package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"text/template"
	"time"
)

var SharedCache *Datastore

type Link struct {
	Url           string `json:"url"`
	PublishedDate string `json:"publishedDate"`
	Title         string `json:"title"`
}

// Healthcheck route
//
// Confirms that the app is alive without guarantees
// about it being fully-functional.
func healthcheck(w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(200)
}

// About page
//
// Static content for the about page.
func about(w http.ResponseWriter, r *http.Request) {
	tmpl, _ := template.New("about.html.tmpl").ParseFiles("templates/about.html.tmpl")
	tmpl.Execute(w, nil)
}

// Feeds list
//
// Lists all feed elements in store.
func listContent(w http.ResponseWriter, r *http.Request) {
	links := []Link{}
	for _, feed := range SharedCache.List("feeds") {
		var formattedItems []Link
		json.Unmarshal([]byte(feed), &formattedItems)
		links = append(links, formattedItems...)
	}

	tmpl, _ := template.New("index.html.tmpl").ParseFiles("templates/index.html.tmpl")
	tmpl.Execute(w, links)
}

// Manage content
//
// Interface to add new feed subscriptions and get a list
// of current subs.
func manageContent(w http.ResponseWriter, r *http.Request) {
	if r.Method == "POST" {
		r.ParseForm()

		urlValue := r.PostFormValue("url")

		if _, err := url.Parse(urlValue); err != nil {
			w.WriteHeader(400)
			return
		}

		cacheKey := fmt.Sprintf("feedurl:%s", urlValue)
		SharedCache.Set(cacheKey, urlValue)

		go fetchFeed(urlValue)

		w.WriteHeader(201)
	}

	allFeeds := SharedCache.List("feedurl")

	type ManageTmplData struct {
		Feeds map[string]string
	}

	tmpl, _ := template.New("manage.html.tmpl").ParseFiles("templates/manage.html.tmpl")
	tmpl.Execute(w, ManageTmplData{Feeds: allFeeds})
}

var routeMap = map[string]http.HandlerFunc{
	"/":       listContent,
	"/about":  about,
	"/manage": manageContent,
	"/ping":   healthcheck,
}

func main() {
	SharedCache = &Datastore{
		Data: map[string]string{},
	}

	if existingStore := FromFile("datastore.json"); existingStore != nil {
		SharedCache = existingStore
	}

	api := API{StaticRoot: "./static"}

	for route, handler := range routeMap {
		api.AddRoute(route, handler)
	}

	go func() {
		for {
			refreshFeeds()
			time.Sleep(10 * time.Minute)
		}
	}()

	api.Start(":9000")
}