// Package parser provides message text parsing utilities for the CRM.
// It extracts structured lead information from raw WhatsApp message text.
package parser

import (
	"regexp"
	"strings"
	"unicode"

	"golang.org/x/text/unicode/norm"
)

// ExtractService scans msg for any keyword in the mapping (case-insensitive,
// accent-insensitive) and returns the corresponding service name.
// If no keyword matches, it returns "Não especificou".
//
// mapping is a map[keyword]serviceName loaded from the service_keywords table.
func ExtractService(msg string, mapping map[string]string) string {
	normalized := normalizeText(msg)

	// Sort by keyword length descending so longer phrases match before shorter ones.
	// We iterate the map which has no order, so we do two passes:
	// first collect all matches, then pick the longest keyword match.
	type match struct {
		keyword string
		service string
	}
	var best match

	for kw, svc := range mapping {
		normKW := normalizeText(kw)
		if strings.Contains(normalized, normKW) {
			if len(kw) > len(best.keyword) {
				best = match{keyword: kw, service: svc}
			}
		}
	}

	if best.service != "" {
		return best.service
	}
	return "Não especificou"
}

// NormalizePhone converts a raw WhatsApp phone string to E.164 format (+countrycode...).
// It strips the @s.whatsapp.net suffix, removes non-digit characters, and prepends "+".
func NormalizePhone(raw string) string {
	// Strip WhatsApp JID suffix.
	if idx := strings.Index(raw, "@"); idx != -1 {
		raw = raw[:idx]
	}
	// Keep only digits.
	digits := regexp.MustCompile(`\D`).ReplaceAllString(raw, "")
	if digits == "" {
		return raw
	}
	return "+" + digits
}

// normalizeText lowercases and removes accents from s for fuzzy comparison.
func normalizeText(s string) string {
	// NFD decomposition splits accented characters into base + combining marks.
	t := norm.NFD.String(strings.ToLower(s))
	// Remove combining marks (Unicode category Mn).
	var b strings.Builder
	for _, r := range t {
		if unicode.Is(unicode.Mn, r) {
			continue
		}
		b.WriteRune(r)
	}
	return b.String()
}