// Copyright (c) Microsoft Corporation.
// All rights reserved.
//
// This code is licensed under the MIT License.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files(the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions :
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package com.microsoft.aad.adal4j;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

final class ClientDataHttpHeaders {

    public final static String PRODUCT_HEADER_NAME = "x-client-SKU";
    public final static String PRODUCT_HEADER_VALUE = "java";

    public final static String PRODUCT_VERSION_HEADER_NAME = "x-client-VER";
    public final static String PRODUCT_VERSION_HEADER_VALUE = getProductVersion();

    public final static String CPU_HEADER_NAME = "x-client-CPU";
    public final static String CPU_HEADER_VALUE = System.getProperty("os.arch");

    public final static String OS_HEADER_NAME = "x-client-OS";
    public final static String OS_HEADER_VALUE = System.getProperty("os.name");

    public final static String CORRELATION_ID_HEADER_NAME = "client-request-id";
    public final String correlationIdHeaderValue;

    public final static String REQUEST_CORRELATION_ID_IN_RESPONSE_HEADER_NAME = "return-client-request-id";
    public final static String REQUEST_CORRELATION_ID_IN_RESPONSE_HEADER_VALUE = "true";
    private final String headerValues;
    private final Map<String, String> headerMap = new HashMap<String, String>();

    private static String generateCorrelationId(){
    return UUID.randomUUID().toString();
}

    ClientDataHttpHeaders(final String correlationId) {
        if (!StringHelper.isBlank(correlationId)) {
            this.correlationIdHeaderValue = correlationId;
        }
        else {
            this.correlationIdHeaderValue = generateCorrelationId();
        }
        this.headerValues = initHeaderMap();
    }

    private String initHeaderMap() {
        StringBuilder sb = new StringBuilder();
        headerMap.put(PRODUCT_HEADER_NAME, PRODUCT_HEADER_VALUE);
        sb.append(PRODUCT_HEADER_NAME);
        sb.append("=");
        sb.append(PRODUCT_HEADER_VALUE);
        sb.append(";");
        headerMap
                .put(PRODUCT_VERSION_HEADER_NAME, PRODUCT_VERSION_HEADER_VALUE);
        sb.append(PRODUCT_VERSION_HEADER_NAME);
        sb.append("=");
        sb.append(PRODUCT_VERSION_HEADER_VALUE);
        sb.append(";");
        headerMap.put(OS_HEADER_NAME, OS_HEADER_VALUE);
        sb.append(OS_HEADER_NAME);
        sb.append("=");
        sb.append(OS_HEADER_VALUE);
        sb.append(";");
        headerMap.put(CPU_HEADER_NAME, CPU_HEADER_VALUE);
        sb.append(CPU_HEADER_NAME);
        sb.append("=");
        sb.append(CPU_HEADER_VALUE);
        sb.append(";");
        headerMap.put(REQUEST_CORRELATION_ID_IN_RESPONSE_HEADER_NAME,
                REQUEST_CORRELATION_ID_IN_RESPONSE_HEADER_VALUE);
        sb.append(REQUEST_CORRELATION_ID_IN_RESPONSE_HEADER_NAME);
        sb.append("=");
        sb.append(REQUEST_CORRELATION_ID_IN_RESPONSE_HEADER_VALUE);
        sb.append(";");
        headerMap
                .put(CORRELATION_ID_HEADER_NAME, this.correlationIdHeaderValue);
        sb.append(CORRELATION_ID_HEADER_NAME);
        sb.append("=");
        sb.append(this.correlationIdHeaderValue);
        sb.append(";");

        return sb.toString();
    }

    Map<String, String> getReadonlyHeaderMap() {
        return Collections.unmodifiableMap(this.headerMap);
    }

    String getHeaderCorrelationIdValue() {
        return this.correlationIdHeaderValue;
    }

    @Override
    public String toString() {
        return this.headerValues;
    }

    private static String getProductVersion() {
        if (ClientDataHttpHeaders.class.getPackage().getImplementationVersion() == null) {
            return "1.0";
        }
        return ClientDataHttpHeaders.class.getPackage()
                .getImplementationVersion();
    }
}