package main

import (
	"flag"
	"fmt"
	"io"
	"os"

	yaml "gopkg.in/yaml.v3"
)

const (
	defaultPort         = 7099
	defaultInstanceName = "BBJ"
	defaultHost         = "127.0.0.1"
)

type Config struct {
	Admins       []string
	Port         int
	Host         string
	InstanceName string `yaml:"instance_name"`
	AllowAnon    bool
	Debug        bool
}

type iostreams struct {
	Err io.Writer
	Out io.Writer
}

type Opts struct {
	ConfigPath string
	IO         iostreams
}

func main() {
	var configFlag = flag.String("config", "config.yml", "A path to a config file.")
	flag.Parse()
	opts := Opts{
		ConfigPath: *configFlag,
		IO: iostreams{
			Err: os.Stderr,
			Out: os.Stdout,
		},
	}

	err := _main(opts)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed: %s", err)
	}
}

func _main(opts Opts) error {
	cfg, err := parseConfig(opts.ConfigPath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "could not read config file '%s'", opts.ConfigPath)
		os.Exit(1)
	}

	fmt.Printf("DBG %#v\n", cfg.InstanceName)

	return nil
}

func parseConfig(configPath string) (*Config, error) {
	cfgBytes, err := os.ReadFile(configPath)
	if err != nil {
		return nil, fmt.Errorf("failed to read config file: %w", err)
	}

	fmt.Printf("DBG %#v\n", string(cfgBytes))

	var cfg Config

	if err := yaml.Unmarshal(cfgBytes, &cfg); err != nil {
		return nil, fmt.Errorf("failed to parse config: %w", err)
	}

	fmt.Printf("DBG %#v\n", cfg)

	if cfg.Port == 0 {
		cfg.Port = defaultPort
	}

	if cfg.InstanceName == "" {
		cfg.InstanceName = defaultInstanceName

	}

	if cfg.Host == "" {
		cfg.Host = defaultHost
	}

	return &cfg, nil
}