//
//  TLFunc.m
//  TinyLisp
//
//  Created by David Phillip Oster on 9/2/07.
//
//  Copyright 2007 David Phillip Oster

//     Licensed under the Apache License, Version 2.0 (the "License");
//     you may not use this file except in compliance with the License.
//     You may obtain a copy of the License at

//         http://www.apache.org/licenses/LICENSE-2.0

//     Unless required by applicable law or agreed to in writing, software
//     distributed under the License is distributed on an "AS IS" BASIS,
//     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//     See the License for the specific language governing permissions and
//     limitations under the License.
#import "TLLisp.h"

@interface TLFuncAbstract(PrivateMethods)
+ (TLID *)tlApplyInner:(NSArray *)arg;
+ (NSArray *)evaluateArgs:(NSArray *)call fromIndex:(int)index;
@end
@implementation TLFuncAbstract(PrivateMethods)
+ (TLID *)tlApplyInner:(NSArray *)arg {
  return nil;
}

+ (NSArray *)evaluateArgs:(NSArray *)call fromIndex:(int)index{
  NSMutableArray *result = [NSMutableArray array];
  int i, iCount = [call count];
  for (i = 0;i < index; ++i) {
    [result addObject:[call objectAtIndex:i]]; // already evaluated
  }
  for (;i < iCount; ++i) {
    TLID *val = [[call objectAtIndex:i] tlEval];
    if (nil == val) {
      val = [NSNull null];
    }
    [result addObject:val];
  }
  return result;
}
@end

@implementation TLFuncAbstract
+ (TLID *)tlApply:(NSArray *)arg {
  return [self tlApplyInner:[self evaluateArgs:arg]];
}

// abstract class just returns args. TLFunc evaluates. 
// This makes defining special funcs easy.
+ (NSArray *)evaluateArgs:(NSArray *)call {
  return call;
}

+ (BOOL)isLambdaCall:(TLID *)first withArray:(NSArray *)call {
  return [first isKindOfClass:[NSArray class]] && 
    3 <= [(NSArray *)first count] && 
    gTLLambda == [(NSArray *)first objectAtIndex:0];
}

+ (TLID *)performLambdaCall:(TLID *)first withArray:(NSArray *)call {
  NSArray *args = [self evaluateArgs:call];
  NSArray *formals = [(NSArray *)first objectAtIndex:1];
  TLID *token = TLBind(formals, args);

  TLID *val = nil;
  int i, iCount = [(NSArray *)first count];
  // the lambda expression starts with a lambda, and a formals list.
  for (i = 2;i < iCount; ++i) {
    val = [[(NSArray *)first objectAtIndex:i] tlEval];
  }

  TLUnbind(token);
  return val;
}

+ (BOOL)isObjectiveCCall:(TLID *)first withArray:(NSArray *)call {
//TODO not yet
  return NO;
}

+ (TLID *)performObjectiveCCall:(TLID *)first withArray:(NSArray *)call {
//TODO not yet
  return nil;
}

@end

// inherit from this, is you can't have arguments pre-evaluated. 
@implementation TLFuncSpecial
+ (NSArray *)evaluateArgs:(NSArray *)call {
  return call;
}
@end

@implementation TLFunc
+ (NSArray *)evaluateArgs:(NSArray *)call {
  return [self evaluateArgs:call fromIndex:1];
}
@end


@implementation TLFuncprogn
+ (TLID *)tlApplyInner:(NSArray *)args {
  return [args lastObject];
}
@end

@implementation TLFuncprog0
+ (TLID *)tlApplyInner:(NSArray *)args {
  return [args objectAtIndex:1];
}
@end

@implementation TLFuncquote
+ (TLID *)tlApplyInner:(NSArray *)call {
  return [call objectAtIndex:1];
}
@end

@implementation TLFuncset
+ (TLID *)tlApplyInner:(NSArray *)args {
  TLID *val = nil;
  int i, iCount = [args count];
  for(i = 1; i < iCount; i += 2) {
    TLAtom *atom = [args objectAtIndex:i];
    val = [args objectAtIndex:i+1];
    [atom setValue:val];
  }
  return val;
}
@end

@implementation TLFuncClassFromString
+ (TLID *)tlApplyInner:(NSArray *)args {
  TLID *atomSelf = [args objectAtIndex:1];
  return (TLID *) NSClassFromString((NSString *)atomSelf);
}
@end

