using System.Text.RegularExpressions;

ProcessDirectory(Directory.GetCurrentDirectory());

void ProcessDirectory(string baseDir) {
    foreach (var subDir in Directory.EnumerateFileSystemEntries(baseDir))
    {
        var fs = Path.Combine(baseDir, subDir);
        if (File.Exists(fs))
        {
            if (Path.GetFileName(fs) == "BUILD") FormatBuildFile(fs);
        } 
        else if (Directory.Exists(fs))
        {
            ProcessDirectory(fs);
        }
    }
}

void FormatBuildFile(string filename)
{
    var oldcontent = File.ReadAllText(filename);
    var newcontent = FormatFile(filename, oldcontent);

    if (oldcontent == newcontent) return;
    
    File.WriteAllText(filename, newcontent);
    Console.WriteLine("Auto-Formatted file :: " + filename);
}

string FormatFile(string filename, string content)
{
    var depsRex = new Regex(@"^\s*deps\s*=\s*\[(\s*\n)?(?<deps>[^\]\)]+?)[\s\r\n]*\]", RegexOptions.Multiline);    
    
    var matches = depsRex.Matches(content);

    foreach (Match m in matches)
    {
        var oldDeps = m.Groups["deps"].Value;
        if (string.IsNullOrWhiteSpace(oldDeps)) continue;
        
        var linenum = 1 + content[..m.Groups["deps"].Index].AsEnumerable().Count(p => p == '\n');
        
        var newDeps = FormatDeps(filename, linenum, oldDeps);

        if (oldDeps != newDeps) content = content.Replace(oldDeps, newDeps);
    }
    
    return content;
}

string FormatDeps(string filename, int linenum, string deps)
{
    var lines = deps.Split("\n");
    if (lines.Length == 0) return deps;

    var allindents = lines.Where(l => !string.IsNullOrWhiteSpace(l)).Select(l => l.Length - l.TrimStart().Length).Distinct().ToList();
    if (allindents.Count != 1)
    {
        throw new Exception($"Different deps-indents in file {filename}:{linenum} ( [ {string.Join(", ", allindents)} ] )");
    }

    var indent = new string(' ',  allindents[0]);

    var result = lines.
        Where(p => !string.IsNullOrWhiteSpace(p)).
        Select(p => GetDepGroup(filename, linenum, p)).
        GroupBy(p => p.group).
        OrderBy(p => p.Key).
        SelectMany(p => p.OrderBy(q => q.clean).Select(q => $"{indent}\"{q.clean}\",").Append("")).
        Aggregate((a, b) => a + "\n" + b);

    return result;
}

(int group, string sgroup, string clean, string raw) GetDepGroup(string filename, int linenum, string value)
{
    var v = value.Trim();

    var rowA = v.Length > 3 && v[0] == '"' && v[^2] == '"' && v[^1] == ',';
    var rowB = v.Length > 2 && v[0] == '"' && v[^1] == '"';
    
    if (!rowA && !rowB) throw new Exception($"Invalid Dependency in file {filename}:{linenum} => '{v}'");

    if (rowA)
    {
        v = v.Substring(1, v.Length - 3);
    } 
    else if (rowB)
    {
        v = v.Substring(1, v.Length - 2);
    }

    v = v.Trim();

    if (v.StartsWith(":")) return (100, "local", v, value);

    if (v.StartsWith("//common")) return (200, "common", v, value);
    if (v.StartsWith("//apcommon")) return (201, "common", v, value);

    if (v.StartsWith("//accessor")) return (220, "accessor", v, value);
    if (v.StartsWith("//models")) return (221, "models", v, value);
    if (v.StartsWith("//routing")) return (222, "routing", v, value);
    if (v.StartsWith("//service")) return (223, "service", v, value);
    if (v.StartsWith("//artifacts")) return (224, "artifacts", v, value);
    
    if (v.StartsWith("//services")) return (251, "services", v, value);
    if (v.StartsWith("//gateways")) return (252, "gateways", v, value);
    if (v.StartsWith("//jobs")) return (253, "jobs", v, value);

    if (v.StartsWith("//proto/common:")) return (401, "commonproto", v, value);
    if (v.StartsWith("//proto")) return (402, "proto", v, value);

    if (v.StartsWith("//library/go/private")) return (500, "privatelib", v, value);

    if (v.StartsWith("//library/go:")) return (501, "golib", v, value);

    if (v.StartsWith("//library/go/")) return (502, "sublib", v, value);

    throw new Exception($"unknown dep group in file {filename}:{linenum} => '{v}'");
}