/* ==================================================================

    FILE: "/home/joze/src/tclreadline/tclreadline.c"
    LAST MODIFICATION: "Fri Aug 20 23:41:24 1999 (joze)"
    (C) 1998, 1999 by Johannes Zellner, <johannes@zellner.org>
    $Id$
    ---

    tclreadline -- gnu readline for tcl
    Copyright (C) 1999  Johannes Zellner

#include <string.h>
#define READLINE_LIBRARY
#include <readline.h>
#include <history.h>

#include <tclreadline.h>

#define MALLOC(size) Tcl_Alloc ((int) size)
#define FREE(ptr) if (ptr) Tcl_Free ((char *) ptr)

enum {
    _CMD_SET     = (1 << 0),
    _CMD_GET     = (1 << 1),
    _CMD_SUB_GET = (1 << 2)
};


typedef struct cmds_t {
    struct cmds_t  *prev;
    char          **cmd;
    struct cmds_t  *next;
} cmds_t;


#define STRIPLEFT(ptr)          \
do {                            \
    char *tmp = ptr;            \
    while (*tmp && *tmp <= ' ') \
        tmp ++;                 \
    strcpy (ptr, tmp);          \
} while (0)

#define STRIPRIGHT(ptr)                                \
do {                                                   \
    char *__tmp__;                                     \
    for (__tmp__ = strchr (ptr, '\0') - 1;             \
         __tmp__ >= ptr && *__tmp__ <= ' '; __tmp__--) \
        *__tmp__ = '\0';                               \
} while (0)

#define STRIPWHITE(ptr) \
do {                    \
    STRIPLEFT (ptr);    \
    STRIPRIGHT (ptr);   \
} while (0)


/*
 * forward declarations.
 */
int    TclReadlineCmd	(ClientData clientData, Tcl_Interp *interp,
                         int argc, char **argv);
void   TclReadlineDataAvailableHandler	(ClientData clientData, int mask);
void   TclReadlineLineCompleteHandler	(char *ptr);
int    Tclreadline_SafeInit	(Tcl_Interp *interp);
int    Tclreadline_Init	(Tcl_Interp *interp);
char*  TclReadlineInitialize	(char *historyfile);
char** TclReadlineCompletion	(char *text, int start, int end);
char*  TclReadline0generator	(char *text, int state);
char*  TclReadline1generator	(char *text, int state);
char*  TclReadlineKnownCommands	(char *text, int state, int mode);
int    TclReadlineEventHook	(void);
int    TclReadlineParse	(char **args, int maxargs, char *buf);

enum { 
    LINE_PENDING,
    LINE_CONTROL_D,
    LINE_COMPLETE
};

static int line_complete = LINE_PENDING;
static char *line = (char *) NULL;


/*
 * Script to set the tclreadline library path in the
 * variable global "tclreadline_library"
 */



int TclReadlineCmd (clientData, interp, argc, argv)
    ClientData clientData;	/* Main window associated with interpreter  */
    Tcl_Interp *interp;		/* Current interpreter                      */
    int argc;			/* Number of arguments                      */
    char **argv;		/* Argument strings                         */

{
    int		c, length;
    

    if (argc < 2) {
	interp->result = "wrong # args";
	for (c = 0; c < argc; c++)
	    fprintf (stderr, "argv[%d] = %s\n", c, argv[c]);
	return TCL_ERROR;
    }

    c = argv[1][0];
    length = strlen(argv[1]);


    if (c == 'r'  && strncmp (argv[1], "read", length) == 0) {
        
        char *expansion = (char *) NULL;
        int status;
        
        line_complete = LINE_PENDING;
        rl_callback_handler_install (argc == 3 ? argv[2] : "%",
                TclReadlineLineCompleteHandler);

        Tcl_CreateFileHandler (0, TCL_READABLE,
                TclReadlineDataAvailableHandler, (ClientData) NULL);

        while (LINE_PENDING == line_complete) {
            Tcl_DoOneEvent (0);
        }

