package models

import (
	"bufio"
	"fmt"
	"strings"
	"time"
	"unicode"
)

type Post struct {
	ID          int64
	SiteID      int64
	GUID        string
	Title       string
	Body        string
	Slug        string
	CreatedAt   time.Time
	PublishedAt time.Time
}

func (p *Post) BestSlug() string {
	if p.Slug != "" {
		return p.Slug
	}

	bestDateToUse := p.PublishedAt
	if bestDateToUse.IsZero() {
		bestDateToUse = p.CreatedAt
	}

	slugPath := firstNWords(p.Title, 3, wordForSlug)
	if slugPath == "" {
		slugPath = firstNWords(p.Body, 3, wordForSlug)
	}
	if slugPath != "" {
		slugPath = strings.Replace(strings.ToLower(slugPath), " ", "-", -1)
	} else {
		slugPath = p.GUID
		if slugPath == "" {
			slugPath = bestDateToUse.Format("150405")
		}
	}

	datePart := fmt.Sprintf("%04d/%02d/%02d", bestDateToUse.Year(), bestDateToUse.Month(), bestDateToUse.Day())
	return fmt.Sprintf("/%s/%s", datePart, slugPath)
}

func wordForSlug(word string) string {
	var sb strings.Builder
	for _, c := range word {
		if unicode.IsLetter(c) || unicode.IsNumber(c) {
			sb.WriteRune(c)
		}
	}
	return sb.String()
}

func firstNWords(s string, n int, keepWord func(word string) string) string {
	if n == 0 {
		return ""
	}

	suitableWords := make([]string, 0, n)

	scnr := bufio.NewScanner(strings.NewReader(s))
	scnr.Split(bufio.ScanWords)
	for scnr.Scan() {
		word := scnr.Text()
		if w := keepWord(word); w != "" {
			suitableWords = append(suitableWords, w)
			if len(suitableWords) >= n {
				break
			}
		}
	}
	return strings.Join(suitableWords, " ")
}