package cache

import (
	"context"
	"html/template"
	"time"

	"gitcitadel-online/internal/generator"
	"gitcitadel-online/internal/logger"
	"gitcitadel-online/internal/nostr"
)

// Rewarmer handles cache rewarming
type Rewarmer struct {
	cache         *Cache
	feedCache     *FeedCache
	wikiService   *nostr.WikiService
	feedService   *nostr.FeedService
	ebooksService *nostr.EBooksService
	htmlGenerator *generator.HTMLGenerator
	wikiIndex     string
	blogIndex     string
	feedRelay     string
	maxFeedEvents int
	interval      time.Duration
	feedInterval  time.Duration
}

// NewRewarmer creates a new cache rewarming service
func NewRewarmer(
	cache *Cache,
	feedCache *FeedCache,
	wikiService *nostr.WikiService,
	feedService *nostr.FeedService,
	ebooksService *nostr.EBooksService,
	htmlGenerator *generator.HTMLGenerator,
	wikiIndex, blogIndex, feedRelay string,
	maxFeedEvents int,
	interval, feedInterval time.Duration,
) *Rewarmer {
	return &Rewarmer{
		cache:         cache,
		feedCache:     feedCache,
		wikiService:   wikiService,
		feedService:   feedService,
		ebooksService: ebooksService,
		htmlGenerator: htmlGenerator,
		wikiIndex:     wikiIndex,
		blogIndex:     blogIndex,
		feedRelay:     feedRelay,
		maxFeedEvents: maxFeedEvents,
		interval:      interval,
		feedInterval:  feedInterval,
	}
}

// Start starts the rewarming goroutines
func (r *Rewarmer) Start(ctx context.Context) {
	// Initial population
	go r.rewarmPages(ctx)
	go r.rewarmFeed(ctx)

	// Periodic rewarming
	go r.periodicRewarmPages(ctx)
	go r.periodicRewarmFeed(ctx)
}

// rewarmPages rewarms the page cache
func (r *Rewarmer) rewarmPages(ctx context.Context) {
	logger.Info("Starting page cache rewarming...")

	// Initialize wikiPages as empty - will be populated if wiki fetch succeeds
	wikiPages := make([]generator.WikiPageInfo, 0)

	// Fetch wiki index (non-blocking - landing page can still be generated)
	// If theforest fails, leave pages as-is (don't remove existing events)
	wikiIndex, err := r.wikiService.FetchWikiIndex(ctx, r.wikiIndex)
	if err != nil {
		logger.Warnf("Error fetching wiki index from theforest: %v - keeping existing pages", err)
		// Don't update cache - leave existing pages as-is
		// Continue to generate landing page even if wiki fetch fails
	} else {
		// Fetch wiki events
		// If theforest fails, leave pages as-is (don't remove existing events)
		wikiEvents, err := r.wikiService.FetchWikiEvents(ctx, wikiIndex)
		if err != nil {
			logger.Warnf("Error fetching wiki events from theforest: %v - keeping existing pages", err)
			// Don't update cache - leave existing pages as-is
		} else {
			// Build wiki page info for navigation
			wikiPages = make([]generator.WikiPageInfo, 0, len(wikiEvents))
			for _, event := range wikiEvents {
				wikiPages = append(wikiPages, generator.WikiPageInfo{
					DTag:  event.DTag,
					Title: event.Title,
				})
			}

			// Generate and cache wiki index page
			wikiIndexHTML, err := r.htmlGenerator.GenerateWikiIndexPage(wikiIndex, wikiPages, []generator.FeedItemInfo{})
			if err != nil {
				logger.Errorf("Error generating wiki index page: %v", err)
			} else {
				if err := r.cache.Set("/wiki", wikiIndexHTML); err != nil {
					logger.Errorf("Error caching wiki index page: %v", err)
				} else {
					logger.WithField("pages", len(wikiPages)).Info("Wiki index page cached successfully")
				}
			}

			// Generate and cache wiki pages
			for _, event := range wikiEvents {
				html, err := r.htmlGenerator.GenerateWikiPage(event, wikiPages, []generator.FeedItemInfo{})
				if err != nil {
					logger.WithField("dtag", event.DTag).Errorf("Error generating wiki page: %v", err)
					continue
				}
				if err := r.cache.Set("/wiki/"+event.DTag, html); err != nil {
					logger.WithField("dtag", event.DTag).Errorf("Error caching wiki page: %v", err)
				}
			}
		}
	}

