package main

import (
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"os/exec"
	"testing"
	"time"
)

const tmpDir = "test_tmp_dir/"
const plainDir = tmpDir + "plain/"
const cipherDir = tmpDir + "cipher/"

func TestMain(m *testing.M) {

	fu := exec.Command("fusermount", "-u", plainDir)
	fu.Stdout = os.Stdout
	fu.Stderr = os.Stderr
	fu.Run()
	os.RemoveAll(tmpDir)

	err := os.MkdirAll(plainDir, 0777)
	if err != nil {
		panic("Could not create plainDir")
	}

	err = os.MkdirAll(cipherDir, 0777)
	if err != nil {
		panic("Could not create cipherDir")
	}

	c := exec.Command("./gocryptfs", cipherDir, plainDir)
	c.Stdout = os.Stdout
	c.Stderr = os.Stderr
	go c.Run()

	time.Sleep(3 * time.Second)

	r := m.Run()

	fu.Run()
	os.Exit(r)
}

func testWriteN(t *testing.T, fn string, n int, hashWant string) {
	file, err := os.Create(plainDir + fn)
	if err != nil {
		t.FailNow()
	}

	d := make([]byte, n)
	written, err := file.Write(d)
	if err != nil || written != len(d) {
		fmt.Printf("err=\"%s\", written=%d\n", err, written)
		t.Fail()
	}
	file.Close()

	buf, err := ioutil.ReadFile(plainDir + fn)
	if err != nil {
		t.Fail()
	}

	rawHash := md5.Sum(buf)
	hashActual := hex.EncodeToString(rawHash[:])
	if hashActual != hashWant {
		fmt.Printf("hashWant=%s hashActual=%s\n", hashWant, hashActual)
		t.Fail()
	}
}

func TestWrite10(t *testing.T) {
	testWriteN(t, "10", 10, "a63c90cc3684ad8b0a2176a6a8fe9005")
}

func TestWrite100(t *testing.T) {
	testWriteN(t, "100", 100, "6d0bb00954ceb7fbee436bb55a8397a9")
}

func TestWrite1M(t *testing.T) {
	testWriteN(t, "1M", 1024*1024, "b6d81b360a5672d80c27430f39153e2c")
}

func TestWrite1Mx100(t *testing.T) {
	testWriteN(t, "1Mx100", 1024*1024, "b6d81b360a5672d80c27430f39153e2c")
	// Read and check 100 times to catch race conditions
	var i int
	for i = 0; i < 100; i++ {
		buf, err := ioutil.ReadFile(plainDir + "1M")
		if err != nil {
			t.Fail()
		}
		rawHash := md5.Sum(buf)
		hashActual := hex.EncodeToString(rawHash[:])
		if hashActual != "b6d81b360a5672d80c27430f39153e2c" {
			fmt.Printf("Read corruption in loop # %d\n", i)
			t.FailNow()
		} else {
			//fmt.Print(".")
		}
	}
}

func BenchmarkStreamWrite(t *testing.B) {
	buf := make([]byte, 1024*1024)
	t.SetBytes(int64(len(buf)))

	file, err := os.Create(plainDir + "BenchmarkWrite")
	if err != nil {
		t.FailNow()
	}

	t.ResetTimer()
	var i int
	for i = 0; i < t.N; i++ {
		written, err := file.Write(buf)
		if err != nil {
			fmt.Printf("err=\"%s\", written=%d\n", err.Error(), written)
			t.FailNow()
		}
	}
}

func BenchmarkStreamRead(t *testing.B) {
	buf := make([]byte, 1024*1024)
	t.SetBytes(int64(len(buf)))
	file, err := os.Open(plainDir + "BenchmarkWrite")
	if err != nil {
		t.FailNow()
	}
	t.ResetTimer()
	var i int
	for i = 0; i < t.N; i++ {
		_, err := file.Read(buf)
		if err == io.EOF {
			fmt.Printf("Test file too small\n")
			t.SkipNow()
		} else if err != nil {
			fmt.Println(err)
			t.FailNow()
		}
	}
}