package scraper

import (
	"bytes"
	"errors"
	"net/url"
	"regexp"
	"strings"

	"github.com/antchfx/htmlquery"

	"golang.org/x/net/html"

	"github.com/stashapp/stash/pkg/logger"
	"github.com/stashapp/stash/pkg/models"
)

type xpathScraper struct {
	scraper      scraperTypeConfig
	config       config
	globalConfig GlobalConfig
	txnManager   models.TransactionManager
}

func newXpathScraper(scraper scraperTypeConfig, txnManager models.TransactionManager, config config, globalConfig GlobalConfig) *xpathScraper {
	return &xpathScraper{
		scraper:      scraper,
		config:       config,
		globalConfig: globalConfig,
		txnManager:   txnManager,
	}
}

func (s *xpathScraper) getXpathScraper() *mappedScraper {
	return s.config.XPathScrapers[s.scraper.Scraper]
}

func (s *xpathScraper) scrapeURL(url string) (*html.Node, *mappedScraper, error) {
	scraper := s.getXpathScraper()

	if scraper == nil {
		return nil, nil, errors.New("xpath scraper with name " + s.scraper.Scraper + " not found in config")
	}

	doc, err := s.loadURL(url)

	if err != nil {
		return nil, nil, err
	}

	return doc, scraper, nil
}

func (s *xpathScraper) scrapePerformerByURL(url string) (*models.ScrapedPerformer, error) {
	u := replaceURL(url, s.scraper) // allow a URL Replace for performer by URL queries
	doc, scraper, err := s.scrapeURL(u)
	if err != nil {
		return nil, err
	}

	q := s.getXPathQuery(doc)
	return scraper.scrapePerformer(q)
}

func (s *xpathScraper) scrapeSceneByURL(url string) (*models.ScrapedScene, error) {
	u := replaceURL(url, s.scraper) // allow a URL Replace for scene by URL queries
	doc, scraper, err := s.scrapeURL(u)
	if err != nil {
		return nil, err
	}

	q := s.getXPathQuery(doc)
	return scraper.scrapeScene(q)
}

func (s *xpathScraper) scrapeGalleryByURL(url string) (*models.ScrapedGallery, error) {
	u := replaceURL(url, s.scraper) // allow a URL Replace for gallery by URL queries
	doc, scraper, err := s.scrapeURL(u)
	if err != nil {
		return nil, err
	}

	q := s.getXPathQuery(doc)
	return scraper.scrapeGallery(q)
}

func (s *xpathScraper) scrapeMovieByURL(url string) (*models.ScrapedMovie, error) {
	u := replaceURL(url, s.scraper) // allow a URL Replace for movie by URL queries
	doc, scraper, err := s.scrapeURL(u)
	if err != nil {
		return nil, err
	}

	q := s.getXPathQuery(doc)
	return scraper.scrapeMovie(q)
}

func (s *xpathScraper) scrapePerformersByName(name string) ([]*models.ScrapedPerformer, error) {
	scraper := s.getXpathScraper()

	if scraper == nil {
		return nil, errors.New("xpath scraper with name " + s.scraper.Scraper + " not found in config")
	}

	const placeholder = "{}"

	// replace the placeholder string with the URL-escaped name
	escapedName := url.QueryEscape(name)

	url := s.scraper.QueryURL
	url = strings.Replace(url, placeholder, escapedName, -1)

	doc, err := s.loadURL(url)

	if err != nil {
		return nil, err
	}

	q := s.getXPathQuery(doc)
	return scraper.scrapePerformers(q)
}

func (s *xpathScraper) scrapePerformerByFragment(scrapedPerformer models.ScrapedPerformerInput) (*models.ScrapedPerformer, error) {
	return nil, errors.New("scrapePerformerByFragment not supported for xpath scraper")
}

func (s *xpathScraper) scrapeSceneByFragment(scene models.SceneUpdateInput) (*models.ScrapedScene, error) {
	storedScene, err := sceneFromUpdateFragment(scene, s.txnManager)
	if err != nil {
		return nil, err
	}

