package generator

import (
	"bytes"
	"encoding/json"
	"fmt"
	"html/template"
	"path/filepath"
	"time"

	"gitcitadel-online/internal/asciidoc"
	"gitcitadel-online/internal/nostr"
)

// HTMLGenerator generates HTML pages from wiki events
type HTMLGenerator struct {
	templates    *template.Template
	templateDir  string
	asciidocProc *asciidoc.Processor
	linkBaseURL  string
	siteName     string
	siteURL      string
	defaultImage string
}

// PageData represents data for a wiki page
type PageData struct {
	Title           string
	Description     string
	Keywords        string
	CanonicalURL    string
	OGImage         string
	OGType          string
	StructuredData  template.JS
	SiteName        string
	SiteURL         string
	CurrentYear     int
	WikiPages       []WikiPageInfo
	BlogItems       []BlogItemInfo
	BlogSummary     string
	FeedItems       []FeedItemInfo
	EBooks          []EBookInfo
	Content         template.HTML
	Summary         string
	TableOfContents template.HTML
}

// WikiPageInfo represents info about a wiki page for navigations
type WikiPageInfo struct {
	DTag  string
	Title string
}

// BlogItemInfo represents info about a blog item
type BlogItemInfo struct {
	DTag      string
	Title     string
	Summary   string
	Content   template.HTML
	Author    string
	CreatedAt int64
	Time      string // Formatted time
	TimeISO   string // ISO time
}

// FeedItemInfo represents info about a feed item
type FeedItemInfo struct {
	Author  string
	Content string
	Time    string
	TimeISO string
	Link    string
}

// EBookInfo represents info about an e-book (top-level index event)
type EBookInfo struct {
	EventID   string
	Title     string
	DTag      string
	Author    string
	Summary   string
	Type      string
	CreatedAt int64
	Naddr     string
	Time      string // Formatted time
	TimeISO   string // ISO time
}

// NewHTMLGenerator creates a new HTML generator
func NewHTMLGenerator(templateDir string, linkBaseURL, siteName, siteURL, defaultImage string) (*HTMLGenerator, error) {
	tmpl := template.New("base").Funcs(template.FuncMap{
		"year": func() int { return time.Now().Year() },
		"json": func(v interface{}) (string, error) {
			b, err := json.Marshal(v)
			if err != nil {
				return "", err
			}
			return string(b), nil
		},
		"hasPrefix": func(s, prefix string) bool {
			return len(s) >= len(prefix) && s[:len(prefix)] == prefix
		},
	})

	// Load all templates
	templateFiles := []string{
		"components.html", // Reusable components (feed, alerts, etc.)
		"base.html",
		"landing.html",
		"page.html",
		"blog.html",
		"wiki.html",
		"contact.html",
		"404.html",
		"500.html",
	}

	for _, file := range templateFiles {
		path := filepath.Join(templateDir, file)
		_, err := tmpl.ParseFiles(path)
		if err != nil {
			return nil, err
		}
	}

	return &HTMLGenerator{
		templates:    tmpl,
		templateDir:  templateDir,
		asciidocProc: asciidoc.NewProcessor(linkBaseURL),
		linkBaseURL:  linkBaseURL,
		siteName:     siteName,
		siteURL:      siteURL,
		defaultImage: defaultImage,
	}, nil
}

// ProcessAsciiDoc processes AsciiDoc content to HTML
func (g *HTMLGenerator) ProcessAsciiDoc(content string) (string, error) {
	return g.asciidocProc.Process(content)
}

// GenerateLandingPage generates the static landing page
func (g *HTMLGenerator) GenerateLandingPage(wikiPages []WikiPageInfo, feedItems []FeedItemInfo) (string, error) {
	data := PageData{
		Title:        "Home",
		Description:  "Welcome to " + g.siteName,
		CanonicalURL: g.siteURL + "/",
		OGImage:      g.siteURL + g.defaultImage,
		OGType:       "website",
		SiteName:     g.siteName,
		SiteURL:      g.siteURL,
		CurrentYear:  time.Now().Year(),
		WikiPages:    wikiPages,
		FeedItems:    feedItems,
	}

	return g.renderTemplate("landing.html", data)
}

// GenerateWikiPage generates a wiki article page
func (g *HTMLGenerator) GenerateWikiPage(wiki *nostr.WikiEvent, wikiPages []WikiPageInfo, feedItems []FeedItemInfo) (string, error) {
	// Process AsciiDoc content
	htmlContent, err := g.asciidocProc.Process(wiki.Content)
	if err != nil {
		return "", err
	}

