package notify

import (
	"context"
	"fmt"
	"testing"
	"text/template"

	ntf "github.com/go-pkgz/notify"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/umputun/remark42/backend/app/store"
)

func TestEmailNew(t *testing.T) {
	emailParams := EmailParams{
		From:                     "test@from",
		VerificationTemplatePath: "testdata/verification.html.tmpl",
		MsgTemplatePath:          "testdata/msg.html.tmpl",
	}
	smtpParams := ntf.SMTPParams{
		Host:     "test@host",
		Port:     1000,
		TLS:      true,
		StartTLS: true,
		Username: "test@username",
		Password: "test@password",
	}

	email, err := NewEmail(emailParams, smtpParams)

	assert.NoError(t, err)
	assert.NotNil(t, email, "email returned")

	assert.NotNil(t, email.msgTmpl, "e.template is set")
	assert.Equal(t, emailParams.From, email.EmailParams.From, "emailParams.From unchanged after creation")
	if smtpParams.TimeOut == 0 {
		assert.Equal(t, defaultEmailTimeout, email.TimeOut, "empty emailParams.TimeOut changed to default")
	} else {
		assert.Equal(t, smtpParams.TimeOut, email.TimeOut, "emailParams.TimOut unchanged after creation")
	}
	assert.Equal(t, smtpParams.Host, email.Host, "emailParams.Host unchanged after creation")
	assert.Equal(t, smtpParams.Username, email.Username, "emailParams.Username unchanged after creation")
	assert.Equal(t, smtpParams.Password, email.Password, "emailParams.Password unchanged after creation")
	assert.Equal(t, smtpParams.Port, email.Port, "emailParams.Port unchanged after creation")
	assert.Equal(t, smtpParams.TLS, email.TLS, "emailParams.TLS unchanged after creation")
	assert.Equal(t, smtpParams.StartTLS, email.StartTLS, "emailParams.TLS unchanged after creation")
	assert.Equal(t, "email: with username 'test@username' at server test@host:1000 with TLS with StartTLS", email.String())
}

func Test_initTemplatesErr(t *testing.T) {
	testSet := []struct {
		name        string
		errText     string
		emailParams EmailParams
	}{
		{
			name:    "with wrong path to verification template",
			errText: "notfound.tmpl: file does not exist",
			emailParams: EmailParams{
				VerificationTemplatePath: "notfound.tmpl",
			},
		},
		{
			name:    "with wrong path to message template",
			errText: "notfound.tmpl: file does not exist",
			emailParams: EmailParams{
				MsgTemplatePath: "notfound.tmpl",
			},
		},
		{
			name:    "with error on read verification template",
			errText: "can't parse verification template: template: verifyTmpl",
			emailParams: EmailParams{
				VerificationTemplatePath: "testdata/bad.html.tmpl",
				MsgTemplatePath:          "testdata/msg.html.tmpl",
			},
		},
		{
			name:    "with error on read message template",
			errText: "can't parse message template: template: msgTmpl",
			emailParams: EmailParams{
				VerificationTemplatePath: "testdata/verification.html.tmpl",
				MsgTemplatePath:          "testdata/bad.html.tmpl",
			},
		},
	}

	for _, d := range testSet {
		d := d
		t.Run(d.name, func(t *testing.T) {
			e, err := NewEmail(d.emailParams, ntf.SMTPParams{})
			require.Error(t, err)
			require.Nil(t, e)
			assert.Contains(t, err.Error(), d.errText)
		})
	}
}

func TestEmailSendErrors(t *testing.T) {
	var err error
	e := Email{}
	e.TokenGenFn = TokenGenFn

	e.verifyTmpl, err = template.New("test").Parse("{{.Test}}")
	assert.NoError(t, err)
	assert.EqualError(t, e.SendVerification(context.Background(), VerificationRequest{Email: "bad@example.org", Token: "some"}),
		"error executing template to build verification message: template: test:1:2: executing \"test\" at <.Test>: can't evaluate field Test in type notify.verifyTmplData")

	e.msgTmpl, err = template.New("test").Parse("{{.Test}}")
	assert.NoError(t, err)
	assert.EqualError(t, e.Send(context.Background(), Request{Comment: store.Comment{ID: "999"}, parent: store.Comment{User: store.User{ID: "test"}}, Emails: []string{"bad@example.org"}}),
		"1 error occurred:\n\t* problem sending user email notification to \"bad@example.org\": "+
			"error executing template to build comment reply message: "+
			"template: test:1:2: executing \"test\" at <.Test>: "+
			"can't evaluate field Test in type notify.msgTmplData\n\n")

