// This file is part of MinIO Console Server
// Copyright (c) 2021 MinIO, Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//

package restapi

import (
	"context"
	"errors"
	"fmt"
	"net/http"
	"net/url"
	"os"

	"github.com/minio/console/pkg/utils"

	xhttp "github.com/minio/console/pkg/http"

	"github.com/go-openapi/runtime/middleware"
	"github.com/minio/console/models"
	"github.com/minio/console/pkg/subnet"
	"github.com/minio/console/restapi/operations"
	subnetApi "github.com/minio/console/restapi/operations/subnet"
	"github.com/minio/madmin-go/v3"
)

func registerSubnetHandlers(api *operations.ConsoleAPI) {
	// Get subnet login handler
	api.SubnetSubnetLoginHandler = subnetApi.SubnetLoginHandlerFunc(func(params subnetApi.SubnetLoginParams, session *models.Principal) middleware.Responder {
		resp, err := GetSubnetLoginResponse(session, params)
		if err != nil {
			return subnetApi.NewSubnetLoginDefault(err.Code).WithPayload(err.APIError)
		}
		return subnetApi.NewSubnetLoginOK().WithPayload(resp)
	})
	// Get subnet login with MFA handler
	api.SubnetSubnetLoginMFAHandler = subnetApi.SubnetLoginMFAHandlerFunc(func(params subnetApi.SubnetLoginMFAParams, session *models.Principal) middleware.Responder {
		resp, err := GetSubnetLoginWithMFAResponse(session, params)
		if err != nil {
			return subnetApi.NewSubnetLoginMFADefault(err.Code).WithPayload(err.APIError)
		}
		return subnetApi.NewSubnetLoginMFAOK().WithPayload(resp)
	})
	// Get subnet register
	api.SubnetSubnetRegisterHandler = subnetApi.SubnetRegisterHandlerFunc(func(params subnetApi.SubnetRegisterParams, session *models.Principal) middleware.Responder {
		err := GetSubnetRegisterResponse(session, params)
		if err != nil {
			return subnetApi.NewSubnetRegisterDefault(err.Code).WithPayload(err.APIError)
		}
		return subnetApi.NewSubnetRegisterOK()
	})
	// Get subnet info
	api.SubnetSubnetInfoHandler = subnetApi.SubnetInfoHandlerFunc(func(params subnetApi.SubnetInfoParams, session *models.Principal) middleware.Responder {
		resp, err := GetSubnetInfoResponse(session, params)
		if err != nil {
			return subnetApi.NewSubnetInfoDefault(err.Code).WithPayload(err.APIError)
		}
		return subnetApi.NewSubnetInfoOK().WithPayload(resp)
	})
	// Get subnet registration token
	api.SubnetSubnetRegTokenHandler = subnetApi.SubnetRegTokenHandlerFunc(func(params subnetApi.SubnetRegTokenParams, session *models.Principal) middleware.Responder {
		resp, err := GetSubnetRegTokenResponse(session, params)
		if err != nil {
			return subnetApi.NewSubnetRegTokenDefault(err.Code).WithPayload(err.APIError)
		}
		return subnetApi.NewSubnetRegTokenOK().WithPayload(resp)
	})

	api.SubnetSubnetAPIKeyHandler = subnetApi.SubnetAPIKeyHandlerFunc(func(params subnetApi.SubnetAPIKeyParams, session *models.Principal) middleware.Responder {
		resp, err := GetSubnetAPIKeyResponse(session, params)
		if err != nil {
			return subnetApi.NewSubnetAPIKeyDefault(err.Code).WithPayload(err.APIError)
		}
		return subnetApi.NewSubnetAPIKeyOK().WithPayload(resp)
	})
}

const EnvSubnetLicense = "CONSOLE_SUBNET_LICENSE"

