using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using Newtonsoft.Json.Linq;

// Displays the player's ships and lets them pick one.
public class PlayerShipSelector : MonoBehaviour {

    // Invoked when the player chooses a ship. name is the ship name, def is
    // the serialized AssembledShip.
    public delegate void OnShipSelected(string name, JObject def);

    // Prefab that handles the layout of the ship selector.
    // Must have a ShipSelector script.
    public GameObject selectorPrefab;
    // ScrollView containing the menu, to enable scrolling to show the selected
    // item.
    public ScrollRect scroller;
    public OnShipSelected callback;

    private int selectedIndex;
    private List<string> shipNames = new List<string>();
    private List<JObject> shipDefs = new List<JObject>();
    private List<ShipInfoBox> selectors = new List<ShipInfoBox>();
    private JObject playerShips;

	void Start () {
        selectedIndex = 0;
        playerShips = SaveData.Retrieve(SaveData.PlayerShipsKey);
        foreach (var def in playerShips) {
            shipNames.Add(def.Key);
            var shipData = def.Value.ToObject<JObject>();
            shipDefs.Add(shipData);
            var prefab = Instantiate(selectorPrefab);
            prefab.transform.SetParent(gameObject.transform, false);
            var selector = prefab.GetComponent<ShipInfoBox>();
            selectors.Add(selector);
            selector.ImportDef(def.Key, shipData);
        }
        InputDirector.PushListener(this, true);
    }

    public void OnDestroy() {
        InputDirector.PopListener(this);
    }

    void Update () {
        Debug.Log("Callback for " + gameObject.name + " is " + callback);
        if (InputDirector.GetButtonDown(this, "Select")) {
            if (callback == null) {
                throw new System.Exception("Must provide a callback to ShipSelector!");
            }
            callback(shipNames[selectedIndex], shipDefs[selectedIndex]);
            Destroy(gameObject);
        }
        var dy = InputDirector.GetButtonDown(this, "Menu Up") ? -1 : InputDirector.GetButtonDown(this, "Menu Down") ? 1 : 0;
        if (dy != 0) {
            selectedIndex = Op.Mod(selectedIndex + dy, selectors.Count);
            scroller.verticalNormalizedPosition = 1 - ((float)selectedIndex) / selectors.Count;
            for (int i = 0; i < selectors.Count; ++i) {
                var s = selectors[i];
                s.shipName.color = (i == selectedIndex) ? Color.cyan : Color.grey;
            }
        }
	}

    // Instantiate the dialog, and destroy it and invoke the provided callback
    // when a selection is made.
    public static void InstantiateWithCallback(GameObject prefab, Transform parent, OnShipSelected callback) {
        Debug.Log("Instantiator invoked with callback " + callback);
        var dialog = Instantiate(prefab);
        dialog.transform.SetParent(parent, false);
        Debug.Log("There are " + prefab.GetComponentsInChildren<PlayerShipSelector>().Length + " selectors");
        var selector = prefab.GetComponentInChildren<PlayerShipSelector>();
        Debug.Log("Found selector " + selector);
        selector.callback = (string name, JObject def) => {
            Destroy(prefab);
            callback(name, def);
        };
        Debug.Log("Set callback for " + selector.gameObject.name + " to " + selector.callback.ToString());
    }
}