import Foundation
import CoreGraphics

public extension WaveformRenderer {
    /**
      Default styling. Exposed publicly simply because it is re-used internally in the included renderes. May be useful for other
      if other renderes would like to stick to the default behavior.
     */
    func defaultStyle(context: CGContext, with configuration: Waveform.Configuration) {
        // draw pixel-perfect by default
        context.setLineWidth(1.0 / configuration.scale)

        switch configuration.style {
        case let .filled(color):
            context.setFillColor(color.cgColor)
            context.fillPath()

        case let .outlined(color, lineWidth):
            context.setStrokeColor(color.cgColor)
            context.setLineWidth(lineWidth)
            context.setLineCap(.round)
            context.strokePath()

        case let .striped(config):
            context.setLineWidth(config.width)
            context.setLineCap(config.lineCap)
            context.setStrokeColor(config.color.cgColor)
            context.strokePath()

        case let .gradient(colors):
            context.clip()
            let colors = NSArray(array: colors.map { (color: DSColor) -> CGColor in color.cgColor }) as CFArray
            let colorSpace = CGColorSpaceCreateDeviceRGB()
            let gradient = CGGradient(colorsSpace: colorSpace, colors: colors, locations: nil)!
            context.drawLinearGradient(gradient,
                                       start: CGPoint(x: 0, y: 0),
                                       end: CGPoint(x: 0, y: configuration.size.height),
                                       options: .drawsAfterEndLocation)

        case let .gradientOutlined(colors, lineWidth):
            context.setLineWidth(lineWidth)
            context.replacePathWithStrokedPath()
            context.setLineCap(.round)
            context.setLineJoin(.round)
            context.clip()
            let colors = NSArray(array: colors.map { (color: DSColor) -> CGColor in color.cgColor }) as CFArray
            let colorSpace = CGColorSpaceCreateDeviceRGB()
            let gradient = CGGradient(colorsSpace: colorSpace, colors: colors, locations: nil)!
            context.drawLinearGradient(gradient,
                                       start: CGPoint(x: 0, y: 0),
                                       end: CGPoint(x: 0, y: configuration.size.height),
                                       options: .drawsAfterEndLocation)

        case let .spectralTint(low, _):
            // `defaultStyle` is the fallback path for renderers that don't implement spectral drawing
            // themselves — they pass us a normal envelope path and we fill it with the `low` color.
            // `LinearWaveformRenderer.render` overrides this for proper per-column tinting.
            context.setFillColor(low.cgColor)
            context.fillPath()
        }
    }
}