#include "kernel/kernel.h"
#include "asm/int.h"
#include "asm/pit.h"
#include "driver/mouse.h"
#include "interrupts.h"
#include "asm/x86.h"

/** The size of our interrupts table  */
#define INT_MAX 255 

/** The interrupt descriptor table */
static struct int_desc
{
    uint16_t addrLo;
    uint16_t sel;
    uint8_t zeros;
    uint8_t flags;
    uint16_t addrHi;
} idt[INT_MAX];

/** The interrupt descriptor table descriptor */
static struct idt_desc
{
    uint16_t size;
    uint16_t baseLo;
    uint16_t baseHi;
} idtd;

/** Sets a handler for a specific interrupt */
static void int_install_ir(int irq, uint16_t flags, uint16_t sel, void *addr)
{
   uint64_t base=(uint32_t)&(*(uint32_t*)addr);

    idt[irq].addrLo = base & 0xffff;
    idt[irq].addrHi = (base >> 16) & 0xffff;
    idt[irq].zeros=0;
    idt[irq].flags=flags;
    idt[irq].sel=sel;
}

/** Installs the interrupt table */
void int_install()
{
    idtd.size=sizeof(struct int_desc)*INT_MAX;
    uint32_t addr=(uint32_t)&idt[0];
    idtd.baseHi=addr>>16;
    idtd.baseLo=0xffff&addr;
    __asm__("lidt %0"::"m" (idtd));
}

/*
 * Interrupt dispatcher 
 *
 * Remeber that we are inside an interrupt here!
 *
 */

uint32_t interrupt_handler(uint32_t esp, uint32_t irq)
{
    if(irq==0)asm_pit_tick();  

    // mouse and kb
    if(irq==1 || irq==12 ){
	uint32_t in=x86_inb(0x60);
	if(irq=1)keyboard_handle(in); // do this in separate thread!
//	klog("0x60 in %d",in);
    }

    // 0x80 - a syscall is coming in
    if(irq==128){

	uint32_t *stack=esp;
	uint32_t eax=stack[11];
	uint32_t ebx=stack[8];
	uint32_t ecx=stack[10];
	uint32_t edx=stack[9];

//	klog("syscall: %d (ebx=0x%08X,ecx=0x%08X,edx=0x%08X)",eax,ebx,ecx,edx);

	task_syscall(eax,ebx,ecx,edx);
	esp=my_scheduler(esp,2); // force scheduling of pid=2 (kernel worker)
    }

    if(irq==0 || irq==129)esp=my_scheduler(esp,-1); // autoschedule

    if(irq==255)kpanic("Unhandled Interrupt!");

    return esp;
}

// log helpers //
void errlog(uint32_t error_code)
{
    klog("error_code: 0x%08X",error_code);
}

void defklog(uint32_t eip, uint16_t cs, uint32_t flags)
{
    klog("eip: 0x%08X",eip);
    klog("segment: 0x%08X",cs);
    klog("eflags: 0x%08X",flags);
}

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

//

void int_default()
{
   klog("default handler");
   kpanic("unhandled interrupt (is this a panic or should just iognore?)");
}

void exception_handle_0(){   kpanic("Divide by 0");    }
void exception_handle_1(){   kpanic("Single step (debugger)");    }
void exception_handle_2(){   kpanic("Non Maskable Interrupt");    }
void exception_handle_3(){   kpanic("Breakpoint (debugger)");    }
void exception_handle_4(){   kpanic("Overflow");    }
void exception_handle_5(){   kpanic("Bounds check");    }
void exception_handle_6(){   kpanic("Undefined OP Code");    }
void exception_handle_7(){   kpanic("No coprocessor");    }
void exception_handle_8(){   kpanic("Double Fault");    }
void exception_handle_9(){   kpanic("Coprocessor Segment Overrun");    }
void exception_handle_10(){   kpanic("Invalid TSS");    }
void exception_handle_11(){   kpanic("Segment Not Present");    }
void exception_handle_12(){   kpanic("Stack Segment Overrun");    }

