usawa

commit 88df6833c0e674227227ac5fa92104eb5a992f15
parent 816414ef26259d09c04254235bb6199c6ecdac36
Author: lash <dev@holbrook.no>
Date:   Mon, 23 Mar 2026 21:12:49 -0600

Start balancer logic

Diffstat:
A
dummy/tests/balance.py
 | 
36
++++++++++++++++++++++++++++++++++++
M
dummy/tests/entry.py
 | 
13
+++++++++++++
A
dummy/usawa/balance.py
 | 
82
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M
dummy/usawa/entry.py
 | 
12
++++++++++++
M
dummy/usawa/error.py
 | 
4
++++

5 files changed, 147 insertions(+), 0 deletions(-)
diff --git a/dummy/tests/balance.py b/dummy/tests/balance.py
@@ -0,0 +1,36 @@
+import logging
+import unittest
+import datetime
+import os
+
+from usawa import EntryPart, Entry, UnitIndex
+from usawa.balance import Balancer
+
+logging.basicConfig(level=logging.DEBUG)
+logg = logging.getLogger()
+
+testdir = os.path.realpath(os.path.dirname(__file__))
+
+class TestBalancer(unittest.TestCase):
+
+    def setUp(self):
+        self.parent = bytes.fromhex('0cf9180a764aba863a67b6d72f0918bc131c6772642cb2dce5a34f0a702f9470ddc2bf125c12198b1995c233c34b4afd346c54a2334c350a948a51b6e8b4e6b6')
+        self.ref = '1bda7dfa-b8fd-400d-8b42-1d2861ad7f70'
+        self.uidx = UnitIndex('FOO')
+        self.uidx.add('BAR', 3)
+        self.description = "foo bar baz"
+        self.dtreg = datetime.datetime.now()
+
+
+    def test_balancer_basic(self):
+        dst = EntryPart('FOO', 'asset', 'foo', 1337)
+        src = EntryPart('FOO', 'income', 'baz', 1337, debit=True)
+        entry = Entry(42, datetime.datetime.strptime('2025-11-11', '%Y-%m-%d'), parent=self.parent, ref=self.ref, description=self.description, tx_datereg=self.dtreg)
+        entry.add_part(src)
+        entry.add_part(dst)
+        o = Balancer(self.uidx, entry, base='FOO')
+        self.assertTrue(o.balanced())
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/dummy/tests/entry.py b/dummy/tests/entry.py
@@ -126,5 +126,18 @@ class TestEntry(unittest.TestCase):
         entry = Entry.from_tree(tree, self.uidx)
 
 
+    def test_entry_mux(self):
+        dst_one = EntryPart('FOO', 'asset', 'foo', 1337)
+        dst_two = EntryPart('FOO', 'asset', 'bar', 42)
+        src = EntryPart('FOO', 'income', 'baz', 1337+42, debit=True)
+        o = Entry(42, datetime.datetime.strptime('2025-11-11', '%Y-%m-%d'), parent=self.parent, ref=self.ref, description=self.description, tx_datereg=self.dtreg)
+        o.add_part(src, debit=True)
+        o.add_part(dst_one)
+        o.add_part(dst_two)
+        wallet = DemoWallet()
+        data = o.wrap(wallet=wallet)
+        print(list(o))
+
+
 if __name__ == '__main__':
     unittest.main()
diff --git a/dummy/usawa/balance.py b/dummy/usawa/balance.py
@@ -0,0 +1,82 @@
+import logging
+
+logg = logging.getLogger('usawa.balancer')
+
+
+class Balancer:
+
+    def __init__(self, uidx, entry, base=None):
+        self.r = 0
+        self.uidx = uidx
+        self.max_precision = 0
+        self.ex = {}
+        self.base = base
+        self.scan(entry)
+        self.process(entry)
+
+
+    def scan(self, entry):
+        base = None
+        for part in entry:
+            precision = self.uidx.get(part.unit)
+            if precision > self.max_precision:
+                self.max_precision = precision
+            self.ex[part.unit] = 1000000000
+            if base == None:
+                base = part.unit
+                continue
+            if base != part.unit:
+                if self.base == None:
+                    logg.warning('base is not set with entry with different units')
+        logg.debug('have max precision {}'.format(self.max_precision))
+        self.base = base
+
+
+    def set_rate(self, unit, rate):
+        if unit == self.base:
+            raise ValueError('base rate against itself')
+        self.ex[unit] = rate
+
+
+    def process(self, entry):
+        for part in entry:
+            precision = self.uidx.get(part.unit)
+            mod = 10 ** (self.max_precision - precision)
+            amount = part.amount * mod
+            ex = self.ex[part.unit] / 1000000000
+            amount *= ex
+            fn = getattr(self, 'handle_' + part.typ)
+            fn(amount, part.isdebit)
+            logg.debug('after {} {} (ex {}) = {}'.format(part.unit, amount, ex, self.r))
+
+
+    def balanced(self):
+        return self.r == 0
+
+
+    def handle_income(self, amount, issrc=False):
+        if issrc:
+            self.r += amount
+        else:
+            self.r -= amount
+
+
+    def handle_expense(self, amount, issrc=False):
+        if issrc:
+            self.r -= amount
+        else:
+            self.r += amount
+
+    
+    def handle_asset(self, amount, issrc=False):
+        if issrc:
+            self.r += amount
+        else:
+            self.r -= amount
+
+
+    def handle_liability(self, amount, issrc=False):
+        if issrc:
+            self.r -= amount
+        else:
+            self.r += amount
diff --git a/dummy/usawa/entry.py b/dummy/usawa/entry.py
@@ -204,6 +204,7 @@ class Entry(UsawaElement):
         self.credit = []
         self.lookup = None
         self.lookup_algo = None
+        self.parts = []
 
 
     @staticmethod
@@ -658,5 +659,16 @@ class Entry(UsawaElement):
         return b.encode('utf-8')
 
 
+    def __iter__(self):
+        self.parts = self.debit + self.credit
+        return self
+
+
+    def __next__(self):
+        if len(self.parts) == 0:
+            raise StopIteration()
+        return self.parts.pop(0)
+
+
     def __str__(self):
         return 'entry serial {} date {} parent {}'.format(self.serial, self.dt, self.parent.hex())
diff --git a/dummy/usawa/error.py b/dummy/usawa/error.py
@@ -16,3 +16,7 @@ class SocketError(Exception):
 
 class AccountError(Exception):
     pass
+
+
+class BalanceError(Exception):
+    pass