package org.hl7.fhir.common.hapi.validation.validator;

import ca.uhn.fhir.context.FhirContext;
import ca.uhn.fhir.context.FhirVersionEnum;
import ca.uhn.fhir.context.support.DefaultProfileValidationSupport;
import ca.uhn.fhir.context.support.IValidationSupport;
import ca.uhn.fhir.validation.IInstanceValidatorModule;
import ca.uhn.fhir.validation.IValidationContext;
import jakarta.annotation.Nonnull;
import org.apache.commons.lang3.Validate;
import org.hl7.fhir.exceptions.FHIRException;
import org.hl7.fhir.exceptions.PathEngineException;
import org.hl7.fhir.r5.fhirpath.FHIRPathEngine;
import org.hl7.fhir.r5.fhirpath.FHIRPathUtilityClasses.FunctionDetails;
import org.hl7.fhir.r5.fhirpath.TypeDetails;
import org.hl7.fhir.r5.model.Base;
import org.hl7.fhir.r5.model.ValueSet;
import org.hl7.fhir.r5.utils.validation.IValidationPolicyAdvisor;
import org.hl7.fhir.r5.utils.validation.IValidatorResourceFetcher;
import org.hl7.fhir.r5.utils.validation.constants.BestPracticeWarningLevel;
import org.hl7.fhir.utilities.validation.ValidationMessage;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

@SuppressWarnings({"PackageAccessibility", "Duplicates"})
public class FhirInstanceValidator extends BaseValidatorBridge implements IInstanceValidatorModule {

        private boolean myAnyExtensionsAllowed = true;
        private BestPracticeWarningLevel myBestPracticeWarningLevel;
        private IValidationSupport myValidationSupport;
        private boolean noTerminologyChecks = false;
        private boolean noExtensibleWarnings = false;
        private boolean noBindingMsgSuppressed = false;
        private volatile VersionSpecificWorkerContextWrapper myWrappedWorkerContext;
        private boolean errorForUnknownProfiles = true;

        private boolean assumeValidRestReferences;
        private List<String> myExtensionDomains = Collections.emptyList();
        private IValidatorResourceFetcher validatorResourceFetcher;
        private IValidationPolicyAdvisor validatorPolicyAdvisor = new FhirDefaultPolicyAdvisor();

        /**
         * Constructor
         * <p>
         * Uses {@link DefaultProfileValidationSupport} for {@link IValidationSupport validation support}
         */
        public FhirInstanceValidator(FhirContext theContext) {
                this(theContext.getValidationSupport());
        }

        /**
         * Constructor which uses the given validation support
         *
         * @param theValidationSupport The validation support
         */
        public FhirInstanceValidator(IValidationSupport theValidationSupport) {
                if (theValidationSupport.getFhirContext().getVersion().getVersion() == FhirVersionEnum.DSTU2) {
                        myValidationSupport = new HapiToHl7OrgDstu2ValidatingSupportWrapper(theValidationSupport);
                } else {
                        myValidationSupport = theValidationSupport;
                }
        }

        /**
         * Every element in a resource or data type includes an optional <it>extension</it> child element
         * which is identified by it's {@code url attribute}. There exists a number of predefined
         * extension urls or extension domains:<ul>
         * <li>any url which contains {@code example.org}, {@code nema.org}, or {@code acme.com}.</li>
         * <li>any url which starts with {@code http://hl7.org/fhir/StructureDefinition/}.</li>
         * </ul>
         * It is possible to extend this list of known extension by defining custom extensions:
         * Any url which starts which one of the elements in the list of custom extension domains is
         * considered as known.
         * <p>
         * Any unknown extension domain will result in an information message when validating a resource.
         * </p>
         */
        public FhirInstanceValidator setCustomExtensionDomains(List<String> extensionDomains) {
                this.myExtensionDomains = extensionDomains;
                return this;
        }

        /**
         * Every element in a resource or data type includes an optional <it>extension</it> child element
         * which is identified by it's {@code url attribute}. There exists a number of predefined
         * extension urls or extension domains:<ul>
         * <li>any url which contains {@code example.org}, {@code nema.org}, or {@code acme.com}.</li>
         * <li>any url which starts with {@code http://hl7.org/fhir/StructureDefinition/}.</li>
         * </ul>
         * It is possible to extend this list of known extension by defining custom extensions:
         * Any url which starts which one of the elements in the list of custom extension domains is
         * considered as known.
         * <p>
         * Any unknown extension domain will result in an information message when validating a resource.
         * </p>
         */
        public FhirInstanceValidator setCustomExtensionDomains(String... extensionDomains) {
                this.myExtensionDomains = Arrays.asList(extensionDomains);
                return this;
        }

