package codechicken.nei;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;

import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTTagCompound;

import org.apache.commons.io.IOUtils;

import com.google.common.io.Files;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.JsonSyntaxException;

import codechicken.core.CommonUtils;
import codechicken.nei.api.API;
import codechicken.nei.recipe.GuiCraftingRecipe;
import codechicken.nei.recipe.GuiRecipeTab;
import codechicken.nei.recipe.ICraftingHandler;
import codechicken.nei.recipe.IRecipeHandler;
import codechicken.nei.recipe.Recipe.RecipeId;
import codechicken.nei.recipe.RecipeHandlerRef;
import codechicken.nei.recipe.StackInfo;
import codechicken.nei.util.FavoriteStorage;
import codechicken.nei.util.NBTJson;

public class FavoriteRecipes {

    protected static final class FastKey {

        public final ItemStack stack;
        private int hash;

        public FastKey(ItemStack stack) {
            this.stack = stack;

            this.hash = 31 + Item.getIdFromItem(stack.getItem());
            this.hash = 31 * this.hash + stack.getItemDamage();
        }

        @Override
        public int hashCode() {
            return this.hash;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;

            if (o instanceof FastKey k && this.stack.getItem() == k.stack.getItem()
                    && this.stack.getItemDamage() == k.stack.getItemDamage()) {
                return this.stack == k.stack || Objects.equals(this.stack.stackTagCompound, k.stack.stackTagCompound);
            }

            return false;
        }
    }

    private static final RestartableTask singleRecipeFavoritesTask = new RestartableTask(
            "Generate Single-Recipe Favorites") {

        @Override
        public void execute() {
            final List<ICraftingHandler> handlers = GuiCraftingRecipe.getCraftingHandlers("all");
            final Map<FastKey, RecipeHandlerRef> autogeneratedRecipes = new HashMap<>();
            final Set<FastKey> whitelistItems = new HashSet<>(ItemList.items.size());
            final FavoriteStorage storage = new FavoriteStorage();

            for (ItemStack stack : ItemList.items) {
                whitelistItems.add(new FastKey(stack));
            }

            if (interrupted()) return;

            for (ICraftingHandler handler : handlers) {
                if (!GuiRecipeTab.getHandlerInfo(handler).getShowFavoritesButton()) continue;

                for (int i = 0; i < handler.numRecipes(); i++) {
                    RecipeHandlerRef ref = null;

                    for (PositionedStack result : getOutputs(handler, i)) {
                        ItemStack stack = StackInfo.getItemStackWithMinimumDamage(result.items);
                        final FastKey key = new FastKey(stack);

                        if (!whitelistItems.contains(key)) continue;

                        if (autogeneratedRecipes.get(key) == null) {

                            if (ref == null) {
                                ref = RecipeHandlerRef.of(handler, i);
                            }

                            autogeneratedRecipes.put(key, ref);
                        } else {
                            autogeneratedRecipes.remove(key);
                            whitelistItems.remove(key);
                        }

                    }
                }
                if (interrupted()) return;
            }

            final Map<RecipeHandlerRef, RecipeId> recipesCache = new HashMap<>();

            for (Map.Entry<FastKey, RecipeHandlerRef> entry : autogeneratedRecipes.entrySet()) {
                final RecipeId recipeId = recipesCache
                        .computeIfAbsent(entry.getValue(), r -> RecipeId.of(r.handler, r.recipeIndex));
                storage.add(entry.getKey().stack, recipeId);
            }

            FavoriteRecipes.autoFavorites = storage;
            updateSubsetVisibility();
        }

        protected List<PositionedStack> getOutputs(IRecipeHandler handler, int recipeIndex) {
            final PositionedStack pStackResult = handler.getResultStack(recipeIndex);
            return pStackResult != null ? Collections.singletonList(pStackResult) : handler.getOtherStacks(recipeIndex);
        }

    };

    private static final FavoriteStorage manualFavorites = new FavoriteStorage();
    private static FavoriteStorage autoFavorites = new FavoriteStorage();
    private static File favoriteFile;
    private static int revision = 0;

    static {
        API.addSubset("Favorites.Manual", manualFavorites::contains);
        API.addSubset("Favorites.Generated", stack -> FavoriteRecipes.autoFavorites.contains(stack));
    }

    private FavoriteRecipes() {}

    public static void load() {
        String worldPath = "global";

        if (NEIClientConfig.getBooleanSetting("inventory.favorites.worldSpecific")) {
            worldPath = NEIClientConfig.getWorldPath();
        }

        final File dir = new File(CommonUtils.getMinecraftDir(), "saves/NEI/" + worldPath);

        if (!dir.exists()) {
            dir.mkdirs();
        }

        favoriteFile = new File(dir, "favorites.ini");

        if (!favoriteFile.exists()) {
            final File globalFavorites = new File(CommonUtils.getMinecraftDir(), "saves/NEI/global/favorites.ini");
            final File configFavorites = new File(NEIClientConfig.configDir, "favorites.ini");
            final File defaultFavorites = configFavorites.exists() ? configFavorites : globalFavorites;

            if (defaultFavorites.exists()) {
                try {
                    if (favoriteFile.createNewFile()) {
                        InputStream src = new FileInputStream(defaultFavorites);
                        OutputStream dst = new FileOutputStream(favoriteFile);

                        IOUtils.copy(src, dst);

