refactor(core): replace SocialMediaService with GeneratePostService, add message fetching and JSON:API resources

- Removed `SocialMediaService` and migrated core post generation logic to `GeneratePostService`.
- Added `GetAllChatMessagesAction` for fetching chat history.
- Introduced `MessageDto`, `MessageResource`, and `MessageCollection` for consistent backend API responses.
- Updated frontend state and services to support JSON:API-compliant chat messages and history retrieval.
- Improved typings and casting for chat message data.

.idea/laravel-idea.xml

@@ -12,6 +12,7 @@
           <map>
             <entry key="createEloquentScope:namespace" value="Models\Scopes" />
             <entry key="createFormRequestDto:namespace" value="Data" />
+            <entry key="createJsonResource:classSuffix" value="Resource" />
             <entry key="createModel:namespace" value="Models" />
           </map>
         </option>

backend/app/Actions/Chats/GetAllChatMessagesAction.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace App\Actions\Chats;
+
+use App\Data\Chats\MessageDto;
+use App\Models\Chat;
+use Illuminate\Pagination\AbstractPaginator;
+use Illuminate\Pagination\LengthAwarePaginator;
+
+class GetAllChatMessagesAction
+{
+    public function messages(Chat $chat): AbstractPaginator|LengthAwarePaginator
+    {
+        $messages = $chat->messages()->oldest()->paginate();
+
+        return $messages->through(fn ($m) => MessageDto::fromModel($m));
+    }
+}

backend/app/Actions/Chats/StoreChatMessageAction.php

@@ -1,18 +0,0 @@
-<?php
-
-namespace App\Actions\Chats;
-
-use App\Enums\Chats\ChatRoles;
-use App\Models\Chat;
-use Illuminate\Database\Eloquent\Model;
-
-final readonly class StoreChatMessageAction
-{
-    public function store(Chat $chat, ChatRoles $role, string $message): Model
-    {
-        return $chat->messages()->create([
-            'role' => $role->value,
-            'content' => $message,
-        ]);
-    }
-}

backend/app/Data/Chats/MessageDto.php

@@ -0,0 +1,67 @@
+<?php
+
+namespace App\Data\Chats;
+
+use App\Models\ChatMessage;
+use Carbon\CarbonInterface;
+use Illuminate\Database\Eloquent\Model;
+use Laravel\Ai\Messages\AssistantMessage;
+use Laravel\Ai\Responses\AgentResponse;
+use Laravel\Ai\Responses\TextResponse;
+
+final readonly class MessageDto
+{
+    public function __construct(
+        public string $id,
+        public string $conversationId,
+        public string $role,
+        public string $content,
+        public string $agent,
+        public array $attachments,
+        public array $toolCalls,
+        public array $toolResults,
+        public array $usage,
+        public array $meta,
+        public CarbonInterface $createdAt,
+        public CarbonInterface $updatedAt,
+    ) {}
+
+    public static function fromModel(ChatMessage|Model $message): MessageDto
+    {
+        return new self(
+            id: $message->id,
+            conversationId: $message->conversation_id,
+            role: $message->role,
+            content: $message->content,
+            agent: $message->agent,
+            attachments: $message->attachments,
+            toolCalls: $message->tool_calls,
+            toolResults: $message->tool_results,
+            usage: $message->usage,
+            meta: $message->meta,
+            createdAt: $message->created_at,
+            updatedAt: $message->updated_at,
+        );
+    }
+
+    public static function fromAgentResponse(AgentResponse|TextResponse $response, string $agent): MessageDto
+    {
+        /** @var AssistantMessage $message */
+        $message = $response->messages->first();
+
+        return new self(
+            id: $response->invocationId,
+            conversationId: $response->conversationId,
+            role: $message->role->value,
+            content: $message->content,
+            agent: $agent,
+            attachments: [],
+            toolCalls: $response->toolCalls->toArray(),
+            toolResults: $response->toolResults->toArray(),
+            usage: $response->usage->toArray(),
+            meta: $response->meta->toArray(),
+            createdAt: now(),
+            updatedAt: now(),
+        );
+    }
+}

