package store

import (
	"context"
	"database/sql"
	"errors"
	"path/filepath"
	"reflect"
	"strconv"
	"strings"
	"testing"
	"time"

	"banger/internal/model"
)

func TestStoreImageAndVMRoundTrip(t *testing.T) {
	t.Parallel()

	ctx := context.Background()
	store := openTestStore(t)

	image := sampleImage("image-one")
	if err := store.UpsertImage(ctx, image); err != nil {
		t.Fatalf("UpsertImage: %v", err)
	}

	vm := sampleVM("vm-one", image.ID, "172.16.0.8")
	if err := store.UpsertVM(ctx, vm); err != nil {
		t.Fatalf("UpsertVM: %v", err)
	}

	gotImage, err := store.GetImageByName(ctx, image.Name)
	if err != nil {
		t.Fatalf("GetImageByName: %v", err)
	}
	if !reflect.DeepEqual(gotImage, image) {
		t.Fatalf("GetImageByName = %+v, want %+v", gotImage, image)
	}

	gotVM, err := store.GetVM(ctx, vm.Name)
	if err != nil {
		t.Fatalf("GetVM: %v", err)
	}
	if !reflect.DeepEqual(gotVM, vm) {
		t.Fatalf("GetVM = %+v, want %+v", gotVM, vm)
	}

	images, err := store.ListImages(ctx)
	if err != nil {
		t.Fatalf("ListImages: %v", err)
	}
	if len(images) != 1 || !reflect.DeepEqual(images[0], image) {
		t.Fatalf("ListImages = %+v, want [%+v]", images, image)
	}

	vms, err := store.ListVMs(ctx)
	if err != nil {
		t.Fatalf("ListVMs: %v", err)
	}
	if len(vms) != 1 || !reflect.DeepEqual(vms[0], vm) {
		t.Fatalf("ListVMs = %+v, want [%+v]", vms, vm)
	}

	users, err := store.FindVMsUsingImage(ctx, image.ID)
	if err != nil {
		t.Fatalf("FindVMsUsingImage: %v", err)
	}
	if len(users) != 1 || users[0].ID != vm.ID {
		t.Fatalf("FindVMsUsingImage = %+v, want vm %s", users, vm.ID)
	}

	if err := store.DeleteVM(ctx, vm.ID); err != nil {
		t.Fatalf("DeleteVM: %v", err)
	}
	if _, err := store.GetVM(ctx, vm.ID); !errors.Is(err, sql.ErrNoRows) {
		t.Fatalf("GetVM after delete error = %v, want sql.ErrNoRows", err)
	}

	if err := store.DeleteImage(ctx, image.ID); err != nil {
		t.Fatalf("DeleteImage: %v", err)
	}
	if _, err := store.GetImageByID(ctx, image.ID); !errors.Is(err, sql.ErrNoRows) {
		t.Fatalf("GetImageByID after delete error = %v, want sql.ErrNoRows", err)
	}
}

func TestNextGuestIPSkipsAllocatedAddresses(t *testing.T) {
	t.Parallel()

	ctx := context.Background()
	store := openTestStore(t)
	image := sampleImage("image-next-ip")
	if err := store.UpsertImage(ctx, image); err != nil {
		t.Fatalf("UpsertImage: %v", err)
	}
	for i, ip := range []string{"172.16.0.2", "172.16.0.3", "172.16.0.5"} {
		vm := sampleVM("vm-next-"+strconv.Itoa(i), image.ID, ip)
		if err := store.UpsertVM(ctx, vm); err != nil {
			t.Fatalf("UpsertVM(%s): %v", ip, err)
		}
	}

	got, err := store.NextGuestIP(ctx, "172.16.0")
	if err != nil {
		t.Fatalf("NextGuestIP: %v", err)
	}
	if got != "172.16.0.4" {
		t.Fatalf("NextGuestIP = %q, want 172.16.0.4", got)
	}
}

func TestNextGuestIPReturnsErrorWhenRangeExhausted(t *testing.T) {
	t.Parallel()

	ctx := context.Background()
	store := openTestStore(t)
	image := sampleImage("image-full")
	if err := store.UpsertImage(ctx, image); err != nil {
		t.Fatalf("UpsertImage: %v", err)
	}
	for i := 2; i < 255; i++ {
		vm := sampleVM("vm-"+strconv.Itoa(i), image.ID, "172.16.0."+strconv.Itoa(i))
		if err := store.UpsertVM(ctx, vm); err != nil {
			t.Fatalf("UpsertVM(%d): %v", i, err)
		}
	}

