package ru.m.data;

import flash.net.SharedObject;
import haxe.DynamicAccess;
import haxe.io.Bytes;
import haxe.Serializer;
import haxe.Unserializer;
import hw.connect.PacketUtil;
import promhx.Promise;
import ru.m.data.IDataSource;

class Converter<D, S> {
    private var serializer:D -> S;
    private var desirealizer:S -> D;

    public function new(serializer:D -> S, desirealizer:S -> D) {
        this.serializer = serializer;
        this.desirealizer = desirealizer;
    }

    public inline function serialize(item:D):S {
        return serializer(item);
    }

    public inline function deserialize(data:S):D {
        return desirealizer(data);
    }
}

class DefaultConverter<D> extends Converter<D, String> {
    public function new () {
        super(
            item -> Serializer.run(item),
            data -> new Unserializer(data).unserialize()
        );
    }
}

class ProtoConverter<D:protohx.Message> extends Converter<D, String> {
    public function new(messageClass:Class<D>) {
        super(
            item -> PacketUtil.toBytes(item).toHex(),
            data -> PacketUtil.fromBytes(Bytes.ofHex(data), messageClass)
        );
    }
}

class EmptyConverter<T> extends Converter<T, T> {
    public function new() {
        super(item -> item, data -> data);
    }
}

class MetaBuilder<D> extends DefaultConverter<DataMeta> {
    private var builder:D -> DataMeta;

    public function new(builder:D -> DataMeta) {
        super();
        this.builder = builder;
    }

    public function build(item:D):DataMeta {
        return builder(item);
    }
}

typedef DataMeta = Filter;

typedef IdValue<I> = {id:I, meta:DataMeta};

class DataStorage<I, D> implements IDataManager<I, D> implements IDataIndex<I> {

    inline private static var DATA_KEY = "item";

    private var name:String;
    private var metaBuilder:MetaBuilder<D>;
    private var idConverter:Converter<I, String>;
    private var dataConverter:Converter<D, Dynamic>;
    private var indexData:SharedObject;

    public function new(
        name:String,
        metaBuilder:MetaBuilder<D>,
        idConverter:Converter<I, String> = null,
        dataConverter:Converter<D, Dynamic> = null
    ) {
        this.name = name;
        this.metaBuilder = metaBuilder;
        this.idConverter = idConverter != null ? idConverter : new DefaultConverter();
        this.dataConverter = dataConverter != null ? dataConverter : new DefaultConverter();
        this.indexData = SharedObject.getLocal('${name}/index');
    }

    private function serializeId(id:I):String {
        return idConverter.serialize(id);
    }

    private function desirealizeId(data:String):I {
        return idConverter.deserialize(data);
    }

    private function buildMeta(item:D):DataMeta {
        return metaBuilder.build(item);
    }

    private function checkFilter(filter:Null<Filter>, meta:DataMeta):Bool {
        if (filter != null) {
            for (k => v in filter) {
                if (meta.exists(k) && meta.get(k) != v) {
                    return false;
                }
            }
        }
        return true;
    }

    private function sort(order:Order, values:Array<IdValue<I>>):Void {
        if (order != null) {
            values.sort((a:IdValue<I>, b:IdValue<I>) -> {
                for (item in order) {
                    var av = a.meta.get(item.key);
                    var bv = b.meta.get(item.key);
                    if (av > bv) {
                        return item.reverse ? - 1 : 1;
                    } else if (av < bv) {
                        return item.reverse ? 1 : -1;
                    }
                }
                return 0;
            });
        }
    }

    private function serialize(item:D):Dynamic {
        return dataConverter.serialize(item);
    }

    private function unserialize(data:Dynamic):D {
        return dataConverter.deserialize(data);
    }

    public function getIndexPage(page:Page):Promise<DataPage<I>> {
        var data:DynamicAccess<String> = indexData.data;
        var values:Array<IdValue<I>> = [];
        for (k => v in data) {
            var meta = metaBuilder.deserialize(v);
            if (checkFilter(page.filter, meta)) {
                values.push({id: desirealizeId(k), meta: meta});
            }
        }
        sort(page.order, values);
        var result:Array<I> = values.slice(page.index * page.count, page.index * page.count + page.count).map(value -> value.id);
        return Promise.promise({
            page: page,
            total: values.length,
            data: result,
        });
    }

    public function getPage(page:Page):Promise<DataPage<D>> {
        return getIndexPage(page).pipe((indexPage:DataPage<I>) -> {
            return Promise.whenAll([for (id in indexPage.data) get(id)]).then((data:Array<D>) -> {
                return {
                    page: indexPage.page,
                    total: indexPage.total,
                    data: data,
                }
            });
        });
    }

    public function get(id:I):Promise<D> {
        var stringId = serializeId(id);
        var itemData = SharedObject.getLocal('${name}/${stringId}');
        var result:D = null;
        if (Reflect.hasField(itemData.data, DATA_KEY)) {
            result = unserialize(Reflect.field(itemData.data, DATA_KEY));
        }
        return Promise.promise(result);
    }

    public function save(item:D):Promise<D> {
        var meta = metaBuilder.build(item);
        var stringId = meta.get("id");
        var itemData = SharedObject.getLocal('${name}/${stringId}');
        itemData.setProperty(DATA_KEY, serialize(item));
        itemData.flush();
        indexData.setProperty(stringId, metaBuilder.serialize(meta));
        indexData.flush();
        return Promise.promise(item);
    }

    public function delete(id:I):Promise<Bool> {
        var stringId = serializeId(id);
        var itemData = SharedObject.getLocal('${name}/${stringId}');
        itemData.clear();
        var data:DynamicAccess<String> = indexData.data;
        data.remove(stringId);
        indexData.flush();
        return Promise.promise(true);
    }
}