package net.knarcraft.blacksmith.trait;

import net.citizensnpcs.api.npc.NPC;
import net.citizensnpcs.api.trait.Trait;
import net.knarcraft.blacksmith.BlacksmithPlugin;
import net.knarcraft.blacksmith.config.Setting;
import net.knarcraft.blacksmith.config.Settings;
import net.knarcraft.blacksmith.config.TraitSettings;
import net.knarcraft.blacksmith.formatting.TimeFormatter;
import net.knarcraft.blacksmith.manager.EconomyManager;
import net.knarcraft.knarlib.formatting.StringFormatter;
import org.bukkit.entity.Entity;
import org.bukkit.entity.LivingEntity;
import org.bukkit.entity.Player;
import org.bukkit.inventory.EntityEquipment;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.PlayerInventory;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.Calendar;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

import static net.knarcraft.blacksmith.formatting.BlacksmithStringFormatter.sendNPCMessage;

/**
 * A custom trait that utilizes sessions
 */
public abstract class CustomTrait<K extends Setting> extends Trait {

    protected Session session;
    protected TraitSettings<K> config;
    protected final Map<UUID, Calendar> coolDowns = new HashMap<>();
    protected long currentSessionStartTime = System.currentTimeMillis();

    /**
     * Instantiates a new custom trait
     *
     * @param name <p>The name of the new trait</p>
     */
    protected CustomTrait(String name) {
        super(name);
    }

    /**
     * Sets the trait settings object containing this trait's configuration
     *
     * @param config <p>The trait settings to use</p>
     */
    protected void setTraitSettings(TraitSettings<K> config) {
        this.config = config;
    }

    /**
     * Gets the settings used by this trait
     *
     * @return <p>The settings used by this trait</p>
     */
    public @Nullable Settings<K> getTraitSettings() {
        return this.config;
    }

    /**
     * Starts a new session, and prepares to repair the player's item
     *
     * @param player <p>The player to start the session for</p>
     */
    public abstract void startSession(@NotNull Player player);

    /**
     * Tries to continue the session for the given player
     *
     * @param player <p>The player to continue the session for</p>
     */
    public void continueSession(@NotNull Player player) {
        //Another player is using the blacksmith
        if (session.isNotInSession(player)) {
            sendNPCMessage(this.npc, player, config.getBusyWithPlayerMessage());
            return;
        }

        //The blacksmith is already reforging for the player
        if (session.isRunning()) {
            int timeRemaining = (int) ((session.getFinishTime() - System.currentTimeMillis()) / 1000);
            boolean showExactTime = showExactTime();
            sendNPCMessage(this.npc, player, StringFormatter.replacePlaceholder(config.getBusyWorkingMessage(),
                    "{time}", TimeFormatter.formatTime(showExactTime, timeRemaining)));
            return;
        }
        if (session.isSessionInvalid()) {
            //Quit if the player cannot afford, or has changed their item
            session = null;
        } else {
            //Start reforging for the player
            startMainAction(npc, player);
        }
    }

    /**
     * Gets whether this blacksmith is already in a reforging session
     *
     * @return <p>Whether already in a salvage session</p>
     */
    public boolean hasSession() {
        return this.session != null;
    }

    /**
     * Adds a cool-down for the given player's next blacksmith reforge
     *
     * @param playerUUID <p>The ID of the player to add the cool-down for</p>
     * @param waitUntil  <p>The time when the player can interact again</p>
     */
    public void addCoolDown(@NotNull UUID playerUUID, @NotNull Calendar waitUntil) {
        coolDowns.put(playerUUID, waitUntil);
    }

    /**
     * Unsets the session of this scrapper, making it ready for another round
     */
    public void unsetSession() {
        this.session = null;
    }

    /**
     * Performs necessary work before the session is started or continued
     *
     * @param player <p>The player to prepare the session for</p>
     * @return <p>True if preparations were successful. False if a session shouldn't be started</p>
     */
    public boolean prepareForSession(@NotNull Player player) {
        UUID playerId = player.getUniqueId();
        //If cool-down has been disabled after it was set for this player, remove the cool-down
        if (config.getDisableCoolDown() && coolDowns.get(playerId) != null) {
            coolDowns.remove(playerId);
        }
        //Deny if permission is missing
        if (!player.hasPermission("blacksmith.use")) {
            return false;
        }

        //Deny if on cool-down, or remove cool-down if expired
        if (coolDowns.get(playerId) != null) {
            Calendar calendar = Calendar.getInstance();
            if (!calendar.after(coolDowns.get(playerId))) {
                int secondDifference = (int) (coolDowns.get(playerId).getTimeInMillis() - calendar.getTimeInMillis()) / 1000;
                boolean exactTime = showExactTime();
                sendNPCMessage(this.npc, player, StringFormatter.replacePlaceholder(config.getCoolDownUnexpiredMessage(),
                        "{time}", TimeFormatter.formatTime(exactTime, secondDifference)));
                return false;
            }
            coolDowns.remove(playerId);
        }

        //If already in a session, but the player has failed to interact, and left the blacksmith, allow a new session
        Entity entity = npc.getEntity();
        if (entity == null) {
            BlacksmithPlugin.error("NPC session could not be started, as the NPC does not have a valid entity");
            return false;
        }
        if (session != null && !session.isRunning() && (System.currentTimeMillis() > currentSessionStartTime + 10 * 1000 ||
                entity.getLocation().distance(session.getPlayer().getLocation()) > 20)) {
            session = null;
        }
        return true;
    }

    /**
     * Gets whether to show exact time when displaying the remaining time left
     *
     * @return <p>Whether to show exact time, or vague words</p>
     */
    protected abstract boolean showExactTime();

    /**
     * Starts reforging the player's item
     *
     * @param npc    <p>The NPC performing the reforge</p>
     * @param player <p>The player that initiated the reforge</p>
     */
    private void startMainAction(@NotNull NPC npc, @NotNull Player player) {
        sendNPCMessage(this.npc, player, config.getStartWorkingMessage());

        boolean isBlacksmith = this instanceof BlacksmithTrait;

        if (isBlacksmith) {
            EconomyManager.withdrawBlacksmith(player);
        } else if (this.session instanceof SalvageSession salvageSession) {
            EconomyManager.withdrawScrapper(player, salvageSession.salvageMethod);
        }
        PlayerInventory playerInventory = player.getInventory();
        ItemStack heldItem = player.getInventory().getItemInMainHand();
        session.scheduleAction();

        //Display the item in the NPC's hand
        Entity entity = npc.getEntity();
        if (entity instanceof Player playerNPC) {
            playerNPC.getInventory().setItemInMainHand(heldItem);
        } else if (entity instanceof LivingEntity) {
            EntityEquipment equipment = ((LivingEntity) entity).getEquipment();
            if (equipment != null) {
                ((LivingEntity) entity).getEquipment().setItemInMainHand(heldItem);
            } else {
                BlacksmithPlugin.warn("Failed to update NPC item, as its equipment was irretrievable.");
            }
        }
        //Remove the item from the player's inventory
        if (this.session instanceof SalvageSession salvageSession) {
            // For scrappers, just reduce the amounts of items, unless the remaining stack is salvaged
            int amount = salvageSession.getItemsConsumed();
            if (amount != heldItem.getAmount()) {
                heldItem.setAmount(heldItem.getAmount() - amount);
                playerInventory.setItemInMainHand(heldItem);
                return;
            }
        }
        playerInventory.setItemInMainHand(null);
    }

}