From 06dcef8884bba341119e10a460611bd39408447e Mon Sep 17 00:00:00 2001
From: Michael Thomson <michael@michaelthomson.dev>
Date: Mon, 3 Jun 2024 12:48:21 -0400
Subject: [PATCH] concurrency

---
 concurrency/websitechecker.go      | 25 ++++++++++++++++
 concurrency/websitechecker_test.go | 47 ++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 concurrency/websitechecker.go
 create mode 100644 concurrency/websitechecker_test.go

diff --git a/concurrency/websitechecker.go b/concurrency/websitechecker.go
new file mode 100644
index 0000000..495fa3b
--- /dev/null
+++ b/concurrency/websitechecker.go
@@ -0,0 +1,25 @@
+package concurrency
+
+type WebsiteChecker func(string) bool
+type result struct {
+  string
+  bool
+}
+
+func CheckWebsites(wc WebsiteChecker, urls []string) map[string]bool {
+  results := make(map[string]bool)
+  resultChannel := make(chan result)
+
+  for _, url := range urls {
+    go func(u string) {
+      resultChannel <- result{u, wc(u)}
+    }(url)
+  }
+
+  for i := 0; i < len(urls); i++ {
+    r := <-resultChannel
+    results[r.string] = r.bool
+  }
+
+  return results
+}
diff --git a/concurrency/websitechecker_test.go b/concurrency/websitechecker_test.go
new file mode 100644
index 0000000..83fa69d
--- /dev/null
+++ b/concurrency/websitechecker_test.go
@@ -0,0 +1,47 @@
+package concurrency
+
+import (
+	"reflect"
+	"testing"
+	"time"
+)
+
+func mockWebsiteChecker(url string) bool {
+	return url != "waat://furhurterwe.geds"
+}
+
+func TestCheckWebsites(t *testing.T) {
+  websites := []string{
+    "http://google.com",
+    "http://blog.gypsydave5.com",
+    "waat://furhurterwe.geds",
+  }
+
+  want := map[string]bool{
+		"http://google.com":          true,
+		"http://blog.gypsydave5.com": true,
+		"waat://furhurterwe.geds":    false,
+	}
+
+  got := CheckWebsites(mockWebsiteChecker, websites)
+
+  if !reflect.DeepEqual(want, got) {
+    t.Fatalf("wanted %v, got %v", got, want) 
+  }
+}
+
+func slowStubWesiteChecker(_ string) bool {
+  time.Sleep(20 * time.Millisecond)
+  return true
+}
+
+func BenchmarkCheckWebsites(b *testing.B) {
+  urls := make([]string, 100)
+  for i := 0; i < len(urls); i++ {
+    urls[i] = "a url"
+  }
+  b.ResetTimer()
+  for i := 0; i < b.N; i++ {
+    CheckWebsites(slowStubWesiteChecker, urls)
+  }
+}