

                    reject(err)
                })
        })) as any;
    }

    public post<D = QueryResponse | SaveResponse | ErrorResponse>(url: string, params?: { [key: string]: string }, data?: any, headers: { [key: string]: string } = defaultHeaders): Promise<Response<D>> {
        url = url.startsWith('/')
            ? url
            : `/${url}`
        if (!this.cache[url]) {
            this.cache[url] = {
                context: {
                    method: 'post',
                    params: NoData,
                    data: NoData,
                },
                response: NoData,
                loading: false,
            }
        }
        if (this.cache[url].loading) {
            return this.cache[url].loading;
        }
        if (equals(this.cache[url].context, { method: 'post', params, data })) {
            return new Promise((resolve) => resolve(this.cache[url].response));
        }
        this.cache[url].context = { method: 'post', params, data }

        return (this.cache[url].loading = new Promise((resolve, reject) => {
            API.post(this.service, url, { headers, queryStringParameters: params, body: data })
                .then(result => {
                    this.cache[url].loading = false;

                    resolve(
                        result
                            ? this.cache[url].response = result
                            : { type: 500, data: NoData }
                    )
                })
                .catch(err => {
                    this.cache[url].loading = false;

                    reject(err)
                })
        })) as any;
    }

    public clear(url?: string) {
        if (url) {
            delete this.cache[url];
        }
        else this.cache = {}
    }
}

export const send = {
    request: async function load(callback: () => Promise<void>, loading?: 'DONT SHOW LOADING') {
        try {
            if (callback) {
                if (loading !== 'DONT SHOW LOADING') {
                    Hook.loading().start();
                }
                await callback();
            }
        }
        catch (err) {
            console.log(err)
        }
        finally {
            if (callback && loading !== 'DONT SHOW LOADING') {
                Hook.loading().stop();
            }
        }
    }
}