package lsf

import (
	"fmt"
	"io/ioutil"
	"net/http"
	"net/url"
	"strings"

	"github.com/pkg/errors"
)

type Session struct {
	SID string
}

func (s *Session) Valid() (bool, error) {
	client := &http.Client{}
	req, err := http.NewRequest("GET", "https://lsf.hs-worms.de/qisserver/rds?state=user&type=8&topitem=functions&breadCrumbSource=portal", nil)
	if err != nil {
		return false, errors.Wrap(err, "could not prepare the request")
	}
	req.Header.Add("Cookie", fmt.Sprintf("JSESSIONID=%s", s.SID))
	resp, err := client.Do(req)
	if err != nil {
		return false, errors.Wrap(err, "could not do the request")
	}
	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return false, errors.Wrap(err, "could not read the response body")
	}

	if strings.Contains(string(b), "<u>L</u>ogout") {
		return true, nil
	}
	if strings.Contains(string(b), "<u>L</u>ogin") {
		return false, nil
	}
	return false, errors.New("unexpected response body")
}

func Login(username, password string) (*Session, error) {
	client := &http.Client{
		CheckRedirect: func(req *http.Request, via []*http.Request) error { // don't follow redirects
			return http.ErrUseLastResponse
		},
	}
	form := url.Values{}
	form.Add("asdf", username) // who wrote this backend? lol
	form.Add("fdsa", password)
	form.Add("submit", "Login")
	req, err := http.NewRequest("POST", "https://lsf.hs-worms.de/qisserver/rds?state=user&type=1&category=auth.login&startpage=portal.vm&breadCrumbSource=portal", strings.NewReader(form.Encode()))
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
	if err != nil {
		return nil, errors.Wrap(err, "could not prepare the login request")
	}
	resp, err := client.Do(req)
	if err != nil {
		return nil, errors.Wrap(err, "could not do the login request")
	}
	if resp.StatusCode == 302 {
		for _, c := range resp.Cookies() {
			if c.Name == "JSESSIONID" {
				return &Session{
					SID: c.Value,
				}, nil
			}
		}
		return nil, errors.New("no session cookie found")
	}
	if resp.StatusCode == 200 {
		return nil, errors.New("wrong credentials") // TODO or other errors
	}
	return nil, errors.New("unexpected response status code")
}