	description := wiki.Summary
	if description == "" {
		description = wiki.Title
	}

	canonicalURL := g.siteURL + "/wiki/" + wiki.DTag

	data := PageData{
		Title:        wiki.Title,
		Description:  description,
		CanonicalURL: canonicalURL,
		OGImage:      g.siteURL + g.defaultImage,
		OGType:       "article",
		SiteName:     g.siteName,
		SiteURL:      g.siteURL,
		CurrentYear:  time.Now().Year(),
		WikiPages:    wikiPages,
		FeedItems:    []FeedItemInfo{}, // Empty - feed only on landing page
		Content:      template.HTML(htmlContent),
		Summary:      wiki.Summary,
	}

	// Add structured data for article
	data.StructuredData = template.JS(g.generateArticleStructuredData(wiki, canonicalURL))

	return g.renderTemplate("page.html", data)
}

// GenerateBlogPage generates the blog index page
func (g *HTMLGenerator) GenerateBlogPage(blogIndex *nostr.IndexEvent, blogItems []BlogItemInfo, feedItems []FeedItemInfo) (string, error) {
	description := blogIndex.Summary
	if description == "" {
		description = "Blog articles from " + g.siteName
	}

	canonicalURL := g.siteURL + "/blog"

	// Format times for blog items
	formattedBlogItems := make([]BlogItemInfo, len(blogItems))
	for i, item := range blogItems {
		formattedBlogItems[i] = item
		if item.CreatedAt > 0 {
			createdTime := time.Unix(item.CreatedAt, 0)
			formattedBlogItems[i].Time = createdTime.Format("Jan 2, 2006")
			formattedBlogItems[i].TimeISO = createdTime.Format(time.RFC3339)
		}
	}

	data := PageData{
		Title:        "Blog",
		Description:  description,
		CanonicalURL: canonicalURL,
		OGImage:      g.siteURL + g.defaultImage,
		OGType:       "website",
		SiteName:     g.siteName,
		SiteURL:      g.siteURL,
		CurrentYear:  time.Now().Year(),
		BlogItems:    formattedBlogItems,
		BlogSummary:  blogIndex.Summary,
		FeedItems:    []FeedItemInfo{}, // Empty - feed only on landing page
		Content:      template.HTML(""),
	}

	// Add blog index metadata to template data using a map
	type BlogPageData struct {
		PageData
		BlogIndexTitle   string
		BlogIndexAuthor  string
		BlogIndexImage   string
		BlogIndexSummary string
	}

	blogData := BlogPageData{
		PageData:         data,
		BlogIndexTitle:   blogIndex.Title,
		BlogIndexAuthor:  blogIndex.Author,
		BlogIndexImage:   blogIndex.Image,
		BlogIndexSummary: blogIndex.Summary,
	}

	// Use renderTemplate but with custom data
	renderTmpl := template.New("blog-render").Funcs(template.FuncMap{
		"year": func() int { return time.Now().Year() },
		"json": func(v interface{}) (string, error) {
			b, err := json.Marshal(v)
			if err != nil {
				return "", err
			}
			return string(b), nil
		},
		"hasPrefix": func(s, prefix string) bool {
			return len(s) >= len(prefix) && s[:len(prefix)] == prefix
		},
	})

	files := []string{
		filepath.Join(g.templateDir, "components.html"),
		filepath.Join(g.templateDir, "base.html"),
		filepath.Join(g.templateDir, "blog.html"),
	}

	_, err := renderTmpl.ParseFiles(files...)
	if err != nil {
		return "", fmt.Errorf("failed to parse blog templates: %w", err)
	}

	var buf bytes.Buffer
	if err := renderTmpl.ExecuteTemplate(&buf, "base.html", blogData); err != nil {
		return "", fmt.Errorf("failed to execute blog template: %w", err)
	}

	return buf.String(), nil
}

// GenerateWikiIndexPage generates the wiki index page
func (g *HTMLGenerator) GenerateWikiIndexPage(wikiIndex *nostr.IndexEvent, wikiPages []WikiPageInfo, feedItems []FeedItemInfo) (string, error) {
	description := "Wiki documentation from " + g.siteName
	summary := ""

	if wikiIndex != nil {
		if wikiIndex.Summary != "" {
			description = wikiIndex.Summary
			summary = wikiIndex.Summary
		}
	}

	canonicalURL := g.siteURL + "/wiki"