	// Fetch blog index if configured (needed for landing page)
	// If theforest fails, leave pages as-is (don't remove existing events)
	var newestBlogItem *generator.BlogItemInfo
	if r.blogIndex != "" {
		blogIndex, err := r.wikiService.FetchWikiIndex(ctx, r.blogIndex)
		if err != nil {
			logger.Warnf("Error fetching blog index from theforest: %v - keeping existing pages", err)
			// Don't update cache - leave existing pages as-is
		} else {
			// Fetch blog events using the generic FetchIndexEvents function
			// If theforest fails, leave pages as-is (don't remove existing events)
			blogKind := r.wikiService.GetBlogKind()
			blogEventList, err := r.wikiService.FetchIndexEvents(ctx, blogIndex, blogKind)
			if err != nil {
				logger.Warnf("Error fetching blog events from theforest: %v - keeping existing pages", err)
				// Don't update cache - leave existing pages as-is
			} else {
				logger.WithFields(map[string]interface{}{
					"events": len(blogEventList),
					"kind":   blogKind,
				}).Debug("Fetched blog events")
				blogItems := make([]generator.BlogItemInfo, 0, len(blogEventList))
				for _, event := range blogEventList {
					// Parse the blog event
					blog, err := nostr.ParseBlogEvent(event, blogKind)
					if err != nil {
						logger.WithField("event_id", event.ID).Warnf("Error parsing blog event: %v", err)
						continue
					}

					html, err := r.htmlGenerator.ProcessAsciiDoc(blog.Content)
					if err != nil {
						logger.WithField("dtag", blog.DTag).Warnf("Error processing blog content: %v", err)
						html = blog.Content // Fallback to raw content
					}
					blogItems = append(blogItems, generator.BlogItemInfo{
						DTag:      blog.DTag,
						Title:     blog.Title,
						Summary:   blog.Summary,
						Content:   template.HTML(html),
						Author:    event.PubKey,
						Image:     blog.Image,
						CreatedAt: int64(event.CreatedAt),
					})
				}
				logger.WithField("items", len(blogItems)).Debug("Generated blog items")

				// Get newest blog item for landing page
				if len(blogItems) > 0 {
					newestBlogItem = &blogItems[0]
				}

				// Generate blog page without feed items (feed only on landing page)
				blogHTML, err := r.htmlGenerator.GenerateBlogPage(blogIndex, blogItems, []generator.FeedItemInfo{})
				if err != nil {
					logger.Errorf("Error generating blog page: %v", err)
				} else {
					if err := r.cache.Set("/blog", blogHTML); err != nil {
						logger.Errorf("Error caching blog page: %v", err)
					} else {
						logger.WithField("items", len(blogItems)).Info("Blog page cached successfully")
					}
				}
			}
		}
	}

	// Fetch and cache articles page (longform articles) - needed for landing page
	// If theforest fails, leave pages as-is (don't remove existing events)
	var allArticleItems []generator.ArticleItemInfo
	var newestArticleItem *generator.ArticleItemInfo
	longformKind := r.wikiService.GetLongformKind()
	if longformKind > 0 {
		articleEvents, err := r.wikiService.FetchLongformArticles(ctx, "wss://theforest.nostr1.com", longformKind, 50)
		if err != nil {
			logger.Warnf("Error fetching longform articles from theforest: %v - keeping existing pages", err)
			// Don't update cache - leave existing pages as-is
		} else {
			articleItems := make([]generator.ArticleItemInfo, 0, len(articleEvents))
			for _, event := range articleEvents {
				// Parse the longform article
				article, err := nostr.ParseLongformEvent(event, longformKind)
				if err != nil {
					logger.WithField("event_id", event.ID).Warnf("Error parsing longform article: %v", err)
					continue
				}

				// Process markdown content
				html, err := r.htmlGenerator.ProcessMarkdown(article.Content)
				if err != nil {
					logger.WithField("dtag", article.DTag).Warnf("Error processing markdown content: %v", err)
					html = article.Content // Fallback to raw content
				}
				articleItems = append(articleItems, generator.ArticleItemInfo{
					DTag:      article.DTag,
					Title:     article.Title,
					Summary:   article.Summary,
					Content:   template.HTML(html),
					Author:    event.PubKey,
					Image:     article.Image,
					CreatedAt: int64(event.CreatedAt),
				})
			}
			logger.WithField("items", len(articleItems)).Debug("Generated article items")

			// Store all article items for landing page
			allArticleItems = articleItems

			// Get newest article item for landing page
			if len(articleItems) > 0 {
				newestArticleItem = &articleItems[0]
			}

			// Generate articles page
			articlesHTML, err := r.htmlGenerator.GenerateArticlesPage(articleItems, []generator.FeedItemInfo{})
			if err != nil {
				logger.Errorf("Error generating articles page: %v", err)
			} else {
				if err := r.cache.Set("/articles", articlesHTML); err != nil {
					logger.Errorf("Error caching articles page: %v", err)
				} else {
					logger.WithField("items", len(articleItems)).Info("Articles page cached successfully")
				}
			}
		}
	}

