package store

import (
	"context"
	"errors"
	"testing"
	"time"

	"github.com/google/uuid"
)

func TestSameSnapshotContentIgnoresOrder(t *testing.T) {
	comm := "c1"
	a := &ModulePrefixSnapshot{InputHash: "h", Prefixes: []PrefixRow{
		{Prefix: "203.0.113.0/24", CommunityID: &comm, Source: "cdn:a"},
		{Prefix: "198.51.100.0/24", Source: "cdn:b"},
	}}
	b := &ModulePrefixSnapshot{InputHash: "h", Prefixes: []PrefixRow{
		{Prefix: "198.51.100.0/24", Source: "cdn:b"},
		{Prefix: "203.0.113.0/24", CommunityID: &comm, Source: "cdn:a"},
	}}
	if !SameSnapshotContent(a, b) {
		t.Fatal("same set in another order was treated as new")
	}
	b.Prefixes[0].Prefix = "192.0.2.0/24"
	if SameSnapshotContent(a, b) {
		t.Fatal("different prefix compared equal")
	}
}

func TestPrefixSnapshotHashIgnoresOrder(t *testing.T) {
	rows := []PrefixRow{
		{Prefix: "203.0.113.0/24", Source: "ip_range"},
		{Prefix: "198.51.100.0/24", Source: "cdn:a"},
	}
	rev := []PrefixRow{rows[1], rows[0]}
	if PrefixSnapshotHash(rows) != PrefixSnapshotHash(rev) {
		t.Fatal("prefix hash depends on order")
	}
	rev = append(rev, PrefixRow{Prefix: "2001:db8::/32", Source: "ip_range"})
	if PrefixSnapshotHash(rows) == PrefixSnapshotHash(rev) {
		t.Fatal("prefix change kept the same hash")
	}
}

func TestCreateRenderRevisionReusesPrefixSnapshot(t *testing.T) {
	m := NewMemory()
	m.SeedDemo()
	tenant, _, mod, _, _ := m.DemoIDs()
	ctx := context.Background()
	rows := []PrefixRow{
		{Prefix: "203.0.113.0/24", Source: "ip_range"},
		{Prefix: "198.51.100.0/24", Source: "cdn:a"},
	}
	rev1 := uuid.NewString()
	if err := m.CreateRenderRevision(ctx, rev1, tenant, mod, nil, "hash-peer-a", map[string]string{"bird.conf": "a"}, rows); err != nil {
		t.Fatal(err)
	}
	rev2 := uuid.NewString()
	reversed := []PrefixRow{rows[1], rows[0]}
	if err := m.CreateRenderRevision(ctx, rev2, tenant, mod, nil, "hash-peer-b", map[string]string{"bird.conf": "b"}, reversed); err != nil {
		t.Fatal(err)
	}
	if m.revPrefixSnap[rev1] == "" || m.revPrefixSnap[rev1] != m.revPrefixSnap[rev2] {
		t.Fatalf("peer-only change copied prefix rows: %q vs %q", m.revPrefixSnap[rev1], m.revPrefixSnap[rev2])
	}
	if len(m.prefixSnapRows) != 1 {
		t.Fatalf("stored prefix snapshots: %d", len(m.prefixSnapRows))
	}
	page, _, _ := m.ListRevisionPrefixes(tenant, rev2, "", 10)
	if len(page) != 2 {
		t.Fatalf("reused snapshot not readable: %+v", page)
	}
	changed := append(append([]PrefixRow(nil), rows...), PrefixRow{Prefix: "2001:db8::/32", Source: "ip_range"})
	rev3 := uuid.NewString()
	if err := m.CreateRenderRevision(ctx, rev3, tenant, mod, nil, "hash-prefix", nil, changed); err != nil {
		t.Fatal(err)
	}
	if m.revPrefixSnap[rev3] == m.revPrefixSnap[rev1] || len(m.prefixSnapRows) != 2 {
		t.Fatalf("prefix change did not allocate a snapshot: id=%s count=%d", m.revPrefixSnap[rev3], len(m.prefixSnapRows))
	}
}

func TestUpdateModulePrefixSnapshotCancelledContext(t *testing.T) {
	m := NewMemory()
	m.SeedDemo()
	tenant, mod, _, _, _ := m.DemoIDs()
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	err := m.UpdateModulePrefixSnapshot(ctx, tenant, mod, func(*ModulePrefixSnapshot) (*ModulePrefixSnapshot, error) {
		t.Fatal("snapshot update ran after cancel")
		return nil, nil
	})
	if !errors.Is(err, context.Canceled) {
		t.Fatalf("err=%v", err)
	}
}

func TestMemorySnapshotLockUsesSnapshotTimeout(t *testing.T) {
	t.Setenv("EVOBGP_SNAPSHOT_TIMEOUT", "80ms")
	m := NewMemory()
	hold, err := m.lockModuleSnapshot(context.Background(), "tenant", "module")
	if err != nil {
		t.Fatal(err)
	}
	defer hold()
	start := time.Now()
	_, err = m.lockModuleSnapshot(context.Background(), "tenant", "module")
	if !errors.Is(err, context.DeadlineExceeded) {
		t.Fatalf("err=%v", err)
	}
	if time.Since(start) > time.Second {
		t.Fatalf("lock wait ignored snapshot timeout: %s", time.Since(start))
	}
}

func TestSnapshotWriteBudgetKeepsCallerDeadline(t *testing.T) {
	parent, cancel := context.WithTimeout(context.Background(), time.Hour)
	defer cancel()
	got, stop, installed := SnapshotWriteBudget(parent)
	defer stop()
	if installed {
		t.Fatal("caller deadline was replaced")
	}
	dl, ok := got.Deadline()
	if !ok || time.Until(dl) < 30*time.Minute {
		t.Fatal("caller deadline was shortened")
	}
}

func TestSetASNPrefixCacheKeepsRowsWhenSetUnchanged(t *testing.T) {
	m := NewMemory()
	if err := m.SetASNPrefixCache(64500, "holder-a", []string{"203.0.113.0/24", "198.51.100.0/24"}); err != nil {
		t.Fatal(err)
	}
	before := m.asnPrefixCache[64500]
	ptr := &before.Prefixes[0]
	fetched := before.FetchedAt
	time.Sleep(5 * time.Millisecond)
	if err := m.SetASNPrefixCache(64500, "holder-b", []string{"198.51.100.0/24", "203.0.113.0/24"}); err != nil {
		t.Fatal(err)
	}
	after := m.asnPrefixCache[64500]
	if &after.Prefixes[0] != ptr {
		t.Fatal("unchanged ASN prefixes were rewritten")
	}
	if !after.FetchedAt.After(fetched) {
		t.Fatal("fetched_at was not updated")
	}
	if after.Holder != "holder-b" {
		t.Fatalf("holder=%q", after.Holder)
	}
}