package email

import (
	"testing"

	"bytes"
	"crypto/rand"
	"io"
	"io/ioutil"
	"mime"
	"mime/multipart"
	"net/mail"
	"net/smtp"
	"os"
)

func TestEmailTextHtmlAttachment(t *testing.T) {
	e := NewEmail()
	e.From = "Jordan Wright <test@example.com>"
	e.To = []string{"test@example.com"}
	e.Bcc = []string{"test_bcc@example.com"}
	e.Cc = []string{"test_cc@example.com"}
	e.Subject = "Awesome Subject"
	e.Text = "Text Body is, of course, supported!\n"
	e.HTML = "<h1>Fancy Html is supported, too!</h1>\n"
	e.Attach(bytes.NewBufferString("Rad attachement"), "rad.txt", "text/plain; charset=utf-8")

	raw, err := e.Bytes()
	if err != nil {
		t.Fatal("Failed to render message: ", e)
	}
	ioutil.WriteFile("golden", raw, os.ModePerm)

	msg, err := mail.ReadMessage(bytes.NewBuffer(raw))
	if err != nil {
		t.Fatal("Could not parse rendered message: ", err)
	}

	expectedHeaders := map[string]string{
		"To":      "test@example.com",
		"From":    "Jordan Wright <test@example.com>",
		"Cc":      "test_cc@example.com",
		"Subject": "Awesome Subject",
	}

	for header, expected := range expectedHeaders {
		if val := msg.Header.Get(header); val != expected {
			t.Errorf("Wrong value for message header %s: %v != %v", header, expected, val)
		}
	}

	// Were the right headers set?
	ct := msg.Header.Get("Content-type")
	mt, params, err := mime.ParseMediaType(ct)
	if err != nil {
		t.Fatal("Content-type header is invalid: ", ct)
	} else if mt != "multipart/mixed" {
		t.Fatalf("Content-type expected \"multipart/mixed\", not %v", mt)
	}
	b := params["boundary"]
	if b == "" {
		t.Fatalf("Invalid or missing boundary parameter: ", b)
	}
	if len(params) != 1 {
		t.Fatal("Unexpected content-type parameters")
	}

	// Is the generated message parsable?
	mixed := multipart.NewReader(msg.Body, params["boundary"])

	text, err := mixed.NextPart()
	if err != nil {
		t.Fatalf("Could not find text component of email: ", err)
	}

	// Does the text portion match what we expect?
	mt, params, err = mime.ParseMediaType(text.Header.Get("Content-type"))
	if err != nil {
		t.Fatal("Could not parse message's Content-Type")
	} else if mt != "multipart/alternative" {
		t.Fatal("Message missing multipart/alternative")
	}
	mpReader := multipart.NewReader(text, params["boundary"])
	part, err := mpReader.NextPart()
	if err != nil {
		t.Fatal("Could not read plain text component of message: ", err)
	}
	plainText, err := ioutil.ReadAll(part)
	if err != nil {
		t.Fatal("Could not read plain text component of message: ", err)
	}
	if !bytes.Equal(plainText, []byte("Text Body is, of course, supported!\r\n")) {
		t.Fatalf("Plain text is broken: %#q", plainText)
	}

	// Check attachments.
	_, err = mixed.NextPart()
	if err != nil {
		t.Fatalf("Could not find attachemnt compoenent of email: ", err)
	}

	if _, err = mixed.NextPart(); err != io.EOF {
		t.Error("Expected only text and one attachement!")
	}

}

func ExampleGmail() {
	e := NewEmail()
	e.From = "Jordan Wright <test@gmail.com>"
	e.To = []string{"test@example.com"}
	e.Bcc = []string{"test_bcc@example.com"}
	e.Cc = []string{"test_cc@example.com"}
	e.Subject = "Awesome Subject"
	e.Text = "Text Body is, of course, supported!"
	e.HTML = "<h1>Fancy Html is supported, too!</h1>"
	e.Send("smtp.gmail.com:587", smtp.PlainAuth("", e.From, "password123", "smtp.gmail.com"))
}

func ExampleAttach() {
	e := NewEmail()
	e.AttachFile("test.txt")
}

func Test_base64Wrap(t *testing.T) {
	file := "I'm a file long enough to force the function to wrap a\n" +
		"couple of lines, but I stop short of the end of one line and\n" +
		"have some padding dangling at the end."
	encoded := "SSdtIGEgZmlsZSBsb25nIGVub3VnaCB0byBmb3JjZSB0aGUgZnVuY3Rpb24gdG8gd3JhcCBhCmNv\r\n" +
		"dXBsZSBvZiBsaW5lcywgYnV0IEkgc3RvcCBzaG9ydCBvZiB0aGUgZW5kIG9mIG9uZSBsaW5lIGFu\r\n" +
		"ZApoYXZlIHNvbWUgcGFkZGluZyBkYW5nbGluZyBhdCB0aGUgZW5kLg==\r\n"

	var buf bytes.Buffer
	base64Wrap(&buf, []byte(file))
	if !bytes.Equal(buf.Bytes(), []byte(encoded)) {
		t.Fatalf("Encoded file does not match expected: %#q != %#q", string(buf.Bytes()), encoded)
	}
}

func Test_quotedPrintEncode(t *testing.T) {
	var buf bytes.Buffer
	text := "Dear reader!\n\n" +
		"This is a test email to try and capture some of the corner cases that exist within\n" +
		"the quoted-printable encoding.\n" +
		"There are some wacky parts like =, and this input assumes UNIX line breaks so\r\n" +
		"it can come out a little weird.  Also, we need to support unicode so here's a fish: 🐟\n"
	expected := "Dear reader!\r\n\r\n" +
		"This is a test email to try and capture some of the corner cases that exist=\r\n" +
		" within\r\n" +
		"the quoted-printable encoding.\r\n" +
		"There are some wacky parts like =3D, and this input assumes UNIX line break=\r\n" +
		"s so=0D\r\n" +
		"it can come out a little weird.  Also, we need to support unicode so here's=\r\n" +
		" a fish: =F0=9F=90=9F\r\n"

	if err := quotePrintEncode(&buf, text); err != nil {
		t.Fatal("quotePrintEncode: ", err)
	}

	if s := buf.String(); s != expected {
		t.Errorf("quotedPrintEncode generated incorrect results: %#q != %#q", s, expected)
	}
}

func Benchmark_quotedPrintEncode(b *testing.B) {
	text := "Dear reader!\n\n" +
		"This is a test email to try and capture some of the corner cases that exist within\n" +
		"the quoted-printable encoding.\n" +
		"There are some wacky parts like =, and this input assumes UNIX line breaks so\r\n" +
		"it can come out a little weird.  Also, we need to support unicode so here's a fish: 🐟\n"

	for i := 0; i <= b.N; i++ {
		if err := quotePrintEncode(ioutil.Discard, text); err != nil {
			panic(err)
		}
	}
}

func Benchmark_base64Wrap(b *testing.B) {
	// Reasonable base case; 128K random bytes
	file := make([]byte, 128*1024)
	if _, err := rand.Read(file); err != nil {
		panic(err)
	}
	for i := 0; i <= b.N; i++ {
		base64Wrap(ioutil.Discard, file)
	}
}