Make fzf prompt more legible

Do not use dcontext for precision for now. It does not seem
to be necessary.

.gitignore

@@ -1,4 +1,6 @@
+CLAUDE.md
 # ---> Python
+uv.lock
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]

pyproject.toml

@@ -7,35 +7,28 @@ name = "toldg"
 version = "0.1.0"
 description = "Tool to generate ledger files from csv"
 readme = "README.md"
-requires-python = ">=3.12,<4.0"
+requires-python = ">=3.13,<4.0"
 license = {text = "MIT"}
 authors = [
     {name = "Felix Martin", email = "mail@felixm.de"}
 ]
 dependencies = [
-    "fava (>=1.30.1,<2.0.0)",
-    "pydantic (>=2.10.6,<3.0.0)",
-    "beancount (>=3.1.0,<4.0.0)",
-    "rich (>=13.9.4,<14.0.0)",
-    "numpy (>=2.2.3,<3.0.0)"
+    "fava",
+    "pydantic",
+    "beancount",
+    "rich",
+    "numpy",
+    "ty",
+    "ruff",
 ]
 
-[tool.poetry.group.dev.dependencies]
-pre-commit = "^4.1.0"
-black = "^25.1.0"
-isort = "^6.0.1"
-pytest = "^8.3.4"
-
 [project.scripts]
 toldg = "toldg.__main__:main"
 
 [tool.setuptools]
 package-dir = {"" = "src"}
 
-[tool.black]
-line-length = 88
-target-version = ["py312"]
+[tool.ruff]
+target-version = "py313" 
+line-length = 100
 
-[tool.isort]
-profile = "black"
-line_length = 88

src/toldg/__main__.py

@@ -1,11 +1,15 @@
 import logging
 import sys
+import beancount
+import io
 
 from rich.logging import RichHandler
 
 from toldg.process import process_csv_files, process_ldg_files
 from toldg.train import train
-from toldg.utils import load_config, remove_if_exists, write_meta
+from toldg.utils import load_config, remove_if_exists
+from toldg.models import Config
+from toldg.write import render_to_file
 
 
 def init_logging():
@@ -17,16 +21,86 @@ def init_logging():
     )
 
 
+def get_new_transactions(transactions: list, csv_transactions: list) -> list:
+    key_to_transaction = {
+        (transaction.meta["source_file"], transaction.meta["source_index"]): transaction
+        for transaction in transactions
+    }
+    assert len(transactions) == len(key_to_transaction), "Transaction keys must be unique"
+
+    new_transactions = []
+    for csv_transaction in csv_transactions:
+        key = (csv_transaction.csv_file, csv_transaction.index)
+        if key in key_to_transaction:
+            existing_transaction = key_to_transaction[key]
+            if existing_transaction.meta["source_row"] != csv_transaction.row:
+                msg = f"Consistency error: CSV transaction {csv_transaction} is different to {existing_transaction}"
+                logging.error(msg)
+                raise SystemExit(1)
+        else:
+            new_transactions.append(csv_transaction)
+    logging.info(f"Got {len(new_transactions)} new and {len(transactions)} existing transactions.")
+    return new_transactions
+
+
+def update_ledger(config: Config):
+    def beancount_entry_to_string(entry) -> str:
+        buf = io.StringIO()
+        beancount.parser.printer.print_entry(entry, file=buf)
+        return buf.getvalue().strip()
+
+    def is_transaction(transaction) -> bool:
+        return isinstance(transaction, beancount.core.data.Transaction)
+
+    filename = config.output_file
+    transactions, errors, options_map = beancount.loader.load_file(filename)
+
+    if errors:
+        logging.error(f"errors in '{filename}'")
+        for err in errors:
+            logging.error(err)
+        raise SystemExit(1)
+
+    transactions.sort(key=lambda e: e.date)
+
+    # Note(felixm): Only write back transactions from the main beancount file.
+    # The issue is that `beancount.loader.load_file` does not allow for a full
+    # round trip; some of the transactions get swallowed. Therefore, treat all files
+    # that are not the main beancount file as input only files. This means
+    # these input only files can only be edited by hand, but the user can use
+    # them to set options for beancount and fava, and add other types of
+    # transactions that would otherwise disappear after the round trip. I have seen
+    # tickets on GitHub about changing this API so that everything can be
+    # written back as is, but until then, this works well for my use-case.
+    transactions = [e for e in transactions if e.meta["filename"] == str(filename.absolute())]
+
+    csv_transactions = process_csv_files(config)
+    new_transactions = get_new_transactions(transactions, csv_transactions)
+    remove_if_exists(config.output_file)
+    process_ldg_files(config)
+
+    with open(filename, "a") as f:
+        prev_item_was_transaction = False
+        for transaction in transactions:
+            if prev_item_was_transaction:
+                f.write("\n")
+            elif not prev_item_was_transaction and is_transaction(transaction):
+                f.write("\n")
+            f.write(beancount_entry_to_string(transaction))
+            f.write("\n")
+            prev_item_was_transaction = is_transaction(transaction)
+
+    render_to_file(new_transactions, config)
+    logging.info(f"Ledger file '{filename}' was written successfully.")
+
+
 def main():
     init_logging()
     config = load_config()
     if len(sys.argv) > 2 and sys.argv[2] == "train":
         train(config)
     else:
-        remove_if_exists(config.output_file)
-        write_meta(config)
-        process_ldg_files(config)
-        process_csv_files(config)
+        update_ledger(config)
 
