//----------------------------------------------------------------------------//
//                                OS on Kaleid                                //
//                                                                            //
//  Desc:  Basic Keyboard Driver                                              //
//                                                                            //
//                                                                            //
//  Copyright © 2018-2021 The OS/K Team                                       //
//                                                                            //
//  This file is part of OS/K.                                                //
//                                                                            //
//  OS/K is free software: you can redistribute it and/or modify              //
//  it under the terms of the GNU General Public License as published by      //
//  the Free Software Foundation, either version 3 of the License, or         //
//  any later version.                                                        //
//                                                                            //
//  OS/K is distributed in the hope that it will be useful,                   //
//  but WITHOUT ANY WARRANTY//without even the implied warranty of            //
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             //
//  GNU General Public License for more details.                              //
//                                                                            //
//  You should have received a copy of the GNU General Public License         //
//  along with OS/K.  If not, see <https://www.gnu.org/licenses/>.            //
//----------------------------------------------------------------------------//

#include <libbuf.h>
#include <io/keyb.h>
#include <ke/idt.h>

#include "scan.c"

#define KEY(code) (table[2*(code)])
#define FLAGS(code) (table[2*(code)+1])

static bool capsLockActive = 0;

static bool e0received = 0;
static bool altPressed = 0;
static bool altGrPressed = 0;
static bool shiftPressed = 0;
static bool controlPressed = 0;

static void KeybPrint(uchar _code)
{    
    uint code = (uint)_code;

    const uint *table;
    
    if (!e0received) {
        table = (altPressed ? LeftAltScanCodes
                : (controlPressed ? LeftControlScanCodes
                : (shiftPressed ? LeftShiftScanCodes
                : (altGrPressed ? AltGrScanCodes
                : RegularScanCodes))));
    } else {
        table = E0ScanCodes;
        e0received = 0;
    }

    if ((capsLockActive && (FLAGS(code) & CAPSLOCK))
                        && !(altPressed || controlPressed)) {
        if (shiftPressed)
            table = RegularScanCodes;
        else
            table = LeftShiftScanCodes;
    }

    uchar ch = KEY(code);
    
    if (!ch) {
        switch (code) {
        case 0xE0: e0received = 1; break;

        case 0x38: if (table == E0ScanCodes) altGrPressed = 1;
                   else altPressed = 1;
                   break;
        case 0xB8: if (table == E0ScanCodes) altGrPressed = 0;
                   else altPressed = 0;
                   break;

        case 0x36: case 0x2A: shiftPressed = 1; break;
        case 0xB6: case 0xAA: shiftPressed = 0; break;

        case 0x1D: controlPressed = 1; break;
        case 0x9D: controlPressed = 0; break;
        
        case 0x3A: capsLockActive = !capsLockActive; break;
        }
        return;
    }
    
    bputc(BStdIn, ch);
}

static void KeybHandler(ISRFrame_t *regs)
{
    char status;
    uchar code = 0;

    // write EOI
    IoWriteByteOnPort(0x20, 0x20);

    status = IoReadByteFromPort(0x64);

    if (status & 0x01) {
        code = IoReadByteFromPort(0x60);
    }
    KeybPrint(code);
    KeSendEOItoPIC(0x21);
}

void IoCreateInputBuffer(void)
{
    error_t rc;

    rc = BOpenPureBuf(&BStdIn, BS_RDWR, 4 * KB);

    if (rc) KeStartPanic("[Keyb] Couldn't create BStdIn");

    //BEnableLineBuffering(BStdIn);
    BStdIn->flusher = bemptybuf;
}

void IoEnableKeyb(void)
{
    ulong flags = KePauseIRQs();
 
    KeRegisterISR(KeybHandler, 0x21);
    KeUnmaskIRQ(0x1);
    KeRestoreIRQs(flags);

    KeEnableNMI();
    
    IoCreateInputBuffer();
}