//
//  AttributedStringConverterTests.swift
//  
//
//  Created by Shadowfacts on 11/24/23.
//

import XCTest
@testable import HTMLStreamer

final class AttributedStringConverterTests: XCTestCase {
    
    #if os(iOS)
    private let font = UIFont.systemFont(ofSize: 13)
    private lazy var italicFont = UIFont(descriptor: font.fontDescriptor.withSymbolicTraits([.traitItalic])!, size: 13)
    private lazy var boldFont = UIFont(descriptor: font.fontDescriptor.withSymbolicTraits([.traitBold])!, size: 13)
    private lazy var boldItalicFont = UIFont(descriptor: font.fontDescriptor.withSymbolicTraits([.traitBold, .traitItalic])!, size: 13)
    private let monospaceFont = UIFont.monospacedSystemFont(ofSize: 13, weight: .regular)
    #elseif os(macOS)
    private let font = NSFont.systemFont(ofSize: 13)
    private lazy var italicFont = NSFont(descriptor: font.fontDescriptor.withSymbolicTraits(.italic), size: 13)!
    private lazy var boldFont = NSFont(descriptor: font.fontDescriptor.withSymbolicTraits(.bold), size: 13)!
    private lazy var boldItalicFont = NSFont(descriptor: font.fontDescriptor.withSymbolicTraits([.bold, .italic]), size: 13)!
    private let monospaceFont = NSFont.monospacedSystemFont(ofSize: 13, weight: .regular)
    #endif
    private let blockquoteParagraphStyle: NSParagraphStyle = {
        let style = NSParagraphStyle.default.mutableCopy() as! NSMutableParagraphStyle
        style.headIndent = 32
        style.firstLineHeadIndent = 32
        return style
    }()
    private let listParagraphStyle: NSParagraphStyle = {
        let style = NSParagraphStyle.default.mutableCopy() as! NSMutableParagraphStyle
        style.headIndent = 32
        style.firstLineHeadIndent = 0
        style.tabStops = [NSTextTab(textAlignment: .right, location: 28), NSTextTab(textAlignment: .natural, location: 32)]
        return style
    }()
    
    private func convert(_ html: String) -> NSAttributedString {
        convert(html, callbacks: DefaultCallbacks.self)
    }
    
    private func convert<Callbacks: AttributedStringCallbacks>(_ html: String, callbacks _: Callbacks.Type = Callbacks.self) -> NSAttributedString {
        let config = AttributedStringConverterConfiguration(
            font: font,
            monospaceFont: monospaceFont,
            color: .black,
            paragraphStyle: .default
        )
        var converter = AttributedStringConverter<Callbacks>(configuration: config)
        return converter.convert(html: html)
    }

    func testConvertBR() {
        XCTAssertEqual(convert("a<br>b"), NSAttributedString(string: "a\nb", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
        XCTAssertEqual(convert("a<br />b"), NSAttributedString(string: "a\nb", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testConvertA() {
        XCTAssertEqual(convert("<a href='https://example.com'>link</a>"), NSAttributedString(string: "link", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
            .link: URL(string: "https://example.com")!,
        ]))
        XCTAssertEqual(convert("<a>link</a>"), NSAttributedString(string: "link", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testConvertP() {
        XCTAssertEqual(convert("<p>a</p><p>b</p>"), NSAttributedString(string: "a\n\nb", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testConvertEm() {
        XCTAssertEqual(convert("<em>hello</em>"), NSAttributedString(string: "hello", attributes: [
            .font: italicFont,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
        XCTAssertEqual(convert("<i>hello</i>"), NSAttributedString(string: "hello", attributes: [
            .font: italicFont,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testConvertStrong() {
        XCTAssertEqual(convert("<strong>hello</strong>"), NSAttributedString(string: "hello", attributes: [
            .font: boldFont,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
        XCTAssertEqual(convert("<b>hello</b>"), NSAttributedString(string: "hello", attributes: [
            .font: boldFont,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testConvertBoldItalic() {
        XCTAssertEqual(convert("<strong><em>hello</em></strong>"), NSAttributedString(string: "hello", attributes: [
            .font: boldItalicFont,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testIncorrectNesting() {
        let result = NSMutableAttributedString()
        result.append(NSAttributedString(string: "bold ", attributes: [
            .font: boldFont,
        ]))
        result.append(NSAttributedString(string: "both", attributes: [
            .font: boldItalicFont,
        ]))
        result.append(NSAttributedString(string: " italic", attributes: [
            .font: italicFont,
        ]))
        result.addAttribute(.paragraphStyle, value: NSParagraphStyle.default, range: NSRange(location: 0, length: result.length))
        XCTAssertEqual(convert("<strong>bold <em>both</strong> italic</em>"), result)
    }
    
