grokify/mogo

package markdown

import (
    "fmt"
    "regexp"
)

var (
    rxHTTPURLPrefix *regexp.Regexp = regexp.MustCompile(`^(i?)https?://`)
    rxSkypeLink     *regexp.Regexp = regexp.MustCompile(`<([^><\|]*?)\|([^>]*?)>`)
    rxBacktick3     *regexp.Regexp = regexp.MustCompile(`^\s*` + "```.+```" + `\s*$`)
)

// SkypeToMarkdown converts Skype markup to Markdown. This is specifically
// useful for converting Slack messages to Markdown. The `stripURLAutoLink`
// parameter will remove links when they are within 3 backticks and the
// link innerHTML and URL match. Default is `true`.
func SkypeToMarkdown(input string, stripURLAutoLink bool) string {
    output := input
    backtick3 := rxBacktick3.MatchString(output)
    m := rxSkypeLink.FindAllStringSubmatch(input, -1)
    for _, n := range m {
        rxlink := regexp.MustCompile(regexp.QuoteMeta(n[0]))
        if stripURLAutoLink && backtick3 && n[1] == n[2] && rxHTTPURLPrefix.MatchString(n[1]) {
            output = rxlink.ReplaceAllString(output, n[1])
        } else {
            mkdn := fmt.Sprintf("[%s](%s)", n[2], n[1])
            output = rxlink.ReplaceAllString(output, mkdn)
        }
    }
    return output
}