package expressions

import (
	"errors"
	"regexp"
	"strings"
)

var unresolvedVariablesRegex = regexp.MustCompile(`(?:%7[B|b]|{){2}([^}]+)(?:%7[D|d]|}){2}["')}]*`)

// ContainsUnresolvedVariables returns an error with variable names if the passed
// input contains unresolved {{<pattern-here>}} variables.
func ContainsUnresolvedVariables(items ...string) error {
	for _, data := range items {
		matches := unresolvedVariablesRegex.FindAllStringSubmatch(data, -1)
		if len(matches) == 0 {
			return nil
		}
		errorString := &strings.Builder{}
		errorString.WriteString("unresolved variables found: ")

		for i, match := range matches {
			if len(match) < 2 {
				continue
			}
			errorString.WriteString(match[1])
			if i != len(matches)-1 {
				errorString.WriteString(",")
			}
		}
		errorMessage := errorString.String()
		return errors.New(errorMessage)
	}

	return nil
}

func ContainsVariablesWithNames(names map[string]interface{}, items ...string) error {
	for _, data := range items {
		matches := unresolvedVariablesRegex.FindAllStringSubmatch(data, -1)
		if len(matches) == 0 {
			return nil
		}
		errorString := &strings.Builder{}
		errorString.WriteString("unresolved variables with values found: ")

		for i, match := range matches {
			if len(match) < 2 {
				continue
			}
			matchName := match[1]
			if _, ok := names[matchName]; !ok {
				errorString.WriteString(matchName)
				if i != len(matches)-1 {
					errorString.WriteString(",")
				}
			}
		}
		errorMessage := errorString.String()
		return errors.New(errorMessage)
	}

	return nil
}