//
//  ScientificCalculatorViewController.swift
//  Swift iOS Calculator
//
//  Created by RSK World on 23/01/2026.
//  Copyright © 2026 RSK World. All rights reserved.
//
//  Developer: Molla Samser (Founder, RSK World)
//  Designer & Tester: Rima Khatun
//  Contact: info@rskworld.com, +91 93305 39277
//  Website: https://rskworld.in
//  Address: Nutanhat, Mongolkote, Purba Burdwan, West Bengal, India - 713147
//

import UIKit

class ScientificCalculatorViewController: UIViewController {
    
    // MARK: - Outlets
    @IBOutlet weak var displayLabel: UILabel!
    @IBOutlet weak var secondaryDisplayLabel: UILabel!
    
    // MARK: - Properties
    private var calculator = CalculatorLogic()
    private var isUserTyping = false
    private var isScientificMode = false
    
    // MARK: - Lifecycle
    override func viewDidLoad() {
        super.viewDidLoad()
        setupUI()
    }
    
    // MARK: - UI Setup
    private func setupUI() {
        displayLabel.text = "0"
        displayLabel.font = UIFont.systemFont(ofSize: 42, weight: .light)
        displayLabel.textAlignment = .right
        displayLabel.textColor = .label
        
        secondaryDisplayLabel.text = ""
        secondaryDisplayLabel.font = UIFont.systemFont(ofSize: 18, weight: .regular)
        secondaryDisplayLabel.textAlignment = .right
        secondaryDisplayLabel.textColor = .secondaryLabel
    }
    
    // MARK: - Basic Number Actions
    @IBAction func numberButtonPressed(_ sender: UIButton) {
        guard let number = sender.currentTitle else { return }
        
        if isUserTyping {
            if displayLabel.text != "0" {
                displayLabel.text?.append(number)
            } else {
                displayLabel.text = number
            }
        } else {
            displayLabel.text = number
            isUserTyping = true
        }
    }
    
    @IBAction func operationButtonPressed(_ sender: UIButton) {
        guard let operation = sender.currentTitle else { return }
        
        if isUserTyping {
            calculator.setNumber(displayLabel.text ?? "0")
            isUserTyping = false
        }
        
        updateSecondaryDisplay(operation)
        
        if let result = calculator.calculate(symbol: operation) {
            displayLabel.text = formatNumber(result)
        } else {
            displayLabel.text = "Error"
        }
    }
    
    @IBAction func clearButtonPressed(_ sender: UIButton) {
        displayLabel.text = "0"
        secondaryDisplayLabel.text = ""
        isUserTyping = false
        calculator.clear()
    }
    
    @IBAction func decimalButtonPressed(_ sender: UIButton) {
        if isUserTyping && !(displayLabel.text?.contains(".") ?? true) {
            displayLabel.text?.append(".")
        } else if !isUserTyping {
            displayLabel.text = "0."
            isUserTyping = true
        }
    }
    
    @IBAction func plusMinusButtonPressed(_ sender: UIButton) {
        guard let currentText = displayLabel.text, currentText != "0" else { return }
        
        if currentText.hasPrefix("-") {
            displayLabel.text = String(currentText.dropFirst())
        } else {
            displayLabel.text = "-" + currentText
        }
    }
    
    @IBAction func percentageButtonPressed(_ sender: UIButton) {
        guard let currentText = displayLabel.text,
              let number = Double(currentText) else { return }
        
        let result = number / 100
        displayLabel.text = formatNumber(result)
        isUserTyping = false
    }
    
    // MARK: - Scientific Function Actions
    @IBAction func scientificFunctionPressed(_ sender: UIButton) {
        guard let function = sender.currentTitle else { return }
        
        if isUserTyping {
            calculator.setNumber(displayLabel.text ?? "0")
            isUserTyping = false
        }
        
        updateSecondaryDisplay(function)
        
        if let result = calculator.performScientificOperation(function) {
            displayLabel.text = formatNumber(result)
        } else {
            displayLabel.text = "Error"
        }
    }
    
    @IBAction func memoryFunctionPressed(_ sender: UIButton) {
        guard let memoryFunction = sender.currentTitle else { return }
        
        switch memoryFunction {
        case "MC":
            calculator.memoryClear()
        case "MR":
            if let memoryValue = calculator.memoryRecall() {
                displayLabel.text = formatNumber(memoryValue)
                isUserTyping = false
            }
        case "M+":
            if let currentText = displayLabel.text, let number = Double(currentText) {
                calculator.memoryAdd(number)
            }
        case "M-":
            if let currentText = displayLabel.text, let number = Double(currentText) {
                calculator.memorySubtract(number)
            }
        default:
            break
        }
    }
    
    @IBAction func constantButtonPressed(_ sender: UIButton) {
        guard let constant = sender.currentTitle else { return }
        
        switch constant {
        case "π":
            displayLabel.text = formatNumber(.pi)
            isUserTyping = false
        case "e":
            displayLabel.text = formatNumber(.e)
            isUserTyping = false
        default:
            break
        }
    }
    
    // MARK: - Helper Methods
    private func formatNumber(_ number: Double) -> String {
        if number.isNaN || number.isInfinite {
            return "Error"
        }
        
        if number.truncatingRemainder(dividingBy: 1) == 0 {
            return String(Int(number))
        } else {
            return String(number)
        }
    }
    
    private func updateSecondaryDisplay(_ operation: String) {
        if let currentText = displayLabel.text {
            secondaryDisplayLabel.text = "\(currentText) \(operation)"
        }
    }
    
    // MARK: - Mode Toggle
    @IBAction func toggleCalculatorMode(_ sender: UIButton) {
        isScientificMode.toggle()
        // Update UI to show/hide scientific buttons
        // This would typically involve showing/hiding constraints or views
    }
}