import yaml
from dataclasses import dataclass, field
from pathlib import Path


@dataclass
class FieldMapping:
    cobol_field: str
    java_field: str
    field_type: str = "string"
    precision: int = 0
    trim: bool = False
    format: str = ""
    init_strategy: str = "auto"


@dataclass
class MappingConfig:
    program: str = ""
    dialect: str = "ibm"
    field_mappings: list[FieldMapping] = field(default_factory=list)
    redefines_strategy: dict = field(default_factory=dict)

    @classmethod
    def from_yaml(cls, path: str) -> "MappingConfig":
        data = yaml.safe_load(Path(path).read_text())
        c = cls()
        c.program = data.get("program", "")
        c.dialect = data.get("dialect", "ibm")
        for fm in data.get("field_mapping", []):
            c.field_mappings.append(FieldMapping(**fm))
        c.redefines_strategy = data.get("redefines_strategy", {})
        return c

    def get_java_field(self, cobol_name: str) -> str:
        for m in self.field_mappings:
            if m.cobol_field == cobol_name:
                return m.java_field
        return cobol_name


_m = FieldMapping(cobol_field="BR-AMT", java_field="billAmount", field_type="decimal", precision=2)
assert _m.cobol_field == "BR-AMT"