#include "Binder.hpp"

BoundScriptStatement *Binder::Bind(Script* script, ParsedScriptStatement *s, BoundScope* scriptScope) {
    auto binder = Binder();
    binder._scriptData = script;

    binder._scope = scriptScope;
    auto statements = s->GetStatements();
    vector<BoundStatement*> boundStatements (statements.size());
    for (int i = 0; i < statements.size(); i++){
        boundStatements[i] = binder.BindStatement(statements[i]);
    }
    return new BoundScriptStatement(boundStatements, scriptScope->GetDeepestScope());
}

Binder::~Binder() {
    delete _scope;
}

BoundStatement* Binder::BindStatement(ParsedStatement* statement){
    switch (statement -> GetKind()) {
        case ParsedStatementKind ::Script: throw; // This shouldn't happen.
        case ParsedStatementKind ::Block: return this -> BindBlockStatement(statement);
        case ParsedStatementKind ::Expression: return this -> BindExpressionStatement(statement);
        case ParsedStatementKind::Assignment: return this -> BindAssignmentStatement(statement);
        case ParsedStatementKind ::FunctionDeclaration: return this->BindFunctionDeclarationStatement(statement);

        case ParsedStatementKind::Bad: return new BoundBadStatement();
    }
}

BoundStatement *Binder::BindBlockStatement(ParsedStatement *statement) {
    auto statements = ((ParsedBlockStatement*)statement)->GetStatements();
    vector<BoundStatement*> boundStatements (statements.size());
    this->_scope->GoInnerScope();
    for (int i = 0; i < statements.size(); i++){
        boundStatements[i] = this -> BindStatement(statements[i]);
    }
    this->_scope->GoOuterScope();
    return new BoundBlockStatement(boundStatements);
}

BoundStatement *Binder::BindExpressionStatement(ParsedStatement *statement) {
    auto exp = ((ParsedExpressionStatement*)statement)->GetExpression();
    return new BoundExpressionStatement(this -> BindExpression(exp));
}

BoundStatement* Binder::BindAssignmentStatement(ParsedStatement *statement){
    auto s = (ParsedAssignmentStatement*) statement;
    auto boundExpression = this->BindExpression(s->GetExpression());
    VariableAssignment assignment =
            s->IsLocal() ?
                this->_scope->CreateExplicitLocal(s->GetIdentifier().GetHash(), *boundExpression->GetType())
                : this->_scope->AssignVariable(s->GetIdentifier().GetHash(), *boundExpression->GetType());
    if (assignment.GetResult() == VariableAssignmentResult::Ok){
        auto key = assignment.GetKey();
        return new BoundAssignmentStatement(key, boundExpression);
    }
    else{
        this -> _scriptData -> Diagnostics -> LogError(DiagnosticCode::CantAssignVariable, statement->GetStartPosition(), statement->GetLength());
        return new BoundBadStatement();
    }
}

ScriptType* ParseTypeIdentifier(HashedString s){
    switch (s.GetHash()){
        case HashedString::ConstHash("number"): return new NumericScriptType(false, false);
        case HashedString::ConstHash("bool"): return new ScriptType(TypeClass::Bool);
        case HashedString::ConstHash("string"): return new ScriptType(TypeClass::String);
        default: return new ScriptType(TypeClass::Error); // todo: change to userdata
    }
}

BoundStatement *Binder::BindFunctionDeclarationStatement(ParsedStatement *statement) {
    auto functionStatement = (ParsedFunctionDeclarationStatement*) statement;
    auto parameters = functionStatement->GetParameters();
    vector<ScriptType*> parameterTypes = vector<ScriptType*>(parameters.size());
    vector<int> parameterKeys = vector<int>(parameters.size());
    this->_scope->GoInnerScope();
    auto scopeId = this->_scope->GetCurrentScope();
    for (int i = 0; i < parameters.size(); i++){
        auto var = parameters[i];
        auto parsedType = ParseTypeIdentifier(var->GetType());
        parameterTypes[i] = parsedType;
        parameterKeys[i] = var->GetIdentifier().GetHash();
        this->_scope->CreateExplicitLocal(var->GetIdentifier().GetHash(), *parsedType);
    }
    auto boundBlock = this -> BindBlockStatement(functionStatement->GetBlock());
    this->_scope->GoOuterScope();
    auto identifier = functionStatement->GetIdentifier();
    auto returnType = new ScriptType(TypeClass::Nil);
    auto type = new FunctionScriptType(returnType, parameterTypes, parameterKeys, scopeId);
    auto assignment = this->_scope->AssignVariable(identifier.GetHash(), *type);
    if (assignment.GetResult() == VariableAssignmentResult::Ok){
        return new BoundFunctionDeclarationStatement(type, assignment.GetKey(), (BoundBlockStatement*)boundBlock);
    }
    return new BoundBadStatement();
}

