From c9877a7bcd2be3034a71779d7652656cc2a1ed75 Mon Sep 17 00:00:00 2001
From: Jon Nappi <jnappi@dyn.com>
Date: Thu, 14 Jul 2016 13:30:20 -0400
Subject: [PATCH] adding field type for performing logical time operations

---
 fields.go      |  72 +++++++++++++++++++++++++++++++
 fields_test.go | 112 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 184 insertions(+)
 create mode 100644 fields.go
 create mode 100644 fields_test.go

diff --git a/fields.go b/fields.go
new file mode 100644
index 0000000..c50a2bd
--- /dev/null
+++ b/fields.go
@@ -0,0 +1,72 @@
+package qstring
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+)
+
+// parseOperator parses a leading logical operator out of the provided string
+func parseOperator(s string) string {
+	switch s[0] {
+	case 60: // "<"
+		switch s[1] {
+		case 61: // "="
+			return "<="
+		default:
+			return "<"
+		}
+	case 62: // ">"
+		switch s[1] {
+		case 61: // "="
+			return ">="
+		default:
+			return ">"
+		}
+	default:
+		// no operator found, default to "="
+		return "="
+	}
+}
+
+// ComparativeTime is a field that can be used for specifying a query parameter
+// which includes a conditional operator and a timestamp
+type ComparativeTime struct {
+	Operator string
+	Time     time.Time
+}
+
+// NewComparativeTime returns a new ComparativeTime instance with a default
+// operator of "="
+func NewComparativeTime() *ComparativeTime {
+	return &ComparativeTime{Operator: "="}
+}
+
+// Parse is used to parse a query string into a ComparativeTime instance
+func (c *ComparativeTime) Parse(query string) error {
+	if len(query) <= 2 {
+		return errors.New("qstring: Invalid Timestamp Query")
+	}
+
+	c.Operator = parseOperator(query)
+
+	// if no operator was provided and we defaulted to an equality operator
+	if !strings.HasPrefix(query, c.Operator) {
+		query = fmt.Sprintf("=%s", query)
+	}
+
+	var err error
+	c.Time, err = time.Parse(time.RFC3339, query[len(c.Operator):])
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// String returns this ComparativeTime instance in the form of the query
+// parameter that it came in on
+func (c ComparativeTime) String() string {
+	return fmt.Sprintf("%s%s", c.Operator, c.Time.Format(time.RFC3339))
+}
diff --git a/fields_test.go b/fields_test.go
new file mode 100644
index 0000000..b97b1e8
--- /dev/null
+++ b/fields_test.go
@@ -0,0 +1,112 @@
+package qstring
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+	"testing"
+)
+
+func TestComparativeTimeParse(t *testing.T) {
+	tme := "2006-01-02T15:04:05Z"
+	testio := []struct {
+		inp       string
+		operator  string
+		errString string
+	}{
+		{inp: tme, operator: "=", errString: ""},
+		{inp: ">" + tme, operator: ">", errString: ""},
+		{inp: "<" + tme, operator: "<", errString: ""},
+		{inp: ">=" + tme, operator: ">=", errString: ""},
+		{inp: "<=" + tme, operator: "<=", errString: ""},
+		{inp: "<=" + tme, operator: "<=", errString: ""},
+		{inp: "", operator: "=", errString: "qstring: Invalid Timestamp Query"},
+		{inp: ">=", operator: "=", errString: "qstring: Invalid Timestamp Query"},
+		{inp: ">=" + "foobar", operator: ">=",
+			errString: `parsing time "foobar" as "2006-01-02T15:04:05Z07:00": cannot parse "foobar" as "2006"`},
+	}
+
+	var ct *ComparativeTime
+	var err error
+	for _, test := range testio {
+		ct = NewComparativeTime()
+		err = ct.Parse(test.inp)
+
+		if ct.Operator != test.operator {
+			t.Errorf("Expected operator %q, got %q", test.operator, ct.Operator)
+		}
+
+		if err == nil && len(test.errString) != 0 {
+			t.Errorf("Expected error %q, got nil", test.errString)
+		}
+
+		if err != nil && err.Error() != test.errString {
+			t.Errorf("Expected error %q, got %q", test.errString, err.Error())
+		}
+	}
+}
+
+func TestComparativeTimeUnmarshal(t *testing.T) {
+	type Query struct {
+		Created  ComparativeTime
+		Modified ComparativeTime
+	}
+
+	createdTS := ">2006-01-02T15:04:05Z"
+	updatedTS := "<=2016-01-02T15:04:05-07:00"
+
+	query := url.Values{
+		"created":  []string{createdTS},
+		"modified": []string{updatedTS},
+	}
+
+	params := &Query{}
+	err := Unmarshal(query, params)
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	created := params.Created.String()
+	if created != createdTS {
+		t.Errorf("Expected created ts of %s, got %s instead.", createdTS, created)
+	}
+
+	modified := params.Modified.String()
+	if modified != updatedTS {
+		t.Errorf("Expected update ts of %s, got %s instead.", updatedTS, modified)
+	}
+}
+
+func TestComparativeTimeMarshal(t *testing.T) {
+	type Query struct {
+		Created  ComparativeTime
+		Modified ComparativeTime
+	}
+
+	createdTS := ">2006-01-02T15:04:05Z"
+	created := NewComparativeTime()
+	created.Parse(createdTS)
+	updatedTS := "<=2016-01-02T15:04:05-07:00"
+	updated := NewComparativeTime()
+	updated.Parse(updatedTS)
+
+	q := &Query{*created, *updated}
+	result, err := Marshal(q)
+	if err != nil {
+		t.Fatalf("Unable to marshal comparative timestamp: %s", err.Error())
+	}
+
+	var unescaped string
+	unescaped, err = url.QueryUnescape(result)
+	if err != nil {
+		t.Fatalf("Unable to unescape query string %q: %q", result, err.Error())
+	}
+	expected := []string{"created=>2006-01-02T15:04:05Z",
+		"modified=<=2016-01-02T15:04:05-07:00"}
+	for _, ts := range expected {
+		fmt.Println(ts)
+		if !strings.Contains(unescaped, ts) {
+			t.Errorf("Expected query string %s to contain %s", unescaped, ts)
+		}
+	}
+}