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/*
 *  R.app : a Cocoa front end to: "R A Computer Language for Statistical Data Analysis"
 *  
 *  R.app Copyright notes:
 *                     Copyright (C) 2004-5  The R Foundation
 *                     written by Stefano M. Iacus and Simon Urbanek
 *
 *                  
 *  R Copyright notes:
 *                     Copyright (C) 1995-1996   Robert Gentleman and Ross Ihaka
 *                     Copyright (C) 1998-2001   The R Development Core Team
 *                     Copyright (C) 2002-2004   The R Foundation
 *
 *  This program 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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.
 *
 *  A copy of the GNU General Public License is available via WWW at
 *  http://www.gnu.org/copyleft/gpl.html.  You can also obtain it by
 *  writing to the Free Software Foundation, Inc., 59 Temple Place,
 *  Suite 330, Boston, MA  02111-1307  USA.
 */

#import "CodeCompletion.h"
#import "../REngine/REngine.h"
#import "../RegexKitLite.h"
#import "FileCompletion.h"
#import "RGUI.h"
#import "../RController.h"


@implementation CodeCompletion

+ (NSString*) complete: (NSString*) part {
    if (preventReentrance && insideR>0) {
        SLog(@"CodeCompletion.complete: returning nil completion to prevent R re-entrance [***]");
        return nil;
    }
    REngine *re = [REngine mainEngine];
    if (![re beginProtected]) {
        SLog(@"CodeCompletion.complete: returning nil completion because protected REngine entry failed [***]");
        return nil;
    }
    // first get the length of the search path so we can go environment by environment
    RSEXP *x = [re evaluateString:@"length(search())"];
    int pos=1, maxpos;
    if (x==nil || ((maxpos = [x integer])==0)) { [re endProtected]; return nil; }

    // ok, we got the search path length; search in each environment and if something matches, get it, otherwise go to the next one
    while (pos<=maxpos) {
        // use ls to get the names of the objects in the specific environment
        NSString *ls=[NSString stringWithFormat:@"ls(pos=%d, all.names=TRUE, pattern=\"^%@.*\")", pos, part];
        RSEXP *x = [re evaluateString:ls];
        //NSLog(@"attepmting to find %@ via %@", part, ls);
        if (x==nil) {
            [re endProtected];
            return nil;
        }
        NSArray *a = [x array];
        if (a == nil) {
            [x release];
            [re endProtected];
            return nil;
        }
        
        { // the following code works also if pattern is not specified; with pattern present we could make it even easier, but currently we use it just to narrow the search (e.g. "." could still be matched by something else ...)
            int i=0, matches=0;
            NSString *common=nil;
            while (i<[a count]) {
                NSString *sx = (NSString*) [a objectAtIndex:i];
                if ([sx hasPrefix: part]) {
                    if (matches==0)
                        common = [[NSString alloc] initWithString: sx];
                    else {
                        NSString *cpref=[[NSString alloc] initWithString:[common commonPrefixWithString:sx options:0]];
                        [common release];
                        common = cpref;
                    }
                    matches++;
                }
                i++;
            }
            if (common) { // attempt to get class of the object - it will fail if that's just a partial object, but who cares..
                    x = [re evaluateString:[NSString stringWithFormat:@"try(class(%@),silent=TRUE)",common]];
                    [re endProtected];
                if (x && [x string] && [[x string] isEqualToString:@"function"])
                    return [[common autorelease] stringByAppendingString:@"("];
                else
                    return [common autorelease];
            }
        }
        pos++;
    }
    [re endProtected];
    return nil;
}

+ (NSArray*) completeAll: (NSString*) part cutPrefix: (int) prefix {
    if (preventReentrance && insideR>0) {
        SLog(@"CodeCompletion.completeAll: returning nil completion to prevent R re-entrance [***]");
        return nil;
    }
    
    REngine *re = [REngine mainEngine];
    if (![re beginProtected]) {
        SLog(@"CodeCompletion.completeAll: returning nil completion because protected REngine entry failed [***]");
        return nil;
    }
    
    // first get the length of the search path so we can go environment by environment
    RSEXP *x = [re evaluateString:@"length(search())"];
    int pos=1, maxpos, matches=0;
    NSMutableArray *ca = nil;
    NSString *common=nil;

    if (x==nil || ((maxpos = [x integer])==0)) { [re endProtected]; return nil; }
    
    ca = [[NSMutableArray alloc] initWithCapacity: 8];
    
    // ok, we got the search path length; search in each environment and if something matches, get it, otherwise go to the next one
    while (pos<=maxpos) {
        // use ls to get the names of the objects in the specific environment
        NSString *ls=[NSString stringWithFormat:@"ls(pos=%d, all.names=TRUE, pattern=\"^%@.*\")", pos, part];
        RSEXP *x = [re evaluateString:ls];
        //NSLog(@"attepmting to find %@ via %@", part, ls);
        if (x==nil) {
            [re endProtected];
            return nil;
        }
        
        NSArray *a = [x array];
        
        if (a == nil) {
            [x release];
            [re endProtected];
            return nil;
        }
        