BoundExpression* Binder::BindExpression(ParsedExpression* expression){
    switch (expression -> GetKind()){
        case ParsedExpressionKind ::LiteralInteger:
            return new BoundLiteralIntegerExpression(((LiteralIntegerExpression*)expression)->GetValue(), expression->GetStartPosition(), expression->GetLength());
        case ParsedExpressionKind ::LiteralFloat:
            return new BoundLiteralFloatExpression(((LiteralFloatExpression*)expression)->GetValue(), expression->GetStartPosition(), expression->GetLength());
        case ParsedExpressionKind ::LiteralString:
            return new BoundLiteralStringExpression(((LiteralStringExpression*)expression)->GetValue(), expression->GetStartPosition(), expression->GetLength());
        case ParsedExpressionKind ::LiteralBool:
            return new BoundLiteralBoolExpression(((LiteralBoolExpression*)expression)->GetValue(), expression->GetStartPosition(), expression->GetLength());
        case ParsedExpressionKind ::Variable:
            return this -> BindVariableExpression((VariableExpression*)expression);

        case ParsedExpressionKind ::Binary:
            return this -> BindBinaryOperator((BinaryExpression*)expression);
        case ParsedExpressionKind ::Unary:
            return this -> BindUnaryOperator((UnaryExpression*)expression);

        case ParsedExpressionKind ::Parenthesized:
            return BindExpression(((ParenthesizedExpression*)expression)->GetInnerExpression());

        case ParsedExpressionKind ::Bad:
            return new BoundBadExpression(expression->GetStartPosition(), expression-> GetLength());
    }
}

BoundExpression* Binder::BindVariableExpression(VariableExpression* expression){
    auto key = expression->GetValue();
    auto scope = this->_scope->Exists(key.GetHash());
    if (scope == -1){
        this -> _scriptData -> Diagnostics->LogError(DiagnosticCode::VariableNotFound, expression->GetStartPosition(), expression->GetLength());
        return new BoundBadExpression(expression->GetStartPosition(), expression->GetLength());
    }
    auto var = this->_scope->GetVariable(scope, key.GetHash());
    auto type = var->GetType();
    return new BoundVariableExpression(scope, key.GetHash(), type, expression->GetStartPosition(), expression->GetLength());
}

BoundExpression* Binder::BindBinaryOperator(BinaryExpression* expression){
    auto boundLeft = this -> BindExpression(expression->GetLeft());
    auto boundRight = this -> BindExpression(expression->GetRight());

    auto boundLeftType = boundLeft->GetType();
    auto boundRightType = boundRight->GetType();

