package graphql

import (
	"context"
	"encoding/json"
	"net/http"
	"time"

	"github.com/pkg/errors"
	"github.com/xlzd/gotp"

	"git.lehouerou.net/laurent/sorare/bcrypt"
)

const bCryptCost = 11

func (c *Client) getSaltFromEmail(ctx context.Context, email string) (string, error) {
	var response struct {
		Salt string `json:"salt"`
	}
	req, err := http.NewRequestWithContext(
		ctx,
		http.MethodGet,
		"https://api.sorare.com/api/v1/users/"+email,
		nil,
	)
	if err != nil {
		return "", errors.Wrap(err, "creating request")
	}
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return "", errors.Wrap(err, "executing request")
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return "", errors.Errorf("executing request failed with status code %d", resp.StatusCode)
	}
	err = json.NewDecoder(resp.Body).Decode(&response)
	if err != nil {
		return "", errors.Wrap(err, "decoding response")
	}
	return response.Salt[7:], nil
}

func hashPasswordWithSalt(password, salt string) (string, error) {
	hashed, err := bcrypt.GenerateFromPasswordAndSalt([]byte(password), []byte(salt), bCryptCost)
	if err != nil {
		return "", err
	}
	return string(hashed), nil
}

type JwtToken struct {
	Token     string
	ExpiredAt time.Time
}

type SignIn struct {
	CurrentUser struct {
		Slug     string
		JwtToken JwtToken `graphql:"jwtToken(aud: $aud)"`
	} `graphql:"currentUser"`
	OtpSessionChallenge string
	Errors              []struct {
		Message string
	} `graphql:"errors"`
}

type signInInput struct {
	Email               string `json:"email,omitempty"`
	Password            string `json:"password,omitempty"`
	OtpSessionChallenge string `json:"otpSessionChallenge,omitempty"`
	OtpAttempt          string `json:"otpAttempt,omitempty"`
}

type SignInParams struct {
	Input signInInput `graphql:"input"`
}

type SignInMutation struct {
	*Mutation[SignIn, SignInParams]
}

func NewSignInMutation(c *Client, audience string) *SignInMutation {
	return &SignInMutation{
		NewMutation[SignIn, SignInParams](c, "signIn").WithQueryParam("aud", audience),
	}
}

func (c *Client) getNewToken(
	ctx context.Context,
	email string,
	password string,
	audience string,
	otp string,
) (JwtToken, error) {

	salt, err := c.getSaltFromEmail(ctx, email)
	if err != nil {
		return JwtToken{}, errors.Wrap(err, "getting salt from email")
	}
	hashed, err := hashPasswordWithSalt(password, salt)
	if err != nil {
		return JwtToken{}, errors.Wrap(err, "hashing password with salt")
	}

	signInMutation := NewSignInMutation(c, audience)
	res, err := signInMutation.Execute(ctx, SignInParams{
		Input: signInInput{
			Email:    email,
			Password: hashed,
		},
	})
	if err != nil {
		return JwtToken{}, errors.Wrap(err, "executing signin mutation with email and password")
	}

	if len(res.Errors) == 0 {
		if res.CurrentUser.JwtToken.Token == "" {
			return JwtToken{}, errors.New(
				"no errors & no jwt token returned on email/password mutation",
			)
		}
		return res.CurrentUser.JwtToken, nil
	}

	if res.Errors[0].Message == "invalid" {
		return JwtToken{}, errors.New("invalid email or password")
	}

	if res.Errors[0].Message == "2fa_missing" {
		if otp == "" {
			return JwtToken{}, errors.New("2fa missing & no otp provided")
		}
		token := gotp.NewDefaultTOTP(otp).Now()

		signInMutation := NewSignInMutation(c, audience)
		resOtp, err := signInMutation.Execute(ctx, SignInParams{
			Input: signInInput{
				OtpSessionChallenge: res.OtpSessionChallenge,
				OtpAttempt:          token,
			},
		})
		if err != nil {
			return JwtToken{}, err
		}

		if len(resOtp.Errors) == 0 {
			if resOtp.CurrentUser.JwtToken.Token == "" {
				return JwtToken{}, errors.New("no errors & no jwt token returned on otp mutation")
			}
			return resOtp.CurrentUser.JwtToken, nil
		}
		return JwtToken{}, errors.Errorf("validating otp: %s", resOtp.Errors[0].Message)
	}
	return JwtToken{}, errors.Errorf("unmanaged error: %s", res.Errors[0].Message)
}

func (c *Client) Authenticate(
	ctx context.Context,
	email string,
	password string,
	audience string,
	otp string,
) error {
	token, err := c.getNewToken(ctx, email, password, audience, otp)
	if err != nil {
		return errors.Wrap(err, "getting new jwt token")
	}
	c.SetJWTToken(token, audience)
	return nil
}