//
//  FileReader.swift
//  PrySDR
//
//  Created by Jacky Jack on 06/01/2025.
//

import Foundation

enum FileReaderError: Error {
    case noFile
    case readError
    case noData
    case seekError
}

class FileReader {
    
    var filepath: String?
    let filemgr = FileManager.default
    var fileHandle: FileHandle?
    
    init() {
        
    }
    
    func open(filename: String) throws {
        let dir = getCurrentExecutableDir()
        
        print(dir+"/"+filename)
        if !filemgr.fileExists(atPath: filename) {
            print("Cant find file \(filename)")
            throw FileReaderError.noFile
        }

        fileHandle = FileHandle(forReadingAtPath: dir+"/"+filename)
        if (fileHandle == nil) {
            print("FileHandler failed")
        }
    }
    
    func readBuffer(_ count: Int) -> [UInt8] {
        print("FileReader not implemented")
        return []
    }
    
    func readBuffer(_ count: Int) -> [Int8] {
        print("FileReader not implemented")
        return []
    }
    
    func readBuffer(_ count: Int) -> [UInt16] {
        print("FileReader not implemented")
        return []
    }
    
    func readBuffer(_ count: Int) -> [Int16] {
        print("FileReader not implemented")
        return []
    }
    
    func readBuffer(_ count: Int) -> [Float] {
        print("FileReader not implemented")
        return []
    }
    
    func readAllUInt8() throws -> [UInt8] {
        var ret_arr:[UInt8]? = nil
        if let file = fileHandle {
            do {
                if let databuf = try file.readToEnd() {
                    //print("read \(databuf.count) \(databuf) bytes")
                    //let temp_arr = [Int8](databuf)
                    ret_arr = [UInt8](repeating: 0, count: databuf.count)
                    for i in 0..<ret_arr!.count {
                        //print(String(format:"%02X", databuf[i]),terminator: "")
                        //convert from 0..255 to -127..128, from UInt8->Int8
                        ret_arr![i] = databuf[i]
                    }
                }
            } catch {
                print("ReadAll u8 error:\(error)")
                throw FileReaderError.readError
            }
        }
        if ret_arr == nil {
            return []
        } else {
            return ret_arr!
        }
    }
    
    func readAllInt8() throws -> [Int8] {
        var ret_arr:[Int8]? = nil
        if let file = fileHandle {
            do {
                if let databuf = try file.readToEnd() {
                    //print("read \(databuf.count) \(databuf) bytes")
                    //let temp_arr = [Int8](databuf)
                    ret_arr = [Int8](repeating: 0, count: databuf.count)
                    for i in 0..<ret_arr!.count {
                        //print(String(format:"%02X", databuf[i]),terminator: "")
                        //convert from 0..255 to -127..128, from UInt8->Int8
                        let val = databuf[i]
                        if val <= 127 {
                            ret_arr![i] = Int8(val)-127
                        } else {
                            ret_arr![i] = Int8(val-128)
                        }
                        //print(String(format:"%02X", i8_arr![i]),terminator: "")
                    }
                }
            } catch {
                print("ReadAll i8 error:\(error)")
                throw FileReaderError.readError
            }
        }
        if ret_arr == nil {
            return []
        } else {
            return ret_arr!
        }
    }
    
    //https://forums.swift.org/t/swift-5-read-binary-file-problem-with-unsafe-mutable-pointers/31048/6
    func readAllInt16() throws -> [Int16] {
        var ret_arr:[Int16]? = nil
        if let file = fileHandle {
            do {
                if let databuf = try file.readToEnd() {
                    ret_arr = [Int16](asInt16(databuf))
                }
                print(ret_arr![0],ret_arr![1],ret_arr![2],ret_arr![3])
            } catch {
                print("ReadAll i8 error:\(error)")
                throw FileReaderError.readError
            }
        }
        if ret_arr == nil {
            return []
        } else {
            return ret_arr!
        }
    }
    
    func readAllUInt16() throws -> [UInt16] {
        var ret_arr:[UInt16]? = nil
        if let file = fileHandle {
            do {
                if let databuf = try file.readToEnd() {
                    ret_arr = [UInt16](asUInt16(databuf))
                }
            } catch {
                print("ReadAll i8 error:\(error)")
                throw FileReaderError.readError
            }
        }
        if ret_arr == nil {
            return []
        } else {
            return ret_arr!
        }
    }
    
    func readAll() throws -> [Float] {
        print("FileReader not implemented")
        return []
    }
    
    func seek(toFileOffset: UInt64) throws {
        if let file = self.fileHandle {
            file.seek(toFileOffset: toFileOffset)
        }
    }
    
    
    
    func close() {
        fileHandle?.closeFile()
    }
    
}