	data := PageData{
		Title:        "Wiki",
		Description:  description,
		CanonicalURL: canonicalURL,
		OGImage:      g.siteURL + g.defaultImage,
		OGType:       "website",
		SiteName:     g.siteName,
		SiteURL:      g.siteURL,
		CurrentYear:  time.Now().Year(),
		WikiPages:    wikiPages,
		FeedItems:    []FeedItemInfo{}, // Empty - feed only on landing page
		Summary:      summary,
	}

	return g.renderTemplate("wiki.html", data)
}

// GenerateEBooksPage generates the e-books listing page
func (g *HTMLGenerator) GenerateEBooksPage(ebooks []EBookInfo, feedItems []FeedItemInfo) (string, error) {
	canonicalURL := g.siteURL + "/ebooks"

	// Format times for display
	formattedEBooks := make([]EBookInfo, len(ebooks))
	for i, ebook := range ebooks {
		formattedEBooks[i] = ebook
		createdTime := time.Unix(ebook.CreatedAt, 0)
		formattedEBooks[i].Time = createdTime.Format("2006-01-02 15:04:05")
		formattedEBooks[i].TimeISO = createdTime.Format(time.RFC3339)
	}

	data := PageData{
		Title:        "E-Books",
		Description:  "Browse top-level publications (index events) from Nostr",
		CanonicalURL: canonicalURL,
		OGImage:      g.siteURL + g.defaultImage,
		OGType:       "website",
		SiteName:     g.siteName,
		SiteURL:      g.siteURL,
		CurrentYear:  time.Now().Year(),
		WikiPages:    []WikiPageInfo{},
		FeedItems:    []FeedItemInfo{}, // Empty - feed only on landing page
		EBooks:       formattedEBooks,
		Content:      template.HTML(""), // Content comes from template
	}

	return g.renderTemplate("ebooks.html", data)
}

// GenerateContactPage generates the contact form page
func (g *HTMLGenerator) GenerateContactPage(success bool, errorMsg string, eventID string, formData map[string]string, repoAnnouncement *nostr.RepoAnnouncement, feedItems []FeedItemInfo) (string, error) {
	// Prepare form data with defaults
	subject := ""
	content := ""
	labels := ""
	if formData != nil {
		subject = formData["subject"]
		content = formData["content"]
		labels = formData["labels"]
	}

	// Create form data struct for template
	type ContactFormData struct {
		Subject string
		Content string
		Labels  string
	}

	type ContactPageData struct {
		PageData
		Success  bool
		Error    string
		EventID  string
		FormData ContactFormData
	}

	data := ContactPageData{
		PageData: PageData{
			Title:        "Contact",
			Description:  "Contact " + g.siteName,
			CanonicalURL: g.siteURL + "/contact",
			OGImage:      g.siteURL + g.defaultImage,
			OGType:       "website",
			SiteName:     g.siteName,
			SiteURL:      g.siteURL,
			CurrentYear:  time.Now().Year(),
			WikiPages:    []WikiPageInfo{}, // Will be populated if needed
			FeedItems:    []FeedItemInfo{}, // Empty - feed only on landing page
		},
		Success: success,
		Error:   errorMsg,
		EventID: eventID,
		FormData: ContactFormData{
			Subject: subject,
			Content: content,
			Labels:  labels,
		},
	}

	// Parse base.html together with contact.html to ensure correct blocks are used
	renderTmpl := template.New("render").Funcs(template.FuncMap{
		"year": func() int { return time.Now().Year() },
		"json": func(v interface{}) (string, error) {
			b, err := json.Marshal(v)
			if err != nil {
				return "", err
			}
			return string(b), nil
		},
		"hasPrefix": func(s, prefix string) bool {
			return len(s) >= len(prefix) && s[:len(prefix)] == prefix
		},
	})

	// Parse base.html, components.html, and contact.html together
	files := []string{
		filepath.Join(g.templateDir, "components.html"), // Reusable components
		filepath.Join(g.templateDir, "base.html"),
		filepath.Join(g.templateDir, "contact.html"),
	}

	_, err := renderTmpl.ParseFiles(files...)
	if err != nil {
		return "", fmt.Errorf("failed to parse templates: %w", err)
	}

