#nullable enable
using System;
using System.Buffers;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text.RegularExpressions;

// ReSharper disable MemberCanBePrivate.Global

namespace T3.Core.Utils;

[SuppressMessage("ReSharper", "MemberCanBeInternal")]
public static class StringUtils
{
    public static unsafe bool Equals(ReadOnlySpan<char> a, ReadOnlySpan<char> b, bool ignoreCase)
    {
        var aLength = a.Length;
        if (aLength != b.Length)
            return false;

        // this is made unsafe to avoid the overhead of the span bounds check - it's safe because we checked the length already
        if (ignoreCase)
        {
            fixed (char* aPtr = a)
            fixed (char* bPtr = b)
            {
                for (var i = 0; i < aLength; i++)
                {
                    if (char.ToLowerInvariant(aPtr[i]) != char.ToLowerInvariant(bPtr[i]))
                        return false;
                }
            }
        }
        else
        {
            fixed (char* aPtr = a)
            fixed (char* bPtr = b)
            {
                for (var i = 0; i < aLength; i++)
                {
                    if (aPtr[i] != bPtr[i])
                        return false;
                }
            }
        }

        return true;
    }

    /// <summary>
    /// Splits the provided path by the directory separator character.
    /// Warning: not for use with windows-style absolute paths (e.g. C:\foo\bar or C:/foo/bar),
    /// though unix-style absolute paths will work (e.g. /foo/bar)
    /// </summary>
    /// <param name="path">The path to split</param>
    /// <param name="ranges">Ranges that can be used to create spans or substrings from the original path</param>
    /// <returns></returns>
    public static int SplitByDirectory(ReadOnlySpan<char> path, Span<Range> ranges)
    {
        int count = 0;
        int start = 0;
        for (int i = 0; i < path.Length; i++)
        {
            if (path[i] == '\\' || path[i] == '/')
            {
                if (i > start)
                {
                    ranges[count++] = new Range(start, i);
                }

                start = i + 1;
            }
        }

        if (path.Length > start)
        {
            ranges[count++] = new Range(start, path.Length);
        }

        return count;
    }

    public enum SearchResultIndex
    {
        BeforeTerm,
        AfterTerm,
        FirstIndex,
        LastIndex
    }

    public static bool TryFindIgnoringAllWhitespace(string text, string searchTerm, SearchResultIndex searchResultIndex, out int indexFollowingSearchTerm,
                                                    int startIndex = 0)
    {
        // search the given string for the search term, ignoring all whitespace in both strings. " \ta b" == "ab"
        var searchTextLength = text.Length;

        // remove all whitespace from searchTerm
        searchTerm = RemoveWhitespaceFrom(searchTerm);

        var searchTermLength = searchTerm.Length;

        int currentSearchIndex = 0;
        char currentSearchChar = searchTerm[currentSearchIndex];
        int firstIndex = -1;

        for (int j = startIndex; j < searchTextLength; j++)
        {
            var textChar = text[j];

            if (char.IsWhiteSpace(textChar))
                continue;

            if (text[j] != currentSearchChar)
            {
                currentSearchIndex = 0;
                currentSearchChar = searchTerm[0];
                firstIndex = -1;
                continue;
            }

            if (firstIndex == -1)
                firstIndex = j;

            ++currentSearchIndex;
            if (currentSearchIndex == searchTermLength)
            {
                indexFollowingSearchTerm = searchResultIndex switch
                                               {
                                                   SearchResultIndex.BeforeTerm => firstIndex - 1,
                                                   SearchResultIndex.AfterTerm  => j + 1,
                                                   SearchResultIndex.FirstIndex => firstIndex,
                                                   SearchResultIndex.LastIndex  => j,
                                                   _                            => throw new ArgumentOutOfRangeException(nameof(searchResultIndex))
                                               };
                indexFollowingSearchTerm = j + 1;
                return true;
            }

            currentSearchChar = searchTerm[currentSearchIndex];
        }

        indexFollowingSearchTerm = -1;
        return false;
    }

    public static string RemoveWhitespaceFrom(string str)
    {
        var strLength = str.Length;
        for (var i = 0; i < strLength; i++)
        {
            var c = str[i];
            if (char.IsWhiteSpace(c))
            {
                str = str.Remove(c);
                strLength = str.Length;
                i = 0;
            }
        }

        return str;
    }

    public static ReadOnlySpan<char> TrimStringToLineCount(ReadOnlySpan<char> message, int maxLines)
    {
        var messageLength = message.Length;

        if (messageLength == 0)
            return message;

        int lineCount = 0;
        int length = 0;
        int nextStartIndex = 0;

        while (lineCount < maxLines)
        {
            lineCount++;

            var newlineIndex = message[nextStartIndex..].IndexOf('\n');
            nextStartIndex += newlineIndex + 1;

