//
//  EmployeeService.swift
//  EmployeeDirectory
//
//  Created by Matt Bruce on 3/3/25.
//
import Foundation

public class EmployeeService: EmployeeServiceProtocol {
    // MARK: - Properties
    public static let shared = EmployeeService() // Default shared instance
    
    // MARK: - Initializer
    
    public init() {}
    
    // MARK: - Public Methods
    
    /// This will get a list of all employees
    /// - Returns: An Employees struct
    public func getUsers(page: Int? = nil) async throws -> Employees {
        var endpoint = "https://my.api.mockaroo.com/users.json?key=f298b840"
        if let page {
            endpoint += "&page=\(page)"
        }
        
        //ensure a valid URL
        guard let url = URL(string: endpoint) else {
            throw URLError(.badURL)
        }

        // Perform network request
        let (data, response) = try await URLSession.shared.data(from: url)
        
        // Validate HTTP response
        guard let httpResponse = response as? HTTPURLResponse,
              200..<300 ~= httpResponse.statusCode else {
            throw URLError(.badServerResponse)
        }
        
        // Decode the response into the specified type
        return try JSONDecoder().decode(Employees.self, from: data)
    }
}

// Mock Service Implementation for testing & previews.
struct MockEmployeeService: EmployeeServiceProtocol {
    static let sample = createUser(page: 1, index: 1)
    
    static func createUser(page: Int?, index: Int) -> Employee {
        Employee(
            uuid: UUID(),
            firstName: "First \(index + ((page ?? 1) - 1) * 20)",
            lastName: "Last \(index + ((page ?? 1) - 1) * 20)",
            phoneNumber: "555555\(1000 + index)",
            emailAddress: "user\(index)@example.com",
            biography: "Biography for employee \(index)",
            photoURLSmall: "https://example.com/photo_small.jpg",
            photoURLLarge: "https://example.com/photo_large.jpg"
        )
    }
    func getUsers(page: Int?) async throws -> Employees {
        // Simulate network delay.
        try await Task.sleep(nanoseconds: 500_000_000)
        
        // Create dummy data (20 employees per page).
        let dummyEmployees: [Employee] = (0..<20).map { i in
            Self.createUser(page: page, index: i)
        }
        
        // Simulate that there are more pages if page is less than 5.
        let hasNext = (page ?? 1) < 5
        
        return Employees(result: dummyEmployees, hasNextPage: hasNext)
    }
}