package registry

import (
	"context"
	"encoding/json"
	"errors"
)

type ToolDescriptor struct {
	Name        string          `json:"name"`
	Description string          `json:"description"`
	InputSchema json.RawMessage `json:"inputSchema"`
}

type Tool interface {
	Descriptor() ToolDescriptor
	Call(ctx context.Context, args json.RawMessage) (json.RawMessage, error)
}

type Registry struct {
	tools map[string]Tool
}

func New() *Registry { return &Registry{tools: map[string]Tool{}} }

func (r *Registry) Register(t Tool) { r.tools[t.Descriptor().Name] = t }

func (r *Registry) Tools() []ToolDescriptor {
	out := make([]ToolDescriptor, 0, len(r.tools))
	for _, t := range r.tools {
		out = append(out, t.Descriptor())
	}
	return out
}

func (r *Registry) Dispatch(ctx context.Context, name string, args json.RawMessage) (json.RawMessage, error) {
	t, ok := r.tools[name]
	if !ok {
		return nil, errors.New("tool not found: " + name)
	}
	return t.Call(ctx, args)
}