/*
 * tkcond.c
 *
 * Eric Youngdale was the original author of xconfig.
 * Michael Elizabeth Chastain (mec@shout.net) is the current maintainer.
 *
 * This file takes the tokenized statement list and transforms 'if ...'
 * statements.  For each simple statement, I find all of the 'if' statements
 * that enclose it, and attach the aggregate conditionals of those 'if'
 * statements to the cond list of the simple statement.
 *
 * 14 January 1999, Michael Elizabeth Chastain, <mec@shout.net>
 * - Steam-clean this file.  I tested this by generating kconfig.tk for
 *   every architecture and comparing it character-for-character against
 *   the output of the old tkparse.
 *
 * 07 July 1999, Andrzej M. Krzysztofowicz <ankry@mif.pg.gda.pl>
 * - kvariables removed; all variables are stored in a single table now
 * - some elimination of options non-valid for current architecture
 *   implemented.
 * - negation (!) eliminated from conditions
 *
 * TO DO:
 * - xconfig is at the end of its life cycle.  Contact <mec@shout.net> if
 *   you are interested in working on the replacement.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "tkparse.h"



/*
 * Mark variables which are defined anywhere.
 */
static void mark_variables( struct kconfig * scfg )
{
    struct kconfig * cfg;
    int i;

    for ( i = 1; i <= max_varnum; i++ )
        vartable[i].defined = 0;
    for ( cfg = scfg; cfg != NULL; cfg = cfg->next )
    {
        if ( cfg->token == token_bool
        ||   cfg->token == token_choice_item
        ||   cfg->token == token_define_bool
        ||   cfg->token == token_define_hex
        ||   cfg->token == token_define_int
        ||   cfg->token == token_define_string
        ||   cfg->token == token_define_tristate
        ||   cfg->token == token_dep_bool
        ||   cfg->token == token_dep_mbool
        ||   cfg->token == token_dep_tristate
        ||   cfg->token == token_hex
        ||   cfg->token == token_int
        ||   cfg->token == token_string
        ||   cfg->token == token_tristate
        ||   cfg->token == token_unset )
        {
            if ( cfg->nameindex > 0 )   /* paranoid */
            {
                vartable[cfg->nameindex].defined = 1;
            }
        }
    }
}



static void free_cond( struct condition *cond )
{
    struct condition *tmp, *tmp1;
    for ( tmp = cond; tmp; tmp = tmp1 )
    {
        tmp1 = tmp->next;
        free( (void*)tmp );
    }
}



/*
 * Remove the bang operator from a condition to avoid priority problems.
 * "!" has different priorities as "test" command argument and in 
 * a tk script.
 */
static struct condition * remove_bang( struct condition * condition )
{
    struct condition * conda, * condb, * prev = NULL;

    for ( conda = condition; conda; conda = conda->next )
    {
        if ( conda->op == op_bang && conda->next &&
           ( condb = conda->next->next ) )
        {
            if ( condb->op == op_eq || condb->op == op_neq )
            {
                condb->op = (condb->op == op_eq) ? op_neq : op_eq;
                conda->op = op_nuked;
                if ( prev )
                {
                    prev->next = conda->next;
                }
                else
                {
                    condition = conda->next;
                }
                conda->next = NULL;
                free_cond( conda );
                conda = condb;
            }
        }
        prev = conda;
    }
    return condition;
}



/*
 * Make a new condition chain by joining the current condition stack with
 * the "&&" operator for glue.
 */
static struct condition * join_condition_stack( struct condition * conditions [],
    int depth )
{
    struct condition * cond_list;
    struct condition * cond_last;
    int i, is_first = 1;

    cond_list = cond_last = NULL;

    for ( i = 0; i < depth; i++ )
    {
        if ( conditions[i]->op == op_false )
        {
            struct condition * cnew;

            /* It is always false condition */
            cnew = malloc( sizeof(*cnew) );
            memset( cnew, 0, sizeof(*cnew) );
            cnew->op = op_false;
            cond_list = cond_last = cnew;
            goto join_done;
        }
    }
    for ( i = 0; i < depth; i++ )
    {
        struct condition * cond;
        struct condition * cnew;
        int add_paren;

        /* omit always true conditions */
        if ( conditions[i]->op == op_true )
            continue;

