package devicemesh

import (
	"context"
	"encoding/json"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
)

func TestToolRegistry_RegisterListGet(t *testing.T) {
	reg := NewToolRegistry(nil)
	reg.Register(ToolSpec{Name: "a", Capability: "x.a"})
	reg.Register(ToolSpec{Name: "b", Capability: "x.b"})

	got, ok := reg.Get("a")
	if !ok {
		t.Fatalf("Get(a) not found")
	}
	if got.Capability != "x.a" {
		t.Errorf("capability: %q", got.Capability)
	}

	names := reg.Names()
	if len(names) != 2 || names[0] != "a" || names[1] != "b" {
		t.Errorf("Names sort: %v", names)
	}
}

func TestToolRegistry_Call_UnknownTool(t *testing.T) {
	reg := NewToolRegistry(NewClient("http://nowhere.invalid"))
	_, err := reg.Call(context.Background(), "no.such.tool", nil)
	if err == nil {
		t.Fatalf("expected error for unknown tool")
	}
	if !strings.Contains(err.Error(), "unknown tool") {
		t.Errorf("error message: %v", err)
	}
}

func TestToolRegistry_Call_NilClient(t *testing.T) {
	reg := NewToolRegistry(nil)
	reg.Register(ToolSpec{Name: "x", Capability: "x.y"})
	_, err := reg.Call(context.Background(), "x", nil)
	if err == nil {
		t.Fatalf("expected error when client is nil")
	}
}

func TestToolRegistry_Call_InvalidInput(t *testing.T) {
	reg := NewToolRegistry(NewClient("http://nowhere.invalid"))
	reg.Register(ToolSpec{
		Name:       "needs_string",
		Capability: "x.y",
		InputSchema: map[string]any{
			"type":     "object",
			"required": []string{"foo"},
			"properties": map[string]any{
				"foo": map[string]any{"type": "string"},
			},
			"additionalProperties": false,
		},
	})

	// Missing required
	_, err := reg.Call(context.Background(), "needs_string", map[string]any{})
	if err == nil {
		t.Errorf("expected error for missing required field")
	}

	// Wrong type
	_, err = reg.Call(context.Background(), "needs_string", map[string]any{"foo": 42})
	if err == nil {
		t.Errorf("expected error for wrong type")
	}

	// Extra field
	_, err = reg.Call(context.Background(), "needs_string", map[string]any{"foo": "bar", "extra": 1})
	if err == nil {
		t.Errorf("expected error for additional property")
	}
}

func TestToolRegistry_Call_HappyPath(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		var req CapabilityRequest
		body, _ := io.ReadAll(r.Body)
		_ = json.Unmarshal(body, &req)
		// Echo back the args under "received".
		_ = json.NewEncoder(w).Encode(CapabilityResponse{
			RequestID: req.RequestID,
			OK:        true,
			Result:    map[string]any{"received": req.Args},
		})
	}))
	defer srv.Close()

	reg := NewToolRegistry(NewClient(srv.URL))
	reg.Register(ToolSpec{
		Name:       "echo",
		Capability: "x.echo",
		InputSchema: map[string]any{
			"type":     "object",
			"required": []string{"msg"},
			"properties": map[string]any{
				"msg": map[string]any{"type": "string"},
			},
		},
		ArgMapping: func(in map[string]any) (map[string]any, error) {
			return map[string]any{"upper_msg": strings.ToUpper(in["msg"].(string))}, nil
		},
		ResultMapping: func(r map[string]any) (any, error) {
			received := r["received"].(map[string]any)
			return received["upper_msg"], nil
		},
	})

	out, err := reg.Call(context.Background(), "echo", map[string]any{"msg": "hola"})
	if err != nil {
		t.Fatalf("call: %v", err)
	}
	if out != "HOLA" {
		t.Errorf("expected HOLA, got %v", out)
	}
}

func TestToolRegistry_Call_DeviceErrorPropagates(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_ = json.NewEncoder(w).Encode(CapabilityResponse{
			OK:    false,
			Error: "binary not whitelisted",
		})
	}))
	defer srv.Close()

	reg := NewToolRegistry(NewClient(srv.URL))
	reg.Register(ToolSpec{Name: "exec", Capability: "shell.exec"})
	_, err := reg.Call(context.Background(), "exec", nil)
	if err == nil {
		t.Fatalf("expected device-side error to propagate")
	}
	if !strings.Contains(err.Error(), "binary not whitelisted") {
		t.Errorf("error message lost: %v", err)
	}
}