Files
money/CLAUDE.md
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nikolaandClaude Opus 5 83d842d92e Let rules carry a note
A glob like *4412* says nothing about why it exists or who it catches, and
six months later neither does memory. Rules get an optional note: free text
that never takes part in matching, written as a TOML key rather than a
comment so it survives a round trip and can be shown back.

The rule builder grows a fourth field for it and the rules screen a last
column. Four fields spaced out are taller than a short window has room for,
so the form now drops its blank lines and then the hints on unfocused fields
before anything would run off the bottom.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-09 23:23:29 +02:00

138 lines
6.5 KiB
Markdown

# money
Statement-driven personal finance tracker. A data directory holds one folder per
account; statements dropped into those folders are parsed into a rebuildable
SQLite index, categorised by ordered glob rules, and browsed in a Bubble Tea TUI.
Read `README.md` first — it is the user-facing reference for every config key.
This file covers what the code assumes and why.
## Layout
```
cmd/money/main.go subcommands; the TUI is the default
internal/config rules.toml, account.toml, XDG config, data-root resolution
internal/model Account, Transaction, amount formatting, description normalisation
internal/glob the `*` / `?` matcher used by rules (linear time, no backtracking)
internal/parser Parser interface + registry; csv, cmd, nlb, revolut, traderepublic
internal/store SQLite index (modernc.org/sqlite, no cgo)
internal/importer directory walk, dedupe, balance checks
internal/rules applies ordered rules to rule_* columns only
internal/report per-tag aggregation, transfers excluded
internal/tui Bubble Tea models
```
## Invariants
**Rule verdicts and manual edits never share a column.** `rule_tag` /
`rule_transfer` are rewritten wholesale on every retag; `manual_tag` /
`manual_transfer` are only ever written by the user. Effective values are
`COALESCE(manual_*, rule_*)`. This is what makes `money retag` safe to run at
any time, and it is the first thing to preserve when touching the schema or the
rules engine. Covered by `TestManualTagSurvivesRetag`.
**Statements are the source of truth; the index is disposable.** Deleting
`.money/index.db` and re-importing must reproduce everything except manual tags
and manual transfer marks.
**Dedupe is by fingerprint**: `sha256(date | amount | normalised description |
ordinal)`, where the ordinal distinguishes identical lines *within one
statement*. Two identical purchases on one day both survive; the same line in an
overlapping statement does not duplicate. Unchanged files are skipped by
checksum before parsing at all — so an import with nothing new finishes in
milliseconds. That is the checksum skip working, not a failure.
**Money is `int64` minor units**, never a float. Per-account currency, no
conversion, and totals are never summed across currencies.
**First matching rule wins**, so transfer rules belong above general tag rules.
A rule setting several of `match` / `counterparty` / `type` requires all of them.
`config.AppendRule` therefore appends — never prepends — so saving from the
rule builder cannot shadow a rule the user wrote by hand.
**The rule builder is a form, so the global keymap must not apply there.**
`Update` routes to `updateRules` before `updateNormal` whenever the view is
`viewRules`, or typing `q` would quit and `i` would start an import. Any new
full-screen input needs the same treatment.
**In the rule builder, `tab` completes first and moves focus second.** The
account and tag fields use `textinput.ShowSuggestions`, whose own `AcceptSuggestion`
key is `tab` and whose `NextSuggestion`/`PrevSuggestion` are `up`/`down` — all
three already meant something here. So `updateRules` intercepts `tab` and calls
`acceptCompletion` before falling back to `setRuleFocus`, keeps `up`/`down` on
field navigation, and lets `ctrl+n` / `ctrl+p` through to the input for cycling.
`SetValue` does not re-match the suggestion list, so `acceptCompletion` re-sets
it afterwards or `ctrl+n` would offer candidates that no longer fit the value.
**A rule's usage count is how many transactions it wins, not how many its glob
could match** — `Engine.Usage` counts by `MatchIndex`, so a rule shadowed by an
earlier one correctly reports zero. That is what makes the rules screen able to
find dead rules at all.
**A rule's `note` is documentation that round-trips.** It is a TOML key rather
than a `#` comment so `LoadRules` can return it, the builder can write it and
the rules screen can show it. It never takes part in matching — `rules.Engine`
does not look at it — and it must stay that way.
**`config.DeleteRules` edits rules.toml textually, never by re-serialising the
parsed rules**, because comments and formatting are not recoverable from
`[]Rule`. A rule owns the comment lines directly above it; a comment separated
by a blank line is a heading for what follows and stays. Both writers go
through `writeFileAtomic`, and deletion re-parses the result before replacing
the file.
## Adding a bank parser
Implement `parser.Parser` and call `parser.Register` from an `init`. Nothing
else changes; the name becomes usable in an `account.toml`. Use
`parser.ParseAmount` rather than hand-rolling decimal handling — it copes with
`1.234,56`, trailing minus, parenthesised negatives, currency codes and both
the ASCII hyphen and U+2212.
Keep PDF text extraction separate from parsing: the bank parsers expose a pure
`parseXText(text string, digits int)` so they can be tested against captured
`pdftotext` output without a PDF fixture. `pdftotext -layout` (poppler-utils) is
a runtime dependency of `nlb` and `traderepublic`; no Go library reconstructs
column layout as well.
Do not hardcode absolute column positions from a sample PDF. `pdftotext`
compresses runs of spaces, so columns shift with font and page size — derive
positions from the header line (`traderepublic`) or from the line being parsed
(`nlb`).
## Verifying
```
go build ./... && go test ./... && go vet ./... && gofmt -l .
```
For end-to-end checks, build a throwaway data root under the scratchpad rather
than touching real data:
```
money --root /tmp/.../demo import
money --root /tmp/.../demo import # must report 0 new
money --root /tmp/.../demo ls --wide
```
### Driving the TUI in tests
Prefer feeding `tea.Msg` values to `Model.Update` directly — that is how every
existing TUI test works, and it covers the keymap without a terminal.
If a real terminal is genuinely needed, note that piping into `script` does not
deliver keystrokes. Use a pty and answer the two capability queries Bubble Tea
sends on startup, or the program blocks before its first render:
- `ESC]11;?` (background colour) → reply `ESC]11;rgb:1e1e/1e1e/1e1e ESC\`
- `ESC[6n` (cursor position) → reply `ESC[1;1R`
Also delete the index first, or the import you are trying to observe will be
skipped by checksum and finish instantly.
## Conventions
Comments explain why, not what. Errors name the file and the offending row or
key so a bad statement is actionable. Per-file import failures are reported and
the run continues; only a broken data root aborts.