 
 if __name__ == "__main__":

src/toldg/fzf.py

@@ -5,12 +5,12 @@ import sys
 EXECUTABLE_NAME = "fzf.exe" if sys.platform == "win32" else "fzf"
 
 
-def iterfzf(iterable, prompt="> "):
-    cmd = [EXECUTABLE_NAME, "--prompt=" + prompt]
+def iterfzf(iterable, prompt="> ", header=None, height="50%"):
+    cmd = [EXECUTABLE_NAME, "--prompt=" + prompt, "--height=" + height, "--reverse"]
+    if header:
+        cmd.append("--header=" + header)
     encoding = sys.getdefaultencoding()
-    proc = subprocess.Popen(
-        cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=None
-    )
+    proc = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=None)
     if proc.stdin is None:
         return None
     try:
@@ -24,7 +24,10 @@ def iterfzf(iterable, prompt="> "):
         return None
     if proc.stdout is None:
         return None
-    decode = lambda t: t.decode(encoding)
+
+    def decode(t):
+        return t.decode(encoding)
+
     output = [decode(ln.strip(b"\r\n\0")) for ln in iter(proc.stdout.readline, b"")]
     try:
         return output[0]

src/toldg/models.py

@@ -50,6 +50,7 @@ class Config(BaseModel):
     output_file: Path = Path("output.ldg")
     csv_configs: List[CsvConfig]
     categories: List[str]
+    model: Path = Path("transaction_classifier.pkl")
 
 
 class Mapping(BaseModel):
@@ -80,4 +81,8 @@ class Transaction(BaseModel):
     description: str
     csv_file: str
     row: str
+    index: int
     mapping: Optional[Mapping] = None
+
+    def key(self):
+        return self.csv_file + ", " + self.row

src/toldg/predict.py

@@ -1,47 +1,405 @@
-from typing import List
+import logging
+import os
+import pickle
+import re
+from collections import Counter
+from pathlib import Path
+from typing import Dict, List, Optional, Tuple
+
+import numpy as np
 
 from toldg.fzf import iterfzf
-from toldg.models import UNKNOWN_CATEGORY, Transaction
+from toldg.models import Transaction
 
