import AppKit
import SwiftUI

@main
struct SpreadsheetLayoutTests {
    @MainActor static func main() throws {
        let source = URL(fileURLWithPath: CommandLine.arguments[1])
        let layout = try JSONDecoder().decode(SpreadsheetLayout.self, from: Data(contentsOf: source)).validated()
        let sheet = layout.sheets[0]
        let narrow = SpreadsheetZoom.width.scale(sheet: sheet, viewport: CGSize(width: 800, height: 500))
        let wide = SpreadsheetZoom.width.scale(sheet: sheet, viewport: CGSize(width: 1800, height: 900))
        precondition(narrow * sheet.width <= 752)
        precondition(wide == 1)
        let page = SpreadsheetZoom.page.scale(sheet: sheet, viewport: CGSize(width: 800, height: 500))
        precondition(page * sheet.height <= 452)
        precondition(SpreadsheetZoom.actual.scale(sheet: sheet, viewport: .zero) == 1)
        precondition(sheet.cells.first { $0.reference == "H30" }?.style.rotation == 255)
        precondition(sheet.cells.first { $0.reference == "C25" }?.text == "001234567890")
        precondition(sheet.cells.first { $0.reference == "F27" }?.text.trimmingCharacters(in: .whitespaces) == "544.30")
        let signature = sheet.cells.first { $0.reference == "A30" }!
        precondition(signature.textClip.width > signature.width)
        print("Workbook layout, zoom bounds, vertical text and exact values passed")
        if CommandLine.arguments.count > 2 {
            let folder = URL(fileURLWithPath: CommandLine.arguments[2], isDirectory: true)
            try FileManager.default.createDirectory(at: folder, withIntermediateDirectories: true)
            _ = NSApplication.shared
            NSApplication.shared.appearance = NSAppearance(named: .aqua)
            let canvas = SpreadsheetCanvasView(sheet: sheet, scale: 1)
            try capture(canvas, to: folder.appendingPathComponent("sheet.png"))
            for size in [CGSize(width: 1080, height: 620), CGSize(width: 820, height: 480)] {
                let host = NSHostingView(rootView: ExpenseSpreadsheetPreview(layout: layout))
                host.frame = NSRect(origin: .zero, size: size)
                let window = NSWindow(contentRect: host.frame, styleMask: [.borderless], backing: .buffered, defer: false)
                window.contentView = host
                host.layoutSubtreeIfNeeded()
                RunLoop.current.run(until: Date().addingTimeInterval(0.5))
                try capture(host, to: folder.appendingPathComponent("preview-\(Int(size.width)).png"))
                window.orderOut(nil)
            }
            print("Native preview snapshots written to \(folder.path)")
        }
    }

    @MainActor static func capture(_ view: NSView, to file: URL) throws {
        guard let bitmap = view.bitmapImageRepForCachingDisplay(in: view.bounds) else {
            throw ExpenseTemplateFailure.message("Cannot create preview snapshot")
        }
        view.cacheDisplay(in: view.bounds, to: bitmap)
        guard let png = bitmap.representation(using: .png, properties: [:]) else {
            throw ExpenseTemplateFailure.message("Cannot encode preview snapshot")
        }
        try png.write(to: file)
    }
}