#!/usr/bin/env python3
"""
Dump the structural schema of a compliance xlsx file as JSON.
Usage: python3 dump_xlsx_schema.py <path_to_xlsx>

Output:
{
  "sheets": [
    {
      "name": "SheetName",
      "columns": ["Col A", "Col B", ...],
      "row_count": 150,
      "metric_values": ["2.3.4i", "5.2.4", ...]   // only if a Metric column exists
    },
    ...
  ]
}

Dependencies: openpyxl (already in requirements.txt)
"""
import sys
import json
from openpyxl import load_workbook


def main():
    if len(sys.argv) < 2:
        print(json.dumps({'error': 'No file path provided'}))
        sys.exit(1)

    filepath = sys.argv[1]

    try:
        wb = load_workbook(filepath, read_only=True, data_only=True)
    except Exception as e:
        print(json.dumps({'error': f'Cannot open file: {str(e)}'}))
        sys.exit(1)

    sheets = []
    for sheet_name in wb.sheetnames:
        ws = wb[sheet_name]
        rows = list(ws.iter_rows(max_row=1, values_only=True))
        columns = [str(c).strip() for c in rows[0] if c is not None] if rows else []

        # Count data rows (excluding header)
        row_count = 0
        for _ in ws.iter_rows(min_row=2, values_only=True):
            row_count += 1

        # Extract metric values if a Metric column exists in the Summary sheet
        metric_values = []
        if sheet_name == 'Summary':
            # Summary has header at row 4 (0-indexed row 3), read from row 5 onward
            header_rows = list(ws.iter_rows(min_row=4, max_row=4, values_only=True))
            if header_rows:
                summary_cols = [str(c).strip() if c else '' for c in header_rows[0]]
                metric_idx = None
                for i, col in enumerate(summary_cols):
                    if col == 'Metric':
                        metric_idx = i
                        break
                if metric_idx is not None:
                    for row in ws.iter_rows(min_row=5, values_only=True):
                        if row[metric_idx] is not None:
                            val = str(row[metric_idx]).strip()
                            if val and val != 'Metric':
                                metric_values.append(val)

        entry = {
            'name': sheet_name,
            'columns': columns,
            'row_count': row_count,
        }
        if metric_values:
            entry['metric_values'] = sorted(set(metric_values))

        sheets.append(entry)

    wb.close()
    print(json.dumps({'sheets': sheets}, indent=2))


if __name__ == '__main__':
    main()