#define _INTERRUPT_C_

#include <asm/port_io.h>
#include <kernel/hw/keyboard.h>
#include <kernel/hw/timer.h>
#include <kernel/interrupt.h>
#include <kernel/mem.h>
#include <kernel/stdio.h>
#include <kernel/tty.h>
#include <kernel/vga.h>
#include <kernel_main.h>

static struct IDT_entry IDT[256];

void init_idt()
{
    asm_cli();

    memset(IDT, 0x00, sizeof(IDT));

    // invalid opcode
    SET_IDT_ENTRY_FN(6, int6, 0x08);
    // double fault
    SET_IDT_ENTRY_FN(8, int8, 0x08);
    // general protection
    SET_IDT_ENTRY_FN(13, int13, 0x08);
    // page fault
    SET_IDT_ENTRY_FN(14, int14, 0x08);

    uint16_t idt_descriptor[3];
    idt_descriptor[0] = sizeof(struct IDT_entry) * 256;
    *((uint32_t*)(idt_descriptor + 1)) = (ptr_t)IDT;

    asm_load_idt(idt_descriptor, 0);
}

void init_pic(void)
{
    asm_cli();

    asm_outb(PORT_PIC1_COMMAND, 0x11); // edge trigger mode
    asm_outb(PORT_PIC1_DATA, 0x20); // start from int 0x20
    asm_outb(PORT_PIC1_DATA, 0x04); // PIC1 is connected to IRQ2 (1 << 2)
    asm_outb(PORT_PIC1_DATA, 0x01); // no buffer mode

    asm_outb(PORT_PIC2_COMMAND, 0x11); // edge trigger mode
    asm_outb(PORT_PIC2_DATA, 0x28); // start from int 0x28
    asm_outb(PORT_PIC2_DATA, 0x02); // connected to IRQ2
    asm_outb(PORT_PIC2_DATA, 0x01); // no buffer mode

    // allow all the interrupts
    asm_outb(PORT_PIC1_DATA, 0x00);
    asm_outb(PORT_PIC2_DATA, 0x00);

    // 0x08 stands for kernel code segment
    SET_UP_IRQ(0, 0x08);
    SET_UP_IRQ(1, 0x08);
    SET_UP_IRQ(2, 0x08);
    SET_UP_IRQ(3, 0x08);
    SET_UP_IRQ(4, 0x08);
    SET_UP_IRQ(5, 0x08);
    SET_UP_IRQ(6, 0x08);
    SET_UP_IRQ(7, 0x08);
    SET_UP_IRQ(8, 0x08);
    SET_UP_IRQ(9, 0x08);
    SET_UP_IRQ(10, 0x08);
    SET_UP_IRQ(11, 0x08);
    SET_UP_IRQ(12, 0x08);
    SET_UP_IRQ(13, 0x08);
    SET_UP_IRQ(14, 0x08);
    SET_UP_IRQ(15, 0x08);

    asm_sti();
}

void int6_handler(
    struct regs_32 s_regs,
    uint32_t error_code,
    ptr_t eip,
    uint16_t cs)
{
    char buf[512];

    tty_print(console, "---- INVALID OPCODE ----\n");

    snprintf(
        buf, 512,
        "eax: %x, ebx: %x, ecx: %x, edx: %x\n"
        "esp: %x, ebp: %x, esi: %x, edi: %x\n"
        "eip: %x, cs: %x, error_code: %x   \n",
        s_regs.eax, s_regs.ebx, s_regs.ecx,
        s_regs.edx, s_regs.esp, s_regs.ebp,
        s_regs.esi, s_regs.edi, eip,
        cs, error_code);
    tty_print(console, buf);

    tty_print(console, "----   HALTING SYSTEM   ----");

    asm_cli();
    asm_hlt();
}

// general protection
void int13_handler(
    struct regs_32 s_regs,
    uint32_t error_code,
    ptr_t eip,
    uint16_t cs,
    uint32_t eflags)
{
    char buf[512];

    tty_print(console, "---- SEGMENTATION FAULT ----\n");

    snprintf(
        buf, 512,
        "eax: %x, ebx: %x, ecx: %x, edx: %x\n"
        "esp: %x, ebp: %x, esi: %x, edi: %x\n"
        "eip: %x, cs: %x, error_code: %x   \n"
        "eflags: %x                        \n",
        s_regs.eax, s_regs.ebx, s_regs.ecx,
        s_regs.edx, s_regs.esp, s_regs.ebp,
        s_regs.esi, s_regs.edi, eip,
        cs, error_code, eflags);
    tty_print(console, buf);

    tty_print(console, "----   HALTING SYSTEM   ----");

    asm_cli();
    asm_hlt();
}

static size_t page_fault_times;

