//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Desc:       Buffer library                                                //
//                                                                            //
//                                                                            //
//  Copyright © 2018-2019 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 <extras/buf.h>
#include <extras/locks.h>
#include <extras/malloc.h>

#include <kernel/base.h>

Buffer_t *BStdIn, *BStdOut, *BStdDbg;

// Straightforward functions
int BGetFlags(Buffer_t *buf) { return buf->flags; }
int BGetState(Buffer_t *buf) { return buf->state; }

void BEnableLineBuffering(Buffer_t *buf)
{ 
    assert(buf && !(buf->flags & BF_TERM));
    buf->flags |= BF_LINE;
}

void BDisaleLineBuffering(Buffer_t *buf)
{ 
    assert(buf && !(buf->flags & BF_TERM));
    buf->flags &= ~BF_LINE;
}

void BLockBuf(Buffer_t *buf)
{
    assert(buf && buf->initDone == INITOK);
    ExAcquireLock(&buf->lock);
}

void BUnlockBuf(Buffer_t *buf) { ExReleaseLock(&buf->lock); }
bool BTrylockBuf(Buffer_t *buf) { return ExAttemptLock(&buf->lock); }

//
// Closes a buffer, not flushing unless the proper flag is set
//
error_t BCloseBuf(Buffer_t *buf)
{
    assert(buf && buf->initDone == INITOK);
    ExAcquireLock(&buf->lock);

    if (buf->flags & BF_FONCLOSE) {
        BFlushBuf(buf);
    }

    if (buf->flags & BF_SALLOC && buf->buf) {
        KalFreeMemory(buf->buf);
    }

    buf->buf = buf->rp = buf->wp = NULL;
    buf->initDone = buf->flags = buf->state = buf->size = 0;

    ExReleaseLock(&buf->lock);
    
    if (buf->flags & BF_BALLOC) {
        KalFreeMemory(buf);
    }

    return EOK;
}

//
// Creates an actual buffer
//
error_t BOpenPureBuf(Buffer_t **pbuf, int mode, size_t size)
{
    return BOpenPureBufEx(pbuf, NULL, mode, size, NULL);
}

error_t BOpenPureBufEx(Buffer_t **pbuf, char *source, int mode, size_t size,
                       BFlusher_t flusher)
{
    Buffer_t *buf;

    assert(mode == BS_RDWR || mode == BS_RDONLY || mode == BS_WRONLY);

    if (!pbuf) return EINVAL;
    if (!*pbuf) {
        buf = malloc(sizeof *buf);
        if (!buf) return ENOMEM;
        buf->flags |= BF_BALLOC;
    }
    else {
        buf = *pbuf;
        buf->flags = 0;
    }

    ExInitLock(&buf->lock, KLOCK_MUTEX);
    ExAcquireLock(&buf->lock);

    buf->size = size;
    buf->state = mode;

    if (source == NULL) {
        KalAllocMemoryEx((void **)&buf->buf, buf->size, M_ZEROED, 0);
        buf->flags |= BF_SALLOC;
    } else {
        buf->buf = (uchar *)source;
    }

    buf->wp = buf->rp = buf->buf;
    buf->flusher = flusher;
    buf->initDone = INITOK;

    ExReleaseLock(&buf->lock);
    
    // Second allocation failed
    if (buf->buf == NULL) {
        BCloseBuf(buf);
        return ENOMEM;
    }
    
    *pbuf = buf;
    return EOK;
}

//
// Creates a terminal buffer of (nLines + pbCount*nLines) lines each
// of lineLen length (pb = playback buffer, for scrolling up)
//
error_t BOpenTermBuf(Buffer_t **pbuf, int mode,
        int lineLen, int nLines, int pbCount)
{
    return BOpenTermBufEx(pbuf, NULL, mode, lineLen, nLines, pbCount, NULL);
}

error_t BOpenTermBufEx(Buffer_t **pbuf, char *source, int mode,
        int lineLen, int nLines, int pbCount, BFlusher_t flusher)
{
    error_t rc;
    size_t size = lineLen * nLines * (pbCount + 1);

    assert(lineLen > 0 && nLines > 0 && pbCount >= 0);
    
    rc = BOpenPureBufEx(pbuf, source, mode, size, flusher);
    
    if (!rc) {
        (*pbuf)->lastLF = 0;
        (*pbuf)->nLines = nLines;
        (*pbuf)->lineLen = lineLen;
        (*pbuf)->flags |= BF_TERM;
    }
     
    return rc;
}

//
// Flushes a buffer, returns EBADF when not possible
//
error_t BFlushBuf(Buffer_t *buf)
{
    error_t rc;

    assert(buf && buf->initDone == INITOK);

    if (!buf) return EINVAL;
    if (buf->flags & (BF_EOF|BF_ERR)) {
        return EENDF;
    }
    if (!buf->flusher) {
        return EBADF;
    }

    ExAcquireLock(&buf->lock);
    rc = buf->flusher(buf);
    ExReleaseLock(&buf->lock);

    return rc;
}