Simplificacion a contabilidad clasica

api/src/Cuenta.php

@@ -28,9 +28,61 @@ class Cuenta extends Model {
     return $this->entradas;
   }
 
+  protected $cargos;
+  public function cargos() {
+    if ($this->cargos === null) {
+      $this->cargos = $this->parentOf(Transaccion::class, [Model::CHILD_KEY => 'hasta_id']);
+    }
+    return $this->cargos;
+  }
+  protected $abonos;
+  public function abonos() {
+    if ($this->abonos === null) {
+      $this->abonos = $this->parentOf(Transaccion::class, [Model::CHILD_KEY => 'desde_id']);
+    }
+    return $this->abonos;
+  }
+  protected $transacciones;
+  public function transacciones() {
+    if ($this->transacciones === null) {
+      $this->transacciones = [];
+      if ($this->abonos() !== null) {
+        $this->transacciones = array_merge($this->transacciones, $this->abonos());
+      }
+      if ($this->cargos() !== null) {
+        $this->transacciones = array_merge($this->transacciones, array_map(function($item) {
+          $item->valor = - $item->valor;
+          return $item;
+        }, $this->cargos()));
+      }
+      usort($this->transacciones, function($a, $b) {
+        $d = $a->fecha()->diffInDays($b->fecha(), false);
+        if ($d === 0) {
+          return $a->valor - $b->valor;
+        }
+        return $d;
+      });
+    }
+    return $this->transacciones;
+  }
+  protected $saldo;
+  public function saldo() {
+    if ($this->saldo === null) {
+      $this->saldo = 0;
+      if (count($this->transacciones()) > 0) {
+        $this->saldo = array_reduce($this->transacciones(), function($sum, $item) {
+          return $sum + $item->valor;
+        });
+      }
+    }
+    return $this->saldo;
+  }
+
   public function toArray(): array {
     $arr = parent::toArray();
     $arr['categoria'] = $this->categoria()->toArray();
+    $arr['saldo'] = $this->saldo();
+    $arr['saldoFormateado'] = '$' . number_format($this->saldo(), 0, ',', '.');
     return $arr;
   }
 }