/**************************************************************************/
/*  aethex_parser.cpp                                                     */
/**************************************************************************/
/*                         This file is part of:                          */
/*                          AETHEX ENGINE                                 */
/*                     https://aethex.foundation                          */
/**************************************************************************/
/* Copyright (c) 2026-present AeThex Labs.                                */
/**************************************************************************/

#include "aethex_parser.h"

bool AeThexParser::is_at_end() const {
	return current >= tokens.size() || tokens[current].type == AeThexTokenizer::TK_EOF;
}

AeThexTokenizer::Token AeThexParser::peek() const {
	if (current >= tokens.size()) {
		AeThexTokenizer::Token eof;
		eof.type = AeThexTokenizer::TK_EOF;
		return eof;
	}
	return tokens[current];
}

AeThexTokenizer::Token AeThexParser::previous() const {
	return tokens[current - 1];
}

AeThexTokenizer::Token AeThexParser::advance() {
	if (!is_at_end()) {
		current++;
	}
	return previous();
}

bool AeThexParser::check(AeThexTokenizer::TokenType type) const {
	if (is_at_end()) return false;
	return peek().type == type;
}

bool AeThexParser::match(AeThexTokenizer::TokenType type) {
	if (check(type)) {
		advance();
		return true;
	}
	return false;
}

void AeThexParser::consume(AeThexTokenizer::TokenType type, const String &message) {
	if (check(type)) {
		advance();
		return;
	}
	error(message);
}

void AeThexParser::error(const String &message) {
	ParseError err;
	err.message = message;
	err.line = peek().line;
	err.column = peek().column;
	errors.push_back(err);
}

void AeThexParser::synchronize() {
	advance();
	
	while (!is_at_end()) {
		if (previous().type == AeThexTokenizer::TK_NEWLINE) return;
		
		switch (peek().type) {
			case AeThexTokenizer::TK_REALITY:
			case AeThexTokenizer::TK_JOURNEY:
			case AeThexTokenizer::TK_BEACON:
			case AeThexTokenizer::TK_ARTIFACT:
			case AeThexTokenizer::TK_WHEN:
			case AeThexTokenizer::TK_TRAVERSE:
			case AeThexTokenizer::TK_WHILE:
			case AeThexTokenizer::TK_RETURN:
				return;
			default:
				break;
		}
		
		advance();
	}
}

Error AeThexParser::parse(const Vector<AeThexTokenizer::Token> &p_tokens) {
	tokens = p_tokens;
	current = 0;
	errors.clear();
	
	if (root) {
		memdelete(root);
		root = nullptr;
	}
	
	// Skip initial newlines
	while (match(AeThexTokenizer::TK_NEWLINE)) {}
	
	// Parse top-level reality block
	if (check(AeThexTokenizer::TK_REALITY)) {
		root = parse_reality();
	} else {
		error("Expected 'reality' block at start of file");
		return ERR_PARSE_ERROR;
	}
	
	if (!errors.is_empty()) {
		return ERR_PARSE_ERROR;
	}
	
	return OK;
}

AeThexParser::ASTNode *AeThexParser::parse_reality() {
	consume(AeThexTokenizer::TK_REALITY, "Expected 'reality'");
	
	ASTNode *node = memnew(ASTNode);
	node->type = ASTNode::NODE_REALITY;
	node->line = previous().line;
	
	// Get reality name
	consume(AeThexTokenizer::TK_IDENTIFIER, "Expected reality name");
	node->value = previous().value;
	
	// Parse block
	consume(AeThexTokenizer::TK_BRACE_OPEN, "Expected '{' after reality name");
	
	while (!check(AeThexTokenizer::TK_BRACE_CLOSE) && !is_at_end()) {
		// Skip newlines
		while (match(AeThexTokenizer::TK_NEWLINE)) {}
		
		if (check(AeThexTokenizer::TK_BRACE_CLOSE)) break;
		
		if (check(AeThexTokenizer::TK_JOURNEY)) {
			node->children.push_back(parse_journey());
		} else if (check(AeThexTokenizer::TK_BEACON)) {
			node->children.push_back(parse_beacon());
		} else if (check(AeThexTokenizer::TK_IDENTIFIER)) {
			// Attribute like "platforms: [...]"
			String attr_name = advance().value;
			consume(AeThexTokenizer::TK_COLON, "Expected ':' after attribute name");
			
