Invoice Chasing Agent

"""
Invoice Chasing Agent
- Reads open invoices from a CSV export.
- Sorts each overdue invoice onto a reminder ladder by days overdue.
- Drafts the right reminder; a sent-log prevents double-sends.
- Every message is a DRAFT for approval. Nothing sends itself.
"""
import csv
import json
from datetime import date, datetime
from pathlib import Path

from crewai import Agent, Task, Crew, Process
from crewai_tools import tool


INVOICES = Path("invoices.csv")
SENT_LOG = Path("state/reminders_sent.jsonl")   # {invoice_id, rung, date}
DO_NOT_CHASE = ["ACME-HOLDINGS"]  # clients you handle personally

# The ladder: (days overdue, rung name, tone instruction)
LADDER = [
    (7,  "nudge", "Warm and brief. Assume they simply missed it. "
                  "Re-attach nothing; link the invoice."),
    (21, "firm",  "Polite but direct. State the amount, the original due "
                  "date, and ask for a payment date."),
    (45, "final", "Professional final notice. State that the account is "
                  "on hold and describe the next step EXACTLY as written "
                  "in [your invoice terms]. No improvised threats."),
]


# ---------- Stub tools (replace with real implementations) ----------

@tool("read_overdue_invoices")
def read_overdue_invoices() -> str:
    """Return unpaid invoices with days_overdue computed."""
    today = date.today()
    rows = []
    with open(INVOICES) as f:
        for row in csv.DictReader(f):
            if row["status"].lower() != "unpaid":
                continue
            due = datetime.strptime(row["due_date"], "%Y-%m-%d").date()
            row["days_overdue"] = (today - due).days
            rows.append(row)
    return json.dumps([r for r in rows if r["days_overdue"] > 0])


@tool("check_already_sent")
def check_already_sent(invoice_id: str, rung: str) -> str:
    """Return 'yes' if this rung was already sent for this invoice.
    This is the idempotency guard: one rung, one send, ever."""
    if not SENT_LOG.exists():
        return "no"
    for line in SENT_LOG.read_text().splitlines():
        rec = json.loads(line)
        if rec["invoice_id"] == invoice_id and rec["rung"] == rung:
            return "yes"
    return "no"


@tool("draft_reminder")
def draft_reminder(invoice_id: str, client_email: str,
                   rung: str, message: str) -> str:
    """Queue a reminder draft for approval and record it in the sent-log.
    Real implementation: create a Gmail draft, still never auto-send."""
    print(f"\n[DRAFT: {rung}] to {client_email} re {invoice_id}")
    print(message)
    print("[END DRAFT - awaiting your approval]\n")
    SENT_LOG.parent.mkdir(parents=True, exist_ok=True)
    with open(SENT_LOG, "a") as f:
        f.write(json.dumps({"invoice_id": invoice_id, "rung": rung,
                            "date": str(date.today())}) + "\n")
    return "drafted"


# ---------- Agent ----------

collections_clerk = Agent(
    role="Accounts Receivable Clerk",
    goal=(
        "Draft the correct reminder for each overdue invoice, exactly "
        "once per ladder rung, in the tone the rung specifies."
    ),
    backstory=(
        "You work for [business name]. You are unfailingly polite and "
        "never embarrassed to ask for money that is owed. You never "
        "invent late fees, discounts, or consequences: if it is not in "
        "the invoice terms, it does not go in the email."
    ),
    tools=[read_overdue_invoices, check_already_sent, draft_reminder],
    verbose=True,
)

chase_task = Task(
    description=(
        "Read overdue invoices. For each one:\n"
        f"1. Skip clients in this list entirely: {DO_NOT_CHASE}.\n"
        "2. Pick the highest ladder rung whose day threshold is met "
        "(7=nudge, 21=firm, 45=final).\n"
        "3. Call check_already_sent for that rung. If 'yes', skip.\n"
        "4. Draft the reminder in the rung's tone. Include the invoice "
        "ID, amount, original due date, and payment link "
        "[your payment link or 'see invoice'].\n"
        "Sign every message as [your name], [business name].\n\n"
        "Output: JSON list of {invoice_id, rung, action_taken}."
    ),
    agent=collections_clerk,
    expected_output="JSON list of chase actions.",
)

crew = Crew(agents=[collections_clerk], tasks=[chase_task],
            process=Process.sequential, verbose=True)

if __name__ == "__main__":
    print(crew.kickoff())