using System;
using UnityEngine;

[RequireComponent(typeof(ResourceSource))]
public class ResourceGenerator : MonoBehaviour
{
    public int Interval;

    public int Power = 0;

    private ResourceSource source;
    private long lastTime;

    [ContextMenu("Clear Last Generation Time")]
    public void ResetTime()
    {
        source = GetComponent<ResourceSource>();

        PlayerPrefs.DeleteKey(GetLastTimePrefName());
        PlayerPrefs.Save();
    }

    private void Start()
    {
        source = GetComponent<ResourceSource>();

        // PlayerPrefs.DeleteKey(GetLastTimePrefName());
        // PlayerPrefs.Save();

        lastTime = long.Parse(
            PlayerPrefs.GetString(GetLastTimePrefName(), GetCurrentTime().ToString())
        );

        GenerateToNow(false);
    }

    private long GetCurrentTime()
    {
        return DateTime.UtcNow.Ticks / TimeSpan.TicksPerMillisecond;
    }

    private string GetPrefName(string suffix)
    {
        return $"ResourceGenerator_{source.Resource.Name}_{suffix}";
    }

    private string GetLastTimePrefName()
    {
        return GetPrefName("LastTime");
    }

    private void Update()
    {
        GenerateToNow(true);

        PlayerPrefs.SetString(GetLastTimePrefName(), lastTime.ToString());
    }

    private void GenerateToNow(bool online)
    {
        var now = GetCurrentTime();
        GenerateToTime(now);
    }

    private void GenerateToTime(long time)
    {
        if (Interval == 0)
            return;

        var delta = time - lastTime;

        if (delta > 1e8)
        {
            Debug.Log($"Too much time has passed: {time - lastTime}");
            lastTime = time;
            return;
        }

        // Debug.Log($"{time} - {lastTime} = {delta} since last generation");

        long times = delta / Interval;
        if (times > 0)
        {
            Generate((int)times);
            lastTime += times * Interval;
        }
    }

    private void Generate(int times)
    {
        // Debug.Log($"+{Power}x{times} {source.Resource.Name}");
        ResourceStorage.Instance.AddResource(source.Resource, Power * times);
    }

    public float Progress
    {
        get
        {
            if (Interval == 0)
                return 0;

            var delta = GetCurrentTime() - lastTime;
            return Math.Clamp(delta * 1.0f / Interval, 0, 1);
        }
    }
}