package serverSonfig

import (
	"encoding/json"
	"fmt"
	"os"

	"doll/internal/log"

	hjson "github.com/hjson/hjson-go/v4"
)

// MyConfig config structure prototype.
type MyConfig struct {
	Loglevel string `json:"loglevel,omitempty"`
	Logfile  string `json:"logfile,omitempty"`
}

var (
	// Config contains application running config data.
	Config MyConfig
)

// ReadConfig reads and validates config file. Setups defaults where possible if values are not provided.
func ReadConfig(location string) error { //nolint:gocognit,gocyclo
	var (
		err          error
		configLoaded bool
	)

	fileInfo, err := os.Stat(location)

	if err != nil {
		return fmt.Errorf("unable to read %s: %w", location, err)
	}

	// Config file seems to be too long for valid config.
	if fileInfo.Size() > 65535 {
		return fmt.Errorf("config file %s is too long for config, skipping", location)
	}

	buf, err := os.ReadFile(location)

	// Config file is unreadable for some reasons.
	if err != nil {
		return fmt.Errorf("Skip reading config file %s: %s", location, err)
	}

	// According to docs hjson claims to be able to pase bad json, but parses it to go map.
	// It is more interesting to get strict as result, so we parse data to go map, then make json out of this map and
	// then parse this json to struct. It is not the most effective and speedy solution but it works and this action
	// been performed not so often.
	var (
		sampleConfig MyConfig
		tmp          map[string]interface{}
	)

	err = hjson.Unmarshal(buf, &tmp)

	// Unable to parse json to map, that is unfortunate.
	if err != nil {
		return fmt.Errorf("Skip parsing config file %s: %s", location, err)
	}

	tmpJSON, err := json.Marshal(tmp)

	// Unable to parse map to json, well, we can nothing to with that.
	if err != nil {
		return fmt.Errorf("Skip parsing config file %s: %s", location, err)
	}

	// Unable to parse json to struct, just bail it here.
	if err := json.Unmarshal(tmpJSON, &sampleConfig); err != nil {
		return fmt.Errorf("Skip parsing config file %s: %s", location, err)
	}

	// Time to validate config values here.
	if sampleConfig.Loglevel == "" {
		sampleConfig.Loglevel = "info"

		log.Info("loglevel not defined in config, using info")
	}

	// sampleConfig.Log = "" if not set

	// TODO: validate the rest values fron config.

	Config = sampleConfig
	configLoaded = true

	log.Infof("Using %s as config file", location)

	if !configLoaded {
		return fmt.Errorf("config was not loaded!") //nolint:goerr113,revive,stylecheck
	}

	return err //nolint:wrapcheck
}

/* vim: set ft=go noet ai ts=4 sw=4 sts=4: */