feat: set up modularized version of project with testing

src/timesheets/cli.py

@@ -0,0 +1,85 @@
+import argparse
+import os
+import sys
+from datetime import date
+
+from .output import print_summary, write_csv
+from .parser import aggregate_rows, detect_has_duration_column, parse_table
+from .projects import load_project_map
+from .utils import format_date
+
+
+def build_parser() -> argparse.ArgumentParser:
+    parser = argparse.ArgumentParser(
+        description="Parse a markdown timesheet table and output a CSV file."
+    )
+    parser.add_argument(
+        "input",
+        help="Path to the markdown file containing the timesheet table, or '-' to read from stdin.",
+    )
+    parser.add_argument(
+        "-o", "--output",
+        help="Path to the output CSV file. Defaults to stdout.",
+        default=None,
+    )
+    parser.add_argument(
+        "--date",
+        help="Date to use in the output (DD/MM/YY). Defaults to today.",
+        default=None,
+    )
+    parser.add_argument(
+        "--map",
+        help=(
+            "Path to a JSON file mapping project keys to Project+Task pairs. "
+            "Defaults to project_map.json in the current working directory if it exists."
+        ),
+        default=None,
+    )
+    parser.add_argument(
+        "--summary",
+        action="store_true",
+        help="Print a human-readable summary instead of writing CSV.",
+    )
+    return parser
+
+
+def main() -> None:
+    args = build_parser().parse_args()
+
+    date_str = args.date or format_date(date.today())
+
+    if args.input == "-":
+        content = sys.stdin.read()
+    else:
+        try:
+            with open(args.input, "r", encoding="utf-8") as f:
+                content = f.read()
+        except FileNotFoundError:
+            print(f"Error: file not found: {args.input}", file=sys.stderr)
+            sys.exit(1)
+
+    lines = content.splitlines()
+    rows = parse_table(lines, has_duration_col=detect_has_duration_column(lines))
+
+    if not rows:
+        print("Warning: no timesheet rows found in input.", file=sys.stderr)
+
+    aggregated = aggregate_rows(rows)
+
+    # Resolve project map: explicit --map flag, else project_map.json in cwd
+    map_path = args.map
+    if map_path is None:
+        default_map = os.path.join(os.getcwd(), "project_map.json")
+        if os.path.exists(default_map):
+            map_path = default_map
+
+    project_map = load_project_map(map_path)
+
+    if args.summary:
+        print_summary(aggregated, project_map)
+    elif args.output:
+        with open(args.output, "w", newline="", encoding="utf-8") as f:
+            write_csv(aggregated, f, date_str, project_map)
+        print(f"Written to {args.output}", file=sys.stderr)
+    else:
+        write_csv(aggregated, sys.stdout, date_str, project_map)