package chatpb

// functions to import and export the protobuf
// data to and from config files

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"time"

	"go.wit.com/lib/protobuf/bugpb"
	"go.wit.com/log"
)

// write to ~/.config/regex/ unless ENV{REGEX_HOME} is set
func (all *Chats) ConfigSave() error {
	if os.Getenv("REGEX_HOME") == "" {
		homeDir, _ := os.UserHomeDir()
		fullpath := filepath.Join(homeDir, ".config/regex")
		os.Setenv("REGEX_HOME", fullpath)
	}
	if all == nil {
		log.Warn("chatpb all == nil")
		return errors.New("chatpb.ConfigSave() all == nil")
	}

	// --- Start of Fix ---
	// Create a new, clean Chats object to avoid marshaling a slice with nil entries.
	cleanChats := NewChats() // Assuming NewChats() initializes the struct correctly.
	cleanChats.Uuid = all.Uuid
	cleanChats.Version = all.Version

	// Loop through the original chats and append only the non-nil ones.
	for _, chat := range all.GetChats() {
		if chat != nil {
			cleanChats.Chats = append(cleanChats.Chats, chat)
		} else {
			log.Warn("Found and skipped a nil chat entry during ConfigSave")
		}
	}
	// --- End of Fix ---

	data, err := cleanChats.Marshal() // Marshal the clean object, not 'all'
	if err != nil {
		log.Info("chatpb proto.Marshal() failed len", len(data), err)
		// The tryValidate logic might be less necessary now but kept for safety.
		if err := all.tryValidate(); err != nil {
			return err
		} else {
			data, err = cleanChats.Marshal() // Retry with the clean object
			if err == nil {
				log.Info("chatpb.ConfigSave() pb.Marshal() worked after validation len", len(cleanChats.Chats), "chats")
				configWrite("regex.pb", data)
				return nil
			}
		}
		return err
	}

	// --- Backup Logic ---
	filename := filepath.Join(os.Getenv("REGEX_HOME"), "regex.pb")
	if _, err := os.Stat(filename); err == nil {
		// File exists, so back it up.
		dir := filepath.Dir(filename)
		timestamp := time.Now().Format("20060102-150405")
		backupFilename := fmt.Sprintf("regex.%s.pb", timestamp)
		backupPath := filepath.Join(dir, backupFilename)
		if err := os.Rename(filename, backupPath); err != nil {
			log.Warn("Could not backup config file:", err)
		}
	}
	// --- End Backup Logic ---

	if err := configWrite("regex.pb", data); err != nil {
		log.Infof("chatpb.ConfigSave() failed len(Chats)=%d bytes=%d", len(cleanChats.Chats), len(data))
		return err
	}
	configWrite("regex.text", []byte(cleanChats.FormatTEXT()))
	// log.Infof("chatpb.ConfigSave() worked len(Chats)=%d bytes=%d", len(cleanChats.Chats), len(data))
	return nil
}

func (all *Chats) tryValidate() error {

	err := bugpb.ValidateProtoUTF8(all)
	if err != nil {
		log.Printf("Protobuf UTF-8 validation failed: %v\n", err)
	}
	if err := bugpb.SanitizeProtoUTF8(all); err != nil {
		log.Warn("Sanitation failed:", err)
		// log.Fatalf("Sanitization failed: %v", err)
		return err
	}
	return nil
}

// load the regex.pb file. I shouldn't really matter if this
// fails. the file should be autogenerated. This is used
// locally just for speed
func (all *Chats) ConfigLoad() error {
	if os.Getenv("REGEX_HOME") == "" {
		homeDir, _ := os.UserHomeDir()
		fullpath := filepath.Join(homeDir, ".config/regex")
		os.Setenv("REGEX_HOME", fullpath)
	}
	var data []byte
	var err error

	cfgname := filepath.Join(os.Getenv("REGEX_HOME"), "regex.pb")
	if data, err = loadFile(cfgname); err != nil {
		// something went wrong loading the file
		// all.sampleConfig() // causes nil panic
		return err
	}
	// this means the regex.pb file exists and was read
	if len(data) == 0 {
		// todo: add default data here since it's blank? // might cause nil panic?
		all.AddRegexComment("I like astronomy")
		log.Info(errors.New("chatpb.ConfigLoad() regex.pb is empty"))
		return nil
	}
	err = all.Unmarshal(data)
	test := NewChats()
	if test.Uuid != all.Uuid {
		log.Warn("uuids do not match", test.Uuid, all.Uuid)
		deleteProtobufFile(cfgname)
	}
	if test.Version != all.Version {
		log.Warn("versions do not match", test.Version, all.Version)
		deleteProtobufFile(cfgname)
	}
	// log.Info(cfgname, "protobuf versions and uuid match", all.Uuid, all.Version)
	return err
}

func deleteProtobufFile(filename string) {
	log.Warn("The protobuf file format has changed for", filename)
	log.Warn("Deleting old file:", filename)
	log.Warn("This file will be recreated on the next run.")
	err := os.Remove(filename)
	if err != nil {
		log.Warn("failed to remove old protobuf file", "err", err)
	}
}

func loadFile(fullname string) ([]byte, error) {
	data, err := os.ReadFile(fullname)
	if errors.Is(err, os.ErrNotExist) {
		// if file does not exist, just return nil. this
		// will cause ConfigLoad() to try the next config file like "regex.text"
		// because the user might want to edit the .config by hand
		return nil, nil
	}
	if err != nil {
		// log.Info("open config file :", err)
		return nil, err
	}
	return data, nil
}

func configWrite(filename string, data []byte) error {
	fullname := filepath.Join(os.Getenv("REGEX_HOME"), filename)

	cfgfile, err := os.OpenFile(fullname, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
	defer cfgfile.Close()
	if err != nil {
		log.Warn("open config file :", err)
		return err
	}
	if filename == "regex.text" {
		// add header
		cfgfile.Write([]byte("# this file is automatically re-generated from regex.pb, however,\n"))
		cfgfile.Write([]byte("# if you want to edit it by hand, you can:\n"))
		cfgfile.Write([]byte("# stop regex; remove regex.pb; edit regex.text; start regex\n"))
		cfgfile.Write([]byte("# this will cause the default behavior to fallback to parsing this file for the config\n"))
		cfgfile.Write([]byte("\n"))
		cfgfile.Write([]byte("# this file is intended to be used to customize settings on what\n"))
	}
	cfgfile.Write(data)
	return nil
}