1package q
2
3import (
4	"bufio"
5	"fmt"
6	"os"
7	"regexp"
8	"runtime"
9	"strings"
10)
11
12// Choose how to write the function name in the file.
13//
14// e.g. test functions can be long and have multiple parts, so we just
15// pull out the most meaningful part.
16func chooseDisplayName(functionName string) string {
17	parts := strings.Split(functionName, ".")
18
19	// If this is an anonymous function, the name will be something like
20	// "func1", which is unhelpful.
21	//
22	// Throw away that part and get the next part.
23	if m, _ := regexp.MatchString("^func[0-9]+$", parts[len(parts)-1]); len(parts) > 1 && m {
24		fmt.Println(m)
25		return parts[len(parts)-2]
26	}
27
28	return parts[len(parts)-1]
29}
30
31func getFunctionName() string {
32	pc, _, _, ok := runtime.Caller(2)
33	if !ok {
34		return "<unknown>"
35	}
36
37	fn := runtime.FuncForPC(pc)
38	if fn == nil {
39		return "<unknown>"
40	}
41
42	return chooseDisplayName(fn.Name())
43}
44
45func getExpression() string {
46	_, file, line, ok := runtime.Caller(2)
47	if !ok {
48		return "<unknown>"
49	}
50
51	f, err := os.Open(file)
52	if err != nil {
53		return "<unknown>"
54	}
55	defer f.Close()
56
57	scanner := bufio.NewScanner(f)
58	currentLine := 1
59
60	for scanner.Scan() {
61		if currentLine == line {
62			thisLine := strings.TrimSpace(scanner.Text())
63			thisLine, _ = strings.CutPrefix(thisLine, "q.Q(")
64			thisLine, _ = strings.CutSuffix(thisLine, ")")
65			return thisLine
66		}
67		currentLine++
68	}
69
70	if err := scanner.Err(); err != nil {
71		return "<unknown>"
72	}
73
74	return "<unknown>"
75}
76
77func toString(value any, a ...any) string {
78	switch v := value.(type) {
79	case string:
80		if len(a) == 0 {
81			return fmt.Sprintf("%q", v)
82		} else {
83			v = strings.ReplaceAll(v, "%+v", "\x1b[39m%+v\x1b[39m")
84			v = strings.ReplaceAll(v, "%v", "\x1b[39m%v\x1b[39m")
85			v = strings.ReplaceAll(v, "%t", "\x1b[39m%t\x1b[39m")
86			return fmt.Sprintf(v, a...)
87		}
88	case int, int8, int16, int32, int64,
89		uint, uint8, uint16, uint32, uint64,
90		float32, float64, bool:
91		return fmt.Sprintf("%v", v)
92	case fmt.Stringer:
93		return v.String()
94	default:
95		return fmt.Sprintf("%+v", v) // fallback
96	}
97}
98
99func Q(value any, a ...any) {
100	f, err := os.OpenFile("/tmp/q.txt", os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
101	if err != nil {
102		panic(err)
103	}
104	defer f.Close()
105
106	functionName := getFunctionName()
107	expression := getExpression()
108
109	var line string
110
111	if expression[0] == '"' && expression[len(expression)-1] == '"' {
112		line = "\x1b[32m" + functionName + "\x1b[39m: " + toString(value, a...) + "\n\n"
113	} else {
114		line = "\x1b[32m" + functionName + "\x1b[39m: " + expression + " = \x1b[36m" + toString(value, a...) + "\x1b[39m\n\n"
115	}
116
117	if _, err = f.WriteString(line); err != nil {
118		panic(err)
119	}
120}