From 31c19a8ef300f6be92ef9115a50b68990b14f310 Mon Sep 17 00:00:00 2001
From: Martin Lees <drov0@users.noreply.github.com>
Date: Mon, 9 Dec 2019 11:50:47 +0100
Subject: [PATCH] timestamp flag

---
 flag_timestamp.go | 130 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 flag_timestamp.go

diff --git a/flag_timestamp.go b/flag_timestamp.go
new file mode 100644
index 0000000..0b2cb23
--- /dev/null
+++ b/flag_timestamp.go
@@ -0,0 +1,130 @@
+package cli
+
+import (
+	"flag"
+	"fmt"
+	"time"
+)
+
+
+// timestamp wrap to satisfy golang's flag interface.
+type timestampWrap struct {
+	timestamp *time.Time
+	hasBeenSet bool
+	layout 	   string
+}
+
+// Set the timestamp value directly
+func (t *timestampWrap) SetTimestamp(value time.Time) {
+	if !t.hasBeenSet {
+		t.timestamp = &value
+		t.hasBeenSet = true
+	}
+}
+// Set the timestamp string layout for future parsing
+func (t *timestampWrap) SetLayout(layout string) {
+	t.layout = layout
+}
+
+// Parses the string value to timestamp
+func (t *timestampWrap) Set(value string) error {
+	timestamp, err := time.Parse(t.layout, value)
+	if err != nil {
+		return err
+	}
+
+	t.timestamp = &timestamp
+	return nil
+}
+
+// String returns a readable representation of this value (for usage defaults)
+func (t *timestampWrap) String() string {
+	return fmt.Sprintf("%#v", t.timestamp)
+}
+
+// Value returns the timestamp value stored in the flag
+func (t *timestampWrap) Value() *time.Time {
+	return t.timestamp
+}
+
+// Get returns the flag structure
+func (t *timestampWrap) Get() interface{} {
+	return *t
+}
+
+// TimestampFlag is a flag with type protobuf.timestamp
+type TimestampFlag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	FilePath    string
+	Required    bool
+	Hidden      bool
+	Layout 	    string
+	Value       timestampWrap
+	DefaultText string
+	HasBeenSet  bool
+}
+
+// IsSet returns whether or not the flag has been set through env or file
+func (f *TimestampFlag) IsSet() bool {
+	return f.HasBeenSet
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *TimestampFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *TimestampFlag) Names() []string {
+	return flagNames(f)
+}
+
+// IsRequired returns whether or not the flag is required
+func (f *TimestampFlag) IsRequired() bool {
+	return f.Required
+}
+
+// TakesValue returns true of the flag takes a value, otherwise false
+func (f *TimestampFlag) TakesValue() bool {
+	return true
+}
+
+// GetUsage returns the usage string for the flag
+func (f *TimestampFlag) GetUsage() string {
+	return f.Usage
+}
+
+// GetValue returns the flag value
+func (f *TimestampFlag) GetValue() *time.Time {
+	return f.Value.timestamp
+}
+
+// Apply populates the flag given the flag set and environment
+func (f *TimestampFlag) Apply(set *flag.FlagSet) error {
+	for _, name := range f.Names() {
+		f.Value.SetLayout(f.Layout)
+		set.Var(&f.Value, name, f.Usage)
+	}
+	return nil
+}
+
+// Timestamp gets the timestamp from a flag name
+func (c *Context) Timestamp(name string) *time.Time {
+	if fs := lookupFlagSet(name, c); fs != nil {
+		return lookupTimestamp(name, fs)
+	}
+	return nil
+}
+
+// Fetches the timestamp value from the local timestampWrap
+func lookupTimestamp(name string, set *flag.FlagSet) *time.Time {
+	f := set.Lookup(name)
+	if f != nil {
+		return (f.Value.(*timestampWrap)).Value()
+	}
+	return nil
+}