backend/app/Http/Controllers/Chats/ChatController.php

@@ -10,7 +10,7 @@
 
 class ChatController extends Controller
 {
-    public function index(Request $request) {}
+    public function index(Chat $chat) {}
 
     public function store(CreateChatRequest $request, CreateChatAction $createChatAction)
     {

backend/app/Http/Controllers/Chats/ChatMessageController.php

@@ -2,22 +2,30 @@
 
 namespace App\Http\Controllers\Chats;
 
+use App\Actions\Chats\GetAllChatMessagesAction;
 use App\Http\Controllers\Controller;
 use App\Http\Requests\Chats\GeneratePostRequest;
-use App\Http\Resources\Chats\GeneratedPostResource;
+use App\Http\Resources\Chats\MessageResource;
 use App\Models\Chat;
-use App\Services\SocialMediaService;
+use App\Services\GeneratePostService;
-use Illuminate\Http\Request;
 use Illuminate\Routing\Attributes\Controllers\Authorize;
+use Illuminate\Routing\Attributes\Controllers\Middleware;
 
+#[Middleware('auth:sanctum')]
 class ChatMessageController extends Controller
 {
-    #[Authorize('update', 'chat')]
+    /**
-    public function store(GeneratePostRequest $request, Chat $chat, SocialMediaService $socialMediaService)
+     * Get Chat History of a Chat
+     */
+    #[Authorize('view', 'chat')]
+    public function index(Chat $chat, GetAllChatMessagesAction $getAllMessages)
     {
-        return new GeneratedPostResource(
+        return MessageResource::collection($getAllMessages->messages($chat));
-            $socialMediaService
+    }
-                ->generatePostWithImage($request->input('prompt'), $chat)
+
-        );
+    #[Authorize('update', 'chat')]
+    public function store(GeneratePostRequest $request, Chat $chat, GeneratePostService $socialMediaService)
+    {
+        return new MessageResource($socialMediaService->generate($request->input('prompt'), $chat));
     }
 }

backend/app/Http/Resources/Chats/MessageCollection.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace App\Http\Resources\Chats;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Attributes\Collects;
+use Illuminate\Http\Resources\Json\ResourceCollection;
+
+#[Collects(MessageResource::class)]
+class MessageCollection extends ResourceCollection
+{
+    public function toArray(Request $request): array
+    {
+        return [
+            'data' => $this->collection,
+        ];
+    }
+}

backend/app/Http/Resources/Chats/MessageResource.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Http\Resources\Chats;
+
+use App\Data\Chats\MessageDto;
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\JsonApi\JsonApiResource;
+
+/**
+ * @property MessageDto $resource
+ */
+class MessageResource extends JsonApiResource
+{
+    public function type(): string
+    {
+        return 'messages';
+    }
+
+    public function resolveResourceIdentifier($request): string
+    {
+        return $this->resource->id;
+    }
+
+    public function toAttributes(Request $request): array
+    {
+        return [
+            'role' => $this->resource->role,
+            'content' => $this->resource->content,
+            'attachments' => $this->resource->attachments,
+            'createdAt' => $this->resource->createdAt->toIso8601String(),
+        ];
+    }
+}

backend/app/Models/ChatMessage.php

@@ -8,7 +8,7 @@
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 
-#[Fillable(['conversation_id', 'agent_id', 'role', 'content', 'attachment', 'tool_calls', 'tool_results', 'usage', 'meta', 'content', 'user_id'])]
+#[Fillable(['conversation_id', 'agent_id', 'role', 'content', 'attachments', 'tool_calls', 'tool_results', 'usage', 'meta', 'content', 'user_id'])]
 #[Table('agent_conversation_messages')]
 class ChatMessage extends Model
 {
@@ -18,4 +18,12 @@ public function chat(): BelongsTo
     {
         return $this->belongsTo(Chat::class, 'conversation_id', 'id');
     }
+
+    protected $casts = [
+        'attachments' => 'array',
+        'meta' => 'array',
+        'usage' => 'array',
+        'tool_calls' => 'array',
+        'tool_results' => 'array',
+    ];
 }

