//
//  DataController.swift
//  Nextcloud Cookbook iOS Client
//
//  Created by Vincent Meilinger on 15.09.23.
//

import Foundation
import SwiftUI

class DataStore {
    let fileManager = FileManager.default
    static let shared = DataStore()
    
    private static func fileURL(appending: String) throws -> URL {
        try FileManager.default.url(
            for: .documentDirectory,
            in: .userDomainMask,
            appropriateFor: nil,
            create: false
        )
        .appendingPathComponent(appending)
    }
    
    private static func fileURL() throws -> URL {
        try FileManager.default.url(
            for: .documentDirectory,
            in: .userDomainMask,
            appropriateFor: nil,
            create: false
        )
    }
    
    func load<D: Decodable>(fromPath path: String) async throws -> D? {
        let task = Task<D?, Error> {
            let fileURL = try Self.fileURL(appending: path)
            guard let data = try? Data(contentsOf: fileURL) else {
                return nil
            }
            let decodedData = try JSONDecoder().decode(D.self, from: data)
            return decodedData
        }
        return try await task.value
    }
    
    func loadDynamic(fromPath path: String, type: Decodable.Type) async throws -> Any? {
        let fileURL = try Self.fileURL(appending: path)
        guard let data = try? Data(contentsOf: fileURL) else {
            return nil
        }
        let decoded = try JSONDecoder().decode(type, from: data)
        return decoded
    }
    
    func save<D: Encodable>(data: D, toPath path: String) async {
        let task = Task {
            let data = try JSONEncoder().encode(data)
            let outfile = try Self.fileURL(appending: path)
            try data.write(to: outfile)
        }
        do {
            _ = try await task.value
        } catch {
            print("Could not save data (path: \(path)")
        }
    }
    
    func delete(path: String) {
        Task {
            let fileURL = try Self.fileURL(appending: path)
            try fileManager.removeItem(at: fileURL)
        }
    }
    
    func recipeDetailExists(recipeId: Int) -> Bool {
        let filePath = "recipe\(recipeId).data"
        guard let folderPath = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first?.path() else { return false }
        return fileManager.fileExists(atPath: folderPath + filePath)
    }
    
    func listAllFolders(dir: String) -> [String] {
        guard let baseURL = try? Self.fileURL() else {
            print("Failed to retrieve documents directory.")
            return []
        }

        let targetURL = baseURL.appendingPathComponent(dir)

        do {
            let contents = try fileManager.contentsOfDirectory(at: targetURL, includingPropertiesForKeys: [.isDirectoryKey], options: [.skipsHiddenFiles])
            
            let folders = contents.filter { url in
                (try? url.resourceValues(forKeys: [.isDirectoryKey]).isDirectory) ?? false
            }
            return folders.map { $0.lastPathComponent }
        } catch {
            print("Error listing folders in \(dir): \(error)")
            return []
        }
    }
    
    func clearAll() -> Bool {
        print("Attempting to delete all data ...")
        guard let folderPath = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first?.path() else { return false }
        print("Folder path: ", folderPath)
        do {
            let filePaths = try fileManager.contentsOfDirectory(atPath: folderPath)
            for filePath in filePaths {
                print("File path: ", filePath)
                try fileManager.removeItem(atPath: folderPath + filePath)
            }
        } catch {
            print("Could not delete documents folder contents: \(error)")
            return false
        }
        print("Done.")
        return true
        
    }
}