package main

import (
    "io"
    "log"
    "mime/multipart"
    "net/http"
    "os"
    "path/filepath"
    "runtime"

    "github.com/cheggaaa/pb"
)

func main() {
    if len(os.Args) != 2 {
        log.Println("Usage: pipeUp <filename>\n")
        os.Exit(1)
    }

    input, err := os.Open(os.Args[1])
    check(err)
    defer input.Close()

    stat, err := input.Stat()
    check(err)

    pipeOut, pipeIn := io.Pipe()
    bar := pb.New(int(stat.Size())).SetUnits(pb.U_BYTES)
    bar.ShowSpeed = true

    writer := multipart.NewWriter(pipeIn)

    // do the request concurrently
    var resp *http.Response
    done := make(chan error)
    go func() {

        // prepare request
        req, err := http.NewRequest("POST", "http://localhost:9000/upload", pipeOut)
        if err != nil {
            done <- err
            return
        }

        req.Header.Set("Content-Type", writer.FormDataContentType())
        log.Println("Created Request")
        bar.Start()

        resp, err = http.DefaultClient.Do(req)
        if err != nil {
            done <- err
            return
        }


        done <- nil
    }()

    part, err := writer.CreateFormFile("file", filepath.Base(os.Args[1]))
    check(err)

    out := io.MultiWriter(part, bar)
    _, err = io.Copy(out, input)
    check(err)

    check(writer.Close())
    check(pipeIn.Close()) // need to close the pipe to

    check(<-done)

    bar.FinishPrint("Upload done!")

}

func check(err error) {
    _, file, line, _ := runtime.Caller(1)
    if err != nil {
        log.Fatalf("Fatal from <%s:%d>\nError:%s", file, line, err)
    }
}