void exception_handle_13(uint32_t error_code,uint32_t eip,uint16_t cs,uint16_t unused, uint32_t flags)
{
    errlog(error_code);
    defklog(eip,cs,flags);

    kpanic("Exception: Fault: General Protection Fault");   
}

void exception_handle_14(uint32_t error_code,uint32_t eip,uint16_t cs,uint16_t unused, uint32_t flags)
{
   errlog(error_code);
   klog("error_code_P: %d",error_code&1?1:0);
   klog("error_code_W/R: %d",error_code&2?1:0);
   klog("error_code_U/S: %d",error_code&4?1:0);
   klog("error_code_RSVD: %d",error_code&8?1:0);
   klog("error_code_I/D: %d",error_code&16?1:0);
   klog("at addr: 0x%08X",x86_get_cr(2));
   defklog(eip,cs,flags);
   kpanic("Exception: Fault: Page Fault");
}

void exception_handle_15(){   kpanic("Unassigned");    }
void exception_handle_16(){   kpanic("Coprocessor error");    }
void exception_handle_17(){   kpanic("Alignment Check");    }
void exception_handle_18(){   kpanic("Machine Check");    }

// set default handler for all interrupts for a start
void interrupts_init(uint16_t sel)
{
    //  Setup PIC
    klog("setting up PIC",&idt,&idtd);
    asm_pic_setup();

    klog("initializing. IDT: 0x%08x, IDTD: 0x%08X",&idt,&idtd);

    // Default interrupt handling
    for(int i=0; i<INT_MAX; i++)
    {
	int_install_ir(i, 0b10001110, sel,&int255);
    }

    // Exceptions
    int_install_ir(0,  0b10001110, 0x08,&exc0);
    int_install_ir(1,  0b10001110, 0x08,&exc1);
    int_install_ir(2,  0b10001110, 0x08,&exc2);
    int_install_ir(3,  0b10001110, 0x08,&exc3);
    int_install_ir(4,  0b10001110, 0x08,&exc4);
    int_install_ir(5,  0b10001110, 0x08,&exc5);
    int_install_ir(6,  0b10001110, 0x08,&exc6);
    int_install_ir(7,  0b10001110, 0x08,&exc7);
    int_install_ir(8,  0b10001110, 0x08,&exc8);
    int_install_ir(9,  0b10001110, 0x08,&exc9);
    int_install_ir(10, 0b10001110, 0x08,&exc10);
    int_install_ir(11, 0b10001110, 0x08,&exc11);
    int_install_ir(12, 0b10001110, 0x08,&exc12);
    int_install_ir(13, 0b10001110, 0x08,&exc13);
    int_install_ir(14, 0b10001110, 0x08,&exc14);
    int_install_ir(15, 0b10001110, 0x08,&exc15);
    int_install_ir(16, 0b10001110, 0x08,&exc16);
    int_install_ir(17, 0b10001110, 0x08,&exc17);
    int_install_ir(18, 0b10001110, 0x08,&exc18);
    

    // Custom interrupts (hardcoded)
    // remember that we shifted all interrupts with the pic by 32

    // PIT interrupt handler (irq 0 => 32)
    int_install_ir(32,   0b10001110, 0x08,&int0);

    // Keyboard interrupt handler (irq 1 => 33)
    int_install_ir(33,   0b10001110, 0x08,&int1);

    // Mouse  interrupt handler (irq 12 => 34)
    int_install_ir(44,   0b10001110, 0x08,&int12);

    // System Calls / they can be called from ring3 (0b11)
    int_install_ir(0x80, 0b11101110, 0x08,&int128);
    // Wake Scheduler
    int_install_ir(0x81, 0b11101110, 0x08,&int129);

    // install IVT
    int_install();
}