    switch (expression->GetOperatorKind()){
        case BinaryOperatorKind ::Addition:
            if (boundLeftType->GetClass() == TypeClass::Number && boundRightType->GetClass() == TypeClass::Number){
                auto leftNumeric = (NumericScriptType*)boundLeftType;
                auto rightNumeric = (NumericScriptType*)boundRightType;
                if (leftNumeric->IsAwareOfFloat() && rightNumeric->IsAwareOfFloat()){
                    return new BoundBinaryExpression(boundLeft, boundRight,
                            BoundBinaryOperation::Addition, new NumericScriptType(true, leftNumeric->IsFloat() || rightNumeric->IsFloat()),
                            expression->GetStartPosition(), expression->GetLength());
                }
                else{
                    return new BoundBinaryExpression(boundLeft, boundRight, BoundBinaryOperation::Addition, new NumericScriptType(false, false),
                                                     expression->GetStartPosition(), expression->GetLength());
                }
            } else if (boundLeftType->GetClass() == TypeClass::String){
                return new BoundBinaryExpression(boundLeft, boundRight, BoundBinaryOperation::Concatenation, new ScriptType(TypeClass::String),
                                                 expression->GetStartPosition(), expression->GetLength());
            }
            break;
        case BinaryOperatorKind ::Subtraction:
            if (boundLeftType->GetClass() == TypeClass::Number && boundRightType->GetClass() == TypeClass::Number){
                auto leftNumeric = (NumericScriptType*)boundLeftType;
                auto rightNumeric = (NumericScriptType*)boundRightType;
                if (leftNumeric->IsAwareOfFloat() && rightNumeric->IsAwareOfFloat()){
                    return new BoundBinaryExpression(boundLeft, boundRight,
                                                     BoundBinaryOperation::Subtraction,
                                                     new NumericScriptType(true, leftNumeric->IsFloat() || rightNumeric->IsFloat()),
                                                     expression->GetStartPosition(), expression->GetLength());
                }
                else{
                    return new BoundBinaryExpression(boundLeft, boundRight, BoundBinaryOperation::Subtraction, new NumericScriptType(false, false),
                                                     expression->GetStartPosition(), expression->GetLength());
                }
            }
            break;
        case BinaryOperatorKind ::Multiplication:
            if (boundLeftType->GetClass() == TypeClass::Number && boundRightType->GetClass() == TypeClass::Number){
                auto leftNumeric = (NumericScriptType*)boundLeftType;
                auto rightNumeric = (NumericScriptType*)boundRightType;
                if (leftNumeric->IsAwareOfFloat() && rightNumeric->IsAwareOfFloat()){
                    return new BoundBinaryExpression(boundLeft, boundRight,
                                                     BoundBinaryOperation::Multiplication,
                                                     new NumericScriptType(true, leftNumeric->IsFloat() || rightNumeric->IsFloat()),
                                                     expression->GetStartPosition(), expression->GetLength());
                }
                else{
                    return new BoundBinaryExpression(boundLeft, boundRight, BoundBinaryOperation::Multiplication, new NumericScriptType(false, false),
                                                     expression->GetStartPosition(), expression->GetLength());
                }
            }
            break;
        case BinaryOperatorKind ::Division:
            if (boundLeftType->GetClass() == TypeClass::Number && boundRightType->GetClass() == TypeClass::Number){
                auto leftNumeric = (NumericScriptType*)boundLeftType;
                auto rightNumeric = (NumericScriptType*)boundRightType;
                if (leftNumeric->IsAwareOfFloat() && rightNumeric->IsAwareOfFloat()){
                    return new BoundBinaryExpression(boundLeft, boundRight,
                                                     BoundBinaryOperation::Division,
                                                     new NumericScriptType(true, leftNumeric->IsFloat() || rightNumeric->IsFloat()),
                                                     expression->GetStartPosition(), expression->GetLength());
                }
                else{
                    return new BoundBinaryExpression(boundLeft, boundRight, BoundBinaryOperation::Division, new NumericScriptType(false, false),
                                                     expression->GetStartPosition(), expression->GetLength());
                }
            }
            break;
        case BinaryOperatorKind ::Equality:
            return new BoundBinaryExpression(boundLeft, boundRight, BoundBinaryOperation::Equality, new ScriptType(TypeClass::Bool),
                                             expression->GetStartPosition(), expression->GetLength());
        case BinaryOperatorKind ::Inequality:
            return new BoundBinaryExpression(boundLeft, boundRight, BoundBinaryOperation::Inequality, new ScriptType(TypeClass::Bool),
                                             expression->GetStartPosition(), expression->GetLength());
        case BinaryOperatorKind ::LogicalAnd:
            if (boundLeftType->GetClass() == TypeClass::Bool && boundRightType->GetClass() == TypeClass::Bool)
                return new BoundBinaryExpression(boundLeft, boundRight, BoundBinaryOperation::LogicalAnd, new ScriptType(TypeClass::Bool),
                                                 expression->GetStartPosition(), expression->GetLength());
            break;
        case BinaryOperatorKind ::LogicalOr:
            if (boundLeftType->GetClass() == TypeClass::Bool && boundRightType->GetClass() == TypeClass::Bool)
                return new BoundBinaryExpression(boundLeft, boundRight, BoundBinaryOperation::LogicalOr, new ScriptType(TypeClass::Bool),
                                                 expression->GetStartPosition(), expression->GetLength());
            break;
    }
    this -> _scriptData -> Diagnostics->LogError(DiagnosticCode::NoBinaryOperationFound, expression->GetStartPosition(), expression->GetLength());
    return new BoundBadExpression(expression->GetStartPosition(), expression->GetLength());
}

BoundExpression* Binder::BindUnaryOperator(UnaryExpression* expression){
    auto operand = this -> BindExpression(expression->GetOperand());
    auto operandType = operand -> GetType();
    switch (expression->GetOperatorKind()){
        case UnaryOperatorKind ::Identity:
            if (operandType->GetClass() == TypeClass::Number){
                // Identity won't change anything during evaluation, so just return the inner operand.
                return operand;
            }
            break;
        case UnaryOperatorKind ::Negation:
            if (operandType->GetClass() == TypeClass::Number){
                auto innerType = (NumericScriptType*)operandType;
                return new BoundUnaryExpression(operand, BoundUnaryOperation::Negation, new NumericScriptType(innerType->IsAwareOfFloat(),
                        innerType->IsFloat()), expression->GetStartPosition(), expression->GetLength());
            }
            break;
        case UnaryOperatorKind ::LogicalNegation:
            if (operandType->GetClass() == TypeClass::Bool){
                return new BoundUnaryExpression(operand, BoundUnaryOperation::LogicalNegation, new ScriptType(TypeClass::Bool),
                        expression->GetStartPosition(), expression->GetLength());
            }
            break;
        default:
            break;
    }
    this -> _scriptData -> Diagnostics->LogError(DiagnosticCode::NoUnaryOperationFound, expression->GetStartPosition(), expression->GetLength());
    return new BoundBadExpression(expression->GetStartPosition(), expression->GetLength());

}