extern crate serde_json;
extern crate tokio;
extern crate tokio_postgres;
use std::fs::File;
mod configure;
mod parser;
mod serializer;
use rayon::prelude::*;
use std::collections::HashMap;
use std::fs;
use std::io::prelude::*;
use tokio_postgres::types::ToSql;
use tokio_postgres::{Error, NoTls};

const PCAPNG_SIGNATURE: [u8; 4] = [0x0a, 0x0d, 0x0d, 0x0a];
const PCAP_SIGNATURE: [u8; 4] = [0xed, 0xab, 0xee, 0xdb];

fn query_string(insert_max: &usize) -> String {
   
    // Changed this to String with given capacity after stumbling over https://github.com/hoodie/concatenation_benchmarks-rs
    // Impressive performance increase! 
    let mut insert_template = String::with_capacity(insert_max * 8 + 43);
    insert_template.push_str("INSERT INTO json_dump (packet) Values ");

    for insert in 0..insert_max - 1 {
        insert_template.push_str(&(format!("(${}), ", insert + 1)));
    }
    insert_template.push_str(&(format!("(${})", insert_max)));

    insert_template
}

fn smallest_prime_divisor(remainder: usize ) -> usize {
    let smallest_divisor: usize = (2..(remainder/2)).into_par_iter().find_first(|x| remainder % x == 0).unwrap();
    smallest_divisor
}

#[tokio::main(core_threads = 4)] // By default, tokio_postgres uses the tokio crate as its runtime.
async fn main() -> Result<(), Error> {
    /* Init values from file */

    let config: configure::Config = configure::from_json_file().unwrap();

    // let mut pcap_map: Hashmap<std::path::Path, bool> = HashMap::new();

    // TODO: hash file metadata, so its state is comparable at different times and can be written to a db table
    //       This db table should include UUIDs so it can be joined effectively
    let mut pcap_map = HashMap::new();
    if let Ok(entries) = fs::read_dir(config.pcap_dir) {
        for entry in entries {
            if let Ok(entry) = entry {
                if let Ok(_file_type) = entry.file_type() {
                    if entry.metadata().unwrap().is_file() {
                        let mut magic_number: [u8; 4] = [0; 4];
                        let _signature = File::open(entry.path().to_owned())
                            .unwrap()
                            .read_exact(&mut magic_number)
                            .unwrap();
                        match magic_number {
                            PCAPNG_SIGNATURE => pcap_map.insert(entry.path(), entry.metadata()),
                            PCAP_SIGNATURE => pcap_map.insert(entry.path(), entry.metadata()),
                            _ => None,
                        };
                        // println!("{:?}", &entry.metadata().unwrap().modified());
                    }
                } else {
                    println!("Couldn't get file type for {:?}", entry.path());
                }
            }
        }
    }
    println!("{:?}", pcap_map.iter());
    /* db connection */
    let (client, connection) = tokio_postgres::connect(&config.connection, NoTls).await?;

    tokio::spawn(async move {
        if let Err(e) = connection.await {
            eprintln!("connection error: {}", e);
        }
    });

    client
        .execute("DROP TABLE IF EXISTS json_dump", &[])
        .await?;
    client
        .execute(
            "CREATE TABLE json_dump ( ID serial NOT NULL PRIMARY KEY, packet json NOT NULL)",
            &[],
        )
        .await?;

    /* device or file input */
    
    match config.is_device {
    false => for _pcap_file in pcap_map.keys() {

        // TODO: Tuning vector capacity according to actuarial excpectation,  mean average & std dev of packet size
        let v: Vec<parser::QryData> = parser::parse(&_pcap_file, &config.filter);
        //let mut v = Vec::<parser::QryData>::with_capacity(35536);
        //v.extend(parser::parse(&_pcap_file, &config.filter));

        let packets_serialized = serializer::serialize_packets(v);
        //let mut packets_serialized = Vec::<serde_json::Value>::with_capacity(35536);
        //packets_serialized.extend(serializer::serialize_packets(v));

        /* Query */
        
        let chunk_count = packets_serialized.len() / config.insert_max;
        let remainder: usize = packets_serialized.len() % config.insert_max;
        let chunker = &packets_serialized.len() < &config.insert_max;
        match chunker {
            true => {
                let insert_str = query_string(&packets_serialized.len());
                let statement_false = client.prepare(&insert_str).await?;
                client
                    .query_raw(
                        &statement_false,
                        packets_serialized.iter().map(|p| p as &dyn ToSql),
                    )
                    .await?;
            }

            false => {
                let insert_str = query_string(&config.insert_max);
                let statement = client.prepare(&insert_str).await?;
                
                for _i in 0..chunk_count {
                    let (_input, _) = packets_serialized.split_at(config.insert_max);
                    client
                        .query_raw(&statement, _input.to_vec().iter().map(|p| p as &dyn ToSql))
                        .await?;
                }

                println!("Packets, total:{:?}", packets_serialized.len());
                println!("Chunks, total:{}", chunk_count);
                println!("Chunks, remainder:{}", remainder);

                if remainder > 0 {          
                    let rem_str = query_string(&remainder);
                    let statement_remainder = client.prepare(&rem_str).await?;
                    let (_garbage, _input) =
                        packets_serialized.split_at(packets_serialized.len() - remainder);
                    client
                        .query_raw(
                            &statement_remainder,
                            _input.to_vec().iter().map(|p| p as &dyn ToSql),
                        )
                        .await?;
                }
            }
        }
    }
    , 
    true => {
        let insert_str = query_string(&config.insert_max);
        let statement = client.prepare(&insert_str).await?;
        loop {
            let v: Vec<parser::QryData> = parser::parse_device(&config.device, &config.filter, &config.insert_max);
            let packets_serialized = serializer::serialize_packets(v);
            client
                .query_raw(
                    &statement,
                    packets_serialized.iter().map(|p| p as &dyn ToSql),
                )
                .await?;
        }
    },
   } 
   Ok(())
}