// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//


#if DEPLOYMENT_RUNTIME_OBJC || os(Linux)
    import Foundation
    import XCTest
#else
    import SwiftFoundation
    import SwiftXCTest
#endif

enum XMLParserDelegateEvent {
    case startDocument
    case endDocument
    case didStartElement(String, String?, String?, [String: String])
    case didEndElement(String, String?, String?)
    case foundCharacters(String)
}

extension XMLParserDelegateEvent: Equatable {

    public static func ==(lhs: XMLParserDelegateEvent, rhs: XMLParserDelegateEvent) -> Bool {
        switch (lhs, rhs) {
        case (.startDocument, startDocument):
            return true
        case (.endDocument, endDocument):
            return true
        case let (.didStartElement(lhsElement, lhsNamespace, lhsQname, lhsAttr),
                  didStartElement(rhsElement, rhsNamespace, rhsQname, rhsAttr)):
            return lhsElement == rhsElement && lhsNamespace == rhsNamespace && lhsQname == rhsQname && lhsAttr == rhsAttr
        case let (.didEndElement(lhsElement, lhsNamespace, lhsQname),
                  .didEndElement(rhsElement, rhsNamespace, rhsQname)):
            return lhsElement == rhsElement && lhsNamespace == rhsNamespace && lhsQname == rhsQname
        case let (.foundCharacters(lhsChar), .foundCharacters(rhsChar)):
            return lhsChar == rhsChar
        default:
            return false
        }
    }

}

class XMLParserDelegateEventStream: NSObject, XMLParserDelegate {
    var events: [XMLParserDelegateEvent] = []

    func parserDidStartDocument(_ parser: XMLParser) {
        events.append(.startDocument)
    }
    func parserDidEndDocument(_ parser: XMLParser) {
        events.append(.endDocument)
    }
    func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String]) {
        events.append(.didStartElement(elementName, namespaceURI, qName, attributeDict))
    }
    func parser(_ parser: XMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?) {
        events.append(.didEndElement(elementName, namespaceURI, qName))
    }
    func parser(_ parser: XMLParser, foundCharacters string: String) {
        events.append(.foundCharacters(string))
    }
}

class TestXMLParser : XCTestCase {

    static var allTests: [(String, (TestXMLParser) -> () throws -> Void)] {
        return [
            ("test_withData", test_withData),
            ("test_withDataEncodings", test_withDataEncodings),
            ("test_withDataOptions", test_withDataOptions),
        ]
    }

    // Helper method to embed the correct encoding in the XML header
    static func xmlUnderTest(encoding: String.Encoding? = nil) -> String {
        let xmlUnderTest = "<test attribute='value'><foo>bar</foo></test>"
        guard var encoding = encoding?.description else {
            return xmlUnderTest
        }
        if let open = encoding.range(of: "(") {
            let range: Range<String.Index> = open.upperBound..<encoding.endIndex
            encoding = String(encoding[range])
        }
        if let close = encoding.range(of: ")") {
            encoding = String(encoding[..<close.lowerBound])
        }
        return "<?xml version='1.0' encoding='\(encoding.uppercased())' standalone='no'?>\n\(xmlUnderTest)\n"
    }

    static func xmlUnderTestExpectedEvents(namespaces: Bool = false) -> [XMLParserDelegateEvent] {
        let uri: String? = namespaces ? "" : nil
        return [
            .startDocument,
            .didStartElement("test", uri, namespaces ? "test" : nil, ["attribute": "value"]),
            .didStartElement("foo", uri, namespaces ? "foo" : nil, [:]),
            .foundCharacters("bar"),
            .didEndElement("foo", uri, namespaces ? "foo" : nil),
            .didEndElement("test", uri, namespaces ? "test" : nil),
        ]
    }


    func test_withData() {
        let xml = Array(TestXMLParser.xmlUnderTest().utf8CString)
        let data = xml.withUnsafeBufferPointer { (buffer: UnsafeBufferPointer<CChar>) -> Data in
            return buffer.baseAddress!.withMemoryRebound(to: UInt8.self, capacity: buffer.count * MemoryLayout<CChar>.stride) {
                return Data(bytes: $0, count: buffer.count)
            }
        }
        let parser = XMLParser(data: data)
        let stream = XMLParserDelegateEventStream()
        parser.delegate = stream
        let res = parser.parse()
        XCTAssertEqual(stream.events, TestXMLParser.xmlUnderTestExpectedEvents())
        XCTAssertTrue(res)
    }

    func test_withDataEncodings() {
        // If th <?xml header isn't present, any non-UTF8 encodings fail. This appears to be libxml2 behavior.
        // These don't work, it may just be an issue with the `encoding=xxx`.
        //   - .nextstep, .utf32LittleEndian
        let encodings: [String.Encoding] = [.utf16LittleEndian, .utf16BigEndian, .utf32BigEndian, .ascii]
        for encoding in encodings {
            let xml = TestXMLParser.xmlUnderTest(encoding: encoding)
            let parser = XMLParser(data: xml.data(using: encoding)!)
            let stream = XMLParserDelegateEventStream()
            parser.delegate = stream
            let res = parser.parse()
            XCTAssertEqual(stream.events, TestXMLParser.xmlUnderTestExpectedEvents())
            XCTAssertTrue(res)
        }
    }

    func test_withDataOptions() {
        let xml = TestXMLParser.xmlUnderTest()
        let parser = XMLParser(data: xml.data(using: String.Encoding.utf8)!)
        parser.shouldProcessNamespaces = true
        parser.shouldReportNamespacePrefixes = true
        parser.shouldResolveExternalEntities = true
        let stream = XMLParserDelegateEventStream()
        parser.delegate = stream
        let res = parser.parse()
        XCTAssertEqual(stream.events, TestXMLParser.xmlUnderTestExpectedEvents(namespaces: true)  )
        XCTAssertTrue(res)
    }

}