# Implementation Tasks: WebSocket Chat

## Task Overview

| ID | Task | Status | Blocked By |
|----|------|--------|------------|
| WS-1 | Extend config with Redis URL | pending | - |
| WS-2 | Wire realtime components in main.go | pending | WS-1 |
| WS-3 | Mount WebSocket handler in routes.go | pending | WS-2 |
| WS-4 | Add WebSocket documentation to spec.go | pending | WS-3 |
| WS-5 | Add integration tests for WebSocket chat | pending | WS-3 |

---

## WS-1: Extend config with Redis URL

**Status:** pending

### Description
Add Redis URL configuration to the chat-api service config.

### Files to Modify
- `services/chat-api/internal/config/config.go`

### Implementation Details

Add to the `Config` struct:
```go
// Redis configuration for realtime pub/sub
RedisURL string
```

Add to the `Load()` function:
```go
RedisURL: os.Getenv("REDIS_URL"),
```

### Acceptance Criteria
- [ ] `Config` struct has `RedisURL` field
- [ ] `Load()` reads from `REDIS_URL` environment variable
- [ ] Empty string is valid (disables Redis, uses local-only broadcast)

---

## WS-2: Wire realtime components in main.go

**Status:** pending
**Blocked By:** WS-1

### Description
Initialize the realtime hub and Redis broadcaster in the service entry point.

### Files to Modify
- `services/chat-api/cmd/server/main.go`

### Implementation Details

1. Import required packages:
```go
import (
    "context"
    "github.com/redis/go-redis/v9"
    "git.threesix.ai/jordan/sp3-verify-1770325830/pkg/realtime"
    "git.threesix.ai/jordan/sp3-verify-1770325830/services/chat-api/internal/config"
)
```

2. Load config and create context:
```go
cfg := config.Load()
ctx := context.Background()
```

3. Create hub:
```go
hub := realtime.NewHub(logger)
go hub.Run(ctx)
```

4. Create Redis broadcaster (optional):
```go
var broadcaster realtime.Broadcaster
if cfg.RedisURL != "" {
    opts, err := redis.ParseURL(cfg.RedisURL)
    if err != nil {
        logger.Error("invalid redis url", "error", err)
    } else {
        redisClient := redis.NewClient(opts)
        broadcaster = realtime.NewRedisBroadcaster(redisClient, hub, logger)
        go broadcaster.Run(ctx)
    }
}
```

5. Pass hub and broadcaster to route registration:
```go
api.RegisterRoutes(application, exampleService, hub, broadcaster)
```

### Acceptance Criteria
- [ ] Hub is created and running in a goroutine
- [ ] Redis broadcaster is created when `REDIS_URL` is set
- [ ] Redis broadcaster is nil when `REDIS_URL` is empty
- [ ] Hub and broadcaster are passed to route registration

---

## WS-3: Mount WebSocket handler in routes.go

**Status:** pending
**Blocked By:** WS-2

### Description
Update the route registration to accept realtime components and mount the WebSocket handler.

### Files to Modify
- `services/chat-api/internal/api/routes.go`

### Implementation Details

1. Update function signature:
```go
func RegisterRoutes(
    application *app.App,
    exampleService *service.ExampleService,
    hub realtime.Hub,
    broadcaster realtime.Broadcaster,
) {
```

2. Import realtime package:
```go
import "git.threesix.ai/jordan/sp3-verify-1770325830/pkg/realtime"
```

3. Create and configure WebSocket handler:
```go
wsHandler := realtime.NewHandler(hub, logger, realtime.HandlerConfig{
    Broadcaster: broadcaster,
    OnConnect: func(conn realtime.Connection) {
        logger.Info("websocket client connected",
            "client_id", conn.ID(),
            "user_id", conn.UserID(),
        )
    },
    OnDisconnect: func(conn realtime.Connection) {
        logger.Info("websocket client disconnected",
            "client_id", conn.ID(),
        )
    },
    OnMessage: func(conn realtime.Connection, msg *realtime.Message) *realtime.Message {
        if msg.Type == "" {
            msg.Type = realtime.MessageTypeChat
        }
        return msg
    },
    AuthRequired: cfg.AuthEnabled,
})
```

