package dkim

import (
	"bufio"
	"reflect"
	"strings"
	"testing"
)

var headerTests = []struct {
	h header
	s string
}{
	{
		h: header{"From: <mistuha@kiminonawa.moe>\r\n"},
		s: "From: <mistuha@kiminonawa.moe>\r\n\r\n",
	},
	{
		h: header{
			"From: <mistuha@kiminonawa.moe>\r\n",
			"Subject: Your Name\r\n",
		},
		s: "From: <mistuha@kiminonawa.moe>\r\n" +
			"Subject: Your Name\r\n" +
			"\r\n",
	},
}

func TestReadHeader(t *testing.T) {
	for _, test := range headerTests {
		r := strings.NewReader(test.s)
		h, err := readHeader(bufio.NewReader(r))
		if err != nil {
			t.Fatalf("Expected no error while reading error, got: %v", err)
		}

		if !reflect.DeepEqual(h, test.h) {
			t.Errorf("Expected header to be \n%v\n but got \n%v", test.h, h)
		}
	}
}

func TestReadHeader_incomplete(t *testing.T) {
	r := strings.NewReader("From: <mistuha@kiminonawa.moe>\r\nTo")
	_, err := readHeader(bufio.NewReader(r))
	if err == nil {
		t.Error("Expected an error while reading incomplete header")
	}
}

func TestFormatHeaderParams(t *testing.T) {
	params := map[string]string{
		"v": "1",
		"a": "rsa-sha256",
		"d": "example.org",
	}

	expected := "DKIM-Signature: a=rsa-sha256; d=example.org; v=1;"

	s := formatHeaderParams("DKIM-Signature", params)
	if s != expected {
		t.Errorf("Expected formatted params to be %q, but got %q", expected, s)
	}
}

func TestLongHeaderFolding(t *testing.T) {
	// see #29 and #27

	params := map[string]string{
		"v": "1",
		"a": "rsa-sha256",
		"d": "example.org",
		"h": "From:To:Subject:Date:Message-ID:Long-Header-Name",
	}

	expected := "DKIM-Signature: a=rsa-sha256; d=example.org;\r\n h=From:To:Subject:Date:Message-ID:Long-Header-Name; v=1;"

	s := formatHeaderParams("DKIM-Signature", params)
	if s != expected {
		t.Errorf("Expected formatted params to be\n\n %q\n\n, but got\n\n %q", expected, s)
	}
}

func TestSignedHeaderFolding(t *testing.T) {
	hValue := "From:To:Subject:Date:Message-ID:Long-Header-Name:Another-Long-Header-Name"

	params := map[string]string{
		"v": "1",
		"a": "rsa-sha256",
		"d": "example.org",
		"h": hValue,
	}

	s := formatHeaderParams("DKIM-Signature", params)
	if !strings.Contains(s, hValue) {
		t.Errorf("Signed Headers names (%v) are not well folded in the signed header %q", hValue, s)
	}
}

func TestParseHeaderParams_malformed(t *testing.T) {
	_, err := parseHeaderParams("abc; def")
	if err == nil {
		t.Error("Expected an error when parsing malformed header params")
	}
}

func TestHeaderPicker_Pick(t *testing.T) {
	t.Run("simple", func(t *testing.T) {
		predefinedHeaders := []string{"From", "to"}
		headers := header{
			"from: fst",
			"To: snd",
		}
		picker := newHeaderPicker(headers)
		for i, k := range predefinedHeaders {
			if headers[i] != picker.Pick(k) {
				t.Errorf("Parameter %s not found in headers %s", k, headers)
			}
		}
	})
	t.Run("a few same headers", func(t *testing.T) {
		predefinedHeaders := []string{"to", "to", "to"}
		// same headers must returns from Bottom to Top
		headers := header{
			"To: trd",
			"To: snd",
			"To: fst",
		}
		var lh = len(headers) - 1
		picker := newHeaderPicker(headers)
		for i, k := range predefinedHeaders {
			if headers[lh-i] != picker.Pick(k) {
				t.Errorf("Parameter %s not found in headers %s", k, headers)
			}
		}
	})
	t.Run("non-canonical header fields", func(t *testing.T) {
		headers := header{
			"Message-ID: asdf",
		}
		picker := newHeaderPicker(headers)
		if v := picker.Pick("Message-Id"); v != headers[0] {
			t.Errorf("Pick() = %q, want %q", v, headers[0])
		}
		if v := picker.Pick("Message-ID"); v != "" {
			t.Errorf("Pick() = %q, want %q", v, "")
		}
	})
}

func TestFoldHeaderField(t *testing.T) {
	// fake header with `len(header) % 75 == 74`. See #23
	header := `Minimum length header that generates the issue should be of 74 characters `
	expected := "Minimum length header that generates the issue should be of 74 characters \r\n"
	folded := foldHeaderField(header)
	if folded != expected {
		t.Errorf("Extra black line added in header:\n Actual:\n ---Start--- %v ---End---\nExpected: \n ---Start--- %v ---End---\n", folded, expected)
	}
}