// SPDX-License-Identifier: MIT
#ifndef DBC_STATEMENT_HANDLER_H
#define DBC_STATEMENT_HANDLER_H

#include "dbc_database.h"
#include "dbc_diagnostic.h"
#include "typefactory.h"
#include <stdexcept>
#include <string>
#include <unordered_map>

struct PendingValueDescriptions {
    std::uint32_t canId;
    bool isExtended;
    std::string signalName;
    ValueDescriptions descriptions;
    std::size_t lineNumber;
};

struct PendingComment {
    std::uint32_t canId;
    bool isExtended;
    bool isSignal;
    std::string signalName;
    std::string comment;
    std::size_t lineNumber;
};

/** Carries deferred validation locations without parsing exception text. */
class DbcDiagnosticError : public std::runtime_error {
public:
    DbcDiagnosticError(DbcDiagnosticCode code, const std::string &filePath,
                       std::size_t lineNumber, const std::string &message)
        : std::runtime_error(filePath + ":" + std::to_string(lineNumber) + ": " + message),
          diagnostic{DbcDiagnosticSeverity::Error, code, filePath, lineNumber, message} {}

    DbcDiagnostic diagnostic;
};

/** Mutable state belonging to one file parse. Handlers do not retain it. */
struct DbcParseContext {
    DbcDatabase &database;
    FrameInfo *currentFrame = nullptr;
    std::size_t lineNumber = 0U;
    std::vector<PendingValueDescriptions> pendingValues = {};

    std::vector<std::vector<std::size_t>> signalLines = {};
    void ValidateMultiplexing(const std::string &filePath) const;

    std::vector<PendingComment> pendingComments = {};
    void ResolveComments(const std::string &filePath);

    void ResolveValueDescriptions(const std::string &filePath);
};

class DbcStatementHandler {
public:
    virtual ~DbcStatementHandler() = default;
    virtual void Handle(const std::string &line, DbcParseContext &context) const = 0;
};

class DbcFrameHandler : public DbcStatementHandler {
public:
    void Handle(const std::string &line, DbcParseContext &context) const override;

private:
    static FrameInfo ParseFrameLine(const std::string &line);
};

class DbcSignalHandler : public DbcStatementHandler {
public:
    void Handle(const std::string &line, DbcParseContext &context) const override;

private:
    static SignalInfo ParseSignalLine(const std::string &line);
};

class DbcCommentHandler : public DbcStatementHandler {
public:
    void Handle(const std::string &line, DbcParseContext &context) const override;

};

class DbcValueDescriptionHandler : public DbcStatementHandler {
public:
    void Handle(const std::string &line, DbcParseContext &context) const override;
};

class DbcUnsupportedMultiplexingHandler : public DbcStatementHandler {
public:
    void Handle(const std::string &line, DbcParseContext &context) const override;
};

/** Common header metadata does not change the supported decode definitions. */
class DbcHeaderHandler : public DbcStatementHandler {
public:
    void Handle(const std::string &line, DbcParseContext &context) const override;
};

/** Exact-key dispatch to handlers created once per registration via TypeFactory. */
class DbcStatementDispatcher {
public:
    DbcStatementDispatcher();

    template<class Handler>
    void RegisterType(const std::string &keyword) {
        m_factory.registerType<Handler>(keyword);
        m_handlers.insert_or_assign(keyword, m_factory.create(keyword));
    }

    /** Returns false for an unregistered keyword; input must be trimmed. */
    bool Dispatch(const std::string &line, DbcParseContext &context) const;

private:
    using HandlerMap = std::unordered_map<std::string, std::shared_ptr<DbcStatementHandler>>;
    TypeFactory<std::string, DbcStatementHandler> m_factory;
    HandlerMap m_handlers;
};

#endif /* DBC_STATEMENT_HANDLER_H */