package auth

import (
	"bytes"
	"context"
	"encoding/gob"
	"net/http"

	"github.com/danieljoos/wincred"
	"golang.org/x/oauth2"
)

type Credentials struct {
	GoogleToken *oauth2.Token
	GUID        string
	UofgPass    string
}

const credential_name = "uofgsync"

func read_credentials() (*Credentials, error) {
	// read from windows credential manager
	cred, err := wincred.GetGenericCredential(credential_name)
	if err != nil {
		return nil, err
	}

	// deserialize the credentials
	var c Credentials
	dec := gob.NewDecoder(bytes.NewReader(cred.CredentialBlob))
	if err := dec.Decode(&c); err != nil {
		return nil, err
	}

	return &c, nil
}

func save_credentials(credentials Credentials) error {
	// serialize the credentials
	var buf bytes.Buffer
	enc := gob.NewEncoder(&buf)
	if err := enc.Encode(credentials); err != nil {
		return err
	}

	// save to windows credential manager
	cred := wincred.NewGenericCredential(credential_name)
	cred.CredentialBlob = buf.Bytes()
	if err := cred.Write(); err != nil {
		return err
	}

	return nil
}

func GetCredentials(config *oauth2.Config) (*Credentials, error) {
	creds, err := read_credentials()
	if err != nil {
		google := fetch_google_token(config)
		guid, uofg_pass, err := collect_uofg()
		if err != nil {
			return nil, err
		}
		creds = &Credentials{
			GoogleToken: google,
			GUID:        guid,
			UofgPass:    uofg_pass,
		}
		save_credentials(*creds)
	}
	return creds, nil
}

func GetGoogleClient(config *oauth2.Config, token *oauth2.Token) *http.Client {
	return config.Client(context.Background(), token)
}