"""Read-only domain validation for review; commit also uses finance posting rules."""
from datetime import date
from finance.services.base import DomainError, money
from finance.models import Transaction


def validate(candidate, decision, account, refs, profile):
    issues = list(candidate.get("errors", []))
    if account is None:
        return issues + ["ACCOUNT_NOT_FOUND"]
    if account.archived:
        issues.append("ACCOUNT_ARCHIVED")
    if account.currency != "BRL":
        issues.append("UNSUPPORTED_CURRENCY")
    expected = "BANK" if profile == "BANK_CSV_V1" else "CREDIT_CARD"
    if account.kind != expected:
        issues.append("ACCOUNT_KIND_MISMATCH")
    if issues:
        return issues
    try:
        amount = money(candidate["amount"])
        date.fromisoformat(candidate["posting_date"])
    except (DomainError, ValueError, TypeError, KeyError):
        return ["INVALID_MOVEMENT"]
    kind = decision.get("kind", candidate["kind"])
    if kind not in {"INCOME", "EXPENSE", "REFUND", "TRANSFER"} or (kind in {"INCOME", "REFUND"} and amount <= 0) or (kind == "EXPENSE" and amount >= 0):
        issues.append("INVALID_KIND_OR_SIGN")
    for field, table in (("payee_id", "payees"), ("category_id", "categories")):
        if decision.get(field):
            ref = refs[table].get(decision[field])
            if ref is None or ref.archived:
                issues.append("INVALID_" + field.upper())
    category = refs["categories"].get(decision.get("category_id"))
    if category and category.kind != {"INCOME": "INCOME", "EXPENSE": "EXPENSE", "REFUND": "EXPENSE"}.get(kind):
        issues.append("CATEGORY_KIND_MISMATCH")
    statement = refs["statements"].get(decision.get("statement_id"))
    if decision.get("statement_id") and (statement is None or statement.account_id != account.pk or account.kind != "CREDIT_CARD"):
        issues.append("STATEMENT_ACCOUNT_MISMATCH")
    original = refs["transactions"].get(decision.get("refund_of_id"))
    if decision.get("refund_of_id") and (original is None or kind != "REFUND" or original.kind != "EXPENSE" or original.account.currency != account.currency):
        issues.append("INVALID_REFUND_REFERENCE")
    number, total = candidate.get("installment_number"), candidate.get("installment_total")
    if number is not None or total is not None:
        if not isinstance(number, int) or not isinstance(total, int) or not 1 <= number <= total or kind != "EXPENSE":
            issues.append("INVALID_INSTALLMENT")
        plan_id, new_plan = decision.get("installment_plan_id"), decision.get("new_plan")
        if bool(plan_id) == bool(new_plan):
            issues.append("INSTALLMENT_PLAN_REQUIRED")
        if plan_id:
            plan = refs["plans"].get(plan_id)
            if plan is None or plan.account_id != account.pk or plan.total_installments != total:
                issues.append("INSTALLMENT_PLAN_MISMATCH")
            elif decision.get("action") == "CREATE" and Transaction.objects.filter(installment_plan=plan, installment_number=number).exists():
                issues.append("INSTALLMENT_ALREADY_POSTED")
    elif decision.get("installment_plan_id") or decision.get("new_plan"):
        issues.append("UNEXPECTED_INSTALLMENT_PLAN")
    return issues