/*
 * #%L
 * HAPI FHIR - Core Library
 * %%
 * Copyright (C) 2014 - 2024 Smile CDR, Inc.
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */
package ca.uhn.fhir.validation;

import ca.uhn.fhir.context.FhirContext;
import ca.uhn.fhir.rest.api.Constants;
import ca.uhn.fhir.util.OperationOutcomeUtil;
import org.hl7.fhir.instance.model.api.IBase;
import org.hl7.fhir.instance.model.api.IBaseOperationOutcome;

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

import static org.apache.commons.lang3.StringUtils.isBlank;
import static org.apache.commons.lang3.StringUtils.isNotBlank;

/**
 * Encapsulates the results of validation
 *
 * @see ca.uhn.fhir.validation.FhirValidator
 * @since 0.7
 */
public class ValidationResult {
        public static final int ERROR_DISPLAY_LIMIT_DEFAULT = 1;
        public static final String UNKNOWN = "(unknown)";
        private static final String ourNewLine = System.getProperty("line.separator");
        private final FhirContext myCtx;
        private final boolean myIsSuccessful;
        private final List<SingleValidationMessage> myMessages;
        private int myErrorDisplayLimit = ERROR_DISPLAY_LIMIT_DEFAULT;

        public ValidationResult(FhirContext theCtx, List<SingleValidationMessage> theMessages) {
                boolean successful = true;
                myCtx = theCtx;
                myMessages = theMessages;
                for (SingleValidationMessage next : myMessages) {
                        if (next.getSeverity() == null || next.getSeverity().ordinal() > ResultSeverityEnum.WARNING.ordinal()) {
                                successful = false;
                                break;
                        }
                }
                myIsSuccessful = successful;
        }

        public List<SingleValidationMessage> getMessages() {
                return Collections.unmodifiableList(myMessages);
        }

        /**
         * Was the validation successful (in other words, do we have no issues that are at
         * severity {@link ResultSeverityEnum#ERROR} or {@link ResultSeverityEnum#FATAL}. A validation
         * is still considered successful if it only has issues at level {@link ResultSeverityEnum#WARNING} or
         * lower.
         *
         * @return true if the validation was successful
         */
        public boolean isSuccessful() {
                return myIsSuccessful;
        }

        private String toDescription() {
                if (myMessages.isEmpty()) {
                        return "No issues";
                }

                StringBuilder b = new StringBuilder(100 * myMessages.size());
                int shownMsgQty = Math.min(myErrorDisplayLimit, myMessages.size());

                if (shownMsgQty < myMessages.size()) {
                        b.append("(showing first ")
                                        .append(shownMsgQty)
                                        .append(" messages out of ")
                                        .append(myMessages.size())
                                        .append(" total)")
                                        .append(ourNewLine);
                }

                for (int i = 0; i < shownMsgQty; i++) {
                        SingleValidationMessage nextMsg = myMessages.get(i);
                        b.append(ourNewLine);
                        if (nextMsg.getSeverity() != null) {
                                b.append(nextMsg.getSeverity().name());
                                b.append(" - ");
                        }
                        b.append(nextMsg.getMessage());
                        b.append(" - ");
                        b.append(nextMsg.getLocationString());
                }

                return b.toString();
        }

        /**
         * @deprecated Use {@link #toOperationOutcome()} instead since this method returns a view.
         * {@link #toOperationOutcome()} is identical to this method, but has a more suitable name so this method
         * will be removed at some point.
         */
        @Deprecated
        public IBaseOperationOutcome getOperationOutcome() {
                return toOperationOutcome();
        }

        /**
         * Create an OperationOutcome resource which contains all of the messages found as a result of this validation
         */
        public IBaseOperationOutcome toOperationOutcome() {
                IBaseOperationOutcome oo = (IBaseOperationOutcome)
                                myCtx.getResourceDefinition("OperationOutcome").newInstance();
                populateOperationOutcome(oo);
                return oo;
        }

        /**
         * Populate an operation outcome with the results of the validation
         */
        public void populateOperationOutcome(IBaseOperationOutcome theOperationOutcome) {
                for (SingleValidationMessage next : myMessages) {
                        Integer locationLine = next.getLocationLine();
                        Integer locationCol = next.getLocationCol();
                        String location = next.getLocationString();
                        ResultSeverityEnum issueSeverity = next.getSeverity();
                        String message = next.getMessage();
                        String messageId = next.getMessageId();

                        if (next.getSliceMessages() == null) {
                                addIssueToOperationOutcome(
                                                theOperationOutcome, location, locationLine, locationCol, issueSeverity, message, messageId);
                                continue;
                        }

                        /*
                         * Occasionally the validator will return these lists of "slice messages"
                         * which happen when validating rules associated with a specific slice in
                         * a profile.
                         */
                        for (String nextSliceMessage : next.getSliceMessages()) {
                                String combinedMessage = message + " - " + nextSliceMessage;
                                addIssueToOperationOutcome(
                                                theOperationOutcome,
                                                location,
                                                locationLine,
                                                locationCol,
                                                issueSeverity,
                                                combinedMessage,
                                                messageId);
                        }
                } // for

                if (myMessages.isEmpty()) {
                        String message = myCtx.getLocalizer().getMessage(ValidationResult.class, "noIssuesDetected");
                        OperationOutcomeUtil.addIssue(myCtx, theOperationOutcome, "information", message, null, "informational");
                }
        }

        private void addIssueToOperationOutcome(
                        IBaseOperationOutcome theOperationOutcome,
                        String location,
                        Integer locationLine,
                        Integer locationCol,
                        ResultSeverityEnum issueSeverity,
                        String message,
                        String messageId) {
                if (isBlank(location) && locationLine != null && locationCol != null) {
                        location = "Line[" + locationLine + "] Col[" + locationCol + "]";
                }
                String severity = issueSeverity != null ? issueSeverity.getCode() : null;
                IBase issue = OperationOutcomeUtil.addIssueWithMessageId(
                                myCtx, theOperationOutcome, severity, message, messageId, location, Constants.OO_INFOSTATUS_PROCESSING);

                if (locationLine != null || locationCol != null) {
                        String unknown = UNKNOWN;
                        String line = unknown;
                        if (locationLine != null && locationLine != -1) {
                                line = locationLine.toString();
                        }
                        String col = unknown;
                        if (locationCol != null && locationCol != -1) {
                                col = locationCol.toString();
                        }
                        if (!unknown.equals(line) || !unknown.equals(col)) {
                                OperationOutcomeUtil.addIssueLineExtensionToIssue(myCtx, issue, line);
                                OperationOutcomeUtil.addIssueColExtensionToIssue(myCtx, issue, col);
                                String locationString = "Line[" + line + "] Col[" + col + "]";
                                OperationOutcomeUtil.addLocationToIssue(myCtx, issue, locationString);
                        }
                }

                if (isNotBlank(messageId)) {
                        OperationOutcomeUtil.addMessageIdExtensionToIssue(myCtx, issue, messageId);
                }
        }

        @Override
        public String toString() {
                return "ValidationResult{" + "messageCount=" + myMessages.size() + ", isSuccessful=" + myIsSuccessful
                                + ", description='" + toDescription() + '\'' + '}';
        }

        /**
         * @since 5.5.0
         */
        public FhirContext getContext() {
                return myCtx;
        }

        public int getErrorDisplayLimit() {
                return myErrorDisplayLimit;
        }

        public void setErrorDisplayLimit(int theErrorDisplayLimit) {
                myErrorDisplayLimit = theErrorDisplayLimit;
        }
}