//
//  APIClient.swift
//  APIService
//
//  Created by Javier Cicchelli on 04/12/2022.
//  Copyright © 2022 Röck+Cöde. All rights reserved.
//

import Foundation

struct APIClient {
    private let session: URLSession
    private let decoder: JSONDecoder
    private let makeURLRequest: MakeURLRequestUseCase
}

// MARK: - Initialisers

extension APIClient {
    init(configuration: URLSessionConfiguration = .default) {
        self.session = .init(configuration: configuration)
        self.decoder = .init()
        self.makeURLRequest = .init()
    }
}


// MARK: - Client

extension APIClient: Client {
    func request<Model>(
        endpoint: some Endpoint,
        model: Model.Type
    ) async throws -> Model where Model : Decodable {
        let urlRequest = try makeURLRequest(endpoint: endpoint)
        let (data, response) = try await session.data(for: urlRequest)
        
        guard
            let httpResponse = response as? HTTPURLResponse,
            let responseStatus = ResponseStatus(rawValue: httpResponse.statusCode)
        else {
            throw APIClientError.responseNotReturned
        }
        
        switch responseStatus {
        case .ok,
            .created:
            return try await decode(data, as: model)
        case .noContent:
            throw APIClientError.notSupported
        case .badRequest:
            throw APIClientError.itemAlreadyExist
        case .notFound:
            throw APIClientError.itemDoesNotExist
        }
    }
    
    @discardableResult
    func request(
        endpoint: some Endpoint
    ) async throws -> Data {
        let urlRequest = try makeURLRequest(endpoint: endpoint)
        let (data, response) = try await session.data(for: urlRequest)
        
        guard
            let httpResponse = response as? HTTPURLResponse,
            let responseStatus = ResponseStatus(rawValue: httpResponse.statusCode)
        else {
            throw APIClientError.responseNotReturned
        }
        
        switch responseStatus {
        case .ok,
             .noContent:
            return data
        case .created:
            throw APIClientError.notSupported
        case .badRequest:
            throw APIClientError.itemIsNotFile
        case .notFound:
            throw APIClientError.itemDoesNotExist
        }
    }
}

// MARK: - Helpers

private extension APIClient {
    func decode<Model: Decodable>(
        _ data: Data,
        as model: Model.Type
    ) async throws -> Model {
        do {
            decoder.dateDecodingStrategy = .formatted(.isoZulu)
            
            return try decoder.decode(model, from: data)
        } catch {
            decoder.dateDecodingStrategy = .iso8601
            
            return try decoder.decode(model, from: data)
        }
    }
}

// MARK: - Errors

public enum APIClientError: Error {
    case responseNotReturned
    case itemIsNotFile
    case itemAlreadyExist
    case itemDoesNotExist
    case notSupported
}