Idempotent Journal Posting: Bind Each Instruction to Its Original Result

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177

/** Exact journal validation and a pure committed-snapshot teaching model.
 * No database, network, sibling imports, implicit coercion, or BigInt JSON values.
 */
type RecordValue = Record<string, any>;
const COMMAND = ['schema_version','ledger_id','entity_id','journal_id','business_operation_id','currency','effective_at','source_available_at','booking_period','legs'];
const ACCOUNT = ['account_id','ledger_id','entity_id','currency','account_type','normal_side','status'];
const LEG = ['account_id','side','amount_minor'];
const CONTEXT = ['recorded_at','open_periods','allow_current_period_adjustment','adjustment_reason'];
const IDENTIFIER = /^[A-Za-z0-9][A-Za-z0-9._:-]{0,63}$/;
const AMOUNT = /^[1-9][0-9]{0,29}$/;
const TIME = /^[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}\.[0-9]{3}Z$/;
const PERIOD = /^[0-9]{4}-(0[1-9]|1[0-2])$/;
const NORMAL: Record<string,string> = {asset:'debit',expense:'debit',liability:'credit',equity:'credit',income:'credit'};
const currencies = new Set(['USD','EUR']);
const object = (x:any): x is RecordValue => x !== null && typeof x === 'object' && !Array.isArray(x) && (Object.getPrototypeOf(x) === Object.prototype || Object.getPrototypeOf(x) === null);
const exact = (x:any, fields:string[]) => object(x) && Object.keys(x).length === fields.length && fields.every(k => Object.hasOwn(x,k));
const identifier = (x:any) => typeof x === 'string' && IDENTIFIER.test(x) && !/[\r\n]/.test(x);
const period = (x:any) => typeof x === 'string' && PERIOD.test(x) && x.length === 7 && x.slice(0,4) !== '0000';
const copy = (x:any) => structuredClone(x);
// Match Python str.strip exactly; ECMAScript trim differs for NEL/control separators/BOM.
const trimText=(v:string)=>v.replace(/^[\u0009-\u000d\u001c-\u0020\u0085\u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000]+|[\u0009-\u000d\u001c-\u0020\u0085\u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000]+$/g,'');
function timestamp(x:any): boolean {
  if (typeof x !== 'string' || x.length !== 24 || !TIME.test(x) || x.slice(0,4) === '0000') return false;
  const parsed = new Date(x);
  return Number.isFinite(parsed.getTime()) && parsed.toISOString() === x;
}
function contextOk(x:any): boolean {
  return object(x) && ['recorded_at','open_periods'].every(k => Object.hasOwn(x,k)) && Object.keys(x).every(k => CONTEXT.includes(k))
    && timestamp(x.recorded_at) && Array.isArray(x.open_periods) && x.open_periods.every(period) && new Set(x.open_periods).size === x.open_periods.length
    && (!Object.hasOwn(x,'allow_current_period_adjustment') || typeof x.allow_current_period_adjustment === 'boolean')
    && (!Object.hasOwn(x,'adjustment_reason') || typeof x.adjustment_reason === 'string');
}
function accountsOk(x:any): boolean {
  if (!Array.isArray(x)) return false;
  const seen = new Set();
  for (const a of x) {
    if (!exact(a,ACCOUNT) || !['account_id','ledger_id','entity_id'].every(k => identifier(a[k])) || seen.has(a.account_id)
      || typeof a.currency !== 'string' || !currencies.has(a.currency) || typeof a.account_type !== 'string' || !Object.hasOwn(NORMAL,a.account_type)
      || a.normal_side !== NORMAL[a.account_type] || !['active','closed'].includes(a.status)) return false;
    seen.add(a.account_id);
  }
  return true;
}
function rejected(code:string, totals:any=null): any {
  return {status:'rejected',code,totals,movements:[],journal:null};
}
export function validateJournal(command:any, accounts:any, context:any): any {
  if (!accountsOk(accounts)) return rejected('INVALID_ACCOUNTS');
  if (!contextOk(context)) return rejected('INVALID_CONTEXT');
  if (!exact(command,COMMAND)) return rejected('INVALID_SCHEMA');
  if (command.schema_version !== 'd30-journal-v1') return rejected('UNSUPPORTED_SCHEMA');
  if (!['ledger_id','entity_id','journal_id','business_operation_id'].every(k => identifier(command[k]))) return rejected('INVALID_IDENTIFIER');
  if (typeof command.currency !== 'string' || !currencies.has(command.currency)) return rejected('UNSUPPORTED_CURRENCY');
  if (!timestamp(command.effective_at) || !timestamp(command.source_available_at)) return rejected('INVALID_TIMESTAMP');
  if (command.effective_at > context.recorded_at) return rejected('FUTURE_EFFECTIVE_TIME');