        Tcl_DeleteFileHandler (0);


	if (LINE_CONTROL_D == line_complete) {
	    Tcl_Eval (interp, "puts {}; exit");
	}


        status = history_expand (line, &expansion);
        if (status == 1)
            printf ("%s\n", expansion);
        else if (status == -1)
            Tcl_AppendResult (interp, "error in history expansion\n",
                    (char *) NULL);
        
        if (expansion && *expansion)
            add_history (expansion);

        Tcl_AppendResult (interp, expansion, (char *) NULL);

        FREE (line);
        FREE (expansion);
        return TCL_OK;
    }
    else if (c == 'i'  && strncmp (argv[1], "initialize", length) == 0) {
        if (argc != 3)
            goto BAD_COMMAND;
        else
            Tcl_AppendResult (interp, TclReadlineInitialize (argv[2]),
                    (char *) NULL);
    }
    else if (c == 'w'  && strncmp (argv[1], "write", length) == 0) {
        if (argc != 3)
            goto BAD_COMMAND;
        else if (write_history (argv[2]))
            Tcl_AppendResult (interp, "unable to write history to \"",
                    argv[2], "\"\n", (char *) NULL);
    }
    else if (c == 'a'  && strncmp (argv[1], "add", length) == 0) {
        if (argc != 3)
            goto BAD_COMMAND;
        else if (TclReadlineKnownCommands (argv[2], (int) 0, _CMD_SET))
            Tcl_AppendResult (interp, "unable to add command \"",
                    argv[2], "\"\n", (char *) NULL);
    }
    else if (c == 'c'  && strncmp (argv[1], "complete", length) == 0) {
        if (argc != 3)
            goto BAD_COMMAND;
        else if (Tcl_CommandComplete (argv[2]))
            Tcl_AppendResult (interp, "1", (char *) NULL);
        else
            Tcl_AppendResult (interp, "0", (char *) NULL);
    }
    else
        goto BAD_COMMAND;


    return TCL_OK;

BAD_COMMAND:
    Tcl_AppendResult (interp,
            "wrong # args: should be \"readline option ?arg ...?\"",
	    (char *) NULL);
    return TCL_ERROR;

}


void TclReadlineDataAvailableHandler (ClientData clientData, int mask)
{
#if 0
    fprintf (stderr, "(TclReadlineDataAvailableHandler) mask = %d\n",  mask);
#endif
    if (mask & TCL_READABLE) {

        rl_callback_read_char ();
        rl_redisplay ();
    }
}


void TclReadlineLineCompleteHandler (char *ptr)
{
#if 0
    fprintf (stderr, "(TclReadlineLineCompleteHandler)  ptr = %p\n",  ptr);
    if (ptr)
    fprintf (stderr, "(TclReadlineLineCompleteHandler) *ptr = %p\n", *ptr);
#endif
    if (!ptr) { /* <c-d> */
        line_complete = LINE_CONTROL_D;
        rl_callback_handler_remove ();
    } else if (*ptr) {
        line_complete = LINE_COMPLETE;
        rl_callback_handler_remove ();
        line = ptr;
    }





}



int Tclreadline_SafeInit (Tcl_Interp *interp)
{
    return Tclreadline_Init (interp);
}


int Tclreadline_Init (Tcl_Interp *interp)
{
    Tcl_CreateCommand (interp, "::tclreadline::readline", TclReadlineCmd,
	    (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    return Tcl_PkgProvide (interp, "tclreadline", TCLREADLINE_VERSION);
}


char *TclReadlineInitialize (char *historyfile)
{

    rl_readline_name = "tclreadline";
    using_history ();

    /*
     * try to read historyfile in home
     * directory. If this failes, this
     * is *not* an error.
     */
    rl_attempted_completion_function = (CPPFunction *) TclReadlineCompletion;
    if (read_history (historyfile))
        return "unable to read history file";
    
    else
        return "";
}


char **TclReadlineCompletion (char *text, int start, int end)
{
    char **matches = (char **) NULL;
    static char local_line[BUFSIZ];
       
    strcpy (local_line, rl_line_buffer);
    