        /* if i have another condition, add an '&&' operator */
        if ( !is_first )
        {
            cnew = malloc( sizeof(*cnew) );
            memset( cnew, 0, sizeof(*cnew) );
            cnew->op = op_and;
            cond_last->next = cnew;
            cond_last = cnew;
        }

        if ( conditions[i]->op != op_lparen )
        {
            /* add a '(' */
            add_paren = 1;
            cnew = malloc( sizeof(*cnew) );
            memset( cnew, 0, sizeof(*cnew) );
            cnew->op = op_lparen;
            if ( cond_last == NULL )
                { cond_list = cond_last = cnew; }
            else
                { cond_last->next = cnew; cond_last = cnew; }
        }
        else
        {
            add_paren = 0;
        }

        /* duplicate the chain */
        for ( cond = conditions [i]; cond != NULL; cond = cond->next )
        {
            cnew            = malloc( sizeof(*cnew) );
            cnew->next      = NULL;
            cnew->op        = cond->op;
            cnew->str       = cond->str ? strdup( cond->str ) : NULL;
            cnew->nameindex = cond->nameindex;
            if ( cond_last == NULL )
                { cond_list = cond_last = cnew; }
            else
                { cond_last->next = cnew; cond_last = cnew; }
        }

        if ( add_paren )
        {
            /* add a ')' */
            cnew = malloc( sizeof(*cnew) );
            memset( cnew, 0, sizeof(*cnew) );
            cnew->op = op_rparen;
            cond_last->next = cnew;
            cond_last = cnew;
        }
        is_first = 0;
    }

    /*
     * Remove duplicate conditions.
     */
    {
        struct condition *cond1, *cond1b, *cond1c, *cond1d, *cond1e, *cond1f;

        for ( cond1 = cond_list; cond1 != NULL; cond1 = cond1->next )
        {
            if ( cond1->op == op_lparen )
            {
                cond1b = cond1 ->next; if ( cond1b == NULL ) break;
                cond1c = cond1b->next; if ( cond1c == NULL ) break;
                cond1d = cond1c->next; if ( cond1d == NULL ) break;
                cond1e = cond1d->next; if ( cond1e == NULL ) break;
                cond1f = cond1e->next; if ( cond1f == NULL ) break;

                if ( cond1b->op == op_variable
                && ( cond1c->op == op_eq || cond1c->op == op_neq )
                &&   cond1d->op == op_constant 
                &&   cond1e->op == op_rparen )
                {
                    struct condition *cond2, *cond2b, *cond2c, *cond2d, *cond2e, *cond2f;

                    for ( cond2 = cond1f->next; cond2 != NULL; cond2 = cond2->next )
                    {
                        if ( cond2->op == op_lparen )
                        {
                            cond2b = cond2 ->next; if ( cond2b == NULL ) break;
                            cond2c = cond2b->next; if ( cond2c == NULL ) break;
                            cond2d = cond2c->next; if ( cond2d == NULL ) break;
                            cond2e = cond2d->next; if ( cond2e == NULL ) break;
                            cond2f = cond2e->next;

                            /* look for match */
                            if ( cond2b->op == op_variable
                            &&   cond2b->nameindex == cond1b->nameindex
                            &&   cond2c->op == cond1c->op
                            &&   cond2d->op == op_constant
                            &&   strcmp( cond2d->str, cond1d->str ) == 0
                            &&   cond2e->op == op_rparen )
                            {
                                /* one of these must be followed by && */
                                if ( cond1f->op == op_and
                                || ( cond2f != NULL && cond2f->op == op_and ) )
                                {
                                    /* nuke the first duplicate */
                                    cond1 ->op = op_nuked;
                                    cond1b->op = op_nuked;
                                    cond1c->op = op_nuked;
                                    cond1d->op = op_nuked;
                                    cond1e->op = op_nuked;
                                    if ( cond1f->op == op_and )
                                        cond1f->op = op_nuked;
                                    else
                                        cond2f->op = op_nuked;
                                }
                            }
                        }
                    }
                }
            }
        }
    }

join_done:
    return cond_list;
}



static char * current_arch = NULL;

