package lobbyeventspublisher

import (
	"context"
	"encoding/json"
	"strconv"
	"testing"
	"time"

	"github.com/alicebob/miniredis/v2"
	"github.com/redis/go-redis/v9"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"galaxy/gamemaster/internal/domain/runtime"
	"galaxy/gamemaster/internal/ports"
)

const testStream = "gm:lobby_events"

func newTestPublisher(t *testing.T) (*Publisher, *redis.Client) {
	t.Helper()
	server := miniredis.RunT(t)
	client := redis.NewClient(&redis.Options{Addr: server.Addr()})
	t.Cleanup(func() { _ = client.Close() })
	publisher, err := NewPublisher(Config{Client: client, Stream: testStream})
	require.NoError(t, err)
	return publisher, client
}

func TestNewPublisherValidation(t *testing.T) {
	t.Run("nil client", func(t *testing.T) {
		_, err := NewPublisher(Config{Stream: testStream})
		require.Error(t, err)
	})
	t.Run("empty stream", func(t *testing.T) {
		client := redis.NewClient(&redis.Options{Addr: "127.0.0.1:0"})
		t.Cleanup(func() { _ = client.Close() })
		_, err := NewPublisher(Config{Client: client})
		require.Error(t, err)
	})
}

func TestPublishSnapshotUpdateHappyPath(t *testing.T) {
	publisher, client := newTestPublisher(t)

	occurredAt := time.Date(2026, 4, 27, 12, 0, 0, 0, time.UTC)
	msg := ports.RuntimeSnapshotUpdate{
		GameID:              "game-1",
		CurrentTurn:         17,
		RuntimeStatus:       runtime.StatusRunning,
		EngineHealthSummary: "healthy",
		PlayerTurnStats: []ports.PlayerTurnStats{
			{UserID: "user-1", Planets: 4, Population: 12000},
			{UserID: "user-2", Planets: 3, Population: 9000},
		},
		OccurredAt: occurredAt,
	}
	require.NoError(t, publisher.PublishSnapshotUpdate(context.Background(), msg))

	entries, err := client.XRange(context.Background(), testStream, "-", "+").Result()
	require.NoError(t, err)
	require.Len(t, entries, 1)
	values := entries[0].Values
	assert.Equal(t, "runtime_snapshot_update", values[fieldEventType])
	assert.Equal(t, "game-1", values[fieldGameID])
	assert.Equal(t, "17", values[fieldCurrentTurn])
	assert.Equal(t, "running", values[fieldRuntimeStatus])
	assert.Equal(t, "healthy", values[fieldEngineHealthSummary])
	assert.Equal(t, strconv.FormatInt(occurredAt.UnixMilli(), 10), values[fieldOccurredAtMS])

	statsRaw, ok := values[fieldPlayerTurnStats].(string)
	require.True(t, ok)
	var stats []playerTurnStatEnvelope
	require.NoError(t, json.Unmarshal([]byte(statsRaw), &stats))
	assert.Equal(t, []playerTurnStatEnvelope{
		{UserID: "user-1", Planets: 4, Population: 12000},
		{UserID: "user-2", Planets: 3, Population: 9000},
	}, stats)
}

func TestPublishSnapshotUpdateEmptyStatsBecomesArray(t *testing.T) {
	publisher, client := newTestPublisher(t)
	msg := ports.RuntimeSnapshotUpdate{
		GameID:              "g",
		CurrentTurn:         0,
		RuntimeStatus:       runtime.StatusStarting,
		EngineHealthSummary: "",
		OccurredAt:          time.Now().UTC(),
	}
	require.NoError(t, publisher.PublishSnapshotUpdate(context.Background(), msg))

	entries, err := client.XRange(context.Background(), testStream, "-", "+").Result()
	require.NoError(t, err)
	require.Len(t, entries, 1)
	assert.Equal(t, "[]", entries[0].Values[fieldPlayerTurnStats])
}

