//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Desc:       Terminal-related functions                                    //
//                                                                            //
//                                                                            //
//  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 <kernel/term.h>

extern void       VGA_Init(void);
extern Terminal_t VGA_Terminal;

//
// Initializes standard output
//
void InitTerms(void)
{
    KalAssert(!StdOut && !StdDbg);

    VGA_Init();

    StdDbg = &VGA_Terminal;
    StdOut = &VGA_Terminal;

    ClearTerm(StdOut);
}

//
// Fills terminal with spaces
//
error_t ClearTerm(Terminal_t *term)
{
    error_t retcode;

    if (term == NULL) return EINVAL;
    KalAssert(term->initDone == INITOK);

    AcquireLock(&term->lock);
    retcode = term->clear(term);
    ReleaseLock(&term->lock);

    return retcode;
}

//
// Changes the color code
//
error_t ChTermColor(Terminal_t *term, TermColor_t fgColor, TermColor_t bgColor)
{
    if (fgColor > KTERM_COLOR_WHITE || bgColor > KTERM_COLOR_WHITE)
        return EINVAL;

    if (term == NULL)
        return EINVAL;

    AcquireLock(&term->lock);

    term->fgColor = fgColor;
    term->bgColor = bgColor;

    ReleaseLock(&term->lock);

    return EOK;
}

//
// Writes a single character on the terminal (UNLOCKED version)
//
error_t PutOnTermUnlocked(Terminal_t *term, char ch)
{
    uint i;
    size_t prevY;
    error_t rc = EOK;

    if (ch == '\r') {
        term->currentX = 0;
        return EOK;
    }

    // Line feed first takes us to the very end of the line
    // Later in this function we actually do the line feed
    else if (ch == '\n') {
        term->currentX = term->width - 1;
    }

    // Tabulations account for "term->tabSize" spaces
    else if (ch == '\t') {
        prevY = term->currentX;
        for (i = 0; i < term->tabSize; i++) {
            // Make sure tabulations can't spread over two lines
            if (term->currentX == prevY) {
                rc = term->putchar(term, ' ');
                if (rc) return rc;
            }
        }
    }

    else rc = term->putchar(term, ch);

    // Did we reach the end of line?
    if (!rc && ++term->currentX == term->width) {
        term->currentX = 0;

        // Did we reach the buffer's end?
        if (++term->currentY == term->height) {
            term->currentY = 0;
        }
    }

    return rc;
}


//
// Writes a single character on the terminal (LOCKED version)
//
error_t PutOnTerm(Terminal_t *term, char ch)
{
    error_t rc;

    if (term == NULL) return EINVAL;
    KalAssert(term->initDone == INITOK);

    AcquireLock(&term->lock);
    rc = PutOnTermUnlocked(term, ch);
    ReleaseLock(&term->lock);

    return rc;
}

//
// Prints string on terminal (UNLOCKED version)
//
error_t PrintOnTermUnlocked(Terminal_t *term, const char *str)
{
    error_t rc = EOK;

    while (*str && rc == EOK) {
        rc = PutOnTermUnlocked(term, *str++);
    }

    return rc;
}

//
// Prints string on terminal (LOCKED version)
//
error_t PrintOnTerm(Terminal_t *term, const char *str)
{
    error_t rc = EOK;

    if (term == NULL) return EINVAL;
    KalAssert(term->initDone == INITOK);

    AcquireLock(&term->lock);
    rc = PrintOnTermUnlocked(term, str);
    ReleaseLock(&term->lock);

    return rc;
}

//
// Prints formatted string on standard output
// Prints at most KLOG_MAX_BUFSIZE characters
//
error_t KernLog(const char *fmt, ...)
{
    va_list ap;

    char logbuf[KLOG_MAX_BUFSIZE];

    va_start(ap, fmt);
    vsnprintf(logbuf, KLOG_MAX_BUFSIZE, fmt, ap);
    va_end(ap);

    return PrintOnTerm(StdOut, logbuf);
}

#ifndef _NO_DEBUG
//
// Prints formatted string on debug output
// Prints at most KLOG_MAX_BUFSIZE characters
//
error_t DebugLog(const char *fmt, ...)
{
    va_list ap;

    char logbuf[KLOG_MAX_BUFSIZE];

    va_start(ap, fmt);
    vsnprintf(logbuf, KLOG_MAX_BUFSIZE, fmt, ap);
    va_end(ap);

    return PrintOnTerm(StdDbg, logbuf);
}
#endif