//
// Created by Stepan Usatiuk on 02.03.2025.
//

#ifndef CB_DISPLAY_HPP
#define CB_DISPLAY_HPP

#include "config.hpp"

#include "driver/spi_master.h"
// (Async memcpy removed for debugging simplification)

#include <array>
#include <bitset>


namespace SMD {
static constexpr size_t kLineBytes       = DISP_WIDTH / 8;
static constexpr size_t kLineMultiSingle = (kLineBytes + 2);
static constexpr size_t kLineDataBytes   = kLineMultiSingle * DISP_HEIGHT + 2;

extern uint8_t* dma_buf;

void init();
// Double-buffered asynchronous frame pipeline:
// Usage pattern each frame:
//   SMD::frame_ready();  // (start of frame) waits for previous transfer & ensures draw buffer is ready/synced
//   ... write pixels into dma_buf via set_pixel / surface ...
//   SMD::send_frame();  // (end of frame) queues SPI DMA of current framebuffer; once SPI finishes the sent buffer
//                       // is optionally cleared so the alternate buffer is ready for the next frame
void send_frame(bool clear_after_send = true);
void frame_ready();
bool frame_transfer_in_flight(); // optional diagnostic: is a frame transfer still in flight?

__attribute__((always_inline)) static void set_pixel(int x, int y, bool value) {
    assert(x >= 0 && x < DISP_WIDTH && y >= 0 && y < DISP_HEIGHT);

    unsigned lineIdx = 2 + kLineMultiSingle * y + (x / 8);
    unsigned bitIdx  = 1 << (7 - (x % 8)) % 8;

    if (value) {
        dma_buf[lineIdx] &= ~bitIdx;
    } else {
        dma_buf[lineIdx] |= bitIdx;
    }
}

extern "C" void s_spi_post_cb(spi_transaction_t* trans);

static inline spi_device_interface_config_t _devcfg = {
        .mode           = 0,                // SPI mode 0
        .clock_speed_hz = 10 * 1000 * 1000, // Clock out at 10 MHz
        .spics_io_num   = SPI_DISP_CS,      // CS pin
        .flags          = SPI_DEVICE_POSITIVE_CS,
        .queue_size     = 1,
        .pre_cb         = nullptr,
        .post_cb        = s_spi_post_cb,
};
extern spi_device_handle_t _spi;
}; // namespace SMD

#endif // DISPLAY_HPP