package services

import (
	"fmt"
	"io"
	"net/url"
	"path"
	"strings"

	"arma3-web-server/internal/models"
	"golang.org/x/net/html"
)

func ParseModlistHTML(r io.Reader) (string, []models.ModEntry, error) {
	doc, err := html.Parse(r)
	if err != nil {
		return "", nil, fmt.Errorf("parse html: %w", err)
	}

	var mods []models.ModEntry
	seen := map[string]bool{}

	var walk func(*html.Node)
	walk = func(n *html.Node) {
		if n.Type == html.ElementNode && n.Data == "tr" {
			if name, id, ok := extractModRow(n); ok && id != "" {
				if !seen[id] {
					seen[id] = true
					mods = append(mods, models.ModEntry{
						ID:      id,
						Name:    cleanModName(name),
						Enabled: true,
					})
				}
			}
		}
		for c := n.FirstChild; c != nil; c = c.NextSibling {
			walk(c)
		}
	}
	walk(doc)

	if mods == nil {
		mods = []models.ModEntry{}
	}
	return "", mods, nil
}

func extractModRow(tr *html.Node) (name, id string, ok bool) {
	var cells []*html.Node
	for c := tr.FirstChild; c != nil; c = c.NextSibling {
		if c.Type == html.ElementNode && c.Data == "td" {
			cells = append(cells, c)
		}
	}
	if len(cells) < 3 {
		return "", "", false
	}

	name = extractText(cells[0])

	for c := cells[2].FirstChild; c != nil; c = c.NextSibling {
		if c.Type == html.ElementNode && c.Data == "a" {
			id = extractWorkshopID(c)
			break
		}
	}

	if name == "" {
		return "", "", false
	}
	return name, id, true
}

func extractText(n *html.Node) string {
	var b strings.Builder
	var walk func(*html.Node)
	walk = func(n *html.Node) {
		if n.Type == html.TextNode {
			b.WriteString(n.Data)
		}
		for c := n.FirstChild; c != nil; c = c.NextSibling {
			walk(c)
		}
	}
	walk(n)
	return strings.TrimSpace(b.String())
}

func extractWorkshopID(a *html.Node) string {
	for _, attr := range a.Attr {
		if attr.Key == "href" {
			u, err := url.Parse(attr.Val)
			if err != nil {
				continue
			}
			return u.Query().Get("id")
		}
	}
	return ""
}

func cleanModName(name string) string {
	name = strings.TrimSpace(name)
	name = strings.ReplaceAll(name, "/", "_")
	name = strings.ReplaceAll(name, "\\", "_")
	return name
}

func FileNameToModlistName(filename string) string {
	ext := path.Ext(filename)
	name := strings.TrimSuffix(filename, ext)
	name = strings.ReplaceAll(name, "_", " ")
	name = strings.ReplaceAll(name, "-", " ")
	return name
}