csv-handler

# CSV Handler for Construction Data

## Overview
CSV is the universal exchange format in construction - from scheduling exports to cost databases. This skill handles encoding issues, delimiter detection, and data cleaning.

## Python Implementation

```python
import pandas as pd
import csv
from typing import Dict, Any, List, Optional, Tuple
from pathlib import Path
from dataclasses import dataclass
import chardet


@dataclass
class CSVProfile:
    """Profile of CSV file."""
    encoding: str
    delimiter: str
    has_header: bool
    row_count: int
    column_count: int
    columns: List[str]


class ConstructionCSVHandler:
    """Handle CSV files from construction software."""

    COMMON_DELIMITERS = [',', ';', '\t', '|']
    COMMON_ENCODINGS = ['utf-8', 'utf-8-sig', 'latin-1', 'cp1252', 'iso-8859-1']

    def __init__(self):
        self.last_profile: Optional[CSVProfile] = None

    def detect_encoding(self, file_path: str) -> str:
        """Detect file encoding."""
        with open(file_path, 'rb') as f:
            raw = f.read(10000)
        result = chardet.detect(raw)
        return result.get('encoding', 'utf-8') or 'utf-8'

    def detect_delimiter(self, file_path: str, encoding: str) -> str:
        """Detect CSV delimiter."""
        with open(file_path, 'r', encoding=encoding, errors='replace') as f:
            sample = f.read(5000)

        # Count occurrences
        counts = {d: sample.count(d) for d in self.COMMON_DELIMITERS}

        # Return most common that appears consistently
        if counts:
            return max(counts, key=counts.get)
        return ','

    def profile_csv(self, file_path: str) -> CSVProfile:
        """Profile CSV file."""
        encoding = self.detect_encoding(file_path)
        delimiter = self.detect_delimiter(file_path, encoding)

        # Read sample
        df = pd.read_csv(file_path, encoding=encoding, delimiter=delimiter,...