            if (newlineIndex == -1 || nextStartIndex == messageLength)
            {
                length = messageLength;
                break;
            }

            length = nextStartIndex;
        }

        return message[..length];
    }

    /// <summary>
    /// Returns a list of keys to retrieve Vector components from a dictionary.
    ///
    /// This can ne useful to extract the x,y,z components from OSC addresses with successive names like "Position.X", "Position.Y", ""Position.Z".
    /// Giving the key "Position.X" it will return all three keys. This also works for "Position1Key", "Position2Key",... 
    /// The keys are ordered before search.
    /// If the keys differ in more than one character it will return false.
    /// </summary>
    public static bool TryUpdateVectorKeysRelatedToX(Dictionary<string,float>? dict, string? xKey, ref List<string> vectorKeys, int count)
    {
        if (dict == null || dict.Count < count || string.IsNullOrEmpty(xKey))
            return false;

        vectorKeys.Clear();

        var justFoundX = false;
        var keyCount = dict.Count;
        var pool = ArrayPool<string>.Shared;
        var keys = pool.Rent(keyCount);

        int i = 0;
        foreach (var key in dict.Keys)
            keys[i++] = key;

        Array.Sort(keys, 0, keyCount, StringComparer.Ordinal);

        for (i = 0; i < keyCount; i++)
        {
            var key = keys[i];

            if (key == xKey)
                justFoundX = true;

            if (!justFoundX)
                continue;

            if (--count >= 0 && CountDifferentChars(key, xKey) <= 1)
            {
                vectorKeys.Add(key);
            }
            else
            {
                break;
            }
        }

        pool.Return(keys, clearArray: false);
        return count < 0;

        static int CountDifferentChars(string a, string b)
        {
            if (a.Length != b.Length)
                return int.MaxValue;

            int diffCount = 0;
            for (int i = 0; i < a.Length; i++)
                if (a[i] != b[i])
                    diffCount++;

            return diffCount;
        }
    }
    
    public static int IndexOfNot(this ReadOnlySpan<char> span, char c, bool ignoreCase, out char nextChar)
    {
        if (ignoreCase)
        {
            c = char.ToLowerInvariant(c);
            for (var i = 0; i < span.Length; i++)
            {
                nextChar = span[i];
                if (char.ToLowerInvariant(nextChar) != c)
                {
                    return i;
                }
            }

            nextChar = default;
            return -1;
        }

        for (var i = 0; i < span.Length; i++)
        {
            nextChar = span[i];
            if (nextChar != c)
                return i;
        }

        nextChar = default;
        return -1;
    }

    public static int LineCount(this string input)
    {
        if (string.IsNullOrEmpty(input))
            return 0;

        int count = 1; // At least one line if the string is not empty
        for (int i = 0; i < input.Length; i++)
        {
            if (input[i] == '\n')
                count++;
        }

        return count;
    }

    public static int IndexOf(this ReadOnlySpan<char> span, char c, bool ignoreCase)
    {
        if (ignoreCase)
        {
            c = char.ToLowerInvariant(c);
            for (var i = 0; i < span.Length; i++)
            {
                if (char.ToLowerInvariant(span[i]) == c)
                    return i;
            }

            return -1;
        }

        for (var i = 0; i < span.Length; i++)
        {
            if (span[i] == c)
                return i;
        }

        return -1;
    }

    public static int LastIndexOf(this ReadOnlySpan<char> span, char c, bool ignoreCase)
    {
        if (ignoreCase)
        {
            c = char.ToLowerInvariant(c);
            for (var i = span.Length - 1; i >= 0; i--)
            {
                if (char.ToLowerInvariant(span[i]) == c)
                    return i;
            }

            return -1;
        }

        for (var i = span.Length - 1; i >= 0; i--)
        {
            if (span[i] == c)
                return i;
        }

        return -1;
    }

    public static int LastIndexOfNot(this ReadOnlySpan<char> span, char c, bool ignoreCase, out char precedingChar)
    {
        if (ignoreCase)
        {
            c = char.ToLowerInvariant(c);
            for (var i = span.Length - 1; i >= 0; i--)
            {
                precedingChar = span[i];
                ;
                if (char.ToLowerInvariant(precedingChar) != c)
                    return i;
            }

            precedingChar = default;
            return -1;
        }

        for (var i = span.Length - 1; i >= 0; i--)
        {
            precedingChar = span[i];
            if (precedingChar != c)
                return i;
        }

        precedingChar = default;
        return -1;
    }
    
    
    