backend/app/Services/GeneratePostService.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Services;
+
+use App\Ai\Agents\ContentWriterAgent;
+use App\Data\Chats\MessageDto;
+use App\Models\Chat;
+
+class GeneratePostService
+{
+    public function __construct(
+        private ContentWriterAgent $contentWriterAgent,
+    ) {}
+
+    /**
+     * Generate a social media post with an image.
+     * We are not using database transactions here because we do not want to delete the user prompt
+     * if any of the ai agents fails.
+     */
+    public function generate(string $prompt, Chat $chat): MessageDto
+    {
+        $socialMediaResponse = $this->contentWriterAgent
+            ->continue($chat->id, $chat->user)
+            ->prompt($prompt);
+
+        return MessageDto::fromAgentResponse($socialMediaResponse, ContentWriterAgent::class);
+    }
+}

backend/app/Services/SocialMediaService.php

@@ -1,35 +0,0 @@
-<?php
-
-namespace App\Services;
-
-use App\Actions\Chats\StoreChatMessageAction;
-use App\Ai\Agents\ContentWriterAgent;
-use App\Ai\Agents\CreativeDirectorAgent;
-use App\Data\Chats\SocialMediaPostResponseDto;
-use App\Models\Chat;
-
-readonly class SocialMediaService
-{
-    public function __construct(
-        private ContentWriterAgent $contentWriterAgent,
-        private CreativeDirectorAgent $creativeDirectorAgent,
-        private StoreChatMessageAction $chatMessage,
-    ) {}
-
-    /**
-     * Generate a social media post with an image.
-     * We are not using database transactions here because we do not want to delete the user prompt
-     * if any of the ai agents fails.
-     */
-    public function generatePostWithImage(string $prompt, Chat $chat): SocialMediaPostResponseDto
-    {
-        $socialMediaResponse = $this->contentWriterAgent->forUser($chat->user)->prompt($prompt);
-        $postText = $socialMediaResponse->text;
-
-        // Generate image prompt via creative director agent
-        $imagePromptResponse = $this->creativeDirectorAgent->prompt($postText);
-        $imagePrompt = $imagePromptResponse->text;
-
-        return new SocialMediaPostResponseDto($socialMediaResponse->conversationId, $postText, $imagePrompt, now());
-    }
-}

frontend/src/app/chat/chat-service.ts

@@ -1,7 +1,7 @@
 import { inject, Injectable } from '@angular/core';
 import { HttpClient } from '@angular/common/http';
 import { API_URL } from '../core/tokens/api-urls';
-import { MessageResponse, NewChatResponse } from './chat.types';
+import { MessageCollection, MessageResponse, NewChatResponse } from './chat.types';
 
 @Injectable({
   providedIn: 'root',
@@ -19,4 +19,8 @@ export class ChatService {
       prompt: message,
     });
   }
+
+  public getMessages(id: string) {
+    return this.http.get<MessageCollection>(`${this.apiUrl}/chats/${id}/messages`);
+  }
 }

