package scraper

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

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

type PythonDocsScraper struct {
	config *Config
	parser *pythondocs.Parser
	client *http.Client
}

func NewPythonDocsScraper(config *Config) *PythonDocsScraper {
	return &PythonDocsScraper{
		config: config,
		parser: pythondocs.NewParser(),
		client: &http.Client{
			Timeout: config.Timeout,
		},
	}
}

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

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

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

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

	mainDoc := s.moduleToDocument(module, source.Name)
	documents = append(documents, mainDoc)

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

		for _, method := range class.Methods {
			methodDoc := s.methodToDocument(method, class, module, source.Name)
			documents = append(documents, methodDoc)
		}

		for _, method := range class.ClassMethods {
			methodDoc := s.classMethodToDocument(method, class, module, source.Name)
			documents = append(documents, methodDoc)
		}

		for _, attr := range class.Attributes {
			attrDoc := s.attributeToDocument(attr, class, module, source.Name)
			documents = append(documents, attrDoc)
		}
	}

	for _, fn := range module.Functions {
		doc := s.functionToDocument(fn, module, source.Name)
		documents = append(documents, doc)
	}

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

	for _, data := range module.Constants {
		doc := s.dataToDocument(data, module, source.Name)
		documents = append(documents, doc)
	}

	return documents, nil
}

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

func (s *PythonDocsScraper) moduleToDocument(module *pythondocs.Module, sourceName string) *Document {
	content := s.buildModuleContent(module)

	metadata := map[string]interface{}{
		"name":            module.Name,
		"path":            module.Path,
		"version":         module.Version,
		"doc_url":         module.DocURL,
		"class_count":     len(module.Classes),
		"function_count":  len(module.Functions),
		"exception_count": len(module.Exceptions),
		"data_count":      len(module.Constants),
	}

	return &Document{
		ID:        generateDocID(module.DocURL),
		Source:    sourceName,
		Type:      "python-module",
		Title:     fmt.Sprintf("%s - Python", module.Name),
		Content:   content,
		URL:       module.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content),
		Timestamp: time.Now(),
	}
}

func (s *PythonDocsScraper) buildModuleContent(module *pythondocs.Module) string {
	var parts []string

	parts = append(parts, fmt.Sprintf("# Module %s\n", module.Name))

	if module.Synopsis != "" {
		parts = append(parts, module.Synopsis)
	}

	if module.Doc != "" {
		parts = append(parts, "\n"+module.Doc)
	}

	if len(module.Classes) > 0 {
		parts = append(parts, fmt.Sprintf("\n## Classes (%d)\n", len(module.Classes)))
		for _, class := range module.Classes {
			parts = append(parts, fmt.Sprintf("- `%s`", class.Name))
		}
	}

	if len(module.Functions) > 0 {
		parts = append(parts, fmt.Sprintf("\n## Functions (%d)\n", len(module.Functions)))
		for _, fn := range module.Functions {
			parts = append(parts, fmt.Sprintf("- `%s`", fn.Name))
		}
	}

	if len(module.Exceptions) > 0 {
		parts = append(parts, fmt.Sprintf("\n## Exceptions (%d)\n", len(module.Exceptions)))
		for _, exc := range module.Exceptions {
			parts = append(parts, fmt.Sprintf("- `%s`", exc.Name))
		}
	}

	return strings.Join(parts, "\n")
}

func (s *PythonDocsScraper) classToDocument(class *pythondocs.Class, module *pythondocs.Module, sourceName string) *Document {
	content := s.buildClassContent(class, module)

	metadata := map[string]interface{}{
		"module":          module.Name,
		"class":           class.Name,
		"qual_name":       class.QualName,
		"bases":           class.Bases,
		"method_count":    len(class.Methods),
		"attribute_count": len(class.Attributes),
	}