        /**
         * Returns the "best practice" warning level (default is {@link BestPracticeWarningLevel#Hint}).
         * <p>
         * The FHIR Instance Validator has a number of checks for best practices in terms of FHIR usage. If this setting is
         * set to {@link BestPracticeWarningLevel#Error}, any resource data which does not meet these best practices will be
         * reported at the ERROR level. If this setting is set to {@link BestPracticeWarningLevel#Ignore}, best practice
         * guielines will be ignored.
         * </p>
         *
         * @see #setBestPracticeWarningLevel(BestPracticeWarningLevel)
         */
        public BestPracticeWarningLevel getBestPracticeWarningLevel() {
                return myBestPracticeWarningLevel;
        }

        /**
         * Sets the "best practice warning level". When validating, any deviations from best practices will be reported at
         * this level.
         * <p>
         * The FHIR Instance Validator has a number of checks for best practices in terms of FHIR usage. If this setting is
         * set to {@link BestPracticeWarningLevel#Error}, any resource data which does not meet these best practices will be
         * reported at the ERROR level. If this setting is set to {@link BestPracticeWarningLevel#Ignore}, best practice
         * guielines will be ignored.
         * </p>
         *
         * @param theBestPracticeWarningLevel The level, must not be <code>null</code>
         */
        public void setBestPracticeWarningLevel(BestPracticeWarningLevel theBestPracticeWarningLevel) {
                Validate.notNull(theBestPracticeWarningLevel);
                myBestPracticeWarningLevel = theBestPracticeWarningLevel;
        }

        /**
         * Returns the {@link IValidationSupport validation support} in use by this validator. Default is an instance of
         * DefaultProfileValidationSupport if the no-arguments constructor for this object was used.
         */
        public IValidationSupport getValidationSupport() {
                return myValidationSupport;
        }

        /**
         * Sets the {@link IValidationSupport validation support} in use by this validator. Default is an instance of
         * DefaultProfileValidationSupport if the no-arguments constructor for this object was used.
         */
        public void setValidationSupport(IValidationSupport theValidationSupport) {
                myValidationSupport = theValidationSupport;
                myWrappedWorkerContext = null;
        }

        /**
         * If set to {@literal true} (default is true) extensions which are not known to the
         * validator (e.g. because they have not been explicitly declared in a profile) will
         * be validated but will not cause an error.
         */
        public boolean isAnyExtensionsAllowed() {
                return myAnyExtensionsAllowed;
        }

        /**
         * If set to {@literal true} (default is true) extensions which are not known to the
         * validator (e.g. because they have not been explicitly declared in a profile) will
         * be validated but will not cause an error.
         */
        public void setAnyExtensionsAllowed(boolean theAnyExtensionsAllowed) {
                myAnyExtensionsAllowed = theAnyExtensionsAllowed;
        }

        public boolean isErrorForUnknownProfiles() {
                return errorForUnknownProfiles;
        }

        public void setErrorForUnknownProfiles(boolean errorForUnknownProfiles) {
                this.errorForUnknownProfiles = errorForUnknownProfiles;
        }

        /**
         * If set to {@literal true} (default is false) the valueSet will not be validate
         */
        public boolean isNoTerminologyChecks() {
                return noTerminologyChecks;
        }

        /**
         * If set to {@literal true} (default is false) the valueSet will not be validate
         */
        public void setNoTerminologyChecks(final boolean theNoTerminologyChecks) {
                noTerminologyChecks = theNoTerminologyChecks;
        }

        /**
         * If set to {@literal true} (default is false) no extensible warnings suppressed
         */
        public boolean isNoExtensibleWarnings() {
                return noExtensibleWarnings;
        }

        /**
         * If set to {@literal true} (default is false) no extensible warnings is suppressed
         */
        public void setNoExtensibleWarnings(final boolean theNoExtensibleWarnings) {
                noExtensibleWarnings = theNoExtensibleWarnings;
        }

        /**
         * If set to {@literal true} (default is false) no binding message is suppressed
         */
        public boolean isNoBindingMsgSuppressed() {
                return noBindingMsgSuppressed;
        }

        /**
         * If set to {@literal true} (default is false) no binding message is suppressed
         */
        public void setNoBindingMsgSuppressed(final boolean theNoBindingMsgSuppressed) {
                noBindingMsgSuppressed = theNoBindingMsgSuppressed;
        }

        public List<String> getExtensionDomains() {
                return myExtensionDomains;
        }