    /// <summary>
    /// A naive implementation of a filtering algorithm that supports wildcards ('*').
    /// 
    /// It is designed to be highly optimized, but it may not behave how you expect.
    /// This will accept an infinite amount of wildcards and treat them all the same -
    /// so "a*b**c" will match "a/b/anything/c" (expected) and "a/anything/b/c" (possibly unexpected) -
    /// there is no special directory treatment as is standard in most file search implementations.
    /// 
    /// Technically, the search begins from the end of the filter and the end of the possible match, and works backwards.
    /// 
    /// This is mostly intended for use in file path searches, where the end of the path is the most likely to be the most specific,
    /// and the end of the search term is most likely to change with consecutive calls.
    /// </summary>
    /// <param name="possibleMatch">string you want to check for a match</param>
    /// <param name="filter">The filter to match against</param>
    /// <param name="ignoreCase"></param>
    /// <returns>True if the provided string matches the provided filter</returns>
    public static bool MatchesSearchFilter(ReadOnlySpan<char> possibleMatch, ReadOnlySpan<char> filter, bool ignoreCase)
    {
        while (filter.Length > 0)
        {
            // the possible match has been exhausted but the filter has not
            if (possibleMatch.Length == 0)
                return false;

            var nextFilterChar = filter[^1];

            if (nextFilterChar == '*')
            {
                var nextNonWildcardIndex = filter.LastIndexOfNot('*', ignoreCase, out nextFilterChar);
                if (nextNonWildcardIndex == -1)
                    return true;

                var matchIndex = possibleMatch.LastIndexOf(nextFilterChar, ignoreCase);
                if (matchIndex == -1)
                    return false;

                // remove the last character from both strings to continue the search
                filter = filter[..nextNonWildcardIndex];
                possibleMatch = possibleMatch[..matchIndex];
            }
            else if (possibleMatch[^1] == nextFilterChar)
            {
                // remove the last character from both strings to continue the search
                possibleMatch = possibleMatch[..^1];
                filter = filter[..^1];
            }
            else
            {
                // no match /:
                return false;
            }
        }

        // we finished the filter - it's a match!
        return true;
    }

    public static unsafe void ReplaceCharUnsafe(this string str, char toReplace, char replacement)
    {
        fixed (char* strPtr = str)
        {
            for (int i = 0; i < str.Length; i++)
            {
                if (strPtr[i] == toReplace)
                    strPtr[i] = replacement;
            }
        }
    }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static void ToForwardSlashesUnsafe(this string str)
    {
        str.ReplaceCharUnsafe('\\', '/');
    }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static string ToForwardSlashes(this string str) => str.Replace('\\', '/');

    public static string Truncate(this string? input, int maxLength = 10)
    {
        if (input == null)
            return "null";

        if (input.Length < maxLength)
        {
            return input;
        }

        return input[..Math.Min(input.Length, maxLength)] + "...";
    }

    public static string HumanReadableDurationFromSeconds(double seconds)
    {
        return $"{(int)(seconds / 60 / 60):00}:{(seconds / 60) % 60:00}:{seconds % 60:00}";
    }

    public static string GetReadableRelativeTime(this DateTime? time)
    {
        if (time == null)
            return "Unknown time";

        var timeSpan = DateTime.Now - time;
        return GetReadableRelativeTime(timeSpan);
    }

    public static string GetReadableRelativeTime(double time)
    {
        return GetReadableRelativeTime(TimeSpan.FromSeconds(time));
    }

    public static string GetReadableFileSize(long size)
    {
        var gb = 1024 * 1024 * 1024;
        var mb = 1024 * 1024;
        
        if (size > gb)
        {
            // ReSharper disable once PossibleLossOfFraction
            return $"{size * 100 / gb * 0.01f:0.00} Gb";
        }

        if (size > mb)
        {
            // ReSharper disable once PossibleLossOfFraction
            return $"{size * 100 / mb * 0.01f:0.00} Mb";
        }

        return $"{size} bytes";
    }

    private static string GetReadableRelativeTime([DisallowNull] TimeSpan? timeSpan)
    {
        var seconds = timeSpan.Value.TotalSeconds;
        if (seconds < 60)
        {
            return "seconds ago";
        }

        var minutes = timeSpan.Value.TotalMinutes;
        if (minutes < 120)
        {
            return $"{minutes:0} min ago";
        }

        var hours = timeSpan.Value.TotalHours;
        if (hours < 30)
        {
            return $"{hours:0.0} h ago";
        }

        var days = timeSpan.Value.TotalDays;
        return $"{days:0.0} days ago";
    }

    private static readonly Regex _matchFileVersionPattern = new(@"\b(\d{1,4})\b");
    
    public static string AppendOrIncrementVersionNumber(this string original)
    {
        if (string.IsNullOrEmpty(original))
            return original;
        
        var result = _matchFileVersionPattern.Match(original);
        if (result.Success)
        {
            var versionString = result.Groups[1].Value;
            if (!int.TryParse(versionString, out var versionNumber)) 
                return original;

            var newVersionString = (versionNumber + 1).ToString();
            return original.Replace(versionString, newVersionString);            
        }

        return original + " 2";
    }

    /// <summary>
    /// Parse a string like...
    ///
    /// Failed to update shader "PixelShader_PixelShaderFromSource (5e6d5cb9-df8f-494d-b50e-31499b257f34)" in package "Types":
    /// Failed to compile shader 'PixelShader_PixelShaderFromSource (5e6d5cb9-df8f-494d-b50e-31499b257f34)'.
    /// Line 37,31:  error X3000: unrecognized identifier 'x'
    /// </summary>
    public static List<string> ParseShaderCompilationError(string log)
    {
        List<string> results = new();
        ReadOnlySpan<char> logSpan = log;