	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	assert.EqualError(t, e.Send(ctx, Request{Comment: store.Comment{ID: "999"}, parent: store.Comment{User: store.User{ID: "test"}}, Emails: []string{"bad@example.org"}}),
		"sending email messages about comment \"999\" aborted due to canceled context")

	assert.EqualError(t, e.Send(context.Background(), Request{Comment: store.Comment{ID: "999"}, parent: store.Comment{User: store.User{ID: "error"}}, Emails: []string{"bad@example.org"}}),
		"1 error occurred:\n\t* problem sending user email notification to \"bad@example.org\":"+
			" error creating token for unsubscribe link: token generation error\n\n")
}

func TestEmailSend_ExitConditions(t *testing.T) {
	email, err := NewEmail(EmailParams{
		VerificationTemplatePath: "testdata/verification.html.tmpl",
		MsgTemplatePath:          "testdata/msg.html.tmpl",
	}, ntf.SMTPParams{})
	assert.NoError(t, err)
	assert.NotNil(t, email, "expecting email returned")
	// prevent triggering e.autoFlush creation
	emptyRequest := Request{Comment: store.Comment{ID: "999"}}
	assert.NoError(t, email.Send(context.Background(), emptyRequest),
		"Message without Emails and AdminEmails is not sent and returns nil")
}

func TestEmail_Send(t *testing.T) {
	email, err := NewEmail(EmailParams{
		From:                     "from@example.org",
		VerificationTemplatePath: "testdata/verification.html.tmpl",
		MsgTemplatePath:          "testdata/msg.html.tmpl",
	}, ntf.SMTPParams{})
	assert.NoError(t, err)
	assert.NotNil(t, email)
	email.TokenGenFn = TokenGenFn
	email.UnsubscribeURL = "https://remark42.com/api/v1/email/unsubscribe"
	req := Request{
		Comment: store.Comment{ID: "999", User: store.User{ID: "1", Name: "test_user"}, ParentID: "1", PostTitle: "test_title"},
		parent:  store.Comment{ID: "1", User: store.User{ID: "999", Name: "parent_user"}},
		Emails:  []string{"test@example.org"},
	}
	assert.Contains(t, email.Send(context.Background(), req).Error(), "problem sending user email notification to \"test@example.org\"")
	// test buildMessageFromRequest separately for message text
	msg, err := email.buildMessageFromRequest(req, req.Emails[0], false)
	assert.NoError(t, err)
	assert.Equal(t, `
	New reply from test_user on your comment to «test_title»

User: test_user
01.01.0001 at 00:00
Comment: 
test@example.org  for parent_user
Unsubscribe link: https://remark42.com/api/v1/email/unsubscribe?site=&tkn=token
`, msg.body)
	assert.Equal(t, "https://remark42.com/api/v1/email/unsubscribe?site=&tkn=token", msg.unsubscribeLink)
	assert.Equal(t, `New reply to your comment for "test_title"`, msg.subject)

	// send email to both user and admin, without parent set
	email.AdminEmails = []string{"admin@example.org"}
	req = Request{
		Comment: store.Comment{ID: "999", User: store.User{ID: "1", Name: "test_user"}, PostTitle: "test_title"},
		Emails:  []string{"test@example.org"},
	}
	assert.Error(t, email.Send(context.Background(), req))
	msg, err = email.buildMessageFromRequest(req, email.AdminEmails[0], true)
	assert.NoError(t, err)
	assert.Equal(t, `
New comment from test_user on your site  to «test_title»

User: test_user
01.01.0001 at 00:00
Comment: 
admin@example.org 
`, msg.body)
	assert.Equal(t, `New comment to your site for "test_title"`, msg.subject)
	assert.Empty(t, msg.unsubscribeLink)
}

func TestEmail_SendVerification(t *testing.T) {
	email, err := NewEmail(EmailParams{
		From:                     "from@example.org",
		VerificationTemplatePath: "testdata/verification.html.tmpl",
		MsgTemplatePath:          "testdata/msg.html.tmpl",
	}, ntf.SMTPParams{})
	assert.NoError(t, err)
	assert.NotNil(t, email)
	email.TokenGenFn = TokenGenFn
	// proper VerificationRequest without email
	req := VerificationRequest{
		SiteID: "remark",
		User:   "test_username",
		Token:  "secret_",
	}
	assert.NoError(t, email.SendVerification(context.Background(), req))

	// proper VerificationRequest with email
	req.Email = "test@example.org"
	assert.Error(t, email.SendVerification(context.Background(), req), "failed to make smtp client")

	// VerificationRequest with canceled context
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	assert.EqualError(t, email.SendVerification(ctx, req), "sending message to \"test_username\" aborted due to canceled context")

	// test buildVerificationMessage separately for message text
	res, err := email.buildVerificationMessage(req.User, req.Email, req.Token, req.SiteID)
	assert.NoError(t, err)
	assert.Equal(t, res, `Confirmation for test_username on site remark
Token:secret_
Sent to test@example.org

`)
	assert.Contains(t, res, `secret_`)
	assert.NotContains(t, res, `https://example.org/`)
	email.SubscribeURL = "https://example.org/subscribe.html?token="
	res, err = email.buildVerificationMessage(req.User, req.Email, req.Token, req.SiteID)
	assert.NoError(t, err)
	assert.Equal(t, res, `Confirmation for test_username on site remark
Subscribe url: https://example.org/subscribe.html?token=secret_
Token:secret_
Sent to test@example.org

`)
}

func TokenGenFn(user, _, _ string) (string, error) {
	if user == "error" {
		return "", fmt.Errorf("token generation error")
	}
	return "token", nil
}