package fa

import (
	"strconv"
	"strings"
	"time"

	"github.com/PuerkitoBio/goquery"
)

// parsePopupDate reads a FurAffinity popup_date element. Every popup_date on
// the site carries an authoritative `data-time` attribute holding the post
// time as Unix seconds; that is preferred. The visible title attribute is a
// fallback for older rendered pages that omit data-time.
//
// Returns the zero time if neither source is parseable. Callers check IsZero
// rather than receiving an error, because dates are nice-to-have and
// shouldn't fail a whole parse on their own.
func parsePopupDate(s *goquery.Selection) time.Time {
	if s == nil || s.Length() == 0 {
		return time.Time{}
	}
	if v := trimAttr(s, "data-time"); v != "" {
		if secs, err := strconv.ParseInt(v, 10, 64); err == nil && secs > 0 {
			return time.Unix(secs, 0).UTC()
		}
	}
	raw := firstNonEmpty(trimAttr(s, "title"), trimText(s))
	if t, err := ParseFADate(raw); err == nil {
		return t
	}
	return time.Time{}
}

// extractIntFromHref pulls the first /<numeric>/ segment from an href.
// Returns 0 if none is found. Used to lift submission/journal/comment IDs
// out of links like "/view/12345678/" or "/journal/4567890/".
func extractIntFromHref(href string) int64 {
	for _, seg := range strings.Split(href, "/") {
		if seg == "" {
			continue
		}
		if n, err := strconv.ParseInt(seg, 10, 64); err == nil {
			return n
		}
	}
	return 0
}

// trimText is the goquery-friendly equivalent of strings.TrimSpace applied
// to a selection's text. Returns "" when the selection is empty.
func trimText(s *goquery.Selection) string {
	if s == nil || s.Length() == 0 {
		return ""
	}
	return strings.TrimSpace(s.Text())
}

// trimAttr returns the trimmed value of attr, or "" if missing.
func trimAttr(s *goquery.Selection, attr string) string {
	if s == nil || s.Length() == 0 {
		return ""
	}
	v, ok := s.Attr(attr)
	if !ok {
		return ""
	}
	return strings.TrimSpace(v)
}

// firstNonEmpty returns the first non-empty (after trim) string.
func firstNonEmpty(vals ...string) string {
	for _, v := range vals {
		if t := strings.TrimSpace(v); t != "" {
			return t
		}
	}
	return ""
}

// htmlOf returns the inner HTML of a selection, with leading/trailing
// whitespace trimmed. Returns "" when the selection is empty or rendering fails.
func htmlOf(s *goquery.Selection) string {
	if s == nil || s.Length() == 0 {
		return ""
	}
	h, err := s.Html()
	if err != nil {
		return ""
	}
	return strings.TrimSpace(h)
}

// parseStatNumber parses a number that may carry commas or surrounding text
// (e.g. "1,234 views"). Returns 0 on any failure rather than propagating an
// error stats are nice-to-have, not load-bearing.
func parseStatNumber(s string) int {
	s = strings.TrimSpace(s)
	if s == "" {
		return 0
	}
	// Strip everything that isn't a digit or comma; keep digits & commas only.
	var b strings.Builder
	for _, r := range s {
		if r >= '0' && r <= '9' {
			b.WriteRune(r)
		}
	}
	if b.Len() == 0 {
		return 0
	}
	n, err := strconv.Atoi(b.String())
	if err != nil {
		return 0
	}
	return n
}