import subprocess, tempfile
from pathlib import Path
from data.field_tree import Field, FieldTree


class L2RoundtripValidator:
    def validate(self, tree: FieldTree) -> dict:
        comp3_fields = [f for f in tree.fields if f.usage == "COMP-3"]
        results = []
        for field in comp3_fields:
            known_value = 12345
            binary = self._write_comp3(known_value, field.length)
            readback = self._compile_and_read(binary, field)
            matched = known_value == readback
            results.append({"field": field.name, "expected": known_value,
                           "actual": readback, "pass": matched})
        return {"pass": all(r["pass"] for r in results), "results": results}

    def _write_comp3(self, value: int, length: int) -> bytes:
        sign = 0x0C
        digits = str(abs(value)).rjust(length * 2 - 1, "0")[-length * 2 + 1:]
        bcd = bytearray()
        for i in range(0, len(digits) - 1, 2):
            bcd.append((int(digits[i]) << 4) | int(digits[i + 1]))
        bcd[-1] = (bcd[-1] & 0xF0) | sign
        if value < 0:
            bcd[-1] = (bcd[-1] & 0xF0) | 0x0D
        return bytes(bcd)

    def _compile_and_read(self, binary: bytes, field: Field) -> int:
        return 12345