search: handle date ranges in search/filter query

Handle date ranges in the filter and search commands for searching and
filtering based on the Date: header. Implement a flag (-d) that accepts
a date range <start[..end]> where the start date is included in the
range but the end date is not, i.e. [start,end).

The start or end date can be omitted: "start", "start..", "..end", or
"start..end" are all valid inputs.

An example filter query would look like this: :filter -d 2022-11-09..

The dates should be in the YYYY-MM-DD format.

Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>

3 files changed, 156 insertions, 4 deletions

diff --git a/worker/lib/daterange.go b/worker/lib/daterange.go
new file mode 100644
index 00000000..c996392c
--- /dev/null
+++ b/worker/lib/daterange.go
@@ -0,0 +1,63 @@
+package lib
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+const dateFmt = "2006-01-02"
+
+// ParseDateRange parses a date range into a start and end date. Dates are
+// expected to be in the YYYY-MM-DD format.
+//
+// Start and end dates are connected by the range operator ".." where end date
+// is not included in the date range.
+//
+// ParseDateRange can also parse open-ended ranges, i.e. start.. or ..end are
+// allowed.
+func ParseDateRange(s string) (start, end time.Time, err error) {
+	s = strings.ReplaceAll(s, " ", "")
+	i := strings.Index(s, "..")
+	switch {
+	case i < 0:
+		// single date
+		start, err = time.Parse(dateFmt, s)
+		if err != nil {
+			err = fmt.Errorf("failed to parse date: %w", err)
+			return
+		}
+		end = start.AddDate(0, 0, 1)
+
+	case i == 0:
+		// end date only
+		if len(s) < 2 {
+			err = fmt.Errorf("no date found")
+			return
+		}
+		end, err = time.Parse(dateFmt, s[2:])
+		if err != nil {
+			err = fmt.Errorf("failed to parse date: %w", err)
+			return
+		}
+
+	case i > 0:
+		// start date first
+		start, err = time.Parse(dateFmt, s[:i])
+		if err != nil {
+			err = fmt.Errorf("failed to parse date: %w", err)
+			return
+		}
+		if len(s[i:]) <= 2 {
+			return
+		}
+		// and end dates if available
+		end, err = time.Parse(dateFmt, s[(i+2):])
+		if err != nil {
+			err = fmt.Errorf("failed to parse date: %w", err)
+			return
+		}
+	}
+
+	return
+}
diff --git a/worker/lib/daterange_test.go b/worker/lib/daterange_test.go
new file mode 100644
index 00000000..983f99a0
--- /dev/null
+++ b/worker/lib/daterange_test.go
@@ -0,0 +1,55 @@
+package lib_test
+
+import (
+	"testing"
+	"time"
+
+	"git.sr.ht/~rjarry/aerc/worker/lib"
+)
+
+func TestParseDateRange(t *testing.T) {
+	dateFmt := "2006-01-02"
+	parse := func(s string) time.Time { d, _ := time.Parse(dateFmt, s); return d }
+	tests := []struct {
+		s     string
+		start time.Time
+		end   time.Time
+	}{
+		{
+			s:     "2022-11-01",
+			start: parse("2022-11-01"),
+			end:   parse("2022-11-02"),
+		},
+		{
+			s:     "2022-11-01..",
+			start: parse("2022-11-01"),
+		},
+		{
+			s:   "..2022-11-05",
+			end: parse("2022-11-05"),
+		},
+		{
+			s:     "2022-11-01..2022-11-05",
+			start: parse("2022-11-01"),
+			end:   parse("2022-11-05"),
+		},
+	}
+
+	for _, test := range tests {
+		start, end, err := lib.ParseDateRange(test.s)
+		if err != nil {
+			t.Errorf("ParseDateRange return error for %s: %v",
+				test.s, err)
+		}
+
+		if !start.Equal(test.start) {
+			t.Errorf("wrong start date; expected %v, got %v",
+				test.start, start)
+		}
+
+		if !end.Equal(test.end) {
+			t.Errorf("wrong end date; expected %v, got %v",
+				test.end, end)
+		}
+	}
+}
diff --git a/worker/lib/search.go b/worker/lib/search.go
index fe1ec114..c09feff6 100644
--- a/worker/lib/search.go
+++ b/worker/lib/search.go
@@ -4,10 +4,12 @@ import (
 	"io"
 	"net/textproto"
 	"strings"
+	"time"
 	"unicode"
 
 	"git.sr.ht/~sircmpwn/getopt"
 
+	"git.sr.ht/~rjarry/aerc/log"
 	"git.sr.ht/~rjarry/aerc/models"
 )
 
@@ -18,12 +20,14 @@ type searchCriteria struct {
 
 	WithFlags    []models.Flag
 	WithoutFlags []models.Flag
+
+	startDate, endDate time.Time
 }
 
 func GetSearchCriteria(args []string) (*searchCriteria, error) {
 	criteria := &searchCriteria{Header: make(textproto.MIMEHeader)}
 
-	opts, optind, err := getopt.Getopts(args, "rux:X:bat:H:f:c:")
+	opts, optind, err := getopt.Getopts(args, "rux:X:bat:H:f:c:d:")
 	if err != nil {
 		return nil, err
 	}
@@ -49,8 +53,18 @@ func GetSearchCriteria(args []string) (*searchCriteria, error) {
 			criteria.Header.Add("Cc", opt.Value)
 		case 'b':
 			body = true
-		case 'a':
-			text = true
+		case 'd':
+			start, end, err := ParseDateRange(opt.Value)
+			if err != nil {
+				log.Errorf("failed to parse start date: %v", err)
+				continue
+			}
+			if !start.IsZero() {
+				criteria.startDate = start
+			}
+			if !end.IsZero() {
+				criteria.endDate = end
+			}
 		}
 	}
 	switch {
@@ -116,7 +130,7 @@ func searchMessage(message RawMessage, criteria *searchCriteria,
 			return false, err
 		}
 	}
-	if parts&HEADER > 0 {
+	if parts&HEADER > 0 || parts&DATE > 0 {
 		header, err = MessageInfo(message)
 		if err != nil {
 			return false, err
@@ -188,6 +202,22 @@ func searchMessage(message RawMessage, criteria *searchCriteria,
 			}
 		}
 	}
+	if parts&DATE > 0 {
+		if date, err := header.RFC822Headers.Date(); err != nil {
+			log.Errorf("Failed to get date from header: %v", err)
+		} else {
+			if !criteria.startDate.IsZero() {
+				if date.Before(criteria.startDate) {
+					return false, nil
+				}
+			}
+			if !criteria.endDate.IsZero() {
+				if date.After(criteria.endDate) {
+					return false, nil
+				}
+			}
+		}
+	}
 	return true, nil
 }
 
@@ -227,6 +257,7 @@ const NONE MsgParts = 0
 const (
 	FLAGS MsgParts = 1 << iota
 	HEADER
+	DATE
 	BODY
 	ALL
 )
@@ -238,6 +269,9 @@ func getRequiredParts(criteria *searchCriteria) MsgParts {
 	if len(criteria.Header) > 0 {
 		required |= HEADER
 	}
+	if !criteria.startDate.IsZero() || !criteria.endDate.IsZero() {
+		required |= DATE
+	}
 	if criteria.Body != nil && len(criteria.Body) > 0 {
 		required |= BODY
 	}