package auth

import (
	"regexp"
	"strings"
)

var placeholderPattern = regexp.MustCompile(`\{\{\s*([a-zA-Z0-9_.]+)\s*\}\}`)

// PlaceholderContext holds values used to expand action body placeholders.
type PlaceholderContext struct {
	Host     string
	IP       string
	Username string
	Env      map[string]string
	Secrets  map[string]string
}

// ExpandPlaceholders replaces {{cc.host}}, {{node.ip}}, {{env.NAME}}, etc.
// Unknown or unresolved secrets expand to empty strings.
func ExpandPlaceholders(body string, ctx PlaceholderContext) string {
	return placeholderPattern.ReplaceAllStringFunc(body, func(match string) string {
		submatches := placeholderPattern.FindStringSubmatch(match)
		if len(submatches) < 2 {
			return match
		}
		key := strings.TrimSpace(submatches[1])
		switch key {
		case "cc.host", "node.host":
			return ctx.Host
		case "cc.ip", "node.ip":
			return ctx.IP
		case "node.username":
			return ctx.Username
		default:
			if strings.HasPrefix(key, "env.") {
				name := strings.TrimPrefix(key, "env.")
				if ctx.Env != nil {
					return ctx.Env[name]
				}
				return ""
			}
			if strings.HasPrefix(key, "secret.") {
				name := strings.TrimPrefix(key, "secret.")
				if ctx.Secrets != nil {
					return ctx.Secrets[name]
				}
				return ""
			}
			return ""
		}
	})
}