package oidc

import (
	"context"
	"errors"
	"net/http"
	"strings"
	"time"

	"github.com/zitadel/oidc/v3/pkg/oidc"
	"github.com/zitadel/oidc/v3/pkg/op"
	"github.com/zitadel/zitadel/internal/telemetry/tracing"
)

type Server struct {
	http.Handler
	storage *OPStorage
	*op.LegacyServer
}

func endpoints(endpointConfig *EndpointConfig) op.Endpoints {
	// some defaults. The new Server will disable enpoints that are nil.
	endpoints := op.Endpoints{
		Authorization:       op.NewEndpoint("/oauth/v2/authorize"),
		Token:               op.NewEndpoint("/oauth/v2/token"),
		Introspection:       op.NewEndpoint("/oauth/v2/introspect"),
		Userinfo:            op.NewEndpoint("/oidc/v1/userinfo"),
		Revocation:          op.NewEndpoint("/oauth/v2/revoke"),
		EndSession:          op.NewEndpoint("/oidc/v1/end_session"),
		JwksURI:             op.NewEndpoint("/oauth/v2/keys"),
		DeviceAuthorization: op.NewEndpoint("/oauth/v2/device_authorization"),
	}

	if endpointConfig == nil {
		return endpoints
	}
	if endpointConfig.Auth != nil {
		endpoints.Authorization = op.NewEndpointWithURL(endpointConfig.Auth.Path, endpointConfig.Auth.URL)
	}
	if endpointConfig.Token != nil {
		endpoints.Token = op.NewEndpointWithURL(endpointConfig.Token.Path, endpointConfig.Token.URL)
	}
	if endpointConfig.Introspection != nil {
		endpoints.Introspection = op.NewEndpointWithURL(endpointConfig.Introspection.Path, endpointConfig.Introspection.URL)
	}
	if endpointConfig.Userinfo != nil {
		endpoints.Userinfo = op.NewEndpointWithURL(endpointConfig.Userinfo.Path, endpointConfig.Userinfo.URL)
	}
	if endpointConfig.Revocation != nil {
		endpoints.Revocation = op.NewEndpointWithURL(endpointConfig.Revocation.Path, endpointConfig.Revocation.URL)
	}
	if endpointConfig.EndSession != nil {
		endpoints.EndSession = op.NewEndpointWithURL(endpointConfig.EndSession.Path, endpointConfig.EndSession.URL)
	}
	if endpointConfig.Keys != nil {
		endpoints.JwksURI = op.NewEndpointWithURL(endpointConfig.Keys.Path, endpointConfig.Keys.URL)
	}
	if endpointConfig.DeviceAuth != nil {
		endpoints.DeviceAuthorization = op.NewEndpointWithURL(endpointConfig.DeviceAuth.Path, endpointConfig.DeviceAuth.URL)
	}
	return endpoints
}

func (s *Server) IssuerFromRequest(r *http.Request) string {
	return s.Provider().IssuerFromRequest(r)
}

func (s *Server) Health(ctx context.Context, r *op.Request[struct{}]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.Health(ctx, r)
}

func (s *Server) Ready(ctx context.Context, r *op.Request[struct{}]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.Ready(ctx, r)
}

func (s *Server) Discovery(ctx context.Context, r *op.Request[struct{}]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.Discovery(ctx, r)
}

func (s *Server) Keys(ctx context.Context, r *op.Request[struct{}]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.Keys(ctx, r)
}

func (s *Server) VerifyAuthRequest(ctx context.Context, r *op.Request[oidc.AuthRequest]) (_ *op.ClientRequest[oidc.AuthRequest], err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.VerifyAuthRequest(ctx, r)
}

func (s *Server) Authorize(ctx context.Context, r *op.ClientRequest[oidc.AuthRequest]) (_ *op.Redirect, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.Authorize(ctx, r)
}

func (s *Server) DeviceAuthorization(ctx context.Context, r *op.ClientRequest[oidc.DeviceAuthorizationRequest]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.DeviceAuthorization(ctx, r)
}