    func testMisnestedLink() {
        let result = NSMutableAttributedString()
        result.append(NSAttributedString(string: "hello ", attributes: [
            .link: URL(string: "https://example.com")!,
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
        result.append(NSAttributedString(string: "world", attributes: [
            .link: URL(string: "https://example.com")!,
            .font: boldFont,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
        XCTAssertEqual(convert("<a href='https://example.com'>hello <b>world</a></b>"), result)
    }
    
    func testDel() {
        XCTAssertEqual(convert("<del>blah</del>"), NSAttributedString(string: "blah", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
            .strikethroughStyle: NSUnderlineStyle.single.rawValue,
        ]))
    }
    
    func testCode() {
        XCTAssertEqual(convert("<code>wee</code>"), NSAttributedString(string: "wee", attributes: [
            .font: monospaceFont,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testPre() {
        XCTAssertEqual(convert("<pre>wee</pre>"), NSAttributedString(string: "wee", attributes: [
            .font: monospaceFont,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testBlockquote() {
        XCTAssertEqual(convert("<blockquote>hello</blockquote>"), NSAttributedString(string: "hello", attributes: [
            .font: italicFont,
            .paragraphStyle: blockquoteParagraphStyle,
        ]))
        XCTAssertEqual(convert("<blockquote><b>hello</b></blockquote>"), NSAttributedString(string: "hello", attributes: [
            .font: boldItalicFont,
            .paragraphStyle: blockquoteParagraphStyle,
        ]))
    }
    
    func testTextAfterBlockquote() {
        let result = NSMutableAttributedString()
        result.append(NSAttributedString(string: "wee", attributes: [
            .font: italicFont,
            .paragraphStyle: blockquoteParagraphStyle,
        ]))
        result.append(NSAttributedString(string: "\n\nafter", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
        XCTAssertEqual(convert("<blockquote>wee</blockquote>after"), result)
    }
    
    func testMultipleBlockElements() {
        let result = NSMutableAttributedString()
        result.append(NSAttributedString(string: "a", attributes: [
            .font: italicFont,
            .paragraphStyle: blockquoteParagraphStyle,
        ]))
        result.append(NSAttributedString(string: "\n\n", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
        result.append(NSAttributedString(string: "b", attributes: [
            .font: italicFont,
            .paragraphStyle: blockquoteParagraphStyle,
        ]))
        XCTAssertEqual(convert("<blockquote>a</blockquote><blockquote>b</blockquote>"), result)
    }
    
    func testSelfClosing() {
        XCTAssertEqual(convert("<b />asdf"), NSAttributedString(string: "asdf", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testMakeURLCallback() {
        struct Callbacks: AttributedStringCallbacks {
            static func makeURL(string: String) -> URL? {
                URL(string: "https://apple.com")
            }
        }
        let result = convert("<a href='https://example.com'>test</a>", callbacks: Callbacks.self)
        XCTAssertEqual(result, NSAttributedString(string: "test", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
            .link: URL(string: "https://apple.com")!,
        ]))
    }
    
    func testElementActionCallback() {
        struct Callbacks: AttributedStringCallbacks {
            static func elementAction(name: String, attributes: [Attribute]) -> ElementAction {
                let clazz = attributes.attributeValue(for: "class")
                if clazz == "invisible" {
                    return .skip
                } else if clazz == "ellipsis" {
                    return .replace("…")
                } else {
                    return .default
                }
            }
        }
        let skipped = convert("<span class='invisible'>test</span>", callbacks: Callbacks.self)
        XCTAssertEqual(skipped, NSAttributedString())
        let skipNestped = convert("<span class='invisible'><b>test</b></span>", callbacks: Callbacks.self)
        XCTAssertEqual(skipNestped, NSAttributedString())
        let skipNestped2 = convert("<b><span class='invisible'>test</span></b>", callbacks: Callbacks.self)
        XCTAssertEqual(skipNestped2, NSAttributedString())
        let replaced = convert("<span class='ellipsis'>test</span>", callbacks: Callbacks.self)
        XCTAssertEqual(replaced, NSAttributedString(string: "…", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
    func testOrderedList() {
        let result = convert("<ol><li>a</li><li>b</li></ol>")
        XCTAssertEqual(result, NSAttributedString(string: "\t1.\ta\n\t2.\tb", attributes: [
            .font: font,
            .paragraphStyle: listParagraphStyle,
        ]))
    }
    
    func testMultiScalar() {
        XCTAssertEqual(convert("🇺🇸"), NSAttributedString(string: "🇺🇸", attributes: [
            .font: font,
            .paragraphStyle: NSParagraphStyle.default,
        ]))
    }
    
}