#include "include/interrupts.h"
#include "datatypes.h"
#include "packing.h"
#include "include/screen.h"
#include "include/pic_8259.h"

OS_PACK_START
typedef struct __idt_attributes {
	os_u8 gate_type: 4;
	os_u8 empty : 1;
	os_u8 dpl : 2;
	os_u8 present: 1;
} OS_PACK_MID idt_attributes;
OS_PACK_END

#define IDT_GATE_TYPE_TASK			0x5
#define IDT_GATE_TYPE_INTERRUPT_16	0x6
#define IDT_GATE_TYPE_TRAP_16		0x7
#define IDT_GATE_TYPE_INTERRUPT_32	0xE
#define IDT_GATE_TYPE_TRAP_32		0xF

OS_PACK_START
typedef struct __idt_entry {
	os_u16 isr_low;
	os_u16 kernel_gdt_code_segment;
	os_u8 reserved;
	idt_attributes attributes;
	//os_u8 attributes;
	os_u16 isr_high;
} OS_PACK_MID idt_entry;
OS_PACK_END

OS_PACK_START
typedef struct __idt_ptr {
	os_u16 limit;
	os_u32 base;
} OS_PACK_MID idt_ptr;
OS_PACK_END


#define EFFECTIVE_INTERRUPT_AMOUNT 256

__attribute__((aligned(0x10)))
idt_entry main_idt[EFFECTIVE_INTERRUPT_AMOUNT];
idt_ptr main_idt_ptr;
volatile void* interrupt_service_list[EFFECTIVE_INTERRUPT_AMOUNT];

os_u64 os_ticks = 0;

os_u32 target_waiting_interrupt = 0;
os_u32 target_waiting_flag = 0;

void os_interrupt_signal(os_u32 interrupt_id) {
	if (target_waiting_interrupt == interrupt_id && target_waiting_flag != 0) {
		target_waiting_flag = 0;
		target_waiting_interrupt = 0;
	}
}

void generic_exception(os_u32 interrupt_id) {
	//screen_clear();
	screen_set_pos(0, 0);
	screen_write_error("Exception received: ", 0);
	screen_write_number_error(interrupt_id);
	screen_write_string("\n", 0);
	while(1) {

	}
}

void handle_irq0(os_u32 interrupt_id) {
	os_ticks++;

	pic_sendEOI(0);
}

void handle_irq1(os_u32 interrupt_id) {
	os_interrupt_signal(interrupt_id);

	pic_sendEOI(1);
}

void handle_double_fault(os_u32 interrupt_id) {
	screen_set_pos(0, 0);
	screen_write_error("Double fault.\n", 0);
	while(1) {

	}
}

/* The following is defined in interrupt_utils.asm */
extern void* interrupt_service_table[];
extern void load_idt();
/* --- */

void setup_interrupts() {

	main_idt_ptr.base = (os_u32) &main_idt[0];
	main_idt_ptr.limit = ((os_u16) (sizeof(idt_entry) * EFFECTIVE_INTERRUPT_AMOUNT)) - 1;
	for (int i = 0; i < EFFECTIVE_INTERRUPT_AMOUNT; i++) {

		os_u32 val = (os_u32) interrupt_service_table[i];
		//os_u32 val = (os_u32) &generic_exception;
		main_idt[i].isr_low = (os_u16)(val & 0xFFFF);
		main_idt[i].isr_high = (os_u16)(val >> 16);
		main_idt[i].kernel_gdt_code_segment = 0x08;
		main_idt[i].reserved = 0;

		main_idt[i].attributes.present = 1;
		main_idt[i].attributes.gate_type = IDT_GATE_TYPE_INTERRUPT_32;
		main_idt[i].attributes.empty = 0;
		main_idt[i].attributes.dpl = i == 0x49 ? 3 : 0;

		interrupt_service_list[i] = (void*)&generic_exception;
	}

	main_idt[3].attributes.gate_type = IDT_GATE_TYPE_TRAP_32;
	main_idt[4].attributes.gate_type = IDT_GATE_TYPE_TRAP_32;

	interrupt_service_list[8] = (void*)&handle_double_fault;
	interrupt_service_list[32] = (void*)&handle_irq0;
	interrupt_service_list[33] = (void*)&handle_irq1;


	load_idt();
}

os_bool os_interrupt_wait(os_u32 interrupt, os_u64 timeout) {
	if (interrupt != 33) //Keyboard interrupt
		return OS_FALSE;

	if (target_waiting_interrupt != 0 || target_waiting_flag != (os_u32*)0) {
		return OS_FALSE;
	}

	os_u64 start_ticks = os_ticks;
	target_waiting_interrupt = interrupt;
	target_waiting_flag = 1;
	while(target_waiting_flag) {
		if(timeout != 0 && (os_ticks - start_ticks) >= timeout) {
			target_waiting_flag = 0;
			target_waiting_interrupt = 0;
			return OS_FALSE;
		}
	}

	return OS_TRUE;
}