Parse and Filter Chargeback Disputes

Implement parseChargebacks(rows) to parse dated network chargeback files, ignore invalid data rows, and remove disputes withdrawn in a strictly later file. Return the remaining dispute rows. The requirements build on one another: Part 1 parses and formats valid records; Part 2 filters invalid records; Part 3 also handles withdrawals. Implement the complete Part 3 behavior.

File layout

The array flattens 1 through 10 files. Each file begins with NETWORK_yyyymmdd.csv, then a header, then at most 50 data rows. NETWORK is always uppercase and is one of VISA, PAYPAL, AMEX, or JCB. Files may appear in any date order. A new filename starts the next file.

Every header contains exactly these six names in any order:

transaction,merchant,amount,currency,evidence_due_by,reason

Interpret each data row using its own file's header. transaction identifies the disputed transaction on that network; merchant identifies its merchant; amount is in minor currency units; currency is the currency code; evidence_due_by is the merchant's evidence deadline as a UNIX timestamp; reason identifies the reason for the dispute.

Invalid rows

Ignore a data row if its currency is unsupported, its amount is not a positive integer, or its evidence deadline is not a whole number. Supported currencies are EUR, USD, SGD, BRL, JPY, ISK, and KRW. Ignore only that row.

For this practice version, a whole-number field must be a nonempty sequence of ASCII digits. Leading zeros are allowed. A valid amount is from 1 through 1000000000, and a valid deadline is from 0 through 9223372036854775807, inclusive. Out-of-range values are invalid. Do not trim fields; signs, spaces, and decimal points are not digits.

Withdrawals

A valid row whose reason is exactly withdrawn is a withdrawal; every other valid row is a normal dispute. A valid withdrawal cancels a normal dispute only when their network and transaction ID match and the withdrawal's filename date is strictly later than the normal row's filename date. The evidence deadline and the order of files in the array do not determine cancellation.

An invalid withdrawal, or a withdrawal with no earlier matching normal dispute on that network, is ignored. An earlier or same-date withdrawal does not cancel a normal dispute. If both rows are invalid, ignore both. Never return a withdrawal row.

A transaction may appear in at most two files for each network and may be withdrawn at most once. For this practice version, repeated normal rows within a file are allowed: keep every valid normal row unless a qualifying withdrawal cancels it. A withdrawal can therefore cancel several earlier normal rows.

Output

Return one string for each surviving normal row, with four comma-separated fields in this order:

dispute_id,merchant,value,evidence_due_by

• dispute_id concatenates the uppercase network and the original transaction ID without a separator.
• Copy the merchant and the deadline text from that normal row exactly, including any leading zeros in the deadline.
• For EUR, USD, SGD, and BRL, divide the amount by 100 to get major units. For JPY, ISK, and KRW, one minor unit is one major unit.
• Always use a period and exactly two digits after it, then append the currency code. For example, 1 minor unit becomes 0.01USD or 1.00JPY.

Sort by the concatenated dispute ID in ascending lexicographic order. For this practice version, equal IDs preserve the original data-row order. Return an empty array if no normal disputes remain.