#ifndef NOVA64_CORE_H
#define NOVA64_CORE_H

#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>


// Cross-platform DLL export/import visibility macros
#if defined(_WIN32) || defined(__CYGWIN__)
#ifdef NOVA64_EXPORTS
#define NOVA64_API __declspec(dllexport)
#else
#define NOVA64_API __declspec(dllimport)
#endif
#else
#if __GNUC__ >= 4
#define NOVA64_API __attribute__((visibility("default")))
#else
#define NOVA64_API
#endif
#endif

/* ========================================================================== */
/* I/O Callback Typedefs                                                      */
/* ========================================================================== */

/**
 * @brief Callback to flush a frame buffer to the display.
 * @param buffer Pointer to raw pixel data (e.g., RGB565 / RGBA8888).
 * @param width Frame width in pixels.
 * @param height Frame height in pixels.
 */
typedef void (*nova64_display_flush_cb_t)(const uint16_t *buffer,
                                          uint16_t width, uint16_t height);

/**
 * @brief Callback to output audio samples.
 * @param samples Pointer to PCM audio sample buffer.
 * @param count Number of samples in the buffer.
 */
typedef void (*nova64_audio_output_cb_t)(const int16_t *samples,
                                         uint32_t count);

/**
 * @brief Callback to read data from the SD card.
 * @param slot_idx Zero-based cartridge slot index.
 * @param file_path Null-terminated path to the file to read.
 * @param destination_buffer Pointer to memory where file data should be copied.
 * @param destination_length Maximum number of bytes available in the
 * destination buffer.
 * @return Number of bytes read on success, negative value on read error.
 */
typedef int32_t (*nova64_sd_read_file_cb_t)(uint32_t slot_idx,
                                            const char *file_path,
                                            uint8_t *destination_buffer,
                                            uint32_t destination_length);

/**
 * @brief Callback to retrieve the size of a file on the SD card.
 * @param slot_idx Zero-based cartridge slot index.
 * @param file_path Null-terminated path to the file.
 * @return File size in bytes on success, negative value on error.
 */
typedef int32_t (*nova64_sd_get_file_size_cb_t)(uint32_t slot_idx,
                                                 const char *file_path);

/**
 * @brief Callback triggered when a cartridge state change occurs (e.g.
 * inserted/removed).
 * @param slot_idx Zero-based cartridge slot index.
 * @param is_inserted True if a cartridge is detected, false if ejected.
 */
typedef void (*nova64_cartridge_status_cb_t)(uint32_t slot_idx,
                                             bool is_inserted);

/**
 * @brief Callback for core log output.
 * @param message Null-terminated UTF-8 log string.
 */
typedef void (*nova64_log_cb_t)(const char *message);

/* ========================================================================== */
/* I/O Interface Configuration Struct                                         */
/* ========================================================================== */

/**
 * @brief Struct containing all I/O hardware abstraction callbacks.
 *        Pass NULL for any unneeded callback.
 */
typedef struct {
  nova64_display_flush_cb_t display_flush;
  nova64_audio_output_cb_t audio_output;
  nova64_sd_read_file_cb_t sd_read_file;
  nova64_sd_get_file_size_cb_t sd_get_file_size;
  nova64_cartridge_status_cb_t cartridge_status;
  nova64_log_cb_t log_message;
} nova64_io_interface_t;

/* ========================================================================== */
/* Engine Core API                                                            */
/* ========================================================================== */

/**
 * @brief Initializes the core engine, registers host I/O interface callbacks,
 * and starts the built-in launcher from internal storage in the WASM runtime.
 * @param io_interface Pointer to filled struct containing I/O function
 * pointers.
 * @return True if initialized successfully, false if already initialized or
 * invalid.
 */
NOVA64_API bool nova64_init(const nova64_io_interface_t *io_interface);

/**
 * @brief Starts the main engine runtime and launches the FreeRTOS scheduler.
 * @return 0 on success, negative error code on failure.
 */
NOVA64_API int32_t nova64_main();

#if defined(NOVA64_SHUTDOWN_AVAILABLE)
/**
 * @brief Requests shutdown of the FreeRTOS scheduler.
 * @return True if the shutdown request was issued, false otherwise.
 */
NOVA64_API bool nova64_shutdown(void);
#endif

/**
 * @brief Retrieves the engine version integer.
 * @return 24-bit packed version number (0xMMmmPP -> Major, Minor, Patch).
 */
NOVA64_API uint32_t nova64_get_version(void);

#endif // NOVA64_CORE_H