From c62ed15d7357bfe5d6a592087b107c5c95a9aa56 Mon Sep 17 00:00:00 2001
From: Klondike Dragon <klondikedragon@gmail.com>
Date: Tue, 12 Dec 2023 17:42:09 -0700
Subject: [PATCH] Support PMDT and AMT time zones

Also disallow PM and AM from being specified twice in the string.

Fixes https://github.com/araddon/dateparse/issues/149
---
 parseany.go      | 28 +++++++++++++++++++++-------
 parseany_test.go | 30 ++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/parseany.go b/parseany.go
index 52f5e1a..1dc0443 100644
--- a/parseany.go
+++ b/parseany.go
@@ -114,7 +114,6 @@ const (
 	timeOffset
 	timeOffsetColon
 	timeOffsetColonAlpha
-	timeAlpha
 	timePeriod
 	timePeriodAMPM
 	timeZ
@@ -1350,17 +1349,22 @@ iterRunes:
 					} else {
 						// Could be AM/PM
 						isLower := r == 'a' || r == 'p'
+						isTwoLetterWord := ((i+2) == len(p.datestr) || p.nextIs(i+1, ' '))
 						switch {
-						case isLower && p.nextIs(i, 'm'):
+						case isLower && p.nextIs(i, 'm') && isTwoLetterWord && !p.parsedAMPM:
 							p.coalesceTime(i)
 							p.set(i, "pm")
+							p.parsedAMPM = true
 							// skip 'm'
 							i++
-						case !isLower && p.nextIs(i, 'M'):
+						case !isLower && p.nextIs(i, 'M') && isTwoLetterWord && !p.parsedAMPM:
 							p.coalesceTime(i)
 							p.set(i, "PM")
+							p.parsedAMPM = true
 							// skip 'M'
 							i++
+						default:
+							return p, unexpectedTail(p.datestr[i:])
 						}
 					}
 				case ' ':
@@ -1526,8 +1530,11 @@ iterRunes:
 				//   timeWsAlpha
 				//     00:12:00 PST
 				//     15:44:11 UTC+0100 2015
-				if r == 'm' || r == 'M' {
-					//return parse("2006-01-02 03:04:05 PM", p.datestr, loc)
+				isTwoLetterWord := ((i+1) == len(p.datestr) || p.nextIs(i, ' '))
+				if (r == 'm' || r == 'M') && isTwoLetterWord {
+					if p.parsedAMPM {
+						return p, unexpectedTail(p.datestr[i:])
+					}
 					// This isn't a time zone after all...
 					p.tzi = 0
 					p.stateTime = timeWsAMPM
@@ -1536,6 +1543,7 @@ iterRunes:
 					} else {
 						p.set(i-1, "PM")
 					}
+					p.parsedAMPM = true
 					if p.hourlen == 2 {
 						p.set(p.houri, "03")
 					} else if p.hourlen == 1 {
@@ -1668,21 +1676,26 @@ iterRunes:
 				case 'a', 'A', 'p', 'P':
 					// Could be AM/PM
 					isLower := r == 'a' || r == 'p'
+					isTwoLetterWord := ((i+2) == len(p.datestr) || p.nextIs(i+1, ' '))
 					switch {
-					case isLower && p.nextIs(i, 'm'):
+					case isLower && p.nextIs(i, 'm') && isTwoLetterWord && !p.parsedAMPM:
 						p.mslen = i - p.msi
 						p.coalesceTime(i)
 						p.set(i, "pm")
+						p.parsedAMPM = true
 						// skip 'm'
 						i++
 						p.stateTime = timePeriodAMPM
-					case !isLower && p.nextIs(i, 'M'):
+					case !isLower && p.nextIs(i, 'M') && isTwoLetterWord && !p.parsedAMPM:
 						p.mslen = i - p.msi
 						p.coalesceTime(i)
 						p.set(i, "PM")
+						p.parsedAMPM = true
 						// skip 'M'
 						i++
 						p.stateTime = timePeriodAMPM
+					default:
+						return p, unexpectedTail(p.datestr[i:])
 					}
 				default:
 					if !unicode.IsDigit(r) {
