package builder

import (
	"strings"
)

// Frontmatter holds parsed page metadata from YAML-style front matter.
type Frontmatter struct {
	Title  string
	Date   string
	Tags   []string
	Layout string // template name without extension, default "base"
	Draft  bool
}

// ParseFrontmatter splits the optional ---...--- block from the markdown body.
// Supports: title, date, tags (comma-list or [a, b]), layout, draft.
func ParseFrontmatter(content string) (Frontmatter, string) {
	fm := Frontmatter{Layout: "base"}
	if !strings.HasPrefix(content, "---") {
		return fm, content
	}
	// Find closing ---
	rest := content[3:]
	end := strings.Index(rest, "\n---")
	if end == -1 {
		return fm, content
	}
	block := strings.TrimSpace(rest[:end])
	body := strings.TrimSpace(rest[end+4:]) // skip \n---

	for _, line := range strings.Split(block, "\n") {
		k, v, ok := strings.Cut(strings.TrimSpace(line), ":")
		if !ok {
			continue
		}
		k = strings.TrimSpace(k)
		v = strings.TrimSpace(v)
		switch k {
		case "title":
			fm.Title = strings.Trim(v, `"'`)
		case "date":
			fm.Date = v
		case "layout":
			fm.Layout = strings.Trim(v, `"'`)
		case "draft":
			fm.Draft = v == "true"
		case "tags":
			fm.Tags = parseTags(v)
		}
	}
	return fm, body
}

func parseTags(v string) []string {
	v = strings.Trim(v, "[] ")
	var tags []string
	for _, p := range strings.Split(v, ",") {
		if t := strings.Trim(strings.TrimSpace(p), `"'`); t != "" {
			tags = append(tags, t)
		}
	}
	return tags
}