id = "entry-a-line-amount-is-positive"
title = "A negative or zero line amount is refused; the side gives the direction"
rule = "A line's amount MUST be greater than zero, and its side, not its sign, MUST give the direction money moves; an entry with a negative or zero line MUST be refused."
status = "CONVENTION"
sources = [
  "Pacioli, Summa (1494), ch. 36: debtors at the left, creditors at the right (docs/spec/sources/pacioli-1494.md)",
  "CONVENTION, the owner, 2026-10-13 (docs/spec/rules.md B-2): no authority forbids a negative amount outright; one reading of every line is chosen",
]
tags = ["accrual", "book", "us", "entry"]

[setup]
currency = "USD"
fiscal_year_start = "01-01"
basis = "accrual"
rounding = "half-even"

[[setup.accounts]]
code = "1000"
name = "Cash"
type = "asset"

[[setup.accounts]]
code = "3000"
name = "Capital"
type = "equity"

[[setup.accounts]]
code = "4000"
name = "Sales"
type = "revenue"
tax_category = "gross_receipts"

[[setup.accounts]]
code = "6000"
name = "Rent"
type = "expense"
tax_category = "rent_property"

# A credit of minus 100.00 would be a debit of 100.00 written the other
# way; the books keep one way to write it.
[[events]]
date = "2026-01-05"
description = "A negative credit"
refused = "negative_amount"
lines = [
  { account = "1000", side = "debit", amount = "100.00" },
  { account = "4000", side = "credit", amount = "-100.00" },
]

[[events]]
date = "2026-01-06"
description = "A zero line"
refused = "zero_amount"
lines = [
  { account = "1000", side = "debit", amount = "0.00" },
  { account = "4000", side = "credit", amount = "0.00" },
]

# The same 100.00 written with the sides doing the work is accepted.
[[events]]
date = "2026-01-07"
description = "A sale"
lines = [
  { account = "1000", side = "debit", amount = "100.00" },
  { account = "4000", side = "credit", amount = "100.00" },
]

[[expect]]
query = "trial_balance"
as_of = "2026-12-31"
[expect.values]
"1000" = "100.00"
"3000" = "0.00"
"4000" = "-100.00"
"6000" = "0.00"