/*
 * Copyright (C) EdgeTX
 *
 * Based on code named
 *   opentx - https://github.com/opentx/opentx
 *   th9x - http://code.google.com/p/th9x
 *   er9x - http://code.google.com/p/er9x
 *   gruvin9x - http://code.google.com/p/gruvin9x
 *
 * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include "edgetx.h"

constexpr uint32_t TEXT_FILE_MAXSIZE = 2048;
constexpr char CHECKABLE_PREFIX = '=';
int checklistPosition;

static void sdReadTextFile(const char * filename, char lines[TEXT_VIEWER_LINES][LCD_COLS + 1], int & lines_count)
{
  FIL file;
  int result;
  char c;
  unsigned int sz;
  int line_length = 0;
  uint8_t escape = 0;
  char escape_chars[4] = {0};
  int current_line = 0;

  memclear(lines, TEXT_VIEWER_LINES * (LCD_COLS + 1));

  result = f_open(&file, filename, FA_OPEN_EXISTING | FA_READ);
  if (result == FR_OK) {
    for (uint32_t i = 0; i < TEXT_FILE_MAXSIZE && f_read(&file, &c, 1, &sz) == FR_OK && sz == 1 && (lines_count == 0 || current_line - menuVerticalOffset < int(TEXT_VIEWER_LINES)); i++) {
      if (c == '\n') {
        ++current_line;
        line_length = 0;
        escape = 0;
      }
      else if (c != '\r' && current_line >= menuVerticalOffset && current_line - menuVerticalOffset < int(TEXT_VIEWER_LINES) && line_length < LCD_COLS) {
        if (c == '\\' && escape == 0) {
          escape = 1;
          continue;
        }
        else if (c != '\\' && escape > 0 && escape < sizeof(escape_chars)) {
          escape_chars[escape - 1] = c;
          if (escape == 2 && !strncmp(escape_chars, "up", 2)) {
            lines[current_line-menuVerticalOffset][line_length++] = CHAR_UP[0];
            c = CHAR_UP[1];
          }
          else if (escape == 2 && !strncmp(escape_chars, "dn", 2)) {
            lines[current_line-menuVerticalOffset][line_length++] = CHAR_DOWN[0];
            c = CHAR_DOWN[1];
          }
          else if (escape == 3) {
            int val = atoi(escape_chars);
            if (val >= 200 && val < 225) {
              lines[current_line-menuVerticalOffset][line_length++] = '\302';
              c = '\200' + val - 200;
            }
          }
          else {
            escape++;
            continue;
          }
        }
        else if (c=='~') {
          c = 'z'+1;
        }
        else if (c=='\t') {
          c = 0x1D; //tab
        }
        escape = 0;
        lines[current_line-menuVerticalOffset][line_length++] = c;
      }
    }
    if (c != '\n') {
      current_line += 1;
    }
    f_close(&file);
  }

  if (lines_count == 0) {
    lines_count = current_line;
  }
}

void readModelNotes()
{
  LED_ERROR_BEGIN();

  strcpy(reusableBuffer.viewText.filename, MODELS_PATH "/");
  char *buf = strcat_currentmodelname(
      &reusableBuffer.viewText.filename[sizeof(MODELS_PATH)], 0);
  strcpy(buf, TEXT_EXT);

  if (!isFileAvailable(reusableBuffer.viewText.filename)) {
    buf = strcat_currentmodelname(
        &reusableBuffer.viewText.filename[sizeof(MODELS_PATH)], ' ');
    strcpy(buf, TEXT_EXT);

#if defined(STORAGE_MODELSLIST)
    if (!isFileAvailable(reusableBuffer.viewText.filename)) {
      buf = strAppendFilename(
          &reusableBuffer.viewText.filenam[sizeof(MODELS_PATH)],
          g_eeGeneral.currModelFilename, LEN_MODEL_FILENAME);
      strcpy(buf, TEXT_EXT);
    }
#endif
  }

  waitKeysReleased();
  event_t event = EVT_ENTRY;
  reusableBuffer.viewText.pushMenu = false;
  while (true) {
    uint32_t power = pwrCheck();
    if (power != e_power_press) {
      lcdRefreshWait();
      lcdClear();
      menuTextView(event);
      lcdRefresh();
    }
    if (power == e_power_off){
      drawSleepBitmap();
      boardOff();
      break;
    }
    event = getEvent();
    WDG_RESET();
    if (reusableBuffer.viewText.checklistComplete) break;
  }

