package handlers

import (
	"fmt"
	"log"
	"net/http"
	"path/filepath"
	"strings"
	"time"

	c "github.com/juanatsap/cv-site/internal/constants"
	"github.com/juanatsap/cv-site/internal/httputil"
	"github.com/juanatsap/cv-site/internal/middleware"
	"github.com/juanatsap/cv-site/internal/pdf"
)

// ==============================================================================
// PAGE HANDLERS
// These handlers render full HTML pages or page sections
// ==============================================================================

// Home renders the full CV page
func (h *CVHandler) Home(w http.ResponseWriter, r *http.Request) {
	// Check if this is a shortcut URL request (cv-jamr-{year}-{lang}.pdf)
	if strings.HasPrefix(r.URL.Path, "/cv-jamr-") && strings.HasSuffix(r.URL.Path, ".pdf") {
		h.DefaultCVShortcut(w, r)
		return
	}

	// Detect text-based browsers and serve plain text version
	if isTextBrowser(r) {
		h.PlainText(w, r)
		return
	}

	lang, ok := httputil.LangOrError(r)
	if !ok {
		HandleError(w, r, BadRequestError("Unsupported language. Use 'en' or 'es'"))
		return
	}

	// Prepare template data using shared helper
	data, err := h.prepareTemplateData(lang)
	if err != nil {
		HandleError(w, r, DataLoadError(err, "CV"))
		return
	}

	// Get user preferences from context (set by PreferencesMiddleware)
	prefs := middleware.GetPreferences(r)

	// Use preferences from context (already migrated by middleware)
	cvLength := prefs.CVLength
	cvIcons := prefs.CVIcons
	cvTheme := prefs.CVTheme

	// Add preference-specific fields to template data
	cvLengthClass := "cv-short"
	if cvLength == "long" {
		cvLengthClass = "cv-long"
	}
	data["CVLengthClass"] = cvLengthClass
	data["ShowIcons"] = (cvIcons == "show")
	data["ThemeClean"] = (cvTheme == "clean")

	// Render template
	tmpl, err := h.templates.Render("index.html")
	if err != nil {
		HandleError(w, r, TemplateError(err, "index.html"))
		return
	}

	w.Header().Set(c.HeaderContentType, c.ContentTypeHTML)
	if err := tmpl.Execute(w, data); err != nil {
		HandleError(w, r, TemplateError(err, "index.html"))
		return
	}
}

// CVContent renders just the CV content for HTMX swaps
func (h *CVHandler) CVContent(w http.ResponseWriter, r *http.Request) {
	lang, ok := httputil.LangOrError(r)
	if !ok {
		HandleError(w, r, BadRequestError("Unsupported language. Use 'en' or 'es'"))
		return
	}

	// Prepare template data using shared helper
	data, err := h.prepareTemplateData(lang)
	if err != nil {
		HandleError(w, r, DataLoadError(err, "CV"))
		return
	}

	// Render template
	tmpl, err := h.templates.Render("cv-content.html")
	if err != nil {
		HandleError(w, r, TemplateError(err, "cv-content.html"))
		return
	}

	w.Header().Set(c.HeaderContentType, c.ContentTypeHTML)
	if err := tmpl.Execute(w, data); err != nil {
		HandleError(w, r, TemplateError(err, "cv-content.html"))
		return
	}
}

// DefaultCVShortcut handles shortcut URLs for default CV downloads
// Pattern: /cv-jamr-{year}-{lang}.pdf (e.g., /cv-jamr-2025-en.pdf)
// Validates year matches current year and redirects to default PDF export
func (h *CVHandler) DefaultCVShortcut(w http.ResponseWriter, r *http.Request) {
	// Extract path (e.g., "/cv-jamr-2025-en.pdf")
	path := r.URL.Path
	log.Printf("DefaultCVShortcut called with path: %s", path)

	// Parse filename pattern: cv-jamr-{year}-{lang}.pdf
	parts := strings.Split(strings.TrimPrefix(path, "/"), "-")
	if len(parts) != 4 {
		http.NotFound(w, r)
		return
	}

	// Extract year and language
	yearStr := parts[2]
	langWithExt := parts[3] // "en.pdf" or "es.pdf"
	lang := strings.TrimSuffix(langWithExt, ".pdf")

	// Validate language
	if !c.SupportedLanguages[lang] {
		http.NotFound(w, r)
		return
	}

	// Validate year matches current year
	currentYear := fmt.Sprintf("%d", time.Now().Year())
	if yearStr != currentYear {
		// Return 404 if year doesn't match (old or future URLs)
		log.Printf("Invalid year in shortcut URL: %s (current: %s)", yearStr, currentYear)
		http.NotFound(w, r)
		return
	}

	// Generate PDF directly instead of redirecting
	// This ensures the Content-Disposition filename is respected by browsers
	log.Printf("Shortcut URL: %s → generating PDF (short + with_skills)", path)

	// Prepare cookies for PDF generation (short, with_skills, light mode)
	cookies := map[string]string{
		c.CookieCVLength:   c.CVLengthShort,
		c.CookieCVIcons:    c.CVIconsShow,
		c.CookieCVLanguage: lang,
		c.CookieCVTheme:    c.CVThemeDefault, // with_skills = default theme
		c.CookieColorTheme: c.ColorThemeLight, // Always light for PDFs
	}

	// Construct URL for PDF generation
	targetURL := fmt.Sprintf("http://%s/?lang=%s", h.serverAddr, lang)

	// Generate PDF with screen render mode (for sidebar layout)
	ctx := r.Context()
	pdfData, err := h.pdfGenerator.GenerateFromURLWithOptions(ctx, targetURL, cookies, pdf.RenderModeScreen)
	if err != nil {
		log.Printf("PDF generation failed for shortcut URL: %v", err)
		HandleError(w, r, InternalError(err))
		return
	}

	// Use the shortcut filename directly (simple, user-friendly)
	filename := filepath.Base(path) // cv-jamr-2025-en.pdf

	// Set response headers with shortcut filename
	w.Header().Set(c.HeaderContentType, c.ContentTypePDF)
	w.Header().Set(c.HeaderContentDisposition, fmt.Sprintf("attachment; filename=%s", filename))
	w.Header().Set(c.HeaderContentLength, fmt.Sprintf("%d", len(pdfData)))

	// Write PDF data
	if _, err := w.Write(pdfData); err != nil {
		log.Printf("Error writing PDF response: %v", err)
		return
	}

	log.Printf("PDF generated successfully: %s (%d bytes)", filename, len(pdfData))
}