			// Simple value parsing
			if (check(AeThexTokenizer::TK_BRACKET_OPEN)) {
				advance();
				String values;
				while (!check(AeThexTokenizer::TK_BRACKET_CLOSE) && !is_at_end()) {
					if (check(AeThexTokenizer::TK_IDENTIFIER)) {
						if (!values.is_empty()) values += ",";
						values += advance().value;
					}
					match(AeThexTokenizer::TK_COMMA);
				}
				consume(AeThexTokenizer::TK_BRACKET_CLOSE, "Expected ']'");
				node->attributes[attr_name] = values;
			} else if (check(AeThexTokenizer::TK_IDENTIFIER)) {
				node->attributes[attr_name] = advance().value;
			}
		} else {
			// Try to parse as statement
			ASTNode *stmt = parse_statement();
			if (stmt) {
				node->children.push_back(stmt);
			}
		}
	}
	
	consume(AeThexTokenizer::TK_BRACE_CLOSE, "Expected '}' after reality block");
	
	return node;
}

AeThexParser::ASTNode *AeThexParser::parse_journey() {
	consume(AeThexTokenizer::TK_JOURNEY, "Expected 'journey'");
	
	ASTNode *node = memnew(ASTNode);
	node->type = ASTNode::NODE_JOURNEY;
	node->line = previous().line;
	
	// Get function name
	consume(AeThexTokenizer::TK_IDENTIFIER, "Expected journey name");
	node->value = previous().value;
	
	// Parse parameters
	consume(AeThexTokenizer::TK_PAREN_OPEN, "Expected '(' after journey name");
	
	while (!check(AeThexTokenizer::TK_PAREN_CLOSE) && !is_at_end()) {
		if (check(AeThexTokenizer::TK_IDENTIFIER)) {
			ASTNode *param = memnew(ASTNode);
			param->type = ASTNode::NODE_IDENTIFIER;
			param->value = advance().value;
			node->children.push_back(param);
		}
		match(AeThexTokenizer::TK_COMMA);
	}
	
	consume(AeThexTokenizer::TK_PAREN_CLOSE, "Expected ')' after parameters");
	
	// Parse body
	consume(AeThexTokenizer::TK_BRACE_OPEN, "Expected '{' before journey body");
	
	while (!check(AeThexTokenizer::TK_BRACE_CLOSE) && !is_at_end()) {
		while (match(AeThexTokenizer::TK_NEWLINE)) {}
		
		if (check(AeThexTokenizer::TK_BRACE_CLOSE)) break;
		
		ASTNode *stmt = parse_statement();
		if (stmt) {
			node->children.push_back(stmt);
		}
	}
	
	consume(AeThexTokenizer::TK_BRACE_CLOSE, "Expected '}' after journey body");
	
	return node;
}

AeThexParser::ASTNode *AeThexParser::parse_beacon() {
	consume(AeThexTokenizer::TK_BEACON, "Expected 'beacon'");
	
	ASTNode *node = memnew(ASTNode);
	node->type = ASTNode::NODE_BEACON;
	node->line = previous().line;
	
	consume(AeThexTokenizer::TK_IDENTIFIER, "Expected beacon name");
	node->value = previous().value;
	
	// Parse parameters if present
	if (match(AeThexTokenizer::TK_PAREN_OPEN)) {
		while (!check(AeThexTokenizer::TK_PAREN_CLOSE) && !is_at_end()) {
			if (check(AeThexTokenizer::TK_IDENTIFIER)) {
				ASTNode *param = memnew(ASTNode);
				param->type = ASTNode::NODE_IDENTIFIER;
				param->value = advance().value;
				node->children.push_back(param);
			}
			match(AeThexTokenizer::TK_COMMA);
		}
		consume(AeThexTokenizer::TK_PAREN_CLOSE, "Expected ')' after beacon parameters");
	}
	
	return node;
}

AeThexParser::ASTNode *AeThexParser::parse_statement() {
	// Skip newlines
	while (match(AeThexTokenizer::TK_NEWLINE)) {}
	
	if (match(AeThexTokenizer::TK_LET) || match(AeThexTokenizer::TK_CONST)) {
		bool is_const = previous().type == AeThexTokenizer::TK_CONST;
		
