/**
 * TODO file description
 */

#ifndef HD44780UTF_LCDBUF_H
#define HD44780UTF_LCDBUF_H

#include <stdint.h>
#include "utf8.h"
#include "cgram.h"
#include "cgrom.h"

#define LINE_NUM 4
#define LINE_LEN 20

#define BUFLEN_DIRTY_LIST 8

_Static_assert(LINE_NUM * LINE_LEN < 256, "LINE_NUM * LINE_LEN must fit in u8");

/** Indicates a range of screen cells that were changed and must be written to HW */
struct DirtyExtent {
  uint8_t row;
  uint8_t col;
  uint8_t count;
};

/** Struct for one CGRAM slot */
struct CgramState {
  /** UTF8 uint shown in this slot */
  uint32_t uint;
  /** Array index in the custom symbols table, use for look-up when writing the font data to HW */
  uint32_t symbol_index;
  /** Number of occurrences of this symbol in the screen array */
  uint8_t refcount;
  /** This CGRAM slot needs to be written to HW */
  bool dirty;
};

struct LcdBuffer {
  /** The raw screen buffer. Custom symbols are 0x00-0x07 */
  uint8_t screen[LINE_NUM][LINE_LEN];
  /** CGRAM state array */
  struct CgramState cgram[8];
  /** Hardware CGROM lookup table, used to map UTF8 to existing ROM symbols */
  const struct cgrom_entry *cgrom;
  /** Defined custom display pattern of utf8 symbols */
  const struct cgram_pattern *custom_symbols;

  /** Array of dirty extents - ranges in the display that need to be flushed to HW */
  struct DirtyExtent dirty_extents[BUFLEN_DIRTY_LIST];
  /** If the dirty extents array was not sufficient to hold all changes, this flag is set,
   * indicating the dirty_extents array should be disregarded. */
  bool full_repaint_required;
};

/** Initialize the struct */
void LcdBuffer_Init(struct LcdBuffer *self, const struct cgrom_entry *cgrom, const struct cgram_pattern *custom_symbols);

/** Clear the screen */
void LcdBuffer_Clear(struct LcdBuffer *self);

/** Write what needs to be written to the HW, clear all dirty marks */
void LcdBuffer_Flush(struct LcdBuffer *self);

/** Fully write everything to the display */
void LcdBuffer_FlushAll(struct LcdBuffer *self);

/** Set one utf8 character at a position */
void LcdBuffer_Set(struct LcdBuffer *self, uint8_t row, uint8_t col, struct Utf8Char ch);

/** Write a UTF8 string at a position */
void LcdBuffer_Write(struct LcdBuffer *self, uint8_t row, uint8_t col, char *utf_string);

/* Callbacks - need to be implemented by the application! */

/** Write character data at position */
void LcdBuffer_IO_WriteAt(uint8_t row, uint8_t col, const uint8_t *buf, uint8_t len);

/** Write CGRAM data. Data is always 8 bytes long. */
void LcdBuffer_IO_WriteCGRAM(uint8_t position, const uint8_t* data);

#endif //HD44780UTF_LCDBUF_H