                        src.close();
                        dst.close();
                    }
                } catch (IOException e) {}
            }
        }

        loadData();
    }

    private static void loadData() {

        if (favoriteFile == null || !favoriteFile.exists()) {
            return;
        }

        List<String> itemStrings;

        try (FileInputStream reader = new FileInputStream(favoriteFile)) {
            NEIClientConfig.logger.info("Loading favorites from file {}", favoriteFile);
            itemStrings = IOUtils.readLines(reader, StandardCharsets.UTF_8);
        } catch (IOException e) {
            NEIClientConfig.logger.error("Failed to load favorites from file {}", favoriteFile, e);
            return;
        }

        final JsonParser parser = new JsonParser();
        boolean hasErrors = false;

        manualFavorites.clear();

        for (String itemStr : itemStrings) {

            if (itemStr.isEmpty() || itemStr.startsWith("#")) {
                continue;
            }

            try {
                JsonObject jsonObject = parser.parse(itemStr).getAsJsonObject();

                if (jsonObject.get("item") != null && jsonObject.get("recipeId") != null) {
                    final NBTTagCompound itemStackNBT = (NBTTagCompound) NBTJson.toNbt(jsonObject.get("item"));
                    final RecipeId recipeId = RecipeId.of(jsonObject.getAsJsonObject("recipeId"));
                    final ItemStack stack = StackInfo.loadFromNBT(itemStackNBT);

                    if (recipeId == null || stack == null) {
                        continue;
                    }

                    if (RecipeHandlerRef.of(recipeId) != null) {
                        manualFavorites.add(stack, recipeId);
                    } else {
                        hasErrors = true;
                    }

                }

            } catch (Exception e) {
                NEIClientConfig.logger.error("Failed to load favorite from json string: {}", itemStr);
                hasErrors = true;
            }

        }

        if (hasErrors) {

            try {
                Files.copy(
                        favoriteFile,
                        new File(favoriteFile.getAbsolutePath() + ".backup-" + System.currentTimeMillis()));
                NEIClientConfig.logger.info("Backed up invalid favorite file to {}", favoriteFile);
            } catch (IOException e) {
                NEIClientConfig.logger.error("Failed to backup invalid favorite file to {}", favoriteFile, e);
            }

            save();
        }

        loadAutoGeneratedRecipes();
    }

    public static RecipeId getManualFavorite(ItemStack stack) {
        if (NEIClientConfig.favoritesEnabled() && stack != null) {
            return manualFavorites.getRecipeId(stack);
        }
        return null;
    }

    public static ItemStack getManualFavorite(RecipeId recipeId) {
        if (NEIClientConfig.favoritesEnabled() && recipeId != null) {
            return manualFavorites.getItemStack(recipeId);
        }
        return null;
    }

    public static RecipeId getFavorite(ItemStack stack) {

        if (NEIClientConfig.favoritesEnabled() && stack != null) {
            final RecipeId recipeId = manualFavorites.getRecipeId(stack);
            return recipeId != null ? recipeId : autoFavorites.getRecipeId(stack);
        }

        return null;
    }

    public static ItemStack getFavorite(RecipeId recipeId) {

        if (NEIClientConfig.favoritesEnabled() && recipeId != null) {
            final ItemStack stack = manualFavorites.getItemStack(recipeId);
            return stack != null ? stack : autoFavorites.getItemStack(recipeId);
        }

        return null;
    }

    public static int size() {
        return manualFavorites.size() + autoFavorites.size();
    }

    public static void reload() {
        save();
        load();
    }

    public static boolean containsManual(ItemStack stack) {
        return getManualFavorite(stack) != null;
    }

    public static boolean contains(ItemStack stack) {
        return getFavorite(stack) != null;
    }

    public static void setFavorite(ItemStack stack, RecipeId recipeId) {
        if (stack == null) return;

        manualFavorites.removeItemStack(stack);

        if (recipeId != null) {
            manualFavorites.removeRecipeId(recipeId);
            manualFavorites.add(stack, recipeId);
        }

        updateSubsetVisibility();
    }

    public static void loadAutoGeneratedRecipes() {
        if (ItemList.loadFinished
                && NEIClientConfig.getBooleanSetting("inventory.favorites.generateSingleRecipeFavorites")) {
            singleRecipeFavoritesTask.restart();
        } else {
            singleRecipeFavoritesTask.stop();
            autoFavorites.clear();

            updateSubsetVisibility();
        }
    }

    protected static void updateSubsetVisibility() {
        SubsetWidget.updateHiddenItems();
        FavoriteRecipes.revision++;
    }

    public static int getRevision() {
        return revision;
    }

    public static void save() {

        if (favoriteFile == null) {
            return;
        }

        final List<String> strings = new ArrayList<>();

        for (Map.Entry<NBTTagCompound, RecipeId> entry : manualFavorites.getAllFavorites()) {

            try {
                final JsonObject line = new JsonObject();

                line.add("item", NBTJson.toJsonObject(entry.getKey()));
                line.add("recipeId", entry.getValue().toJsonObject());

                strings.add(NBTJson.toJson(line));
            } catch (JsonSyntaxException e) {
                NEIClientConfig.logger.error("Failed to stringify favorites ItemStack to json string");
            }

        }

        try (FileOutputStream output = new FileOutputStream(favoriteFile)) {
            IOUtils.writeLines(strings, "\n", output, StandardCharsets.UTF_8);
        } catch (IOException e) {
            NEIClientConfig.logger.error("Failed to save favorites list to file {}", favoriteFile, e);
        }
    }

}