//
//  MPExpressionTests.m
//  MathPad
//
//  Created by Kim Wittenburg on 19.04.14.
//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
//

#import <XCTest/XCTest.h>

#import "MPExpression.h"
#import "MPFunction.h"

@interface MPExpressionTests : XCTestCase

@end

@implementation MPExpressionTests

- (void)testInitialization {
    MPExpression *emptyExpression = [[MPExpression alloc] init];
    MPExpression *stringExpression = [[MPExpression alloc] initWithString:@"1234+5678"];
    MPExpression *functionExpression = [[MPExpression alloc] initWithFunction:[[MPFunction alloc] init]];
    MPExpression *complexExpression = [[MPExpression alloc] initWithSymbols:@[@"1234", [[MPFunction alloc] init], @"17", [[MPFunction alloc] init]]];
    
    XCTAssertEqual([emptyExpression numberOfSymbols], 0);
    XCTAssertEqual([stringExpression numberOfSymbols], 1);
    XCTAssertEqual([functionExpression numberOfSymbols], 1);
    XCTAssertEqual([complexExpression numberOfSymbols], 4);
    
    XCTAssertEqualObjects([stringExpression symbolAtIndex:0], @"1234+5678");
    XCTAssertEqualObjects([functionExpression symbolAtIndex:0], [[MPFunction alloc] init]);
    XCTAssertEqualObjects([complexExpression symbolAtIndex:2], @"17");
}

- (void)testSubexpressions {
    MPExpression *testExpression = [MPExpression expressionWithSymbols:@[@"1234", [[MPFunction alloc] init], @"17", [[MPFunction alloc] init]]];
    
    /********** subexpressionFromIndex: **********/
    // Test with start index at front
    MPExpression *subexpression = [testExpression subexpressionFromIndex:0];
    XCTAssertEqual([subexpression numberOfSymbols], 4);
    XCTAssertEqualObjects([subexpression symbolAtIndex:0], @"1234");
    
    // Test with start index in first symbol
    subexpression = [testExpression subexpressionFromIndex:2];
    XCTAssertEqual([subexpression numberOfSymbols], 4);
    XCTAssertEqualObjects([subexpression symbolAtIndex:0], @"34");
    
    // Test with start index in middle symbol starting with a literal
    subexpression = [testExpression subexpressionFromIndex:6];
    XCTAssertEqual([subexpression numberOfSymbols], 2);
    XCTAssertEqualObjects([subexpression symbolAtIndex:0], @"7");
    
    // Test with start index in middle symbol starting with a function
    subexpression = [testExpression subexpressionFromIndex:4];
    XCTAssertEqual([subexpression numberOfSymbols], 3);
    XCTAssertEqualObjects([subexpression symbolAtIndex:0], [[MPFunction alloc] init]);
    
    // Test with start index in last symbol
    subexpression = [testExpression subexpressionFromIndex:7];
    XCTAssertEqual([subexpression numberOfSymbols], 1);
    XCTAssertEqualObjects([subexpression symbolAtIndex:0], [[MPFunction alloc] init]);
    
    // Test with start index at end
    subexpression = [testExpression subexpressionFromIndex:8];
    XCTAssertEqual([subexpression numberOfSymbols], 0);
    
    /********** subexpressionToIndex: **********/
    // Test with end index at front
    subexpression = [testExpression subexpressionToIndex:0];
    XCTAssertEqual([subexpression numberOfSymbols], 0);

    // Test with end index in first symbol
    subexpression = [testExpression subexpressionToIndex:2];
    XCTAssertEqual([subexpression numberOfSymbols], 1);
    XCTAssertEqualObjects([subexpression symbolAtIndex:0], @"12");
    
    // Test with end index in middle symbol ending with a literal
    subexpression = [testExpression subexpressionToIndex:6];
    XCTAssertEqual([subexpression numberOfSymbols], 3);
    XCTAssertEqualObjects([subexpression symbolAtIndex:2], @"1");
    
    // Test with end index in middle symbol ending with a function
    subexpression = [testExpression subexpressionToIndex:5];
    XCTAssertEqual([subexpression numberOfSymbols], 2);
    XCTAssertEqualObjects([subexpression symbolAtIndex:1], [[MPFunction alloc] init]);
    
    // Test with end index at end
    subexpression = [testExpression subexpressionToIndex:8];
    XCTAssertEqual([subexpression numberOfSymbols], 4);
    XCTAssertEqualObjects([subexpression symbolAtIndex:3], [[MPFunction alloc] init]);
    
    /********** subexpressionWithRange: **********/
    // Test with empty range
    subexpression = [testExpression subexpressionWithRange:NSMakeRange(4, 0)];
    XCTAssertEqual([subexpression numberOfSymbols], 0);
    
    // Test with start and end in first symbol
    subexpression = [testExpression subexpressionWithRange:NSMakeRange(1, 2)];
    XCTAssertEqual([subexpression numberOfSymbols], 1);
    XCTAssertEqualObjects([subexpression symbolAtIndex:0], @"23");
    
    // Test with start in first and end in middle after function
    subexpression = [testExpression subexpressionWithRange:NSMakeRange(2, 3)];
    XCTAssertEqual([subexpression numberOfSymbols], 2);
    XCTAssertEqualObjects([subexpression symbolAtIndex:0], @"34");
    XCTAssertEqualObjects([subexpression symbolAtIndex:1], [[MPFunction alloc] init]);
    
