package main

import (
	"net"
	"strconv"

	"git.gensokyo.cafe/kkyy/tgbot_misaka_5882f7/utils"
	"github.com/go-errors/errors"
	"github.com/ilyakaznacheev/cleanenv"
)

type ConfigDef struct {
	LogLevel           string  `env:"TG_LOG_LEVEL" env-default:"info"`
	AdminUIDs          []int64 `env:"TG_ADMIN_UIDS"`
	TGBotToken         string  `env:"TG_TOKEN" env-required:""`
	TGAnnounceCommands bool    `env:"TG_ANNOUNCE_CMDS"`

	// API
	APIMasterKey string `env:"TG_API_MASTER_KEY" env-required:""`
	APIListen    string `env:"TG_API_LISTEN" env-default:"127.0.0.1:8080"`

	// Traffic usage
	WatchedInterface       string `env:"TG_WATCHED_INTERFACE"`
	MonthlyTrafficLimitGiB int    `env:"TG_MONTHLY_TRAFFIC_LIMIT_GIB" env-default:"1000"`

	// AI
	OpenAIApiKey string `env:"TG_OPENAI_API_KEY"`

	// Parsed fields
	adminUidLookup map[int64]struct{}
	apiListenAddr  net.Addr
}

func (c *ConfigDef) Parse() error {
	c.adminUidLookup = make(map[int64]struct{}, len(c.AdminUIDs))
	for _, u := range c.AdminUIDs {
		if u <= 0 {
			return errors.New("invalid admin UID: " + strconv.FormatInt(u, 10))
		}
		c.adminUidLookup[u] = struct{}{}
	}

	// validate API listen
	ip, port, err := net.SplitHostPort(c.APIListen)
	if err != nil {
		return errors.WrapPrefix(err, "invalid API listen address", 0)
	}
	if tIP := net.ParseIP(ip); tIP == nil {
		return errors.New("invalid API listen address: " + ip)
	}
	if tPort, err := strconv.Atoi(port); err != nil || tPort <= 0 || tPort > 65535 {
		return errors.New("invalid API listen port: " + port)
	}

	if c.WatchedInterface == "" {
		tIf, err := utils.FindDefaultAdapter()
		if err != nil {
			return errors.WrapPrefix(err, "Watched interface is not defined and failed to find a default one.", 0)
		}
		c.WatchedInterface = tIf.Name
		logger.Infof("Watching default interface %s", c.WatchedInterface)
	}

	return nil
}

func (c *ConfigDef) IsAdmin(id int64) bool {
	_, ok := c.adminUidLookup[id]
	return ok
}

func (c *ConfigDef) GetAPIListenAddr() net.Addr {
	return c.apiListenAddr
}

func configFromEnv() (*ConfigDef, error) {
	cfg := ConfigDef{}
	err := cleanenv.ReadEnv(&cfg)
	if err != nil {
		return nil, errors.Wrap(err, 0)
	}
	return &cfg, nil
}

var config *ConfigDef

func LoadCfg() error {
	cfg, err := configFromEnv()
	if err != nil {
		return errors.WrapPrefix(err, "failed to load config from environment", 0)
	}
	if err = cfg.Parse(); err != nil {
		return errors.WrapPrefix(err, "failed to parse config", 0)
	}

	config = cfg
	return nil
}