package scraper

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

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

type NuxtDocsScraper struct {
	config *Config
	parser *nuxtdocs.Parser
	client *http.Client
}

func NewNuxtDocsScraper(config *Config) *NuxtDocsScraper {
	return &NuxtDocsScraper{
		config: config,
		parser: nuxtdocs.NewParser(),
		client: &http.Client{
			Timeout: config.Timeout,
		},
	}
}

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

	if source.URL == "" {
		return nil, fmt.Errorf("URL is required for Nuxt 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.Components {
		doc := s.componentToDocument(comp, source.Name)
		documents = append(documents, doc)
	}

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

	for _, util := range ref.Utilities {
		doc := s.utilityToDocument(util, source.Name)
		documents = append(documents, doc)
	}

	for _, cfg := range ref.Configs {
		doc := s.configToDocument(cfg, source.Name)
		documents = append(documents, doc)
	}

	for _, cmd := range ref.Commands {
		doc := s.commandToDocument(cmd, source.Name)
		documents = append(documents, doc)
	}

	return documents, nil
}

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

func (s *NuxtDocsScraper) referenceToDocument(ref *nuxtdocs.Reference, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# Nuxt API Reference\n\n")
	fmt.Fprintf(&content, "Components: %d, Composables: %d, Utilities: %d, Configs: %d, Commands: %d\n",
		len(ref.Components), len(ref.Composables), len(ref.Utilities), len(ref.Configs), len(ref.Commands))

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

func (s *NuxtDocsScraper) componentToDocument(comp *nuxtdocs.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,
		"category": comp.Category,
		"doc_url":  comp.DocURL,
		"doc_type": "nuxt-component",
	}

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

func (s *NuxtDocsScraper) composableToDocument(comp *nuxtdocs.Composable, 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)

	if comp.Returns != "" {
		fmt.Fprintf(&content, "\n**Returns:** `%s`\n", comp.Returns)
	}

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

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

func (s *NuxtDocsScraper) utilityToDocument(util *nuxtdocs.Utility, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s\n\n", util.Name)
	if util.Signature != "" {
		fmt.Fprintf(&content, "```javascript\n%s\n```\n\n", util.Signature)
	}
	fmt.Fprintf(&content, "%s\n", util.Doc)

	metadata := map[string]interface{}{
		"name":     util.Name,
		"doc_url":  util.DocURL,
		"doc_type": "nuxt-utility",
	}

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

func (s *NuxtDocsScraper) configToDocument(cfg *nuxtdocs.Config, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s\n\n", cfg.Name)
	if cfg.Type != "" {
		fmt.Fprintf(&content, "Type: `%s`\n\n", cfg.Type)
	}
	if cfg.Default != "" {
		fmt.Fprintf(&content, "Default: `%s`\n\n", cfg.Default)
	}
	fmt.Fprintf(&content, "%s\n", cfg.Doc)

	metadata := map[string]interface{}{
		"name":     cfg.Name,
		"type":     cfg.Type,
		"default":  cfg.Default,
		"category": cfg.Category,
		"doc_url":  cfg.DocURL,
		"doc_type": "nuxt-config",
	}

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

func (s *NuxtDocsScraper) commandToDocument(cmd *nuxtdocs.Command, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s\n\n", cmd.Name)
	if cmd.Usage != "" {
		fmt.Fprintf(&content, "```\n%s\n```\n\n", cmd.Usage)
	}
	fmt.Fprintf(&content, "%s\n", cmd.Doc)

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

	metadata := map[string]interface{}{
		"name":     cmd.Name,
		"usage":    cmd.Usage,
		"doc_url":  cmd.DocURL,
		"doc_type": "nuxt-command",
	}

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