package app

import (
	"context"
	"errors"
	"log/slog"
	"reflect"
	"testing"
	"time"

	"gitea.nik4nao.com/nik/home-services/ai-gateway/internal/core/domain"
	"gitea.nik4nao.com/nik/home-services/ai-gateway/internal/core/ports/driven"
)

type fakeLLM struct {
	generate func(context.Context, string) (string, error)
}

func (f *fakeLLM) Generate(ctx context.Context, prompt string) (string, error) {
	return f.generate(ctx, prompt)
}

type fakeHA struct {
	lights         []driven.Light
	listErr        error
	turnOnErr      error
	turnOffErr     error
	lastTurnOnID   string
	lastTurnOffID  string
	lastTurnParams map[string]string
	listCalls      int
}

func (f *fakeHA) TurnOnLight(ctx context.Context, entity string, params map[string]string) error {
	f.lastTurnOnID = entity
	f.lastTurnParams = params
	return f.turnOnErr
}

func (f *fakeHA) TurnOffLight(ctx context.Context, entity string) error {
	f.lastTurnOffID = entity
	return f.turnOffErr
}

func (f *fakeHA) ListLights(ctx context.Context) ([]driven.Light, error) {
	f.listCalls++
	if f.listErr != nil {
		return nil, f.listErr
	}
	return append([]driven.Light(nil), f.lights...), nil
}

func TestQueryAppTurnOnLight(t *testing.T) {
	ha := &fakeHA{lights: []driven.Light{{EntityID: "light.kitchen", FriendlyName: "Kitchen", State: "off"}}}
	cache := domain.NewLightCache(time.Hour, ha.ListLights)
	app := NewQueryApp(&fakeLLM{
		generate: func(ctx context.Context, prompt string) (string, error) {
			return `{"intent":"turn_on_light","entity":"Kitchen","params":{"brightness":"80"},"reply":"Turning on Kitchen."}`, nil
		},
	}, ha, cache, slog.Default())

	got, err := app.Query(context.Background(), "turn on kitchen")
	if err != nil {
		t.Fatalf("Query() error = %v", err)
	}
	if got.Intent != domain.IntentTurnOnLight || !got.ActionTaken || got.Reply != "Turning on Kitchen." {
		t.Fatalf("Query() = %+v", got)
	}
	if ha.lastTurnOnID != "light.kitchen" {
		t.Fatalf("TurnOnLight entity = %q", ha.lastTurnOnID)
	}
	if !reflect.DeepEqual(ha.lastTurnParams, map[string]string{"brightness": "80"}) {
		t.Fatalf("TurnOnLight params = %#v", ha.lastTurnParams)
	}
}

func TestQueryAppInvalidJSON(t *testing.T) {
	ha := &fakeHA{lights: []driven.Light{{EntityID: "light.kitchen", FriendlyName: "Kitchen", State: "off"}}}
	app := NewQueryApp(&fakeLLM{
		generate: func(ctx context.Context, prompt string) (string, error) {
			return `not-json`, nil
		},
	}, ha, domain.NewLightCache(time.Hour, ha.ListLights), slog.Default())

	got, err := app.Query(context.Background(), "turn on kitchen")
	if err != nil {
		t.Fatalf("Query() error = %v", err)
	}
	if got.Reply != "I didn't understand that." || got.ActionTaken {
		t.Fatalf("Query() = %+v", got)
	}
	if ha.lastTurnOnID != "" {
		t.Fatalf("expected no HA call, got %q", ha.lastTurnOnID)
	}
}

func TestQueryAppIntentNone(t *testing.T) {
	ha := &fakeHA{lights: []driven.Light{{EntityID: "light.kitchen", FriendlyName: "Kitchen", State: "off"}}}
	app := NewQueryApp(&fakeLLM{
		generate: func(ctx context.Context, prompt string) (string, error) {
			return `{"intent":"none","entity":"","params":{},"reply":"Hello there."}`, nil
		},
	}, ha, domain.NewLightCache(time.Hour, ha.ListLights), slog.Default())

	got, err := app.Query(context.Background(), "hello")
	if err != nil {
		t.Fatalf("Query() error = %v", err)
	}
	if got.Reply != "Hello there." || got.ActionTaken {
		t.Fatalf("Query() = %+v", got)
	}
}

func TestQueryAppHAFailure(t *testing.T) {
	ha := &fakeHA{
		lights:    []driven.Light{{EntityID: "light.kitchen", FriendlyName: "Kitchen", State: "off"}},
		turnOnErr: errors.New("boom"),
	}
	app := NewQueryApp(&fakeLLM{
		generate: func(ctx context.Context, prompt string) (string, error) {
			return `{"intent":"turn_on_light","entity":"light.kitchen","params":{},"reply":"Turning on Kitchen."}`, nil
		},
	}, ha, domain.NewLightCache(time.Hour, ha.ListLights), slog.Default())

	got, err := app.Query(context.Background(), "turn on kitchen")
	if err != nil {
		t.Fatalf("Query() error = %v", err)
	}
	if got.Reply != "I couldn't reach Home Assistant right now." || got.ActionTaken {
		t.Fatalf("Query() = %+v", got)
	}
}

func TestQueryAppListLights(t *testing.T) {
	ha := &fakeHA{lights: []driven.Light{{EntityID: "light.kitchen", FriendlyName: "Kitchen", State: "on"}}}
	app := NewQueryApp(&fakeLLM{
		generate: func(ctx context.Context, prompt string) (string, error) {
			return `{"intent":"list_lights","entity":"","params":{},"reply":""}`, nil
		},
	}, ha, domain.NewLightCache(time.Hour, ha.ListLights), slog.Default())

	got, err := app.Query(context.Background(), "what lights exist")
	if err != nil {
		t.Fatalf("Query() error = %v", err)
	}
	want := "Known lights:\n- Kitchen (light.kitchen) [on]"
	if got.Reply != want || got.ActionTaken {
		t.Fatalf("Query() = %+v", got)
	}
}

func TestLightCacheRefreshAfterTTL(t *testing.T) {
	ha := &fakeHA{lights: []driven.Light{{EntityID: "light.kitchen", FriendlyName: "Kitchen", State: "off"}}}
	cache := domain.NewLightCache(10*time.Millisecond, ha.ListLights)

	if _, err := cache.Get(context.Background()); err != nil {
		t.Fatalf("Get() error = %v", err)
	}
	time.Sleep(20 * time.Millisecond)
	if _, err := cache.Get(context.Background()); err != nil {
		t.Fatalf("Get() error = %v", err)
	}
	if ha.listCalls < 2 {
		t.Fatalf("ListLights calls = %d, want at least 2", ha.listCalls)
	}
}