        @Override
        protected List<ValidationMessage> validate(IValidationContext<?> theValidationCtx) {
                VersionSpecificWorkerContextWrapper wrappedWorkerContext = provideWorkerContext();

                return new ValidatorWrapper()
                                .setAnyExtensionsAllowed(isAnyExtensionsAllowed())
                                .setBestPracticeWarningLevel(getBestPracticeWarningLevel())
                                .setErrorForUnknownProfiles(isErrorForUnknownProfiles())
                                .setExtensionDomains(getExtensionDomains())
                                .setValidationPolicyAdvisor(validatorPolicyAdvisor)
                                .setNoTerminologyChecks(isNoTerminologyChecks())
                                .setNoExtensibleWarnings(isNoExtensibleWarnings())
                                .setNoBindingMsgSuppressed(isNoBindingMsgSuppressed())
                                .setValidatorResourceFetcher(getValidatorResourceFetcher())
                                .setAssumeValidRestReferences(isAssumeValidRestReferences())
                                .validate(wrappedWorkerContext, theValidationCtx);
        }

        @Nonnull
        protected VersionSpecificWorkerContextWrapper provideWorkerContext() {
                VersionSpecificWorkerContextWrapper wrappedWorkerContext = myWrappedWorkerContext;
                if (wrappedWorkerContext == null) {
                        wrappedWorkerContext =
                                        VersionSpecificWorkerContextWrapper.newVersionSpecificWorkerContextWrapper(myValidationSupport);
                }
                myWrappedWorkerContext = wrappedWorkerContext;
                return wrappedWorkerContext;
        }

        public IValidationPolicyAdvisor getValidatorPolicyAdvisor() {
                return validatorPolicyAdvisor;
        }

        public void setValidatorPolicyAdvisor(IValidationPolicyAdvisor validatorPolicyAdvisor) {
                this.validatorPolicyAdvisor = validatorPolicyAdvisor;
        }

        public IValidatorResourceFetcher getValidatorResourceFetcher() {
                return validatorResourceFetcher;
        }

        public void setValidatorResourceFetcher(IValidatorResourceFetcher validatorResourceFetcher) {
                this.validatorResourceFetcher = validatorResourceFetcher;
        }

        public boolean isAssumeValidRestReferences() {
                return assumeValidRestReferences;
        }

        public void setAssumeValidRestReferences(boolean assumeValidRestReferences) {
                this.assumeValidRestReferences = assumeValidRestReferences;
        }

        /**
         * Clear any cached data held by the validator or any of its internal stores. This is mostly intended
         * for unit tests, but could be used for production uses too.
         */
        public void invalidateCaches() {
                myValidationSupport.invalidateCaches();
                if (myWrappedWorkerContext != null) {
                        myWrappedWorkerContext.invalidateCaches();
                }
        }

        public static class NullEvaluationContext implements FHIRPathEngine.IEvaluationContext {

                @Override
                public List<Base> resolveConstant(
                                FHIRPathEngine engine, Object appContext, String name, boolean beforeContext, boolean explicitConstant)
                                throws PathEngineException {
                        return Collections.emptyList();
                }

                @Override
                public TypeDetails resolveConstantType(
                                FHIRPathEngine engine, Object appContext, String name, boolean explicitConstant)
                                throws PathEngineException {
                        return null;
                }

                @Override
                public boolean log(String argument, List<Base> focus) {
                        return false;
                }

                @Override
                public FunctionDetails resolveFunction(FHIRPathEngine engine, String functionName) {
                        return null;
                }

                @Override
                public TypeDetails checkFunction(
                                FHIRPathEngine engine,
                                Object appContext,
                                String functionName,
                                TypeDetails focus,
                                List<TypeDetails> parameters)
                                throws PathEngineException {
                        return null;
                }

                @Override
                public List<Base> executeFunction(
                                FHIRPathEngine engine,
                                Object appContext,
                                List<Base> focus,
                                String functionName,
                                List<List<Base>> parameters) {
                        return null;
                }

                @Override
                public Base resolveReference(FHIRPathEngine engine, Object appContext, String url, Base refContext)
                                throws FHIRException {
                        return null;
                }

                @Override
                public boolean conformsToProfile(FHIRPathEngine engine, Object appContext, Base item, String url)
                                throws FHIRException {
                        return false;
                }

                @Override
                public ValueSet resolveValueSet(FHIRPathEngine engine, Object appContext, String url) {
                        return null;
                }

                @Override
                public boolean paramIsType(String name, int index) {
                        return false;
                }
        }
}