"""
Generate the CRTC Registration Notification Letter as a DOCX file.

This produces a formal letter addressed to the Secretary General of the CRTC
notifying them that a new telecommunications service provider has been
established under a BC corporation and wishes to register as a:
  - Voice, Data & Wireless Reseller (domestic)
  - Basic International Telecommunications Service (BITS) provider (if applicable)

The letter follows the format specified at:
  https://crtc.gc.ca/eng/comm/telecom/registr4.htm

Usage:
    from scripts.document_gen.templates.crtc_letter_generator import generate_crtc_letter
    pdf_path = generate_crtc_letter(
        entity_name="1234567 B.C. Ltd.",
        incorporation_number="1234567",
        registered_office="329 Howe St, Vancouver, BC V6C 3N2",
        services_description="Resale of voice, data, and wireless services...",
        geographic_coverage="BC and Worldwide",
        include_bits=True,
        regulatory_contact_name="Regulatory Director",
        regulatory_contact_email="regulatory@example.ca",
        regulatory_contact_phone="+16045551234",
        director_name="John Doe",
        output_path="/tmp/crtc_letter.docx",
    )
"""
from __future__ import annotations

import logging
import os
from datetime import datetime
from pathlib import Path
from typing import Optional

LOG = logging.getLogger("document_gen.crtc_letter")

try:
    from docx import Document
    from docx.shared import Pt, Inches, RGBColor
    from docx.enum.text import WD_ALIGN_PARAGRAPH
except ImportError:
    LOG.warning("python-docx not installed — CRTC letter generation unavailable")
    Document = None


def generate_crtc_letter(
    entity_name: str,
    incorporation_number: str,
    registered_office: str,
    services_description: str,
    geographic_coverage: str = "Canada-wide",
    include_bits: bool = True,
    regulatory_contact_name: str = "Regulatory Director",
    regulatory_contact_email: str = "",
    regulatory_contact_phone: str = "",
    director_name: str = "",
    ca_domain: str = "",
    output_path: str = "/tmp/crtc_notification_letter.docx",
) -> Optional[str]:
    """
    Generate a CRTC Registration Notification Letter as a DOCX file.

    Returns the output file path on success, None on failure.
    """
    if Document is None:
        LOG.error("python-docx not installed")
        return None

    doc = Document()

    # Page margins
    for section in doc.sections:
        section.top_margin = Inches(1)
        section.bottom_margin = Inches(1)
        section.left_margin = Inches(1.25)
        section.right_margin = Inches(1.25)

    # ── Sender block ──────────────────────────────────────────
    today = datetime.now().strftime("%B %d, %Y")

    sender = doc.add_paragraph()
    sender.alignment = WD_ALIGN_PARAGRAPH.LEFT
    sender_run = sender.add_run(
        f"{entity_name}\n"
        f"Incorporation No. {incorporation_number}\n"
        f"{registered_office}\n"
    )
    sender_run.font.size = Pt(10)
    if regulatory_contact_phone:
        sender.add_run(f"Tel: {regulatory_contact_phone}\n").font.size = Pt(10)
    if regulatory_contact_email:
        sender.add_run(f"Email: {regulatory_contact_email}\n").font.size = Pt(10)
    if ca_domain:
        sender.add_run(f"Web: https://{ca_domain}\n").font.size = Pt(10)

    # Date
    date_para = doc.add_paragraph()
    date_para.alignment = WD_ALIGN_PARAGRAPH.LEFT
    date_run = date_para.add_run(today)
    date_run.font.size = Pt(10)

    # ── Addressee ─────────────────────────────────────────────
    doc.add_paragraph()
    addressee = doc.add_paragraph()
    addressee_run = addressee.add_run(
        "Secretary General\n"
        "Canadian Radio-television and\n"
        "Telecommunications Commission (CRTC)\n"
        "Ottawa, Ontario\n"
        "K1A 0N2"
    )
    addressee_run.font.size = Pt(10)

    # ── Subject line ──────────────────────────────────────────
    doc.add_paragraph()
    subject = doc.add_paragraph()
    subject_run = subject.add_run(
        f"Re: Registration as a Telecommunications Service Provider — {entity_name}"
    )
    subject_run.font.size = Pt(10)
    subject_run.bold = True

    # ── Body ──────────────────────────────────────────────────
    doc.add_paragraph()

    # Introduction
    intro = doc.add_paragraph()
    intro_run = intro.add_run(
        f"Dear Secretary General,\n\n"
        f"Pursuant to the Telecommunications Act, S.C. 1993, c. 38, and the "
        f"Canadian Radio-television and Telecommunications Commission's registration "
        f"requirements for telecommunications service providers, {entity_name} "
        f"(Incorporation No. {incorporation_number}) hereby notifies the Commission of its "
        f"intention to provide telecommunications services in Canada."
    )
    intro_run.font.size = Pt(10)

