use fpnum::{FPNum, fp};

use integral_geometry::{Point, Rect, Size};

use land2d::Land2D;

use landgen::{

    outline_template::OutlineTemplate,

    template_based::TemplatedLandGenerator,

    LandGenerationParameters,

    LandGenerator,

};

use lfprng::LaggedFibonacciPRNG;

use hwphysics as hwp;

struct GameState {

    land: Land2D<u32>,

    physics: hwp::World,

}

impl GameState {

    fn new(land: Land2D<u32>, physics: hwp::World) -> Self {

        Self {

            land,

            physics,

        }

    }

}

pub struct World {

    random_numbers_gen: LaggedFibonacciPRNG,

    preview: Land2D<u8>,

    game_state: Option<GameState>,

}

impl World {

    pub fn new() -> Self {

        Self {

            random_numbers_gen: LaggedFibonacciPRNG::new(&[]),

            preview: Land2D::new(Size::new(0, 0), 0),

            game_state: None,

        }

    }

    pub fn set_seed(&mut self, seed: &[u8]) {

        self.random_numbers_gen = LaggedFibonacciPRNG::new(seed);

    }

    pub fn preview(&self) -> &Land2D<u8> {

        &self.preview

    }

    pub fn generate_preview(&mut self) {

        fn template() -> OutlineTemplate {

            let mut template = OutlineTemplate::new(Size::new(4096, 2048));

            template.islands = vec![vec![

                Rect::from_size_coords(100, 2050, 1, 1),

                Rect::from_size_coords(100, 500, 400, 1200),

                Rect::from_size_coords(3600, 500, 400, 1200),

                Rect::from_size_coords(3900, 2050, 1, 1),

            ]];

            template.fill_points = vec![Point::new(1, 0)];

            template

        }

        let params = LandGenerationParameters::new(0u8, u8::max_value(), 5, false, false);

        let landgen = TemplatedLandGenerator::new(template());

        self.preview = landgen.generate_land(&params, &mut self.random_numbers_gen);

    }

    pub fn init(&mut self, template: OutlineTemplate) {

        let physics = hwp::World::new(template.size);

        let params = LandGenerationParameters::new(0u32, u32::max_value(), 5, false, false);

        let landgen = TemplatedLandGenerator::new(template);

        let land = landgen.generate_land(&params, &mut self.random_numbers_gen);

        self.game_state = Some(GameState::new(land, physics));

    }

    pub fn step(&mut self) {

        if let Some(ref mut state) = self.game_state {

            state.physics.step(fp!(1), &state.land);

        }

    }

}