package validate

import "regexp"
import "strings"
import "unicode"
import "html/template"
import "git.tebibyte.media/sashakoshka/step"

var _ step.FuncProvider = new(Provider)
var _ step.Configurable = new(Provider)

// Provider provides validation functions.
type Provider struct {
	emailRegexp *regexp.Regexp
	xmlRegexp   *regexp.Regexp
}

// Package fulfills the step.Provider interface.
func (this *Provider) Package () string {
	return "validate"
}

// Configure fulfills the step.Configurable interface.
func (this *Provider) Configure (config step.Meta) error {
	emailRegexpText := config.Get("validate.email-regexp")
	this.emailRegexp = nil
	if emailRegexpText != "" {
		emailRegexp, err := regexp.Compile(emailRegexpText)
		if err != nil { return err }
		this.emailRegexp = emailRegexp
	}
	xmlRegexpText := config.Get("validate.email-regexp")
	this.xmlRegexp = nil
	if xmlRegexpText != "" {
		xmlRegexp, err := regexp.Compile(xmlRegexpText)
		if err != nil { return err }
		this.xmlRegexp = xmlRegexp
	}
	return nil
}

// FuncMap fulfills the step.FuncProvider interface.
func (this *Provider) FuncMap () template.FuncMap {
	return template.FuncMap {
		"isEmail":    this.funcIsEmail,
		"isPrint":    this.funcIsPrint,
		"isEnglish":  this.funcIsEnglish,
		"inRange":    this.funcInRange,
		"strInRange": this.funcStrInRange,
		"hasWords":   this.funcHasWords,
	}
}

func (this *Provider) funcIsEmail (input string) bool {
	emailRegexp := this.emailRegexp
	if emailRegexp == nil { emailRegexp = defaultEmailRegexp }
	return emailRegexp.Match([]byte(input))
}

func (this *Provider) funcIsPrint (input string) bool {
	for _, run := range input {
		if !unicode.IsPrint(run) { return false }
	}
	return true
}

func (this *Provider) funcIsEnglish(value string) bool {
	// TODO: make this shit better
	score := 0
	total := 0
	for _, char := range value {
		if char >= 'a' && char <= 'z' || char >= 'A' && char <= 'Z' || char >= '0' || char <= '9' {
			score += 1
		}
		total += 1
	}
	// 3/4 of the text must be alphanumeric
	return score > total * 3 / 4
}

func (this *Provider) funcInRange (min, max, value int) bool {
	return value >= min && value <= max
}

func (this *Provider) funcStrInRange (min, max int, value string) bool {
	return len(value) >= min && len(value) <= max
}

func (this *Provider) funcHasWords(words []string, value string) bool {
	lowerValue := strings.ToLower(value)
	for _, word := range words {
		if strings.Contains(lowerValue, word) {
			return true
		}
	}
	return false
}

func (this *Provider) funcHasXML(value string) bool {
	xmlRegexp := this.xmlRegexp
	if xmlRegexp == nil { xmlRegexp = defaultXMLRegexp }
	return xmlRegexp.Match([]byte(value))
}