use chrono::Local;
use clap::Parser;
use serialport::DataBits;
use serialport::Parity;
use serialport::StopBits;
use std::error::Error;
use std::fs::OpenOptions;
use std::io::ErrorKind;
use std::io::Write;
use std::thread::sleep;
use std::time::Duration;

/// Command-line arguments using Clap.
#[derive(Parser, Debug)]
#[command(author, version, about = "ASMR: Automatic S-Meter Reader")]
struct Cli {
    /// COM port
    #[arg(short = 'c', long)]
    com: Option<String>,

    /// Format
    #[arg(short = 'o', long,)]
    file: Option<String>,

    /// Frequency
    #[arg(short = 'f', long)]
    freq: Option<u32>,

    /// Seconds to wait between measurements
    #[arg(short = 'w', long, default_value = "5")]
    wait: Option<u16>,
}

// Read S-meter
fn get_smeter(comport: &str) -> String {
    let mut port = serialport::new(comport, 4800)
        .data_bits(DataBits::Eight)
        .stop_bits(StopBits::Two)
        .parity(Parity::None)
        .timeout(Duration::from_millis(100))
        .open()
        .expect("Failed to open port");

    // Duh, you need the ";" on the end!
    // let output = "FA14075000;"; // set VFO A frequency
    //  let output = "FA;"; // ask for VFO A frequency
    let output = "SM;"; // ask for S-meter reading
    // What are we actually sending?
    //dbg!(output.as_bytes());

    match port.write(output.as_bytes()) {
        Ok(_) => {
            std::io::stdout().flush().unwrap();
        }
        Err(ref e) if e.kind() == ErrorKind::TimedOut => (),
        Err(e) => eprintln!("{:?}", e),
    }

    // Sleep to allow the device to switch from read to write.
    // Otherwise we can lose some bytes on read.
    sleep(Duration::from_millis(50));

    let mut buf = [0u8; 1024];
    loop {
        match port.read(&mut buf) {
            Ok(n) => {
                let data = String::from_utf8_lossy(&buf[..n]).to_string();
                //dbg!(data.as_bytes());
                //let value = data;
                // For S-meter, just take the numbers
                let value = &data[2..5];
                return format!("{}", value);
                // return;
            }
            Err(_) => {} // lol that I can just not put a return in?
        }
    }
}

// Set frequency
fn set_freq(comport: &str, freq: u32) -> String {
    let mut port = serialport::new(comport, 4800)
        .data_bits(DataBits::Eight)
        .stop_bits(StopBits::Two)
        .parity(Parity::None)
        .timeout(Duration::from_millis(100))
        .open()
        .expect("Failed to open port");

    // Duh, you need the ";" on the end!
    //let output = "FA14075000;"; // set VFO A frequency
    let output = format!("FA{};", freq);
    //println!("{output}");

    match port.write(output.as_bytes()) {
        Ok(_) => {
            std::io::stdout().flush().unwrap();
        }
        Err(ref e) if e.kind() == ErrorKind::TimedOut => (),
        Err(e) => eprintln!("{:?}", e),
    }

    let mut buf = [0u8; 1024];
    match port.read(&mut buf) {
        Ok(_) => {
            return format!("Frequency set.");
        }
        Err(_) => {
            return format!("Failed to set frequency.");
        }
    }
}

// Write row to a file
fn write_row(str_arr: [String; 5], file: &String, fmt: &str) -> Result<(), Box<dyn Error>> {
    // From https://docs.rs/csv/latest/csv/tutorial/index.html#writing-csv
    if fmt == "csv" {
        let file = OpenOptions::new()
            .write(true)
            .create(true)
            .append(true)
            .open(file)
            .unwrap();
        let mut wtr = csv::Writer::from_writer(file);

        // Since we're writing records manually, we must explicitly write our
        // header record. A header record is written the same way that other
        // records are written.
        // wtr.write_record(["City", "State", "Population", "Latitude", "Longitude"])?;
        let _ = wtr.write_record(str_arr);

        // A CSV writer maintains an internal buffer, so it's important
        // to flush the buffer when you're done.
        wtr.flush()?;
        Ok(())
    } else {
        println!("Only accepts csv format for now, not recording to file.");
        Ok(())
    }
}

// Main funtion
fn main() {
    // Arguments
    let cli = Cli::parse();

    let com = match cli.com {
        Some(com) => com,
        None => {
            // https://github.com/serialport/serialport-rs#listing-available-ports
            let ports = serialport::available_ports().expect("No ports found!");
            println!("Available Ports:");
            for p in ports {
                println!("{}", p.port_name);
            }
            println!("\nMissing `-c` port argument, use one listed above.");
            return;
        } //todo!()
    };

    let file_out = match cli.file {
        Some(file_out) => {
            println!("Saving results to {}", file_out);
            file_out
        },
        None => {
            println!("Not saving results. Use `-o file.csv` to save to a file.");
            "no file".to_string()
        } //todo!()
    };

    let frequency = match cli.freq {
        Some(frequency) => frequency,
        None => {
            return;
        } //todo!()
    };

    let wait: u16 = match cli.wait {
        Some(wait) => wait,
        None => {
            return;
        } //todo!()
    };

    // Set the requested frequency
    set_freq(&com, frequency);

    println!("Press Ctrl + C to quit.");

    // Simple test loop to make sure we are getting values each time
    //for _i in 1..11 {
    loop {
        // Get datestamp
        let date = Local::now();
        // Get S-meter
        let s_val = get_smeter(&com);
        //println!("{a}");
        match s_val.parse::<i32>() {
            // Simple graph as we go. Eventually this will be replaced.
            Ok(n) => println!(
                "{} {} {}",
                date.format("%Y-%m-%d %H:%M:%S").to_string(),
                s_val,
                "#".repeat(n.try_into().unwrap())
            ),
            Err(_e) => todo!(),
        }
        // If they provided a file name
        if file_out != "no file" {
            if let Err(err) = write_row(
                [
                    date.format("%Y-%m-%d %H:%M:%S").to_string(),
                    frequency.to_string(),
                    "lat".to_string(),
                    "lon".to_string(),
                    s_val.to_string(),
                ],
                &file_out,
                "csv",
            ) {
                println!("{}", err);
            }
        }
        sleep(Duration::from_millis(wait as u64 * 1000));
    }
}