// page fault
void int14_handler(
    linr_ptr_t l_addr,
    struct regs_32 s_regs,
    struct page_fault_error_code error_code,
    void* v_eip,
    uint16_t cs,
    uint32_t eflags)
{
    MAKE_BREAK_POINT();
    char buf[512];

    ++page_fault_times;

    // not present page, possibly mapped but not loaded
    // or invalid address or just invalid address
    // TODO: mmapping and swapping
    if (error_code.present == 0) {
        goto kill;
    }

    // kernel code
    if (cs == KERNEL_CODE_SEGMENT) {
        if (is_l_ptr_valid(kernel_mm_head, l_addr) != GB_OK) {
            goto kill;
        }
        struct page* page = find_page_by_l_ptr(kernel_mm_head, l_addr);

        // copy on write
        if (error_code.write == 1 && page->attr.cow == 1) {
            page_directory_entry* pde = kernel_mm_head->pd + linr_addr_to_pd_i(l_addr);
            page_table_entry* pte = p_ptr_to_v_ptr(page_to_phys_addr(pde->in.pt_page));
            pte += linr_addr_to_pt_i(l_addr);

            // if it is a dying page
            if (*page->ref_count == 1) {
                page->attr.cow = 0;
                pte->in.a = 0;
                pte->in.rw = 1;
                return;
            }
            // duplicate the page
            page_t new_page = alloc_raw_page();
            void* new_page_data = p_ptr_to_v_ptr(page_to_phys_addr(new_page));
            memcpy(new_page_data, p_ptr_to_v_ptr(page_to_phys_addr(page->phys_page_id)), PAGE_SIZE);

            pte->in.page = new_page;
            pte->in.rw = 1;
            pte->in.a = 0;

            --*page->ref_count;

            page->ref_count = (size_t*)k_malloc(sizeof(size_t));
            *page->ref_count = 1;
            page->attr.cow = 0;
            page->phys_page_id = new_page;
            return;
        }
    }

kill:
    snprintf(
        buf, 512,
        "killed: segmentation fault (eip: %x, cr2: %x, error_code: %x)", v_eip, l_addr, error_code);
    tty_print(console, buf);
    asm_cli();
    asm_hlt();
}

void irq0_handler(void)
{
    inc_tick();
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
// keyboard interrupt
void irq1_handler(void)
{
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
    handle_keyboard_interrupt();
}
void irq2_handler(void)
{
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq3_handler(void)
{
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq4_handler(void)
{
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq5_handler(void)
{
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq6_handler(void)
{
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq7_handler(void)
{
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq8_handler(void)
{
    asm_outb(PORT_PIC2_COMMAND, PIC_EOI);
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq9_handler(void)
{
    asm_outb(PORT_PIC2_COMMAND, PIC_EOI);
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq10_handler(void)
{
    asm_outb(PORT_PIC2_COMMAND, PIC_EOI);
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq11_handler(void)
{
    asm_outb(PORT_PIC2_COMMAND, PIC_EOI);
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq12_handler(void)
{
    asm_outb(PORT_PIC2_COMMAND, PIC_EOI);
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq13_handler(void)
{
    asm_outb(PORT_PIC2_COMMAND, PIC_EOI);
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq14_handler(void)
{
    asm_outb(PORT_PIC2_COMMAND, PIC_EOI);
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}
void irq15_handler(void)
{
    asm_outb(PORT_PIC2_COMMAND, PIC_EOI);
    asm_outb(PORT_PIC1_COMMAND, PIC_EOI);
}