#ifndef _ESPRESSO_SYSCALL_H
#define _ESPRESSO_SYSCALL_H

#include <drivers/idt.h>

#define SYSCALL_INT 0x30

enum {
  SYS_MAP_PAGE = 0, /* void map_page(void* phys_addr, void* virt_addr); */
  SYS_PMM_ALLOC_PAGE, /* void* pmm_alloc_page(void); */
  SYS_PMM_FREE_PAGE, /* void  pmm_free_page(void* addr); */
  SYS_SERIAL_WRITE, /* void serial_write(char a); */
  SYS_SERIAL_READ, /* char serial_read(void); */
  SYS_SERIAL_PUTS, /* void serial_puts(const char* s); */
  SYS_USE_SERIAL, /* bool use_serial(void); */
  SYS_TERMINAL_SCROLL, /* void terminal_scroll(void); */
  SYS_TERMINAL_CLEAR, /* void terminal_clear(void); */
  SYS_TERMINAL_SET_CURSOR, /* void terminal_set_cursor(uint16_t row, uint16_t column); */
  SYS_TERMINAL_GET_CURSOR, /* void terminal_get_cursor(int* row, int* column); */
  SYS_TERMINAL_WRITE, /* void terminal_write(const char* data, size_t size); */
  SYS_TERMINAL_WRITESTRING, /* void terminal_writestring(const char* data) */
  SYS_TERMINAL_DEBUG_WRITESTRING, /* void terminal_debug_writestring(const char* data); */
  SYS_TERMINAL_PUTCHAR, /* void terminal_putchar(char c); */
  SYS_TERMINAL_PUTENTRYAT, /* void terminal_putentryat(unsigned char c, uint8_t color, size_t x, size_t y); */
  SYS_TERMINAL_GETCOLOR, /* uint8_t terminal_getcolor(void); */
  SYS_TERMINAL_SETCOLOR, /* void terminal_setcolor(uint8_t color); */
  SYS_READ, /* int read(uint32_t fd, void* data, size_t max_len); */
  SYS_WRITE, /* int write(uint32_t fd, void* data, size_t len); */
  __ENUM_END_MARKER__,
};


#define syscall0(num) ({ \
    int ret; \
    asm volatile ( \
        "int %1" \
        : "=a"(ret) \
        : "i"(SYSCALL_INT), "a"(num) \
        : "memory" \
    ); \
    ret; \
})

/* syscall 1 */
#define syscall1(num, a) ({ \
    int ret; \
    asm volatile ( \
        "int %1" \
        : "=a"(ret) \
        : "i"(SYSCALL_INT), "a"(num), "b"(a) \
        : "memory" \
    ); \
    ret; \
})

#define syscall2(num, a, b) ({ \
    int ret; \
    asm volatile ( \
        "int %1" \
        : "=a"(ret) \
        : "i"(SYSCALL_INT), "a"(num), "b"(a), "c"(b) \
        : "memory" \
    ); \
    ret; \
})

#define syscall3(num, a, b, c) ({ \
    int ret; \
    asm volatile ( \
        "int %1" \
        : "=a"(ret) \
        : "i"(SYSCALL_INT), "a"(num), "b"(a), "c"(b), "d"(c) \
        : "memory" \
    ); \
    ret; \
})

#define syscall4(num, a, b, c, d) ({ \
    int ret; \
    asm volatile ( \
        "int %1" \
        : "=a"(ret) \
        : "i"(SYSCALL_INT), "a"(num), "b"(a), "c"(b), "d"(c), "S"(d) \
        : "memory" \
    ); \
    ret; \
})

#define syscall5(num, a, b, c, d, e) ({ \
    int ret; \
    asm volatile ( \
        "int %1" \
        : "=a"(ret) \
        : "i"(SYSCALL_INT), "a"(num), "b"(a), "c"(b), "d"(c), "S"(d), "D"(e) \
        : "memory" \
    ); \
    ret; \
})

/* some macros for commonly used functions */
#define syscall_terminal_writestring(ptr) syscall1(SYS_TERMINAL_WRITESTRING, ptr);
#define syscall_terminal_putchar(chr) syscall1(SYS_TERMINAL_PUTCHAR, chr);
#define syscall_map_page(phys, virt) syscall2(SYS_MAP_PAGE, phys, virt);
#define syscall_pmm_alloc_page() syscall0(SYS_PMM_ALLOC_PAGE);
#define syscall_pmm_free_page(addr) syscall1(SYS_PMM_FREE_PAGE, addr);

void init_sysints(void);

registers_t* int16_handler(registers_t* regs);

#endif