/*
 * This file is part of Applied Energistics 2.
 * Copyright (c) 2013 - 2014, AlgorithmX2, All rights reserved.
 *
 * Applied Energistics 2 is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Applied Energistics 2 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Applied Energistics 2.  If not, see <http://www.gnu.org/licenses/lgpl>.
 */

package appeng.helpers;


import appeng.api.AEApi;
import appeng.api.networking.crafting.ICraftingPatternDetails;
import appeng.api.storage.channels.IItemStorageChannel;
import appeng.api.storage.data.IAEItemStack;
import appeng.container.ContainerNull;
import appeng.util.Platform;
import appeng.util.item.AEItemStack;
import net.minecraft.inventory.InventoryCrafting;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.item.crafting.CraftingManager;
import net.minecraft.item.crafting.IRecipe;
import net.minecraft.item.crafting.Ingredient;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.nbt.NBTTagList;
import net.minecraft.util.NonNullList;
import net.minecraft.world.World;
import net.minecraftforge.common.crafting.IShapedRecipe;

import java.util.*;

import static appeng.helpers.ItemStackHelper.stackFromNBT;


public class PatternHelper implements ICraftingPatternDetails, Comparable<PatternHelper> {

    public static final int CRAFTING_GRID_DIMENSION = 3;
    private static final int CRAFTING_INPUT_LIMIT = CRAFTING_GRID_DIMENSION * CRAFTING_GRID_DIMENSION;
    public static final int PROCESSING_INPUT_HEIGHT = 4;
    public static final int PROCESSING_INPUT_WIDTH = 4;
    public static final int PROCESSING_INPUT_LIMIT = PROCESSING_INPUT_HEIGHT * PROCESSING_INPUT_WIDTH;
    public static final int CRAFTING_OUTPUT_LIMIT = 1;
    public static final int PROCESSING_OUTPUT_LIMIT = 6;

    private final ItemStack patternItem;
    private final InventoryCrafting crafting;
    private final InventoryCrafting testFrame;
    private final ItemStack correctOutput;
    private final IRecipe standardRecipe;
    private final IAEItemStack[] condensedInputs;
    private final IAEItemStack[] condensedOutputs;
    private final IAEItemStack[] inputs;
    private final IAEItemStack[] outputs;
    private final Map<Integer, List<IAEItemStack>> substituteInputs;
    private final boolean isCrafting;
    private final boolean canSubstitute;
    private final Set<TestLookup> failCache = new HashSet<>();
    private final Set<TestLookup> passCache = new HashSet<>();
    private final IAEItemStack pattern;
    private int priority = 0;

    public PatternHelper(final ItemStack is, final World w) {
        final NBTTagCompound encodedValue = is.getTagCompound();

        if (encodedValue == null) {
            throw new IllegalArgumentException("No pattern here!");
        }

        final NBTTagList inTag = encodedValue.getTagList("in", 10);
        final NBTTagList outTag = encodedValue.getTagList("out", 10);
        this.isCrafting = encodedValue.getBoolean("crafting");

        crafting = new InventoryCrafting(new ContainerNull(), isCrafting ? 3 : 4, isCrafting ? 3 : 4);
        testFrame = new InventoryCrafting(new ContainerNull(), isCrafting ? 3 : 4, isCrafting ? 3 : 4);

        this.canSubstitute = this.isCrafting && encodedValue.getBoolean("substitute");
        this.patternItem = is;
        this.pattern = AEItemStack.fromItemStack(is);

        final List<IAEItemStack> in = new ArrayList<>();
        final List<IAEItemStack> out = new ArrayList<>();

        for (int x = 0; x < inTag.tagCount(); x++) {
            NBTTagCompound ingredient = inTag.getCompoundTagAt(x);
            final ItemStack gs = stackFromNBT(ingredient);

            if (!ingredient.hasNoTags() && gs.isEmpty()) {
                throw new IllegalArgumentException("No pattern here!");
            }

            this.crafting.setInventorySlotContents(x, gs);

