import Foundation
import CoreGraphics
import CoreText

//
//  Created by Mike Griebling on 2022-12-31.
//  Translated from an Objective-C implementation by Kostub Deshmukh.
//
//  This software may be modified and distributed under the terms of the
//  MIT license. See the LICENSE file for details.
//

public class MTFont {
    
    var defaultCGFont: CGFont!
    var ctFont: CTFont!
    var mathTable: MTFontMathTable?
    var rawMathTable: NSDictionary?
    
    init() {}
    
    /// `MTFont(fontWithName:)` does not load the complete math font, it only has about half the glyphs of the full math font.
    /// In particular it does not have the math italic characters which breaks our variable rendering.
    /// So we first load a CGFont from the file and then convert it to a CTFont.
    convenience init(fontWithName name: String, size:CGFloat) {
        self.init()
        print("Loading font \(name)")
        let bundle = MTFont.fontBundle
        let fontPath = bundle.path(forResource: name, ofType: "otf")
        let fontDataProvider = CGDataProvider(filename: fontPath!)
        self.defaultCGFont = CGFont(fontDataProvider!)!
        print("Num glyphs: \(self.defaultCGFont.numberOfGlyphs)")
        
        self.ctFont = CTFontCreateWithGraphicsFont(self.defaultCGFont, size, nil, nil);
        
        print("Loading associated .plist")
        let mathTablePlist = bundle.url(forResource:name, withExtension:"plist")
        self.rawMathTable = NSDictionary(contentsOf: mathTablePlist!)
        self.mathTable = MTFontMathTable(withFont:self, mathTable:rawMathTable!)
    }
    
    static var fontBundle:Bundle {
        // Uses bundle for class so that this can be access by the unit tests.
        Bundle(url: Bundle.module.url(forResource: "mathFonts", withExtension: "bundle")!)!
    }
    
    /** Returns a copy of this font but with a different size. */
    public func copy(withSize size: CGFloat) -> MTFont {
        let newFont = MTFont()
        newFont.defaultCGFont = self.defaultCGFont
        newFont.ctFont = CTFontCreateWithGraphicsFont(self.defaultCGFont, size, nil, nil)
        newFont.rawMathTable = self.rawMathTable
        newFont.mathTable = MTFontMathTable(withFont: newFont, mathTable: newFont.rawMathTable!)
        return newFont
    }
    
    func get(nameForGlyph glyph:CGGlyph) -> String {
        let name = defaultCGFont.name(for: glyph) as? String
        return name ?? ""
    }
    
    func get(glyphWithName name:String) -> CGGlyph {
        defaultCGFont.getGlyphWithGlyphName(name: name as CFString)
    }
    
    /** The size of this font in points. */
    public var fontSize:CGFloat { CTFontGetSize(self.ctFont) }
    
}