package cli //nolint:testpackage // shares the fixtures and capture helpers

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"
	"testing"

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

const (
	// errorLinePrefix starts the final line that reports a failed command.
	errorLinePrefix = "ERROR: "

	flagVerbose = "--verbose"
	cmdRestore  = "restore"

	// blobsDir is the directory of a destination store that holds the
	// blobs.
	blobsDir = "blobs"
)

// TestEntryFailureIsPrintedOnce runs commands that fail after startup
// against a destination they cannot use. `info` is not among them: it
// cannot fail after startup.
//
//nolint:paralleltest // replaces os.Args, os.Stdout, os.Stderr and the xdg globals
func TestEntryFailureIsPrintedOnce(t *testing.T) {
	for _, command := range [][]string{
		{cmdSnapshot, cmdCreate},
		{cmdSnapshot, cmdRemove, someSnapshotID},
		{cmdSnapshot, cmdVerify, someSnapshotID},
		{cmdRemote, cmdInfo},
		{cmdPrune, flagJSON},
	} {
		for _, verbose := range []bool{false, true} {
			name := fmt.Sprintf("%s verbose=%t", strings.Join(command, " "), verbose)

			t.Run(name, func(t *testing.T) {
				requireErrorPrintedOnce(t, verbose, append([]string{flagConfig,
					writeUnusableDestinationConfig(t)}, command...)...)
			})
		}
	}
}

// TestEntryBlobUploadFailureIsPrintedOnce backs up to a destination
// whose blobs directory is a file, so the blob upload fails.
//
//nolint:paralleltest // replaces os.Args, os.Stdout, os.Stderr and the xdg globals
func TestEntryBlobUploadFailureIsPrintedOnce(t *testing.T) {
	for _, verbose := range []bool{false, true} {
		t.Run(fmt.Sprintf("verbose=%t", verbose), func(t *testing.T) {
			configPath, storeDir := writeBackupConfig(t)

			require.NoError(t, os.WriteFile(
				filepath.Join(storeDir, blobsDir), nil, 0o600))

			requireErrorPrintedOnce(t, verbose,
				flagConfig, configPath, cmdSnapshot, cmdCreate)
		})
	}
}

// TestEntryBlobDownloadFailureIsPrintedOnce backs up, deletes the blobs
// from the destination, and restores, so the blob download fails.
//
//nolint:paralleltest // replaces os.Args, os.Stdout, os.Stderr and the xdg globals
func TestEntryBlobDownloadFailureIsPrintedOnce(t *testing.T) {
	for _, verbose := range []bool{false, true} {
		t.Run(fmt.Sprintf("verbose=%t", verbose), func(t *testing.T) {
			configPath, storeDir := writeBackupConfigWithPrivateKey(t)

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

			require.NoError(t, os.RemoveAll(filepath.Join(storeDir, blobsDir)))

			requireErrorPrintedOnce(t, verbose, flagConfig, configPath,
				cmdSnapshot, cmdRestore, onlySnapshotID(t, configPath), t.TempDir())
		})
	}
}

// requireErrorPrintedOnce runs Entry with args, adding --verbose when
// verbose is set. The command must fail, and stderr must carry its error
// once, as the final ERROR: line. A log record carrying the same error
// appears only under --verbose.
func requireErrorPrintedOnce(t *testing.T, verbose bool, args ...string) {
	t.Helper()

	if verbose {
		args = append(args, flagVerbose)
	}

	code, _, stderr := runEntry(t, args...)
	require.Equal(t, 1, code)

	errorLine, records := failureOutput(t, stderr)

	if !verbose {
		assert.Zero(t, records,
			"without --verbose no log record repeats the error:\n%s", stderr)

		return
	}

	assert.NotZero(t, records,
		"--verbose must keep the log record of %q", errorLine)
}

// failureOutput requires stderr to hold exactly one ERROR: line and
// returns it, with the number of log records whose error attribute is
// the error that line reports. stderr is a pipe here, so every log
// record is a JSON object on its own line.
func failureOutput(t *testing.T, stderr string) (string, int) {
	t.Helper()

	var (
		errorLines []string
		records    []map[string]any
	)

	for line := range strings.Lines(stderr) {
		var record map[string]any
		if json.Unmarshal([]byte(line), &record) == nil {
			records = append(records, record)

			continue
		}

		if strings.Contains(line, errorLinePrefix) {
			errorLines = append(errorLines, strings.TrimSpace(line))
		}
	}

	require.Len(t, errorLines, 1,
		"the error must be printed once as an ERROR: line:\n%s", stderr)

	// An error can run over several lines; the ERROR: line holds the
	// first of them.
	repeats := 0

	for _, record := range records {
		failure, ok := record["error"].(string)
		firstLine, _, _ := strings.Cut(failure, "\n")

		if ok && strings.Contains(errorLines[0], firstLine) {
			repeats++
		}
	}

	return errorLines[0], repeats
}

// writeBackupConfigWithPrivateKey builds what writeBackupConfig builds,
// with a generated key pair in place of its recipient. The config also
// holds the private key, so that restore can decrypt the backup. Returns
// the config path and the store directory.
func writeBackupConfigWithPrivateKey(t *testing.T) (string, string) {
	t.Helper()

	configPath, storeDir := writeBackupConfig(t)

	identity, err := age.GenerateX25519Identity()
	require.NoError(t, err)

	out := ui.NewWithColor(io.Discard, false)

	require.NoError(t, writeConfigSet(out, configPath,
		"age_recipients.0", identity.Recipient().String()))
	require.NoError(t, writeConfigSet(out, configPath,
		"age_secret_key", identity.String()))

	return configPath, storeDir
}

// onlySnapshotID returns the ID of the one snapshot in the local index
// that writeBackupConfig puts beside the config file.
func onlySnapshotID(t *testing.T, configPath string) string {
	t.Helper()

	ctx := context.Background()

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

	defer func() { require.NoError(t, db.Close()) }()

	backedUp, err := database.NewRepositories(db).Snapshots.GetOnlySnapshot(ctx)
	require.NoError(t, err)

	return backedUp.ID.String()
}