genbill.py

import os
import zipfile
import json
from num2words import num2words
import pendulum
import subprocess


TEMPLATE_DOC = "InvoiceTemplate.docx"
DATE_FMT = "YYYY-MMM-DD"
close_tr = "</w:tr>"
open_tr = "<w:tr>"
br = '</w:t><w:br /><w:t xml:space="preserve">'


def as_money(num):
    result = ""
    for i, c in enumerate(reversed(list(str(num)))):
        if i in [3, 5, 7, 9]:
            result += ","
        result += c
    return "".join(reversed(list(result))) + "/-"


def get_row_template(doc):
    row_start = -1
    desc_start = doc.index("{{ ITEM_DESCRIPTION }}")
    while True:
        new_start = doc.index(open_tr, row_start + 1)
        if new_start >= desc_start:
            break
        row_start = new_start
    row_end = doc.index(close_tr, desc_start)
    return doc[row_start : row_end + len(close_tr)]


def docx_replace(old_file, new_file, rep):
    print(old_file, new_file)
    zin = zipfile.ZipFile(old_file, "r")
    zout = zipfile.ZipFile(new_file, "w")
    for item in zin.infolist():
        buffer = zin.read(item.filename)
        if item.filename == "word/document.xml":
            res = buffer.decode("utf-8")
            for r in rep:
                if r == "{{ ITEMS }}":
                    last_tr = None
                    row_template = None
                    for nth_item, bill_item in enumerate(rep[r]):
                        bill_item["{{ SR_NO }}"] = nth_item + 1
                        if nth_item == 0:
                            last_tr = res.index("{{ ITEM_DESCRIPTION }}")
                            row_template = get_row_template(res)
                            for k, v in bill_item.items():
                                res = res.replace(k, f"{v}")
                            last_tr = res.index(close_tr, last_tr)
                            last_tr += len(close_tr)
                        else:
                            nr = row_template.replace(
                                "{{ ITEM_SR }}", str(nth_item + 1)
                            )
                            for k, v in bill_item.items():
                                nr = nr.replace(k, f"{v}")
                            res = res[:last_tr] + nr + res[last_tr:]
                            last_tr += len(nr)
                else:
                    if res != res.replace(r, rep[r]):
                        res = res.replace(r, rep[r])
            buffer = res.encode("utf-8")
        zout.writestr(item, buffer)
    zout.close()
    zin.close()
    print("Wrote file")


def make_bill(invoice_number, bill_to, items, pay_to_details, gen_on):
    assert invoice_number
    fname = invoice_number.replace("/", "_")
    if os.path.exists(f"bills/{fname}.pdf"):
        print(f"Already generated: {fname}")
        return
    gen_on = pendulum.parse(gen_on)
    pay_before = gen_on.add(days=7).format(DATE_FMT)
    gen_on = gen_on.format(DATE_FMT)
    config = {}
    # -- calculate item totals
    total = 0
    for item in items:
        if "item_qty" not in item:
            item["item_rate"] = item["item_amt"]
            item["item_qty"] = 1
        else:
            item["item_amt"] = item["item_rate"] * item["item_qty"]
        total += item["item_amt"]
        item["item_amt"] = as_money(item["item_amt"])
        for key in list(item.keys()):
            ckey = "{{ " + key.upper() + " }}"
            item[ckey] = str(item.pop(key))
    total_words = num2words(total, lang="en_IN") + " only"
    total_words = total_words.capitalize()
    total = as_money(total)
    # -- set context for docx template filling
    for key in locals():
        if key in {
            "items",
            "gen_on",
            "pay_before",
            "bill_to",
            "invoice_number",
            "pay_to_details",
            "total",
            "total_words",
        }:
            ckey = "{{ " + key.upper() + " }}"
            config[ckey] = locals()[key]
    docx_replace(TEMPLATE_DOC, f"bills/{fname}.docx", config)
    subprocess.run(
        f"libreoffice --headless --convert-to pdf bills/{fname}.docx --outdir bills && rm bills/{fname}.docx",
        shell=True,
    )


if __name__ == "__main__":
    from bills import bills

    for bill in bills:
        make_bill(**bill._asdict())