1package matchers
2
3import (
4	"fmt"
5	"math"
6
7	"github.com/onsi/gomega/format"
8)
9
10type BeNumericallyMatcher struct {
11	Comparator string
12	CompareTo  []interface{}
13}
14
15func (matcher *BeNumericallyMatcher) FailureMessage(actual interface{}) (message string) {
16	return matcher.FormatFailureMessage(actual, false)
17}
18
19func (matcher *BeNumericallyMatcher) NegatedFailureMessage(actual interface{}) (message string) {
20	return matcher.FormatFailureMessage(actual, true)
21}
22
23func (matcher *BeNumericallyMatcher) FormatFailureMessage(actual interface{}, negated bool) (message string) {
24	if len(matcher.CompareTo) == 1 {
25		message = fmt.Sprintf("to be %s", matcher.Comparator)
26	} else {
27		message = fmt.Sprintf("to be within %v of %s", matcher.CompareTo[1], matcher.Comparator)
28	}
29	if negated {
30		message = "not " + message
31	}
32	return format.Message(actual, message, matcher.CompareTo[0])
33}
34
35func (matcher *BeNumericallyMatcher) Match(actual interface{}) (success bool, err error) {
36	if len(matcher.CompareTo) == 0 || len(matcher.CompareTo) > 2 {
37		return false, fmt.Errorf("BeNumerically requires 1 or 2 CompareTo arguments.  Got:\n%s", format.Object(matcher.CompareTo, 1))
38	}
39	if !isNumber(actual) {
40		return false, fmt.Errorf("Expected a number.  Got:\n%s", format.Object(actual, 1))
41	}
42	if !isNumber(matcher.CompareTo[0]) {
43		return false, fmt.Errorf("Expected a number.  Got:\n%s", format.Object(matcher.CompareTo[0], 1))
44	}
45	if len(matcher.CompareTo) == 2 && !isNumber(matcher.CompareTo[1]) {
46		return false, fmt.Errorf("Expected a number.  Got:\n%s", format.Object(matcher.CompareTo[0], 1))
47	}
48
49	switch matcher.Comparator {
50	case "==", "~", ">", ">=", "<", "<=":
51	default:
52		return false, fmt.Errorf("Unknown comparator: %s", matcher.Comparator)
53	}
54
55	if isFloat(actual) || isFloat(matcher.CompareTo[0]) {
56		var secondOperand float64 = 1e-8
57		if len(matcher.CompareTo) == 2 {
58			secondOperand = toFloat(matcher.CompareTo[1])
59		}
60		success = matcher.matchFloats(toFloat(actual), toFloat(matcher.CompareTo[0]), secondOperand)
61	} else if isInteger(actual) {
62		var secondOperand int64 = 0
63		if len(matcher.CompareTo) == 2 {
64			secondOperand = toInteger(matcher.CompareTo[1])
65		}
66		success = matcher.matchIntegers(toInteger(actual), toInteger(matcher.CompareTo[0]), secondOperand)
67	} else if isUnsignedInteger(actual) {
68		var secondOperand uint64 = 0
69		if len(matcher.CompareTo) == 2 {
70			secondOperand = toUnsignedInteger(matcher.CompareTo[1])
71		}
72		success = matcher.matchUnsignedIntegers(toUnsignedInteger(actual), toUnsignedInteger(matcher.CompareTo[0]), secondOperand)
73	} else {
74		return false, fmt.Errorf("Failed to compare:\n%s\n%s:\n%s", format.Object(actual, 1), matcher.Comparator, format.Object(matcher.CompareTo[0], 1))
75	}
76
77	return success, nil
78}
79
80func (matcher *BeNumericallyMatcher) matchIntegers(actual, compareTo, threshold int64) (success bool) {
81	switch matcher.Comparator {
82	case "==", "~":
83		diff := actual - compareTo
84		return -threshold <= diff && diff <= threshold
85	case ">":
86		return (actual > compareTo)
87	case ">=":
88		return (actual >= compareTo)
89	case "<":
90		return (actual < compareTo)
91	case "<=":
92		return (actual <= compareTo)
93	}
94	return false
95}
96
97func (matcher *BeNumericallyMatcher) matchUnsignedIntegers(actual, compareTo, threshold uint64) (success bool) {
98	switch matcher.Comparator {
99	case "==", "~":
100		if actual < compareTo {
101			actual, compareTo = compareTo, actual
102		}
103		return actual-compareTo <= threshold
104	case ">":
105		return (actual > compareTo)
106	case ">=":
107		return (actual >= compareTo)
108	case "<":
109		return (actual < compareTo)
110	case "<=":
111		return (actual <= compareTo)
112	}
113	return false
114}
115
116func (matcher *BeNumericallyMatcher) matchFloats(actual, compareTo, threshold float64) (success bool) {
117	switch matcher.Comparator {
118	case "~":
119		return math.Abs(actual-compareTo) <= threshold
120	case "==":
121		return (actual == compareTo)
122	case ">":
123		return (actual > compareTo)
124	case ">=":
125		return (actual >= compareTo)
126	case "<":
127		return (actual < compareTo)
128	case "<=":
129		return (actual <= compareTo)
130	}
131	return false
132}
133