/*
 * Eliminating conditions with ARCH = <not current>.
 */
static struct condition *eliminate_other_arch( struct condition *list )
{
    struct condition *cond1a = list, *cond1b = NULL, *cond1c = NULL, *cond1d = NULL;
    if ( current_arch == NULL )
        current_arch = getenv( "ARCH" );
    if ( current_arch == NULL )
    {
        fprintf( stderr, "error: ARCH undefined\n" );
        exit( 1 );
    }
    if ( cond1a->op == op_variable
    && ! strcmp( vartable[cond1a->nameindex].name, "ARCH" ) )
    {
        cond1b = cond1a->next; if ( cond1b == NULL ) goto done;
        cond1c = cond1b->next; if ( cond1c == NULL ) goto done;
        cond1d = cond1c->next;
        if ( cond1c->op == op_constant && cond1d == NULL )
        {
            if ( (cond1b->op == op_eq && strcmp( cond1c->str, current_arch ))
            ||   (cond1b->op == op_neq && ! strcmp( cond1c->str, current_arch )) )
            {
                /* This is for another architecture */ 
                cond1a->op = op_false;
                cond1a->next = NULL;
                free_cond( cond1b );
                return cond1a;
            }
            else if ( (cond1b->op == op_neq && strcmp( cond1c->str, current_arch ))
                 ||   (cond1b->op == op_eq && ! strcmp( cond1c->str, current_arch )) )
            {
                /* This is for current architecture */
                cond1a->op = op_true;
                cond1a->next = NULL;
                free_cond( cond1b );
                return cond1a;
            }
        }
        else if ( cond1c->op == op_constant && cond1d->op == op_or )
        {
            if ( (cond1b->op == op_eq && strcmp( cond1c->str, current_arch ))
            ||   (cond1b->op == op_neq && ! strcmp( cond1c->str, current_arch )) )
            {
                /* This is for another architecture */ 
                cond1b = cond1d->next;
                cond1d->next = NULL;
                free_cond( cond1a );
                return eliminate_other_arch( cond1b );
            }
            else if ( (cond1b->op == op_neq && strcmp( cond1c->str, current_arch ))
                 || (cond1b->op == op_eq && ! strcmp( cond1c->str, current_arch )) )
            {
                /* This is for current architecture */
                cond1a->op = op_true;
                cond1a->next = NULL;
                free_cond( cond1b );
                return cond1a;
            }
        }
        else if ( cond1c->op == op_constant && cond1d->op == op_and )
        {
            if ( (cond1b->op == op_eq && strcmp( cond1c->str, current_arch ))
            ||   (cond1b->op == op_neq && ! strcmp( cond1c->str, current_arch )) )
            {
                /* This is for another architecture */
                int l_par = 0;
                
                for ( cond1c = cond1d->next; cond1c; cond1c = cond1c->next )
                {
                    if ( cond1c->op == op_lparen )
                        l_par++;
                    else if ( cond1c->op == op_rparen )
                        l_par--;
                    else if ( cond1c->op == op_or && l_par == 0 )
                    /* Expression too complex - don't touch */
                        return cond1a;
                    else if ( l_par < 0 )
                    {
                        fprintf( stderr, "incorrect condition: programming error ?\n" );
                        exit( 1 );
                    }
                }
                cond1a->op = op_false;
                cond1a->next = NULL;
                free_cond( cond1b );
                return cond1a;
            }
            else if ( (cond1b->op == op_neq && strcmp( cond1c->str, current_arch ))
                 || (cond1b->op == op_eq && ! strcmp( cond1c->str, current_arch )) )
            {
                /* This is for current architecture */
                cond1b = cond1d->next;
                cond1d->next = NULL;
                free_cond( cond1a );
                return eliminate_other_arch( cond1b );
            }
        }
    }
    if ( cond1a->op == op_variable && ! vartable[cond1a->nameindex].defined )
    {
        cond1b = cond1a->next; if ( cond1b == NULL ) goto done;
        cond1c = cond1b->next; if ( cond1c == NULL ) goto done;
        cond1d = cond1c->next;

        if ( cond1c->op == op_constant
        && ( cond1d == NULL || cond1d->op == op_and ) ) /*???*/
        {
            if ( cond1b->op == op_eq && strcmp( cond1c->str, "" ) )
            {
                cond1a->op = op_false;
                cond1a->next = NULL;
                free_cond( cond1b );
                return cond1a;
            }
        }
        else if ( cond1c->op == op_constant && cond1d->op == op_or )
        {
            if ( cond1b->op == op_eq && strcmp( cond1c->str, "" ) )
            {
                cond1b = cond1d->next;
                cond1d->next = NULL;
                free_cond( cond1a );
                return eliminate_other_arch( cond1b );
            }
        }
    }
done:
    return list;
}