 
-def get_sort_categories():
-    def sort_categories(row: str, categories: List[str]):
-        if learn is None:
-            return
-        _, _, probs = learn.predict(row)
-        cat_to_prob = dict(zip(learn.dls.vocab[1], probs.tolist()))
-        categories.sort(
-            key=lambda c: cat_to_prob[c] if c in cat_to_prob else 0.0, reverse=True
+class Tokenizer:
+    """Simple tokenizer for transaction descriptions."""
+
+    def __init__(self, min_count: int = 2, lowercase: bool = True):
+        self.min_count = min_count
+        self.lowercase = lowercase
+        self.vocab = {}  # word -> index
+        self.inverse_vocab = {}  # index -> word
+
+    def fit(self, texts: List[str]) -> None:
+        """Build vocabulary from texts."""
+        word_counts = Counter()
+
+        for text in texts:
+            tokens = self._tokenize(text)
+            word_counts.update(tokens)
+
+        # Filter words by minimum count
+        filtered_words = [word for word, count in word_counts.items() if count >= self.min_count]
+
+        # Build vocabulary
+        self.vocab = {word: idx for idx, word in enumerate(filtered_words)}
+        self.inverse_vocab = {idx: word for word, idx in self.vocab.items()}
+
+    def _tokenize(self, text: str) -> List[str]:
+        """Split text into tokens."""
+        if self.lowercase:
+            text = text.lower()
+
+        # Simple tokenization: alphanumeric sequences
+        tokens = re.findall(r"\b\w+\b", text)
+        return tokens
+
+    def transform(self, text: str) -> Dict[int, int]:
+        """Convert text to sparse vector (word index -> count)."""
+        tokens = self._tokenize(text)
+        counts = Counter()
+
+        for token in tokens:
+            if token in self.vocab:
+                counts[self.vocab[token]] += 1
+
+        return dict(counts)
+
+    def vocab_size(self) -> int:
+        """Return vocabulary size."""
+        return len(self.vocab)
+
+
+class LogisticRegression:
+    """Multi-class logistic regression classifier."""
+
+    def __init__(
+        self,
+        input_dim: int,
+        output_dim: int,
+        learning_rate: float = 0.01,
+        reg_lambda: float = 0.01,
+        max_iterations: int = 1000,
+    ):
+        self.input_dim = input_dim
+        self.output_dim = output_dim
+        self.learning_rate = learning_rate
+        self.reg_lambda = reg_lambda
+        self.max_iterations = max_iterations
+
+        # Initialize weights and bias
+        # weights shape: (output_dim, input_dim)
+        self.weights = np.random.randn(output_dim, input_dim) * 0.01
+        self.bias = np.zeros((output_dim, 1))
+
+    def softmax(self, z: np.ndarray) -> np.ndarray:
+        """Compute softmax function."""
+        # Subtract max for numerical stability
+        exp_z = np.exp(z - np.max(z, axis=0, keepdims=True))
+        return exp_z / np.sum(exp_z, axis=0, keepdims=True)
+
+    def forward(self, x: np.ndarray) -> np.ndarray:
+        """Forward pass: compute probabilities."""
+        # x shape: (input_dim, batch_size)
+        # output shape: (output_dim, batch_size)
+        z = np.dot(self.weights, x) + self.bias
+        return self.softmax(z)
+
+    def compute_loss(self, y_pred: np.ndarray, y_true: np.ndarray) -> float:
+        """Compute cross-entropy loss with L2 regularization."""
+        # y_pred shape: (output_dim, batch_size)
+        # y_true shape: (output_dim, batch_size) - one-hot encoded
+        m = y_true.shape[1]
+
+        # Cross-entropy loss
+        ce_loss = -np.sum(y_true * np.log(y_pred + 1e-8)) / m
+
+        # L2 regularization
+        reg_loss = (self.reg_lambda / (2 * m)) * np.sum(np.square(self.weights))
+
+        return ce_loss + reg_loss
+
+    def backward(
+        self, x: np.ndarray, y_pred: np.ndarray, y_true: np.ndarray
+    ) -> Tuple[np.ndarray, np.ndarray]:
+        """Compute gradients for backpropagation."""
+        # x shape: (input_dim, batch_size)
+        # y_pred shape: (output_dim, batch_size)
+        # y_true shape: (output_dim, batch_size) - one-hot encoded
+        m = y_true.shape[1]
+
+        # Gradient of loss with respect to scores (dL/dz)