func TestPublishSnapshotUpdateRejectsInvalid(t *testing.T) {
	publisher, client := newTestPublisher(t)
	require.Error(t, publisher.PublishSnapshotUpdate(context.Background(), ports.RuntimeSnapshotUpdate{}))

	entries, err := client.XRange(context.Background(), testStream, "-", "+").Result()
	require.NoError(t, err)
	assert.Empty(t, entries, "invalid messages must not reach the stream")
}

func TestPublishGameFinishedHappyPath(t *testing.T) {
	publisher, client := newTestPublisher(t)

	finishedAt := time.Date(2026, 4, 28, 8, 30, 0, 0, time.UTC)
	msg := ports.GameFinished{
		GameID:          "game-1",
		FinalTurnNumber: 42,
		RuntimeStatus:   runtime.StatusFinished,
		PlayerTurnStats: []ports.PlayerTurnStats{
			{UserID: "user-1", Planets: 6, Population: 25000},
			{UserID: "user-2", Planets: 0, Population: 0},
		},
		FinishedAt: finishedAt,
	}
	require.NoError(t, publisher.PublishGameFinished(context.Background(), msg))

	entries, err := client.XRange(context.Background(), testStream, "-", "+").Result()
	require.NoError(t, err)
	require.Len(t, entries, 1)
	values := entries[0].Values
	assert.Equal(t, "game_finished", values[fieldEventType])
	assert.Equal(t, "game-1", values[fieldGameID])
	assert.Equal(t, "42", values[fieldFinalTurnNumber])
	assert.Equal(t, "finished", values[fieldRuntimeStatus])
	assert.Equal(t, strconv.FormatInt(finishedAt.UnixMilli(), 10), values[fieldFinishedAtMS])

	_, hasOccurred := values[fieldOccurredAtMS]
	assert.False(t, hasOccurred, "game_finished must not carry occurred_at_ms")
	_, hasCurrentTurn := values[fieldCurrentTurn]
	assert.False(t, hasCurrentTurn, "game_finished must not carry current_turn")
	_, hasHealth := values[fieldEngineHealthSummary]
	assert.False(t, hasHealth, "game_finished must not carry engine_health_summary")
}

func TestPublishGameFinishedRejectsBadStatus(t *testing.T) {
	publisher, client := newTestPublisher(t)
	require.Error(t, publisher.PublishGameFinished(context.Background(), ports.GameFinished{
		GameID:          "g",
		FinalTurnNumber: 1,
		RuntimeStatus:   runtime.StatusRunning, // wrong status
		FinishedAt:      time.Now().UTC(),
	}))

	entries, err := client.XRange(context.Background(), testStream, "-", "+").Result()
	require.NoError(t, err)
	assert.Empty(t, entries)
}

func TestTimestampsNormalisedToUTC(t *testing.T) {
	publisher, client := newTestPublisher(t)
	loc, err := time.LoadLocation("Asia/Tokyo")
	require.NoError(t, err)

	msg := ports.RuntimeSnapshotUpdate{
		GameID:        "g",
		CurrentTurn:   1,
		RuntimeStatus: runtime.StatusRunning,
		OccurredAt:    time.Date(2026, 4, 27, 21, 0, 0, 0, loc),
	}
	require.NoError(t, publisher.PublishSnapshotUpdate(context.Background(), msg))

	entries, err := client.XRange(context.Background(), testStream, "-", "+").Result()
	require.NoError(t, err)
	require.Len(t, entries, 1)
	wantMs := msg.OccurredAt.UTC().UnixMilli()
	assert.Equal(t, strconv.FormatInt(wantMs, 10), entries[0].Values[fieldOccurredAtMS])
}

func TestRejectsNilContext(t *testing.T) {
	publisher, _ := newTestPublisher(t)
	//nolint:staticcheck // explicitly testing nil-context rejection.
	err := publisher.PublishSnapshotUpdate(nil, ports.RuntimeSnapshotUpdate{
		GameID:        "g",
		CurrentTurn:   0,
		RuntimeStatus: runtime.StatusStarting,
		OccurredAt:    time.Now().UTC(),
	})
	require.Error(t, err)
}