usql/parser.h

#pragma once

#include "lexer.h"
#include <stdexcept>
#include <string>

#include <vector>


enum class ColumnType {
	integer_type,
	float_type,
	varchar_type
};

enum class NodeType {
    true_node,
    int_value,
    float_value,
    string_value,
    database_value,
    logical_operator,
    relational_operator,
	create_table,
	insert_into,
	select_from,
    column_name,
	column_value,
	column_def,
	not_implemented_yet,
	error
};

struct Node {
	NodeType node_type;

	Node(const NodeType type) : node_type(type) {}
};

struct ColNameNode : Node {
    std::string	name;

    ColNameNode(const std::string col_name) :
            Node(NodeType::column_name), name(col_name) {}
};

struct ColValueNode : Node {
    std::string	value;

    ColValueNode(const std::string col_value) :
            Node(NodeType::column_value), value(col_value) {}
};

// TODO add order in row
struct ColDefNode : Node {
	std::string	name;
	ColumnType	type;
	int         order;
	int 		length;
	bool		null;

	ColDefNode(const std::string col_name, const ColumnType col_type, int col_order, int col_len, bool nullable) :
		Node(NodeType::column_def), name(col_name), type(col_type), order(col_order), length(col_len), null(nullable) {}
};

struct  TrueNode : Node {
    TrueNode() : Node(NodeType::true_node) {}
};

struct  IntValueNode : Node {
    int    value;

    IntValueNode(int value) : Node(NodeType::int_value), value(value) {}
};

struct  FloatValueNode : Node {
    double    value;

    FloatValueNode(double value) : Node(NodeType::float_value), value(value) {}
};

struct  StringValueNode : Node {
    std::string     value;

    StringValueNode(std::string value) : Node(NodeType::string_value), value(value) {}
};

struct  DatabaseValueNode : Node {
    std::string     col_name;

    DatabaseValueNode(std::string name) : Node(NodeType::database_value), col_name(name) {}
};

struct LogicalOperatorNode : Node {
//    and_operator,
//    or_operator,
//    not_operator,
    // and / or / not
    std::unique_ptr<Node> left;
    std::unique_ptr<Node> right;
};

enum class RelationalOperatorType {
    equal,
    greater
    // =, !=, >, >=, <, <=, like
};

struct RelationalOperatorNode : Node {
    RelationalOperatorType  op;

    std::unique_ptr<Node> left;
    std::unique_ptr<Node> right;

    RelationalOperatorNode(RelationalOperatorType op, std::unique_ptr<Node> left, std::unique_ptr<Node> right) :
        Node(NodeType::relational_operator), op(op), left(std::move(left)), right(std::move(right)) {};
};

struct CreateTableNode : Node {
	std::string table_name;
	std::vector<ColDefNode> cols_defs;

	CreateTableNode(const std::string name, std::vector<ColDefNode> defs) :
		Node(NodeType::create_table), table_name(name), cols_defs(defs) {}
};

struct InsertIntoTableNode : Node {
    std::string table_name;
    std::vector<ColNameNode> cols_names;
    std::vector<ColValueNode> cols_values;

    InsertIntoTableNode(const std::string name, std::vector<ColNameNode> names, std::vector<ColValueNode> values) :
            Node(NodeType::insert_into), table_name(name), cols_names(names), cols_values(values) {}
};

struct SelectFromTableNode : Node {
    std::string table_name;
    std::vector<ColNameNode> cols_names;
    std::unique_ptr<Node> where;

    SelectFromTableNode(const std::string name, std::vector<ColNameNode> names, std::unique_ptr<Node> where_clause) :
            Node(NodeType::select_from), table_name(name), cols_names(names), where(std::move(where_clause)) {}
};

struct UpdateTableNode : Node { };
struct DeleteFromTableNode : Node { };




class Parser {
private:

public:
	Parser();

	std::unique_ptr<Node> parse(const std::string &code);

private:
    std::unique_ptr<Node> parse_create_table();
    std::unique_ptr<Node> parse_insert_into_table();
    std::unique_ptr<Node> parse_select_from_table();

    std::unique_ptr<Node> parse_where_clause();
    std::unique_ptr<Node> parse_operand_node();
    RelationalOperatorType parse_operator();

private:
	Lexer lexer;
};