package pq

import (
	"os"
	"os/user"
	"path/filepath"
	"strings"
)

func defaultSettings() map[string]string {
	settings := make(map[string]string)

	settings[paramHost] = defaultHost()
	settings[paramPort] = "5432"

	// Default to the OS user name. Purposely ignoring err getting user name from
	// OS. The client application will simply have to specify the user in that
	// case (which they typically will be doing anyway).
	user, err := user.Current()
	appData := os.Getenv("APPDATA")
	if err == nil {
		// Windows gives us the username here as `DOMAIN\user` or `LOCALPCNAME\user`,
		// but the libpq default is just the `user` portion, so we strip off the first part.
		username := user.Username
		if strings.Contains(username, "\\") {
			username = username[strings.LastIndex(username, "\\")+1:]
		}

		settings[paramUser] = username
		settings[paramPassFile] = filepath.Join(appData, "postgresql", "pgpass.conf")
		settings[paramServiceFile] = filepath.Join(user.HomeDir, ".pg_service.conf")
	}

	settings[paramTargetSessionAttrs] = "any"

	settings[paramMinReadBufferSize] = "8192"
	settings[paramCpBufferSize] = "65536"
	// settings["client_encoding"] = DefaultClientEncoding
	return settings
}

// defaultHost attempts to mimic libpq's default host. libpq uses the default unix socket location on *nix and localhost
// on Windows. The default socket location is compiled into libpq. Since conn does not have access to that default it
// checks the existence of common locations.
func defaultHost() string {
	return "localhost"
}