@implementation TLFuncPerformSelector
+ (TLID *)tlApplyInner:(NSArray *)args {
  TLID *atomSelf = [args objectAtIndex:1];
  TLID *atomSelector = [args objectAtIndex:2];
  int i, iCount = [args count];
  SEL sel = NSSelectorFromString((NSString *)atomSelector);
  NSMethodSignature *sig = [atomSelf methodSignatureForSelector:sel];
  if (nil == sig) {
    return nil;
  }
  NSInvocation *voke = [NSInvocation invocationWithMethodSignature:sig];
  [voke setTarget:atomSelf];
  [voke setSelector:sel];
  for(i = 3;i < iCount; ++i){
    const char *argType = [sig getArgumentTypeAtIndex:i-1];
    if (0 == strcmp(argType, "I") || 0 == strcmp(argType, "i")) {
      NSNumber *num = [args objectAtIndex:i];
      int n = [num intValue];
      [voke setArgument:&n atIndex:i-1];
    } else {
      TLID *arg = [args objectAtIndex:i];
      [voke setArgument:&arg atIndex:i-1];
    }
  }
  [voke invoke];
  unsigned int length = [sig methodReturnLength];
  if (length == sizeof(TLID*)) {
    TLID *result;
    [voke getReturnValue:&result];
    const char *resultType = [sig methodReturnType];
    if (0 == strcmp(resultType, "I") || 0 == strcmp(resultType, "i")) {
      return [NSNumber numberWithInt:(int)result];
    }
    return result;
  }
// possibly other cases here.
  return nil;
}
@end


@implementation TLFunctlIf
+ (TLID *)tlApplyInner:(NSArray *)call {  
  TLID *val = [[call objectAtIndex:1] tlEval];
  if (nil == val || [val isEqual:[NSNull null]]) {
    if (4 == [call count]) {
      return [[call objectAtIndex:3] tlEval];
    }
    return nil;
  } else {
    return [[call objectAtIndex:2] tlEval];
  }
}
@end

@implementation TLFunctlWhile
+ (TLID *)tlApplyInner:(NSArray *)call {
  TLID *result = nil;
  for(;;){
    TLID *val = [[call objectAtIndex:1] tlEval];
    if (nil == val || [val isEqual:[NSNull null]]) {
      break;  // <-- normal loop exit
    }
    result = [self evaluateArgs:call fromIndex:2];
    result = [(NSArray *)result lastObject];
  }
  return result;
}
@end

@implementation TLFunctlAnd
+ (TLID *)tlApplyInner:(NSArray *)call {
  TLID *result = nil;
  int i, iCount = [call count];
  for(i = 1;i < iCount;++i){
    result = [[call objectAtIndex:i] tlEval];
    if (nil == result || [result isEqual:[NSNull null]]) {
      break;  // <-- normal loop exit
    }
  }
  return result;
}
@end

@implementation TLFunctlOr
+ (TLID *)tlApplyInner:(NSArray *)call {
  TLID *result = nil;
  int i, iCount = [call count];
  for(i = 1;i < iCount;++i){
    result = [[call objectAtIndex:i] tlEval];
    if ( ! (nil == result || [result isEqual:[NSNull null]])) {
      break;  // <-- normal loop exit
    }
  }
  return result;
}
@end

@implementation TLFunceq
+ (TLID *)tlApplyInner:(NSArray *)args {
  BOOL isEqual = YES;
  int i, iCount = [args count];
  if (1 < iCount) {
    TLID *first = [args objectAtIndex:1];
    for (i = 2; isEqual && i < iCount; ++i) {
      if ( ! [first isEqual:[args objectAtIndex:i]]) {
        isEqual = NO;
      }
    }
  }
  return isEqual ? gTLT : nil;
}
@end


@implementation TLFuncplus
+ (TLID *)tlApplyInner:(NSArray *)args {
  double n = 0;
  int i, iCount = [args count];
  for (i = 1; i < iCount; ++i) {
    n += [[args objectAtIndex:i] floatValue];
  }
  return [NSNumber numberWithDouble:n];
}
@end

@implementation TLFuncminus
+ (TLID *)tlApplyInner:(NSArray *)args {
  double n = 0;
  if (2 == [args count]) {
    n = - [[args objectAtIndex:1] floatValue];
  } else {
    n = [[args objectAtIndex:1] floatValue] - [[args objectAtIndex:2] floatValue];
  }
  return [NSNumber numberWithDouble:n];
}
@end