	// Create a map that includes both PageData fields and contact-specific fields
	templateData := map[string]interface{}{
		"Title":        data.Title,
		"Description":  data.Description,
		"CanonicalURL": data.CanonicalURL,
		"OGImage":      data.OGImage,
		"OGType":       data.OGType,
		"SiteName":     data.SiteName,
		"SiteURL":      data.SiteURL,
		"CurrentYear":  data.CurrentYear,
		"WikiPages":    data.WikiPages,
		"BlogItems":    data.BlogItems,
		"FeedItems":    []FeedItemInfo{}, // Empty - feed only on landing page
		"Success":      data.Success,
		"Error":        data.Error,
		"EventID":      data.EventID,
		"FormData":     data.FormData,
	}

	// Add repo announcement data for JavaScript
	if repoAnnouncement != nil {
		templateData["RepoAnnouncement"] = map[string]interface{}{
			"Pubkey":      repoAnnouncement.Pubkey,
			"DTag":        repoAnnouncement.DTag,
			"Relays":      repoAnnouncement.Relays,
			"Maintainers": repoAnnouncement.Maintainers,
		}
	}

	// Execute base.html which will use the blocks from contact.html
	var buf bytes.Buffer
	if err := renderTmpl.ExecuteTemplate(&buf, "base.html", templateData); err != nil {
		return "", fmt.Errorf("failed to execute base template: %w", err)
	}

	return buf.String(), nil
}

// GenerateErrorPage generates an error page (404 or 500) using base.html
func (g *HTMLGenerator) GenerateErrorPage(statusCode int, feedItems []FeedItemInfo) (string, error) {
	var title, message string
	switch statusCode {
	case 404:
		title = "404 - Page Not Found"
		message = "The page you're looking for doesn't exist."
	case 500:
		title = "500 - Server Error"
		message = "Something went wrong on our end. Please try again later."
	default:
		title = "Error"
		message = "An error occurred."
	}

	canonicalURL := g.siteURL
	switch statusCode {
	case 404:
		canonicalURL = g.siteURL + "/404"
	case 500:
		canonicalURL = g.siteURL + "/500"
	}

	data := PageData{
		Title:        title,
		Description:  message,
		CanonicalURL: canonicalURL,
		OGImage:      g.siteURL + g.defaultImage,
		OGType:       "website",
		SiteName:     g.siteName,
		SiteURL:      g.siteURL,
		CurrentYear:  time.Now().Year(),
		WikiPages:    []WikiPageInfo{},
		FeedItems:    []FeedItemInfo{},  // Empty - feed only on landing page
		Content:      template.HTML(""), // Content will come from the template
	}

	return g.renderTemplate(fmt.Sprintf("%d.html", statusCode), data)
}

// renderTemplate renders a template with the base template
func (g *HTMLGenerator) renderTemplate(templateName string, data PageData) (string, error) {
	// Parse base.html together with the specific template to ensure correct blocks are used
	// This avoids the issue where all templates are parsed together and the last "content" block wins
	renderTmpl := template.New("render").Funcs(template.FuncMap{
		"year": func() int { return time.Now().Year() },
		"json": func(v interface{}) (string, error) {
			b, err := json.Marshal(v)
			if err != nil {
				return "", err
			}
			return string(b), nil
		},
		"hasPrefix": func(s, prefix string) bool {
			return len(s) >= len(prefix) && s[:len(prefix)] == prefix
		},
	})

	// Parse base.html, components.html, and the specific template together
	// This ensures the correct "content" block and reusable components are available
	files := []string{
		filepath.Join(g.templateDir, "components.html"), // Reusable components
		filepath.Join(g.templateDir, "base.html"),
		filepath.Join(g.templateDir, templateName),
	}

	_, err := renderTmpl.ParseFiles(files...)
	if err != nil {
		return "", fmt.Errorf("failed to parse templates: %w", err)
	}

	// Execute base.html which will use the blocks from templateName
	var buf bytes.Buffer
	if err := renderTmpl.ExecuteTemplate(&buf, "base.html", data); err != nil {
		return "", fmt.Errorf("failed to execute base template: %w", err)
	}

	return buf.String(), nil
}

// generateArticleStructuredData generates JSON-LD structured data for an article
func (g *HTMLGenerator) generateArticleStructuredData(wiki *nostr.WikiEvent, url string) string {
	// This is a simplified version - in production, use proper JSON encoding
	return `{
		"@context": "https://schema.org",
		"@type": "Article",
		"headline": "` + wiki.Title + `",
		"description": "` + wiki.Summary + `",
		"url": "` + url + `",
		"publisher": {
			"@type": "Organization",
			"name": "` + g.siteName + `"
		}
	}`
}