  if (command.source_available_at > context.recorded_at) return rejected('FUTURE_SOURCE_AVAILABILITY');
  if (!period(command.booking_period)) return rejected('INVALID_SCHEMA');
  if (!context.open_periods.includes(command.booking_period)) return rejected('PERIOD_CLOSED');
  if (command.booking_period !== command.effective_at.slice(0,7) && !(context.allow_current_period_adjustment === true && trimText(context.adjustment_reason ?? ''))) return rejected('UNAUTHORIZED_PERIOD_ADJUSTMENT');
  if (!Array.isArray(command.legs) || command.legs.length < 2 || command.legs.length > 32) return rejected('INVALID_LEGS');
  const lookup = new Map<string,RecordValue>(accounts.map((a:RecordValue) => [a.account_id,a]));
  const raw = new Map<string,bigint>();
  let debit = 0n, credit = 0n;
  for (const leg of command.legs) {
    if (!exact(leg,LEG)) return rejected('INVALID_SCHEMA');
    if (!identifier(leg.account_id)) return rejected('INVALID_IDENTIFIER');
    if (!['debit','credit'].includes(leg.side)) return rejected('INVALID_SIDE');
    if (typeof leg.amount_minor !== 'string' || !AMOUNT.test(leg.amount_minor) || /[\r\n]/.test(leg.amount_minor)) return rejected('INVALID_AMOUNT');
    const account = lookup.get(leg.account_id);
    if (!account) return rejected('UNKNOWN_ACCOUNT');
    if (account.status !== 'active') return rejected('ACCOUNT_CLOSED');
    if (account.ledger_id !== command.ledger_id || account.entity_id !== command.entity_id) return rejected('ACCOUNT_SCOPE_MISMATCH');
    if (account.currency !== command.currency) return rejected('CURRENCY_MISMATCH');
    const amount = BigInt(leg.amount_minor);
    if (leg.side === 'debit') debit += amount; else credit += amount;
    raw.set(leg.account_id,(raw.get(leg.account_id) ?? 0n) + (leg.side === 'debit' ? amount : -amount));
  }
  if (raw.size < 2) return rejected('DISTINCT_ACCOUNTS_REQUIRED');
  const totals = {debit_minor:debit.toString(),credit_minor:credit.toString(),residual_minor:(debit-credit).toString()};
  if (debit !== credit) return rejected('UNBALANCED_JOURNAL',totals);
  const movements = [...raw].map(([account_id,value]) => ({account_id,raw_delta_minor:value.toString(),normal_delta_minor:(lookup.get(account_id)!.normal_side === 'debit' ? value : -value).toString()}));
  return {status:'accepted',code:'VALID_JOURNAL',totals,movements,journal:copy(command)};
}
export function initialState(accounts:any, ledger_id='CB-GENERAL', entity_id='CB-A'): any {
  if (!accountsOk(accounts) || !identifier(ledger_id) || !identifier(entity_id)) throw new Error('Invalid trusted initial state');
  return {ledger_id,entity_id,accounts:copy(accounts),journals:[]};
}
export function postJournal(state:any, command:any, context:any): any {
  const base = copy(state);
  const fail = (code:string,totals:any=null) => ({...rejected(code,totals),state:base});
  if (!exact(state,['ledger_id','entity_id','accounts','journals']) || !identifier(state.ledger_id) || !identifier(state.entity_id) || !accountsOk(state.accounts) || !Array.isArray(state.journals)) return fail('INVALID_STATE');
  let previous:string|null = null;
  for (let i=0;i<state.journals.length;i++) {
    const j = state.journals[i];
    if (!object(j) || j.sequence !== String(i+1) || !timestamp(j.recorded_at) || j.ledger_id !== state.ledger_id || j.entity_id !== state.entity_id || (previous !== null && j.recorded_at < previous)) return fail('INVALID_STATE');
    previous = j.recorded_at;
  }
  if (object(command) && (command.ledger_id !== state.ledger_id || command.entity_id !== state.entity_id)) return fail('SCOPE_FORBIDDEN');
  const decision = validateJournal(command,state.accounts,context);
  if (decision.status === 'rejected') return {...decision,state:base};
  if (previous !== null && context.recorded_at < previous) return fail('RECORDED_TIME_REGRESSION');
  if (state.journals.some((j:RecordValue) => j.journal_id === command.journal_id)) return fail('JOURNAL_ID_CONFLICT');
  const committed = {...copy(command),sequence:String(state.journals.length+1),recorded_at:context.recorded_at,adjustment_reason:command.booking_period !== command.effective_at.slice(0,7) ? trimText(context.adjustment_reason ?? '') : ''};
  base.journals.push(copy(committed));
  return {...decision,status:'committed',code:'POSTED',journal:committed,state:base};
}

// Embedded validator keeps the downloadable reference independent of siblings.
