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


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

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

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