import SwiftUI
import UniformTypeIdentifiers
import AppKit

struct ContentView: View {
    @State private var selectedFileURL: URL?
    @State private var markdownContent: String = ""
    
    var body: some View {
        NavigationSplitView {
            VStack {
                Button("Open Markdown File") {
                    openFile()
                }
                .padding()
                
                Button("Test with Sample Content") {
                    markdownContent = "# Test\n\nThis is **test** content."
                    print("Set test content: \(markdownContent)")
                }
                .padding()
                
                if let url = selectedFileURL {
                    Text("File: \(url.lastPathComponent)")
                        .foregroundColor(.secondary)
                        .font(.caption)
                        .truncationMode(.middle)
                        .padding(.horizontal)
                }
                
                Spacer()
            }
            .frame(minWidth: 200)
            .navigationSplitViewColumnWidth(min: 200, ideal: 250)
        } detail: {
            if !markdownContent.isEmpty {
                MarkdownRenderer(content: markdownContent)
                    .onAppear {
                        print("MarkdownRenderer appeared with content length: \(markdownContent.count)")
                    }
            } else {
                VStack {
                    Image(systemName: "doc.text")
                        .font(.system(size: 60))
                        .foregroundColor(.secondary)
                    Text("Select a markdown file to preview")
                        .foregroundColor(.secondary)
                        .padding()
                }
                .frame(maxWidth: .infinity, maxHeight: .infinity)
            }
        }
        .navigationTitle("Markdown Viewer")
    }
    
    private func openFile() {
        let panel = NSOpenPanel()
        panel.allowsMultipleSelection = false
        panel.canChooseDirectories = false
        panel.canChooseFiles = true
        panel.allowedContentTypes = [UTType.plainText, UTType(filenameExtension: "md")!]
        
        if panel.runModal() == .OK {
            if let url = panel.url {
                selectedFileURL = url
                loadMarkdownFile(from: url)
            }
        }
    }
    
    private func loadMarkdownFile(from url: URL) {
        do {
            let content = try String(contentsOf: url, encoding: .utf8)
            print("File loaded successfully, content length: \(content.count)")
            print("First 100 characters: \(String(content.prefix(100)))")
            markdownContent = content
        } catch {
            print("Error reading file: \(error)")
            markdownContent = "Error loading file: \(error.localizedDescription)"
        }
    }
}

#Preview {
    ContentView()
}