using System.Reflection;
using NubLang.CLI;
using NubLang.Code;
using NubLang.Diagnostics;
using NubLang.Generation;
using NubLang.Generation.QBE;
using NubLang.Parsing;
using NubLang.Parsing.Syntax;
using NubLang.Tokenization;
using NubLang.TypeChecking;
using NubLang.TypeChecking.Node;

const string BIN_DIR = "bin";
const string INT_DIR = "bin-int";
var INT_BUILTIN_DIR = Path.Join(INT_DIR, "builtin");
var INT_OBJECT_DIR = Path.Join(INT_DIR, "obj");
var INT_DEBUG_DIR = Path.Join(INT_DIR, "debug");

if (Directory.Exists(INT_DIR))
{
    Directory.Delete(INT_DIR, true);
}

Directory.CreateDirectory(BIN_DIR);
Directory.CreateDirectory(INT_BUILTIN_DIR);
Directory.CreateDirectory(INT_OBJECT_DIR);
Directory.CreateDirectory(INT_DEBUG_DIR);

var options = new Options();

for (var i = 0; i < args.Length; i++)
{
    var arg = args[i];
    if (arg == "-r")
    {
        i++;
        if (i >= args.Length - 1)
        {
            Console.Error.WriteLine($"{arg} must be followed by a value");
            return 1;
        }

        options.CustomRuntime = args[i];
    }
    else if (arg == "-o")
    {
        i++;
        if (i >= args.Length - 1)
        {
            Console.Error.WriteLine($"{arg} must be followed by a value");
            return 1;
        }

        options.OutputPath = args[i];
    }
    else if (arg == "-c")
    {
        i++;
        options.Link = false;
    }
    else
    {
        options.Files.Add(new SourceFile(arg));
    }
}

var diagnostics = new List<Diagnostic>();
var syntaxTrees = new List<SyntaxTree>();

foreach (var file in options.Files)
{
    if (!File.Exists(file.Path))
    {
        Console.Error.WriteLine($"File '{file}' does not exist");
        return 1;
    }
}

foreach (var file in options.Files)
{
    var tokenizer = new Tokenizer(file);
    var tokens = tokenizer.Tokenize().ToList();
    diagnostics.AddRange(tokenizer.GetDiagnostics());

    var parser = new Parser();
    var syntaxTree = parser.Parse(tokens);

    diagnostics.AddRange(parser.GetDiagnostics());

    syntaxTrees.Add(syntaxTree);
}

var definitionTable = new DefinitionTable(syntaxTrees);

var typedSyntaxTrees = new List<TypedSyntaxTree>();

foreach (var syntaxTree in syntaxTrees)
{
    var typeChecker = new TypeChecker(syntaxTree, definitionTable);
    var typedSyntaxTree = typeChecker.Check();
    diagnostics.AddRange(typeChecker.GetDiagnostics());
    typedSyntaxTrees.Add(typedSyntaxTree);
}

foreach (var diagnostic in diagnostics)
{
    Console.Error.WriteLine(diagnostic.FormatANSI());
}

if (diagnostics.Any(diagnostic => diagnostic.Severity == DiagnosticSeverity.Error))
{
    return 1;
}

var typedDefinitionTable = new TypedDefinitionTable(typedSyntaxTrees);

var objectFiles = new List<string>();

for (var i = 0; i < typedSyntaxTrees.Count; i++)
{
    var syntaxTree = typedSyntaxTrees[i];
    var outFileName = Path.GetFileNameWithoutExtension(options.Files[i].Path);

    var generator = new QBEGenerator(syntaxTree, typedDefinitionTable);
    var ssa = generator.Emit();
    File.WriteAllText(Path.Join(INT_DEBUG_DIR, $"{outFileName}.ssa"), ssa);

    var asm = await QBE.Invoke(ssa);
    if (asm == null)
    {
        return 1;
    }

    File.WriteAllText(Path.Join(INT_DEBUG_DIR, $"{outFileName}.s"), asm);

    var fileName = Path.Join(INT_OBJECT_DIR, $"{outFileName}.o");
    var asmSuccess = await GCC.Assemble(asm, fileName);
    if (!asmSuccess)
    {
        return 1;
    }

    objectFiles.Add(fileName);
}

if (options.CustomRuntime == null)
{
    try
    {
        objectFiles.Add(await CreateBuiltinRuntime());
    }
    catch (RuntimeCreationException e)
    {
        Console.Error.WriteLine(e.Message);
        return 1;
    }
}
else
{
    if (!File.Exists(options.CustomRuntime))
    {
        Console.Error.WriteLine($"file '{options.CustomRuntime}' does not exist'");
        return 1;
    }

    objectFiles.Add(options.CustomRuntime);
}

if (options.Link)
{
    var outPath = options.OutputPath ?? Path.Join(BIN_DIR, "out");
    var linkResult = await GCC.Link(outPath, objectFiles);
    if (!linkResult)
    {
        return 1;
    }
}
else
{
    var outPath = options.OutputPath ?? Path.Join(BIN_DIR, "out.a");
    var archiveResult = await Archive.Invoke(outPath, objectFiles);
    if (!archiveResult)
    {
        return 1;
    }
}

return 0;

async Task<string> CreateBuiltinRuntime()
{
    const string RUNTIME_NAME = "libruntime_x64.a";

    var resources = Assembly.GetExecutingAssembly().GetManifestResourceNames();
    var runtime = resources.First(r => r.EndsWith(RUNTIME_NAME));

    await using var reader = Assembly.GetExecutingAssembly().GetManifestResourceStream(runtime);

    if (reader == null)
    {
        throw new RuntimeCreationException($"Cannot open stream to '{RUNTIME_NAME}'");
    }

    var runtimePath = Path.Combine(INT_BUILTIN_DIR, RUNTIME_NAME);
    await using var writer = new FileStream(runtimePath, FileMode.Create);

    reader.CopyTo(writer);

    return runtimePath;
}

namespace NubLang.CLI
{
    internal class RuntimeCreationException(string message) : Exception(message);
}