indexed_csv.hpp

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#pragma once
 
#include <csv.hpp>
 
#include <cstddef>
#include <cstdint>
#include <filesystem>
#include <functional>
#include <optional>
#include <string>
#include <string_view>
#include <unordered_map>
#include <vector>
 
namespace csvzall::viewer {
 
struct CsvRowIndexEntry {
  std::uint64_t byte_offset = 0;
};
 
struct CsvColumnDescriptor {
  std::string name;
  std::optional<std::size_t> source_index;
  std::string default_value;
};
 
struct CsvLogicalRow {
  std::optional<std::uint64_t> source_row;
  std::unordered_map<std::string, std::string> cells;
};
 
class CsvIndexedFile {
 public:
  static CsvIndexedFile Open(
      const std::string& input_path,
      csv::CSVFormat format,
      std::function<void(const std::string&)> verbose = {});
 
  [[nodiscard]] const std::string& input_path() const;
  [[nodiscard]] const std::string& file_name() const;
  [[nodiscard]] const std::vector<std::string>& headers() const;
  [[nodiscard]] std::uint64_t row_count() const;
  [[nodiscard]] std::uint64_t file_size() const;
 
  [[nodiscard]] std::vector<std::vector<std::string>> read_rows(
      std::uint64_t offset,
      std::uint64_t limit) const;
 
  void edit_cell(std::uint64_t row, const std::string& column, const std::string& value);
  void delete_row(std::uint64_t row);
  void insert_row(std::uint64_t row, const std::vector<std::string>& values);
  void swap_rows(std::uint64_t first, std::uint64_t second);
  void insert_column(std::uint64_t column, const std::string& name, const std::string& value);
  void rename_column(const std::string& column, const std::string& name);
  void delete_column(const std::string& column);
  bool recover_renamed_source();
  void reset();
  void save(const std::vector<std::string>& columns = {});
 
 private:
  [[nodiscard]] std::vector<std::vector<std::string>> read_source_rows(
      std::uint64_t offset,
      std::uint64_t limit) const;
  [[nodiscard]] std::vector<std::string> read_source_row(std::uint64_t source_row) const;
  [[nodiscard]] std::vector<std::string> row_values_for_columns(
      const CsvLogicalRow& row,
      const std::vector<CsvColumnDescriptor>& columns) const;
  [[nodiscard]] std::size_t column_index(const std::string& column) const;
  [[nodiscard]] bool has_column(const std::string& column) const;
  void refresh_headers();
  void validate_column_order(const std::vector<std::string>& columns) const;
  [[nodiscard]] std::vector<CsvColumnDescriptor> ordered_columns(
      const std::vector<std::string>& columns) const;
  void reload();
 
  std::string input_path_;
  std::string file_name_;
  std::vector<std::string> headers_;
  std::vector<CsvColumnDescriptor> columns_;
  std::vector<CsvRowIndexEntry> index_;
  std::vector<CsvLogicalRow> rows_;
  std::uint64_t file_size_ = 0;
  std::filesystem::file_time_type source_mtime_{};
  csv::CSVFormat format_;
};
 
enum class CsvViewDataMode {
  Paged,
};
 
class CsvViewData {
 public:
  static CsvViewData Open(
      const std::string& input_path,
      csv::CSVFormat format,
      std::function<void(const std::string&)> verbose = {});
 
  [[nodiscard]] CsvViewDataMode mode() const;
  [[nodiscard]] std::string_view mode_name() const;
  [[nodiscard]] const std::string& input_path() const;
  [[nodiscard]] const std::string& file_name() const;
  [[nodiscard]] const std::vector<std::string>& headers() const;
  [[nodiscard]] std::uint64_t row_count() const;
  [[nodiscard]] std::uint64_t file_size() const;
 
  [[nodiscard]] std::vector<std::vector<std::string>> read_rows(
      std::uint64_t offset,
      std::uint64_t limit) const;
 
  void edit_cell(std::uint64_t row, const std::string& column, const std::string& value);
  void delete_row(std::uint64_t row);
  void insert_row(std::uint64_t row, const std::vector<std::string>& values);
  void swap_rows(std::uint64_t first, std::uint64_t second);
  void insert_column(std::uint64_t column, const std::string& name, const std::string& value);
  void rename_column(const std::string& column, const std::string& name);
  void delete_column(const std::string& column);
  bool recover_renamed_source();
  void reset();
  void save(const std::vector<std::string>& columns = {});
 
 private:
  explicit CsvViewData(CsvIndexedFile indexed);
 
  CsvIndexedFile data_;
};
 
}  // namespace csvzall::viewer