#pragma once

#include <optional>
#include <unordered_map>

#include <Core/Block.h>
#include <Processors/Formats/RowInputFormatWithDiagnosticInfo.h>
#include <Formats/FormatSettings.h>


namespace DB
{

/** A stream for inputting data in csv format.
  * Does not conform with https://tools.ietf.org/html/rfc4180 because it skips spaces and tabs between values.
  */
class CSVRowInputFormat : public RowInputFormatWithDiagnosticInfo
{
public:
    /** with_names - in the first line the header with column names
      */
    CSVRowInputFormat(const Block & header_, ReadBuffer & in_, const Params & params_,
                      bool with_names_, const FormatSettings & format_settings_);

    String getName() const override { return "CSVRowInputFormat"; }

    bool readRow(MutableColumns & columns, RowReadExtension & ext) override;
    void readPrefix() override;
    bool allowSyncAfterError() const override { return true; }
    void syncAfterError() override;
    void resetParser() override;

private:
    bool with_names;
    const FormatSettings format_settings;
    DataTypes data_types;

    using IndexesMap = std::unordered_map<String, size_t>;
    IndexesMap column_indexes_by_names;

    /// Maps indexes of columns in the input file to indexes of table columns
    using OptionalIndexes = std::vector<std::optional<size_t>>;
    OptionalIndexes column_indexes_for_input_fields;

    /// Tracks which columns we have read in a single read() call.
    /// For columns that are never read, it is initialized to false when we
    /// read the file header, and never changed afterwards.
    /// For other columns, it is updated on each read() call.
    std::vector<UInt8> read_columns;

    /// Whether we have any columns that are not read from file at all,
    /// and must be always initialized with defaults.
    bool have_always_default_columns = false;

    void addInputColumn(const String & column_name);

    bool parseRowAndPrintDiagnosticInfo(MutableColumns & columns, WriteBuffer & out) override;
    void tryDeserializeFiled(const DataTypePtr & type, IColumn & column, size_t file_column,
                             ReadBuffer::Position & prev_pos, ReadBuffer::Position & curr_pos) override;
    bool isGarbageAfterField(size_t, ReadBuffer::Position pos) override
    {
        return *pos != '\n' && *pos != '\r' && *pos != format_settings.csv.delimiter;
    }

    bool readField(IColumn & column, const DataTypePtr & type, bool is_last_file_column);
};

}