            if (!gs.isEmpty() && (!this.isCrafting || !gs.hasTagCompound())) {
                this.markItemAs(x, gs, TestStatus.ACCEPT);
            }

            in.add(AEApi.instance().storage().getStorageChannel(IItemStorageChannel.class).createStack(gs));
            this.testFrame.setInventorySlotContents(x, gs);
        }

        if (this.isCrafting) {
            this.standardRecipe = CraftingManager.findMatchingRecipe(this.crafting, w);

            if (this.standardRecipe != null) {
                this.correctOutput = this.standardRecipe.getCraftingResult(this.crafting);
                out.add(AEApi.instance().storage().getStorageChannel(IItemStorageChannel.class).createStack(this.correctOutput));
            } else {
                throw new IllegalStateException("No pattern here!");
            }
        } else {
            this.standardRecipe = null;
            this.correctOutput = ItemStack.EMPTY;

            for (int x = 0; x < outTag.tagCount(); x++) {
                NBTTagCompound resultItemTag = outTag.getCompoundTagAt(x);
                final ItemStack gs = stackFromNBT(resultItemTag);

                if (!resultItemTag.hasNoTags() && gs.isEmpty()) {
                    throw new IllegalArgumentException("No pattern here!");
                }

                if (!gs.isEmpty()) {
                    out.add(AEApi.instance().storage().getStorageChannel(IItemStorageChannel.class).createStack(gs));
                }
            }
        }
        final int outputLength = out.size();

        this.inputs = in.toArray(new IAEItemStack[isCrafting ? CRAFTING_INPUT_LIMIT : PROCESSING_INPUT_LIMIT]);
        this.outputs = out.toArray(new IAEItemStack[outputLength]);
        this.substituteInputs = new HashMap<>(CRAFTING_INPUT_LIMIT);

        final Map<IAEItemStack, IAEItemStack> tmpOutputs = new HashMap<>();

        for (final IAEItemStack io : this.outputs) {
            if (io == null) {
                continue;
            }

            final IAEItemStack g = tmpOutputs.get(io);

            if (g == null) {
                tmpOutputs.put(io, io.copy());
            } else {
                g.add(io);
            }
        }

        final Map<IAEItemStack, IAEItemStack> tmpInputs = new HashMap<>();

        for (final IAEItemStack io : this.inputs) {
            if (io == null) {
                continue;
            }

            final IAEItemStack g = tmpInputs.get(io);

            if (g == null) {
                tmpInputs.put(io, io.copy());
            } else {
                g.add(io);
            }
        }

        if (tmpOutputs.isEmpty() || tmpInputs.isEmpty()) {
            throw new IllegalStateException("No pattern here!");
        }

        this.condensedInputs = new IAEItemStack[tmpInputs.size()];
        int offset = 0;

        for (final IAEItemStack io : tmpInputs.values()) {
            this.condensedInputs[offset] = io;
            offset++;
        }

        offset = 0;
        this.condensedOutputs = new IAEItemStack[tmpOutputs.size()];

        for (final IAEItemStack io : tmpOutputs.values()) {
            this.condensedOutputs[offset] = io;
            offset++;
        }
    }

    private void markItemAs(final int slotIndex, final ItemStack i, final TestStatus b) {
        if (b == TestStatus.TEST || i.hasTagCompound()) {
            return;
        }

        (b == TestStatus.ACCEPT ? this.passCache : this.failCache).add(new TestLookup(slotIndex, i));
    }

    @Override
    public ItemStack getPattern() {
        return this.patternItem;
    }

    @Override
    public synchronized boolean isValidItemForSlot(final int slotIndex, final ItemStack i, final World w) {
        if (!this.isCrafting) {
            throw new IllegalStateException("Only crafting recipes supported.");
        }

        final TestStatus result = this.getStatus(slotIndex, i);

        switch (result) {
            case ACCEPT:
                return true;
            case DECLINE:
                return false;
            case TEST:
            default:
                break;
        }

        for (int x = 0; x < this.crafting.getSizeInventory(); x++) {
            this.testFrame.setInventorySlotContents(x, this.crafting.getStackInSlot(x));
        }

        this.testFrame.setInventorySlotContents(slotIndex, i);

