package storage

import (
	"strings"
	"testing"
	"time"

	"hamlab/internal/cron"
)

func TestSnapTimeReadsZfSnapNames(t *testing.T) {
	// the real thing off grid
	taken, exp, ok := SnapTime("tank@2026-09-24_02.30.01--6w")
	if !ok {
		t.Fatal("zfSnap's own name must parse")
	}
	if taken.Format("2006-01-02 15:04:05") != "2026-09-24 02:30:01" {
		t.Fatalf("taken = %v", taken)
	}
	if got := exp.Sub(taken); got != 6*7*24*time.Hour {
		t.Fatalf("ttl = %v, want 6w", got)
	}
	// a labelled one from a policy with a prefix
	if _, e, ok := SnapTime("tank/apps@nightly-2026-09-24_02.30.01--30d"); !ok || e.IsZero() {
		t.Fatal("a prefixed name must parse and expire")
	}
	// no TTL: never expires
	if _, e, ok := SnapTime("tank@2026-09-24_02.30.01"); !ok || !e.IsZero() {
		t.Fatal("a name without a TTL must parse and never expire")
	}
	// things that are not ours
	for _, n := range []string{"tank@before-upgrade", "tank@manual", "tank", "tank@2026-13-45_99.99.99--6w"} {
		if _, _, ok := SnapTime(n); ok {
			t.Errorf("%q must not parse as a scheduled snapshot", n)
		}
	}
}

func TestCronExprAndNextRun(t *testing.T) {
	now := time.Date(2026, 9, 24, 9, 15, 0, 0, time.Local)
	for _, c := range []struct {
		p    Policy
		want string
	}{
		{Policy{Every: "daily", At: "02:30"}, "30 2 * * *"},
		{Policy{Every: "hourly", At: "00:30"}, "30 * * * *"},
		{Policy{Every: "weekly", At: "04:00", Weekday: 0}, "0 4 * * 0"},
		{Policy{Every: "monthly", At: "05:15", Day: 12}, "15 5 12 * *"},
		{Policy{Every: "custom", Cron: "*/15  9-17 * * 1-5"}, "*/15 9-17 * * 1-5"},
	} {
		got, err := c.p.CronExpr()
		if err != nil || got != c.want {
			t.Errorf("CronExpr(%+v) = %q, %v; want %q", c.p.Every, got, err, c.want)
		}
	}
	// the next run is read with the same evaluator the Jobs tab uses
	daily := Policy{Every: "daily", At: "02:30"}
	if n := daily.NextRun(now); n.Hour() != 2 || n.Minute() != 30 || n.Day() != 25 {
		t.Fatalf("NextRun = %v, want 25th 02:30", n)
	}
	// a custom expression that does not parse is refused, not silently ignored
	if _, err := (&Policy{Every: "custom", Cron: "not a schedule"}).CronExpr(); err == nil {
		t.Fatal("a bad cron expression must be refused")
	}
	if _, err := (&Policy{Every: "custom", Cron: "@reboot"}).CronExpr(); err == nil {
		t.Fatal("@reboot is not a snapshot schedule")
	}
}

func TestCronFileText(t *testing.T) {
	ps := []Policy{
		{ID: "abc", Name: "tank nightly", Dataset: "tank", Every: "daily", At: "02:30", KeepFor: "6w", Enabled: true},
		{ID: "def", Name: "paused one", Dataset: "tank/apps", Every: "hourly", At: "00:05", KeepFor: "2d"},
	}
	text, err := CronFileText(ps, "core", "/usr/local/bin/hamlab", "/home/core/apps/hamlab/config.json")
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(text, "30 2 * * * core /usr/local/bin/hamlab -config /home/core/apps/hamlab/config.json zfs-snapshot abc") {
		t.Fatalf("the enabled schedule is missing or malformed:\n%s", text)
	}
	if strings.Contains(text, "zfs-snapshot def") {
		t.Fatalf("a paused schedule must not be scheduled:\n%s", text)
	}
	// every line cron will read must parse as a schedule
	for _, line := range strings.Split(text, "\n") {
		line = strings.TrimSpace(line)
		if line == "" || strings.HasPrefix(line, "#") || strings.Contains(line, "=") {
			continue
		}
		f := strings.Fields(line)
		if err := cron.ValidSchedule(strings.Join(f[:5], " ")); err != nil {
			t.Errorf("line %q: %v", line, err)
		}
	}
}

func TestValidateRefusesNonsense(t *testing.T) {
	ok := Policy{Dataset: "tank/apps", Every: "daily", At: "02:30", KeepFor: "6w"}
	if err := ok.Validate(); err != nil {
		t.Fatalf("a sane policy: %v", err)
	}
	bad := []Policy{
		{Dataset: "", Every: "daily", At: "02:30", KeepFor: "6w"},
		{Dataset: "tank", Every: "yearly", At: "02:30", KeepFor: "6w"},
		{Dataset: "tank", Every: "custom", KeepFor: "6w"},
		{Dataset: "tank", Every: "custom", Cron: "not a schedule", KeepFor: "6w"},
		{Dataset: "tank", Every: "daily", At: "25:00", KeepFor: "6w"},
		{Dataset: "tank", Every: "daily", At: "02:30"},                          // no retention
		{Dataset: "tank", Every: "daily", At: "02:30", KeepFor: "6 weeks"},      // unparseable
		{Dataset: "tank", Every: "monthly", At: "02:30", Day: 31, KeepFor: "6w"}, // not every month has one
		{Dataset: "tank", Every: "daily", At: "02:30", KeepFor: "6w", Prefix: "a--b"},
	}
	for i, p := range bad {
		if err := p.Validate(); err == nil {
			t.Errorf("bad policy %d was accepted: %+v", i, p)
		}
	}
}

func TestParseAge(t *testing.T) {
	for s, want := range map[string]time.Duration{
		"6w": 6 * 7 * 24 * time.Hour, "30d": 30 * 24 * time.Hour,
		"12h": 12 * time.Hour, "90m": 90 * time.Minute,
	} {
		if got, err := ParseAge(s); err != nil || got != want {
			t.Errorf("ParseAge(%q) = %v, %v; want %v", s, got, err, want)
		}
	}
	for _, s := range []string{"", "6", "w", "-1d", "0w", "6y", "six weeks"} {
		if _, err := ParseAge(s); err == nil {
			t.Errorf("ParseAge(%q) should fail", s)
		}
	}
}