	// Fetch and cache e-books page (needed for landing page)
	// If theforest fails, leave pages as-is (don't remove existing events)
	var allEBooks []generator.EBookInfo
	if r.ebooksService != nil {
		ebooks, err := r.ebooksService.FetchTopLevelIndexEvents(ctx)
		if err != nil {
			logger.Warnf("Error fetching e-books from theforest: %v - keeping existing pages", err)
			// Don't update cache - leave existing pages as-is
		} else {
			// Convert to generator.EBookInfo
			generatorEBooks := make([]generator.EBookInfo, 0, len(ebooks))
			for _, ebook := range ebooks {
				generatorEBooks = append(generatorEBooks, generator.EBookInfo{
					EventID:   ebook.EventID,
					Title:     ebook.Title,
					DTag:      ebook.DTag,
					Author:    ebook.Author,
					Summary:   ebook.Summary,
					Image:     ebook.Image,
					Type:      ebook.Type,
					CreatedAt: ebook.CreatedAt,
					Naddr:     ebook.Naddr,
				})
			}

			// Store all e-books for landing page
			allEBooks = generatorEBooks

			ebooksHTML, err := r.htmlGenerator.GenerateEBooksPage(generatorEBooks, []generator.FeedItemInfo{})
			if err != nil {
				logger.Errorf("Error generating e-books page: %v", err)
			} else {
				if err := r.cache.Set("/ebooks", ebooksHTML); err != nil {
					logger.Errorf("Error caching e-books page: %v", err)
				} else {
					logger.WithField("ebooks", len(generatorEBooks)).Info("E-books page cached successfully")
				}
			}
		}
	}

	// Always generate landing page AFTER blog, articles, and e-books are fetched and cached
	// Now we have all the data needed for the landing page
	landingHTML, err := r.htmlGenerator.GenerateLandingPage(wikiPages, newestBlogItem, newestArticleItem, allArticleItems, allEBooks)
	if err != nil {
		logger.Errorf("Error generating landing page: %v", err)
	} else {
		if err := r.cache.Set("/", landingHTML); err != nil {
			logger.Errorf("Error caching landing page: %v", err)
		} else {
			logger.WithField("pages", len(wikiPages)).Info("Landing page cached successfully")
		}
	}

	// Generate and cache Feed page (using feed items from cache)
	feedItems := r.convertFeedItemsToInfo(r.feedCache.Get())
	feedHTML, err := r.htmlGenerator.GenerateFeedPage(feedItems)
	if err != nil {
		logger.Errorf("Error generating feed page: %v", err)
	} else {
		if err := r.cache.Set("/feed", feedHTML); err != nil {
			logger.Errorf("Error caching feed page: %v", err)
		} else {
			logger.WithField("items", len(feedItems)).Info("Feed page cached successfully")
		}
	}

	logger.Info("Page cache rewarming completed")
}

// rewarmFeed rewarms the feed cache
func (r *Rewarmer) rewarmFeed(ctx context.Context) {
	logger.WithFields(map[string]interface{}{
		"relay":      r.feedRelay,
		"max_events": r.maxFeedEvents,
	}).Info("Starting feed cache rewarming")

	nostrItems, err := r.feedService.FetchFeedItems(ctx, r.feedRelay, r.maxFeedEvents)
	if err != nil {
		logger.WithField("relay", r.feedRelay).Warnf("Error fetching feed: %v", err)
		// Don't clear the cache on error - keep old items
		return
	}

	if len(nostrItems) == 0 {
		logger.WithField("relay", r.feedRelay).Warn("No feed items fetched")
		// Don't clear the cache - keep old items
		return
	}

	// Convert nostr.FeedItem to cache.FeedItem
	items := make([]FeedItem, 0, len(nostrItems))
	for _, item := range nostrItems {
		items = append(items, FeedItem{
			EventID: item.EventID,
			Author:  item.Author,
			Content: item.Content,
			Time:    item.Time,
			Link:    item.Link,
			Title:   item.Title,
			Summary: item.Summary,
			Image:   item.Image,
		})
	}

	r.feedCache.Set(items)
	logger.WithFields(map[string]interface{}{
		"items": len(items),
		"relay": r.feedRelay,
	}).Info("Feed cache rewarmed successfully")
}

// periodicRewarmPages periodically rewarms pages
func (r *Rewarmer) periodicRewarmPages(ctx context.Context) {
	ticker := time.NewTicker(r.interval)
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-ticker.C:
			r.rewarmPages(ctx)
		}
	}
}

// convertFeedItemsToInfo converts cache.FeedItem to generator.FeedItemInfo
func (r *Rewarmer) convertFeedItemsToInfo(items []FeedItem) []generator.FeedItemInfo {
	feedItems := make([]generator.FeedItemInfo, 0, len(items))
	for _, item := range items {
		feedItems = append(feedItems, generator.FeedItemInfo{
			EventID: item.EventID,
			Author:  item.Author,
			Content: item.Content,
			Time:    item.Time.Format("2006-01-02 15:04:05"),
			TimeISO: item.Time.Format(time.RFC3339),
			Link:    item.Link,
		})
	}
	return feedItems
}

// periodicRewarmFeed periodically rewarms feed
func (r *Rewarmer) periodicRewarmFeed(ctx context.Context) {
	ticker := time.NewTicker(r.feedInterval)
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-ticker.C:
			r.rewarmFeed(ctx)
		}
	}
}