    # Company information section
    doc.add_paragraph()
    info_heading = doc.add_paragraph()
    info_heading_run = info_heading.add_run("1. Company Information")
    info_heading_run.font.size = Pt(10)
    info_heading_run.bold = True

    info = doc.add_paragraph()
    info.style.font.size = Pt(10)
    info_text = (
        f"Legal Name: {entity_name}\n"
        f"Incorporation Number: {incorporation_number}\n"
        f"Mailing Address: {registered_office}\n"
        f"Telephone: {regulatory_contact_phone}\n"
        f"Email: {regulatory_contact_email}\n"
    )
    info.add_run(info_text).font.size = Pt(10)

    # Services section
    doc.add_paragraph()
    svc_heading = doc.add_paragraph()
    svc_heading_run = svc_heading.add_run("2. Description of Services")
    svc_heading_run.font.size = Pt(10)
    svc_heading_run.bold = True

    svc = doc.add_paragraph()
    svc.add_run(
        f"{entity_name} intends to operate as a reseller of voice, data, and wireless "
        f"telecommunications services. Specifically:\n\n"
        f"{services_description}\n\n"
        f"Geographic Coverage: {geographic_coverage}"
    ).font.size = Pt(10)

    # Registration type
    doc.add_paragraph()
    reg_heading = doc.add_paragraph()
    reg_heading_run = reg_heading.add_run("3. Registration Category")
    reg_heading_run.font.size = Pt(10)
    reg_heading_run.bold = True

    reg = doc.add_paragraph()
    reg_text = f"{entity_name} registers as a Voice, Data & Wireless Reseller."
    if include_bits:
        reg_text += (
            f"\n\n{entity_name} also intends to provide Basic International "
            f"Telecommunications Services (BITS) and will file a separate notification "
            f"with the Commission pursuant to CRTC Telecom Decision 98-17."
        )
    reg.add_run(reg_text).font.size = Pt(10)

    # Response Manager
    doc.add_paragraph()
    rm_heading = doc.add_paragraph()
    rm_heading_run = rm_heading.add_run("4. Response Manager for Regulatory Matters")
    rm_heading_run.font.size = Pt(10)
    rm_heading_run.bold = True

    rm = doc.add_paragraph()
    rm.add_run(
        f"Name: {regulatory_contact_name}\n"
        f"Title: Regulatory Director\n"
        f"Organization: {entity_name}\n"
        f"Address: {registered_office}\n"
        f"Telephone: {regulatory_contact_phone}\n"
        f"Email: {regulatory_contact_email}"
    ).font.size = Pt(10)

    # Compliance commitment
    doc.add_paragraph()
    compliance_heading = doc.add_paragraph()
    compliance_heading_run = compliance_heading.add_run("5. Compliance")
    compliance_heading_run.font.size = Pt(10)
    compliance_heading_run.bold = True

    compliance = doc.add_paragraph()
    compliance.add_run(
        f"{entity_name} confirms that it will comply with all applicable provisions of "
        f"the Telecommunications Act, CRTC regulations, and conditions of service, "
        f"including participation in the Commission for Complaints for "
        f"Telecom-Television Services (CCTS)."
    ).font.size = Pt(10)

    # Closing
    doc.add_paragraph()
    doc.add_paragraph()
    closing = doc.add_paragraph()
    closing.add_run("Respectfully submitted,").font.size = Pt(10)

    # Signature block (space for eSign)
    doc.add_paragraph()
    doc.add_paragraph()  # Space for signature
    doc.add_paragraph()

    sig_line = doc.add_paragraph()
    sig_line.add_run("_" * 40).font.size = Pt(10)

    sig_name = doc.add_paragraph()
    sig_name_run = sig_name.add_run(director_name or regulatory_contact_name)
    sig_name_run.font.size = Pt(10)
    sig_name_run.bold = True

    sig_title = doc.add_paragraph()
    sig_title.add_run(f"Director, {entity_name}").font.size = Pt(10)

    sig_date = doc.add_paragraph()
    sig_date.add_run(f"Date: {today}").font.size = Pt(10)

    # Save
    output = Path(output_path)
    output.parent.mkdir(parents=True, exist_ok=True)
    doc.save(str(output))
    LOG.info("CRTC letter generated: %s", output)
    return str(output)