package tools

import (
	"sync"
)

// registry is the default implementation of Registry.
type registry struct {
	mu    sync.RWMutex
	tools map[string]Tool
	order []string
}

// NewRegistry returns a new empty registry.
func NewRegistry() Registry {
	return &registry{
		tools: make(map[string]Tool),
	}
}

func (r *registry) Register(t Tool) error {
	r.mu.Lock()
	defer r.mu.Unlock()

	if _, exists := r.tools[t.Name]; exists {
		return ErrDuplicateTool
	}

	r.tools[t.Name] = t
	r.order = append(r.order, t.Name)
	return nil
}

func (r *registry) Get(name string) (Tool, bool) {
	r.mu.RLock()
	defer r.mu.RUnlock()

	t, ok := r.tools[name]
	return t, ok
}

func (r *registry) List() []Tool {
	r.mu.RLock()
	defer r.mu.RUnlock()

	out := make([]Tool, len(r.order))
	for i, name := range r.order {
		out[i] = r.tools[name]
	}
	return out
}

func (r *registry) Filter(predicate func(Tool) bool) []Tool {
	r.mu.RLock()
	defer r.mu.RUnlock()

	var result []Tool
	for _, name := range r.order {
		t := r.tools[name]
		if predicate(t) {
			result = append(result, t)
		}
	}
	return result
}