package main

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"path/filepath"
	"time"

	"github.com/NYTimes/gziphandler"
	"golang.org/x/crypto/acme/autocert"
)

const AppName = `webscaffold`

type WebSession struct {
	LastRefreshTime time.Time
}

type Application struct {
	c       Config
	webfile http.Handler
	db      *sql.DB

	sessions map[string]WebSession
}

func (this *Application) Start() error {
	log.Printf("Starting %s application...", AppName)

	// Connect to DB
	err := this.connectToDB()
	if err != nil {
		return err
	}

	// Resources
	this.webfile = http.FileServer(http.Dir(this.c.WebrootDir))

	// Set up HTTP server
	if this.c.Autocert == "" {
		log.Printf("Starting web server (HTTP on %s)...", this.c.ListenAddress)
		return http.ListenAndServe(this.c.ListenAddress, this) // Plain HTTP

	} else {
		log.Printf("Starting web server (HTTPS as '%s' on :80 + :443)...", this.c.Autocert)
		return http.Serve(autocert.NewListener(this.c.Autocert), this) // HTTPS

	}
}

func (this *Application) respondWith(object interface{}, nerr netError) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) { // curry over extra arity
		if nerr != nil {
			nerr.Respond(w)
			return
		}

		// Plaintext response
		// Buffer the resulting json data, so that we can determine the final size

		jb, err := json.Marshal(object)
		if err != nil {
			systemError{err}.Respond(w)
			return
		}

		w.Header().Set(`Content-Type`, `application/json`)
		w.Header().Set(`Content-Length`, fmt.Sprintf("%d", len(jb)))
		w.WriteHeader(200)
		w.Write(jb)
	}
}

func (this *Application) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	r.Header.Set(`Server`, AppName+`/1.0`)

	switch r.Method {
	case "GET":
		r.Header.Set(`X-Frame-Options`, `Deny`)

		if r.URL.Path == `/` {
			http.ServeFile(w, r, filepath.Join(this.c.WebrootDir, "index.html")) // n.b. no gzip

		} else {
			gziphandler.GzipHandler(this.webfile).ServeHTTP(w, r)

		}

	case "POST":
		if r.URL.Path == `/api/v1/login` {
			resp, err := this.apiLogin(r)
			gziphandler.GzipHandler(this.respondWith(resp, err)).ServeHTTP(w, r)

		} else {
			http.Error(w, "not found", 404)

		}

	}
}