+        dz = y_pred - y_true
+
+        # Gradient of loss with respect to weights (dL/dW)
+        dw = (1 / m) * np.dot(dz, x.T) + (self.reg_lambda / m) * self.weights
+
+        # Gradient of loss with respect to bias (dL/db)
+        db = (1 / m) * np.sum(dz, axis=1, keepdims=True)
+
+        return dw, db
+
+    def train(
+        self, x_batch: List[Dict[int, int]], y_batch: List[int], verbose: bool = True
+    ) -> List[float]:
+        """Train model on batched data."""
+        # Convert sparse vectors to dense matrix
+        batch_size = len(x_batch)
+        x_dense = np.zeros((self.input_dim, batch_size))
+
+        for i, x_sparse in enumerate(x_batch):
+            for idx, val in x_sparse.items():
+                x_dense[idx, i] = val
+
+        # Convert labels to one-hot encoding
+        y_one_hot = np.zeros((self.output_dim, batch_size))
+        for i, y in enumerate(y_batch):
+            y_one_hot[y, i] = 1
+
+        losses = []
+
+        for iteration in range(self.max_iterations):
+            # Forward pass
+            y_pred = self.forward(x_dense)
+
+            # Compute loss
+            loss = self.compute_loss(y_pred, y_one_hot)
+            losses.append(loss)
+
+            if verbose and iteration % 100 == 0:
+                print(f"Iteration {iteration}: loss = {loss:.4f}")
+
+            # Check convergence
+            if iteration > 0 and abs(losses[-1] - losses[-2]) < 1e-5:
+                if verbose:
+                    print(f"Converged at iteration {iteration}")
+                break
+
+            # Backward pass
+            dw, db = self.backward(x_dense, y_pred, y_one_hot)
+
+            # Update parameters
+            self.weights -= self.learning_rate * dw
+            self.bias -= self.learning_rate * db
+
+        return losses
+
+    def predict_proba(self, x_sparse: Dict[int, int]) -> np.ndarray:
+        """Predict class probabilities for a single sparse vector."""
+        # Convert sparse vector to dense vector
+        x_dense = np.zeros((self.input_dim, 1))
+        for idx, val in x_sparse.items():
+            x_dense[idx, 0] = val
+
+        # Forward pass
+        return self.forward(x_dense).flatten()
+
+    def predict(self, x_sparse: Dict[int, int]) -> int:
+        """Predict class for a single sparse vector."""
+        probs = self.predict_proba(x_sparse)
+        return np.argmax(probs)
+
+
+class TransactionClassifier:
+    """Transaction classifier using Bag of Words and Logistic Regression."""
+
+    def __init__(self, model_path: Optional[Path] = None):
+        self.tokenizer = None
+        self.model = None
+        self.categories = []
+        self.category_to_idx = {}
+        self.idx_to_category = {}
+
+        if model_path and os.path.exists(model_path):
+            self.load(model_path)
+
+    def fit(
+        self,
+        transactions: List[Transaction],
+        categories: List[str],
+        verbose: bool = True,
+    ) -> None:
+        """Train classifier on transactions."""
+        # Extract texts and labels
+        texts = [t.row for t in transactions]
+        labels = [t.account2 for t in transactions]
+
+        # Build category mapping
+        self.categories = sorted(set(categories))
+        self.category_to_idx = {cat: idx for idx, cat in enumerate(self.categories)}
+        self.idx_to_category = {idx: cat for cat, idx in self.category_to_idx.items()}
+
+        # Map labels to indices
+        label_indices = [self.category_to_idx.get(label, 0) for label in labels]
+
+        # Initialize and fit tokenizer
+        self.tokenizer = Tokenizer(min_count=2)
+        self.tokenizer.fit(texts)
+
+        if verbose:
+            print(f"Vocabulary size: {self.tokenizer.vocab_size()}")
+
+        # Transform texts to feature vectors
+        x_vectors = [self.tokenizer.transform(text) for text in texts]
+
+        # Initialize and train model
+        self.model = LogisticRegression(
+            input_dim=self.tokenizer.vocab_size(),
+            output_dim=len(self.categories),
+            learning_rate=0.05,
+            reg_lambda=0.01,
+            max_iterations=3000,
         )
 
