Add todo mode and replace the plan with TODO.md

internal/todo/todo.go

@@ -0,0 +1,142 @@
+package todo
+
+import (
+	"regexp"
+	"strings"
+
+	"g.fc.run/misc/byre/internal/api"
+)
+
+const File = "TODO.md"
+
+var (
+	heading  = regexp.MustCompile(`^#{1,6}\s+(.*?)\s*#*\s*$`)
+	listItem = regexp.MustCompile(`^(?:[-*+]|\d+[.)])\s+(.*)$`)
+	checkbox = regexp.MustCompile(`^\[([ xX])\]\s+`)
+	fence    = regexp.MustCompile("^\\s*(```|~~~)")
+)
+
+func Parse(src string) []api.TodoItem {
+	items := []api.TodoItem{}
+	section := ""
+	var cur *api.TodoItem
+	body := []string{}
+	inFence := false
+	blank := false
+
+	finish := func() {
+		if cur == nil {
+			return
+		}
+		cur.Body = dedent(body)
+		items = append(items, *cur)
+		cur = nil
+		body = []string{}
+	}
+
+	for _, line := range strings.Split(strings.ReplaceAll(src, "\r\n", "\n"), "\n") {
+		if fence.MatchString(line) {
+			inFence = !inFence
+			if cur != nil {
+				body = append(body, line)
+			}
+			continue
+		}
+		if inFence {
+			if cur != nil {
+				body = append(body, line)
+			}
+			continue
+		}
+
+		if strings.TrimSpace(line) == "" {
+			blank = true
+			if cur != nil {
+				body = append(body, "")
+			}
+			continue
+		}
+		indented := line[0] == ' ' || line[0] == '\t'
+		afterBlank := blank
+		blank = false
+
+		if m := heading.FindStringSubmatch(line); m != nil {
+			finish()
+			section = m[1]
+			continue
+		}
+		if m := listItem.FindStringSubmatch(line); m != nil {
+			finish()
+			title := m[1]
+			box := checkbox.FindStringSubmatch(title)
+			if box != nil && box[1] != " " {
+				continue
+			}
+			title = strings.TrimSpace(checkbox.ReplaceAllString(title, ""))
+			cur = &api.TodoItem{Title: title, Section: section}
+			continue
+		}
+		if cur == nil {
+			continue
+		}
+		if !indented && afterBlank {
+			finish()
+			continue
+		}
+		body = append(body, line)
+	}
+	finish()
+
+	return items
+}
+
+func Find(items []api.TodoItem, title string) (api.TodoItem, bool) {
+	for _, item := range items {
+		if item.Title == title {
+			return item, true
+		}
+	}
+	return api.TodoItem{}, false
+}
+
+func Markdown(item api.TodoItem) string {
+	if item.Body == "" {
+		return "- " + item.Title
+	}
+	lines := []string{"- " + item.Title}
+	for _, line := range strings.Split(item.Body, "\n") {
+		if line == "" {
+			lines = append(lines, "")
+			continue
+		}
+		lines = append(lines, "  "+line)
+	}
+	return strings.Join(lines, "\n")
+}
+
+func dedent(lines []string) string {
+	for len(lines) > 0 && lines[len(lines)-1] == "" {
+		lines = lines[:len(lines)-1]
+	}
+
+	indent := -1
+	for _, line := range lines {
+		if line == "" {
+			continue
+		}
+		n := len(line) - len(strings.TrimLeft(line, " \t"))
+		if indent < 0 || n < indent {
+			indent = n
+		}
+	}
+
+	out := []string{}
+	for _, line := range lines {
+		if line == "" {
+			out = append(out, "")
+			continue
+		}
+		out = append(out, line[indent:])
+	}
+	return strings.Join(out, "\n")
+}