From f3b740c71f1fa49c0bdb524c0ee846cc756a97a5 Mon Sep 17 00:00:00 2001
From: Romulo De Lazzari <romulodelazzari@gmail.com>
Date: Fri, 13 Nov 2020 16:22:19 +0000
Subject: [PATCH] change return to array instead of int

---
 README.md         |  3 ++-
 src/Ema.php       | 12 +++++-------
 tests/TestEma.php |  2 +-
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 97056be..8911031 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,8 @@ or add `romulodl/ema` to your `composer.json`. Please check the latest version i
 
 ```php
 $ema = new Romulodl\Ema();
-$ema->calculate(array $values, int $period = 9);
+$values = $ema->calculate(array $values, int $period = 9);
+// return array, $values[0] being the last one
 ```
 
 For example:
diff --git a/src/Ema.php b/src/Ema.php
index 3774cef..2ae65c3 100644
--- a/src/Ema.php
+++ b/src/Ema.php
@@ -7,26 +7,24 @@ class Ema
 	/**
 	 * Calculate the EMA based on this formula
 	 * (Close - previous EMA) * (2 / n+1) + previous EMA
-	 *
-	 * The previous values options exists to try to smooth the current calculation
-	 * if it is empty, it will calculate the SMA for the first round.
 	 */
-	public function calculate(array $values, int $period = 9) : float
+	public function calculate(array $values, int $period = 9) : array
 	{
 		if (empty($values) || count($values) < $period) {
 			throw new \Exception('[' . __METHOD__ . '] $values parameters is empty');
 		}
 
 		$mult = 2 / ($period + 1);
-		$ema = 0;
+		$ema[] = 0;
 		foreach ($values as $value) {
 			if ( !is_numeric($value)) {
 				throw new \Exception('[' . __METHOD__ . '] invalid value: '. $value);
 			}
 
-			$ema = ($value - $ema) * $mult + $ema;
+			$prev = array_slice($ema, -1)[0];
+			$ema[] = ($value - $prev) * $mult + $prev;
 		}
 
-		return $ema;
+		return array_reverse($ema);
 	}
 }
diff --git a/tests/TestEma.php b/tests/TestEma.php
index 04a2850..821de0f 100644
--- a/tests/TestEma.php
+++ b/tests/TestEma.php
@@ -15,7 +15,7 @@ public function testCalculateWithMorePreviousValues(): void
 		}
 
 		$ema = new Ema();
-		$this->assertSame(9101.36, round($ema->calculate($values), 2));
+		$this->assertSame(9101.36, round($ema->calculate($values)[0], 2));
 	}
 
 	public function testCalculateWithEmptyArray(): void