package servlet

import (
	"encoding/json"
	"errors"
	"fmt"
	"geniuscartel.xyz/vinegar/vinegarUtil"
	"io/ioutil"
)

type (
	ConfigType  string
	ConfigEntry struct {
		ConfigType      ConfigType
		UrlPattern      string
		FileLocation    string
		UseBuiltinCache bool
	}
	Config struct {
		ListeningAddress string
		Routes           []ConfigEntry
	}
)

const (
	Text       ConfigType = "Text"
	Image                 = "Image"
	SingleFile            = "SingleFile"
)

func CreateBlankConfig() *Config {
	conf := Config{
		ListeningAddress: ":8080",
		Routes:           make([]ConfigEntry, 0, 10),
	}

	dummyRoute := ConfigEntry{
		ConfigType:      Text,
		UrlPattern:      "/*",
		FileLocation:    "errors/",
		UseBuiltinCache: false,
	}

	conf.Routes = append(conf.Routes, dummyRoute)

	return &conf
}

func LoadConfig(pathlike string) *VinegarServlet {
	contents, exists := vinegarUtil.GetDiskContent(pathlike)
	if exists {
		conf := Config{}
		err := json.Unmarshal(*contents, &conf)
		if err != nil {
			panic(err)
			return nil
		}
		servlet := NewServlet(conf.ListeningAddress)
		for _, v := range conf.Routes {
			constructor, err := getConstructorFunction(v.ConfigType)
			if err != nil {
				panic(err)
				return nil
			}
			//we don't have to invoke servlet.AddRoute because the static routes already do that for us
			constructor(servlet, v.UrlPattern, v.FileLocation, v.UseBuiltinCache)

		}
		return servlet
	} else {
		CreateBlankConfig()
		panic("Could not find config file at" + pathlike)
		return nil
	}
}

func (e ConfigEntry) toRoute(serv *VinegarServlet) {
	constructor, err := getConstructorFunction(e.ConfigType)
	if err != nil {
		panic(err)
	}
	constructor(serv, e.UrlPattern, e.FileLocation, e.UseBuiltinCache)
}

func getConstructorFunction(t ConfigType) (RouteConstructor, error) {
	switch t {
	case Text:
		return NewTextRoute, nil
	case Image:
		return NewImageRoute, nil
	case SingleFile:
		return NewSingleFileRoute, nil
	}
	return nil, errors.New(fmt.Sprintf("could not determine constructor for invalid ConfigType: %s", t))
}

func GenerateBlankConfig() {
	fileName := "servlet.json.template.tmpl"
	conf := CreateBlankConfig()
	content, err := json.Marshal(&conf)
	if err != nil {
		panic(err)
	}
	fmt.Println("Generating a blank configuration file at ")
	ioutil.WriteFile(fileName, content, 0755)
}