/**
 * @file TouchscreenUI.h
 * @brief Touchscreen user interface for locomotive test bench
 * 
 * Provides a graphical interface on the ILI9341 TFT display with touch controls for:
 * - Power ON/OFF button
 * - DCC/Analog mode switching
 * - Speed slider (0-100%)
 * - 2-rail/3-rail configuration selector
 * - Direction control
 * - Status display
 * 
 * @author Locomotive Test Bench Project
 * @date 2025
 */

#ifndef TOUCHSCREEN_UI_H
#define TOUCHSCREEN_UI_H

#include <Arduino.h>
#include <TFT_eSPI.h>
#include <XPT2046_Touchscreen.h>
#include "Config.h"
#include "MotorController.h"
#include "DCCGenerator.h"
#include "RelayController.h"

// Touch calibration values for ESP32-2432S028R
#define TS_MIN_X 200
#define TS_MAX_X 3700
#define TS_MIN_Y 200
#define TS_MAX_Y 3750

// UI Colors
#define COLOR_BG 0x0000          // Black
#define COLOR_PANEL 0x2945       // Dark gray
#define COLOR_TEXT 0xFFFF        // White
#define COLOR_POWER_ON 0x07E0    // Green
#define COLOR_POWER_OFF 0xF800   // Red
#define COLOR_DCC 0x07FF         // Cyan
#define COLOR_ANALOG 0xFFE0      // Yellow
#define COLOR_SLIDER 0x435C      // Gray
#define COLOR_SLIDER_ACTIVE 0x07E0  // Green
#define COLOR_BUTTON 0x4A49      // Button gray
#define COLOR_BUTTON_ACTIVE 0x2124  // Darker gray
#define COLOR_FUNCTION_OFF 0x31A6   // Dark blue-gray
#define COLOR_FUNCTION_ON 0xFD20    // Orange

/**
 * @struct Button
 * @brief Simple button structure for touch areas
 */
struct Button {
    int16_t x, y, w, h;
    String label;
    uint16_t color;
    bool visible;
};

/**
 * @class TouchscreenUI
 * @brief Manages touchscreen display and user interactions
 * 
 * Provides complete UI for controlling the locomotive test bench,
 * handling touch events, updating displays, and coordinating with
 * motor controller, DCC generator, and relay controller.
 */
class TouchscreenUI {
public:
    /**
     * @brief Constructor
     * @param cfg Pointer to configuration object
     * @param motor Pointer to motor controller
     * @param dcc Pointer to DCC generator
     * @param relay Pointer to relay controller
     */
    TouchscreenUI(Config* cfg, MotorController* motor, DCCGenerator* dcc, RelayController* relay);
    
    /**
     * @brief Initialize touchscreen and display
     * 
     * Sets up TFT display, touch controller, and draws initial UI.
     */
    void begin();
    
    /**
     * @brief Update UI and handle touch events
     * 
     * Must be called regularly from main loop.
     * Handles touch detection, UI updates, and state changes.
     */
    void update();
    
    /**
     * @brief Force full screen redraw
     */
    void redraw();
    
    /**
     * @brief Get power state
     * @return true if power is ON
     */
    bool isPowerOn() { return powerOn; }
    
private:
    TFT_eSPI tft;
    XPT2046_Touchscreen touch;
    
    Config* config;
    MotorController* motorController;
    DCCGenerator* dccGenerator;
    RelayController* relayController;
    
    bool powerOn;
    uint8_t lastSpeed;
    bool lastDirection;
    bool lastIsDCC;
    bool lastIs3Rail;
    uint32_t lastDccFunctions;
    
    // Programming screen state
    bool programmingMode;
    uint16_t cvNumber;
    uint8_t cvValue;
    uint16_t newAddress;
    uint8_t keypadMode;  // 0=address, 1=CV number, 2=CV value
    
    // UI element positions
    Button btnPower;
    Button btnMode;
    Button btnRails;
    Button btnDirection;
    Button btnDccAddress;
    
    // DCC function buttons (F0-F12)
    #define NUM_FUNCTIONS 13
    Button btnFunctions[NUM_FUNCTIONS];
    
    // Programming mode buttons
    Button btnProgramming;
    Button btnProgBack;
    Button btnFactoryReset;
    Button btnSetAddress;
    Button btnReadCV;
    Button btnWriteCV;
    
    // Numeric keypad (0-9, backspace, enter)
    #define NUM_KEYPAD_BUTTONS 12
    Button btnKeypad[NUM_KEYPAD_BUTTONS];
    
    // Slider position and state
    int16_t sliderX, sliderY, sliderW, sliderH;
    int16_t sliderKnobX;
    bool sliderPressed;
    
    // Private methods
    void drawUI();
    void drawPowerButton();
    void drawModeButton();
    void drawRailsButton();
    void drawDirectionButton();
    void drawSpeedSlider();
    void drawStatusBar();
    void drawDccFunctions();
    void drawDccAddressButton();
    void drawProgrammingScreen();
    void drawNumericKeypad();
    void drawProgrammingStatus();
    
    void handleTouch(int16_t x, int16_t y);
    void updatePowerState(bool state);
    void updateMode(bool isDCC);
    void updateRailMode(bool is3Rail);
    void updateDirection();
    void updateSpeed(uint8_t newSpeed);
    void toggleDccFunction(uint8_t function);
    void enterProgrammingMode();
    void exitProgrammingMode();
    void handleKeypadPress(uint8_t key);
    void performFactoryReset();
    void performSetAddress();
    void performReadCV();
    void performWriteCV();
    
    int16_t mapTouch(int16_t value, int16_t inMin, int16_t inMax, int16_t outMin, int16_t outMax);
};

#endif // TOUCHSCREEN_UI_H