Add facts cache

config/nushell/motd.nu.tmpl

@@ -1,4 +1,34 @@
-let fact = (try { http get https://uselessfacts.jsph.pl/api/v2/facts/random | get text } catch { "I wasn't able to provide a fact." });
-echo $"Hello (ansi purple_bold)({{#if flags.windows}}$env.USERNAME{{else}}$env.USER{{/if}})(ansi reset),
+def print-fact [] {
+  let username = {{#if flags.windows}}$env.USERNAME{{else}}$env.USER{{/if}}
+  echo $"Hello (ansi purple_bold)($username)(ansi reset),
 it's the (ansi purple_bold)(date now | format date '%d.%m.%Y')(ansi reset) at (ansi purple_bold)(date now | format date '%H:%M:%S')(ansi reset)
-Did you know: (ansi purple_bold)($fact)(ansi reset)"
+Did you know: (ansi purple_bold)(fact)(ansi reset)"
+}
+
+def fact [] {
+  let cache_file = "{{dirs.data}}/facts.txt"
+  if not ($cache_file | path exists) {
+    touch $cache_file
+  }
+  mut all_facts = open $cache_file | lines
+
+  if ($all_facts | length) < 4 {
+    try {
+      $all_facts = (fetch-facts | prepend $all_facts)
+    } catch {|e|
+      print -e $"Failed to refresh facts cache ($e)"
+    }
+  }
+  $all_facts | skip 1 | str join "\n" | save -f $cache_file
+  if ($all_facts | is-empty) {
+    "I wasn't able to provide a fact." 
+  } else {
+    $all_facts | first
+  }
+}
+
+def fetch-facts [num_facts: number = 10] {
+  0..($num_facts) | par-each { http get https://uselessfacts.jsph.pl/api/v2/facts/random | get text }
+}
+
+print-fact