@@ -2053,6 +2066,7 @@ type parser struct {
 	formatSetLen               int
 	datestr                    string
 	fullMonth                  string
+	parsedAMPM                 bool
 	skip                       int
 	extra                      int
 	part1Len                   int
diff --git a/parseany_test.go b/parseany_test.go
index c45a5ee..1a6398f 100644
--- a/parseany_test.go
+++ b/parseany_test.go
@@ -373,6 +373,19 @@ var testInputs = []dateTest{
 	{in: "1 October 2022 23:59", out: "2022-10-01 23:59:00 +0000 UTC"},
 	{in: "1 November 2022 23:59", out: "2022-11-01 23:59:00 +0000 UTC"},
 	{in: "1 December 2022 23:59", out: "2022-12-01 23:59:00 +0000 UTC"},
+	// https://github.com/araddon/dateparse/issues/149
+	{in: "2018-09-30 21:09:13 PMDT", out: "2018-09-30 21:09:13 +0000 UTC", zname: "PMDT"},
+	{in: "2018-09-30 08:09:13 PM PMDT", out: "2018-09-30 20:09:13 +0000 UTC", zname: "PMDT"},
+	{in: "2018-09-30 08:09:13pm PMDT", out: "2018-09-30 20:09:13 +0000 UTC", zname: "PMDT"},
+	{in: "2018-09-30 21:09:13.123 PMDT", out: "2018-09-30 21:09:13.123 +0000 UTC", zname: "PMDT"},
+	{in: "2018-09-30 08:09:13.123 PM PMDT", out: "2018-09-30 20:09:13.123 +0000 UTC", zname: "PMDT"},
+	{in: "2018-09-30 08:09:13.123pm PMDT", out: "2018-09-30 20:09:13.123 +0000 UTC", zname: "PMDT"},
+	{in: "2018-09-30 21:09:13 AMT", out: "2018-09-30 21:09:13 +0000 UTC", zname: "AMT"},
+	{in: "2018-09-30 08:09:13 AM AMT", out: "2018-09-30 08:09:13 +0000 UTC", zname: "AMT"},
+	{in: "2018-09-30 08:09:13am AMT", out: "2018-09-30 08:09:13 +0000 UTC", zname: "AMT"},
+	{in: "2018-09-30 21:09:13.123 AMT", out: "2018-09-30 21:09:13.123 +0000 UTC", zname: "AMT"},
+	{in: "2018-09-30 08:09:13.123 am AMT", out: "2018-09-30 08:09:13.123 +0000 UTC", zname: "AMT"},
+	{in: "2018-09-30 08:09:13.123am AMT", out: "2018-09-30 08:09:13.123 +0000 UTC", zname: "AMT"},
 	//   yyyy-mm-dd hh:mm:ss,000
 	{in: "2014-05-11 08:20:13,787", out: "2014-05-11 08:20:13.787 +0000 UTC"},
 	//   yyyy-mm-dd hh:mm:ss +0000
@@ -713,6 +726,23 @@ var testParseErrors = []dateTest{
 	{in: "Wayne, Bruce", err: true},
 	{in: "Miami, Florida", err: true},
 	{in: "Doe, John", err: true},
+	// https://github.com/araddon/dateparse/issues/149
+	{in: "2018-09-30 21:09:13PMDT", err: true},
+	{in: "2018-09-30 08:09:13pm PM", err: true},
+	{in: "2018-09-30 08:09:13 PM PM", err: true},
+	{in: "2018-09-30 08:09:13 PMDT PM", err: true},
+	{in: "2018-09-30 21:09:13.123PMDT", err: true},
+	{in: "2018-09-30 08:09:13.123PM pm", err: true},
+	{in: "2018-09-30 08:09:13.123 pm PM", err: true},
+	{in: "2018-09-30 08:09:13.123 PMDT pm", err: true},
+	{in: "2018-09-30 21:09:13AMT", err: true},
+	{in: "2018-09-30 08:09:13am AM", err: true},
+	{in: "2018-09-30 08:09:13 AM AM", err: true},
+	{in: "2018-09-30 08:09:13 AMT AM", err: true},
+	{in: "2018-09-30 21:09:13.123AMT", err: true},
+	{in: "2018-09-30 08:09:13.123AM am", err: true},
+	{in: "2018-09-30 08:09:13.123 am AM", err: true},
+	{in: "2018-09-30 08:09:13.123 AMDT am", err: true},
 }
 
 func TestParseErrors(t *testing.T) {