        // If we cannot substitute, the items must match exactly
        if ((!(i.getItem().isDamageable() || Platform.isGTDamageableItem(i.getItem())) && !canSubstitute) && slotIndex < inputs.length) {
            if (!inputs[slotIndex].isSameType(i)) {
                this.markItemAs(slotIndex, i, TestStatus.DECLINE);
                return false;
            }
        }

        if (this.standardRecipe.matches(this.testFrame, w)) {
            final ItemStack testOutput = this.standardRecipe.getCraftingResult(this.testFrame);

            if (Platform.itemComparisons().isSameItem(this.correctOutput, testOutput)) {
                this.testFrame.setInventorySlotContents(slotIndex, this.crafting.getStackInSlot(slotIndex));
                this.markItemAs(slotIndex, i, TestStatus.ACCEPT);
                return true;
            }
        }

        this.markItemAs(slotIndex, i, TestStatus.DECLINE);
        return false;
    }

    @Override
    public boolean isCraftable() {
        return this.isCrafting;
    }

    @Override
    public IAEItemStack[] getInputs() {
        return this.inputs;
    }

    @Override
    public IAEItemStack[] getCondensedInputs() {
        return this.condensedInputs;
    }

    @Override
    public IAEItemStack[] getCondensedOutputs() {
        return this.condensedOutputs;
    }

    @Override
    public IAEItemStack[] getOutputs() {
        return this.outputs;
    }

    @Override
    public boolean canSubstitute() {
        return this.canSubstitute;
    }

    @Override
    public List<IAEItemStack> getSubstituteInputs(int slot) {
        if (this.inputs[slot] == null) {
            return Collections.emptyList();
        }

        return this.substituteInputs.computeIfAbsent(slot, value -> {
            ItemStack[] matchingStacks = getRecipeIngredient(slot).getMatchingStacks();
            List<IAEItemStack> itemList = new ArrayList<>(matchingStacks.length + 1);
            for (ItemStack matchingStack : matchingStacks) {
                itemList.add(AEItemStack.fromItemStack(matchingStack));
            }

            // Ensure that the specific item put in by the user is at the beginning,
            // so that it takes precedence over substitutions
            itemList.add(0, this.inputs[slot]);
            return itemList;
        });
    }

    /**
     * Gets the {@link Ingredient} from the actual used recipe for a given slot-index into {@link #getInputs()}.
     * <p/>
     * Conversion is needed for two reasons: our sparse ingredients are always organized in a 3x3 grid, while Vanilla's
     * ingredient list will be condensed to the actual recipe's grid size. In addition, in our 3x3 grid, the user can
     * shift the actual recipe input to the right and down.
     */
    private Ingredient getRecipeIngredient(int slot) {

        if (standardRecipe instanceof IShapedRecipe) {
            IShapedRecipe shapedRecipe = (IShapedRecipe) standardRecipe;

            return getShapedRecipeIngredient(slot, shapedRecipe.getRecipeWidth());
        } else {
            return getShapelessRecipeIngredient(slot);
        }
    }

    private Ingredient getShapedRecipeIngredient(int slot, int recipeWidth) {
        // Compute the offset of the user's input vs. crafting grid origin
        // Which is >0 if they have empty rows above or to the left of their input
        int topOffset = 0;
        if (inputs[0] == null && inputs[1] == null && inputs[2] == null) {
            topOffset++; // First row is fully empty
            if (inputs[3] == null && inputs[4] == null && inputs[5] == null) {
                topOffset++; // Second row is fully empty
            }
        }
        int leftOffset = 0;
        if (inputs[0] == null && inputs[3] == null && inputs[6] == null) {
            leftOffset++; // First column is fully empty
            if (inputs[1] == null && inputs[4] == null && inputs[7] == null) {
                leftOffset++; // Second column is fully empty
            }
        }

