//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Desc:       Kernel shell                                                  //
//                                                                            //
//                                                                            //
//  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 <io/vga.h>
#include <io/keyb.h>
#include <io/spkr.h>
#include <lib/buf.h>
#include <sh/argv.h>
#include <sh/shell.h>
#include <po/shtdwn.h>

int shargc = 0;
char **shargv = 0;
int shcol = VGA_COLOR_LIGHT_GREY;

static char *argvbuf = 0;

void ExecuteCommand(char *cmdbuf, Command_t *cmdtable)
{
    error_t rc;
    Command_t *cmd;
    bool found = false;
    
    if (!cmdbuf || !*cmdbuf)
        return;

    memzero(*shargv, ARG_MAX);
    rc = ShCmdLineToArgVec(cmdbuf, &shargc, argvbuf);
    if (rc) KeStartPanic("Shell: Couldn't parse command line: %d", rc);

    for (cmd = cmdtable; cmd->name != NULL; cmd++) {
        if (!strcmp(cmd->name, shargv[0])) {
            cmd->func(shargc, shargv, cmdbuf);
            found = true;
            break;
        }
    }
    
    assert(shargv[0] == argvbuf + ARG_MAX);
    
    if (found == false) {
        KernLog("err: command not found: '%.255s' (%ld)\n",
                    shargv[0], strlen(shargv[0]));
    }
}

void ShStartShell(void)
{
    uchar ch;
    error_t rc;
    
    char *cmdbuf = malloc(CMDBUFSIZE);
    char *bufptr = cmdbuf;

    argvbuf = malloc(ARG_MAX * 2);
    memzero(argvbuf, ARG_MAX * 2);
    shargv = (char **)argvbuf;

    KernLog("\n%Cshell> %C", VGA_COLOR_WHITE, shcol);
    BFlushBuf(BStdOut);

    while ((rc = BGetFromBuf(BStdIn, &ch)) == EOK || rc == EENDF) {
        // Reset BStdIn's content
        if (rc == EENDF) {
            if (!(BStdIn->flags & BF_ERR)) {
                *bufptr = 0;
                bufptr = cmdbuf;
                ExecuteCommand(cmdbuf, shcmdtable);

                memzero(cmdbuf, CMDBUFSIZE);
                BFlushBuf(BStdIn);
                KernLog("%Cshell> %C", VGA_COLOR_WHITE, shcol);
                BFlushBuf(BStdOut);
            }
            else break;
        }
    
        switch (ch) {

        case KEY_BS:
            *bufptr = 0;
            if (bufptr > cmdbuf) {
                bufptr--;
            }
            break;

        case KEY_BEL:
            if (rand() % 16 == 0) {
                IoDoStarWars();
            }
            else IoDoBeep();
            break;

        case KEY_DC1:
            IoScrollUp();
            break;

        case KEY_DC2:
            IoScrollDown();
            break;

        case KEY_ESC:
            PoShutdown();
            break;
            
        default:

            while (IoGetScroll() > 0) {
                IoScrollDown();
            }

            *bufptr++ = (char)ch;

            // End of buffer?
            if (bufptr != cmdbuf+CMDBUFSIZE-1) {
                break; // No
            }

            KernLog("\n");
            // Else, fallthrough to case '\n'

       case '\n':
            
            while (IoGetScroll() > 0) {
                IoScrollDown();
            }

            *bufptr = 0;
            bufptr = cmdbuf;
            ExecuteCommand(cmdbuf, shcmdtable);

            memzero(cmdbuf, CMDBUFSIZE);
            KernLog("%Cshell> %C", VGA_COLOR_WHITE, shcol);
            BFlushBuf(BStdIn);
            BFlushBuf(BStdOut);
            break;
        }

        KePauseCPU();
    }
    KernLog("[EOI]\n");
}