package docs

import (
	"bytes"
	"fmt"
	"net/http"
	"strings"

	"bookhoard/internal/database"
	"bookhoard/templates"

	"github.com/google/uuid"
	"github.com/labstack/echo/v5"
)

// HTTPHandler wraps the docs handler for Echo framework
type HTTPHandler struct {
	docs *DocsHandler
}

// NewHTTPHandler creates a new docs HTTP handler
func NewHTTPHandler(docsPath string) *HTTPHandler {
	return &HTTPHandler{
		docs: NewDocsHandler(docsPath),
	}
}

// currentUser builds the template user from the optional auth middleware.
// Docs routes render for both anonymous and signed-in visitors, so an empty
// context user is a normal, expected state here.
func (h *HTTPHandler) currentUser(c *echo.Context) templates.User {
	if userID := c.Get("user"); userID != nil {
		dbUser := userID.(database.Users)
		theme := "tokyo-night"
		if dbUser.Theme.Valid {
			theme = dbUser.Theme.String
		}
		return templates.User{
			ID:       uuid.UUID(dbUser.ID.Bytes).String(),
			Username: dbUser.Username,
			Email:    dbUser.Email,
			Role:     dbUser.Role,
			Theme:    theme,
		}
	}
	return templates.User{Theme: "tokyo-night"}
}

// renderDocPage renders a document inside the docs layout.
func (h *HTTPHandler) renderDocPage(c *echo.Context, doc *templates.Document) error {
	currentPath := c.Request().URL.Path
	nav := h.docs.BuildNavigation(currentPath)

	var buf bytes.Buffer
	if err := templates.DocsLayout(*nav, *doc, h.currentUser(c), currentPath).Render(c.Request().Context(), &buf); err != nil {
		fmt.Printf("DOCS RENDER ERROR: %v\n", err)
		return c.HTML(http.StatusInternalServerError, "Failed to render page: "+err.Error())
	}
	return c.HTML(http.StatusOK, buf.String())
}

// notFoundPage renders the standalone 404 page (no app chrome, no CDN).
func (h *HTTPHandler) notFoundPage(c *echo.Context, title, message string) error {
	var buf bytes.Buffer
	if err := templates.DocsNotFound(title, message).Render(c.Request().Context(), &buf); err != nil {
		return c.HTML(http.StatusInternalServerError, "Failed to render page")
	}
	return c.HTML(http.StatusNotFound, buf.String())
}

// ShowDocumentation renders a documentation page
func (h *HTTPHandler) ShowDocumentation(c *echo.Context) error {
	// Get the document path from URL parameter
	docPath := c.Param("*")

	// Load the document
	doc, err := h.docs.LoadDocument(docPath)
	if err != nil {
		// Try to load as API endpoint
		if strings.HasPrefix(docPath, "api/") {
			return h.ShowAPIEndpoint(c, strings.TrimPrefix(docPath, "api/"))
		}

		return h.notFoundPage(c, "Document Not Found", err.Error())
	}

	return h.renderDocPage(c, doc)
}

// DocsHome renders the documentation index at /docs.
func (h *HTTPHandler) DocsHome(c *echo.Context) error {
	doc, err := h.docs.LoadDocument("index.md")
	if err != nil {
		return h.notFoundPage(c, "Documentation Not Found", err.Error())
	}
	return h.renderDocPage(c, doc)
}

// ShowAPIEndpoint shows a specific API endpoint documentation
func (h *HTTPHandler) ShowAPIEndpoint(c *echo.Context, endpointPath string) error {
	// Load the markdown documentation for this endpoint
	docPath := "api/" + endpointPath + ".md"
	doc, err := h.docs.LoadDocument(docPath)
	if err != nil {
		return h.notFoundPage(c, "API Endpoint Not Found", "No documentation exists for this endpoint.")
	}

	return h.renderDocPage(c, doc)
}

// searchDocs runs the docs search and returns ranked, capped results.
// Title matches outrank content matches.
func (h *HTTPHandler) searchDocs(query string) []templates.SearchResultItem {
	queryLower := strings.ToLower(strings.TrimSpace(query))
	if queryLower == "" {
		return nil
	}

	docs, err := h.docs.ListDocuments()
	if err != nil {
		return nil
	}

	var titleMatches, contentMatches []templates.SearchResultItem
	for _, docPath := range docs {
		doc, err := h.docs.LoadDocument(docPath)
		if err != nil {
			continue
		}

		item := templates.SearchResultItem{
			Title:    doc.Title,
			Category: doc.Category,
			URL:      "/docs/" + strings.TrimSuffix(doc.SourceFile, ".md"),
		}
		if doc.SourceFile == "index.md" {
			item.URL = "/docs"
		}

		if strings.Contains(strings.ToLower(doc.Title), queryLower) {
			titleMatches = append(titleMatches, item)
			continue
		}
		if strings.Contains(strings.ToLower(doc.Content), queryLower) {
			contentMatches = append(contentMatches, item)
		}
	}

	results := append(titleMatches, contentMatches...)
	const maxResults = 30
	if len(results) > maxResults {
		results = results[:maxResults]
	}
	return results
}

// SearchPartial renders the search results HTML partial for the docs header
// search box. The client swaps this markup in verbatim (rendering ownership:
// the server renders the results, TypeScript only moves them).
func (h *HTTPHandler) SearchPartial(c *echo.Context) error {
	results := h.searchDocs(c.QueryParam("q"))

	var buf bytes.Buffer
	if err := templates.DocsSearchResults(results).Render(c.Request().Context(), &buf); err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{
			"error": "failed to render search results",
		})
	}
	c.Response().Header().Set("Content-Type", "text/html; charset=UTF-8")
	return c.HTML(http.StatusOK, buf.String())
}

// Search searches through documentation (JSON API).
func (h *HTTPHandler) Search(c *echo.Context) error {
	query := c.QueryParam("q")
	if query == "" {
		return c.JSON(http.StatusBadRequest, map[string]string{
			"error": "query parameter 'q' is required",
		})
	}

	results := h.searchDocs(query)
	jsonResults := make([]SearchResult, 0, len(results))
	for _, r := range results {
		jsonResults = append(jsonResults, SearchResult{
			Title: r.Title,
			URL:   r.URL,
			Type:  r.Category,
		})
	}

	return c.JSON(http.StatusOK, map[string]interface{}{
		"results": jsonResults,
		"count":   len(jsonResults),
	})
}

// SearchResult represents a search result
type SearchResult struct {
	Title string
	URL   string
	Type  string
}

// ServeSearchIndex serves the Lunr.js search index
func (h *HTTPHandler) ServeSearchIndex(c *echo.Context) error {
	index, err := h.docs.GenerateSearchIndex()
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{
			"error": "failed to generate search index",
		})
	}
	return c.JSON(http.StatusOK, index)
}