/*
Copyright © 2025 Lewis Wynne <lew@ily.rs>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

package cmd

import (
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"strings"
	"unicode/utf8"

	"github.com/dgraph-io/badger/v4"
	"github.com/gobwas/glob"
	"github.com/spf13/cobra"
)

type dumpEntry struct {
	Key       string `json:"key"`
	Value     string `json:"value"`
	Encoding  string `json:"encoding,omitempty"`
	Secret    bool   `json:"secret,omitempty"`
	ExpiresAt *int64 `json:"expires_at,omitempty"`
}

var dumpCmd = &cobra.Command{
	Use:          "dump [STORE]",
	Short:        "Dump all key/value pairs as NDJSON",
	Aliases:      []string{"export"},
	Args:         cobra.MaximumNArgs(1),
	RunE:         dump,
	SilenceUsage: true,
}

func dump(cmd *cobra.Command, args []string) error {
	store := &Store{}
	targetDB := "@" + config.Store.DefaultStoreName
	if len(args) == 1 {
		rawArg := args[0]
		dbName, err := store.parseDB(rawArg, false)
		if err != nil {
			return fmt.Errorf("cannot dump '%s': %v", rawArg, err)
		}
		if _, err := store.FindStore(dbName); err != nil {
			var notFound errNotFound
			if errors.As(err, &notFound) {
				return fmt.Errorf("cannot dump '%s': %v", rawArg, err)
			}
			return err
		}
		targetDB = "@" + dbName
	}

	mode, err := cmd.Flags().GetString("encoding")
	if err != nil {
		return fmt.Errorf("cannot dump '%s': %v", targetDB, err)
	}
	switch mode {
	case "auto", "base64", "text":
	default:
		return fmt.Errorf("cannot dump '%s': unsupported encoding '%s'", targetDB, mode)
	}

	includeSecret, err := cmd.Flags().GetBool("secret")
	if err != nil {
		return err
	}
	globPatterns, err := cmd.Flags().GetStringSlice("glob")
	if err != nil {
		return fmt.Errorf("cannot dump '%s': %v", targetDB, err)
	}
	separators, err := parseGlobSeparators(cmd)
	if err != nil {
		return fmt.Errorf("cannot dump '%s': %v", targetDB, err)
	}
	matchers, err := compileGlobMatchers(globPatterns, separators)
	if err != nil {
		return fmt.Errorf("cannot dump '%s': %v", targetDB, err)
	}

	opts := DumpOptions{
		Encoding:      mode,
		IncludeSecret: includeSecret,
		Matchers:      matchers,
		GlobPatterns:  globPatterns,
	}
	return dumpDatabase(store, strings.TrimPrefix(targetDB, "@"), cmd.OutOrStdout(), opts)
}

func init() {
	dumpCmd.Flags().StringP("encoding", "e", "auto", "value encoding: auto, base64, or text")
	dumpCmd.Flags().Bool("secret", false, "Include entries marked as secret")
	dumpCmd.Flags().StringSliceP("glob", "g", nil, "Filter keys with glob pattern (repeatable)")
	dumpCmd.Flags().String("glob-sep", "", fmt.Sprintf("Characters treated as separators for globbing (default %q)", defaultGlobSeparatorsDisplay()))
	rootCmd.AddCommand(dumpCmd)
}

func encodeBase64(entry *dumpEntry, v []byte) {
	entry.Value = base64.StdEncoding.EncodeToString(v)
	entry.Encoding = "base64"
}

func encodeText(entry *dumpEntry, key []byte, v []byte) error {
	if !utf8.Valid(v) {
		return fmt.Errorf("key %q contains non-UTF8 data; use --encoding=auto or base64", key)
	}
	entry.Value = string(v)
	entry.Encoding = "text"
	return nil
}

// DumpOptions controls how a store is dumped to NDJSON.
type DumpOptions struct {
	Encoding      string
	IncludeSecret bool
	Matchers      []glob.Glob
	GlobPatterns  []string
}

// dumpDatabase writes entries from dbName to w as NDJSON.
func dumpDatabase(store *Store, dbName string, w io.Writer, opts DumpOptions) error {
	targetDB := "@" + dbName
	if opts.Encoding == "" {
		opts.Encoding = "auto"
	}

	var matched bool
	trans := TransactionArgs{
		key:      targetDB,
		readonly: true,
		sync:     true,
		transact: func(tx *badger.Txn, k []byte) error {
			it := tx.NewIterator(badger.DefaultIteratorOptions)
			defer it.Close()
			for it.Rewind(); it.Valid(); it.Next() {
				item := it.Item()
				key := item.KeyCopy(nil)
				if !globMatch(opts.Matchers, string(key)) {
					continue
				}
				meta := item.UserMeta()
				isSecret := meta&metaSecret != 0
				if isSecret && !opts.IncludeSecret {
					continue
				}
				expiresAt := item.ExpiresAt()
				if err := item.Value(func(v []byte) error {
					entry := dumpEntry{
						Key:    string(key),
						Secret: isSecret,
					}
					if expiresAt > 0 {
						ts := int64(expiresAt)
						entry.ExpiresAt = &ts
					}
					switch opts.Encoding {
					case "base64":
						encodeBase64(&entry, v)
					case "text":
						if err := encodeText(&entry, key, v); err != nil {
							return err
						}
					case "auto":
						if utf8.Valid(v) {
							entry.Encoding = "text"
							entry.Value = string(v)
						} else {
							encodeBase64(&entry, v)
						}
					default:
						return fmt.Errorf("unsupported encoding '%s'", opts.Encoding)
					}
					payload, err := json.Marshal(entry)
					if err != nil {
						return err
					}
					_, err = fmt.Fprintln(w, string(payload))
					if err == nil {
						matched = true
					}
					return err
				}); err != nil {
					return err
				}
			}
			return nil
		},
	}

	if err := store.Transaction(trans); err != nil {
		return err
	}

	if len(opts.Matchers) > 0 && !matched {
		return fmt.Errorf("No matches for pattern %s", formatGlobPatterns(opts.GlobPatterns))
	}
	return nil
}