package session

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

	"galaxy/gateway/internal/config"

	"github.com/alicebob/miniredis/v2"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestNewRedisCache(t *testing.T) {
	t.Parallel()

	server := miniredis.RunT(t)

	tests := []struct {
		name    string
		cfg     config.SessionCacheRedisConfig
		wantErr string
	}{
		{
			name: "valid config",
			cfg: config.SessionCacheRedisConfig{
				Addr:          server.Addr(),
				DB:            2,
				KeyPrefix:     "gateway:session:",
				LookupTimeout: 250 * time.Millisecond,
			},
		},
		{
			name: "empty addr",
			cfg: config.SessionCacheRedisConfig{
				LookupTimeout: 250 * time.Millisecond,
			},
			wantErr: "redis addr must not be empty",
		},
		{
			name: "negative db",
			cfg: config.SessionCacheRedisConfig{
				Addr:          server.Addr(),
				DB:            -1,
				LookupTimeout: 250 * time.Millisecond,
			},
			wantErr: "redis db must not be negative",
		},
		{
			name: "non-positive lookup timeout",
			cfg: config.SessionCacheRedisConfig{
				Addr: server.Addr(),
			},
			wantErr: "lookup timeout must be positive",
		},
	}

	for _, tt := range tests {
		tt := tt

		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			cache, err := NewRedisCache(tt.cfg)
			if tt.wantErr != "" {
				require.Error(t, err)
				require.ErrorContains(t, err, tt.wantErr)
				return
			}

			require.NoError(t, err)
			t.Cleanup(func() {
				assert.NoError(t, cache.Close())
			})
		})
	}
}

func TestRedisCachePing(t *testing.T) {
	t.Parallel()

	server := miniredis.RunT(t)
	cache := newTestRedisCache(t, server, config.SessionCacheRedisConfig{})

	require.NoError(t, cache.Ping(context.Background()))
}

func TestRedisCacheLookup(t *testing.T) {
	t.Parallel()

	revokedAtMS := int64(123456789)

	tests := []struct {
		name          string
		cfg           config.SessionCacheRedisConfig
		requestID     string
		seed          func(*testing.T, *miniredis.Miniredis, config.SessionCacheRedisConfig)
		want          Record
		wantErrIs     error
		wantErrText   string
		assertErrText string
	}{
		{
			name:      "active cache hit",
			requestID: "device-session-123",
			cfg: config.SessionCacheRedisConfig{
				KeyPrefix: "gateway:session:",
			},
			seed: func(t *testing.T, server *miniredis.Miniredis, cfg config.SessionCacheRedisConfig) {
				t.Helper()
				setRedisSessionRecord(t, server, cfg.KeyPrefix+"device-session-123", redisRecord{
					DeviceSessionID: "device-session-123",
					UserID:          "user-123",
					ClientPublicKey: "public-key-123",
					Status:          StatusActive,
				})
			},
			want: Record{
				DeviceSessionID: "device-session-123",
				UserID:          "user-123",
				ClientPublicKey: "public-key-123",
				Status:          StatusActive,
			},
		},
		{
			name:      "missing session",
			requestID: "device-session-404",
			cfg: config.SessionCacheRedisConfig{
				KeyPrefix: "gateway:session:",
			},
			wantErrIs:     ErrNotFound,
			assertErrText: "session cache record not found",
		},
		{
			name:      "revoked session",
			requestID: "device-session-revoked",
			cfg: config.SessionCacheRedisConfig{
				KeyPrefix: "gateway:session:",
			},
			seed: func(t *testing.T, server *miniredis.Miniredis, cfg config.SessionCacheRedisConfig) {
				t.Helper()
				setRedisSessionRecord(t, server, cfg.KeyPrefix+"device-session-revoked", redisRecord{
					DeviceSessionID: "device-session-revoked",
					UserID:          "user-777",
					ClientPublicKey: "public-key-777",
					Status:          StatusRevoked,
					RevokedAtMS:     &revokedAtMS,
				})
			},
			want: Record{
				DeviceSessionID: "device-session-revoked",
				UserID:          "user-777",
				ClientPublicKey: "public-key-777",
				Status:          StatusRevoked,
				RevokedAtMS:     &revokedAtMS,
			},
		},
		{
			name:      "malformed json",
			requestID: "device-session-bad-json",
			cfg: config.SessionCacheRedisConfig{
				KeyPrefix: "gateway:session:",
			},
			seed: func(t *testing.T, server *miniredis.Miniredis, cfg config.SessionCacheRedisConfig) {
				t.Helper()
				server.Set(cfg.KeyPrefix+"device-session-bad-json", "{")
			},
			wantErrText: "decode redis session record",
		},
		{
			name:      "unknown status",
			requestID: "device-session-unknown-status",
			cfg: config.SessionCacheRedisConfig{
				KeyPrefix: "gateway:session:",
			},
			seed: func(t *testing.T, server *miniredis.Miniredis, cfg config.SessionCacheRedisConfig) {
				t.Helper()
				setRedisSessionRecord(t, server, cfg.KeyPrefix+"device-session-unknown-status", redisRecord{
					DeviceSessionID: "device-session-unknown-status",
					UserID:          "user-1",
					ClientPublicKey: "public-key-1",
					Status:          Status("paused"),
				})
			},
			wantErrText: `status "paused" is unsupported`,
		},
		{
			name:      "missing required field",
			requestID: "device-session-missing-user",
			cfg: config.SessionCacheRedisConfig{
				KeyPrefix: "gateway:session:",
			},
			seed: func(t *testing.T, server *miniredis.Miniredis, cfg config.SessionCacheRedisConfig) {
				t.Helper()
				setRedisSessionRecord(t, server, cfg.KeyPrefix+"device-session-missing-user", redisRecord{
					DeviceSessionID: "device-session-missing-user",
					ClientPublicKey: "public-key-1",
					Status:          StatusActive,
				})
			},
			wantErrText: "user_id must not be empty",
		},
		{
			name:      "device session id mismatch",
			requestID: "device-session-requested",
			cfg: config.SessionCacheRedisConfig{
				KeyPrefix: "gateway:session:",
			},
			seed: func(t *testing.T, server *miniredis.Miniredis, cfg config.SessionCacheRedisConfig) {
				t.Helper()
				setRedisSessionRecord(t, server, cfg.KeyPrefix+"device-session-requested", redisRecord{
					DeviceSessionID: "device-session-other",
					UserID:          "user-1",
					ClientPublicKey: "public-key-1",
					Status:          StatusActive,
				})
			},
			wantErrText: `does not match requested "device-session-requested"`,
		},
		{
			name:      "key prefix is honored",
			requestID: "device-session-prefixed",
			cfg: config.SessionCacheRedisConfig{
				KeyPrefix: "custom:session:",
			},
			seed: func(t *testing.T, server *miniredis.Miniredis, cfg config.SessionCacheRedisConfig) {
				t.Helper()
				setRedisSessionRecord(t, server, cfg.KeyPrefix+"device-session-prefixed", redisRecord{
					DeviceSessionID: "device-session-prefixed",
					UserID:          "user-prefixed",
					ClientPublicKey: "public-key-prefixed",
					Status:          StatusActive,
				})
				setRedisSessionRecord(t, server, "gateway:session:device-session-prefixed", redisRecord{
					DeviceSessionID: "device-session-prefixed",
					UserID:          "wrong-user",
					ClientPublicKey: "wrong-key",
					Status:          StatusRevoked,
				})
			},
			want: Record{
				DeviceSessionID: "device-session-prefixed",
				UserID:          "user-prefixed",
				ClientPublicKey: "public-key-prefixed",
				Status:          StatusActive,
			},
		},
	}

