From dfcf770f166073e3b6113edb36c9c01e616ee702 Mon Sep 17 00:00:00 2001
From: Leonard Boyce <leonard@verias.com>
Date: Tue, 10 Oct 2023 14:37:50 -0400
Subject: [PATCH] (feat) Erlang date() and datetime() encoders

---
 src/thoas.erl              |  4 +++-
 src/thoas_encode.erl       | 27 ++++++++++++++++++++++++++-
 test/thoas_encode_test.erl | 11 +++++++++++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/src/thoas.erl b/src/thoas.erl
index f8ad848..0077783 100644
--- a/src/thoas.erl
+++ b/src/thoas.erl
@@ -27,11 +27,13 @@
     list(json_term()) |
     #{ binary() => json_term() }.
 
--type input_term() :: 
+-type input_term() ::
     integer() |
     float() |
     binary() |
     atom() |
+    calendar:date_time() |
+    calendar:date() |
     list(input_term()) |
     list({binary() | atom(), input_term()}) |
     #{ binary() | atom() => input_term() }.
diff --git a/src/thoas_encode.erl b/src/thoas_encode.erl
index 1d48a57..f2fbbef 100644
--- a/src/thoas_encode.erl
+++ b/src/thoas_encode.erl
@@ -1727,6 +1727,32 @@ value(Value, _Escape) when is_float(Value) ->
     float(Value);
 value([{_, _} | _] = Keyword, Escape) ->
     map_naive(Keyword, Escape);
+value({Y, M, D}, Escape)
+    when is_integer(Y) andalso Y >= 0 andalso Y =< 9999 andalso
+         is_integer(M) andalso M >= 1 andalso M =< 12 andalso
+         is_integer(D) andalso D >= 1 andalso D =< 31 ->
+    DateTime = io_lib:format("~4..0b-~2..0b-~2..0b", [Y, M, D]),
+    encode_string(iolist_to_binary(DateTime), Escape);
+value({{Y, M, D}, {H, I, S}}, Escape)
+    when is_integer(Y) andalso Y >= 0 andalso Y =< 9999 andalso
+         is_integer(M) andalso M >= 1 andalso M =< 12 andalso
+         is_integer(D) andalso D >= 1 andalso D =< 31 andalso
+         is_integer(H) andalso H >= 0 andalso H =< 23 andalso
+         is_integer(I) andalso I >= 0 andalso I =< 59 andalso
+         is_integer(S) andalso S >= 0 andalso S =< 59 ->
+    Dt = io_lib:format("~4..0b-~2..0b-~2..0bT~2..0b:~2..0b:~sZ",
+                       [Y, M, D, H, I, integer_to_list(S)]),
+    encode_string(iolist_to_binary(Dt), Escape);
+value({{Y, M, D}, {H, I, S}}, Escape)
+    when is_integer(Y) andalso Y >= 0 andalso Y =< 9999 andalso
+         is_integer(M) andalso M >= 1 andalso M =< 12 andalso
+         is_integer(D) andalso D >= 1 andalso D =< 31 andalso
+         is_integer(H) andalso H >= 0 andalso H =< 23 andalso
+         is_integer(I) andalso I >= 0 andalso I =< 59 andalso
+         is_float(S) andalso S >= 0 andalso S < 60 ->
+    Dt = io_lib:format("~4..0b-~2..0b-~2..0bT~2..0b:~2..0b:~sZ",
+                       [Y, M, D, H, I, float_to_binary(S, [short])]),
+    encode_string(iolist_to_binary(Dt), Escape);
 value(Value, Escape) when is_list(Value) ->
     list(Value, Escape);
 value(Value, Escape) when is_map(Value) ->
@@ -1736,4 +1762,3 @@ value(Value, Escape) when is_map(Value) ->
         Keyword ->
             map_naive(Keyword, Escape)
     end.
-
diff --git a/test/thoas_encode_test.erl b/test/thoas_encode_test.erl
index e12c390..079eb86 100644
--- a/test/thoas_encode_test.erl
+++ b/test/thoas_encode_test.erl
@@ -118,3 +118,14 @@ encode_test_() ->
         ?_assertEqual(Expected, iolist_to_binary(encode(Input, #{})))
         || {Input, Expected} <- Cases
     ].
+
+types_test_() ->
+    Cases =[
+        {#{<<"date">> => {2023,8,7}}, <<"{\"date\":\"2023-08-07\"}">>},
+        {#{<<"datetime">> => {{2023,8,7},{19,2,24}}}, <<"{\"datetime\":\"2023-08-07T19:02:24Z\"}">>},
+        {#{<<"datetime">> => {{2023,8,7},{19,2,24.65432}}}, <<"{\"datetime\":\"2023-08-07T19:02:24.65432Z\"}">>}
+    ],
+    [
+        ?_assertEqual(Expected, iolist_to_binary(encode(Input, #{})))
+        || {Input, Expected} <- Cases
+    ].