package config

import (
	"encoding/json"
	"errors"
	"fmt"
	"io/fs"
	"os"
	"strconv"

	"github.com/sirupsen/logrus"
)

type TelegramConfig struct {
	ChannelID int64  `json:"channel_id"`
	Token     string `json:"token"`
}

type LogConfig struct {
	Level logrus.Level
}

type jsonLogConfig struct {
	Level string `json:"level"`
}

type ListenerConfig struct {
	SockPath string `json:"sock_path"`
}

type Config struct {
	Telegram TelegramConfig
	Log      LogConfig
	Listener ListenerConfig
}

type jsonConfig struct {
	Telegram TelegramConfig `json:"telegram"`
	Log      jsonLogConfig  `json:"log"`
	Listener ListenerConfig `json:"listener"`
}

func parseLevel(lvlStr string) logrus.Level {
	for _, lvl := range logrus.AllLevels {
		if lvl.String() == lvlStr {
			return lvl
		}
	}
	return logrus.InfoLevel
}

var defaultConfig Config = Config{
	Telegram: TelegramConfig{
		ChannelID: 0,
		Token:     "",
	},
	Log: LogConfig{
		Level: logrus.InfoLevel,
	},
	Listener: ListenerConfig{
		SockPath: "input/notifier.sock",
	},
}

func checkOverride(conf *Config) {
	if val, ok := os.LookupEnv("LOG_LEVEL"); ok {
		conf.Log.Level = parseLevel(val)
	}
	if val, ok := os.LookupEnv("SOCK_PATH"); ok {
		conf.Listener.SockPath = val
	}
	if val, ok := os.LookupEnv("TELEGRAM_CHANNEL_ID"); ok {
		if intVal, err := strconv.Atoi(val); err == nil {
			conf.Telegram.ChannelID = int64(intVal)
		}
	}
	if val, ok := os.LookupEnv("TELEGRAM_TOKEN"); ok {
		conf.Telegram.Token = val
	}
}

func New(filepath string) (*Config, error) {
	content, err := os.ReadFile(filepath)
	if err != nil {
		if errors.Is(err, fs.ErrNotExist) {
			conf := defaultConfig
			checkOverride(&conf)
			return &conf, nil
		}
		return nil, fmt.Errorf("failed to read config file %q: %w", filepath, err)
	}
	var jsonConf jsonConfig
	if err := json.Unmarshal(content, &jsonConf); err != nil {
		return nil, fmt.Errorf("failed to parse config file: %w", err)
	}
	conf := &Config{
		Telegram: jsonConf.Telegram,
		Log: LogConfig{
			Level: parseLevel(jsonConf.Log.Level),
		},
		Listener: jsonConf.Listener,
	}
	checkOverride(conf)
	return conf, nil
}