guess.go

package gocuke

import (
	"fmt"
	"regexp"
	"strings"
	"unicode"

	messages "github.com/cucumber/messages/go/v21"
)

func guessMethodSig(step *messages.PickleStep) methodSig {
	parts := strings.Split(strings.TrimSpace(step.Text), " ")
	var (
		nameParts     []string
		paramTypes    []string
		regexParts    []string
		inSingleQuote bool
		inDoubleQuote bool
	)
	for i := 0; i < len(parts); i++ {
		part := parts[i]

		if inSingleQuote {
			if lastChar(part) == '\'' {
				inSingleQuote = false
			}
			continue
		}

		if inDoubleQuote {
			if lastChar(part) == '"' {
				inDoubleQuote = false
			}
			continue
		}

		c := firstChar(part)
		switch c {
		case '\'':
			if lastChar(part) != '\'' {
				inSingleQuote = true
			}
			paramTypes = append(paramTypes, "string")
			regexParts = append(regexParts, `'([^']*)'`)
			continue
		case '"':
			if lastChar(part) != '"' {
				inDoubleQuote = true
			}
			paramTypes = append(paramTypes, "string")
			regexParts = append(regexParts, `"([^"]*)"`)
			continue
		default:
			if decRegex.MatchString(part) {
				paramTypes = append(paramTypes, "*apd.Decimal")
				regexParts = append(regexParts, `(-?\d+\.\d+)`)
				continue
			}

			if intRegex.MatchString(part) {
				paramTypes = append(paramTypes, "int64")
				regexParts = append(regexParts, `(-?\d+)`)
				continue
			}
		}

		nameParts = append(nameParts, part)
		regexParts = append(regexParts, regexp.QuoteMeta(part))
	}

	regex := regexp.MustCompile(`^` + strings.Join(regexParts, `\s+`) + `$`)

	if step.Argument != nil {
		if step.Argument.DataTable != nil {
			paramTypes = append(paramTypes, "gocuke.DataTable")
		} else if step.Argument.DocString != nil {
			paramTypes = append(paramTypes, "gocuke.DocString")
		}
	}

	if len(nameParts) == 0 {
		return methodSig{name: "unknown", paramTypes: paramTypes, regex: regex}
	}

	var name string
	for i := 0; i < len(nameParts); i++ {
		n := toFirstUpperIdentifier(nameParts[i])
		if n == "" {
			continue
		}
		name = name + n
	}

	return methodSig{name: name, paramTypes: paramTypes, regex: regex}
}

func firstChar(x string) byte {
	return x[0]
}

func lastChar(x string) byte {
	return x[len(x)-1]
}

func toFirstUpperIdentifier(str string) string {
	var res []rune
	isFirst := true
	for _, r := range str {
		if isFirst {
			if !(unicode.IsLetter(r) || unicode.IsNumber(r)) {
				continue
			}

			res = append(res, unicode.ToUpper(r))
			isFirst = false
		} else {
			if !(unicode.IsLetter(r) || unicode.IsNumber(r)) {
				continue
			}

			res = append(res, unicode.ToLower(r))
		}
	}
	return string(res)
}

type methodSig struct {
	name       string
	paramTypes []string
	regex      *regexp.Regexp
}

func (m methodSig) methodSig() string {
	paramNames := make([]string, len(m.paramTypes))
	for i, paramType := range m.paramTypes {
		paramNames[i] = fmt.Sprintf("%s %s", string(rune('a'+i)), paramType)
	}

	return fmt.Sprintf(`%s(%s)`, m.name, strings.Join(paramNames, ", "))
}

func (m methodSig) methodSuggestion(suiteTypeName string) string {
	return fmt.Sprintf(`func (s %s) %s {
    panic("PENDING")
}`,
		suiteTypeName, m.methodSig())
}

func (m methodSig) stepSuggestion(suiteTypeName string) string {
	return fmt.Sprintf("Step(`%s`, (%s).%s)", m.regex.String(), suiteTypeName, m.name)
}

var decRegex = regexp.MustCompile(`^-?\d+\.\d+$`)
var intRegex = regexp.MustCompile(`^-?\d+$`)