package templates

import (
	"fmt"
	"html/template"
	"io"
	"os"
	"path/filepath"
	"time"
)

type TemplateManager struct {
	templates map[string]*template.Template
}

func NewTemplateManager(templatesDir string) (*TemplateManager, error) {
	tm := &TemplateManager{
		templates: make(map[string]*template.Template),
	}

	// Define template functions
	funcMap := template.FuncMap{
		"formatDate": formatDate,
		"truncate":   truncate,
		"currency":   formatCurrency,
	}

	// Load all templates
	layouts, err := filepath.Glob(filepath.Join(templatesDir, "layouts/*.html"))
	if err != nil {
		return nil, err
	}

	partials, err := filepath.Glob(filepath.Join(templatesDir, "partials/*.html"))
	if err != nil {
		return nil, err
	}

	// Load page templates
	pages := []string{
		"customers/index.html",
		"customers/show.html",
		"customers/form.html",
		"customers/table.html",
		"products/index.html",
		"products/show.html",
		"products/form.html",
		"products/table.html",
		"purchase-orders/index.html",
		"purchase-orders/show.html",
		"purchase-orders/form.html",
		"purchase-orders/table.html",
		"enquiries/index.html",
		"enquiries/show.html",
		"enquiries/form.html",
		"enquiries/table.html",
		"emails/index.html",
		"emails/show.html",
		"emails/table.html",
		"emails/attachments.html",
		"documents/index.html",
		"documents/show.html",
		"documents/table.html",
		"documents/view.html",
		"documents/quote-view.html",
		"documents/invoice-view.html",
		"documents/purchase-order-view.html",
		"documents/orderack-view.html",
		"documents/packinglist-view.html",
		"index.html",
	}

	for _, page := range pages {
		pagePath := filepath.Join(templatesDir, page)
		files := append(layouts, partials...)
		files = append(files, pagePath)
		
		// For index pages, also include the corresponding table template
		if filepath.Base(page) == "index.html" {
			dir := filepath.Dir(page)
			tablePath := filepath.Join(templatesDir, dir, "table.html")
			// Check if table file exists before adding it
			if _, err := os.Stat(tablePath); err == nil {
				files = append(files, tablePath)
			}
		}
		
		// For documents view page, include all document type elements
		if page == "documents/view.html" {
			docElements := []string{
				"documents/quote-view.html",
				"documents/invoice-view.html",
				"documents/purchase-order-view.html",
				"documents/orderack-view.html",
				"documents/packinglist-view.html",
			}
			for _, elem := range docElements {
				elemPath := filepath.Join(templatesDir, elem)
				if _, err := os.Stat(elemPath); err == nil {
					files = append(files, elemPath)
				}
			}
		}
		
		tmpl, err := template.New(filepath.Base(page)).Funcs(funcMap).ParseFiles(files...)
		if err != nil {
			return nil, err
		}
		
		tm.templates[page] = tmpl
	}

	return tm, nil
}

func (tm *TemplateManager) Render(w io.Writer, name string, data interface{}) error {
	tmpl, ok := tm.templates[name]
	if !ok {
		return template.New("error").Execute(w, "Template not found")
	}
	
	return tmpl.ExecuteTemplate(w, "base", data)
}

func (tm *TemplateManager) RenderPartial(w io.Writer, templateFile, templateName string, data interface{}) error {
	tmpl, ok := tm.templates[templateFile]
	if !ok {
		return template.New("error").Execute(w, "Template not found")
	}
	
	return tmpl.ExecuteTemplate(w, templateName, data)
}

// Template helper functions
func formatDate(t interface{}) string {
	switch v := t.(type) {
	case time.Time:
		return v.Format("2006-01-02")
	case string:
		if tm, err := time.Parse("2006-01-02 15:04:05", v); err == nil {
			return tm.Format("2006-01-02")
		}
		return v
	default:
		return fmt.Sprintf("%v", v)
	}
}

func truncate(s string, n int) string {
	if len(s) <= n {
		return s
	}
	return s[:n] + "..."
}

func formatCurrency(amount float64) string {
	return fmt.Sprintf("$%.2f", amount)
}