#ifndef COMDEL_PARSER_H
#define COMDEL_PARSER_H

#include "source_error.h"
#include "presult.h"
#include "token.h"
#include "ast_nodes.h"

#include <optional>
#include <set>
#include <vector>

/// Records the current span and can later be called on
/// an ast node to apply the entire span to that node
///
/// Spanner's call operator MOVES from the node so it should
/// be always used last.
class Spanner {
    // REFERENCE to the parser's prevSpan. After parsing a node this will
    // "point" to the span of the last token contained in the node.
    const Span &prevSpan;

public:
    const Span lo; // the low end of the span, beginning of the node

    Spanner(Span lo, Span &prevSpan) : lo(lo), prevSpan(prevSpan) {}

    template<typename T, typename = std::enable_if<std::is_base_of<AstNode, T>::value>>
    typename std::remove_reference_t<T> operator()(T &&astNode) const {
        astNode.span = lo.to(prevSpan);
        return std::forward<T>(astNode);
    }
};

class ComdelParser {
private:
    std::vector<Token> tokens;
    std::set<TokenType> expectedTokens;

    unsigned int position;
    std::vector<SourceError> errors;

    Span &getPreviousSpan();

    void bump();

    bool consume(TokenType tokenType);

    bool check(TokenType tokenType);

    void skipUntilNextKeyword();

    Token &current();

    [[nodiscard]] PError unexpected();

    template<typename T>
    PResult<std::vector<T>> parseList(std::optional<TokenType> openDelim,
                                      TokenType closeDelim,
                                      std::optional<TokenType> separator,
                                      bool allowTrailing,
                                      const std::function<PResult<T>()> &parse_f);

    Spanner getSpanner();

    // used to parse library and schema
    PResult<StringNode> parseString();

    PResult<IdentifierNode> parseIdentifier();

    PResult<NumberNode> parseNumber();

    PResult<CountNode> parseCount();

    PResult<PropertyNode> parseProperty(std::optional<TokenType> valueType);

    PResult<EnumerationNode> parseEnumeration();

    PResult<ValueNode> parseConnectionWire();

    PResult<ComponentNode> parseComponent();

    PResult<AddressSpaceNode> parseAddress();

    PResult<PinNode> parsePin();

    PResult<DisplayNode> parseDisplay();

    PResult<PinConnectionNode> parsePinConnection();

    PResult<AttributeNode> parseAttribute();

    PResult<PopupNode> parsePopup();

    PResult<RuleNode> parseRule();

    PResult<BusNode> parseBus();

    PResult<WireNode> parseWire();

    PResult<ConnectionNode> parseConnection();

    PResult<DisplayItemNode> parseDisplayItem();

    PResult<IfStatementNode> parseIfStatement();

    PResult<ValueNode> parseValue();

    // used to parse schema
    PResult<CountNode> parsePosition();

    PResult<InstanceNode> parseInstance();

    PResult<InstanceAttributeNode> parseInstanceAttribute();

    PResult<ConnectionInstanceNode> parseConnectionInstance();

    PResult<EnumNode<ComponentNode::ComponentType>> parseComponentType();

    PResult<EnumNode<BusNode::BusType>> parseBusType();

    PResult<EnumNode<PinConnectionNode::ConnectionType>> parseConnectionType();

public:
    explicit ComdelParser(std::vector<Token> tokens);

    std::optional<SchemaNode> parseSchema();

    std::optional<LibraryNode> parseLibrary();

    const std::vector<SourceError> &getErrors();
};

#endif // COMDEL_PARSER_H