#include "interrupts.h"

#include "kernel.h"
#include "log.h"
#include "e1000.h"
#include "asm_int.h"
#include "asm_pit.h"
#include "driver/mouse.h"
#include "driver/keyboard.h"
#include "scheduler.h"
#include "asm_x86.h"
#include "smp.h"
#include "apic.h"
#include "ringbuffer.h"
#include "compositor.h"
#include "syscalls.h"

/** The size of our interrupts table  */
#define INT_MAX 256 // 0-255

/** Addresses of the registered interrupt handlers */
static uint32_t handlers[INT_MAX]; 

/** The interrupt descriptor table */
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 */
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;
}

/** 
 * Register an interrupt handler for a given irq number.
 *
 * Some general notes on interrupts 
 * (TODO: consider moving this somewehre else)
 * 
 * 1) In case of a syscall (coming from userspace) the handler should:
 *    a) For a blocking call, set required params and call the scheduler!
 *    b) Otherweise call x86_sti() by itself as soon as possiblle to 
 *       reenable interrupts.
 * 
 * 2) In case of APIC Timer interrupt call the scheduler.
 *
 * 3) Keyboard, Mouse, E1000, PIT
 *      just push your stuff somewhere for later processing as fast as 
 *      you can and reschedule to a kernel worker OR just iret. 
 *
 * 4) IPI
 *      we use them to force rescheduling only now
 *      treated in the same way as a APIC Timer interrupt... 
 *      TODO: NOT CALL THIS IPI!! since we send it only on same cpu now :P
 *
 * NOTE: apic_eoi() should be called in all cases except the syscalls,
 *       to signal the "end of interrupt" to the APIC.
 *
 * TODO: REMEMBER THAT WE WILL HAVE TO CHECK ALL OUR SYSCALL ARE REENTRANT!
 *       ALSO IN MULTICPU SETTINGS! (check the userspace wrappers as well!)
 *       EACH prog requires a sufficient kernel-stack as well! (check this!)
 *       WE CAN GUARD with spinlocks / disabling interrupts when really needed....
 *
 */

void interrupt_register(uint32_t irq, uint32_t func_addr)
{
    if(irq<128||irq>160)kpanic("irq number out of range!");
    if(handlers[irq]!=0)kpanic("handler already registered!");
    handlers[irq]=func_addr;
}

/*
 * Interrupt dispatcher 
 * Remeber that we are inside an interrupt here!
 */
uint32_t interrupt_handler(uint32_t esp, uint32_t irq)
{
    uint32_t cpu=smp_get(SMP_APIC_ID);
    
    if(handlers[irq]!=0)// kb,mouse,e1000,pit,...
    {
        uint32_t (*f)(uint32_t esp)=handlers[irq];
        esp=f(esp);
        if(irq!=INTERRUPT_SYSCALL)apic_eoi();  
        return esp;
    }

    if(irq==INTERRUPT_APIC_TIMER || irq==INTERRUPT_IPI)
    {
        if(cpu==0) // thi
        { 
            // limit compositor to APIC_TIMER freq.(60hz?)
            if(irq==INTERRUPT_APIC_TIMER)compositor_wake();
        }

        esp=scheduler_run(esp,-1); // just schedule to next task
        apic_eoi();
        return esp;
    }

    if(irq==INTERRUPT_SYSCALL)
    {
            int pid=task_get_current_pid();
            uint32_t *stack;
            stack=esp; 
            task_set_esp(pid,esp); // this will get fucked if we get scheduled away...

            // extract variables from stack 
            // (NOTE we pass them in some fucked up order, 
            // they were pushed via pusha!
            uint32_t eax=stack[11];
            uint32_t ebx=stack[8];
            uint32_t ecx=stack[10]; 
            uint32_t edx=stack[9];

            // only chance to do somehting before we reenable interrupts!
            syscall_generic_prep(eax,edx,ecx,ebx,pid);

            // now we don't give a shit about gettting interrupted, yeah!
            // this is guaranteed to cause heavy troubles... since we are 
            // not reentrant and do not guard anythin..

