package main

import (
	"errors"
	"fmt"
	"github.com/dballard/transmet/categories"
	"github.com/gorilla/csrf"
	"html/template"
	"net/http"
	"path/filepath"
	"regexp"
	"strings"
	"time"
)

var (
	templates = map[string]*template.Template{}
)

// template helper function
func dict(values ...interface{}) (map[string]interface{}, error) {
	if len(values)%2 != 0 {
		return nil, errors.New("invalid dict call")
	}
	dict := make(map[string]interface{}, len(values)/2)
	for i := 0; i < len(values); i += 2 {
		key, ok := values[i].(string)
		if !ok {
			return nil, errors.New("dict keys must be strings")
		}
		dict[key] = values[i+1]
	}
	return dict, nil
}

// string multiplication
// stringTimes(3, "Foo") => "FooFooFoo"
func stringTimes(times int, str string) string {
	result := ""
	for i := 0; i < times; i++ {
		result += str
	}
	return result
}

// Turns a Time into a formated string
func dateFormat(t time.Time) string {
	return t.Format("2006.01.02 15:04:05")
}

// takes a category_id and returns "Root / Parent / Category"
func fullCategoryPath(categoriesFlat map[int]*categories.Category, category_id int) string {
	var categoryNames []string = nil
	for category := categoriesFlat[category_id]; category != nil; category = categoriesFlat[int(category.Parent.Int64)] {
		categoryNames = append([]string{category.Name}, categoryNames...)
	}
	return strings.Join(categoryNames, " / ")
}

// truncate a string
func truncate(str string, maxLen int) string {
	if len(str) <= maxLen {
		return str
	}
	return str[0:maxLen] + "..."
}

// Tempalte helper functions
var funcMap = template.FuncMap{
	"add":              func(x, y int) int { return x + y },
	"minus":            func(x, y int) int { return x - y },
	"dict":             dict,
	"stringTimes":      stringTimes,
	"dateFormat":       dateFormat,
	"fullCategoryPath": fullCategoryPath,
	"truncate":         truncate,
}

func initTemplates() {
	files, _ := filepath.Glob("templates/pages/*.html")
	re := regexp.MustCompile("templates/pages/(.*).html")
	fmt.Println("Loading Templates:")
	for _, t := range files {
		name := re.FindStringSubmatch(t)
		fmt.Println("  ", name[1])
		templates[name[1]] = template.Must(template.New(name[1]).Funcs(funcMap).ParseFiles("templates/layout.html", t))
	}
}

func ShowTemplate(template string, w http.ResponseWriter, r *http.Request, data map[string]interface{}) {
	data[csrf.TemplateTag] = csrf.TemplateField(r)
	err := templates[template].ExecuteTemplate(w, "layout.html", data)
	if err != nil {
		fmt.Println("Exec err: ", err)
	}
	// TODO: show error 500 page
}