import axios, { AxiosResponse, AxiosInstance, AxiosRequestConfig } from 'axios';

export type ClientEvent = 'expire';

export class HTTP {
    client: AxiosInstance;
    handlers: {
        [eventName: string]: Set<() => unknown>;
    };

    constructor(token: string, private baseUrl = 'https://taskforge.io/api') {
        this.handlers = {};
        this.client = axios.create({
            baseURL: this.baseUrl,
            validateStatus: (status) => {
                return status < 500;
            },
            headers:
                token !== '' && token
                    ? { authorization: `Bearer ${token}` }
                    : {}
        });
    }

    on(eventName: ClientEvent, handler: () => unknown) {
        const currentSet = this.handlers[eventName] ?? new Set();
        this.handlers[eventName] = currentSet.add(handler);
    }

    unsubscribe(eventName: ClientEvent, handler: () => unknown) {
        if (!this.handlers[eventName]) return;
        this.handlers[eventName].delete(handler);
    }

    fire(eventName: ClientEvent) {
        this.handlers[eventName].forEach((handler) => handler());
    }

    setToken(token: string) {
        this.client = axios.create({
            baseURL: this.baseUrl,
            headers: { authorization: `Bearer ${token}` }
        });
    }

    async request(config: AxiosRequestConfig): Promise<AxiosResponse<any>> {
        const response = await this.client.request(config);
        if (
            response.status === 401 &&
            config.url!.indexOf('tokens') === -1 &&
            !config.url!.endsWith('me')
        ) {
            const refreshed = await this.client.post('/v1/tokens/refresh');
            if (refreshed.status == 401) {
                await this.client.delete('/v1/tokens');
                this.fire('expire');
                throw new Error('session expired');
            }

            return await this.client.request(config);
        }

        return response;
    }

    async get(url: string, options?: AxiosRequestConfig) {
        return this.request({
            ...options,
            method: 'GET',
            url
        });
    }

    async delete(url: string, options?: AxiosRequestConfig) {
        return this.request({
            ...options,
            method: 'DELETE',
            url
        });
    }

    async put(url: string, data?: any) {
        return this.request({
            method: 'PUT',
            url,
            data
        });
    }

    async patch(url: string, data?: any) {
        return this.request({
            method: 'PATCH',
            url,
            data
        });
    }

    async post(url: string, data?: any) {
        return this.request({
            method: 'POST',
            url,
            data
        });
    }
}