package scraper

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"net/http"
	"strings"
	"time"

	"github.com/yourorg/devour/pkg/javadocs"
)

type JavaDocsScraper struct {
	config *Config
	parser *javadocs.Parser
	client *http.Client
}

func NewJavaDocsScraper(config *Config) *JavaDocsScraper {
	return &JavaDocsScraper{
		config: config,
		parser: javadocs.NewParser(),
		client: &http.Client{
			Timeout: config.Timeout,
		},
	}
}

func (s *JavaDocsScraper) Scrape(ctx context.Context, source *Source) ([]*Document, error) {
	var documents []*Document

	if source.URL == "" {
		return nil, fmt.Errorf("URL is required for Java docs scraper")
	}

	html, err := s.fetchPage(ctx, source.URL)
	if err != nil {
		return nil, fmt.Errorf("failed to fetch page: %w", err)
	}

	pkg, err := s.parser.ParsePackagePage(html, source.URL)
	if err != nil {
		return nil, fmt.Errorf("failed to parse package: %w", err)
	}

	mainDoc := s.packageToDocument(pkg, source.Name)
	documents = append(documents, mainDoc)

	for _, class := range pkg.Classes {
		doc := s.classToDocument(class, pkg, source.Name)
		documents = append(documents, doc)
	}

	for _, iface := range pkg.Interfaces {
		doc := s.interfaceToDocument(iface, pkg, source.Name)
		documents = append(documents, doc)
	}

	for _, enum := range pkg.Enums {
		doc := s.enumToDocument(enum, pkg, source.Name)
		documents = append(documents, doc)
	}

	for _, exc := range pkg.Exceptions {
		doc := s.exceptionToDocument(exc, pkg, source.Name)
		documents = append(documents, doc)
	}

	return documents, nil
}

func (s *JavaDocsScraper) DetectChanges(ctx context.Context, source *Source, lastHash string) (bool, string, error) {
	html, err := s.fetchPage(ctx, source.URL)
	if err != nil {
		return false, "", err
	}

	hash := s.generateHash(html)
	changed := hash != lastHash

	return changed, hash, nil
}

func (s *JavaDocsScraper) fetchPage(ctx context.Context, url string) (string, error) {
	return fetchExternalPage(ctx, s.client, s.config.UserAgent, url)
}

func (s *JavaDocsScraper) generateHash(content string) string {
	hash := sha256.Sum256([]byte(content))
	return hex.EncodeToString(hash[:])
}

func (s *JavaDocsScraper) packageToDocument(pkg *javadocs.Package, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# Package %s\n\n", pkg.Name)
	fmt.Fprintf(&content, "%s\n", pkg.Doc)

	metadata := map[string]interface{}{
		"package":  pkg.Name,
		"doc_url":  pkg.DocURL,
		"doc_type": "java-package",
	}

	return &Document{
		ID:        generateDocID(pkg.DocURL),
		Source:    sourceName,
		Type:      "java-package",
		Title:     pkg.Name,
		Content:   content.String(),
		URL:       pkg.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}

func (s *JavaDocsScraper) classToDocument(class *javadocs.Class, pkg *javadocs.Package, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s\n\n", class.QualifiedName)
	fmt.Fprintf(&content, "Kind: %s\n\n", class.Kind)
	fmt.Fprintf(&content, "%s\n", class.Doc)

	if len(class.Methods) > 0 {
		fmt.Fprintf(&content, "\n## Methods\n")
		for _, m := range class.Methods {
			fmt.Fprintf(&content, "- `%s`\n", m.Signature)
		}
	}

	metadata := map[string]interface{}{
		"package":        pkg.Name,
		"qualified_name": class.QualifiedName,
		"kind":           string(class.Kind),
		"doc_url":        class.DocURL,
	}

	return &Document{
		ID:        generateDocID(class.DocURL),
		Source:    sourceName,
		Type:      "java-class",
		Title:     class.QualifiedName,
		Content:   content.String(),
		URL:       class.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}

func (s *JavaDocsScraper) interfaceToDocument(iface *javadocs.Class, pkg *javadocs.Package, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s (interface)\n\n", iface.QualifiedName)
	fmt.Fprintf(&content, "%s\n", iface.Doc)

	metadata := map[string]interface{}{
		"package":        pkg.Name,
		"qualified_name": iface.QualifiedName,
		"kind":           "interface",
		"doc_url":        iface.DocURL,
	}

	return &Document{
		ID:        generateDocID(iface.DocURL),
		Source:    sourceName,
		Type:      "java-interface",
		Title:     iface.QualifiedName,
		Content:   content.String(),
		URL:       iface.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}

func (s *JavaDocsScraper) enumToDocument(enum *javadocs.Enum, pkg *javadocs.Package, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s (enum)\n\n", enum.QualifiedName)
	fmt.Fprintf(&content, "%s\n", enum.Doc)

	if len(enum.Constants) > 0 {
		fmt.Fprintf(&content, "\n## Constants\n")
		for _, c := range enum.Constants {
			fmt.Fprintf(&content, "- `%s`\n", c.Name)
		}
	}

	metadata := map[string]interface{}{
		"package":        pkg.Name,
		"qualified_name": enum.QualifiedName,
		"kind":           "enum",
		"doc_url":        enum.DocURL,
	}

	return &Document{
		ID:        generateDocID(enum.DocURL),
		Source:    sourceName,
		Type:      "java-enum",
		Title:     enum.QualifiedName,
		Content:   content.String(),
		URL:       enum.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}

func (s *JavaDocsScraper) exceptionToDocument(exc *javadocs.Class, pkg *javadocs.Package, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s (exception)\n\n", exc.QualifiedName)
	fmt.Fprintf(&content, "%s\n", exc.Doc)

	metadata := map[string]interface{}{
		"package":        pkg.Name,
		"qualified_name": exc.QualifiedName,
		"kind":           "exception",
		"doc_url":        exc.DocURL,
	}

	return &Document{
		ID:        generateDocID(exc.DocURL),
		Source:    sourceName,
		Type:      "java-exception",
		Title:     exc.QualifiedName,
		Content:   content.String(),
		URL:       exc.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}