-    learn = None
-    try:
-        from fastai.text.all import load_learner
+        self.model.train(x_vectors, label_indices, verbose=verbose)
 
-        learn = load_learner("export.pkl")
-    except ModuleNotFoundError:
-        user_input = input("No fastai module. Type yes to continue anyway.")
-        if user_input.strip().lower() != "yes":
-            raise Exception("fastai module missing")
+    def predict(self, text: str) -> Tuple[str, float, List[float]]:
+        """
+        Predict category for a transaction text.
+
+        Returns:
+            tuple: (predicted_category, confidence, all_probabilities)
+        """
+        if not self.model or not self.tokenizer:
+            raise ValueError("Model not trained yet")
+
+        # Transform text to feature vector
+        x_vector = self.tokenizer.transform(text)
+
+        # Predict probabilities
+        probs = self.model.predict_proba(x_vector)
+
+        # Get predicted class
+        pred_idx = np.argmax(probs)
+        pred_category = self.idx_to_category[pred_idx]
+        confidence = probs[pred_idx]
+
+        return pred_category, confidence, probs
+
+    def sort_categories(self, text: str, categories: List[str]) -> None:
+        """Sort categories by prediction probability for given text."""
+        if not self.model or not self.tokenizer:
+            return
+
+        # Transform text to feature vector
+        x_vector = self.tokenizer.transform(text)
+
+        # Predict probabilities
+        probs = self.model.predict_proba(x_vector)
+
+        # Create mapping from category to probability
+        cat_to_prob = {}
+        for idx, prob in enumerate(probs):
+            if idx in self.idx_to_category:
+                cat = self.idx_to_category[idx]
+                cat_to_prob[cat] = prob
+
+        # Sort categories by probability
+        categories.sort(key=lambda c: cat_to_prob.get(c, 0.0), reverse=True)
+
+    def save(self, path: Path) -> None:
+        """Save model to file."""
+        if not self.model or not self.tokenizer:
+            raise ValueError("Model not trained yet")
+
+        model_data = {
+            "tokenizer_vocab": self.tokenizer.vocab,
+            "tokenizer_inverse_vocab": self.tokenizer.inverse_vocab,
+            "tokenizer_min_count": self.tokenizer.min_count,
+            "tokenizer_lowercase": self.tokenizer.lowercase,
+            "model_weights": self.model.weights,
+            "model_bias": self.model.bias,
+            "categories": self.categories,
+            "category_to_idx": self.category_to_idx,
+            "idx_to_category": self.idx_to_category,
+        }
+
+        with open(path, "wb") as f:
+            pickle.dump(model_data, f)
+
+    def load(self, path: Path) -> None:
+        """Load model from file."""
+        with open(path, "rb") as f:
+            model_data = pickle.load(f)
+
+        # Restore tokenizer
+        self.tokenizer = Tokenizer(
+            min_count=model_data["tokenizer_min_count"],
+            lowercase=model_data["tokenizer_lowercase"],
+        )
+        self.tokenizer.vocab = model_data["tokenizer_vocab"]
+        self.tokenizer.inverse_vocab = model_data["tokenizer_inverse_vocab"]
+
+        # Restore categories
+        self.categories = model_data["categories"]
+        self.category_to_idx = model_data["category_to_idx"]
+        self.idx_to_category = model_data["idx_to_category"]
+
+        # Restore model
+        input_dim = len(self.tokenizer.vocab)
+        output_dim = len(self.categories)
+        self.model = LogisticRegression(input_dim, output_dim)
+        self.model.weights = model_data["model_weights"]
+        self.model.bias = model_data["model_bias"]
+
+
+def train_classifier(
+    transactions: List[Transaction],
+    categories: List[str],
+    output_path: Path = Path("transaction_classifier.pkl"),
+):
+    """Train transaction classifier and save to file."""
+    global _classifier
+
+    # Filter transactions with account2
+    valid_transactions = [t for t in transactions if t.account2 in categories]
+
+    if len(valid_transactions) < 10:
+        logging.warning("Not enough transactions for training. Need at least 10.")
+        return
+
+    logging.info(f"Training classifier on {len(valid_transactions)} transactions")
+
+    # Initialize and train classifier
+    _classifier = TransactionClassifier()
+    _classifier.fit(valid_transactions, categories, verbose=True)
+
+    # Save classifier
+    _classifier.save(output_path)
+    logging.info(f"Classifier saved to {output_path}")
+
+
+def get_sort_categories(model_path: Path):
+    """Get function to sort categories by prediction probability."""
+    _classifier = None
+
+    def sort_categories(row: str, categories: List[str]):
+        if _classifier is None:
+            return
+        _classifier.sort_categories(row, categories)
+
+    try:
+        model_path = Path("transaction_classifier.pkl")
+        _classifier = TransactionClassifier(model_path)
+        if _classifier.model is None:
+            logging.warning("No trained model found. Categories will not be sorted.")
+    except Exception as e:
+        logging.warning(f"Error loading classifier: {e}")
+        logging.warning("Categories will not be sorted.")
 
