feat: API for content

app/Http/Controllers/Api/TerminalApiController.php

@@ -3,9 +3,11 @@
 namespace App\Http\Controllers\Api;
 
 use App\Http\Controllers\Controller;
+use App\Models\Document;
 use App\Models\Guide;
 use App\Models\GuidePage;
 use App\Models\GuidePageEdge;
+use App\Models\KnowledgeBase;
 use App\Services\KnowledgeContextService;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
@@ -168,6 +170,66 @@ class TerminalApiController extends Controller
         });
     }
 
+    /**
+     * GET /api/terminal/documents/{document}/content
+     * 读取文档全文或指定行号区间
+     */
+    public function documentContent(Request $request, int $documentId): JsonResponse
+    {
+        $request->validate([
+            'start_line' => 'sometimes|integer|min:1',
+            'end_line' => 'sometimes|integer|min:1',
+        ]);
+
+        $terminal = $request->attributes->get('terminal');
+
+        // Find document and verify access through station → knowledge_base
+        $accessibleKbIds = KnowledgeBase::where(function ($q) use ($terminal) {
+            $q->whereDoesntHave('stations'); // global knowledge bases
+            if ($terminal->station_id) {
+                $q->orWhereHas('stations', fn ($sq) => $sq->where('stations.id', $terminal->station_id));
+            }
+        })->where('status', 'active')->pluck('id');
+
+        $document = Document::where('id', $documentId)
+            ->whereIn('knowledge_base_id', $accessibleKbIds)
+            ->where('conversion_status', 'completed')
+            ->first();
+
+        if (!$document) {
+            return response()->json(['error' => 'Document not found'], 404);
+        }
+
+        $content = $document->getMarkdownContent();
+        if ($content === null) {
+            return response()->json(['error' => 'Document content unavailable'], 404);
+        }
+
+        $lines = explode("\n", $content);
+        $totalLines = count($lines);
+
+        $startLine = $request->integer('start_line', 1);
+        $endLine = $request->integer('end_line', min($startLine + 49, $totalLines));
+        $endLine = min($endLine, $totalLines);
+
+        if ($startLine > $totalLines) {
+            return response()->json([
+                'error' => "start_line ({$startLine}) exceeds total lines ({$totalLines})",
+            ], 422);
+        }
+
+        $slice = array_slice($lines, $startLine - 1, $endLine - $startLine + 1);
+
+        return response()->json([
+            'id' => $document->id,
+            'title' => $document->title,
+            'total_lines' => $totalLines,
+            'start_line' => $startLine,
+            'end_line' => $endLine,
+            'content' => implode("\n", $slice),
+        ]);
+    }
+
     /**
      * POST /api/terminal/heartbeat
      * 终端心跳上报