func SubnetRegisterWithAPIKey(ctx context.Context, minioClient MinioAdmin, apiKey string) (bool, error) {
	serverInfo, err := minioClient.serverInfo(ctx)
	if err != nil {
		return false, err
	}
	clientIP := utils.ClientIPFromContext(ctx)
	registerResult, err := subnet.Register(GetConsoleHTTPClient("", clientIP), serverInfo, apiKey, "", "")
	if err != nil {
		return false, err
	}
	// Keep existing subnet proxy if exists
	subnetKey, err := GetSubnetKeyFromMinIOConfig(ctx, minioClient)
	if err != nil {
		return false, err
	}
	configStr := fmt.Sprintf("subnet license=%s api_key=%s proxy=%s", registerResult.License, registerResult.APIKey, subnetKey.Proxy)
	_, err = minioClient.setConfigKV(ctx, configStr)
	if err != nil {
		return false, err
	}
	// cluster registered correctly
	return true, nil
}

func SubnetLogin(client xhttp.ClientI, username, password string) (string, string, error) {
	tokens, err := subnet.Login(client, username, password)
	if err != nil {
		return "", "", err
	}
	if tokens.MfaToken != "" {
		// user needs to complete login flow using mfa
		return "", tokens.MfaToken, nil
	}
	if tokens.AccessToken != "" {
		// register token to minio
		return tokens.AccessToken, "", nil
	}
	return "", "", errors.New("something went wrong")
}

func GetSubnetLoginResponse(session *models.Principal, params subnetApi.SubnetLoginParams) (*models.SubnetLoginResponse, *CodedAPIError) {
	ctx, cancel := context.WithCancel(params.HTTPRequest.Context())
	defer cancel()
	mAdmin, err := NewMinioAdminClient(params.HTTPRequest.Context(), session)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	return subnetLoginResponse(ctx, AdminClient{Client: mAdmin}, params)
}

func subnetLoginResponse(ctx context.Context, minioClient MinioAdmin, params subnetApi.SubnetLoginParams) (*models.SubnetLoginResponse, *CodedAPIError) {
	subnetHTTPClient, err := GetSubnetHTTPClient(ctx, minioClient)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	apiKey := params.Body.APIKey
	if apiKey != "" {
		registered, err := SubnetRegisterWithAPIKey(ctx, minioClient, apiKey)
		if err != nil {
			return nil, ErrorWithContext(ctx, err)
		}
		return &models.SubnetLoginResponse{
			Registered:    registered,
			Organizations: []*models.SubnetOrganization{},
		}, nil
	}
	username := params.Body.Username
	password := params.Body.Password
	if username != "" && password != "" {
		token, mfa, err := SubnetLogin(subnetHTTPClient, username, password)
		if err != nil {
			return nil, ErrorWithContext(ctx, err)
		}
		return &models.SubnetLoginResponse{
			MfaToken:      mfa,
			AccessToken:   token,
			Organizations: []*models.SubnetOrganization{},
		}, nil
	}
	return nil, ErrorWithContext(ctx, ErrDefault)
}

type SubnetRegistration struct {
	AccessToken   string
	MFAToken      string
	Organizations []models.SubnetOrganization
}

func SubnetLoginWithMFA(client xhttp.ClientI, username, mfaToken, otp string) (*models.SubnetLoginResponse, error) {
	tokens, err := subnet.LoginWithMFA(client, username, mfaToken, otp)
	if err != nil {
		return nil, err
	}
	if tokens.AccessToken != "" {
		organizations, errOrg := subnet.GetOrganizations(client, tokens.AccessToken)
		if errOrg != nil {
			return nil, errOrg
		}
		return &models.SubnetLoginResponse{
			AccessToken:   tokens.AccessToken,
			Organizations: organizations,
		}, nil
	}
	return nil, errors.New("something went wrong")
}

// GetSubnetHTTPClient will return a client with proxy if configured, otherwise will return the default console http client
func GetSubnetHTTPClient(ctx context.Context, minioClient MinioAdmin) (*xhttp.Client, error) {
	clientIP := utils.ClientIPFromContext(ctx)
	subnetHTTPClient := GetConsoleHTTPClient("", clientIP)
	subnetKey, err := GetSubnetKeyFromMinIOConfig(ctx, minioClient)
	if err != nil {
		return nil, err
	}

	proxy := getSubnetProxy()
	if subnetKey.Proxy != "" {
		proxy = subnetKey.Proxy
	}
	if proxy != "" {
		subnetProxyURL, err := url.Parse(proxy)
		if err != nil {
			return nil, err
		}
		subnetHTTPClient.Transport.(*ConsoleTransport).Transport.Proxy = http.ProxyURL(subnetProxyURL)
	}