        ReadOnlySpan<char> separator = ": ";

        while (!logSpan.IsEmpty)
        {
            var newlineIndex = logSpan.IndexOf('\n');
            var line = newlineIndex >= 0 ? logSpan[..newlineIndex] : logSpan;

            line = line.TrimStart();

            if (line.StartsWith("Line "))
            {
                var commaIndex = line.IndexOf(',');
                if (commaIndex > 5 && int.TryParse(line.Slice(5, commaIndex - 5), out var lineNumber))
                {
                    // Find the error message after ": "
                    var firstColonIndex = line.IndexOf(": ");
                    if (firstColonIndex >= 0)
                    {
                        var t = firstColonIndex + separator.Length;
                        var secondColonIndex = line[t..].IndexOf(separator) + t;
                        if (secondColonIndex >= 0 && secondColonIndex + 2 < line.Length)
                        {
                            var errorMessage = line.Slice(secondColonIndex + 2);

                            // Skip the error code (first word)
                            var spaceIndex = errorMessage.IndexOf(' ');
                            if (spaceIndex >= 0 && spaceIndex + 1 < errorMessage.Length)
                            {
                                var errorString = new string(errorMessage.Slice(spaceIndex + 1)); // Minimal allocation
                                results.Add($"Line {lineNumber}: {errorString}");
                            }
                        }
                    }
                }
            }

            if (newlineIndex < 0) break;
            logSpan = logSpan[(newlineIndex + 1)..]; // Move to next line
        }

        return results;
    }

    public static int LevenshteinDistance(ReadOnlySpan<char> s, ReadOnlySpan<char> t)
    {
        if (s.Length == 0) return t.Length;
        if (t.Length == 0) return s.Length;

        // Use two rows to save memory
        var v0 = new int[t.Length + 1];
        var v1 = new int[t.Length + 1];

        for (var i = 0; i <= t.Length; i++)
            v0[i] = i;

        for (var i = 0; i < s.Length; i++)
        {
            v1[0] = i + 1;

            for (var j = 0; j < t.Length; j++)
            {
                var cost = (s[i] == t[j]) ? 0 : 1;
                v1[j + 1] = Math.Min(v1[j] + 1, Math.Min(v0[j + 1] + 1, v0[j] + cost));
            }

            Array.Copy(v1, v0, v0.Length);
        }

        return v0[t.Length];
    }
    
    
    public static string ShortenGuid(this Guid guid, int length = 7)
    {
        if (length < 1 || length > 22)
            throw new ArgumentOutOfRangeException(nameof(length), "Length must be between 1 and 22.");

        var guidBytes = guid.ToByteArray();
        var base64 = Convert.ToBase64String(guidBytes);
        var alphanumeric = base64.Replace("+", "").Replace("/", "").Replace("=", "");
        return alphanumeric[..length];
    }
    
    
    public static string ToValidClassName(this string input, string fallback = "ClassName")
    {
        if (string.IsNullOrWhiteSpace(input))
            return fallback;
        
        var cleaned = Regex.Replace(input, @"[^a-zA-Z0-9_]", "");
        
        if (char.IsDigit(cleaned, 0))
            cleaned = "_" + cleaned;
        
        return string.IsNullOrEmpty(cleaned) ? "ClassName" : cleaned;
    }
    
    public static ReadOnlySpan<char> SliceToProgress(string text, float progress)
    {
        if (string.IsNullOrEmpty(text))
            return ReadOnlySpan<char>.Empty;

        progress = Math.Clamp(progress, 0f, 1f);

        // floor is usually what you want for a typewriter reveal
        var len = (int)(text.Length * progress);

        if ((uint)len > (uint)text.Length)
            len = text.Length;

        return text.AsSpan(0, len);
    }

    /// <summary>
    
    /// </summary>
    public static Guid GenerateGuidFromString(this string name)
    {
        if (string.IsNullOrEmpty(name))
            return Guid.Empty;

        // Use MD5 to create a deterministic 16-byte hash from the name
        using var md5 = System.Security.Cryptography.MD5.Create();
        byte[] hash = md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(name));
        return new Guid(hash);
    }
}