package scraper

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

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

type VueDocsScraper struct {
	config *Config
	parser *vuedocs.Parser
	client *http.Client
}

func NewVueDocsScraper(config *Config) *VueDocsScraper {
	return &VueDocsScraper{
		config: config,
		parser: vuedocs.NewParser(),
		client: &http.Client{
			Timeout: config.Timeout,
		},
	}
}

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

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

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

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

	mainDoc := s.referenceToDocument(ref, source.Name)
	documents = append(documents, mainDoc)

	for _, comp := range ref.Composition {
		doc := s.compositionToDocument(comp, source.Name)
		documents = append(documents, doc)
	}

	for _, dir := range ref.Directives {
		doc := s.directiveToDocument(dir, source.Name)
		documents = append(documents, doc)
	}

	for _, comp := range ref.Components {
		doc := s.componentToDocument(comp, source.Name)
		documents = append(documents, doc)
	}

	for _, api := range ref.GlobalAPI {
		doc := s.globalAPIToDocument(api, source.Name)
		documents = append(documents, doc)
	}

	return documents, nil
}

func (s *VueDocsScraper) 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 *VueDocsScraper) fetchPage(ctx context.Context, url string) (string, error) {
	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
	if err != nil {
		return "", err
	}

	req.Header.Set("User-Agent", s.config.UserAgent)

	resp, err := s.client.Do(req)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("HTTP %d", resp.StatusCode)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}
	return string(body), nil
}

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

func (s *VueDocsScraper) referenceToDocument(ref *vuedocs.Reference, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# Vue API Reference\n\n")
	fmt.Fprintf(&content, "Composition API: %d, Directives: %d, Components: %d\n", len(ref.Composition), len(ref.Directives), len(ref.Components))

	return &Document{
		ID:        generateDocID(ref.DocURL),
		Source:    sourceName,
		Type:      "vue-reference",
		Title:     "Vue API Reference",
		Content:   content.String(),
		URL:       ref.DocURL,
		Metadata:  map[string]interface{}{"doc_type": "vue-reference"},
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}

func (s *VueDocsScraper) compositionToDocument(comp *vuedocs.Composition, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s\n\n", comp.Name)
	if comp.Signature != "" {
		fmt.Fprintf(&content, "```javascript\n%s\n```\n\n", comp.Signature)
	}
	fmt.Fprintf(&content, "%s\n", comp.Doc)

	metadata := map[string]interface{}{
		"name":     comp.Name,
		"kind":     comp.Kind,
		"doc_url":  comp.DocURL,
		"doc_type": "vue-composition",
	}

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

func (s *VueDocsScraper) directiveToDocument(dir *vuedocs.Directive, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s\n\n", dir.Name)
	fmt.Fprintf(&content, "%s\n", dir.Doc)

	metadata := map[string]interface{}{
		"name":     dir.Name,
		"doc_url":  dir.DocURL,
		"doc_type": "vue-directive",
	}

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

func (s *VueDocsScraper) componentToDocument(comp *vuedocs.Component, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# <%s />\n\n", comp.Name)
	fmt.Fprintf(&content, "%s\n", comp.Doc)

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

	metadata := map[string]interface{}{
		"name":     comp.Name,
		"doc_url":  comp.DocURL,
		"doc_type": "vue-component",
	}

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

func (s *VueDocsScraper) globalAPIToDocument(api *vuedocs.API, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s\n\n", api.Name)
	if api.Signature != "" {
		fmt.Fprintf(&content, "```javascript\n%s\n```\n\n", api.Signature)
	}
	fmt.Fprintf(&content, "%s\n", api.Doc)

	metadata := map[string]interface{}{
		"name":     api.Name,
		"category": api.Category,
		"doc_url":  api.DocURL,
		"doc_type": "vue-api",
	}

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