  LED_ERROR_END();
}

void menuTextView(event_t event)
{
  if (event == EVT_ENTRY) {
      menuVerticalOffset = 0;
	  checklistPosition = 0;
      reusableBuffer.viewText.checklistComplete = false;
      reusableBuffer.viewText.linesCount = 0;
      sdReadTextFile(reusableBuffer.viewText.filename, reusableBuffer.viewText.lines, reusableBuffer.viewText.linesCount);
  } else if (IS_PREVIOUS_EVENT(event)) {
    if (menuVerticalOffset > 0) {
      menuVerticalOffset--;
      sdReadTextFile(reusableBuffer.viewText.filename, reusableBuffer.viewText.lines, reusableBuffer.viewText.linesCount);
    }
  } else if (IS_NEXT_EVENT(event)) {
    if (menuVerticalOffset + LCD_LINES-1 < reusableBuffer.viewText.linesCount) {
      ++menuVerticalOffset;
      sdReadTextFile(reusableBuffer.viewText.filename, reusableBuffer.viewText.lines, reusableBuffer.viewText.linesCount);
    }
  } else if (event == EVT_KEY_BREAK(KEY_ENTER)) {
    if (g_model.checklistInteractive && !reusableBuffer.viewText.pushMenu && checklistPosition-(int)menuVerticalOffset >= 0){
      if (checklistPosition < reusableBuffer.viewText.linesCount) {
        if (checklistPosition-(int)menuVerticalOffset < LCD_LINES-1) {
          ++checklistPosition;
          if (checklistPosition-(int)menuVerticalOffset >= LCD_LINES-2 && menuVerticalOffset+LCD_LINES-1 < reusableBuffer.viewText.linesCount) {
            ++menuVerticalOffset;
            sdReadTextFile(reusableBuffer.viewText.filename, reusableBuffer.viewText.lines, reusableBuffer.viewText.linesCount);
          }
        }
      }
      else {
        if (reusableBuffer.viewText.pushMenu == true) popMenu();
        reusableBuffer.viewText.checklistComplete = true;
      }
    }
  } else if (event == EVT_KEY_BREAK(KEY_EXIT)) {
    if (!g_model.checklistInteractive || reusableBuffer.viewText.pushMenu) {
      if (reusableBuffer.viewText.pushMenu == true) popMenu();
      reusableBuffer.viewText.checklistComplete = true;
    }
  }

  for (int i=0; i<LCD_LINES-1; i++) {
    if (g_model.checklistInteractive){
      if (reusableBuffer.viewText.lines[i][0] == CHECKABLE_PREFIX) {
        if (i < reusableBuffer.viewText.linesCount && !reusableBuffer.viewText.pushMenu)
          drawCheckBox(0, i*FH+FH+1, i < checklistPosition-(int)menuVerticalOffset, i == checklistPosition-(int)menuVerticalOffset);
        lcdDrawText(8, i*FH+FH+1, &reusableBuffer.viewText.lines[i][1], FIXEDWIDTH);
      }
      else {
        lcdDrawText(8, i*FH+FH+1, &reusableBuffer.viewText.lines[i][0], FIXEDWIDTH);
        if (i == checklistPosition-(int)menuVerticalOffset){
          ++checklistPosition;
          if (checklistPosition-(int)menuVerticalOffset == LCD_LINES-1 && menuVerticalOffset+LCD_LINES-1 < reusableBuffer.viewText.linesCount) {
            ++menuVerticalOffset;
            sdReadTextFile(reusableBuffer.viewText.filename, reusableBuffer.viewText.lines, reusableBuffer.viewText.linesCount);
            i = 0;  // Reset rendering of the display after changing the offest
          }
        }
      }
    }
    else {
      lcdDrawText(0, i*FH+FH+1, reusableBuffer.viewText.lines[i], FIXEDWIDTH);
    }
  }

  char * title = reusableBuffer.viewText.filename;
#if defined(SIMU)
  if (!strncmp(title, "./", 2)) title += 2;
#else
  // TODO?
#endif
  lcdDrawText(LCD_W/2, 0, getBasename(title), CENTERED);
  lcdInvertLine(0);

  if (reusableBuffer.viewText.linesCount > LCD_LINES-1) {
    drawVerticalScrollbar(LCD_W-1, FH, LCD_H-FH, menuVerticalOffset, reusableBuffer.viewText.linesCount, LCD_LINES-1);
  }
}

void pushMenuTextView(const char *filename)
{
  if (strlen(filename) < TEXT_FILENAME_MAXLEN) {
    strcpy(reusableBuffer.viewText.filename, filename);
    reusableBuffer.viewText.pushMenu = true;
    pushMenu(menuTextView);
  }
}