import struct, json
from pathlib import Path
from data.test_case import TestCase, SparkConfig


class DataWriter:
    def write_cobol_binary(self, test_cases: list[TestCase], output: Path):
        with open(output, "wb") as f:
            for tc in test_cases:
                for name, value in tc.fields.items():
                    if isinstance(value, int):
                        f.write(struct.pack(">q", value))
                    elif isinstance(value, float):
                        f.write(struct.pack(">d", value))
                    elif isinstance(value, str):
                        encoded = value.encode("ascii", errors="replace")
                        f.write(encoded.ljust(10, b" ")[:10])

    def write_spark_json(self, test_cases: list[TestCase], spark_config: SparkConfig,
                         output_dir: Path):
        output_dir.mkdir(parents=True, exist_ok=True)
        base = test_cases[0].fields if test_cases else {}
        records = []
        for i in range(spark_config.num_records):
            record = dict(base)
            if spark_config.key_field and spark_config.key_field in record:
                record[spark_config.key_field] = f"{record[spark_config.key_field]}-{i:04d}"
            records.append(record)
        (output_dir / "part-00000.json").write_text("\n".join(json.dumps(r) for r in records))

    def write_native_json(self, test_cases: list[TestCase], output: Path):
        output.parent.mkdir(parents=True, exist_ok=True)
        with open(output, "w") as f:
            for tc in test_cases:
                f.write(json.dumps(tc.fields) + "\n")