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

public class MultiDownloadSubsession : ProductSelectorSession
{
    enum ViewMode
    {
        Select,
        Orbits
    }

    [FormerlySerializedAs("camera")]public Transform cam;
    public Transform earth;
    public Canvas canvas;

    public Text viewModeButtonText;
    public Text latitudeText;
    public Text longitudeText;

    ViewMode viewMode = ViewMode.Select;

    Vector3 capCenter;
    float capRadius = 15.0f;

    public SatelliteDataTypeConfig cfg;
    public DateTime startTime;
    public DateTime endTime;

    string previousSceneName;

    List<string> products = new List<string>();
    public List<(DateTime, DateTime)> productDates = new List<(DateTime, DateTime)>();

    public override void Initialize(SatelliteDataTypeConfig _cfg, DateTime _startTime, DateTime _endTime, string prevSceneName)
    {
        cfg = _cfg;
        startTime = _startTime;
        endTime = _endTime;
        previousSceneName = prevSceneName;
        StartCoroutine("FetchProductListCoroutine");
    }


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

        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 index file 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.LogError("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.LogError("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;
        }

        Debug.Log($"<color=red>FetchProductListCoroutine: found {products.Count} products </color>");

        BroadcastMessage("OnProductListUpdated", products, SendMessageOptions.DontRequireReceiver);
        BroadcastMessage("OnCapRadiusChanged", capRadius, SendMessageOptions.DontRequireReceiver);
    }

    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);

                Debug.Log($"PRODUCT RANGE from: {dates.start} to {dates.end}");

                if ((dates.end < startTime) || (dates.start > endTime))
                {
                    Debug.Log($"discarding product");
                    continue;
                }

                if (!products.Contains(line))
                {
                    products.Add(line);
                    productDates.Add(dates);
                    Debug.Log($"ADDED PRODUCT {products.Count}");
                }

            }
        }
    }


    public void OnViewModeButtonClicked()
    {
        if (viewMode == ViewMode.Select)
        {
            viewMode = ViewMode.Orbits;
            viewModeButtonText.text = "Select";
            BroadcastMessage("OnEnterOrbitsMode", (capCenter, capRadius), SendMessageOptions.DontRequireReceiver);
        }
        else
        {
            viewMode = ViewMode.Select;
            viewModeButtonText.text = "Orbits";
            BroadcastMessage("OnEnterSelectMode", SendMessageOptions.DontRequireReceiver);
        }
    }

    public void OnScaleSliderAction(float val)
    {
        capRadius = val;
        BroadcastMessage("OnCapRadiusChanged", capRadius, SendMessageOptions.DontRequireReceiver);
    }

    public void OnBackButtonClicked()
    {
        if (!string.IsNullOrEmpty(previousSceneName))
        {
            Debug.Log($"<color=white>SWITCHING BACK TO SCENE {previousSceneName}</color>");
            exprivia.ui.Utils.LoadScene(previousSceneName);
        }
    }

    void Update()
    {
        float epsilon = 0.00001f;

        if (viewMode == ViewMode.Select)
        {
            Vector3 c = cam.position - earth.position;
            c.Normalize();

            if (Math.Abs((c - capCenter).sqrMagnitude) < epsilon)
                return;

            capCenter = c;

            //Debug.Log($"CameraPos: {camera.position} EarthPos: {earth.position}  Delta:{capCenter}");

            (float,float) p = XYZToLonLat(capCenter);
            latitudeText.text = "Latitude: " + sam.Utils.FormatLatitude(p.Item2);
            longitudeText.text = "Longitude: " + sam.Utils.FormatLongitude(p.Item1);

            BroadcastMessage("OnCapCenterChanged", capCenter, SendMessageOptions.DontRequireReceiver);


            //Vector3 reprojected = Utils.DegLonLatHgtToXYZ(new Vector3(p.Item1, p.Item2, 0.0f), true);
            //Debug.Log($"capCenter: {capCenter} LonLat: {p}  reprojected:{reprojected}");
        }
    }

    (float lon, float lat) XYZToLonLat(Vector3 xyz)
    {
        float lat = (float)Math.Asin(xyz.y) * Mathf.Rad2Deg;
        if ((lat == -90.0f) || (lat == 90.0f)) return (0.0f, lat);
        float lon = -1f * ((float)Math.Atan2(xyz.x, xyz.z) * Mathf.Rad2Deg - 90.0f);
        return (lon, lat);
    }

}