@implementation TLFunctimes
+ (TLID *)tlApplyInner:(NSArray *)args {
  double n = 1.;
  int i, iCount = [args count];
  for (i = 1; i < iCount; ++i) {
    n *= [[args objectAtIndex:i] floatValue];
  }
  return [NSNumber numberWithDouble:n];
}
@end

@implementation TLFuncdivide
+ (TLID *)tlApplyInner:(NSArray *)args {
  double n = 0;
  if (2 == [args count]) {
    n = 1. / [[args objectAtIndex:1] floatValue];
  } else {
    n = [[args objectAtIndex:1] floatValue] / [[args objectAtIndex:2] floatValue];
  }
  return [NSNumber numberWithDouble:n];
}
@end

@implementation TLFuncgt
+ (TLID *)tlApplyInner:(NSArray *)args {
  BOOL val = YES;
  float n0 = [[args objectAtIndex:1] floatValue];
  int i, iCount = [args count];
  for (i = 2;i < iCount;++i){
    float n1 = [[args objectAtIndex:i] floatValue];
    if (n0 > n1) {
      n0 = n1;
    } else {
      val = NO;
      break;
    }
  }
  return val ? gTLT : nil;
}
@end


@implementation TLFunclt
+ (TLID *)tlApplyInner:(NSArray *)args {
  BOOL val = YES;
  int i, iCount = [args count];
  float n0 = [[args objectAtIndex:1] floatValue];
  for (i = 2;i < iCount;++i){
    float n1 = [[args objectAtIndex:i] floatValue];
    if (n0 < n1) {
      n0 = n1;
    } else {
      val = NO;
      break;
    }
  }
  return val ? gTLT : nil;
}
@end


@implementation TLFuncge
+ (TLID *)tlApplyInner:(NSArray *)args {
  BOOL val = YES;
  int i, iCount = [args count];
  float n0 = [[args objectAtIndex:1] floatValue];
  for (i = 2;i < iCount;++i){
    float n1 = [[args objectAtIndex:i] floatValue];
    if (n0 >= n1) {
      n0 = n1;
    } else {
      val = NO;
      break;
    }
  }
  return val ? gTLT : nil;
}
@end


@implementation TLFuncle
+ (TLID *)tlApplyInner:(NSArray *)args {
  BOOL val = YES;
  int i, iCount = [args count];
  float n0 = [[args objectAtIndex:1] floatValue];
  for (i = 2;i < iCount;++i){
    float n1 = [[args objectAtIndex:i] floatValue];
    if (n0 <= n1) {
      n0 = n1;
    } else {
      val = NO;
      break;
    }
  }
  return val ? gTLT : nil;
}
@end

@implementation TLFuncprint
+ (TLID *)tlApplyInner:(NSArray *)args {
  int i, iCount = [args count];
  NSMutableString *outS = [NSMutableString string];
  TLID *val = nil;
  for (i = 1;i < iCount;++i){
    val = [args objectAtIndex:i];
    [val tlPrint:outS];
  }
  printf("%s\n", [outS UTF8String]);
  return val;
}
@end

@implementation TLFunccount
+ (TLID *)tlApplyInner:(NSArray *)args {
  TLID *val = [args objectAtIndex:1];
  int n = 0;
  if ([val respondsToSelector:@selector(count)]) {
    n = (int) [val performSelector:@selector(count)];
  } else if([val respondsToSelector:@selector(length)]) {
    n = (int) [val performSelector:@selector(length)];
  }
  return [NSNumber numberWithInt:n];
}
@end

// (list 2 3 4) returns (2 3 4)
@implementation TLFunclist
+ (TLID *)tlApplyInner:(NSArray *)args {
  NSMutableArray *result = [[args mutableCopy] autorelease];
  [result removeObjectAtIndex:0];
  return result;
}
@end

// objectAtIndex = at
@implementation TLFuncAtIndex
+ (TLID *)tlApplyInner:(NSArray *)args {
  TLID *arry = [args objectAtIndex:1];
  TLID *num = [args objectAtIndex:2];
  if ([arry respondsToSelector:@selector(objectAtIndex:)]) {
    return [(NSArray *)arry objectAtIndex:[(NSNumber *)num intValue]];
  } else if ([arry respondsToSelector:@selector(characterAtIndex:)]) {
    return [NSNumber numberWithInt:[(NSString *)arry characterAtIndex:[(NSNumber *)num intValue]]];
  }
  return nil;
}
@end

