feat: add relative time filtering (1h, 2d, 30m)

Support filtering by relative time in addition to absolute time:
- 1h: past 1 hour
- 2d: past 2 days
- 30m: past 30 minutes

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: atopos31

README.md

@@ -63,9 +63,14 @@ agent-rss fetch --all --format json
 ### Filtering
 
 ```bash
-# Filter by time range
+# Filter by relative time (past hours/days/minutes)
+agent-rss fetch --all --since 1h      # past 1 hour
+agent-rss fetch --all --since 2d      # past 2 days
+agent-rss fetch --all --since 30m     # past 30 minutes
+
+# Filter by absolute time
 agent-rss fetch --all --since 2026-03-12
-agent-rss fetch --all --since 2026-03-12T08:00:00Z --until 2026-03-12T18:00:00Z
+agent-rss fetch --all --since 2026-03-12T08:00:00+08:00 --until 2026-03-12T18:00:00+08:00
 
 # Filter by title keyword
 agent-rss fetch --all --title "AI"
@@ -74,7 +79,7 @@ agent-rss fetch --all --title "AI"
 agent-rss fetch --all --content "machine learning"
 
 # Combine filters
-agent-rss fetch --all --since 2026-03-12 --title "Go" --title "Rust"
+agent-rss fetch --all --since 1d --title "Go" --title "Rust"
 ```
 
 ### Global Options

README_CN.md

@@ -63,7 +63,12 @@ agent-rss fetch --all --format json
 ### 过滤
 
 ```bash
-# 按时间范围过滤
+# 按相对时间过滤（过去几小时/几天/几分钟）
+agent-rss fetch --all --since 1h      # 过去 1 小时
+agent-rss fetch --all --since 2d      # 过去 2 天
+agent-rss fetch --all --since 30m     # 过去 30 分钟
+
+# 按绝对时间过滤
 agent-rss fetch --all --since 2026-03-12
 agent-rss fetch --all --since 2026-03-12T08:00:00+08:00 --until 2026-03-12T18:00:00+08:00
 
@@ -74,7 +79,7 @@ agent-rss fetch --all --title "AI"
 agent-rss fetch --all --content "机器学习"
 
 # 组合过滤
-agent-rss fetch --all --since 2026-03-12 --title "Go" --title "Rust"
+agent-rss fetch --all --since 1d --title "Go" --title "Rust"
 ```
 
 ### 全局选项

internal/cli/cli.go

@@ -209,11 +209,11 @@ func fetchCmd() *cli.Command {
 			},
 			&cli.StringFlag{
 				Name:  "since",
-				Usage: "filter items published after this time (RFC3339 or YYYY-MM-DD)",
+				Usage: "filter items after this time (RFC3339, YYYY-MM-DD, or relative: 1h, 2d, 30m)",
 			},
 			&cli.StringFlag{
 				Name:  "until",
-				Usage: "filter items published before this time (RFC3339 or YYYY-MM-DD)",
+				Usage: "filter items before this time (RFC3339, YYYY-MM-DD, or relative: 1h, 2d, 30m)",
 			},
 			&cli.StringSliceFlag{
 				Name:  "title",

internal/filter/filter.go

@@ -2,6 +2,8 @@
 package filter
 
 import (
+	"regexp"
+	"strconv"
 	"strings"
 	"time"
 
@@ -60,21 +62,58 @@ func containsAny(text string, keywords []string) bool {
 	return false
 }
 
-// ParseTime attempts to parse a time string in RFC3339 or YYYY-MM-DD format.
+// ParseTime attempts to parse a time string.
+// Supported formats:
+//   - RFC3339: 2026-03-12T08:30:00Z
+//   - Date: 2026-03-12
+//   - Relative: 1h, 2d, 30m (hours, days, minutes ago)
 func ParseTime(s string) (time.Time, error) {
+	// Try RFC3339
 	if t, err := time.Parse(time.RFC3339, s); err == nil {
 		return t, nil
 	}
 
+	// Try YYYY-MM-DD
 	if t, err := time.ParseInLocation("2006-01-02", s, time.Local); err == nil {
 		return t, nil
 	}
 
+	// Try relative time (e.g., 1h, 2d, 30m)
+	if t, ok := parseRelativeTime(s); ok {
+		return t, nil
+	}
+
 	return time.Time{}, &time.ParseError{
-		Layout:     "RFC3339 or YYYY-MM-DD",
+		Layout:     "RFC3339, YYYY-MM-DD, or relative (1h, 2d, 30m)",
 		Value:      s,
 		LayoutElem: "",
 		ValueElem:  s,
 		Message:    "invalid time format",
 	}
 }
+
+var relativeTimeRegex = regexp.MustCompile(`^(\d+)(m|h|d)$`)
+
+func parseRelativeTime(s string) (time.Time, bool) {
+	matches := relativeTimeRegex.FindStringSubmatch(strings.TrimSpace(s))
+	if matches == nil {
+		return time.Time{}, false
+	}
+
+	value, _ := strconv.Atoi(matches[1])
+	unit := matches[2]
+
+	var duration time.Duration
+	switch unit {
+	case "m":
+		duration = time.Duration(value) * time.Minute
+	case "h":
+		duration = time.Duration(value) * time.Hour
+	case "d":
+		duration = time.Duration(value) * 24 * time.Hour
+	default:
+		return time.Time{}, false
+	}
+
+	return time.Now().Add(-duration), true
+}

internal/filter/filter_test.go

@@ -96,3 +96,40 @@ func TestParseTime(t *testing.T) {
 		}
 	}
 }
+
+func TestParseTime_Relative(t *testing.T) {
+	tests := []struct {
+		input    string
+		minAgo   time.Duration
+		maxAgo   time.Duration
+		wantErr  bool
+	}{
+		{"1h", 59 * time.Minute, 61 * time.Minute, false},
+		{"2h", 119 * time.Minute, 121 * time.Minute, false},
+		{"1d", 23 * time.Hour, 25 * time.Hour, false},
+		{"30m", 29 * time.Minute, 31 * time.Minute, false},
+		{"0m", 0, 1 * time.Minute, false},
+		{"abc", 0, 0, true},
+		{"1x", 0, 0, true},
+		{"h1", 0, 0, true},
+	}
+
+	for _, tt := range tests {
+		parsed, err := ParseTime(tt.input)
+		if tt.wantErr {
+			if err == nil {
+				t.Errorf("ParseTime(%q): expected error, got nil", tt.input)
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf("ParseTime(%q): unexpected error: %v", tt.input, err)
+			continue
+		}
+
+		ago := time.Since(parsed)
+		if ago < tt.minAgo || ago > tt.maxAgo {
+			t.Errorf("ParseTime(%q): got %v ago, want between %v and %v", tt.input, ago, tt.minAgo, tt.maxAgo)
+		}
+	}
+}