use integral_geometry::{Point, Size};

use landgen::{

    wavefront_collapse::generator::{

        TemplateDescription as WfcTemplate,

    },

    LandGenerationParameters, LandGenerator,

};

use lfprng::LaggedFibonacciPRNG;

use mapgen::{theme::Theme, MapGenerator};

use std::fs;

use std::{ffi::CStr, path::Path};

#[repr(C)]

pub struct GameField {

    collision: land2d::Land2D<u16>,

    pixels: land2d::Land2D<u32>,

    landgen_parameters: Option<LandGenerationParameters<u16>>,

}

#[no_mangle]

pub extern "C" fn get_game_field_parameters(

    game_field: &GameField,

    width: *mut i32,

    height: *mut i32,

    play_width: *mut i32,

    play_height: *mut i32,

) {

    unsafe {

        *width = game_field.collision.width() as i32;

        *height = game_field.collision.height() as i32;

        *play_width = game_field.collision.play_width() as i32;

        *play_height = game_field.collision.play_height() as i32;

    }

}

#[no_mangle]

pub extern "C" fn create_empty_game_field(width: u32, height: u32) -> *mut GameField {

    let game_field = Box::new(GameField {

        collision: land2d::Land2D::new(&Size::new(width as usize, height as usize), 0),

        pixels: land2d::Land2D::new(&Size::new(width as usize, height as usize), 0),

        landgen_parameters: None,

    });

    Box::leak(game_field)

}

#[no_mangle]

pub extern "C" fn generate_templated_game_field(

    feature_size: u32,

    seed: *const i8,

    template_type: *const i8,

    data_path: *const i8,

) -> *mut GameField {

    let data_path: &str = unsafe { CStr::from_ptr(data_path) }.to_str().unwrap();

    let data_path = Path::new(&data_path);

    let seed: &str = unsafe { CStr::from_ptr(seed) }.to_str().unwrap();

    let template_type: &str = unsafe { CStr::from_ptr(template_type) }.to_str().unwrap();

    let mut random_numbers_gen = LaggedFibonacciPRNG::new(seed.as_bytes());

    let yaml_templates =

        fs::read_to_string(data_path.join(Path::new("wfc_templates.yaml")).as_path())

            .expect("Error reading map templates file");

    let mut map_gen = MapGenerator::<WfcTemplate>::new();

    map_gen.import_yaml_templates(&yaml_templates);

    let distance_divisor = feature_size.pow(2) / 8 + 10;

    let params = LandGenerationParameters::new(0u16, 0x8000u16, distance_divisor, false, false);

    let template = map_gen

        .get_template(template_type, &mut random_numbers_gen)

        .expect("Error reading templates file")

        .clone();

    let landgen = map_gen.build_generator(template);

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

    let size = collision.size().size();

    let game_field = Box::new(GameField {

        collision,

        pixels: land2d::Land2D::new(&size, 0),

        landgen_parameters: Some(params),

    });

    Box::leak(game_field)

}

#[no_mangle]

pub extern "C" fn apply_theme(

    game_field: &mut GameField,

    data_path: *const i8,

    theme_name: *const i8,

) {

    let data_path: &str = unsafe { CStr::from_ptr(data_path) }.to_str().unwrap();

    let data_path = Path::new(&data_path);

    let theme_name: &str = unsafe { CStr::from_ptr(theme_name) }.to_str().unwrap();

    let map_gen = MapGenerator::<()>::new();

    let theme = Theme::load(

        data_path

            .join(Path::new("Themes"))

            .join(Path::new(theme_name))

            .as_path(),

    )

    .unwrap();

    let params = game_field

        .landgen_parameters

        .expect("Land generator parameters specified");

    let pixels = map_gen.make_texture(&game_field.collision, &params, &theme);

    game_field.pixels = pixels.into();

}

#[no_mangle]

pub extern "C" fn land_get(game_field: &GameField, x: i32, y: i32) -> u16 {

    game_field.collision.get(y, x)

}

#[no_mangle]

pub extern "C" fn land_set(game_field: &mut GameField, x: i32, y: i32, value: u16) {

    game_field.collision.map(y, x, |p| *p = value);

}

#[no_mangle]

pub extern "C" fn land_row(game_field: &mut GameField, row: i32) -> *mut u16 {

    game_field.collision[row as usize].as_mut_ptr()

}

#[no_mangle]

pub extern "C" fn land_fill(

    game_field: &mut GameField,

    x: i32,

    y: i32,

    border_value: u16,

    fill_value: u16,

) {

    game_field

        .collision

        .fill(Point::new(x, y), border_value, fill_value)

}

#[no_mangle]

pub extern "C" fn land_pixel_get(game_field: &GameField, x: i32, y: i32) -> u32 {

    game_field.pixels.get(y, x)

}

#[no_mangle]

pub extern "C" fn land_pixel_set(game_field: &mut GameField, x: i32, y: i32, value: u32) {

    game_field.pixels.map(y, x, |p| *p = value);

}

#[no_mangle]

pub extern "C" fn land_pixel_row(game_field: &mut GameField, row: i32) -> *mut u32 {

    game_field.pixels[row as usize].as_mut_ptr()

}

#[no_mangle]

pub extern "C" fn dispose_game_field(game_field: *mut GameField) {

    unsafe { drop(Box::from_raw(game_field)) };

}