use db::{LayoutDB, SavedLayout};
use city::{City, House, SIZE};
use itertools::Itertools;
use crate::combine::transpose_layout;

mod city;
mod db;
mod combine;

#[derive(Eq, PartialEq)]
enum LastStep {
    None, Vertical, Horizontal
}

fn main() {
    let mut db = LayoutDB::from_file("layouts.sqlite").expect("Failed to load the DB");
    eprintln!("Loaded the DB, {} stored layouts", db.layouts().len());

    let city = City::read_from_file("01.in");
    eprintln!("Loaded the city file, {} houses", city.get_house_count());

    eprintln!("Building a transposed city...");
    let transposed_city = transpose_city(&city);
    eprintln!("Finished building a transposed city");

    const TOP_LAYOUT_COUNT: usize = 1000;

    let mut cache = combine::CompatibilityCache::new();

    let mut last_improve_step = LastStep::None;
    loop {
        if last_improve_step == LastStep::Vertical { break; }
        eprintln!("Starting to combine {} top houses DB; vertical cuts", TOP_LAYOUT_COUNT);
        let sorted: Vec<SavedLayout> = db.layouts().iter()
            .sorted_by(|x, y| city::get_price(&city, x.houses()).cmp(&city::get_price(&city, y.houses())))
            .map(|layout| (*layout).clone())
            .collect();
        let chosen_layouts: Vec<_> = sorted.into_iter().take(TOP_LAYOUT_COUNT).collect();
        if combine::create_new_best_combination(&city, &chosen_layouts, &chosen_layouts, &mut db, &mut cache, false) {
            last_improve_step = LastStep::Vertical;
        }
        eprintln!("Finished vertical cuts, improvement: {}", last_improve_step == LastStep::Vertical);

        if last_improve_step == LastStep::Horizontal { break; }

        let sorted: Vec<SavedLayout> = db.layouts().iter()
            .sorted_by(|x, y| city::get_price(&city, x.houses()).cmp(&city::get_price(&city, y.houses())))
            .map(|layout| (*layout).clone())
            .collect();
        let chosen_layouts: Vec<_> = sorted.into_iter().take(TOP_LAYOUT_COUNT).collect();
        let transposed_chosen_layouts: Vec<_> = chosen_layouts.iter().map(|x| transpose_saved_layout(x)).collect();

        eprintln!("Starting to combine {} top houses DB; horizontal cuts", TOP_LAYOUT_COUNT);
        if combine::create_new_best_combination(&transposed_city, &transposed_chosen_layouts, &transposed_chosen_layouts, &mut db, &mut cache, true) {
            last_improve_step = LastStep::Horizontal;
        }
        eprintln!("Finished horizontal cuts, improvement: {}", last_improve_step == LastStep::Horizontal);

        if last_improve_step == LastStep::None { break; }
    }
}

fn transpose_city(city: &City) -> City {
    let mut transposed_prices = vec![0u16; SIZE * SIZE];
    for y in 0..SIZE {
        for x in 0..SIZE {
            // Sorry, cache! Not worth optimizing with blocks,
            // this is not going to be ran often.
            transposed_prices[y * SIZE + x] = city.get_price_xy(y, x);
        }
    }

    City::new(transposed_prices)
}

fn transpose_saved_layout(layout: &SavedLayout) -> SavedLayout {
    let mut transposed = Vec::new();
    for house in layout.houses() {
        transposed.push(House::new(house.y, house.x));
    }

    SavedLayout::new(layout.id(), transposed)
}