	clientI := &xhttp.Client{
		Client: subnetHTTPClient,
	}
	return clientI, nil
}

func GetSubnetLoginWithMFAResponse(session *models.Principal, params subnetApi.SubnetLoginMFAParams) (*models.SubnetLoginResponse, *CodedAPIError) {
	ctx, cancel := context.WithCancel(params.HTTPRequest.Context())
	defer cancel()
	mAdmin, err := NewMinioAdminClient(params.HTTPRequest.Context(), session)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	minioClient := AdminClient{Client: mAdmin}
	return subnetLoginWithMFAResponse(ctx, minioClient, params)
}

func subnetLoginWithMFAResponse(ctx context.Context, minioClient MinioAdmin, params subnetApi.SubnetLoginMFAParams) (*models.SubnetLoginResponse, *CodedAPIError) {
	subnetHTTPClient, err := GetSubnetHTTPClient(ctx, minioClient)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	resp, err := SubnetLoginWithMFA(subnetHTTPClient, *params.Body.Username, *params.Body.MfaToken, *params.Body.Otp)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	return resp, nil
}

func GetSubnetKeyFromMinIOConfig(ctx context.Context, minioClient MinioAdmin) (*subnet.LicenseTokenConfig, error) {
	buf, err := minioClient.getConfigKV(ctx, madmin.SubnetSubSys)
	if err != nil {
		return nil, err
	}

	subSysConfigs, err := madmin.ParseServerConfigOutput(string(buf))
	if err != nil {
		return nil, err
	}

	for _, scfg := range subSysConfigs {
		if scfg.Target == "" {
			res := subnet.LicenseTokenConfig{}
			res.APIKey, _ = scfg.Lookup("api_key")
			res.License, _ = scfg.Lookup("license")
			res.Proxy, _ = scfg.Lookup("proxy")
			return &res, nil
		}
	}

	return nil, errors.New("unable to find subnet configuration")
}

func GetSubnetRegister(ctx context.Context, minioClient MinioAdmin, httpClient xhttp.ClientI, params subnetApi.SubnetRegisterParams) error {
	serverInfo, err := minioClient.serverInfo(ctx)
	if err != nil {
		return err
	}
	registerResult, err := subnet.Register(httpClient, serverInfo, "", *params.Body.Token, *params.Body.AccountID)
	if err != nil {
		return err
	}
	// Keep existing subnet proxy if exists
	subnetKey, err := GetSubnetKeyFromMinIOConfig(ctx, minioClient)
	if err != nil {
		return err
	}
	configStr := fmt.Sprintf("subnet license=%s api_key=%s proxy=%s", registerResult.License, registerResult.APIKey, subnetKey.Proxy)
	_, err = minioClient.setConfigKV(ctx, configStr)
	if err != nil {
		return err
	}
	return nil
}

func GetSubnetRegisterResponse(session *models.Principal, params subnetApi.SubnetRegisterParams) *CodedAPIError {
	ctx, cancel := context.WithCancel(params.HTTPRequest.Context())
	defer cancel()
	mAdmin, err := NewMinioAdminClient(params.HTTPRequest.Context(), session)
	if err != nil {
		return ErrorWithContext(ctx, err)
	}
	adminClient := AdminClient{Client: mAdmin}
	return subnetRegisterResponse(ctx, adminClient, params)
}

func subnetRegisterResponse(ctx context.Context, minioClient MinioAdmin, params subnetApi.SubnetRegisterParams) *CodedAPIError {
	subnetHTTPClient, err := GetSubnetHTTPClient(ctx, minioClient)
	if err != nil {
		return ErrorWithContext(ctx, err)
	}
	err = GetSubnetRegister(ctx, minioClient, subnetHTTPClient, params)
	if err != nil {
		return ErrorWithContext(ctx, err)
	}
	return nil
}

var ErrSubnetLicenseNotFound = errors.New("license not found")

