package springdocs

import (
	"strings"
	"time"

	"github.com/PuerkitoBio/goquery"
	"github.com/yourorg/devour/pkg/parserutil"
)

type Parser struct {
	baseURL string
}

func NewParser() *Parser {
	return &Parser{
		baseURL: "https://docs.spring.io",
	}
}

func (p *Parser) ParseModulePage(html string, docURL string) (*Module, error) {
	doc, err := goquery.NewDocumentFromReader(strings.NewReader(html))
	if err != nil {
		return nil, err
	}

	module := &Module{
		DocURL:    docURL,
		FetchedAt: time.Now(),
	}

	module.Name = p.extractModuleName(doc)
	module.Doc = p.extractModuleDoc(doc)
	module.Version = p.extractVersion(doc)
	module.Classes = p.extractClasses(doc, module.Name, docURL)
	module.Properties = p.extractProperties(doc, docURL)
	module.Guides = p.extractGuides(doc, docURL)

	return module, nil
}

func (p *Parser) ParseSearchResults(html string) ([]*SearchResult, error) {
	doc, err := goquery.NewDocumentFromReader(strings.NewReader(html))
	if err != nil {
		return nil, err
	}

	var results []*SearchResult

	doc.Find(".search-result, .ais-Hits-item, article").Each(func(i int, s *goquery.Selection) {
		result := &SearchResult{}

		link := s.Find("a").First()
		result.Name = strings.TrimSpace(link.Text())

		if href, exists := link.Attr("href"); exists {
			result.DocURL = resolveURL(p.baseURL, href)
		}

		result.Doc = strings.TrimSpace(s.Find(".summary, .description, p").First().Text())

		if strings.Contains(result.DocURL, "/api/") {
			result.Kind = "class"
		} else if strings.Contains(result.DocURL, "/guides/") || strings.Contains(result.DocURL, "/tutorial/") {
			result.Kind = "guide"
		} else {
			result.Kind = "doc"
		}

		results = append(results, result)
	})

	return results, nil
}

func (p *Parser) extractModuleName(doc *goquery.Document) string {
	title := doc.Find("h1, .title, .page-title").First().Text()
	title = strings.TrimSpace(title)

	if title != "" {
		if idx := strings.Index(title, " "); idx > 0 {
			return title[:idx]
		}
		return title
	}

	return ""
}

func (p *Parser) extractModuleDoc(doc *goquery.Document) string {
	docblock := doc.Find(".paragraph:first-child p, .lead, #content p:first-of-type").First()
	return strings.TrimSpace(docblock.Text())
}

func (p *Parser) extractVersion(doc *goquery.Document) string {
	versionEl := doc.Find(".version, .doc-version, [data-version]")
	return strings.TrimSpace(versionEl.Text())
}

func (p *Parser) extractClasses(doc *goquery.Document, moduleName string, docURL string) []*Class {
	var classes []*Class

	doc.Find("table.table tbody tr, .api-list a, .class-link").Each(func(_ int, s *goquery.Selection) {
		class := &Class{}

		link := s.Find("a")
		if link.Length() == 0 {
			link = s
		}

		class.Name = strings.TrimSpace(link.Text())

		if href, exists := link.Attr("href"); exists {
			class.DocURL = resolveURL(docURL, href)
			if strings.Contains(href, "/api/") {
				class.QualifiedName = extractQualifiedName(href)
			}
		}

		class.Doc = strings.TrimSpace(s.Find(".description, td:last-child").Text())

		if class.Name != "" {
			classes = append(classes, class)
		}
	})

	return classes
}

func (p *Parser) extractProperties(doc *goquery.Document, docURL string) []*Property {
	var properties []*Property

	doc.Find(".configuration-property, table.properties tbody tr, .config-props dt").Each(func(_ int, s *goquery.Selection) {
		prop := &Property{}

		nameEl := s.Find(".property-name, code, strong, td:first-child").First()
		prop.Name = strings.TrimSpace(nameEl.Text())

		prop.Type = strings.TrimSpace(s.Find(".property-type, .type").Text())
		prop.Default = strings.TrimSpace(s.Find(".default-value, .default").Text())
		prop.Doc = strings.TrimSpace(s.Find(".description, dd, td:last-child").Text())

		if prop.Name != "" {
			properties = append(properties, prop)
		}
	})