	for _, tt := range tests {
		tt := tt

		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			server := miniredis.RunT(t)

			cfg := tt.cfg
			cfg.Addr = server.Addr()
			cfg.DB = 0
			cfg.LookupTimeout = 250 * time.Millisecond

			if tt.seed != nil {
				tt.seed(t, server, cfg)
			}

			cache := newTestRedisCache(t, server, cfg)
			record, err := cache.Lookup(context.Background(), tt.requestID)
			if tt.wantErrIs != nil || tt.wantErrText != "" {
				require.Error(t, err)
				if tt.wantErrIs != nil {
					assert.ErrorIs(t, err, tt.wantErrIs)
				}
				if tt.wantErrText != "" {
					assert.ErrorContains(t, err, tt.wantErrText)
				}
				if tt.assertErrText != "" {
					assert.ErrorContains(t, err, tt.assertErrText)
				}
				return
			}

			require.NoError(t, err)
			assert.Equal(t, tt.want, record)
		})
	}
}

func newTestRedisCache(t *testing.T, server *miniredis.Miniredis, cfg config.SessionCacheRedisConfig) *RedisCache {
	t.Helper()

	if cfg.Addr == "" {
		cfg.Addr = server.Addr()
	}
	if cfg.LookupTimeout == 0 {
		cfg.LookupTimeout = 250 * time.Millisecond
	}

	cache, err := NewRedisCache(cfg)
	require.NoError(t, err)

	t.Cleanup(func() {
		assert.NoError(t, cache.Close())
	})

	return cache
}

func setRedisSessionRecord(t *testing.T, server *miniredis.Miniredis, key string, record redisRecord) {
	t.Helper()

	payload, err := json.Marshal(record)
	require.NoError(t, err)

	server.Set(key, string(payload))
}

func TestRedisCacheLookupNilContext(t *testing.T) {
	t.Parallel()

	server := miniredis.RunT(t)
	cache := newTestRedisCache(t, server, config.SessionCacheRedisConfig{})

	_, err := cache.Lookup(context.TODO(), "device-session-123")
	require.Error(t, err)
	assert.False(t, errors.Is(err, ErrNotFound))
	assert.ErrorContains(t, err, "nil context")
}