            // keep brute force rescheduling till' we get through....
            // TODO: implement some waiting queue and wake only if there 
            // is any chance this will not fail again and again and again..
            // TODO: get rid of this big KERNEL LOCK
            // it will also not work with SMP
            while(true)
            {
                int ok=syscall_generic_test(eax,edx,ecx,ebx,pid);
                if(ok)break;
                __asm__("int $0x81");// does NOT requie interrupts
            }

            // uff, once we got through we can do the syscall and get out
            // of this place...
        //    x86_cli(); 
            uint32_t ret=syscall_generic(eax,edx,ecx,ebx,pid);
          //  x86_sti(); 

            stack[12]=0x1;  // indicate with 0x1 we WANT to set a return 
                            // value in ebx (0x0 will skip it)
            stack[13]=ret;  // and THIS is our return value!

            #ifdef LOG_SYSCALLS
            klog("syscall ret=0x%08X",ret);
            #endif

            //__asm__("int $0x81");
            return esp; // return to asm interrupt handler... and iret.
    }

    kpanic("unhandled interrupt %d",irq);
}

/**
 * init interrupt descriptor table (TODO; do we seriously have to hardcode this?)
 */
void interrupts_init()
{
    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, 0x08,&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);
    int_install_ir(19, 0b10001110, 0x08,&exc19);
    int_install_ir(20, 0b10001110, 0x08,&exc20);
    int_install_ir(21, 0b10001110, 0x08,&exc21);
    int_install_ir(22, 0b10001110, 0x08,&exc22);
    int_install_ir(23, 0b10001110, 0x08,&exc23);
    int_install_ir(24, 0b10001110, 0x08,&exc24);
    int_install_ir(25, 0b10001110, 0x08,&exc25);
    int_install_ir(26, 0b10001110, 0x08,&exc26);
    int_install_ir(27, 0b10001110, 0x08,&exc27);
    int_install_ir(28, 0b10001110, 0x08,&exc28);
    int_install_ir(29, 0b10001110, 0x08,&exc29);
    int_install_ir(30, 0b10001110, 0x08,&exc30);
    int_install_ir(31, 0b10001110, 0x08,&exc31);
    
    // System Calls (User Software / Ring 3) 
    int_install_ir(128, 0b11101110, 0x08,&int128);

    // Ring 1 only
    int_install_ir(129,   0b10001110, 0x08,&int129);
    int_install_ir(130,   0b10001110, 0x08,&int130);
    int_install_ir(131,   0b10001110, 0x08,&int131);
    int_install_ir(132,   0b10001110, 0x08,&int132);
    int_install_ir(133,   0b10001110, 0x08,&int133);
    int_install_ir(134,   0b10001110, 0x08,&int134);
    int_install_ir(135,   0b10001110, 0x08,&int135);
    int_install_ir(136,   0b10001110, 0x08,&int136);
    int_install_ir(137,   0b10001110, 0x08,&int137);
    int_install_ir(138,   0b10001110, 0x08,&int138);
    int_install_ir(139,   0b10001110, 0x08,&int139);
    int_install_ir(140,   0b10001110, 0x08,&int140);
    int_install_ir(141,   0b10001110, 0x08,&int141);
    int_install_ir(142,   0b10001110, 0x08,&int142);
    int_install_ir(143,   0b10001110, 0x08,&int143);
    int_install_ir(144,   0b10001110, 0x08,&int144);
    int_install_ir(145,   0b10001110, 0x08,&int145);
    int_install_ir(146,   0b10001110, 0x08,&int146);
    int_install_ir(147,   0b10001110, 0x08,&int147);
    int_install_ir(148,   0b10001110, 0x08,&int148);
    int_install_ir(149,   0b10001110, 0x08,&int149);
    int_install_ir(150,   0b10001110, 0x08,&int150);
    int_install_ir(151,   0b10001110, 0x08,&int151);
    int_install_ir(152,   0b10001110, 0x08,&int152);
    int_install_ir(153,   0b10001110, 0x08,&int153);
    int_install_ir(154,   0b10001110, 0x08,&int154);
    int_install_ir(155,   0b10001110, 0x08,&int155);
    int_install_ir(156,   0b10001110, 0x08,&int156);
    int_install_ir(157,   0b10001110, 0x08,&int157);
    int_install_ir(158,   0b10001110, 0x08,&int158);
    int_install_ir(159,   0b10001110, 0x08,&int159);
    int_install_ir(160,   0b10001110, 0x08,&int160);
}

/** Installs the interrupt table */
void interrupts_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));
}