func (s *Server) VerifyClient(ctx context.Context, r *op.Request[op.ClientCredentials]) (_ op.Client, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.VerifyClient(ctx, r)
}

func (s *Server) CodeExchange(ctx context.Context, r *op.ClientRequest[oidc.AccessTokenRequest]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.CodeExchange(ctx, r)
}

func (s *Server) RefreshToken(ctx context.Context, r *op.ClientRequest[oidc.RefreshTokenRequest]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.RefreshToken(ctx, r)
}

func (s *Server) JWTProfile(ctx context.Context, r *op.Request[oidc.JWTProfileGrantRequest]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.JWTProfile(ctx, r)
}

func (s *Server) TokenExchange(ctx context.Context, r *op.ClientRequest[oidc.TokenExchangeRequest]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.TokenExchange(ctx, r)
}

func (s *Server) ClientCredentialsExchange(ctx context.Context, r *op.ClientRequest[oidc.ClientCredentialsRequest]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.ClientCredentialsExchange(ctx, r)
}

func (s *Server) DeviceToken(ctx context.Context, r *op.ClientRequest[oidc.DeviceAccessTokenRequest]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.DeviceToken(ctx, r)
}

func (s *Server) authenticateResourceClient(ctx context.Context, cc *op.ClientCredentials) (clientID string, err error) {
	if cc.ClientAssertion != "" {
		verifier := op.NewJWTProfileVerifier(s.storage, op.IssuerFromContext(ctx), 1*time.Hour, time.Second)
		profile, err := op.VerifyJWTAssertion(ctx, cc.ClientAssertion, verifier)
		if err != nil {
			return "", err
		}
		return profile.Issuer, nil
	}

	if err = s.storage.AuthorizeClientIDSecret(ctx, cc.ClientID, cc.ClientSecret); err != nil {
		if err != nil {
			return "", err
		}
	}
	return cc.ClientID, nil
}

func (s *Server) getTokenIDAndSubject(ctx context.Context, accessToken string) (idToken, subject string, err error) {
	provider := s.Provider()
	tokenIDSubject, err := provider.Crypto().Decrypt(accessToken)
	if err == nil {
		splitToken := strings.Split(tokenIDSubject, ":")
		if len(splitToken) != 2 {
			return "", "", errors.New("invalid token format")
		}
		return splitToken[0], splitToken[1], nil
	}

	verifier := op.NewAccessTokenVerifier(op.IssuerFromContext(ctx), s.storage.keySet)
	accessTokenClaims, err := op.VerifyAccessToken[*oidc.AccessTokenClaims](ctx, accessToken, verifier)
	if err != nil {
		return "", "", err
	}
	return accessTokenClaims.JWTID, accessTokenClaims.Subject, nil
}

func (s *Server) Introspect(ctx context.Context, r *op.Request[op.IntrospectionRequest]) (_ *op.Response, err error) {
	clientID, err := s.authenticateResourceClient(ctx, r.Data.ClientCredentials)
	if err != nil {
		return nil, err
	}
	response := new(oidc.IntrospectionResponse)
	tokenID, subject, err := s.getTokenIDAndSubject(ctx, r.Data.Token)
	if err != nil {
		// TODO: log error
		return op.NewResponse(response), nil
	}
	err = s.storage.SetIntrospectionFromToken(ctx, response, tokenID, subject, clientID)
	if err != nil {
		return op.NewResponse(response), nil
	}
	response.Active = true
	return op.NewResponse(response), nil
}

func (s *Server) UserInfo(ctx context.Context, r *op.Request[oidc.UserInfoRequest]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.UserInfo(ctx, r)
}

func (s *Server) Revocation(ctx context.Context, r *op.ClientRequest[oidc.RevocationRequest]) (_ *op.Response, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.Revocation(ctx, r)
}

func (s *Server) EndSession(ctx context.Context, r *op.Request[oidc.EndSessionRequest]) (_ *op.Redirect, err error) {
	ctx, span := tracing.NewSpan(ctx)
	defer func() { span.EndWithError(err) }()

	return s.LegacyServer.EndSession(ctx, r)
}