Invoice generator script for OpenClaw skill tutorial

generate_invoice.py

"""Generate a PDF invoice from client details and line items."""
import argparse, json, os
from datetime import date

from reportlab.lib.pagesizes import letter
from reportlab.lib.colors import HexColor
from reportlab.lib.units import inch
from reportlab.platypus import (
    SimpleDocTemplate, Table, TableStyle,
    Spacer, Paragraph, HRFlowable,
)
from reportlab.lib.styles import ParagraphStyle

DARK = HexColor("#2C3E50")
GRAY = HexColor("#7F8C8D")
WHITE = HexColor("#FFFFFF")
LIGHT_BG = HexColor("#F8F9FA")


def build_invoice(client, items, output_path):
    doc = SimpleDocTemplate(
        output_path, pagesize=letter,
        leftMargin=0.75 * inch, rightMargin=0.75 * inch,
        topMargin=0.6 * inch, bottomMargin=0.6 * inch,
    )

    s = {
        "title": ParagraphStyle("t", fontSize=28,
            fontName="Helvetica-Bold", textColor=DARK, leading=34),
        "label": ParagraphStyle("l", fontSize=10,
            fontName="Helvetica-Bold", textColor=GRAY, leading=14),
        "value": ParagraphStyle("v", fontSize=10,
            fontName="Helvetica", textColor=DARK, leading=14),
        "header": ParagraphStyle("h", fontSize=9,
            fontName="Helvetica-Bold", textColor=WHITE, leading=12),
        "cell": ParagraphStyle("c", fontSize=10,
            fontName="Helvetica", textColor=DARK, leading=14),
        "bold": ParagraphStyle("b", fontSize=10,
            fontName="Helvetica-Bold", textColor=DARK, leading=14),
        "total": ParagraphStyle("tot", fontSize=12,
            fontName="Helvetica-Bold", textColor=DARK, leading=16),
    }

    elements = [Paragraph("INVOICE", s["title"]), Spacer(1, 20)]

    # Invoice metadata
    today = date.today()
    inv_num = f"INV-{today:%Y%m}-001"
    meta_data = [
        [Paragraph("<b>Invoice Number:</b>", s["label"]),
         Paragraph(inv_num, s["value"])],
        [Paragraph("<b>Date:</b>", s["label"]),
         Paragraph(f"{today:%B %d, %Y}", s["value"])],
        [Paragraph("<b>Due Date:</b>", s["label"]),
         Paragraph("Upon Receipt", s["value"])],
    ]
    meta_table = Table(meta_data, colWidths=[120, 300])
    meta_table.setStyle(TableStyle([
        ("VALIGN", (0, 0), (-1, -1), "MIDDLE"),
        ("BOTTOMPADDING", (0, 0), (-1, -1), 4),
        ("TOPPADDING", (0, 0), (-1, -1), 4),
    ]))
    elements.append(meta_table)
    elements.append(Spacer(1, 25))

    # From / Bill To
    section_header = ParagraphStyle("sh", fontSize=9,
        fontName="Helvetica-Bold", textColor=GRAY, leading=12)
    from_to_data = [
        [Paragraph("FROM", section_header),
         Paragraph("BILL TO", section_header)],
        [Paragraph(
            "<b>Jane Smith</b><br/>"
            "Smith Consulting LLC<br/>"
            "123 Main St, Suite 400<br/>"
            "San Francisco, CA 94105<br/>"
            "jane@smithconsulting.com", s["value"]),
         Paragraph(
            f"<b>{client}</b><br/>"
            "billing@acmecorp.com", s["value"])],
    ]
    from_to_table = Table(from_to_data,
        colWidths=[doc.width / 2.0] * 2)
    from_to_table.setStyle(TableStyle([
        ("VALIGN", (0, 0), (-1, -1), "TOP"),
        ("TOPPADDING", (0, 0), (-1, -1), 4),
        ("BOTTOMPADDING", (0, 0), (-1, -1), 4),
    ]))
    elements.append(from_to_table)
    elements.append(Spacer(1, 30))

    # Line items table
    col_w = [doc.width * w for w in (0.50, 0.15, 0.15, 0.20)]
    rows = [[Paragraph(h, s["header"])
             for h in ("DESCRIPTION", "HOURS", "RATE", "AMOUNT")]]

    subtotal = 0.0
    for it in items:
        amt = it["hours"] * it["rate"]
        subtotal += amt
        rows.append([
            Paragraph(it["description"], s["cell"]),
            Paragraph(str(it["hours"]), s["cell"]),
            Paragraph(f"${it['rate']:.2f}", s["cell"]),
            Paragraph(f"${amt:.2f}", s["cell"]),
        ])

    tbl = Table(rows, colWidths=col_w)
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0, 0), (-1, 0), DARK),
        ("TEXTCOLOR", (0, 0), (-1, 0), WHITE),
        ("ALIGN", (1, 0), (-1, -1), "CENTER"),
        ("TOPPADDING", (0, 0), (-1, -1), 10),
        ("BOTTOMPADDING", (0, 0), (-1, -1), 10),
        ("BACKGROUND", (0, 1), (-1, -1), LIGHT_BG),
        ("LINEBELOW", (0, -1), (-1, -1), 0.5, GRAY),
    ]))
    elements.extend([tbl, Spacer(1, 10)])

    # Summary rows
    tax = subtotal * 0.10
    for label, val in [("Subtotal:", subtotal),
                       ("Tax (10%):", tax)]:
        elements.append(Table(
            [["", "", Paragraph(f"<b>{label}</b>", s["bold"]),
              Paragraph(f"${val:.2f}", s["value"])]],
            colWidths=col_w,
        ))

    elements.append(
        HRFlowable(width="100%", thickness=1, color=DARK))
    total = subtotal + tax
    elements.append(Table(
        [["", "",
          Paragraph("<b>TOTAL DUE:</b>", s["total"]),
          Paragraph(f"<b>${total:.2f} USD</b>", s["total"])]],
        colWidths=col_w,
    ))

    doc.build(elements)
    print(f"Created: {output_path}")


if __name__ == "__main__":
    p = argparse.ArgumentParser()
    p.add_argument("--client", required=True)
    p.add_argument("--items", required=True,
        help='JSON: [{"description":"...","hours":N,"rate":N}]')
    p.add_argument("--output", required=True)
    a = p.parse_args()
    build_invoice(
        a.client, json.loads(a.items),
        os.path.expanduser(a.output),
    )