main.rs

// SPDX-FileCopyrightText: 2024 Phil Höfer <phil@suma-ev.de>
// SPDX-License-Identifier: AGPL-3.0-only

use core::str;
use std::collections::HashMap;
use std::fs::File;
use std::io::{self, BufRead, BufReader};
use std::error::Error;
use std::str::FromStr;
use std::fs;

use predictors::basic_set::SetPredictor;
use toml::Table;

use csv::ReaderBuilder;


use tiny_http::{Server, Response};

mod predictors;
use predictors::{basic_markov,basic_set, Predictor};
use predictors::basic_markov::MarkovChain;

use postgres::{Client, NoTls};


fn main() -> Result<(), io::Error> {

    let mut last_update = std::time::SystemTime::now();
    let config_toml = read_config("data/config.toml").or(read_config("config.toml")).unwrap().parse::<Table>().unwrap();
    let mut config = HashMap::new();
    for (key, value) in config_toml {
        match value {
            toml::Value::String(s) => {
                config.insert(key, s);
            }
            toml::Value::Integer(i) => {
                config.insert(key, i.to_string());
            }
            _ => {
                // Ignore other types
            }
        }
    }


    let mut markov_chain = basic_set::from_file_path_and_config(
        vec!["../../data/data.csv","data/data.csv","data.csv","data_full.csv"],config.clone())
                .unwrap_or(basic_set::SetPredictor::new());

    markov_chain = read_from_db(config.clone(), markov_chain);
    markov_chain.decay();

    // let term_frequency_threshold = match config.get("term_frequency_threshold") {
    //     Some(toml::Value::Integer(n)) if *n >= 0 => *n as usize,
    //     _ => 2
    // };
    //let filtered_markov_chain = filter_markov_chain(&markov_chain,term_frequency_threshold);

    // Print the Markov Chain for verification
    // for (key, values) in &markov_chain {
    //      //println!("{}: {:?}", key, values);
    // }

    // Test the function
    let word = "wie"; // replace with the word you want to check
    let top_words = &markov_chain.predict(&word, 3);
    println!("Example prediction for '{}': {:?}", word, top_words);



    let server = Server::http("0.0.0.0:8000").unwrap();

    for request in server.incoming_requests() {
        //   println!("received request! method: {:?}, url: {:?}, headers: {:?}",
        //       request.method(),
        //       request.url(),
        //       request.headers()
        //   );
        match config.get("auth") { 
            Some(server_auth) => {
                match get_authkey(request.url().clone()) {
                    Ok(client_auth) => {
                        if client_auth != server_auth.clone() {
                            println!("invalid auth:{}, server auth: {}", client_auth, server_auth);
                            request.respond(Response::from_string(""));
                            continue;
                        }
                    },
                    _ => {}
                }
            },
            _ => {}
        }
        let query = get_query(request.url());
        //println!("got query:{}", query.clone().unwrap());
        match query {
            Ok(query) => {
                let predict_count = match config.get("max_predict_count") {
                    Some(n) if n.parse::<usize>().unwrap_or_default() > 0 => n.parse::<usize>().unwrap_or(5),
                    _ => 5
                };
                let prediction = &markov_chain.predict(&query, predict_count);
                //println!("Query: {}, Prediction:{}", query, prediction);
                let response = Response::from_string(prediction);
                request.respond(response);
                let now = std::time::SystemTime::now();
                let elapsed = now.duration_since(last_update).expect("Time went backwards");
                if elapsed >= std::time::Duration::from_secs(24 * 60 * 60) {
                    markov_chain.decay();
                    markov_chain = read_from_db(config.clone(), markov_chain);
                    last_update = now;
                }
            },
            Err(e) => {
                //println!("Error: {}",e);
            }
        }
    }

    Ok(())
}


fn read_from_db(config: HashMap<String, String>, mut predictor: SetPredictor) -> SetPredictor {
    let default_password = &String::from("");
    match (config.get("db_host"), config.get("db_password")) {
        (Some(db_host), Some(db_password)) => {
            let mut client = Client::connect(format!("host={} user=metager password={} dbname=postgres",db_host, db_password).as_str(), NoTls);
            match client {
                Ok(mut c) => {
                    let mut count = 0;
                    match c.query("SELECT query FROM public.logs_partitioned ORDER BY time DESC LIMIT 100000", &[]) {
                        Ok(rows) => {
                            for row in rows {
                                let query: &str = row.get(0);
                                predictor.update(query);
                                count += 1;
                            }
                            println!("{} queries read from DB", count);
                            predictor
                        },
                        Err(e) => {
                            println!("Error while reading from DB: {}", e);
                            predictor
                        }
                    }
                },
                Err(e) => {
                    println!("Error while connecting to DB: {}", e);
                    predictor
                }
            }
        },
        _ => {
            println!("No DB config found. Skipping...");
            predictor
        }
    }  

} 

fn read_config(file_path: &str) -> Result<String, io::Error> {
    fs::read_to_string(file_path)
}

//TODO: unify get_X() functions
fn get_query(request_url: &str) -> Result<String, url::ParseError> {
    let parsed_url = request_url.split_once('?').map_or(request_url, |(_, after)| after);
    //println!("parsed_url:{}", parsed_url);
    let query_pairs = url::form_urlencoded::parse(parsed_url.as_bytes());
    for (key, value) in query_pairs {
        //println!("key:{}, value: {}", key, value);
        if key == "q" {
            return Ok(value.into_owned());
        }
    }
    Ok(String::from_str("").unwrap())
}
fn get_authkey(request_url: &str) -> Result<String, url::ParseError> {
    let parsed_url = request_url.split_once('?').map_or(request_url, |(_, after)| after);
    //println!("parsed_url:{}", parsed_url);
    let query_pairs = url::form_urlencoded::parse(parsed_url.as_bytes());
    for (key, value) in query_pairs {
        //println!("key:{}, value: {}", key, value);
        if key == "auth" {
            return Ok(value.into_owned());
        }
    }
    Ok(String::from_str("").unwrap())
}


fn filter_markov_chain(markov_chain: &MarkovChain, min_count: usize) -> MarkovChain {
    let mut filtered_chain: MarkovChain = HashMap::new();

    for (key, followers) in markov_chain {
        let filtered_followers: HashMap<String, usize> = followers
            .iter()
            .filter(|&(_, &count)| count >= min_count)
            .map(|(word, &count)| (word.clone(), count))
            .collect();

        if !filtered_followers.is_empty() {
            filtered_chain.insert(key.clone(), filtered_followers);
        }
    }

    filtered_chain
}