const STATE = ['schema_version','ledger_id','entity_id','accounts','journals','operations'];
const STATE_VERSION = 'd30-idempotent-state-v1';
export function newState(accounts:any,ledger_id='CB-GENERAL',entity_id='CB-A'):any {
  return {...initialState(accounts,ledger_id,entity_id),schema_version:STATE_VERSION,operations:[]};
}
function wireError(c:any):string|null {
  if (!exact(c,COMMAND)) return 'INVALID_SCHEMA';
  if (c.schema_version !== 'd30-journal-v1') return 'UNSUPPORTED_SCHEMA';
  if (!['ledger_id','entity_id','journal_id','business_operation_id'].every(k=>identifier(c[k]))) return 'INVALID_IDENTIFIER';
  if (typeof c.currency !== 'string' || !currencies.has(c.currency)) return 'UNSUPPORTED_CURRENCY';
  if (!timestamp(c.effective_at) || !timestamp(c.source_available_at)) return 'INVALID_TIMESTAMP';
  if (!period(c.booking_period)) return 'INVALID_SCHEMA';
  if (!Array.isArray(c.legs) || c.legs.length<2 || c.legs.length>32) return 'INVALID_LEGS';
  for (const leg of c.legs) {
    if (!exact(leg,LEG)) return 'INVALID_SCHEMA';
    if (!identifier(leg.account_id)) return 'INVALID_IDENTIFIER';
    if (!['debit','credit'].includes(leg.side)) return 'INVALID_SIDE';
    if (typeof leg.amount_minor!=='string' || !AMOUNT.test(leg.amount_minor) || /[\r\n]/.test(leg.amount_minor)) return 'INVALID_AMOUNT';
  }
  return null;
}
function semanticValue(x:any):string {
  if (Array.isArray(x)) return '['+x.map(semanticValue).join(',')+']';
  if (object(x)) return '{'+Object.keys(x).sort().map(k=>JSON.stringify(k)+':'+semanticValue(x[k])).join(',')+'}';
  return JSON.stringify(x);
}
function same(a:any,b:any):boolean { return semanticValue(a)===semanticValue(b); }
function snapshotOk(s:any):boolean {
  if (!exact(s,STATE) || s.schema_version!==STATE_VERSION || !identifier(s.ledger_id) || !identifier(s.entity_id)
    || !Array.isArray(s.accounts) || !Array.isArray(s.journals) || !Array.isArray(s.operations) || s.journals.length!==s.operations.length) return false;
  const ids=new Set(), business=new Set(); let prior:string|null=null;
  for (let i=0;i<s.journals.length;i++) {
    const j=s.journals[i], op=s.operations[i];
    if (!exact(op,['command','result'])) return false;
    const c=op.command, r=op.result;
    if (wireError(c)!==null || c.ledger_id!==s.ledger_id || c.entity_id!==s.entity_id || ids.has(c.journal_id) || business.has(c.business_operation_id)
      || !exact(r,['status','code','totals','movements','journal']) || r.status!=='committed' || r.code!=='POSTED'
      || !exact(j,[...COMMAND,'sequence','recorded_at','adjustment_reason']) || !same(r.journal,j)
      || !same(Object.fromEntries(COMMAND.map(k=>[k,j[k]])),c) || j.sequence!==String(i+1) || !timestamp(j.recorded_at)
      || typeof j.adjustment_reason!=='string' || (prior!==null && j.recorded_at<prior)) return false;
    prior=j.recorded_at; ids.add(c.journal_id); business.add(c.business_operation_id);
  }
  return true;
}
/** Pure snapshot transition; the host supplies trusted authorization and atomic persistence. */
export function postIdempotent(state:any,command:any,context:any,authorized_scope:any):any {
  const base=copy(state);
  const fail=(code:string)=>({state:base,response:{status:'rejected',code,result:null}});
  if (!exact(authorized_scope,['ledger_id','entity_id']) || !identifier(authorized_scope.ledger_id) || !identifier(authorized_scope.entity_id)
    || !object(state) || state.ledger_id!==authorized_scope.ledger_id || state.entity_id!==authorized_scope.entity_id) return fail('SCOPE_FORBIDDEN');
  if (!snapshotOk(state)) return fail('INVALID_STATE');
  const error=wireError(command); if(error) return fail(error);
  if(command.ledger_id!==state.ledger_id || command.entity_id!==state.entity_id) return fail('SCOPE_FORBIDDEN');
  for(const op of state.operations) {
    if(op.command.business_operation_id===command.business_operation_id) {
      if(!same(op.command,command)) return fail('IDEMPOTENCY_CONFLICT');
      return {state:base,response:{status:'replayed',code:'REPLAYED',result:copy(op.result)}};
    }
  }
  if(state.journals.some((j:RecordValue)=>j.journal_id===command.journal_id)) return fail('JOURNAL_ID_CONFLICT');
  const decision=validateJournal(command,state.accounts,context);
  if(decision.status==='rejected') return fail(decision.code);
  if(state.journals.length && context.recorded_at<state.journals.at(-1).recorded_at) return fail('RECORDED_TIME_REGRESSION');
  const journal={...copy(command),sequence:String(state.journals.length+1),recorded_at:context.recorded_at,adjustment_reason:command.booking_period!==command.effective_at.slice(0,7)?trimText(context.adjustment_reason??''):''};
  const result={...decision,status:'committed',code:'POSTED',journal};
  base.journals.push(copy(journal)); base.operations.push({command:copy(command),result:copy(result)});
  return {state:base,response:{status:'committed',code:'POSTED',result}};
}