        // Compute the x,y of the slot, as-if the recipe was anchored to 0,0
        int slotX = slot % CRAFTING_GRID_DIMENSION - leftOffset;
        int slotY = slot / CRAFTING_GRID_DIMENSION - topOffset;

        // Compute the index into the recipe's ingredient list now
        int ingredientIndex = slotY * recipeWidth + slotX;

        NonNullList<Ingredient> ingredients = standardRecipe.getIngredients();

        if (ingredientIndex < 0 || ingredientIndex > ingredients.size()) {
            return Ingredient.EMPTY;
        }

        return ingredients.get(ingredientIndex);
    }

    private Ingredient getShapelessRecipeIngredient(int slot) {
        // We map the list of *filled* sparse inputs to the shapeless (ergo unordered)
        // ingredients. While these do not actually correspond to each other,
        // since both lists have the same length, the mapping is at least stable.
        int ingredientIndex = 0;
        for (int i = 0; i < slot; i++) {
            if (inputs[i] != null) {
                ingredientIndex++;
            }
        }

        NonNullList<Ingredient> ingredients = standardRecipe.getIngredients();
        if (ingredientIndex < ingredients.size()) {
            return ingredients.get(ingredientIndex);
        }

        return Ingredient.EMPTY;
    }

    @Override
    public ItemStack getOutput(final InventoryCrafting craftingInv, final World w) {
        if (!this.isCrafting) {
            throw new IllegalStateException("Only crafting recipes supported.");
        }

        for (int x = 0; x < craftingInv.getSizeInventory(); x++) {
            if (!this.isValidItemForSlot(x, craftingInv.getStackInSlot(x), w)) {
                return ItemStack.EMPTY;
            }
        }

        if (this.outputs != null && this.outputs.length > 0) {
            return this.outputs[0].createItemStack();
        }

        return ItemStack.EMPTY;
    }

    private TestStatus getStatus(final int slotIndex, final ItemStack i) {
        if (this.crafting.getStackInSlot(slotIndex).isEmpty()) {
            return i.isEmpty() ? TestStatus.ACCEPT : TestStatus.DECLINE;
        }

        if (i.isEmpty()) {
            return TestStatus.DECLINE;
        }

        if (i.hasTagCompound()) {
            return TestStatus.TEST;
        }

        if (this.passCache.contains(new TestLookup(slotIndex, i))) {
            return TestStatus.ACCEPT;
        }

        if (this.failCache.contains(new TestLookup(slotIndex, i))) {
            return TestStatus.DECLINE;
        }

        return TestStatus.TEST;
    }

    @Override
    public int getPriority() {
        return this.priority;
    }

    @Override
    public void setPriority(final int priority) {
        this.priority = priority;
    }

    @Override
    public int compareTo(final PatternHelper o) {
        return Integer.compare(o.priority, this.priority);
    }

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

    @Override
    public boolean equals(final Object obj) {
        if (obj == null) {
            return false;
        }
        if (this.getClass() != obj.getClass()) {
            return false;
        }

        final PatternHelper other = (PatternHelper) obj;

        if (this.pattern != null && other.pattern != null) {
            return this.pattern.equals(other.pattern);
        }
        return false;
    }

    private enum TestStatus {
        ACCEPT,
        DECLINE,
        TEST
    }

    private static final class TestLookup {

        private final int slot;
        private final int ref;
        private final int hash;

        public TestLookup(final int slot, final ItemStack i) {
            this(slot, i.getItem(), i.getItemDamage());
        }

        public TestLookup(final int slot, final Item item, final int dmg) {
            this.slot = slot;
            this.ref = (dmg << Platform.DEF_OFFSET) | (Item.getIdFromItem(item) & 0xffff);
            final int offset = 3 * slot;
            this.hash = (this.ref << offset) | (this.ref >> (offset + 32));
        }

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

        @Override
        public boolean equals(final Object obj) {
            final boolean equality;

            if (obj instanceof TestLookup) {
                final TestLookup b = (TestLookup) obj;

                equality = b.slot == this.slot && b.ref == this.ref;
            } else {
                equality = false;
            }

            return equality;
        }
    }
}