	return &Document{
		ID:        generateDocID(class.DocURL),
		Source:    sourceName,
		Type:      "python-class",
		Title:     fmt.Sprintf("%s.%s - Python", module.Name, class.Name),
		Content:   content,
		URL:       class.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content),
		Timestamp: time.Now(),
	}
}

func (s *PythonDocsScraper) buildClassContent(class *pythondocs.Class, module *pythondocs.Module) string {
	var parts []string

	parts = append(parts, fmt.Sprintf("# class %s.%s\n", module.Name, class.Name))

	if class.Signature != "" {
		parts = append(parts, fmt.Sprintf("```python\n%s\n```", class.Signature))
	}

	if class.Doc != "" {
		parts = append(parts, "\n"+class.Doc)
	}

	if len(class.Bases) > 0 {
		parts = append(parts, fmt.Sprintf("\n**Bases:** %s\n", strings.Join(class.Bases, ", ")))
	}

	if len(class.Methods) > 0 {
		parts = append(parts, fmt.Sprintf("\n### Methods (%d)\n", len(class.Methods)))
		for _, m := range class.Methods {
			parts = append(parts, fmt.Sprintf("- `%s`", m.Name))
		}
	}

	if len(class.ClassMethods) > 0 {
		parts = append(parts, fmt.Sprintf("\n### Class Methods (%d)\n", len(class.ClassMethods)))
		for _, m := range class.ClassMethods {
			parts = append(parts, fmt.Sprintf("- `%s` (classmethod)", m.Name))
		}
	}

	if len(class.Attributes) > 0 {
		parts = append(parts, fmt.Sprintf("\n### Attributes (%d)\n", len(class.Attributes)))
		for _, a := range class.Attributes {
			parts = append(parts, fmt.Sprintf("- `%s`", a.Name))
		}
	}

	return strings.Join(parts, "\n")
}

func (s *PythonDocsScraper) methodToDocument(method *pythondocs.Method, class *pythondocs.Class, module *pythondocs.Module, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s.%s.%s\n\n", module.Name, class.Name, method.Name)

	if method.Signature != "" {
		fmt.Fprintf(&content, "```python\n%s\n```\n", method.Signature)
	}

	if method.Doc != "" {
		fmt.Fprintf(&content, "%s\n", method.Doc)
	}

	metadata := map[string]interface{}{
		"module":    module.Name,
		"class":     class.Name,
		"method":    method.Name,
		"qual_name": method.QualName,
		"is_static": method.IsStatic,
		"is_async":  method.IsAsync,
	}

	return &Document{
		ID:        generateDocID(method.DocURL),
		Source:    sourceName,
		Type:      "python-method",
		Title:     fmt.Sprintf("%s.%s.%s - Python", module.Name, class.Name, method.Name),
		Content:   content.String(),
		URL:       method.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}

func (s *PythonDocsScraper) classMethodToDocument(method *pythondocs.Method, class *pythondocs.Class, module *pythondocs.Module, sourceName string) *Document {
	content := s.buildMethodContent(method, class, module)

	metadata := map[string]interface{}{
		"module":         module.Name,
		"class":          class.Name,
		"method":         method.Name,
		"qual_name":      method.QualName,
		"is_classmethod": true,
	}

	return &Document{
		ID:        generateDocID(method.DocURL),
		Source:    sourceName,
		Type:      "python-classmethod",
		Title:     fmt.Sprintf("%s.%s.%s (classmethod) - Python", module.Name, class.Name, method.Name),
		Content:   content,
		URL:       method.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content),
		Timestamp: time.Now(),
	}
}

func (s *PythonDocsScraper) buildMethodContent(method *pythondocs.Method, class *pythondocs.Class, module *pythondocs.Module) string {
	var parts []string

	parts = append(parts, fmt.Sprintf("# %s.%s.%s\n", module.Name, class.Name, method.Name))

	if method.Signature != "" {
		parts = append(parts, fmt.Sprintf("```python\n%s\n```", method.Signature))
	}