     return sort_categories
 
 
-def add_account2(transactions: List[Transaction], categories: List[str]):
-    unmapped_transactions = list(filter(lambda t: t.mapping == None, transactions))
+def add_account2(model_path: Path, transactions: List[Transaction], categories: List[str]):
+    """Add account2 to unmapped transactions."""
+    unmapped_transactions = list(filter(lambda t: t.mapping is None, transactions))
     if len(unmapped_transactions) == 0:
         return
-    sort_categories = get_sort_categories()
+
+    sort_categories = get_sort_categories(model_path)
     for t in unmapped_transactions:
         sort_categories(t.row, categories)
         add_account2_interactive(t, categories)
 
 
 def add_account2_interactive(transaction: Transaction, categories: List[str]):
+    """Interactively add account2 to a transaction."""
     t = transaction
     account2 = None
-    prompt = f"{t.account1} {t.date} {t.description} {t.debit} > "
+    header = f"{t.account1} | {t.date} | {t.description} | {t.debit}"
+    logging.warning(f"No mapping for '{t}'.")
     while account2 is None:
-        account2 = iterfzf(categories, prompt=prompt)
+        account2 = iterfzf(categories, header=header)
     transaction.account2 = account2
     print(f"Assigned category '{account2}'.")

src/toldg/process.py

@@ -1,9 +1,9 @@
 import csv
 import datetime
 import logging
+import os
 import re
 import sys
-from typing import Any, Dict, List
 
 import toldg.models
 import toldg.predict
@@ -13,13 +13,13 @@ from toldg.models import Config, CsvConfig, Mapping, Transaction
 
 
 def process_ldg_files(config: Config):
-    for ldg_file in toldg.utils.get_ldg_files(config.input_directory):
-        with open(ldg_file, "r") as f_in:
-            with open(config.output_file, "a") as f_out:
-                f_out.write(f_in.read())
+    with open(config.output_file, "a") as f_out:
+        for ldg_file in toldg.utils.get_ldg_files(config.input_directory):
+            ldg_rel = os.path.relpath(ldg_file, os.path.dirname(config.output_file))
+            f_out.write(f'include "{ldg_rel}"\n')
 