	_, err := store.NextGuestIP(ctx, "172.16.0")
	if err == nil || !strings.Contains(err.Error(), "no guest IPs available") {
		t.Fatalf("NextGuestIP() error = %v, want exhaustion error", err)
	}
}

func TestGetVMRejectsMalformedRuntimeJSON(t *testing.T) {
	t.Parallel()

	ctx := context.Background()
	store := openTestStore(t)
	now := fixedTime()
	_, err := store.db.ExecContext(ctx, `
		INSERT INTO vms (
			id, name, image_id, guest_ip, state, created_at, updated_at, last_touched_at,
			spec_json, runtime_json, stats_json
		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
		"vm-malformed-runtime",
		"vm-malformed-runtime",
		"image-id",
		"172.16.0.8",
		string(model.VMStateCreated),
		now.Format(time.RFC3339),
		now.Format(time.RFC3339),
		now.Format(time.RFC3339),
		`{"vcpu_count":2}`,
		`{"guest_ip":`,
		`{}`,
	)
	if err != nil {
		t.Fatalf("insert malformed vm: %v", err)
	}

	_, err = store.GetVM(ctx, "vm-malformed-runtime")
	if err == nil || !strings.Contains(err.Error(), "unexpected end of JSON input") {
		t.Fatalf("GetVM() error = %v, want runtime JSON failure", err)
	}
}

func TestGetImageRejectsMalformedTimestamp(t *testing.T) {
	t.Parallel()

	ctx := context.Background()
	store := openTestStore(t)
	_, err := store.db.ExecContext(ctx, `
		INSERT INTO images (
			id, name, managed, artifact_dir, rootfs_path, kernel_path, initrd_path,
			modules_dir, packages_path, build_size, docker, created_at, updated_at
		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
		"image-bad-time",
		"image-bad-time",
		0,
		"",
		"/rootfs.ext4",
		"/vmlinux",
		"",
		"",
		"",
		"",
		0,
		"not-a-time",
		"not-a-time",
	)
	if err != nil {
		t.Fatalf("insert malformed image: %v", err)
	}

	_, err = store.GetImageByName(ctx, "image-bad-time")
	if err == nil || !strings.Contains(err.Error(), "cannot parse") {
		t.Fatalf("GetImageByName() error = %v, want timestamp parse failure", err)
	}
}

func openTestStore(t *testing.T) *Store {
	t.Helper()
	store, err := Open(filepath.Join(t.TempDir(), "state.db"))
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	t.Cleanup(func() {
		_ = store.Close()
	})
	return store
}

func sampleImage(name string) model.Image {
	now := fixedTime()
	return model.Image{
		ID:           name + "-id",
		Name:         name,
		Managed:      true,
		ArtifactDir:  "/artifacts/" + name,
		RootfsPath:   "/images/" + name + ".ext4",
		KernelPath:   "/kernels/" + name,
		InitrdPath:   "/initrd/" + name,
		ModulesDir:   "/modules/" + name,
		PackagesPath: "/packages/" + name + ".apt",
		BuildSize:    "8G",
		Docker:       true,
		CreatedAt:    now,
		UpdatedAt:    now,
	}
}

func sampleVM(name, imageID, guestIP string) model.VMRecord {
	now := fixedTime()
	return model.VMRecord{
		ID:            name + "-id",
		Name:          name,
		ImageID:       imageID,
		State:         model.VMStateStopped,
		CreatedAt:     now,
		UpdatedAt:     now,
		LastTouchedAt: now,
		Spec: model.VMSpec{
			VCPUCount:             2,
			MemoryMiB:             1024,
			SystemOverlaySizeByte: 8 * 1024 * 1024 * 1024,
			WorkDiskSizeBytes:     8 * 1024 * 1024 * 1024,
			NATEnabled:            true,
		},
		Runtime: model.VMRuntime{
			State:         model.VMStateStopped,
			GuestIP:       guestIP,
			TapDevice:     "tap-" + name,
			APISockPath:   "/tmp/" + name + ".sock",
			LogPath:       "/tmp/" + name + ".log",
			MetricsPath:   "/tmp/" + name + ".metrics",
			DNSName:       name + ".vm",
			VMDir:         "/state/" + name,
			SystemOverlay: "/state/" + name + "/system.cow",
			WorkDiskPath:  "/state/" + name + "/root.ext4",
		},
		Stats: model.VMStats{
			CPUPercent:         1.25,
			RSSBytes:           1024,
			VSZBytes:           2048,
			SystemOverlayBytes: 4096,
			WorkDiskBytes:      8192,
			MetricsRaw:         map[string]any{"uptime": 12.0},
			CollectedAt:        now,
		},
	}
}

func fixedTime() time.Time {
	return time.Date(2026, time.March, 16, 12, 0, 0, 0, time.UTC)
}