4. Mount WebSocket routes:
```go
application.Mount("/api/chat-api/ws", wsHandler.Routes())
```

### Acceptance Criteria
- [ ] Function signature accepts `hub` and `broadcaster` parameters
- [ ] WebSocket handler is created with appropriate callbacks
- [ ] Handler is mounted at `/api/chat-api/ws`
- [ ] Auth requirement respects `AUTH_ENABLED` config

---

## WS-4: Add WebSocket documentation to spec.go

**Status:** pending
**Blocked By:** WS-3

### Description
Document the WebSocket endpoint in the OpenAPI specification.

### Files to Modify
- `services/chat-api/internal/api/spec.go`

### Implementation Details

Add WebSocket tag:
```go
spec.WithTag("WebSocket", "Real-time WebSocket endpoints")
```

Add WebSocket path documentation:
```go
spec.AddPath("/api/chat-api/ws", "get", map[string]any{
    "summary":     "WebSocket connection",
    "description": "Upgrades to WebSocket for real-time chat. Messages are broadcast to all connected clients via Redis pub/sub.",
    "tags":        []string{"WebSocket"},
    "responses": map[string]any{
        "101": map[string]any{
            "description": "Switching Protocols - WebSocket upgrade successful",
        },
        "401": openapi.OpResponse("Unauthorized - authentication required", nil),
    },
})

spec.AddPath("/api/chat-api/ws/{room}", "get", map[string]any{
    "summary":     "WebSocket connection to room",
    "description": "Upgrades to WebSocket and joins the specified room. Messages are broadcast only to clients in the same room.",
    "tags":        []string{"WebSocket"},
    "parameters": []map[string]any{
        {
            "name":        "room",
            "in":          "path",
            "required":    true,
            "description": "Room identifier to join",
            "schema":      map[string]any{"type": "string"},
        },
    },
    "responses": map[string]any{
        "101": map[string]any{
            "description": "Switching Protocols - WebSocket upgrade successful",
        },
        "401": openapi.OpResponse("Unauthorized - authentication required", nil),
    },
})
```

### Acceptance Criteria
- [ ] WebSocket tag added to spec
- [ ] `/api/chat-api/ws` endpoint documented
- [ ] `/api/chat-api/ws/{room}` endpoint documented with room parameter
- [ ] Response codes documented (101, 401)

---

## WS-5: Add integration tests for WebSocket chat

**Status:** pending
**Blocked By:** WS-3

### Description
Add tests to verify WebSocket functionality.

### Files to Create
- `services/chat-api/internal/api/handlers/websocket_test.go`

### Implementation Details

Test cases:
1. **Connection upgrade** - Verify WebSocket upgrade succeeds
2. **Message broadcast** - Verify messages sent by one client reach others
3. **Room isolation** - Verify room messages don't leak to other rooms
4. **Ping/pong** - Verify heartbeat mechanism

Example test structure:
```go
package handlers_test

import (
    "net/http"
    "net/http/httptest"
    "testing"
    "time"

    "github.com/gorilla/websocket"
    "git.threesix.ai/jordan/sp3-verify-1770325830/pkg/logging"
    "git.threesix.ai/jordan/sp3-verify-1770325830/pkg/realtime"
)

func TestWebSocket_Connection(t *testing.T) {
    // Create hub
    hub := realtime.NewHub(logging.Nop())
    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()
    go hub.Run(ctx)

    // Create handler
    handler := realtime.NewHandler(hub, logging.Nop(), realtime.HandlerConfig{})

    // Create test server
    server := httptest.NewServer(handler.Routes())
    defer server.Close()

    // Connect WebSocket
    wsURL := "ws" + server.URL[4:] + "/"
    conn, _, err := websocket.DefaultDialer.Dial(wsURL, nil)
    if err != nil {
        t.Fatalf("dial failed: %v", err)
    }
    defer conn.Close()

    // Verify connection count
    time.Sleep(50 * time.Millisecond)
    if hub.ConnectionCount() != 1 {
        t.Errorf("expected 1 connection, got %d", hub.ConnectionCount())
    }
}
```

### Acceptance Criteria
- [ ] Test WebSocket connection upgrade works
- [ ] Test message broadcast to multiple clients
- [ ] Test room-based message isolation
- [ ] All tests pass