package javadocs

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.oracle.com",
	}
}

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

	pkg := &Package{
		DocURL:    docURL,
		FetchedAt: time.Now(),
	}

	pkg.Name = p.extractPackageName(doc)
	pkg.Doc = p.extractPackageDoc(doc)
	pkg.Classes = p.extractClasses(doc, pkg.Name, docURL)
	pkg.Interfaces = p.extractInterfaces(doc, pkg.Name, docURL)
	pkg.Enums = p.extractEnums(doc, pkg.Name, docURL)
	pkg.Exceptions = p.extractExceptions(doc, pkg.Name, docURL)

	return pkg, 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(".result").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.Kind = s.Find(".result-kind").Text()
		result.QualName = s.Find(".qualified-name").Text()
		result.Package = s.Find(".package").Text()
		result.Doc = strings.TrimSpace(s.Find(".description").Text())

		results = append(results, result)
	})

	return results, nil
}

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

	if strings.Contains(title, "Package") {
		parts := strings.Fields(title)
		for i, part := range parts {
			if part == "Package" && i+1 < len(parts) {
				return parts[i+1]
			}
		}
	}

	if title != "" {
		return title
	}

	return ""
}

func (p *Parser) extractPackageDoc(doc *goquery.Document) string {
	docblock := doc.Find(".block, .description, #package-description").First()
	return strings.TrimSpace(docblock.Text())
}

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

	doc.Find("table.type-summary tr, .class-summary .member, section.class tbody tr").Each(func(_ int, s *goquery.Selection) {
		class := &Class{
			Package: pkgName,
			Kind:    ClassKindClass,
		}

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

		if class.Name == "" {
			class.Name = strings.TrimSpace(s.Find(".member-name, td:first-child").Text())
		}

		if href, exists := link.Attr("href"); exists {
			class.DocURL = resolveURL(docURL, href)
			class.QualifiedName = pkgName + "." + class.Name
		}

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

		if class.Name != "" && !strings.Contains(class.Name, "interface") {
			classes = append(classes, class)
		}
	})

	return classes
}

func (p *Parser) extractInterfaces(doc *goquery.Document, pkgName string, docURL string) []*Class {
	var interfaces []*Class

	doc.Find("table.interface-summary tr, .interface-summary .member").Each(func(_ int, s *goquery.Selection) {
		iface := &Class{
			Package: pkgName,
			Kind:    ClassKindInterface,
		}

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

		if iface.Name == "" {
			iface.Name = strings.TrimSpace(s.Find(".member-name").Text())
		}

		if href, exists := link.Attr("href"); exists {
			iface.DocURL = resolveURL(docURL, href)
			iface.QualifiedName = pkgName + "." + iface.Name
		}

		iface.Doc = strings.TrimSpace(s.Find(".member-summary, td:last-child").Text())

		if iface.Name != "" {
			interfaces = append(interfaces, iface)
		}
	})

	return interfaces
}

func (p *Parser) extractEnums(doc *goquery.Document, pkgName string, docURL string) []*Enum {
	var enums []*Enum

	doc.Find("table.enum-summary tr, .enum-summary .member").Each(func(_ int, s *goquery.Selection) {
		enum := &Enum{
			Package: pkgName,
		}

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

		if enum.Name == "" {
			enum.Name = strings.TrimSpace(s.Find(".member-name").Text())
		}

		if href, exists := link.Attr("href"); exists {
			enum.DocURL = resolveURL(docURL, href)
			enum.QualifiedName = pkgName + "." + enum.Name
		}

		enum.Doc = strings.TrimSpace(s.Find(".member-summary, td:last-child").Text())

		if enum.Name != "" {
			enums = append(enums, enum)
		}
	})

	return enums
}

func (p *Parser) extractExceptions(doc *goquery.Document, pkgName string, docURL string) []*Class {
	var exceptions []*Class

	doc.Find("table.exception-summary tr, .exception-summary .member").Each(func(_ int, s *goquery.Selection) {
		exc := &Class{
			Package: pkgName,
			Kind:    ClassKindClass,
		}

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

		if exc.Name == "" {
			exc.Name = strings.TrimSpace(s.Find(".member-name").Text())
		}

		if href, exists := link.Attr("href"); exists {
			exc.DocURL = resolveURL(docURL, href)
			exc.QualifiedName = pkgName + "." + exc.Name
		}

		exc.Doc = strings.TrimSpace(s.Find(".member-summary, td:last-child").Text())

		if exc.Name != "" {
			exceptions = append(exceptions, exc)
		}
	})

	return exceptions
}

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(".header, h1, .class-name").First()
	class.Name = strings.TrimSpace(header.Text())

	class.QualifiedName = class.Name
	if idx := strings.LastIndex(class.Name, "."); idx > 0 {
		class.Package = class.Name[:idx]
		class.Name = class.Name[idx+1:]
	}

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

	class.Methods = p.extractMethods(doc, class.Name, docURL)
	class.Fields = p.extractFields(doc, class.Name, docURL)
	class.Constructors = p.extractConstructors(doc, class.Name, docURL)

	return class, nil
}

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

	doc.Find("table.method-summary tr, .method-summary .member, section.method-detail > ul > li").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(".member-signature, code").Text()
			method.Name = extractMethodName(sig)
		}

		sigEl := s.Find(".member-signature, code, .sig")
		method.Signature = strings.TrimSpace(sigEl.Text())

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

		method.Doc = strings.TrimSpace(s.Find(".block, .member-summary, dd").First().Text())

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

	return methods
}

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

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

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

		if field.Name == "" {
			field.Name = strings.TrimSpace(s.Find(".member-name, td:first-child").Text())
		}

		field.Type = strings.TrimSpace(s.Find(".member-type, td:nth-child(2)").Text())
		field.Doc = strings.TrimSpace(s.Find(".member-summary, td:last-child").Text())

		if id, exists := s.Attr("id"); exists {
			field.DocURL = docURL + "#" + id
		}

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

	return fields
}

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

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

		link := s.Find("a").First()
		if name := strings.TrimSpace(link.Text()); name != "" {
			ctor.Name = name
		}

		sigEl := s.Find(".member-signature, code")
		ctor.Signature = strings.TrimSpace(sigEl.Text())

		ctor.Doc = strings.TrimSpace(s.Find(".block, .member-summary, td:last-child").Text())

		if id, exists := s.Attr("id"); exists {
			ctor.DocURL = docURL + "#" + id
		}

		constructors = append(constructors, ctor)
	})

	return constructors
}

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