// insertAtIndex
@implementation TLFuncInsertAtIndex
+ (TLID *)tlApplyInner:(NSArray *)args {
  NSMutableArray *arry = (NSMutableArray *) [args objectAtIndex:1];
  TLID *newObj = [args objectAtIndex:2];
  NSNumber *num = (NSNumber *) [args objectAtIndex:3];
  if ([arry respondsToSelector:@selector(insertObject:atIndex:)]) {
    [arry insertObject:newObj atIndex:[num intValue]];
  } else if ([arry respondsToSelector:@selector(insertString:atIndex:)]) {
    NSString *s = nil;
    if ([newObj isKindOfClass:[NSString class]]) {
      s = (NSString *) newObj;
    } else if ([newObj respondsToSelector:@selector(intValue)]) {
      unichar c = [(NSNumber *)newObj intValue];
      s = [[[NSString alloc] initWithCharacters:&c length:1] autorelease];
    }
    if (s) {
      [(NSMutableString *)arry insertString:s atIndex:[num intValue]];
    }
  }
  return nil;
}
@end

// removeAtIndex
@implementation TLFuncRemoveAtIndex
+ (TLID *)tlApplyInner:(NSArray *)args {
  NSMutableArray *arry = (NSMutableArray *) [args objectAtIndex:1];
  NSNumber *num = (NSNumber *) [args objectAtIndex:2];
  if ([arry respondsToSelector:@selector(removeObjectAtIndex:)]) {
    [arry removeObjectAtIndex:[num intValue]];
  } else if ([arry respondsToSelector:@selector(deleteCharactersInRange:)]) {
    [(NSMutableString *)arry deleteCharactersInRange:NSMakeRange([num intValue], 1)];
  }
  return nil;
}
@end

// replaceAtIndex
@implementation TLFuncReplaceAtIndexWith
+ (TLID *)tlApplyInner:(NSArray *)args {
  NSMutableArray *arry = (NSMutableArray *) [args objectAtIndex:1];
  NSNumber *num = (NSNumber *) [args objectAtIndex:2];
  TLID *newObj = [args objectAtIndex:3];
  if ([arry respondsToSelector:@selector(replaceObjectAtIndex:withObject:)]) {
    [arry replaceObjectAtIndex:[num intValue] withObject:newObj];
  } else if ([arry respondsToSelector:@selector(replaceCharactersInRange:withString:)]) {
    NSString *s = nil;
    if ([newObj isKindOfClass:[NSString class]]) {
      s = (NSString *) newObj;
    } else if ([newObj respondsToSelector:@selector(intValue)]) {
      unichar c = [(NSNumber *)newObj intValue];
      s = [[[NSString alloc] initWithCharacters:&c length:1] autorelease];
    }
    if (s) {
      [(NSMutableString *)arry replaceCharactersInRange:NSMakeRange([num intValue], 1) withString:s];
    }
  }
  return nil;
}
@end

// (propertyForKey 'a "foo")
@implementation TLFuncPropertyForKey
+ (TLID *)tlApplyInner:(NSArray *)args {
  TLAtom  *atom = (TLAtom *) [args objectAtIndex:1];
  NSString *key = [args objectAtIndex:2];
  return [atom propertyForKey:key];
}
@end

// (removePropertyForKey 'a "foo")
@implementation TLFuncRemovePropertyForKey
+ (TLID *)tlApplyInner:(NSArray *)args {
  TLAtom  *atom = (TLAtom *) [args objectAtIndex:1];
  NSString *key = [args objectAtIndex:2];
  [atom removePropertyForKey:key];
  return nil;
}
@end

// (setPropertyForKey 'a 5 "foo")
@implementation TLFuncSetPropertyForKey
+ (TLID *)tlApplyInner:(NSArray *)args {
  TLAtom  *atom = (TLAtom *) [args objectAtIndex:1];
  TLID *val = [args objectAtIndex:2];
  [atom setProperty:val forKey:[args objectAtIndex:3]];
  return val;
}
@end

// (propertyKeys 'a)
@implementation TLFuncPropertyKeys
+ (TLID *)tlApplyInner:(NSArray *)args {
  TLAtom  *atom = (TLAtom *) [args objectAtIndex:1];
  return [atom propertyKeys];
}
@end