frontend/src/app/chat/chat.html

@@ -11,16 +11,16 @@
     @for (msg of chatStore.messages(); track msg.id) {
       <div
         class="flex flex-col max-w-[80%] animate-[messageAppear_0.5s_cubic-bezier(0.16,1,0.3,1)]"
-        [ngClass]="msg.role === 'user' ? 'self-end items-end' : 'self-start items-start'"
+        [ngClass]="msg.attributes.role === 'user' ? 'self-end items-end' : 'self-start items-start'"
       >
         <div
           class="px-5 py-4 rounded-2xl text-base leading-relaxed shadow-[0_4px_15px_rgba(0,0,0,0.1)] relative whitespace-pre-wrap"
-          [ngClass]="msg.role === 'user' ? 'bg-gradient-to-br from-indigo-500 to-purple-600 text-white rounded-br-sm' : 'bg-white/10 border border-white/5 text-slate-200 rounded-bl-sm backdrop-blur-md'"
+          [ngClass]="msg.attributes.role === 'user' ? 'bg-gradient-to-br from-indigo-500 to-purple-600 text-white rounded-br-sm' : 'bg-white/10 border border-white/5 text-slate-200 rounded-bl-sm backdrop-blur-md'"
         >
-          {{ msg.content }}
+          {{ msg.attributes.content }}
         </div>
         <div class="text-xs text-slate-500 mt-2 px-1">
-          {{ msg.timestamp | date:'shortTime' }}
+          {{ msg.attributes.createdAt | date:'shortTime' }}
         </div>
       </div>
     }

frontend/src/app/chat/chat.store.ts

@@ -1,18 +1,23 @@
-import { signalStore, withState, withMethods, patchState } from '@ngrx/signals';
+import { patchState, signalStore, withMethods, withState } from '@ngrx/signals';
 import { inject } from '@angular/core';
 import { HttpErrorResponse } from '@angular/common/http';
 import { ChatService } from './chat-service';
-import { ChatState, Message } from './chat.types';
+import { ChatState, Message, MessageResponse } from './chat.types';
 import { lastValueFrom } from 'rxjs';
 import { Router } from '@angular/router';
+import { JsonApiResource } from '../core/types/api';
 
 const initialState: ChatState = {
   messages: [
     {
-      id: 'welcome',
+      id: 'null',
-      role: 'ai',
+      type: 'messages',
+      attributes: {
+        role: 'assistant',
         content: "What's you want to post today?",
-      timestamp: new Date(),
+        attachments: [],
+        createdAt: new Date(),
+      },
     },
   ],
   isLoading: false,
@@ -39,6 +44,21 @@ export const ChatStore = signalStore(
         throw error;
       }
     };
+    const setErrorMessage = (message: string, role: 'assistant' | 'user' = 'user') => {
+      const errorMessage: JsonApiResource<Message> = {
+        id: Date.now().toString(),
+        type: 'messages',
+        attributes: {
+          role: role,
+          content: message,
+          attachments: [],
+          createdAt: new Date(),
+        },
+      };
+      patchState(store, (state) => ({
+        messages: [...state.messages, errorMessage],
+      }));
+    };
 
     return {
       newChat,
@@ -51,25 +71,24 @@ export const ChatStore = signalStore(
             await newChat();
           } catch (error) {
             // If chat creation fails, append an error message and stop execution
-            const errorMessage: Message = {
+            setErrorMessage(
-              id: Date.now().toString(),
+              'Failed to initialize a new chat session. Please try again.',
-              role: 'ai',
+              'assistant',
-              content: 'Failed to initialize a new chat session. Please try again.',
+            );
-              timestamp: new Date(),
-            };
-            patchState(store, (state) => ({
-              messages: [...state.messages, errorMessage],
-            }));
             return;
           }
         }
 
         // Add user message
-        const userMessage: Message = {
+        const userMessage: JsonApiResource<Message> = {
           id: Date.now().toString(),
+          type: 'messages',
+          attributes: {
             role: 'user',
-          content,
+            content: content,
-          timestamp: new Date(),
+            attachments: [],
+            createdAt: new Date(),
+          },
         };
 
         patchState(store, (state) => ({
@@ -77,19 +96,12 @@ export const ChatStore = signalStore(
           isLoading: true,
         }));
         try {
-          const response = await lastValueFrom(
+          const aiMessage: MessageResponse = await lastValueFrom(
             chatService.sendMessage(<string>store.id(), content),
           );
 
