/**
 * Copyright (c) 2022 Dominic Masters
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include "textbox.h"

char TEXTBOX_TEXTS[TEXTBOX_SCROLL_ROWS_MAX * TEXTBOX_CHARS_PER_ROW];
uint8_t TEXTBOX_ROW_COUNT;
uint8_t TEXTBOX_ROW_TILE_LAST;
uint8_t TEXTBOX_ROW_CURRENT;
uint8_t TEXTBOX_STATE;
uint8_t TEXTBOX_SCROLL;

inline void conversationTextboxInit() {
  // Reset textbox state
  TEXTBOX_STATE = 0;
}

void conversationTextboxSetText(char *text) {
  uint8_t i, j, k, rowStart, stateFlags;
  char c, c2;

  // Begin by filling the textbox text chars with whitespace to begin.
  // TODO: I'm pretty sure I can move this lower and optimize.
  for(i = 0; i < TEXTBOX_SCROLL_ROWS_MAX * TEXTBOX_CHARS_PER_ROW; i++) {
    TEXTBOX_TEXTS[i] = ' ';
  }
  
  // Reset textbox state
  TEXTBOX_STATE = TEXTBOX_STATE_VISIBLE;
  TEXTBOX_SCROLL = 0;
  TEXTBOX_ROW_COUNT = 0;
  TEXTBOX_ROW_COUNT = 1;
  
  // Copy source text to buffer, also determine wordwrapping here.
  i = 0, j = 0, rowStart = 0, stateFlags = 0;
  while((c = text[i]) != '\0') {// "For each char in string"
    if(c == ' ') {
      // Scan ahead and look at how many chars remain to the next space.
      k = i + 1;
      while(
        (c2 = text[k]) != '\0' &&
        c2 != '\n' &&
        c2 != ' ' &&
        (k - rowStart) < TEXTBOX_CHARS_PER_ROW
      ) k++;
      
      // IF that number is less than the remaining chars on the current row,
      // then treat this space like a newline.
      if(k >= (rowStart + TEXTBOX_CHARS_PER_ROW + 1)) {
        stateFlags |= 1 << 0;
      }
    } else if(c == '\n') {
      stateFlags |= 1 << 0;
    }

    // Do we need to insert newline where we are currently?
    if((stateFlags & (1 << 0)) != 0) {
      stateFlags &= ~(1 << 0);// Remove newline flag
      i++;
      rowStart = i;// Update the row start (Should this be i+1?)
      //TODO: can I optimize the next line by using rowStart somehow?
      j = ((j / TEXTBOX_CHARS_PER_ROW)+1) * TEXTBOX_CHARS_PER_ROW;// Update destination character position.
      TEXTBOX_ROW_COUNT++;
      continue;
    }

    // Insert the character
    TEXTBOX_TEXTS[j] = c;
    i++;
    j++;
  }

  // Now we have organized the string nicely we can prep for rendering. Fill the
  // tiles with blank chars.
  textboxFillBlank();
  WY_REG = TEXTBOX_WINDOW_Y * TILE_HEIGHT;
  SHOW_WIN;
}

inline void textboxFillBlank() {
  uint8_t tiles[TEXTBOX_WIDTH_IN_TILES * TEXTBOX_HEIGHT_IN_TILES];

  spriteBorderBufferEdges(
    tiles, TEXTBOX_WIDTH_IN_TILES, TEXTBOX_HEIGHT_IN_TILES, SPRITE_TILESET_WHITE_HIGH
  );

  spriteBufferWindow(
    0x00, TEXTBOX_Y,
    TEXTBOX_WIDTH_IN_TILES, TEXTBOX_HEIGHT_IN_TILES,
    tiles
  );
}

inline void conversationTextboxUpdate() {
  uint8_t i, tile;
  char c;

  // Is the textbox visible?
  if((TEXTBOX_STATE & TEXTBOX_STATE_VISIBLE) == 0) return;

  // Have we finished scrolling?
  if(TEXTBOX_STATE & TEXTBOX_STATE_SCROLLED) {
    // Is the user trying to go to the next line?
    if(INPUT_PRESSED & J_A) {
      // First, lets figure out if there's any more text to reveal or not.
      if((TEXTBOX_ROW_COUNT - TEXTBOX_ROW_CURRENT) < TEXTBOX_TILES_ROWS) {
        TEXTBOX_STATE &= ~TEXTBOX_STATE_VISIBLE;
        HIDE_WIN;
        LCDC_REG |= LCDCF_BG8000;
        conversationQueueNext();
        return;
      }

      TEXTBOX_STATE &= ~TEXTBOX_STATE_SCROLLED;
      TEXTBOX_SCROLL = 0;
      TEXTBOX_ROW_CURRENT += TEXTBOX_TILES_ROWS;
      textboxFillBlank();
    }
    return;
  }

  // Move to the next character.
  i = TEXTBOX_ROW_CURRENT * TEXTBOX_CHARS_PER_ROW;
  c = TEXTBOX_TEXTS[i+TEXTBOX_SCROLL];

  if(TEXTBOX_SCROLL == TEXTBOX_CHARS_MAX) {
    TEXTBOX_STATE |= TEXTBOX_STATE_SCROLLED;
  } else {
    tile = spriteFontTileFromChar(c);

    spriteBufferWindow(
      0x01 + (TEXTBOX_SCROLL % TEXTBOX_CHARS_PER_ROW),
      TEXTBOX_Y + 0x01 + (TEXTBOX_SCROLL / TEXTBOX_CHARS_PER_ROW),
      1, 1,
      &tile
    );

    TEXTBOX_SCROLL++;
    
    // Skip spaces
    while(TEXTBOX_SCROLL < TEXTBOX_CHARS_MAX && TEXTBOX_TEXTS[i+TEXTBOX_SCROLL] == ' ') TEXTBOX_SCROLL++;
  }
}