package shortcuts

import (
	"regexp"
	"strings"
	"sync"

	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/config"
)

// compiled caches rewrite patterns: Normalize runs for every cache entry on each lookup.
var compiled sync.Map // pattern → *regexp.Regexp

func rewritePattern(pattern string) *regexp.Regexp {
	if re, ok := compiled.Load(pattern); ok {
		return re.(*regexp.Regexp)
	}
	re, err := regexp.Compile(pattern)
	if err != nil {
		return nil // rejected by config.Load already
	}
	compiled.Store(pattern, re)
	return re
}

// Normalize strips configured domain suffixes, applies rewrite rules in order, and
// optionally strips hyphens. The result is lowercased for case-insensitive comparison.
func Normalize(name string, cfg config.ShortcutsConfig) string {
	s := strings.ToLower(name)
	for _, domain := range cfg.Domains {
		suffix := strings.ToLower(domain)
		if !strings.HasPrefix(suffix, ".") {
			suffix = "." + suffix
		}
		if strings.HasSuffix(s, suffix) {
			s = s[:len(s)-len(suffix)]
			break
		}
	}
	for _, rewrite := range cfg.Rewrites {
		if re := rewritePattern(rewrite.Pattern); re != nil {
			s = re.ReplaceAllString(s, rewrite.Replace)
		}
	}
	if cfg.StripHyphens {
		s = strings.ReplaceAll(s, "-", "")
	}
	return s
}

// MakeNormalizer returns a closure bound to cfg, suitable for Cache.GetByShortcut.
func MakeNormalizer(cfg config.ShortcutsConfig) func(string) string {
	return func(name string) string {
		return Normalize(name, cfg)
	}
}

// AliasName returns a shell-safe alias name for the given host.
// It normalizes the name (strips configured domains, applies rewrites, optionally strips hyphens) then
// replaces any remaining dots with underscores so the result is a valid identifier.
func AliasName(name string, cfg config.ShortcutsConfig) string {
	s := Normalize(name, cfg)
	return strings.NewReplacer(".", "_", "/", "_").Replace(s)
}