	return properties
}

func (p *Parser) extractGuides(doc *goquery.Document, docURL string) []*Guide {
	var guides []*Guide

	doc.Find(".guide-link, .tutorial-link, .guide-card").Each(func(_ int, s *goquery.Selection) {
		guide := &Guide{}

		link := s.Find("a")
		if link.Length() == 0 {
			link = s
		}

		guide.Title = strings.TrimSpace(link.Text())

		if href, exists := link.Attr("href"); exists {
			guide.DocURL = resolveURL(docURL, href)
		}

		guide.Description = strings.TrimSpace(s.Find(".summary, .description").Text())

		if guide.Title != "" {
			guides = append(guides, guide)
		}
	})

	return guides
}

func (p *Parser) ParseClassPage(html string, docURL string) (*Class, error) {
	doc, err := goquery.NewDocumentFromReader(strings.NewReader(html))
	if err != nil {
		return nil, err
	}

	class := &Class{
		DocURL: docURL,
	}

	header := doc.Find("h1, .title, .class-name").First()
	class.Name = strings.TrimSpace(header.Text())
	class.QualifiedName = class.Name

	class.Doc = strings.TrimSpace(doc.Find(".class-description, .javadoc, .class-comment").First().Text())

	class.Methods = p.extractClassMethods(doc, class.Name, docURL)
	class.Fields = p.extractClassFields(doc, class.Name, docURL)
	class.Constructors = p.extractClassConstructors(doc, class.Name, docURL)

	return class, nil
}

func (p *Parser) extractClassMethods(doc *goquery.Document, className string, docURL string) []*Method {
	var methods []*Method

	doc.Find("table.method-summary tbody tr, .method, .member").Each(func(_ int, s *goquery.Selection) {
		method := &Method{
			IsConstructor: false,
		}

		link := s.Find("a").First()
		method.Name = strings.TrimSpace(link.Text())

		if method.Name == "" {
			sig := s.Find(".method-signature, code").Text()
			method.Name = extractSpringMethodName(sig)
		}

		method.Signature = strings.TrimSpace(s.Find(".method-signature, code").Text())
		method.Doc = strings.TrimSpace(s.Find(".method-description, td:last-child, dd").Text())

		if href, exists := link.Attr("href"); exists {
			if strings.HasPrefix(href, "#") {
				method.DocURL = docURL + href
			} else {
				method.DocURL = resolveURL(docURL, href)
			}
			method.QualifiedName = className + "." + method.Name
		}

		if method.Name != "" {
			methods = append(methods, method)
		}
	})

	return methods
}

func (p *Parser) extractClassFields(doc *goquery.Document, className string, docURL string) []*Field {
	var fields []*Field

	doc.Find("table.field-summary tbody tr, .field").Each(func(_ int, s *goquery.Selection) {
		field := &Field{}

		field.Name = strings.TrimSpace(s.Find(".field-name, a, td:first-child").Text())
		field.Type = strings.TrimSpace(s.Find(".field-type, td:nth-child(2)").Text())
		field.Doc = strings.TrimSpace(s.Find(".field-description, td:last-child").Text())

		if field.Name != "" {
			fields = append(fields, field)
		}
	})

	return fields
}

func (p *Parser) extractClassConstructors(doc *goquery.Document, className string, docURL string) []*Method {
	var constructors []*Method

	doc.Find("table.constructor-summary tbody tr, .constructor").Each(func(_ int, s *goquery.Selection) {
		ctor := &Method{
			IsConstructor: true,
			Name:          className,
		}

		ctor.Signature = strings.TrimSpace(s.Find(".constructor-signature, code").Text())
		ctor.Doc = strings.TrimSpace(s.Find(".constructor-description, td:last-child").Text())

		constructors = append(constructors, ctor)
	})

	return constructors
}

func extractSpringMethodName(sig string) string {
	sig = strings.TrimSpace(sig)
	if idx := strings.Index(sig, "("); idx > 0 {
		prefix := sig[:idx]
		parts := strings.Fields(prefix)
		if len(parts) > 0 {
			return parts[len(parts)-1]
		}
	}
	return ""
}

func extractQualifiedName(href string) string {
	href = strings.TrimSuffix(href, "/")
	parts := strings.Split(href, "/")
	if len(parts) >= 2 {
		return parts[len(parts)-1]
	}
	return ""
}

func resolveURL(base string, href string) string {
	return parserutil.ResolveURL(base, href)
}