	if method.Doc != "" {
		parts = append(parts, "\n"+method.Doc)
	}

	return strings.Join(parts, "\n")
}

func (s *PythonDocsScraper) attributeToDocument(attr *pythondocs.Attribute, class *pythondocs.Class, module *pythondocs.Module, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s.%s.%s\n\n", module.Name, class.Name, attr.Name)

	if attr.Doc != "" {
		fmt.Fprintf(&content, "%s\n", attr.Doc)
	}

	metadata := map[string]interface{}{
		"module": module.Name,
		"class":  class.Name,
		"attr":   attr.Name,
		"type":   attr.Type,
	}

	return &Document{
		ID:        generateDocID(attr.DocURL),
		Source:    sourceName,
		Type:      "python-attribute",
		Title:     fmt.Sprintf("%s.%s.%s - Python", module.Name, class.Name, attr.Name),
		Content:   content.String(),
		URL:       attr.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}

func (s *PythonDocsScraper) functionToDocument(fn *pythondocs.Function, module *pythondocs.Module, sourceName string) *Document {
	content := s.buildFunctionContent(fn, module)

	metadata := map[string]interface{}{
		"module":       module.Name,
		"function":     fn.Name,
		"qual_name":    fn.QualName,
		"signature":    fn.Signature,
		"is_async":     fn.IsAsync,
		"is_generator": fn.IsGenerator,
	}

	return &Document{
		ID:        generateDocID(fn.DocURL),
		Source:    sourceName,
		Type:      "python-function",
		Title:     fmt.Sprintf("%s.%s - Python", module.Name, fn.Name),
		Content:   content,
		URL:       fn.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content),
		Timestamp: time.Now(),
	}
}

func (s *PythonDocsScraper) buildFunctionContent(fn *pythondocs.Function, module *pythondocs.Module) string {
	var parts []string

	parts = append(parts, fmt.Sprintf("# %s.%s\n", module.Name, fn.Name))

	if fn.Signature != "" {
		parts = append(parts, fmt.Sprintf("```python\n%s\n```", fn.Signature))
	}

	if fn.Doc != "" {
		parts = append(parts, "\n"+fn.Doc)
	}

	return strings.Join(parts, "\n")
}

func (s *PythonDocsScraper) exceptionToDocument(exc *pythondocs.Exception, module *pythondocs.Module, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s.%s\n\n", module.Name, exc.Name)

	if exc.Signature != "" {
		fmt.Fprintf(&content, "```python\n%s\n```\n", exc.Signature)
	}

	if exc.Doc != "" {
		fmt.Fprintf(&content, "%s\n", exc.Doc)
	}

	metadata := map[string]interface{}{
		"module":    module.Name,
		"exception": exc.Name,
		"qual_name": exc.QualName,
		"bases":     exc.Bases,
	}

	return &Document{
		ID:        generateDocID(exc.DocURL),
		Source:    sourceName,
		Type:      "python-exception",
		Title:     fmt.Sprintf("%s.%s - Python", module.Name, exc.Name),
		Content:   content.String(),
		URL:       exc.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}

func (s *PythonDocsScraper) dataToDocument(data *pythondocs.Data, module *pythondocs.Module, sourceName string) *Document {
	var content strings.Builder
	fmt.Fprintf(&content, "# %s.%s\n\n", module.Name, data.Name)

	if data.Doc != "" {
		fmt.Fprintf(&content, "%s\n", data.Doc)
	}

	metadata := map[string]interface{}{
		"module": module.Name,
		"data":   data.Name,
		"type":   data.Type,
		"value":  data.Value,
	}

	return &Document{
		ID:        generateDocID(data.DocURL),
		Source:    sourceName,
		Type:      "python-data",
		Title:     fmt.Sprintf("%s.%s - Python", module.Name, data.Name),
		Content:   content.String(),
		URL:       data.DocURL,
		Metadata:  metadata,
		Hash:      s.generateHash(content.String()),
		Timestamp: time.Now(),
	}
}