        { // the following code works also if pattern is not specified; with pattern present we could make it even easier, but currently we use it just to narrow the search (e.g. "." could still be matched by something else ...)
            int i=0, firstMatch=-1;
            while (i<[a count]) {
                NSString *sx = (NSString*) [a objectAtIndex:i];
                if ([sx hasPrefix: part]) {
                    if (matches==0) {
                        firstMatch=i;
                        common=[[NSString alloc] initWithString: sx];
                    } else {
                        NSString *cpref=[[NSString alloc] initWithString:[common commonPrefixWithString:sx options:0]];
                        [common release];
                        common=cpref;
                    }
                    if (prefix<[sx length]) {
                        [ca addObject: [sx substringFromIndex:prefix]];
                        matches++;
                    }
                }
                i++;
            }
        }
        pos++;
    }
    if (common) { 
        if (matches==1) {
            // attempt to get class of the object - it will fail if that's just a partial object, but who cares..
            x = [re evaluateString:[NSString stringWithFormat:@"try(class(%@),silent=TRUE)",common]];
            [ca release];
            if (x!=nil && [x string]!=nil && [[x string] isEqualToString:@"function"]) {
                [re endProtected];
                return [NSArray arrayWithObject: [[[common autorelease] stringByAppendingString:@"("] substringFromIndex:prefix]];
            } else {
                [re endProtected];
                return [NSArray arrayWithObject: [[common autorelease] substringFromIndex:prefix]];
            }
        } else {
            [common release];
            [re endProtected];
            return ca;
        }
    }
    [re endProtected];
    [ca release];
    return nil;
}

+ (NSArray*) retrieveSuggestionsForScopeRange:(NSRange)scopeRange inTextView:(NSTextView*)textView
{

    if (preventReentrance && insideR>0) {
        SLog(@"CodeCompletion.retrieveSuggestionForScope: returning nil completion to prevent R re-entrance [***]");
        return nil;
    }

    REngine *re = [REngine mainEngine];
    if (![re beginProtected]) {
        SLog(@"CodeCompletion.retrieveSuggestionForScope: returning nil completion because protected REngine entry failed [***]");
        return nil;
    }

    NSString *linebuffer = [[[textView textStorage] string] substringWithRange:scopeRange];

    SLog(@" - passed string for completion:\n%@", [linebuffer description]);
    if(!linebuffer || ![linebuffer length]) {
        [re endProtected];
        return nil;
    }

    // convert scope string to single line
    linebuffer = [linebuffer stringByReplacingOccurrencesOfRegex:@"[\n\r\t]+" withString:@" "];

    // first we need to find out whether we're in a text part or code part
    unichar c;
    int tl = [linebuffer length], tp=0, quotes=0, dquotes=0, lastQuote=-1;
    while (tp < tl) {
        c = CFStringGetCharacterAtIndex((CFStringRef)linebuffer, tp);
        if (c=='\\') 
            tp++; // skip the next char after a backslash (we don't have to worry about \023 and friends)
        else {
            if (dquotes==0 && c=='\'') {
                quotes^=1;
                if (quotes) lastQuote=tp;
            }
            if (quotes==0 && c=='"') {
                dquotes^=1;
                if (dquotes) lastQuote=tp;
            }
        }
        tp++;
    }

    // if we're inside any quotes, bail via file completion
    if (quotes+dquotes>0) {
        SLog(@" - cursor is inside quotes - call file completion");
        [re endProtected];
        return [FileCompletion completeAll:[linebuffer substringFromIndex:lastQuote+1] cutPrefix:0];
    }

    // use internal rcompgen to retrieve completion suggestions;
    // can be modified by the user via rc.setting s() and rc.options() resp.

    // escape ' since we pass it via @" '...' "
    linebuffer = [linebuffer stringByReplacingOccurrencesOfString:@"'" withString:@"\\'"];
    SLog(@" - rcompgen completion will be invoked with:\n%@", linebuffer);
    RSEXP *xx = [re evaluateString:[NSString stringWithFormat:@"rcompgen.completion('%@')", linebuffer]];
    [re endProtected];
    if(xx) {

        NSArray *ca = [xx array];

        // if only one suggestion was found set function hint in status bar
        if (ca && [ca count]==1) {

            NSString *foundItem = [ca objectAtIndex:0];

            // ignore all spaces, equal signs, and opened paranthesis at the end
            BOOL showIt = YES;
            int i = [foundItem length]-1;
            unichar c;
            while(i>0) {
                c = CFStringGetCharacterAtIndex((CFStringRef)foundItem, i);
                if(c == ' ' || c == '(') {
                    i--;
                }
                else if (c == '=') {
                    // if suggestion ends with a = do not show the hint, since
                    // it's a parameter
                    showIt = NO;
                    break;
                }
                else
                    break;
            }
            i++;
            foundItem = [foundItem substringToIndex:i];
            SLog(@" - show function hint '%@' with display %d", foundItem, showIt);
            if(showIt && [[(NSTextView*)[[NSApp keyWindow] firstResponder] delegate] respondsToSelector:@selector(hintForFunction:)])
                // (RController*) is only a dummy to avoid compiler warnings
                [(RController*)[(NSTextView*)[[NSApp keyWindow] firstResponder] delegate] hintForFunction:foundItem];
        }

        SLog(@" - found %d suggestions", [ca count]);
        [xx release];
        return (ca && [ca count]) ? ca : nil;

    }

    return nil;

}

@end