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_VARIABLE;
		node->line = previous().line;
		node->attributes["const"] = is_const ? "true" : "false";
		
		consume(AeThexTokenizer::TK_IDENTIFIER, "Expected variable name");
		node->value = previous().value;
		
		if (match(AeThexTokenizer::TK_EQUAL)) {
			node->children.push_back(parse_expression());
		}
		
		return node;
	}
	
	if (match(AeThexTokenizer::TK_NOTIFY)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_NOTIFY;
		node->line = previous().line;
		node->children.push_back(parse_expression());
		return node;
	}
	
	if (match(AeThexTokenizer::TK_REVEAL)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_REVEAL;
		node->line = previous().line;
		if (!check(AeThexTokenizer::TK_NEWLINE) && !check(AeThexTokenizer::TK_BRACE_CLOSE)) {
			node->children.push_back(parse_expression());
		}
		return node;
	}
	
	if (match(AeThexTokenizer::TK_WHEN)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_IF;
		node->line = previous().line;
		
		// Condition
		node->children.push_back(parse_expression());
		
		// Then block
		consume(AeThexTokenizer::TK_BRACE_OPEN, "Expected '{' after when condition");
		ASTNode *then_block = memnew(ASTNode);
		then_block->type = ASTNode::NODE_LITERAL;
		then_block->value = "then";
		
		while (!check(AeThexTokenizer::TK_BRACE_CLOSE) && !is_at_end()) {
			while (match(AeThexTokenizer::TK_NEWLINE)) {}
			if (check(AeThexTokenizer::TK_BRACE_CLOSE)) break;
			ASTNode *stmt = parse_statement();
			if (stmt) then_block->children.push_back(stmt);
		}
		consume(AeThexTokenizer::TK_BRACE_CLOSE, "Expected '}' after when block");
		node->children.push_back(then_block);
		
		// Otherwise (else) block
		while (match(AeThexTokenizer::TK_NEWLINE)) {}
		if (match(AeThexTokenizer::TK_OTHERWISE)) {
			consume(AeThexTokenizer::TK_BRACE_OPEN, "Expected '{' after otherwise");
			ASTNode *else_block = memnew(ASTNode);
			else_block->type = ASTNode::NODE_LITERAL;
			else_block->value = "else";
			
			while (!check(AeThexTokenizer::TK_BRACE_CLOSE) && !is_at_end()) {
				while (match(AeThexTokenizer::TK_NEWLINE)) {}
				if (check(AeThexTokenizer::TK_BRACE_CLOSE)) break;
				ASTNode *stmt = parse_statement();
				if (stmt) else_block->children.push_back(stmt);
			}
			consume(AeThexTokenizer::TK_BRACE_CLOSE, "Expected '}' after otherwise block");
			node->children.push_back(else_block);
		}
		
		return node;
	}
	
	if (match(AeThexTokenizer::TK_SYNC)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_SYNC;
		node->line = previous().line;
		node->children.push_back(parse_expression());
		
		if (match(AeThexTokenizer::TK_ACROSS)) {
			if (match(AeThexTokenizer::TK_ALL)) {
				node->attributes["targets"] = "all";
			} else if (match(AeThexTokenizer::TK_BRACKET_OPEN)) {
				String targets;
				while (!check(AeThexTokenizer::TK_BRACKET_CLOSE) && !is_at_end()) {
					if (check(AeThexTokenizer::TK_IDENTIFIER)) {
						if (!targets.is_empty()) targets += ",";
						targets += advance().value;
					}
					match(AeThexTokenizer::TK_COMMA);
				}
				consume(AeThexTokenizer::TK_BRACKET_CLOSE, "Expected ']'");
				node->attributes["targets"] = targets;
			}
		}
		
		return node;
	}
	
	// Expression statement
	ASTNode *expr = parse_expression();
	return expr;
}

AeThexParser::ASTNode *AeThexParser::parse_expression() {
	return parse_assignment();
}

AeThexParser::ASTNode *AeThexParser::parse_assignment() {
	ASTNode *expr = parse_or();
	
	if (match(AeThexTokenizer::TK_EQUAL)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_ASSIGNMENT;
		node->line = previous().line;
		node->children.push_back(expr);
		node->children.push_back(parse_assignment());
		return node;
	}
	
	return expr;
}

AeThexParser::ASTNode *AeThexParser::parse_or() {
	ASTNode *left = parse_and();
	
	while (match(AeThexTokenizer::TK_OR)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_BINARY_OP;
		node->value = "or";
		node->line = previous().line;
		node->children.push_back(left);
		node->children.push_back(parse_and());
		left = node;
	}
	
	return left;
}

AeThexParser::ASTNode *AeThexParser::parse_and() {
	ASTNode *left = parse_equality();
	
