Poll-system/app/internal/utils/render.go

package utils

import (
	"bytes"
	"html/template"
	"net/http"
	"path/filepath"
)

// Helper functions for templates
var templateFuncs = template.FuncMap{
	"add": func(a, b int) int {
		return a + b
	},
	"sub": func(a, b int) int {
		return a - b
	},
	"eq": func(a, b interface{}) bool {
		return a == b
	},
	"pageRange": func(currentPage, totalPages int) []int {
		// Generate page numbers to show (max 7 pages)
		start := currentPage - 3
		end := currentPage + 3

		if start < 1 {
			end += 1 - start
			start = 1
		}
		if end > totalPages {
			start -= end - totalPages
			end = totalPages
		}
		if start < 1 {
			start = 1
		}

		var pages []int
		for i := start; i <= end; i++ {
			pages = append(pages, i)
		}
		return pages
	},
}

func Render(w http.ResponseWriter, tmpl string, data interface{}) {
	// Paths for layout + page templates
	layout := filepath.Join("/Users/mannpatel/Desktop/Poll-system/app/internal/templates/", "layout.html")
	page := filepath.Join("/Users/mannpatel/Desktop/Poll-system/app/internal/templates/", tmpl)

	// Parse files with helper functions
	tmpls, err := template.New("").Funcs(templateFuncs).ParseFiles(layout, page)
	if err != nil {
		http.Error(w, "Template parsing error: "+err.Error(), http.StatusInternalServerError)
		return
	}

	// Render to buffer first (catch errors before writing response)
	var buf bytes.Buffer
	err = tmpls.ExecuteTemplate(&buf, "layout", data)
	if err != nil {
		http.Error(w, "Template execution error: "+err.Error(), http.StatusInternalServerError)
		return
	}

	// Write final HTML to response
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	buf.WriteTo(w)
}