package config

import (
	"errors"
	"fmt"
	"net/url"
	"os"
	"path/filepath"
	"reflect"

	"gopkg.in/ini.v1"
)

type Serve struct {
	Addr string `ini:"addr"`
}

type Database struct {
	Name     string `ini:"name"`
	User     string `ini:"user"`
	Password string `ini:"password"`
	Port     string `ini:"port"`
}

type Instance struct {
	Name         string `ini:"name"`
	ContactEmail string `ini:"contact-email"`
	BaseURL      string `ini:"base-url"`
}

type Config struct {
	Serve    Serve    `ini:"serve"`
	Database Database `ini:"database"`
	Instance Instance `ini:"instance"`
}

var (
	ErrBadConfig    = errors.New("no database configuration found")
	ErrBadConfigUrl = errors.New("bad url in config")
)

var systemConfigPath = "/etc/openstore/openstore.conf"

func DefaultPath() (string, error) {
	dir, err := os.UserConfigDir()
	if err != nil {
		return "", err
	}

	return filepath.Join(dir, "openstore", "openstore.conf"), nil
}

func Load(filename string) (*Config, error) {
	cfg, err := ini.LoadSources(ini.LoadOptions{
		Loose:              true,
		KeyValueDelimiters: "=",
	}, systemConfigPath, filename)
	if err != nil {
		return nil, err
	}

	config := new(Config)
	err = cfg.MapTo(config)
	if err != nil {
		return nil, err
	}

	u, err := url.Parse(config.Instance.BaseURL)
	if err != nil || u.Host == "" || u.Scheme == "" {
		return nil, fmt.Errorf(
			"%w: base-url must be an absolute url, got %s",
			ErrBadConfigUrl,
			config.Instance.BaseURL,
		)
	}

	v := reflect.ValueOf(config).Elem()
	t := v.Type()

	for i := 0; i < v.NumField(); i++ {
		key := t.Field(i).Name
		value := v.Field(i).Interface()
		if value == nil || value == "" {
			return nil, fmt.Errorf(
				"%w: config field %s empty",
				ErrBadConfig, key,
			)
		}
	}

	return config, nil
}