csv_loader.hpp

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#pragma once
 
#include <cstdint>
#include <functional>
#include <ostream>
#include <string>
#include <vector>
 
// Forward declarations — consumers that need to call db methods must include
// the full SQLiteCpp and csv-parser headers themselves.
namespace csv { class CSVReader; }
namespace SQLite {
class Database;
class Statement;
}
 
namespace csvzall::sqlite {
 
struct SqliteLogCallbacks {
  std::function<void(const std::string&)> error;
  std::function<void(const std::string&)> verbose;
};
 
struct CsvLoadOptions {
  bool sqlite_journal_enabled = false;
};
 
enum class SqliteColumnAffinity {
  Numeric,
  Text,
};
 
// Returns a double-quoted SQL identifier with embedded '"' escaped by doubling.
// E.g. my"col  →  "my""col"
// Use this wherever column or table names appear in generated SQL.
std::string QuoteIdentifier(const std::string& name);
 
// Infer SQLite column affinities from the remaining rows in reader.
//
// Numeric columns stay NUMERIC so SQL comparisons and arithmetic keep working.
// Columns with text, booleans, timestamps, or CSV_BIGINT values become TEXT so
// projections preserve exact lexical cell values such as long identifier IDs.
std::vector<SqliteColumnAffinity> InferColumnAffinities(
    csv::CSVReader& reader,
    const std::vector<std::string>& headers);
 
// Load all rows from reader into a newly-created SQLite table.
//
// Schema conventions:
//   - Column affinity is supplied by the caller, normally from
//     InferColumnAffinities() followed by a reader reset. NUMERIC columns let
//     SQLite compare numeric values naturally; TEXT columns preserve exact CSV
//     cells for identifiers and mixed/non-numeric data.
//   - Column names are double-quoted in generated DDL; embedded " are escaped
//     by doubling ("my""col").
//
// Parameters:
//   reader      — positioned after the header row (csv-parser has parsed it).
//   headers     — the column names to use; must match the row field count.
//   db          — open, writable SQLite::Database.
//   table_name  — name of the table to create (must not already exist).
//   logger      — error/verbose callbacks; only error is used on failure.
//
// Returns true on success, false on any SQLite or structural error.
bool LoadCsvIntoTable(csv::CSVReader& reader,
                      const std::vector<std::string>& headers,
                      SQLite::Database& db,
                      const std::string& table_name,
                      const std::vector<SqliteColumnAffinity>& column_affinities,
                      const CsvLoadOptions& options,
                      const SqliteLogCallbacks& logger);
 
bool LoadCsvIntoTableWithInferredAffinities(
    const std::function<csv::CSVReader&()>& reader,
    const std::vector<std::string>& headers,
    SQLite::Database& db,
    const std::string& table_name,
    const std::function<bool()>& reset_reader,
    const CsvLoadOptions& options,
    const SqliteLogCallbacks& logger);
 
std::vector<std::string> StatementColumnNames(SQLite::Statement& statement);
std::vector<std::string> StatementRowValues(SQLite::Statement& statement);
 
std::uint64_t WriteStatementRowsAsCsv(SQLite::Statement& statement,
                                      const std::vector<std::string>& headers,
                                      std::ostream& output);
 
}  // namespace csvzall::sqlite
 
namespace csvzall::pipeline {
namespace sqlite = ::csvzall::sqlite;
}