package main

import(
    "math"
    "html/template"
    "net/url"
    "strconv"
    "log"
)

var funcMap = template.FuncMap{
        "min": math.Min,
        "genRoute": func (name string, params ...string) string { 
        	url, err := router.Get(name).URL(params...)
        	if (err == nil) {
        		return url.String()
        	}
        	return "error"
        	},
        "genNav" : func (nav Navigation, currentUrl *url.URL, pagesSelectable int) template.HTML {
            maxPages := math.Ceil(float64(nav.TotalItem)/float64(nav.MaxItemPerPage))
            route := router.Get(nav.Route)

        	var ret = ""
            if nav.CurrentPage-1 > 0 {
                url, _ := route.URL("page", "1")
                ret = ret + "<li><a id=\"page-prev\" href=\""+ url.String() + "?" + currentUrl.RawQuery +"\" aria-label=\"Previous\"><span aria-hidden=\"true\">&laquo;</span></a></li>"
            }
            startValue := 1
            if (nav.CurrentPage > pagesSelectable) {
              startValue = (int(math.Min((float64(nav.CurrentPage) + math.Floor(float64(pagesSelectable)/2)), maxPages))-pagesSelectable+1)
            } 
            endValue := (startValue+pagesSelectable-1)
            if (endValue > int(maxPages)) { endValue = int(maxPages) }
            log.Println(nav.TotalItem)
            for i := startValue; i <= endValue; i++ {
                pageNum := strconv.Itoa(i)
                url,_ := route.URL("page", pageNum)
                ret = ret + "<li" 
                if (i == nav.CurrentPage) { ret = ret + " class=\"active\"" }

                ret = ret + "><a href=\""+ url.String() + "?" + currentUrl.RawQuery +"\">"+strconv.Itoa(i)+"</a></li>"
            }
            if nav.CurrentPage < int(maxPages) {
                url, _ := route.URL("page", strconv.Itoa(nav.CurrentPage+1))
                ret = ret + "<li><a id=\"page-next\" href=\""+ url.String() + "?" + currentUrl.RawQuery +"\" aria-label=\"Next\"><span aria-hidden=\"true\">&raquo;</span></a></li>"
            }
            return template.HTML(ret)
        	},
    }