import { Injectable } from '@angular/core';
import axios, { AxiosInstance, AxiosResponse } from 'axios';
import { environment } from 'src/environments/environment';

import { Poll } from '../models/poll.model';
import { User } from '../models/user.model';

@Injectable({
	providedIn: 'root',
})
export class ApiService {
	private axiosInstance: AxiosInstance;
	private readonly pollsEndpoint = environment.api.endpoints.polls.name;
	private readonly commentsEndpoint = environment.api.endpoints.polls.comments.name;
	private readonly votesEndpoint = environment.api.endpoints.polls.votes.name;
	private readonly slugsEndpoint = environment.api.endpoints.polls.slugs.name;
	private readonly votesStacksEndpoint = environment.api.endpoints.voteStack.name;
	private readonly usersEndpoint = environment.api.endpoints.users.name;
	private readonly usersPollsEndpoint = environment.api.endpoints.users.polls.name;
	private readonly usersPollsSendEmailEndpoint = environment.api.endpoints.users.polls.sendEmail.name;

	constructor() {
		this.axiosInstance = axios.create({ baseURL: environment.api.baseHref });
	}

	////////////
	// CREATE //
	////////////
	public async savePoll(poll: Poll): Promise<void> {
		try {
			await this.axiosInstance.post(`${this.pollsEndpoint}`, { params: { config: poll.config } });
		} catch (error) {
			this.handleError(error);
		}
	}

	public async saveVote(poll: Poll): Promise<void> {
		try {
			// TODO: add the votestack in the params
			await this.axiosInstance.post(`${this.pollsEndpoint}/${poll.id}${this.votesEndpoint}`, {
				params: { voteStack: {} },
			});
		} catch (error) {
			this.handleError(error);
		}
	}

	public async saveComment(poll: Poll, comment: string): Promise<void> {
		try {
			// TODO: add the comment in the params
			await this.axiosInstance.post(`${this.pollsEndpoint}/${poll.id}${this.commentsEndpoint}`, {
				params: { comment },
			});
		} catch (error) {
			this.handleError(error);
		}
	}

	//////////
	// READ //
	//////////
	public async isSlugAvailable(slug: string): Promise<boolean> {
		try {
			// TODO: scenario should be : if we can get this slug, it exists. if not, it doesn't. It's just a GET.
			const response: AxiosResponse = await this.axiosInstance.get(
				`${this.pollsEndpoint}${this.slugsEndpoint}/${slug}`
			);
			if (response?.status !== 404) {
				return false;
			}
		} catch (error) {
			if (error.response?.status === 404) {
				return true;
			} else {
				this.handleError(error);
			}
		}
	}

	public async sendEmailToUserOfItsPollsList(user: User): Promise<void> {
		// If user is not authenticated: the list of polls is send to user's email by the backend.
		try {
			await this.axiosInstance.get<Poll[]>(
				`${this.usersEndpoint}/${user.email}${this.usersPollsEndpoint}${this.usersPollsSendEmailEndpoint}`
			);
		} catch (error) {
			this.handleError(error);
		}
	}

	public async getPollsByUserEmail(user: User): Promise<Poll[]> {
		// If user is authenticated : retrieve polls & display directly in frontend.
		// TODO: Backend should handle this case. Actually the endpoint doesn't exist in backend.
		try {
			const response: AxiosResponse<Poll[]> = await this.axiosInstance.get<Poll[]>(
				`${this.usersEndpoint}/${user.email}${this.usersPollsEndpoint}`
			);
			return response?.data;
		} catch (error) {
			this.handleError(error);
		}
	}

	public async getPollByIdentifier(identifier: string): Promise<Poll | undefined> {
		// TODO: identifier should be decided according to backend : Id || Slug ?
		try {
			const response: AxiosResponse<Poll> = await this.axiosInstance.get<Poll>(
				`${this.pollsEndpoint}/${identifier}`
			);
			return response?.data;
		} catch (error) {
			if (error.response?.status === 404) {
				return undefined;
			} else {
				this.handleError(error);
			}
		}
	}

	////////////
	// UPDATE //
	////////////
	public async updatePoll(poll: Poll): Promise<void> {
		try {
			// TODO: implement the params when entities are finalized.
			await this.axiosInstance.put(`${this.pollsEndpoint}/${poll.id}`, {
				params: { voteStack: {}, token: '' },
			});
		} catch (error) {
			this.handleError(error);
		}
	}

	public async updateVote(voteStack: any): Promise<void> {
		try {
			// TODO: implement the params when entities are finalized.
			await this.axiosInstance.patch(`${this.votesStacksEndpoint}/${voteStack.id}`, {
				params: { voteStack: {}, token: '' },
			});
		} catch (error) {
			this.handleError(error);
		}
	}

	////////////
	// DELETE //
	////////////

	public async deletePoll(poll: Poll): Promise<void> {
		try {
			await this.axiosInstance.delete(`${this.pollsEndpoint}${poll.id}`, {});
		} catch (error) {
			this.handleError(error);
		}
	}

	public async deletePollVotes(poll: Poll): Promise<void> {
		try {
			// TODO: update endpoint in Backend
			await this.axiosInstance.delete(`${this.pollsEndpoint}${poll.id}${this.votesEndpoint}`);
		} catch (error) {
			this.handleError(error);
		}
	}

	public async deletePollComments(poll: Poll): Promise<void> {
		try {
			// TODO: modify endpoint in Backend
			await this.axiosInstance.delete(`${this.pollsEndpoint}${poll.id}${this.commentsEndpoint}`);
		} catch (error) {
			this.handleError(error);
		}
	}

	/////////////////////
	// PRIVATE METHODS //
	/////////////////////
	private handleError(error): void {
		if (error.response) {
			// The request was made and the server responded with a status code
			// that falls out of the range of 2xx
			console.log(error.response.data);
			console.log(error.response.status);
			console.log(error.response.headers);
		} else if (error.request) {
			// The request was made but no response was received
			// `error.request` is an instance of XMLHttpRequest in the browser and an instance of
			// http.ClientRequest in node.js
			console.log(error.request);
		} else {
			// Something happened in setting up the request that triggered an Error
			console.log('Error', error.message);
		}
		console.log(error.config);
	}
}