 
-def get_csv_config(csv_file: str, csv_configs: List[CsvConfig]) -> CsvConfig:
+def get_csv_config(csv_file: str, csv_configs: list[CsvConfig]) -> CsvConfig:
     cs = [c for c in csv_configs if re.match(c.file_match_regex, csv_file)]
     if not cs:
         logging.critical(f"No CSV config for {csv_file}.")
@@ -30,7 +30,7 @@ def get_csv_config(csv_file: str, csv_configs: List[CsvConfig]) -> CsvConfig:
     return cs[0]
 
 
-def get_transactions(csv_file: str, config: CsvConfig) -> List[Transaction]:
+def get_transactions(csv_file: str, config: CsvConfig) -> list[Transaction]:
     def date_to_date(date: str) -> str:
         d = datetime.datetime.strptime(date, config.input_date_format)
         return d.strftime(config.output_date_format)
@@ -38,7 +38,7 @@ def get_transactions(csv_file: str, config: CsvConfig) -> List[Transaction]:
     def flip_sign(amount: str) -> str:
         return amount[1:] if amount.startswith("-") else "-" + amount
 
-    def row_to_transaction(row, fields):
+    def row_to_transaction(idx, row, fields):
         """The user can configure the mapping of CSV fields to the three
         required fields date, amount and description via the CsvConfig."""
         t = {field: row[index] for index, field in fields}
@@ -52,7 +52,8 @@ def get_transactions(csv_file: str, config: CsvConfig) -> List[Transaction]:
             account2=toldg.models.UNKNOWN_CATEGORY,
             description=t["description"],
             csv_file=csv_file,
-            row=csv_file + ", " + ", ".join(row),
+            row=", ".join(row),
+            index=idx,
         )
 
     fields = [(i, f) for i, f in enumerate(config.fields) if f]
@@ -60,29 +61,31 @@ def get_transactions(csv_file: str, config: CsvConfig) -> List[Transaction]:
         reader = csv.reader(f, delimiter=config.delimiter, quotechar=config.quotechar)
         for _ in range(config.skip):
             next(reader)
-        transactions = [row_to_transaction(row, fields) for row in reader if row]
+        rows = [row for row in reader if row]
+    transactions = [row_to_transaction(i, row, fields) for i, row in enumerate(reversed(rows))]
     return transactions
 
 
-def apply_mappings(transactions: List[Transaction], mappings: Dict[str, Mapping]):
+def apply_mappings(transactions: list[Transaction], mappings: dict[str, Mapping]):
     """Apply mappings to transactions."""
+    unmapped_count = 0
     for t in transactions:
-        if t.row in mappings:
-            mapping = mappings[t.row]
+        if t.key() in mappings:
+            mapping = mappings[t.key()]
             assert isinstance(mapping, Mapping)
-            assert (
-                mapping.count > 0
-            ), f"{mapping} used by {t} but count is not greater than '0'."
+            assert mapping.count > 0, f"{mapping} used by {t} but count is not greater than '0'."
             mapping.count -= 1
             t.mapping = mapping
         else:
-            logging.warning(f"No mapping for '{t}'.")
+            unmapped_count += 1
+    if unmapped_count > 0:
+        logging.info(f"{unmapped_count} transactions without mappings.")
 
     for mapping in mappings.values():
         assert mapping.count == 0, f"{mapping} was not used as often as expected!"
 
