package tools

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"sync"

	"git.bebrik.xyz/Dan4ick/ZovOS_AI/internal/ai"
)

// ToolHandler is the function signature for tool implementations.
type ToolHandler func(ctx context.Context, args json.RawMessage) (string, error)

// ToolDef defines a tool with its metadata and handler.
type ToolDef struct {
	ai.Tool
	Handler ToolHandler
}

// Registry manages all available tools.
type Registry struct {
	mu    sync.RWMutex
	tools map[string]ToolDef
	log   *slog.Logger
}

// NewRegistry creates a new tool registry.
func NewRegistry(log *slog.Logger) *Registry {
	return &Registry{
		tools: make(map[string]ToolDef),
		log:   log,
	}
}

// Register adds a tool to the registry.
func (r *Registry) Register(def ToolDef) {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.tools[def.Name] = def
	r.log.Info("registered tool", "name", def.Name)
}

// Execute runs a tool by name with the given arguments.
func (r *Registry) Execute(ctx context.Context, name string, argsJSON string) (string, error) {
	r.mu.RLock()
	td, ok := r.tools[name]
	r.mu.RUnlock()
	if !ok {
		return "", fmt.Errorf("unknown tool: %s", name)
	}

	r.log.Info("executing tool", "name", name, "args", argsJSON)

	result, err := td.Handler(ctx, json.RawMessage(argsJSON))
	if err != nil {
		r.log.Error("tool execution failed", "name", name, "error", err)
		return fmt.Sprintf("Error: %v", err), nil // return error as result, not as Go error
	}

	r.log.Debug("tool result", "name", name, "result_len", len(result))
	return result, nil
}

// List returns AI tool definitions for all registered tools.
func (r *Registry) List() []ai.Tool {
	r.mu.RLock()
	defer r.mu.RUnlock()
	result := make([]ai.Tool, 0, len(r.tools))
	for _, td := range r.tools {
		result = append(result, td.Tool)
	}
	return result
}

// Names returns names of all registered tools.
func (r *Registry) Names() []string {
	r.mu.RLock()
	defer r.mu.RUnlock()
	names := make([]string, 0, len(r.tools))
	for name := range r.tools {
		names = append(names, name)
	}
	return names
}