#include <GxEPD.h>
#include <GxFont_GFX.h>


#include <GxGDEM029T94/GxGDEM029T94.h>
#include <GxIO/GxIO_SPI/GxIO_SPI.h>
#include <GxIO/GxIO.h>
#include <SPI.h>
#include <Fonts/FreeMonoBold9pt7b.h>
#include <Fonts/FreeMonoBold12pt7b.h>
#include <SD.h>  // Include the SD library

#define CS1   5   // Chip select for display 1
#define DC1   22  // Data/Command for display 1
#define RSET1 21  // Reset for display 1
#define BUSY1 4   // Busy for display 1

#define CS2   15  // Chip select for display 2
#define DC2   2   // Data/Command for display 2
#define RSET2 0   // Reset for display 2
#define BUSY2 16  // Busy for display 2

#define MOSI 23  // Data in
#define SCLK 18  // Clock
#define CS_PIN 33 // Chip select for SD card

#define BUTTON_UP 12    // GPIO pin for the "up" button
#define BUTTON_DOWN 13  // GPIO pin for the "down" button
#define BUTTON_SELECT 14 // GPIO pin for the "select" button

GxIO_Class io1(SPI, CS1, DC1, RSET1);
GxEPD_Class display1(io1, RSET1, BUSY1);

GxIO_Class io2(SPI, CS2, DC2, RSET2);
GxEPD_Class display2(io2, RSET2, BUSY2);

const char TextBsp[] = "Irgendein Text";

int cnt;

File root; // Declare the root variable

File currentFile; // Declare the current file variable
int selectedFileIndex = 0; // Index of the selected file
int totalFiles = 0; // Total number of files
String fileNames[100]; // Array to store file names
int scrollPosition = 0; // Scroll position for reading text

void printDirectory(File dir, int numTabs, int &line);
void displayText(File file, int scrollPosition);
void printDirectory(File dir, int numTabs, int &line);

// will need to display 20 lins of text at a time.  The screen on top will hold 10 inds of text
// the bottom screen will hold the next 10 lines of text.

void displayFileList();
void displayText(File file, int scrollPosition);

void setup() {
  Serial.begin(115200);
  SPI.begin(SCLK, MISO, MOSI);
  display1.init();
  display2.init();

  pinMode(BUTTON_UP, INPUT_PULLUP);
  pinMode(BUTTON_DOWN, INPUT_PULLUP);
  pinMode(BUTTON_SELECT, INPUT_PULLUP);

  display1.setRotation(1);
  display1.fillScreen(GxEPD_WHITE);
  display1.setTextColor(GxEPD_BLACK);
  display1.setFont(&FreeMonoBold9pt7b);
  display1.setCursor(10, 30);
  display1.print("Initializing SD card... ");
  display1.update();

  display2.setRotation(1);
  display2.fillScreen(GxEPD_WHITE);
  display2.setTextColor(GxEPD_BLACK);
  display2.setFont(&FreeMonoBold9pt7b);
  display2.setCursor(10, 30);
  display2.println("sheppard semiconductor");
  display2.setCursor(20, 40);
  display2.println("systems");
  display2.update();

  if (!SD.begin(CS_PIN)) {
    Serial.println("Card initialization failed!");
    display1.println("Card initialization failed!");
    display1.update();
    while (true);
  }

  Serial.println("initialization done.");
  display1.println("initialization done.");
  display1.update();

  Serial.println("Files in the card:");
  display2.println("Files in the card:");

  display1.fillScreen(GxEPD_WHITE);
  display1.setCursor(10, 30);
  display1.setFont(&FreeMonoBold9pt7b);
  display1.println("Sheppard Semiconductor");
  display1.setCursor(10, 40);
  display1.println("Systems");
  display1.setCursor(10, 60);
  display1.println("What book would you like to read?");
  display1.update();

  root = SD.open("/");
  int line = 0;
  display2.fillScreen(GxEPD_WHITE);
  display2.setTextColor(GxEPD_BLACK);
  display2.setFont(&FreeMonoBold9pt7b);
  display2.setCursor(10, 30);
  printDirectory(root, 0, line);
  display2.update();
}

 void displayFileList() {
    display2.fillScreen(GxEPD_WHITE);
    display2.setCursor(10, 30);
    for (int i = 0; i < totalFiles; i++) {
      if (i == selectedFileIndex) {
        display2.setTextColor(GxEPD_BLACK, GxEPD_WHITE); // Highlight selected file
      } else {
        display2.setTextColor(GxEPD_BLACK);
      }
      display2.println(fileNames[i]);
    }
    display2.update();
  };

  void displayText(File file, int scrollPosition) {
    display1.fillScreen(GxEPD_WHITE);
    display2.fillScreen(GxEPD_WHITE);
    display1.setCursor(10, 30);
    display2.setCursor(10, 30);
    display1.setTextColor(GxEPD_BLACK);
    display2.setTextColor(GxEPD_BLACK);
    display1.setFont(&FreeMonoBold9pt7b);
    display2.setFont(&FreeMonoBold9pt7b);

    int line = 0;
    int charCount = 0;
    file.seek(scrollPosition); // Start reading from the scroll position

    while (file.available()) {
      char c = file.read();
      if (line < 10) {
        display1.write(c);
      } else if (line < 20) {
        display2.write(c);
      }
      charCount++;
      if (c == '\n') {
        line++;
        if (line == 10) {
          display1.update();
        } else if (line == 20) {
          display2.update();
          break; // Stop reading after 20 lines
        }
      }
    }
  };
  void printDirectory(File dir, int numTabs, int &line) {
    while (true) {
      File entry = dir.openNextFile();
      if (!entry) {
        // no more files
        break;
      }
      if (!entry.isDirectory()) {
        fileNames[totalFiles] = entry.name();
        totalFiles++;
      }
      entry.close();
    }
    displayFileList();
  };

  
void loop() {
    if (digitalRead(BUTTON_UP) == LOW) {
        selectedFileIndex = max(0, selectedFileIndex - 1);
        
        delay(200); // Debounce delay
      }
      if (digitalRead(BUTTON_DOWN) == LOW) {
        selectedFileIndex = min(totalFiles - 1, selectedFileIndex + 1);
        
        delay(200); // Debounce delay
      }
      if (digitalRead(BUTTON_SELECT) == LOW) {
        currentFile = SD.open(fileNames[selectedFileIndex]);
        scrollPosition = 0;
        displayText(currentFile, scrollPosition);
        delay(200); // Debounce delay
      }
      if (digitalRead(BUTTON_UP) == HIGH && currentFile) {
        scrollPosition = max(0, scrollPosition - 200); // Adjust scroll amount as needed
        displayText(currentFile, scrollPosition);
        delay(200); // Debounce delay
      }
      if (digitalRead(BUTTON_DOWN) == HIGH && currentFile) {
        scrollPosition += 200; // Adjust scroll amount as needed
        displayText(currentFile, scrollPosition);
        delay(200); // Debounce delay
      }


    // Update the scroll position for the next read
    //scrollPosition += charCount;
    display1.update();
    display2.update();
  };