/*
 * This is the main transformation function.
 */
void fix_conditionals( struct kconfig * scfg )
{
    struct kconfig * cfg;

    /*
     * Transform op_variable to op_kvariable.
     */
    mark_variables( scfg );

    /*
     * Walk the statement list, maintaining a stack of current conditions.
     *   token_if      push its condition onto the stack.
     *   token_else    invert the condition on the top of the stack.
     *   token_endif   pop the stack.
     *
     * For a simple statement, create a condition chain by joining together
     * all of the conditions on the stack.
     */
    {
        struct condition * cond_stack [32];
        int depth = 0;
        struct kconfig * prev = NULL;

        for ( cfg = scfg; cfg != NULL; cfg = cfg->next )
        {
            int good = 1;
            switch ( cfg->token )
            {
            default:
                break;

            case token_if:
                cond_stack [depth++] =
                    remove_bang( eliminate_other_arch( cfg->cond ) );
                cfg->cond = NULL;
                break;

            case token_else:
                {
                    /*
                     * Invert the condition chain.
                     *
                     * Be careful to transfrom op_or to op_and1, not op_and.
                     * I will need this later in the code that removes
                     * duplicate conditions.
                     */
                    struct condition * cond;

                    for ( cond  = cond_stack [depth-1];
                          cond != NULL;
                          cond  = cond->next )
                    {
                        switch( cond->op )
                        {
                        default:     break;
                        case op_and: cond->op = op_or;   break;
                        case op_or:  cond->op = op_and1; break;
                        case op_neq: cond->op = op_eq;   break;
                        case op_eq:  cond->op = op_neq;  break;
                        case op_true: cond->op = op_false;break;
                        case op_false:cond->op = op_true; break;
                        }
                    }
                }
                break;

            case token_fi:
                --depth;
                break;

            case token_bool:
            case token_choice_item:
            case token_choice_header:
            case token_comment:
            case token_define_bool:
            case token_define_hex:
            case token_define_int:
            case token_define_string:
            case token_define_tristate:
            case token_endmenu:
            case token_hex:
            case token_int:
            case token_mainmenu_option:
            case token_string:
            case token_tristate:
            case token_unset:
                cfg->cond = join_condition_stack( cond_stack, depth );
                if ( cfg->cond && cfg->cond->op == op_false )
                {
                    good = 0;
                    if ( prev )
                        prev->next = cfg->next;
                    else
                        scfg = cfg->next;
                }
                break;

            case token_dep_bool:
            case token_dep_mbool:
            case token_dep_tristate:
                /*
                 * Same as the other simple statements, plus an additional
                 * condition for the dependency.
                 */
                if ( cfg->cond )
                {
                    cond_stack [depth] = eliminate_other_arch( cfg->cond );
                    cfg->cond = join_condition_stack( cond_stack, depth+1 );
                }
                else
                {
                    cfg->cond = join_condition_stack( cond_stack, depth );
                }
                if ( cfg->cond && cfg->cond->op == op_false )
                {
                    good = 0;
                    if ( prev )
                        prev->next = cfg->next;
                    else
                        scfg = cfg->next;
                }
                break;
            }
            if ( good )
                prev = cfg;
        }
    }
}



#if 0
void dump_condition( struct condition *list )
{
    struct condition *tmp;
    for ( tmp = list; tmp; tmp = tmp->next )
    {
        switch (tmp->op)
        {
        default:
            break;
        case op_variable:
            printf( " %s", vartable[tmp->nameindex].name );
            break;
        case op_constant: 
            printf( " %s", tmp->str );
            break;
        case op_eq:
            printf( " =" );
            break;
        case op_bang:
            printf( " !" );
            break;
        case op_neq:
            printf( " !=" );
            break;
        case op_and:
        case op_and1:
            printf( " -a" );
            break;
        case op_or:
            printf( " -o" );
            break;
        case op_true:
            printf( " TRUE" );
            break;
        case op_false:
            printf( " FALSE" );
            break;
        case op_lparen:
            printf( " (" );
            break;
        case op_rparen:
            printf( " )" );
            break;
        }
    }
    printf( "\n" );
}
#endif