 
-def process_csv_files(config: Config) -> List[Transaction]:
+def process_csv_files(config: Config) -> list[Transaction]:
     csv_files = toldg.utils.get_csv_files(config.input_directory)
     transactions = []
     for csv_file in csv_files:
@@ -92,7 +95,6 @@ def process_csv_files(config: Config) -> List[Transaction]:
 
     mappings = toldg.utils.read_mappings(config.mappings_file)
     apply_mappings(transactions, mappings)
-    toldg.predict.add_account2(transactions, config.categories)
+    toldg.predict.add_account2(config.model, transactions, config.categories)
     toldg.utils.write_mappings(transactions, config.mappings_file)
-    toldg.write.render_to_file(transactions, config)
     return transactions

src/toldg/train.py

@@ -1,9 +1,13 @@
-from toldg.models import Config, CsvConfig, Mapping, Transaction
+import logging
+
+from toldg.models import Config
+from toldg.predict import train_classifier
 from toldg.process import process_csv_files
 
 
 def train(config: Config):
-    print("[train] start")
+    """Train a transaction classifier from csv files."""
+    # Process transactions to get training data
     transactions = process_csv_files(config)
-    for t in transactions:
-        pass
+    train_classifier(transactions, config.categories, config.model)
+    logging.info("Training completed")

src/toldg/utils.py

@@ -3,7 +3,7 @@ import logging
 import os
 import sys
 from pathlib import Path
-from typing import Any, Dict, List, Optional
+from typing import Dict, List
 
 from pydantic import ValidationError
 
@@ -57,29 +57,19 @@ def category_to_bean(c: str) -> str:
     return ":".join(new_sections)
 
 
-def write_meta(config: Config):
-    with open(config.output_file, "a") as f:
-        for category in config.categories:
-            f.write(f"2017-01-01 open {category_to_bean(category)}\n")
-        f.write("\n")
-        f.write('option "operating_currency" "USD"\n\n')
-
-
 def write_mappings(transactions: List[Transaction], mappings_file: Path):
     """Write transactions to the mappings file."""
 
     mappings = read_mappings(mappings_file)
     for t in transactions:
-        if t.row in mappings:
+        if t.key() in mappings:
             pass
         else:
             mapping = Mapping(
-                **{
-                    "account2": t.account2.strip(),
-                    "narration": t.description,
-                }
+                account2=t.account2.strip(),
+                narration=t.description,
             )
-            mappings[t.row] = mapping
+            mappings[t.key()] = mapping
 
     mappings = {k: v.model_dump(exclude_none=True) for k, v in mappings.items()}
     with open(mappings_file, "w") as f:

src/toldg/write.py

@@ -1,4 +1,3 @@
-from pathlib import Path
 from typing import List
 
 from toldg.models import Config, Transaction
@@ -6,14 +5,16 @@ from toldg.utils import category_to_bean
 
 BEANCOUNT_TRANSACTION_TEMPLATE = """
 {t.date} * {description}{tags}
-    {t.account2:<40}  {t.debit:<6} {t.currency}
-    {t.account1:<40}  {t.credit:<6} {t.currency}
+    source_file: "{t.csv_file}"
+    source_index: {t.index}
+    source_row: "{t.row}"
+    {account2:<40}  {t.debit:<6} {t.currency}
+    {account1:<40}  {t.credit:<6} {t.currency}
 """
 
 
 def format(t):
     t.date = t.date.replace("/", "-")
-
     tags = ""
     description = None
     if t.mapping:
@@ -40,13 +41,15 @@ def format(t):
     if not t.credit.startswith("-"):
         t.credit = " " + t.credit
 
-    t.account1 = category_to_bean(t.account1)
-    t.account2 = category_to_bean(t.account2)
     if t.currency == "EUR":
         t.debit = t.debit.replace(".", "|").replace(",", ".").replace("|", ",")
         t.credit = t.credit.replace(".", "|").replace(",", ".").replace("|", ",")
     return BEANCOUNT_TRANSACTION_TEMPLATE.format(
-        t=t, description=description, tags=tags
+        t=t,
+        description=description,
+        tags=tags,
+        account1=category_to_bean(t.account1),
+        account2=category_to_bean(t.account2),
     )