    STRIPWHITE (local_line);
    
    /*
    fprintf (stderr, "DEBUG> TclReadlineCompletion: text=|%s|\n", text);
    fprintf (stderr, "DEBUG> TclReadlineCompletion: start=|%d|\n", start);
    fprintf (stderr, "DEBUG> TclReadlineCompletion: end=|%d|\n", end);
    */

    if (start == 0 || !strlen (local_line))
        matches = completion_matches (text, TclReadline0generator);
    else
        matches = completion_matches (text, TclReadline1generator);
    
    return matches;
}


char *TclReadline0generator (char *text, int state)
{
    return TclReadlineKnownCommands (text, state, _CMD_GET);
}


char *TclReadline1generator (char *text, int state)
{
    return TclReadlineKnownCommands (text, state, _CMD_SUB_GET);
}


char *TclReadlineKnownCommands (char *text, int state, int mode)
{
    static int len;
    static cmds_t *cmds = (cmds_t *) NULL, *new;

    char *tmp, *args[256];
    int i, argc;
    char **name;
    
    switch (mode) {
        
        case _CMD_SET:

            new = (cmds_t *) MALLOC (sizeof (cmds_t));
            new->next = (cmds_t *) NULL;

            if (!cmds) {
                cmds = new;
                cmds->prev = new;
            }
            else {
                cmds->prev->next = new;
                cmds->prev = new;
            }

            tmp = strdup (text);
            argc = TclReadlineParse (args, sizeof (args), tmp);

            new->cmd = (char **) MALLOC (sizeof (char *) * (argc + 1));

            for (i = 0; i < argc; i++)
                new->cmd[i] = args[i];

            new->cmd[argc] = (char *) NULL;

            return (char *) NULL;
            break;


        case _CMD_GET:


            if (!state) {
                new = cmds;
                len = strlen (text);
            }

            while (new && (name = new->cmd)) {
                new = new->next;
                if (!strncmp (name[0], text, len))
                    return strdup (name[0]);
            }

            return (char *) NULL;
            break;

        case _CMD_SUB_GET:
            

            if (!state) {

                int sub;
                char *local_line = strdup (rl_line_buffer);
                
                len = strlen (local_line);
                STRIPRIGHT (local_line);

                if (len != strlen (local_line))
                    sub = TclReadlineParse (args, sizeof (args), local_line);
                else
                    sub = TclReadlineParse (args,
                                            sizeof (args), local_line) - 1;
                
                new = cmds;
                len = strlen (text);
                
                while (new && (name = new->cmd)) {
                    if (!strcmp (name[0], args[0]))
                        break;
                    new = new->next;
                }
                
                if (!new)
                    return (char *) NULL;

                for (i = 0; new->cmd[i]; i++) /* EMPTY */;

                if (sub < i && !strncmp (new->cmd[sub], text, len))
                    return strdup (new->cmd[sub]);
                else
                   return (char *) NULL;

            }
            else
                return (char *) NULL;

            /* NOTREACHED */
            break;


        default:
            return (char *) NULL;
            break;

    }
    
    /* NOTREACHED */

}

int TclReadlineEventHook (void)
{
    Tcl_DoOneEvent (TCL_ALL_EVENTS | TCL_DONT_WAIT);
    return TCL_OK;
}

int TclReadlineParse (char **args, int maxargs, char *buf)
{
    int nr = 0;

    while (*buf != '\0' && nr < maxargs) {
        /*
         * Strip whitespace.  Use nulls, so
         * that the previous argument is terminated

        while ((*buf!='\0') && (*buf!=' ') && (*buf!='\t') && (*buf!='\n'))
            buf++;
    }

    *args = '\0';
    return nr;

}