using EC.Helper.RabbitFunc.Compiler;
using EC.Helper.RabbitFunc.Expressions;

namespace EC.Helper.RabbitFunc;

public class RabbitDomain
{
    private readonly Dictionary<string, LambdaExpression> lambdas = new Dictionary<string, LambdaExpression>();

    public void Register(LambdaExpression lambda)
    {
        if (lambda == null)
            throw new ArgumentNullException(nameof(lambda));

        lambdas[lambda.Name] = lambda;
    }

    public bool TryGetLambda(string name, out LambdaExpression? lambda)
    {
        if (lambdas.TryGetValue(name, out lambda))
        {
            return true;
        }
        if (Rabbit.TryGetSystemLambda(name, out var systemLambda))
        {
            lambda = systemLambda;
            return true;
        }

        return false;
    }

    public LambdaExpression? GetLambda(string name)
    {
        TryGetLambda(name, out LambdaExpression? lambda);
        return lambda;
    }

    public LambdaExpression CompileFromSource(string source)
    {
        if (source == null)
            throw new ArgumentNullException(nameof(source));

        LambdaExpression? lambda = null;
        using var reader = new StringReader(source);
        var tokenizer = new Tokenizer(reader);
        var parser = new Parser(tokenizer);
        while (!tokenizer.EndOfStream)
        {
            var expression = parser.Parse();
            if (expression == null) break;

            expression.Domain = this;
            Register(expression);
            lambda = expression;
        }

        return lambda ?? throw new CompilerException(tokenizer.Position, "The formula was not found");
    }

    public LambdaExpression CompileFromFile(string path)
    {
        if (path == null)
            throw new ArgumentNullException(nameof(path));

        LambdaExpression? lambda = null;
        using var stream = new FileStream(path, FileMode.Open, FileAccess.Read);
        using var reader = new StreamReader(stream, System.Text.Encoding.UTF8);
        var tokenizer = new Tokenizer(reader);
        var parser = new Parser(tokenizer);
        while (!tokenizer.EndOfStream)
        {
            var expression = parser.Parse();
            if (expression == null) break;

            expression.Domain = this;
            Register(expression);
            lambda = expression;
        }

        return lambda ?? throw new CompilerException(tokenizer.Position, "The formula was not found");
    }
}