WIP

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/slack-go/slack v0.6.3
 	github.com/urfave/cli/v2 v2.1.1
 	gopkg.in/yaml.v2 v2.2.8
+	mvdan.cc/xurls/v2 v2.5.0
 )
 
 require (

go.sum

@@ -54,3 +54,5 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+mvdan.cc/xurls/v2 v2.5.0 h1:lyBNOm8Wo71UknhUs4QTFUNNMyxy2JEIaKKo0RWOh+8=
+mvdan.cc/xurls/v2 v2.5.0/go.mod h1:yQgaGQ1rFtJUzkmKiHYSSfuQxqfYmd//X6PxvholpeE=

isolated/slack_test.go

@@ -0,0 +1,23 @@
+package isolated
+
+import (
+	"encoding/json"
+	"fmt"
+	"testing"
+
+	"github.com/slack-go/slack"
+)
+
+func TestTest(t *testing.T) {
+	obj := slack.NewTextBlockObject("plain_text", "here is a url: golang.org", false, false)
+	block := slack.NewSectionBlock(obj, nil, nil)
+	msg := slack.NewBlockMessage(block)
+
+	b, err := json.MarshalIndent(msg, "", "    ")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	fmt.Println(string(b))
+
+}

slack.go

@@ -4,18 +4,20 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net/url"
 	"strings"
 	"time"
 
+	"github.com/PagerDuty/go-pagerduty"
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
 	"github.com/matryer/try"
-
-	"github.com/PagerDuty/go-pagerduty"
-
 	"github.com/slack-go/slack"
+	"mvdan.cc/xurls/v2"
 )
 
+var rxRelaxed = xurls.Relaxed()
+
 type slackUsers []slackUser
 
 func (users slackUsers) findByPDUser(pdUser pagerduty.User) *slackUser {
@@ -276,6 +278,91 @@ func (metaClient *slackMetaClient) updateTopic(ctx context.Context, channelID st
 	return nil
 }
 
+func escapeText(txt string) (string, error) {
+	obj := slack.NewTextBlockObject("mrkdown", "foobarbar", false, false)
+	block := slack.NewSectionBlock(obj, nil, nil)
+	msg := slack.NewBlockMessage(block)
+	msg.
+
+	remainingTxt := escapeAmpersands(txt)
+
+	for {
+		idxPair := rxRelaxed.FindStringIndex(remainingTxt)
+		if idxPair == nil {
+			break
+		}
+
+		startIdx := idxPair[0]
+		if startIdx > 0 && startIdx != '<' && startIdx != '|' {
+			continue
+		}
+
+		rxRelaxed.ReplaceAllString()
+
+		match := remainingTxt[startIdx:indexPair[1]]
+		parsedURL, err := url.Parse(match)
+		if err != nil {
+			return "", fmt.Errorf("failed to parse URL %q: %s", match, err)
+		}
+		if parsedURL.Scheme == "" {
+			strings.ReplaceAll(txt, match, fmt.Sprintf("<http://%s|%s>", match, match))
+		} else {
+			strings.ReplaceAll(txt, match, fmt.Sprintf("<http://%s|%s>", match, match))
+		}
+	}
+
+}
+
+func escapeAmpersands(txt string) string {
+	parts := strings.Split(txt, "&")
+	if len(parts) == 1 {
+		return txt
+	}
+
+	const ampSuffix = "amp;"
+
+	var b strings.Builder
+	for i, part := range parts {
+		b.WriteString(part)
+		if i == len(parts)-1 {
+			break
+		}
+		b.WriteRune('&')
+		nextIdx := i + 1
+		if strings.HasPrefix(parts[nextIdx], ampSuffix) {
+			b.WriteString(ampSuffix)
+			parts[nextIdx] = strings.TrimPrefix(parts[nextIdx], ampSuffix)
+		}
+	}
+
+	return b.String()
+}
+
+func isEncodedURL(txt string, pair []int) bool {
+	left := pair[0] - 1
+	if left == 0 {
+		return false
+	}
+	right := pair[1] + 1
+	if right == len(txt)-1 {
+		return false
+	}
+	return txt[left] == '<' && txt[right] == '>'
+}
+
+func textMatchesAt(txt string, i int, substr string) bool {
+	if len(txt) < i {
+		return false
+	}
+
+	suffix := txt[i:]
+	lenSubstr := len(substr)
+	if len(suffix) < lenSubstr {
+		return false
+	}
+	return suffix[:lenSubstr] == substr
+}
+
 func createSlackUser(apiUser slack.User) slackUser {
 	return slackUser{
 		id:       apiUser.ID,

vendor/modules.txt

@@ -48,3 +48,6 @@ golang.org/x/xerrors/internal
 # gopkg.in/yaml.v2 v2.2.8
 ## explicit
 gopkg.in/yaml.v2
+# mvdan.cc/xurls/v2 v2.5.0
+## explicit; go 1.19
+mvdan.cc/xurls/v2

vendor/mvdan.cc/xurls/v2/.gitattributes

@@ -0,0 +1,2 @@
+# To prevent CRLF breakages on Windows for fragile files, like testdata.
+* -text

vendor/mvdan.cc/xurls/v2/.gitignore

@@ -0,0 +1,3 @@
+cmd/xurls/xurls
+generate/tldsgen/tldsgen
+generate/regexgen/regexgen

vendor/mvdan.cc/xurls/v2/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2015, Daniel Martí. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of the copyright holder nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/mvdan.cc/xurls/v2/README.md

@@ -0,0 +1,37 @@
+# xurls
+
+[![Go Reference](https://pkg.go.dev/badge/mvdan.cc/xurls/v2.svg)](https://pkg.go.dev/mvdan.cc/xurls/v2)
+
+Extract urls from text using regular expressions. Requires Go 1.19 or later.
+
+```go
+import "mvdan.cc/xurls/v2"
+
+func main() {
+	rxRelaxed := xurls.Relaxed()
+	rxRelaxed.FindString("Do gophers live in golang.org?")  // "golang.org"
+	rxRelaxed.FindString("This string does not have a URL") // ""
+
+	rxStrict := xurls.Strict()
+	rxStrict.FindAllString("must have scheme: http://foo.com/.", -1) // []string{"http://foo.com/"}
+	rxStrict.FindAllString("no scheme, no match: foo.com", -1)       // []string{}
+}
+```
+
+Since API is centered around [regexp.Regexp](https://golang.org/pkg/regexp/#Regexp),
+many other methods are available, such as finding the [byte indexes](https://golang.org/pkg/regexp/#Regexp.FindAllIndex)
+for all matches.
+
+The regular expressions are compiled when the API is first called.
+Any subsequent calls will use the same regular expression pointers.
+
+#### cmd/xurls
+
+To install the tool globally:
+
+	go install mvdan.cc/xurls/v2/cmd/xurls@latest
+
+```shell
+$ echo "Do gophers live in http://golang.org?" | xurls
+http://golang.org
+```