	while (match(AeThexTokenizer::TK_AND)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_BINARY_OP;
		node->value = "and";
		node->line = previous().line;
		node->children.push_back(left);
		node->children.push_back(parse_equality());
		left = node;
	}
	
	return left;
}

AeThexParser::ASTNode *AeThexParser::parse_equality() {
	ASTNode *left = parse_comparison();
	
	while (match(AeThexTokenizer::TK_EQUAL_EQUAL) || match(AeThexTokenizer::TK_NOT_EQUAL)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_BINARY_OP;
		node->value = previous().type == AeThexTokenizer::TK_EQUAL_EQUAL ? "==" : "!=";
		node->line = previous().line;
		node->children.push_back(left);
		node->children.push_back(parse_comparison());
		left = node;
	}
	
	return left;
}

AeThexParser::ASTNode *AeThexParser::parse_comparison() {
	ASTNode *left = parse_term();
	
	while (match(AeThexTokenizer::TK_LESS) || match(AeThexTokenizer::TK_LESS_EQUAL) ||
		   match(AeThexTokenizer::TK_GREATER) || match(AeThexTokenizer::TK_GREATER_EQUAL)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_BINARY_OP;
		switch (previous().type) {
			case AeThexTokenizer::TK_LESS: node->value = "<"; break;
			case AeThexTokenizer::TK_LESS_EQUAL: node->value = "<="; break;
			case AeThexTokenizer::TK_GREATER: node->value = ">"; break;
			case AeThexTokenizer::TK_GREATER_EQUAL: node->value = ">="; break;
			default: break;
		}
		node->line = previous().line;
		node->children.push_back(left);
		node->children.push_back(parse_term());
		left = node;
	}
	
	return left;
}

AeThexParser::ASTNode *AeThexParser::parse_term() {
	ASTNode *left = parse_factor();
	
	while (match(AeThexTokenizer::TK_PLUS) || match(AeThexTokenizer::TK_MINUS)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_BINARY_OP;
		node->value = previous().type == AeThexTokenizer::TK_PLUS ? "+" : "-";
		node->line = previous().line;
		node->children.push_back(left);
		node->children.push_back(parse_factor());
		left = node;
	}
	
	return left;
}

AeThexParser::ASTNode *AeThexParser::parse_factor() {
	ASTNode *left = parse_unary();
	
	while (match(AeThexTokenizer::TK_STAR) || match(AeThexTokenizer::TK_SLASH) ||
		   match(AeThexTokenizer::TK_PERCENT)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_BINARY_OP;
		switch (previous().type) {
			case AeThexTokenizer::TK_STAR: node->value = "*"; break;
			case AeThexTokenizer::TK_SLASH: node->value = "/"; break;
			case AeThexTokenizer::TK_PERCENT: node->value = "%"; break;
			default: break;
		}
		node->line = previous().line;
		node->children.push_back(left);
		node->children.push_back(parse_unary());
		left = node;
	}
	
	return left;
}

AeThexParser::ASTNode *AeThexParser::parse_unary() {
	if (match(AeThexTokenizer::TK_NOT) || match(AeThexTokenizer::TK_MINUS)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_UNARY_OP;
		node->value = previous().type == AeThexTokenizer::TK_NOT ? "not" : "-";
		node->line = previous().line;
		node->children.push_back(parse_unary());
		return node;
	}
	
	return parse_call();
}

AeThexParser::ASTNode *AeThexParser::parse_call() {
	ASTNode *expr = parse_primary();
	
	while (true) {
		if (match(AeThexTokenizer::TK_PAREN_OPEN)) {
			ASTNode *node = memnew(ASTNode);
			node->type = ASTNode::NODE_CALL;
			node->line = previous().line;
			node->children.push_back(expr);
			
			// Arguments
			while (!check(AeThexTokenizer::TK_PAREN_CLOSE) && !is_at_end()) {
				node->children.push_back(parse_expression());
				match(AeThexTokenizer::TK_COMMA);
			}
			consume(AeThexTokenizer::TK_PAREN_CLOSE, "Expected ')' after arguments");
			expr = node;
		} else if (match(AeThexTokenizer::TK_DOT)) {
			ASTNode *node = memnew(ASTNode);
			node->type = ASTNode::NODE_MEMBER;
			node->line = previous().line;
			node->children.push_back(expr);
			
