from data.diff_result import FieldResult
from decimal import Decimal, InvalidOperation

DEFAULT_TOLERANCE = 0.01


def compare_field(name: str, c: str, j: str, field_type: str = "decimal",
                  tolerance: float = DEFAULT_TOLERANCE) -> FieldResult:
    fr = FieldResult(field_name=name, cobol_value=c, java_value=j)

    if field_type in ("decimal", "numeric"):
        return _numeric(fr, c, j, tolerance)
    if field_type == "date":
        return _date(fr, c, j)
    if field_type == "string":
        return _string(fr, c, j)
    fr.status = "PASS" if c == j else "MISMATCH"
    return fr


def _numeric(fr, c, j, tol):
    cv = _num(c)
    jv = _num(j)
    if cv is None or jv is None:
        fr.status = "NOT_SET" if cv is None and jv is None else (
            "MISMATCH" if jv is None else "NOT_SET")
        return fr
    if cv == jv:
        fr.status = "PASS"
        return fr
    diff = abs(float(cv - jv))
    if diff <= tol:
        fr.status = "TOLERATED"
        fr.tolerance_applied = tol
    else:
        fr.status = "MISMATCH"
    return fr


def _date(fr, c, j):
    def _norm(v):
        v = v.strip()
        if len(v) == 8 and v.isdigit():
            return f"{v[:4]}-{v[4:6]}-{v[6:8]}"
        return v
    fr.status = "PASS" if _norm(c) == _norm(j) else "MISMATCH"
    return fr


def _string(fr, c, j):
    fr.status = "PASS" if (c or "").strip() == (j or "").strip() else "MISMATCH"
    return fr


def _num(v):
    if v is None or v == "None":
        return None
    s = str(v).replace("\x00", "").strip()
    if s == "":
        return Decimal("0")
    try:
        return Decimal(s)
    except InvalidOperation:
        return None