-          const aiMessage: Message = {
-            id: (Date.now() + 1).toString(),
-            role: 'ai',
-            content: response.data.attributes.post,
-            timestamp: new Date(response.data.attributes.createdAt),
-          };
-
           patchState(store, (state) => ({
-            messages: [...state.messages, aiMessage],
+            messages: [...state.messages, aiMessage.data],
             isLoading: false,
           }));
         } catch (error: any) {
@@ -106,20 +118,40 @@ export const ChatStore = signalStore(
               }
             }
           }
-
+          setErrorMessage(errorText, 'assistant');
-          const errorMessage: Message = {
+          patchState(store, () => ({
-            id: (Date.now() + 1).toString(),
-            role: 'ai',
-            content: errorText,
-            timestamp: new Date(),
-          };
-
-          patchState(store, (state) => ({
-            messages: [...state.messages, errorMessage],
             isLoading: false,
           }));
         }
       },
+      fetchChatHistory: async () => {
+        if (!store.id()) {
+          setErrorMessage('Please create a new chat session first.', 'assistant');
+          return;
+        }
+        patchState(store, { isLoading: true });
+
+        try {
+          const chatHistory = await lastValueFrom(chatService.getMessages(<string>store.id()));
+          patchState(store, { messages: chatHistory.data, isLoading: false });
+        } catch (error: any) {
+          let errorText = 'Failed to load chat history. Please try again.';
+
+          if (error instanceof HttpErrorResponse && error.status === 422) {
+            errorText = error.error?.message || 'Validation error.';
+
+            if (error.error?.errors) {
+              const firstErrorKey = Object.keys(error.error.errors)[0];
+              if (firstErrorKey && error.error.errors[firstErrorKey].length > 0) {
+                errorText = error.error.errors[firstErrorKey][0];
+              }
+            }
+          }
+
+          setErrorMessage(errorText, 'assistant');
+          patchState(store, { isLoading: false });
+        }
+      },
     };
   }),
 );

frontend/src/app/chat/chat.ts

@@ -38,6 +38,7 @@ export class Chat {
       if (urlId) {
         // If an ID exists in the URL, populate it in the store
         this.chatStore.setChatId(urlId);
+        this.chatStore.fetchChatHistory();
       }
     });
   }

frontend/src/app/chat/chat.types.ts

@@ -1,4 +1,4 @@
-import { JsonApiDocument, JsonApiResource } from '../core/types/api';
+import { JsonApiCollection, JsonApiDocument, JsonApiResource } from '../core/types/api';
 
 export interface NewChatAttributes {
   id: string;
@@ -9,22 +9,18 @@ export interface NewChatAttributes {
 
 export type NewChatResponse = JsonApiDocument<NewChatAttributes>;
 
-export interface MessageAttributes {
+export interface Message {
-  post: string;
+  role: 'assistant' | 'user';
-  image: string;
-  createdAt: string;
-}
-export type MessageResponse = JsonApiDocument<MessageAttributes>;
-
-export type Message = {
-  id: string;
-  role: 'user' | 'ai';
   content: string;
-  timestamp: Date;
+  attachments: string[] | null;
-};
+  createdAt: Date;
+}
+
+export type MessageResponse = JsonApiDocument<Message>;
+export type MessageCollection = JsonApiCollection<Message>;
 
 export type ChatState = {
-  messages: Message[];
+  messages: JsonApiResource<Message>[];
   isLoading: boolean;
   id: string | null;
 };

frontend/src/app/core/types/api.ts

@@ -7,3 +7,30 @@ export interface JsonApiResource<T> {
 export interface JsonApiDocument<T> {
   data: JsonApiResource<T>;
 }
+
+export interface MetaLinks {
+  url: string | null;
+  label: string;
+  page: number | null;
+  active: boolean;
+}
+
+export interface JsonApiCollection<T> {
+  data: JsonApiResource<T>[];
+  links: {
+    first: string;
+    last: string;
+    prev: string | null;
+    next: string | null;
+  };
+  meta: {
+    current_page: number;
+    from: number;
+    last_page: number;
+    links: MetaLinks[];
+    path: string;
+    per_page: number;
+    to: number;
+    total: number;
+  };
+}