			consume(AeThexTokenizer::TK_IDENTIFIER, "Expected property name after '.'");
			ASTNode *member = memnew(ASTNode);
			member->type = ASTNode::NODE_IDENTIFIER;
			member->value = previous().value;
			node->children.push_back(member);
			expr = node;
		} else if (match(AeThexTokenizer::TK_BRACKET_OPEN)) {
			ASTNode *node = memnew(ASTNode);
			node->type = ASTNode::NODE_MEMBER;
			node->line = previous().line;
			node->children.push_back(expr);
			node->children.push_back(parse_expression());
			consume(AeThexTokenizer::TK_BRACKET_CLOSE, "Expected ']' after index");
			expr = node;
		} else {
			break;
		}
	}
	
	return expr;
}

AeThexParser::ASTNode *AeThexParser::parse_primary() {
	if (match(AeThexTokenizer::TK_TRUE)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_LITERAL;
		node->value = "true";
		node->line = previous().line;
		return node;
	}
	
	if (match(AeThexTokenizer::TK_FALSE)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_LITERAL;
		node->value = "false";
		node->line = previous().line;
		return node;
	}
	
	if (match(AeThexTokenizer::TK_NULL)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_LITERAL;
		node->value = "null";
		node->line = previous().line;
		return node;
	}
	
	if (match(AeThexTokenizer::TK_NUMBER)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_LITERAL;
		node->value = previous().value;
		node->attributes["type"] = "number";
		node->line = previous().line;
		return node;
	}
	
	if (match(AeThexTokenizer::TK_STRING) || match(AeThexTokenizer::TK_TEMPLATE_STRING)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_LITERAL;
		node->value = previous().value;
		node->attributes["type"] = "string";
		node->line = previous().line;
		return node;
	}
	
	if (match(AeThexTokenizer::TK_IDENTIFIER)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_IDENTIFIER;
		node->value = previous().value;
		node->line = previous().line;
		return node;
	}
	
	if (match(AeThexTokenizer::TK_SELF)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_IDENTIFIER;
		node->value = "self";
		node->line = previous().line;
		return node;
	}
	
	if (match(AeThexTokenizer::TK_PAREN_OPEN)) {
		ASTNode *expr = parse_expression();
		consume(AeThexTokenizer::TK_PAREN_CLOSE, "Expected ')' after expression");
		return expr;
	}
	
	if (match(AeThexTokenizer::TK_BRACKET_OPEN)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_ARRAY;
		node->line = previous().line;
		
		while (!check(AeThexTokenizer::TK_BRACKET_CLOSE) && !is_at_end()) {
			node->children.push_back(parse_expression());
			match(AeThexTokenizer::TK_COMMA);
		}
		consume(AeThexTokenizer::TK_BRACKET_CLOSE, "Expected ']' after array");
		return node;
	}
	
	if (match(AeThexTokenizer::TK_BRACE_OPEN)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_DICT;
		node->line = previous().line;
		
		while (!check(AeThexTokenizer::TK_BRACE_CLOSE) && !is_at_end()) {
			// Key
			ASTNode *key = parse_expression();
			consume(AeThexTokenizer::TK_COLON, "Expected ':' after dictionary key");
			ASTNode *value = parse_expression();
			
			node->children.push_back(key);
			node->children.push_back(value);
			match(AeThexTokenizer::TK_COMMA);
		}
		consume(AeThexTokenizer::TK_BRACE_CLOSE, "Expected '}' after dictionary");
		return node;
	}
	
	if (match(AeThexTokenizer::TK_NEW)) {
		ASTNode *node = memnew(ASTNode);
		node->type = ASTNode::NODE_CALL;
		node->value = "new";
		node->line = previous().line;
		
		consume(AeThexTokenizer::TK_IDENTIFIER, "Expected class name after 'new'");
		ASTNode *class_name = memnew(ASTNode);
		class_name->type = ASTNode::NODE_IDENTIFIER;
		class_name->value = previous().value;
		node->children.push_back(class_name);
		
		if (match(AeThexTokenizer::TK_PAREN_OPEN)) {
			while (!check(AeThexTokenizer::TK_PAREN_CLOSE) && !is_at_end()) {
				node->children.push_back(parse_expression());
				match(AeThexTokenizer::TK_COMMA);
			}
			consume(AeThexTokenizer::TK_PAREN_CLOSE, "Expected ')' after constructor arguments");
		}
		
		return node;
	}
	
	// No match - create an error node
	error("Expected expression");
	ASTNode *node = memnew(ASTNode);
	node->type = ASTNode::NODE_LITERAL;
	node->value = "";
	node->line = peek().line;
	advance();
	return node;
}