//
// http://www.jamesmolloy.co.uk/tutorial_html/9.-Multitasking.html
//

#include "kernel.h"	// general kernel config & includes
#include "console.h"	// this will allow us to write to screen
#include "x86.h"

#include "../lib/logger/log.h"	// logger facilities
#define FOOLOS_MODULE_NAME "kernel"

// TODO: cleanup . WHHYY can i compile it without the includes!??

///////
// interrupt handler prototypes
// todo: move somewhere else!?
void int_def_handler();
void int_clock_handler();
void int_kb_handler();
void int_floppy_handler();

////////// KERNEL MAIN///// /////
//

uint32_t read_eip();


void int_irq0(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Divide by 0");   X86_IRQ_END }
void int_irq1(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Single step (debugger)");   X86_IRQ_END }
void int_irq2(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Non Maskable Interrupt");   X86_IRQ_END }
void int_irq3(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Breakpoint (debugger)");   X86_IRQ_END }
void int_irq4(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Overflow");   X86_IRQ_END }
void int_irq5(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Bounds check");   X86_IRQ_END }
void int_irq6(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Undefined OP Code");   X86_IRQ_END }
void int_irq7(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"No coprocessor");   X86_IRQ_END }
void int_irq8(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Double Fault");   X86_IRQ_END }
void int_irq9(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Coprocessor Segment Overrun");   X86_IRQ_END }
void int_irq10(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Invalid TSS");   X86_IRQ_END }
void int_irq11(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Segment Not Present");   X86_IRQ_END }
void int_irq12(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Stack Segment Overrun");   X86_IRQ_END }

void show_error(uint32_t err)
{
   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"interrupt error code:  0x%08x",err);
   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"External Event: %x",err&0b001);
   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"Location: %x",err&0b110);
   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"Selector: %x",err&0b1111111111111000);
}

void int_irq13()
{
    X86_IRQ_BEGIN  
     
    uint32_t err;
    asm("pop %eax");  // get Error Code
    asm ("mov %%eax, %0":"=r"(err));
    show_error(err);

    panic(FOOLOS_MODULE_NAME,"General Protection Fault");   

    X86_IRQ_END 
}

void int_irq14(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Page Fault");   X86_IRQ_END }
void int_irq15(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Unassigned");   X86_IRQ_END }
void int_irq16(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Coprocessor error");   X86_IRQ_END }
void int_irq17(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Alignment Check");   X86_IRQ_END }
void int_irq18(){ X86_IRQ_BEGIN  panic(FOOLOS_MODULE_NAME,"Machine Check");   X86_IRQ_END }

void enable_a20()
{
//;    ;enable A20
//;    ;http://www.brokenthorn.com/Resources/OSDev9.html
//;    ;Method 3.1: Enables A20 through keyboard controller
//;    ;Not all keyboard controllers support this
     asm("mov $0xdd, %al");//	; command 0xdd: enable a20
//;   ;mov al, 0xdf	; command 0xdf: disable a20
     asm("outb %al, $0x64");//	; send command to controller
}

// heart of our operating system.
void kernel_main(uint32_t initial_stack)
{

    // 
    // We want to get output to the screen as fast as possible!
    //
    // Our Fool-Boot-Loader did set up VESA already for us.
    // The desired VESA mode is hardcoded in [boot/mbr.asm].
    //
    // The [vesa_init(...)] function requires:
    //
    //	* the addresses of the vbeinfo struct
    //	* the address of the vbemodeinfo struct (for selected mode).
    //	* the address of our Fool-Font binary data.
    //
    //	The first two paramters are hardcoded in [boot/mbr.asm],
    //	while the last one is set in the Makefile. The font binary
    //	is integrated in the kernel image.
    //
    //  this function returns the physical base address of 
    //  our video memory 
    //
    uint32_t vesa_physbase=vesa_init(0x8300,0x8400,0x7200);

    // initial stack
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"initial esp: 0x%08X",initial_stack);

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"enable A20");
    enable_a20();

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"setup PIC");
    pic_setup();

    // PIT config (timer)
    timer_init();

    // we know that here, the bootloader placed the mamory map!
    mem_init(0x7c00+0x400,*((uint16_t *)(0x7c00+0x600)));
    
    // paging  (pass the vesa physbase address for identity mapping)
    vmem_init(vesa_physbase);

    //

    // init and interrupt decriptor table 
    int_init(0x08);

    int_install();

    // setup custom interrupts
    // remember that we shifted all interrupts with the pic by 32
    // so clock = 32 (irq 0)
    // keyboard = 33 (irq 1)
    // floppy = 38 (irq 6)
    // etc..

    // install PIT interrupt handler
    int_install_ir(32, 0b10001110, 0x08,&int_clock_handler);

    // install keyboard interrupt handler
    int_install_ir(33, 0b10001110, 0x08,&int_kb_handler);

    // install floppy interrupt handler
    int_install_ir(38, 0b10001110, 0x08,&int_floppy_handler);

    
    // exceptions
    int_install_ir(0, 0b10001110, 0x08,&int_irq0);
    int_install_ir(1, 0b10001110, 0x08,&int_irq1);
    int_install_ir(2, 0b10001110, 0x08,&int_irq2);
    int_install_ir(3, 0b10001110, 0x08,&int_irq3);
    int_install_ir(4, 0b10001110, 0x08,&int_irq4);
    int_install_ir(5, 0b10001110, 0x08,&int_irq5);
    int_install_ir(6, 0b10001110, 0x08,&int_irq6);
    int_install_ir(7, 0b10001110, 0x08,&int_irq7);
    int_install_ir(8, 0b10001110, 0x08,&int_irq8);
    int_install_ir(9, 0b10001110, 0x08,&int_irq9);
    int_install_ir(10, 0b10001110, 0x08,&int_irq10);
    int_install_ir(11, 0b10001110, 0x08,&int_irq11);
    int_install_ir(12, 0b10001110, 0x08,&int_irq12);
    int_install_ir(13, 0b10001110, 0x08,&int_irq13);
    int_install_ir(14, 0b10001110, 0x08,&int_irq14);
    int_install_ir(15, 0b10001110, 0x08,&int_irq15);
    int_install_ir(16, 0b10001110, 0x08,&int_irq16);
    int_install_ir(17, 0b10001110, 0x08,&int_irq17);
    int_install_ir(18, 0b10001110, 0x08,&int_irq18);

    // now we can enable interrupts back again
    int_enable();

//    int x=10/0;

    // pci
    pci_init();

    // floppy
    // floppy_init();

    //init shell
    shell_init();

    // multitasking
    task_init();

    /*

   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"test mem");

   // test a20 disabled / wrap
   uint8_t *memtest=0x0;
   uint8_t *memtest2=0b10000000000000000000;

   *memtest=0xaf;
   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"test mem %x",*(memtest2-1));
   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"test mem %x",*memtest2);
   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"test mem %x",*(memtest2+1));
   */

    /* stack pointer test?
   uint32_t *esp=0x90000;
   for(int i=0;i<10;i++)
   {
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"esp: %x",*esp);
    esp--;
   }
   */
    while(1)
    {
	
    }

 
}