// gomuks - A Matrix client written in Go.
// Copyright (C) 2024 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package main

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

	"github.com/rs/zerolog"
	"go.mau.fi/util/ptr"
	"go.mau.fi/util/random"
	"go.mau.fi/zeroconfig"
	"golang.org/x/crypto/bcrypt"
	"gopkg.in/yaml.v3"
)

type Config struct {
	Web     WebConfig         `yaml:"web"`
	Logging zeroconfig.Config `yaml:"logging"`
}

type WebConfig struct {
	ListenAddress string `yaml:"listen_address"`
	Username      string `yaml:"username"`
	PasswordHash  string `yaml:"password_hash"`
	TokenKey      string `yaml:"token_key"`
}

var defaultConfig = Config{
	Web: WebConfig{
		ListenAddress: "localhost:29325",
	},
	Logging: zeroconfig.Config{
		MinLevel: ptr.Ptr(zerolog.TraceLevel),
		Writers: []zeroconfig.WriterConfig{{
			Type:   zeroconfig.WriterTypeStdout,
			Format: zeroconfig.LogFormatPrettyColored,
		}},
	},
}

func (gmx *Gomuks) LoadConfig() error {
	file, err := os.Open(filepath.Join(gmx.ConfigDir, "config.yaml"))
	if err != nil && !errors.Is(err, os.ErrNotExist) {
		return err
	}
	gmx.Config = defaultConfig
	changed := false
	if file != nil {
		err = yaml.NewDecoder(file).Decode(&gmx.Config)
		if err != nil {
			return err
		}
	} else {
		changed = true
	}
	if gmx.Config.Web.TokenKey == "" {
		gmx.Config.Web.TokenKey = random.String(64)
		changed = true
	}
	if gmx.Config.Web.Username == "" || gmx.Config.Web.PasswordHash == "" {
		fmt.Println("Please create a username and password for authenticating the web app")
		fmt.Print("Username: ")
		_, err = fmt.Scanln(&gmx.Config.Web.Username)
		if err != nil {
			return fmt.Errorf("failed to read username: %w", err)
		}
		fmt.Print("Password: ")
		var passwd string
		_, err = fmt.Scanln(&passwd)
		if err != nil {
			return fmt.Errorf("failed to read password: %w", err)
		}
		hash, err := bcrypt.GenerateFromPassword([]byte(passwd), 12)
		if err != nil {
			return fmt.Errorf("failed to hash password: %w", err)
		}
		gmx.Config.Web.PasswordHash = string(hash)
		changed = true
	}
	if changed {
		err = gmx.SaveConfig()
		if err != nil {
			return fmt.Errorf("failed to save config: %w", err)
		}
	}
	return nil
}

func (gmx *Gomuks) SaveConfig() error {
	file, err := os.OpenFile(filepath.Join(gmx.ConfigDir, "config.yaml"), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0600)
	if err != nil {
		return err
	}
	return yaml.NewEncoder(file).Encode(&gmx.Config)
}