    // Test with start in first and end in middle after literal
    subexpression = [testExpression subexpressionWithRange:NSMakeRange(2, 4)];
    XCTAssertEqual([subexpression numberOfSymbols], 3);
    XCTAssertEqualObjects([subexpression symbolAtIndex:0], @"34");
    XCTAssertEqualObjects([subexpression symbolAtIndex:2], @"1");
}

- (void)testSubexpressionsIllegalRange {
    MPExpression *testExpression = [MPExpression expressionWithSymbols:@[@"1234", [[MPFunction alloc] init], @"17", [[MPFunction alloc] init]]];
    
    // Test with start index beyond end
    @try {
        [testExpression subexpressionFromIndex:10];
        XCTFail(@"Should have raised an exception.");
    }
    @catch (NSException *exception) {}

    // Test with range extending bounds
    @try {
        [testExpression subexpressionWithRange:NSMakeRange(5, 10)];
        XCTFail(@"Should have raised an exception.");
    }
    @catch (NSException *exception) {}
}

- (void)testEqualExpressions {
    MPExpression *expression1 = [[MPExpression alloc] initWithString:@"123"];
    MPExpression *expression2 = [[MPExpression alloc] initWithString:@"1234"];
    MPExpression *expression3 = [[MPExpression alloc] initWithFunction:[[MPFunction alloc] init]];
    MPExpression *expression4 = [[MPExpression alloc] initWithSymbols:@[[[MPFunction alloc] init], @"123"]];
    MPExpression *expression5 = [[MPExpression alloc] initWithSymbols:@[[[MPFunction alloc] init], @"123"]];
    
    XCTAssertNotEqualObjects(expression1, expression2);
    XCTAssertNotEqualObjects(expression1, expression3);
    XCTAssertNotEqualObjects(expression1, expression4);
    XCTAssertNotEqualObjects(expression3, expression4);
    XCTAssertEqualObjects(expression4, expression5);
}

- (void)testAppendSymbols {
    MPExpression *expression1 = [[MPExpression alloc] initWithString:@"123"];
    MPExpression *expression2 = [expression1 expressionByAppendingFunction:[[MPFunction alloc] init]];
    MPExpression *expression3 = [[MPExpression alloc] initWithSymbols:@[@"123", [[MPFunction alloc] init]]];
    
    XCTAssertEqualObjects(expression2, expression3);
}

- (void)testDescription {
    // Test Simple Expressions
    MPExpression *testExpression = [[MPExpression alloc] initWithString:@"1234"];
    XCTAssertEqualObjects([testExpression description], @"1234");
    
    testExpression = [[MPExpression alloc] initWithFunction:[[MPFunction alloc] init]];
    XCTAssertEqualObjects([testExpression description], @"[]");
    
    // Test function after literal without explicit operator
    testExpression = [[MPExpression alloc] initWithSymbols:@[@"123", [[MPFunction alloc] init]]];
    XCTAssertEqualObjects([testExpression description], @"123*[]");
    
    // Test function after literal with explicit operator
    testExpression = [[MPExpression alloc] initWithSymbols:@[@"123+", [[MPFunction alloc] init]]];
    XCTAssertEqualObjects([testExpression description], @"123+[]");
    
    // Test literal after function without explicit operator
    testExpression = [[MPExpression alloc] initWithSymbols:@[[[MPFunction alloc] init], @"123"]];
    XCTAssertEqualObjects([testExpression description], @"[]*123");
    
    // Test literal after function with explicit operator
    testExpression = [[MPExpression alloc] initWithSymbols:@[[[MPFunction alloc] init], @"-123"]];
    XCTAssertEqualObjects([testExpression description], @"[]-123");
    
    // Test function after function without explicit operator
    testExpression = [[MPExpression alloc] initWithSymbols:@[[[MPFunction alloc] init], [[MPFunction alloc] init]]];
    XCTAssertEqualObjects([testExpression description], @"[]*[]");
    
    // Test function after function with explicit operator
    testExpression = [[MPExpression alloc] initWithSymbols:@[[[MPFunction alloc] init], @"-", [[MPFunction alloc] init]]];
    XCTAssertEqualObjects([testExpression description], @"[]-[]");
    
    
    // Test whitespaces in literal
    testExpression = [[MPExpression alloc] initWithSymbols:@[@" 123 + ", [[MPFunction alloc] init]]];
    XCTAssertEqualObjects([testExpression description], @"123 +[]");
}

- (void)testCopying {
    MPExpression *baseExpression = [[MPExpression alloc] initWithFunction:[[MPFunction alloc] init]];
    MPExpression *copy = [baseExpression copy];
    
    XCTAssertNotEqual(copy, baseExpression);
    XCTAssertNotEqual([baseExpression symbolAtIndex:0], [copy symbolAtIndex:0]);
}

- (void)testMutableCopying {
    MPExpression *baseExpression = [[MPExpression alloc] initWithString:@"123"];
    MPMutableExpression *expression1 = [baseExpression mutableCopy];
    [expression1 appendFunction:[[MPFunction alloc] init]];
    MPExpression *expression2 = [[MPExpression alloc] initWithSymbols:@[@"123", [[MPFunction alloc] init]]];
    
    XCTAssertEqualObjects(expression1, expression2);
    XCTAssertNotEqualObjects(baseExpression, expression1);
}

// TODO: Test evaluating expressions

@end