package main

import (
	"html/template"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
)

const DATA_DIR = "files"
const DATA_URI = "/files"

type File struct {
	Filename string
	URL      string
}

type Template struct {
	templates *template.Template
}

func (t *Template) Render(w io.Writer, name string, data interface{}, c echo.Context) error {
	return t.templates.ExecuteTemplate(w, name, data)
}

func upload(c echo.Context) error {
	// Source
	file, err := c.FormFile("file")
	if err != nil {
		return err
	}
	src, err := file.Open()
	if err != nil {
		return err
	}
	defer src.Close()

	// Destination
	destinationPath := filepath.Join(DATA_DIR, file.Filename)
	destinationUrl := filepath.Join(DATA_URI, file.Filename)
	dst, err := os.Create(destinationPath)
	if err != nil {
		return err
	}
	defer dst.Close()

	// Copy
	if _, err = io.Copy(dst, src); err != nil {
		return err
	}

	return c.Render(http.StatusOK, "uploaded", map[string]string{"URI": destinationUrl})
}

func listFiles() ([]File, error) {
	files := make([]File, 0)

	dirEntries, err := os.ReadDir(DATA_DIR)
	if err != nil {
		return files, err
	}

	for _, dirEntry := range dirEntries {
		if dirEntry.IsDir() {
			continue
		}

		if strings.HasPrefix(dirEntry.Name(), ".") {
			continue
		}

		files = append(files, File{
			Filename: dirEntry.Name(),
			URL:      filepath.Join(DATA_URI, dirEntry.Name()),
		})
	}

	return files, nil
}

func index(c echo.Context) error {
	files, err := listFiles()
	if err != nil {
		return err
	}
	return c.Render(http.StatusOK, "index", map[string][]File{"Files": files})
}

func remove(c echo.Context) error {
	filename := c.FormValue("Filename")
	os.Remove(filepath.Join(DATA_DIR, filename))
	return c.Redirect(http.StatusTemporaryRedirect, "/admin")
}

func main() {
	t := &Template{
		templates: template.Must(template.ParseGlob("views/templates/*.html")),
	}

	e := echo.New()

	e.Renderer = t
	e.Use(middleware.Logger())
	e.Use(middleware.Recover())

	e.Static(DATA_URI, DATA_DIR)
	e.Static("/assets", "assets")
	e.GET("/admin", index)
	e.POST("/admin/upload", upload)
	e.GET("/admin/remove", remove)

	e.Logger.Fatal(e.Start(":1323"))
}