"""Response renderers.

Replaces renderers.js:
  - JSON_OUTPUT: JSON with 2-decimal float formatting + JSONP callback support
  - CSV_OUTPUT: semicolon-delimited CSV
"""

import csv
import io
import json

from flask import jsonify, Response


def json_output(ctx):
    """Render data as JSON.

    Replaces JSON_OUTPUT from renderers.js.
    Supports JSONP via ?callback= query parameter.
    Rounds floats to 2 decimal places.
    """
    data = ctx.get('data', {})

    def _replacer(val):
        if isinstance(val, float):
            return round(val, 2)
        return val

    json_data = json.dumps(data, default=_replacer, indent=2)

    from flask import request
    callback = request.args.get('callback')
    if callback:
        return Response(
            f'{callback}({json_data})',
            mimetype='application/javascript',
        )
    return Response(
        json_data,
        mimetype='application/json; charset=utf-8',
    )


def csv_output(ctx):
    """Render data as semicolon-delimited CSV.

    Replaces CSV_OUTPUT from renderers.js.
    """
    data = ctx.get('data', [])

    si = io.StringIO()
    writer = csv.writer(
        si,
        delimiter=';',
        lineterminator='\n',
    )

    if data and isinstance(data[0], dict):
        # Write header
        writer.writerow(data[0].keys())
        for row in data:
            writer.writerow(row.values())

    body = si.getvalue()
    si.close()

    return Response(
        body.encode('utf-8'),
        mimetype='text/csv; charset=utf-8',
    )