package update

import (
	"regexp"
	"strings"
	"time"
)

var (
	bulletLine   = regexp.MustCompile(`^[-*+]\s+(.+)$`)
	markdownLink = regexp.MustCompile(`!?\[([^\]]*)\]\([^)]*\)`)
	boldText     = regexp.MustCompile(`\*\*([^*]+)\*\*|__([^_]+)__`)
	italicText   = regexp.MustCompile(`\*([^*\s][^*]*)\*`)
	inlineCode   = regexp.MustCompile("`([^`]*)`")
)

func BuildNotes(tag string, publishedAt time.Time, body string) ReleaseNotes {
	items := []string{}
	for _, line := range strings.Split(body, "\n") {
		match := bulletLine.FindStringSubmatch(strings.TrimSpace(line))
		if match == nil {
			continue
		}
		if item := plainText(match[1]); item != "" {
			items = append(items, item)
		}
	}
	return ReleaseNotes{Version: tag, ReleasedAt: publishedAt, Items: items}
}

func plainText(markdown string) string {
	text := markdownLink.ReplaceAllString(markdown, "$1")
	text = boldText.ReplaceAllString(text, "$1$2")
	text = italicText.ReplaceAllString(text, "$1")
	text = inlineCode.ReplaceAllString(text, "$1")
	return strings.TrimSpace(text)
}