package renderer

import (
	"errors"
	"fmt"
	"html/template"
	"net/url"
	"reflect"
	"strings"
	"time"

	"github.com/jinzhu/inflection"
	yml "gopkg.in/yaml.v2"
)

var (
	funcMap = template.FuncMap{
		"query":       query,
		"convertDate": convertDate,
		"modelPath":   modelPath,
		"dict":        dict,
		"yaml":        yaml,
		"create":      create,
		"show":        show,
	}
)

func yaml(content string) (interface{}, error) {
	var result interface{}
	err := yml.Unmarshal([]byte(content), &result)
	if err != nil {
		return nil, err
	}
	return result, nil
}

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
}

func slice(values ...string) []string {
	var result []string
	result = append(result, values...)
	return result
}

func getType(myvar interface{}) (res string) {
	t := reflect.TypeOf(myvar)
	for t.Kind() == reflect.Ptr {
		t = t.Elem()
		res += "*"
	}
	return res + t.Name()
}

func query(values ...string) template.URL {
	var urlValues url.Values

	urlValues = make(url.Values)
	urlValues.Set("format", "html")

	for i := 0; i < len(values); i += 2 {
		urlValues.Add(values[i], values[i+1])
	}
	return template.URL(urlValues.Encode())
}

func convertDate(t time.Time) string {
	return fmt.Sprintf("%d-%02d-%02d", t.Year(), t.Month(), t.Day())
}

func modelPath(model string, action string, id uint) string {
	var q template.URL

	action = strings.ToLower(action)
	plural := inflection.Plural(strings.ToLower(model))

	if action != "" {
		switch action {
		case "show":
			q = query("tpl_layout", "base", "tpl_content", fmt.Sprintf("%s_%s", plural, action))
			return fmt.Sprintf("/%s/%d?%s", plural, id, q)
		case "update":
			q = query("tpl_layout", "base", "tpl_content", fmt.Sprintf("%s_add_update", plural), "update", "true")
			return fmt.Sprintf("/%s/%d/%s?%s", plural, id, action, q)
		case "create":
			q = query("tpl_layout", "base", "tpl_content", fmt.Sprintf("%s_add_update", plural))
			return fmt.Sprintf("/%s/%s/?%s", plural, action, q)
		case "delete":
			q = query("tpl_layout", "base", "tpl_content", fmt.Sprintf("%s_%s", plural, action))
			return fmt.Sprintf("/%s/%d/%s?%s", plural, id, action, q)
		}
	}
	q = query("tpl_layout", "base", "tpl_content", plural)
	return fmt.Sprintf("/%s?%s", plural, q)
}

func create(model string) string {
	action := "create"
	plural := inflection.Plural(strings.ToLower(model))
	q := query("tpl_layout", "base", "tpl_content", fmt.Sprintf("%s_add_update", plural))

	return fmt.Sprintf("/%s/%s/?%s", plural, action, q)
}

func show(model string, id uint) string {
	action := "show"
	plural := inflection.Plural(strings.ToLower(model))
	q := query("tpl_layout", "base", "tpl_content", fmt.Sprintf("%s_%s", plural, action))

	return fmt.Sprintf("/%s/%d?%s", plural, id, q)
}