func GetSubnetInfoResponse(session *models.Principal, params subnetApi.SubnetInfoParams) (*models.License, *CodedAPIError) {
	ctx, cancel := context.WithCancel(params.HTTPRequest.Context())
	defer cancel()
	clientIP := utils.ClientIPFromContext(ctx)
	client := &xhttp.Client{
		Client: GetConsoleHTTPClient("", clientIP),
	}
	// license gets seeded to us by MinIO
	seededLicense := os.Getenv(EnvSubnetLicense)
	// if it's missing, we will gracefully fallback to attempt to fetch it from MinIO
	if seededLicense == "" {
		mAdmin, err := NewMinioAdminClient(params.HTTPRequest.Context(), session)
		if err != nil {
			return nil, ErrorWithContext(ctx, err)
		}
		adminClient := AdminClient{Client: mAdmin}

		configBytes, err := adminClient.getConfigKV(params.HTTPRequest.Context(), "subnet")
		if err != nil {
			return nil, ErrorWithContext(ctx, err)
		}
		subSysConfigs, err := madmin.ParseServerConfigOutput(string(configBytes))
		if err != nil {
			return nil, ErrorWithContext(ctx, err)
		}
		// search for licese
		for _, v := range subSysConfigs {
			for _, sv := range v.KV {
				if sv.Key == "license" {
					seededLicense = sv.Value
				}
			}
		}
	}
	// still empty means not found
	if seededLicense == "" {
		return nil, ErrorWithContext(ctx, ErrSubnetLicenseNotFound)
	}

	licenseInfo, err := subnet.ParseLicense(client, seededLicense)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	license := &models.License{
		Email:           licenseInfo.Email,
		AccountID:       licenseInfo.AccountID,
		StorageCapacity: licenseInfo.StorageCapacity,
		Plan:            licenseInfo.Plan,
		ExpiresAt:       licenseInfo.ExpiresAt.String(),
		Organization:    licenseInfo.Organization,
	}
	return license, nil
}

func GetSubnetRegToken(ctx context.Context, minioClient MinioAdmin) (string, error) {
	serverInfo, err := minioClient.serverInfo(ctx)
	if err != nil {
		return "", err
	}
	regInfo := subnet.GetClusterRegInfo(serverInfo)
	regToken, err := subnet.GenerateRegToken(regInfo)
	if err != nil {
		return "", err
	}
	return regToken, nil
}

func GetSubnetRegTokenResponse(session *models.Principal, params subnetApi.SubnetRegTokenParams) (*models.SubnetRegTokenResponse, *CodedAPIError) {
	ctx, cancel := context.WithCancel(params.HTTPRequest.Context())
	defer cancel()
	mAdmin, err := NewMinioAdminClient(params.HTTPRequest.Context(), session)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	adminClient := AdminClient{Client: mAdmin}
	return subnetRegTokenResponse(ctx, adminClient)
}

func subnetRegTokenResponse(ctx context.Context, minioClient MinioAdmin) (*models.SubnetRegTokenResponse, *CodedAPIError) {
	token, err := GetSubnetRegToken(ctx, minioClient)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	return &models.SubnetRegTokenResponse{
		RegToken: token,
	}, nil
}

func GetSubnetAPIKeyResponse(session *models.Principal, params subnetApi.SubnetAPIKeyParams) (*models.APIKey, *CodedAPIError) {
	ctx, cancel := context.WithCancel(params.HTTPRequest.Context())
	defer cancel()
	mAdmin, err := NewMinioAdminClient(params.HTTPRequest.Context(), session)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	adminClient := AdminClient{Client: mAdmin}
	return subnetAPIKeyResponse(ctx, adminClient, params)
}

func subnetAPIKeyResponse(ctx context.Context, minioClient MinioAdmin, params subnetApi.SubnetAPIKeyParams) (*models.APIKey, *CodedAPIError) {
	subnetHTTPClient, err := GetSubnetHTTPClient(ctx, minioClient)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	token := params.HTTPRequest.URL.Query().Get("token")
	apiKey, err := subnet.GetAPIKey(subnetHTTPClient, token)
	if err != nil {
		return nil, ErrorWithContext(ctx, err)
	}
	return &models.APIKey{APIKey: apiKey}, nil
}