using UnityEngine;
using UnityEngine.Assertions;
using System;
using System.Collections.Generic;

// ----------------------------------------------------------------

public class VapCsvReader
{
    /// <summary>
    /// Delimiter used for parsing CSV files.
    /// </summary>
    private const char CsvDelimiter = '\t';

    /// <summary>
    /// We ignore columns marked with this key. They are only there to improve editing experience & convenience.
    /// </summary>
    private const string PresentationKey = "-";

    /// <summary>
    /// We treat columns marked with this key as key-value pairs, parsing them as such. Used for ids.
    /// </summary>
    private const string CustomDataKey = "!";

    /// <summary>
    /// Delimiter for parsing cells that themselves contain key-value pairs.
    /// </summary>
    private const char CustomDataDelimiter = ':';

    private static bool verticalMode;

    // ----------------------------------------------------------------

    /// <summary>
    /// Reads a CSV file into a dictionary.
    /// </summary>
    /// <param name="resourcePath">Path to the CSV file.</param>
    /// <returns>A dictionary of strings and list of strings.</returns>
    public static Dictionary<string, List<string>> ReadCsv(string resourcePath)
    {
        // Get text asset.
        var text = Resources.Load(resourcePath) as TextAsset;
        Assert.IsNotNull(text, string.Format("{0} not found!", resourcePath));

        // Create dict.
        var dict = new Dictionary<string, List<string>>();

        // Get rows.
        var rows = text.text.Split(new[] { Environment.NewLine }, StringSplitOptions.None);

        // Iterate, skipping first 2 rows (1st = keys, 2nd = presentation only).
        for (var i = 2; i < rows.Length; i++)
        {
            // Get all cells of the row.
            var cells = rows[i].Split(CsvDelimiter);

            // First cell is an id.
            var id = cells[0];

            // Or it ain't. :) In that case, carry on.
            if (id == string.Empty)
                continue;

            // Create a list.
            var list = new List<string>();

            // Add it to the dict.
            dict.Add(id, list);

            // Go thru the cells, skipping the first.
            for (var n = 1; n < cells.Length; n++)
            {
                // Add a cell's content to the list.
                list.Add(cells[n]);
            }
        }

        return dict;
    }

    // ----------------------------------------------------------------

    /// <summary>
    /// Includes data loaded from a CSV file into the given Dictionary.
    /// </summary>
    /// <param name="resourcePath">Path to the CSV file.</param>
    /// <param name="dict">The Dictionary to include into.</param>
    public static void IncludeCsvIntoDict(string resourcePath, Dictionary<string, object> dict)
    {
        // Set default mode.
        verticalMode = false;

        // Get text asset.
        var text = Resources.Load(resourcePath) as TextAsset;

        // Get rows.
        var rows = text.text.Split(new[] { Environment.NewLine }, StringSplitOptions.None);

        // The very first row is reserved for keys, so read that.
        var keys = rows[0].Split(CsvDelimiter);

        // Find the key which we'll use as the base for inclusion.
        var baseKeyIndex = Array.IndexOf(keys, "!MainKey");

        if (baseKeyIndex == -1)
        {
            baseKeyIndex = Array.IndexOf(keys, "!MainKeyVert");

            Assert.IsTrue(baseKeyIndex != -1, string.Format("{0} is missing a !MainKey or !MainKeyVert entry!", resourcePath));

            verticalMode = true;
        }

        // Iterate, skipping first 2 rows (1st = keys, 2nd = presentation only).
        for (var i = 2; i < rows.Length; i++)
        {
            // Get a row.
            var r = rows[i];

            // Get all cells of the row.
            var cells = r.Split(CsvDelimiter);

            // Determine the base key.
            var baseKey = cells[baseKeyIndex];

            // If the cell with the base key index is empty, nothing to do here. Skip the row.
            if (baseKey == string.Empty)
                continue;

            // Go thru keys.
            for (var n = 0; n < keys.Length; n++)
            {
                // Get a key.
                var key = keys[n];

                // Skip presentational keys and the base key index. Got nuttin' to do with those.
                if (key == PresentationKey || n == baseKeyIndex)
                    continue;

                // Get the cell content with the key's index.
                var cell = cells[n];

                // Empty cells don't wanna be touched. Skip 'em.
                if (cell == string.Empty)
                    continue;

                // If the key tells us to parse the cell as a key-value pair...
                if (key == CustomDataKey)
                {
                    Assert.IsTrue(cell.Contains(CustomDataDelimiter.ToString()), string.Format("{0} error in file {1}: Custom data must have '{2}' as key-value delimiter at row {3}, column {4}", typeof(VapCsvReader), resourcePath, CustomDataDelimiter, i + 1, n + 1));

                    // Split the cell by the custom data delimiter.
                    var data = cell.Split(CustomDataDelimiter);

                    // Set the key to the left side.
                    key = data[0].Trim();

                    // Set the cell content to the right side.
                    cell = data[1].Trim();
                }

                // Construct our final full key, so longed for for countless ages across many continents.
                var fullKey = baseKey + "." + key;

                // These verticals gotta be special, hm?
                if (verticalMode)
                {
                    fullKey = key + "." + baseKey;
                }

                // Bitch the fuck out of it when trying to add keys that're already there!
                Assert.IsTrue(!dict.ContainsKey(fullKey), string.Format("What the hell is wrong witchu' son? Somebody already slapped key '{0}' onto the dictionary! So either you or them is pretty misled, dude.", fullKey));

                // Add the key.
                dict.Add(fullKey, cell);

                // Fix any missing keys in the dictionary along the path to the full key. This is for other classes to be able to ask whether some key even exists before doing more work.
                // IMPORTANT: Me loves 'while trues'!
                while (true)
                {
                    // Get the index of the dot.
                    var dotidx = fullKey.LastIndexOf('.');

                    // If there ain't any, get the horse outta here.
                    if (dotidx == -1)
                        break;

                    // Chop the full key up to the last dot (exclusive).
                    fullKey = fullKey.Substring(0, dotidx);

                    // Now add it to the dict if it ain't there already.
                    if (!dict.ContainsKey(fullKey))
                    {
                        dict.Add(fullKey, null);
                    }

                    // And now, the bracket slide...
                }
            }
        }
    }
}