mod generator;
pub mod chunk;
pub mod block;
use std::time::Instant;
use linked_hash_map::LinkedHashMap;
use std::path::PathBuf;
use std::path::Path;
use std::io::Write;
use std::io::Read;
use std::fs;
use cgmath::{Point3, InnerSpace};
use std::collections::HashMap;
use generator::WorldGen;
use chunk::WorldChunk;
use block::WorldBlock;
use yaml_rust::{Yaml, YamlLoader, YamlEmitter};


pub struct World {
    name: String,
    chunks: HashMap<Point3<u32>, WorldChunk>,
}

impl World {

    pub fn new(name: String) -> Self {
        Self { 
            name, 
            chunks: HashMap::new(),
        }
    }

    pub fn all_blocks(&self) -> Vec<(Point3<u32>, &WorldBlock)> {
        self.chunks.iter().map(|(chunk_pos, chunk)| {
            let off = chunk_pos * chunk::SIZE as u32;
            let result: Vec<(Point3<u32>, &WorldBlock)> = chunk.all_blocks().iter().map(|(pos, block)| {
                (
                    Point3{x: off.x+pos.x, y: off.y+pos.y, z: off.z+pos.z},
                    *block
                )
            }).collect();
            result
        }).flatten().collect()
    }

    pub fn save(&self) {
        // Get directory
        let mut dir = dirs::data_local_dir().unwrap();
        dir.push("Voxelgame");
        fs::create_dir_all(&dir).expect("Failed to create directory");

        // Save all chunks
        for (pos, chunk) in self.chunks.iter() {
            let bytes = chunk.to_bytes();
            let filename = format!("chunk_{}_{}_{}.dat", pos.x, pos.y, pos.z);
            let path: PathBuf = [dir.to_str().unwrap(), &filename].iter().collect();
            
            let mut file = fs::File::create(path).expect("Failed to create file");
            file.write(&bytes).unwrap();
        }

        // Save metadata
        let mut data: LinkedHashMap<Yaml, Yaml> = LinkedHashMap::new();
        data.insert(Yaml::String("name".to_string()), Yaml::String(self.name.clone()));
        
        let mut data_str = String::new();
        let mut emit = YamlEmitter::new(&mut data_str);
        emit.dump(&Yaml::Hash(data)).expect("Failed to encode yaml");

        let data_path: PathBuf = [dir.to_str().unwrap(), "world.yml"].iter().collect();
        let mut data_file = fs::File::create(data_path).unwrap();
        data_file.write_all(data_str.as_bytes()).expect("Failed to write");
    }

    pub fn load(&mut self) {
        // Get directory
        let mut dir = dirs::data_local_dir().unwrap();
        dir.push("Voxelgame");
        if !dir.is_dir() {
            println!("Not exists: {:?}", dir);
            return; 
        }

        // Load all chunks
        for entry in fs::read_dir(dir).unwrap() {
            let path: PathBuf = entry.unwrap().path();
            if path.extension().unwrap().to_str() != Some("dat") {
                continue;
            }
            let stem = path.file_stem().unwrap().to_str().unwrap();
            if !stem.starts_with("chunk") {
                continue;
            }

            let s: Vec<&str> = stem.split("_").collect();
            let pos = Point3{x: s[1].parse::<u32>().unwrap(), y: s[2].parse::<u32>().unwrap(), z: s[3].parse::<u32>().unwrap()};

            let mut bytes = Vec::new();
            let mut file = fs::File::open(path).expect("Failed to open file");
            file.read_to_end(&mut bytes).expect("Failed to read file");
            let chunk = WorldChunk::from_bytes(bytes);

            println!("loaded {:?}", pos);
            self.chunks.insert(pos, chunk);
        }

        // Load metadata

    }

    pub fn gen_block(&mut self, block_wpos: &Point3<u32>) -> &WorldBlock {
        // Split world space to chunk and block space
        let ch_pos = block_wpos / chunk::SIZE as u32;
        let bl_pos = block_wpos % chunk::SIZE as u32;
        // Create chunk if does not exist
        if let None = self.chunks.get(&ch_pos) {
            self.chunks.insert(ch_pos.clone(), WorldChunk::new());
            println!("Alloc chunk [{}, {}, {}]", ch_pos.x, ch_pos.y, ch_pos.z);
        }
        // Generate block for chunk
        let chunk = self.chunks.get_mut(&ch_pos).unwrap();
        let block = chunk.get_block(&bl_pos);
        WorldGen::generate(&block_wpos, block);
        block
    }

    #[allow(unused)]
    pub fn get_block(&mut self, block_wpos: &Point3<u32>) -> Option<&WorldBlock> {
        // Split world space to chunk and block space
        let ch_pos = block_wpos / chunk::SIZE as u32;
        let bl_pos = block_wpos % chunk::SIZE as u32;
        // Return block if exists
        if let Some(chunk) = self.chunks.get_mut(&ch_pos) {
            return Some(chunk.get_block(&bl_pos));
        }
        None
    }
}