package cli //nolint:testpackage // shares runEntry and the hermetic config helpers

import (
	"context"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"sneak.berlin/go/vaultik/internal/database"
)

// Flags of `snapshot create` used to build argument vectors below.
const (
	flagPrune         = "--prune"
	flagKeepNewerThan = "--keep-newer-than"
)

// TestEntrySnapshotCreateRejectsKeepNewerThanBeforeBackup checks that a
// --keep-newer-than the post-backup prune could not use stops `snapshot
// create` before the backup: the command fails and the destination
// store stays empty. It used to be read only by the prune, after the
// snapshot was uploaded, and without --prune it was ignored.
//
//nolint:paralleltest // replaces os.Args, os.Stdout, os.Stderr and the xdg globals
func TestEntrySnapshotCreateRejectsKeepNewerThanBeforeBackup(t *testing.T) {
	for _, testCase := range []struct {
		name string
		args []string
	}{
		{
			name: "decimal in a day count",
			args: []string{flagPrune, flagKeepNewerThan, "1.5d"},
		},
		{
			name: "unknown unit",
			args: []string{flagPrune, flagKeepNewerThan, "4x"},
		},
		{
			name: "without --prune",
			args: []string{flagKeepNewerThan, "4w"},
		},
	} {
		t.Run(testCase.name, func(t *testing.T) {
			configPath, storeDir := writeBackupConfig(t)

			code, _, _ := runEntry(t, append(
				[]string{flagConfig, configPath, cmdSnapshot, cmdCreate},
				testCase.args...)...)

			assert.Equal(t, 1, code)

			stored, err := os.ReadDir(storeDir)
			require.NoError(t, err)
			assert.Empty(t, stored, "nothing may be uploaded")
		})
	}
}

// TestEntrySnapshotCreateReportsPostBackupPruneFailure makes the
// post-backup prune fail after a good backup, by planting a manifest
// that cannot be decoded, and checks that the failure is reported as the
// prune's and not as a failed snapshot creation.
//
//nolint:paralleltest // replaces os.Args, os.Stdout, os.Stderr and the xdg globals
func TestEntrySnapshotCreateReportsPostBackupPruneFailure(t *testing.T) {
	configPath, storeDir := writeBackupConfig(t)

	// A remote key is 64 lowercase hex characters. The prune reads every
	// manifest on the store and fails on one it cannot decode.
	plantedDir := filepath.Join(storeDir, "metadata", strings.Repeat("a", 64))
	require.NoError(t, os.MkdirAll(plantedDir, 0o750))
	require.NoError(t, os.WriteFile(
		filepath.Join(plantedDir, "manifest.json.zst"),
		[]byte("not a valid manifest"), 0o600))

	code, _, stderr := runEntry(t,
		flagConfig, configPath, cmdSnapshot, cmdCreate, flagPrune)

	assert.Equal(t, 1, code)
	assert.Contains(t, stderr, "Backup completed, but post-backup prune failed")
	assert.NotContains(t, stderr, "Snapshot creation failed")

	snapshots, err := os.ReadDir(filepath.Join(storeDir, "metadata"))
	require.NoError(t, err)
	assert.Len(t, snapshots, 2,
		"the new snapshot is on the store beside the planted one")
}

// TestEntrySnapshotCreatePruneExitsNonZeroWhenSourceIsEmpty backs up,
// empties the source directory, as a volume that is not mounted leaves
// its mount point, and runs `snapshot create --prune`. The command exits
// non-zero and reports the backup as completed, not as a failed snapshot
// creation. See https://git.eeqj.de/sneak/vaultik/issues/388.
//
//nolint:paralleltest // replaces os.Args, os.Stdout, os.Stderr and the xdg globals
func TestEntrySnapshotCreatePruneExitsNonZeroWhenSourceIsEmpty(t *testing.T) {
	configPath, storeDir := writeBackupConfig(t)

	code, _, _ := runEntry(t, flagConfig, configPath, cmdSnapshot, cmdCreate)
	require.Equal(t, 0, code)

	// writeBackupConfig puts the source directory beside the config file.
	require.NoError(t, os.Remove(
		filepath.Join(filepath.Dir(configPath), "source", "file.txt")))

	code, _, stderr := runEntry(t,
		flagConfig, configPath, cmdSnapshot, cmdCreate, flagPrune)

	assert.Equal(t, 1, code)
	assert.Contains(t, stderr,
		"Backup completed, but 1 source path(s) were empty")
	assert.NotContains(t, stderr, "Snapshot creation failed")

	snapshots, err := os.ReadDir(filepath.Join(storeDir, "metadata"))
	require.NoError(t, err)
	assert.Len(t, snapshots, 2, "the older snapshot is kept")
}

// TestEntrySnapshotCreatePruneExitsNonZeroWhenMountPointIsMissing backs
// up, records in the local index that this backup found the source
// directory as a mount point, and runs `snapshot create --prune`, which
// does not find it as one. The command exits non-zero, reports the
// backup as completed, not as a failed snapshot creation, and keeps the
// older snapshot. See https://git.eeqj.de/sneak/vaultik/issues/395.
//
//nolint:paralleltest // replaces os.Args, os.Stdout, os.Stderr and the xdg globals
func TestEntrySnapshotCreatePruneExitsNonZeroWhenMountPointIsMissing(
	t *testing.T,
) {
	configPath, storeDir := writeBackupConfig(t)

	code, _, _ := runEntry(t, flagConfig, configPath, cmdSnapshot, cmdCreate)
	require.Equal(t, 0, code)

	// writeBackupConfig puts the source directory and the local index
	// beside the config file.
	dir := filepath.Dir(configPath)
	ctx := context.Background()

	db, err := database.New(ctx, filepath.Join(dir, "index.sqlite"))
	require.NoError(t, err)

	repos := database.NewRepositories(db)

	backedUp, err := repos.Snapshots.GetOnlySnapshot(ctx)
	require.NoError(t, err)
	require.NoError(t, repos.Snapshots.AddMountPoint(ctx, nil,
		backedUp.ID.String(), filepath.Join(dir, "source")))
	require.NoError(t, db.Close())

	code, _, stderr := runEntry(t,
		flagConfig, configPath, cmdSnapshot, cmdCreate, flagPrune)

	assert.Equal(t, 1, code)
	assert.Contains(t, stderr, "Backup completed, but 1 mount point(s) "+
		"an earlier snapshot recorded were not found")
	assert.NotContains(t, stderr, "Snapshot creation failed")

	snapshots, err := os.ReadDir(filepath.Join(storeDir, "metadata"))
	require.NoError(t, err)
	assert.Len(t, snapshots, 2, "the older snapshot is kept")
}

// writeBackupConfig builds a hermetic config with one small file in its
// source directory and an empty destination store directory. Returns the
// config path and the store directory.
func writeBackupConfig(t *testing.T) (string, string) {
	t.Helper()

	configPath := writeHermeticPruneConfig(t, false)

	// writeHermeticPruneConfig puts the source and store directories
	// beside the config file.
	dir := filepath.Dir(configPath)
	sourceDir := filepath.Join(dir, "source")

	require.NoError(t, os.Mkdir(sourceDir, 0o750))
	require.NoError(t, os.WriteFile(
		filepath.Join(sourceDir, "file.txt"), []byte("hello"), 0o600))

	return configPath, filepath.Join(dir, "store")
}