From aa5c8fe9c9a2408e33115292c027cba2c27dc65a Mon Sep 17 00:00:00 2001
From: Spencer Brower <brower.spencer@gmail.com>
Date: Sat, 24 Feb 2024 11:27:58 -0500
Subject: [PATCH] feat: Filterchains can now be passed inputs and outputs.

---
 ffmpeg.nu      | 24 +++++++++++++++++++-----
 ffmpeg_test.nu | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/ffmpeg.nu b/ffmpeg.nu
index e65b2a8..d17e692 100644
--- a/ffmpeg.nu
+++ b/ffmpeg.nu
@@ -36,9 +36,7 @@ export def "run" [
 def "append last" [
   items: list
 ]: list -> list {
-  let list = $in;
-
-  ($list | range 0..-2) | append [($list | default [] | last | append $items)]
+  update (($in | length) - 1) { $in | append $items }
 }
 
 export def "cmd filters append" [
@@ -97,8 +95,8 @@ def "filter to-string" []: record<input: list<string> name: string params: table
 
 # Set the input and outputs of a filter chain
 export def filterchain [
-  #input: list<string>
-  #output: list<string>
+  --input (-i): list<string>
+  --output (-o): list<string>
   filter: closure
 ] {
   let cmd = $in;
@@ -118,6 +116,22 @@ export def filterchain [
       }
     }
     | do $filter
+    | if ($input | is-empty | not $in) {
+      update filters {
+        update (($in | length) - 1) {
+          update 0.input $input
+        }
+      }
+    } else { $in }
+    | if ($output | is-empty | not $in) {
+      update filters {
+        update (($in | length) - 1) {
+          update (($in | length) - 1) {
+            update output $output
+          }
+        }
+      }
+    } else { $in }
     | update options.chain_filters $original_option
   );
 }
diff --git a/ffmpeg_test.nu b/ffmpeg_test.nu
index ff16413..c334b85 100644
--- a/ffmpeg_test.nu
+++ b/ffmpeg_test.nu
@@ -227,3 +227,35 @@ def filterchain_appends_current_filter [] {
         options: { chain_filters: false }
       };
 }
+
+#[test]
+def filterchains_can_set_inputs_and_outputs [] {
+  let got = (cmd ['INPUT'] ['OUTPUT'] | filterchain -i ['in'] -o ['out'] { fps 25 | settb '1/25' });
+
+  assert equal $got {
+    input: ['INPUT']
+    filters: [
+      [
+        {
+          input: ['in']
+          name: 'fps'
+          params: [
+            {param: 'fps' value: '25'}
+          ]
+          output: []
+        }
+        {
+          input: []
+          name: 'settb'
+          params: [
+            {param: 'expr' value: '1/25'}
+          ]
+          output: ['out']
+        }
+      ]
+    ]
+    output: ['OUTPUT']
+    args: []
+    options: { chain_filters: false }
+    }
+  }