	if storedScene == nil {
		return nil, errors.New("no scene found")
	}

	// construct the URL
	queryURL := queryURLParametersFromScene(storedScene)
	if s.scraper.QueryURLReplacements != nil {
		queryURL.applyReplacements(s.scraper.QueryURLReplacements)
	}
	url := queryURL.constructURL(s.scraper.QueryURL)

	scraper := s.getXpathScraper()

	if scraper == nil {
		return nil, errors.New("xpath scraper with name " + s.scraper.Scraper + " not found in config")
	}

	doc, err := s.loadURL(url)

	if err != nil {
		return nil, err
	}

	q := s.getXPathQuery(doc)
	return scraper.scrapeScene(q)
}

func (s *xpathScraper) scrapeGalleryByFragment(gallery models.GalleryUpdateInput) (*models.ScrapedGallery, error) {
	storedGallery, err := galleryFromUpdateFragment(gallery, s.txnManager)
	if err != nil {
		return nil, err
	}

	if storedGallery == nil {
		return nil, errors.New("no scene found")
	}

	// construct the URL
	queryURL := queryURLParametersFromGallery(storedGallery)
	if s.scraper.QueryURLReplacements != nil {
		queryURL.applyReplacements(s.scraper.QueryURLReplacements)
	}
	url := queryURL.constructURL(s.scraper.QueryURL)

	scraper := s.getXpathScraper()

	if scraper == nil {
		return nil, errors.New("xpath scraper with name " + s.scraper.Scraper + " not found in config")
	}

	doc, err := s.loadURL(url)

	if err != nil {
		return nil, err
	}

	q := s.getXPathQuery(doc)
	return scraper.scrapeGallery(q)
}

func (s *xpathScraper) loadURL(url string) (*html.Node, error) {
	r, err := loadURL(url, s.config, s.globalConfig)
	if err != nil {
		return nil, err
	}

	ret, err := html.Parse(r)

	if err == nil && s.config.DebugOptions != nil && s.config.DebugOptions.PrintHTML {
		var b bytes.Buffer
		html.Render(&b, ret)
		logger.Infof("loadURL (%s) response: \n%s", url, b.String())
	}

	return ret, err
}

func (s *xpathScraper) getXPathQuery(doc *html.Node) *xpathQuery {
	return &xpathQuery{
		doc:     doc,
		scraper: s,
	}
}

type xpathQuery struct {
	doc     *html.Node
	scraper *xpathScraper
}

func (q *xpathQuery) runQuery(selector string) []string {
	found, err := htmlquery.QueryAll(q.doc, selector)
	if err != nil {
		logger.Warnf("Error parsing xpath expression '%s': %s", selector, err.Error())
		return nil
	}

	var ret []string
	for _, n := range found {
		// don't add empty strings
		nodeText := q.nodeText(n)
		if nodeText != "" {
			ret = append(ret, q.nodeText(n))
		}
	}

	return ret
}

func (q *xpathQuery) nodeText(n *html.Node) string {
	var ret string
	if n != nil && n.Type == html.CommentNode {
		ret = htmlquery.OutputHTML(n, true)
	} else {
		ret = htmlquery.InnerText(n)
	}

	// trim all leading and trailing whitespace
	ret = strings.TrimSpace(ret)

	// remove multiple whitespace
	re := regexp.MustCompile("  +")
	ret = re.ReplaceAllString(ret, " ")

	// TODO - make this optional
	re = regexp.MustCompile("\n")
	ret = re.ReplaceAllString(ret, "")

	return ret
}

func (q *xpathQuery) subScrape(value string) mappedQuery {
	doc, err := q.scraper.loadURL(value)

	if err != nil {
		logger.Warnf("Error getting URL '%s' for sub-scraper: %s", value, err.Error())
		return nil
	}

	return q.scraper.getXPathQuery(doc)
}