using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEngine;
using UnityEngine.Networking;
using UnityEngine.SceneManagement;
using UnityEngine.UI;
using exprivia;
using sam;

public class OrbitSelectSubsession : ProductSelectorSession
{
    Canvas canvas;

    public Text productNameText;
    public Text startTimeText;
    public Text endTimeText;

    public SatelliteDataTypeConfig cfg;
    DateTime startTime;
    DateTime endTime;
    string previousSceneName;

    public List<string> products = new List<string>();
    public List<(DateTime,DateTime)> productDates = new List<(DateTime, DateTime)>();
    public int selectedProductIndex = -1;

    bool flagInitialized = false;

    public override void Initialize(SatelliteDataTypeConfig _cfg, DateTime _startTime, DateTime _endTime, string psn)
    {
        flagInitialized = false;

        canvas = GetComponentInChildren<Canvas>();
        cfg = _cfg;
        startTime = _startTime;
        endTime = _endTime;
        previousSceneName = psn;

        StartCoroutine("FetchProductListCoroutine");
    }

    IEnumerator FetchProductListCoroutine()
    {
        products.Clear();
        productDates.Clear();

        startTimeText.text = startTime.ToString("MMMM dd yyyy, h:mm:ss tt");
        endTimeText.text = endTime.ToString("MMMM dd yyyy, h:mm:ss tt");

        int numDays =(int)((endTime - startTime).TotalDays + 1);

        for (int i = 0; i < numDays; i++)
        {
            DateTime d = startTime.AddDays(i);
            string daystring = d.ToString("yyyyMMdd");
            string url = cfg.url + "/Index/" + daystring + ".idx";

            UnityWebRequest webRequest = UnityWebRequestManager.GetUnityWebRequest(url);

            using (webRequest)
            {
                Debug.Log($"downloading idx file {url} ...");

                // Avoid reading product list from cache, as this could change on server. 
                // See EUAT-213
                webRequest.SetRequestHeader("Cache-Control", "max-age=0, no-cache, no-store");
                webRequest.SetRequestHeader("Pragma", "no-cache");

                // Request and wait for the desired resource.
                yield return webRequest.SendWebRequest();

                if (webRequest.result == UnityWebRequest.Result.ConnectionError || webRequest.result == UnityWebRequest.Result.ConnectionError)
                {
                    Debug.LogWarning("UnityWebRequest error: " + webRequest.error + " \"" + url + "\" ");
                    //onError(this);
                }
                else
                {
                    Debug.Log($"DownloadDataFile: downloaded file: {url}");

                    if (webRequest.downloadHandler.text[0] == '<')
                    {
                        Debug.LogWarning($"IdxFile {url} not found on server");
                    }
                    else
                    {
                        ProcessIdxFile(webRequest.downloadHandler.text);
                    }
                }
            }
        }

        if (products.Count == 0)
        {
            Debug.LogWarning("FetchProductListCoroutine: no products found");
            Sprite warningIcon = Resources.Load<Sprite>("Icons/Warning");
            PopUp.NewPopUp(canvas, warningIcon, "No products found in specified time interval", "Ok", (i) =>
            {
                Debug.Log($"FetchProductListCoroutine: Modal dialog closed with value {i}");
                if (!string.IsNullOrEmpty(previousSceneName))
                {
                    Debug.Log($"<color=white>SWITCHING BACK TO SCENE {previousSceneName}</color>");
                    exprivia.ui.Utils.LoadScene(previousSceneName);
                }
                else
                {
                    Debug.Log("<color=green>SHOULD GO BACK TO PREVIOUS SCENE</Color>");
                }
            });
            yield break;
        }

        selectedProductIndex = 0;

        BroadcastMessage("OnProductListUpdated", products, SendMessageOptions.DontRequireReceiver);
        flagInitialized = true;

        GameObject go = GetComponentInChildren<SpinnerController>()?.gameObject;
        if (go != null) Destroy(go);

        SelectProduct(0);

    }

    public void ProcessIdxFile(string text)
    {
        Debug.Log($"ProcessIdxFile called with text: \n{text}");

        using (var reader = new StringReader(text))
        {
            for (string line = reader.ReadLine(); line != null; line = reader.ReadLine())
            {
                // extract start and end time
                (DateTime start, DateTime end) dates = cfg.ExtractDatesFromFilename(line);

                if ((dates.end < startTime) || (dates.start > endTime))
                {
                    continue;
                }

                if (!products.Contains(line))
                {
                    products.Add(line);
                    productDates.Add(dates);
                }

            }
        }
    }

    public void SelectNextProduct()
    {
        if (flagInitialized)
            SelectProduct((selectedProductIndex + 1) % products.Count);
    }

    public void SelectPreviousProduct()
    {
        if (flagInitialized)
            SelectProduct((selectedProductIndex + products.Count - 1) % products.Count);
    }

    public void SelectProduct(int index)
    {
        selectedProductIndex = Mathf.Clamp(index, 0, products.Count-1);
        BroadcastMessage("OnOrbitSelected", (products[selectedProductIndex], productDates[selectedProductIndex]), SendMessageOptions.DontRequireReceiver);
    }

    public void OnOrbitSelected((string name, (DateTime start,DateTime end) dates) product)
    {
        productNameText.text = (cfg.productNameExtractionFunc != null) ?
            cfg.productNameExtractionFunc.ExtractProductName(product.name) : product.name;

        startTimeText.text = product.dates.start.ToString("MMMM dd yyyy, h:mm:ss tt");
        endTimeText.text = product.dates.end.ToString("MMMM dd yyyy, h:mm:ss tt");
    }

    public void VisualizeSelectedProduct()
    {
        // write to global dictionary:
        GlobalDictionary.SetValue("ProductName", products[selectedProductIndex]);
        GlobalDictionary.SetValue("SatelliteDataTypeConfig", cfg);
        GlobalDictionary.SetValue("DataVariableParentSceneName", SceneManager.GetActiveScene().name);

        string sceneName = cfg.dataVariableSceneName;

        Debug.Log($"<color=white>SWITCHING TO SCENE {sceneName}</color>");
        exprivia.ui.Utils.LoadScene(sceneName);
    }

    public void OnBackButtonPressed() {
        if (!string.IsNullOrEmpty(previousSceneName)) {
            Debug.Log($"<color=white>SWITCHING BACK TO SCENE {previousSceneName}</color>");
            exprivia.ui.Utils.LoadScene(previousSceneName);
        }
        else {
            Debug.Log("<color=green>SHOULD GO BACK TO PREVIOUS SCENE</Color>");
        }
    }
}