"""
Cover-page generator for transcript and summary DOCX files.

Layout (all centered):
- 5 blank lines
- 3 blank lines
- Title in uppercase: "TRANSCRIPT" or "SUMMARY"
- Next line: date of transcription (e.g. "June 19, 2026")
- Next line: "Created by <COVER_PAGE_ORGANIZATION>"
- 3 blank lines
- Disclaimer (underlined)
- Page break (ensures content starts on page 2)

Environment variables:
- COVER_PAGE_ENABLED: "true"/"false" (default: false)
- COVER_PAGE_ORGANIZATION: e.g., "A.P.Strom"
- SERVER_TIMEZONE: Timezone for document dates (e.g., "America/Toronto"). Defaults to "UTC".
"""

import os
from datetime import datetime
from typing import Optional
from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
from docx import Document
from docx.shared import Pt
from docx.enum.text import WD_ALIGN_PARAGRAPH
from docx.oxml import OxmlElement
from docx.oxml.ns import qn


def _get_server_timezone():
    tz_name = (os.getenv("SERVER_TIMEZONE") or "UTC").strip()
    try:
        return ZoneInfo(tz_name)
    except (ZoneInfoNotFoundError, KeyError, ValueError):
        return ZoneInfo("UTC")


def _add_centered_paragraph(doc: Document, text: str = "", font_size: Pt = Pt(12), bold: bool = False, underline: bool = False):
    """Add a centered paragraph with given text and style."""
    p = doc.add_paragraph()
    p.alignment = WD_ALIGN_PARAGRAPH.CENTER
    if text:
        run = p.add_run(text)
        run.font.name = "Courier"
        run.font.size = font_size
        run.bold = bold
        run.underline = underline
    return p


def _add_blank_lines(doc: Document, count: int):
    """Add specified number of blank lines (empty centered paragraphs)."""
    for _ in range(count):
        _add_centered_paragraph(doc)


def _add_page_break(doc: Document):
    """Insert a page break after the last paragraph (no extra blank line)."""
    from docx.enum.text import WD_BREAK
    last_p = doc.paragraphs[-1]
    run = last_p.add_run()
    run.add_break(WD_BREAK.PAGE)


def add_cover_page(
    doc: Document,
    title: str,
    date_str: Optional[str] = None,
):
    """
    Insert a cover page at the current cursor position.

    - title: e.g., "TRANSCRIPT" or "SUMMARY"
    - date_str: optional date string (e.g., "June 19, 2026");
      if not provided, uses current server time in SERVER_TIMEZONE.
    """

    # 3 blank lines
    _add_blank_lines(doc, 3)

    # 3 blank lines
    _add_blank_lines(doc, 3)

    # Title in uppercase
    _add_centered_paragraph(doc, text=title.upper().strip(), font_size=Pt(18), bold=True)

    # Date of transcription
    if not date_str:
        tz = _get_server_timezone()
        now = datetime.now(tz)
        date_str = now.strftime("%B %d, %Y")
    _add_centered_paragraph(doc, text=f"Transcript created on: {date_str}", font_size=Pt(14))

    # Transcribed by + organization
    org = (os.getenv("COVER_PAGE_ORGANIZATION") or "").strip()
    if org:
        _add_centered_paragraph(doc, text=f"Transcribed by {org}", font_size=Pt(12))

    # 3 blank lines
    _add_blank_lines(doc, 3)

    # Disclaimer
    disclaimer_title = "Disclaimer"
    disclaimer_body = (
        "This transcription and any summary derived therefrom are created entirely by large language models. "
        "Large language models are imperfect and may create errors or inaccuracies. "
        "The following transcription and summary (if applicable) are designed to assist users. "
        "They are not a conclusive record or summary of what transpired in an audio recording. "
        "Use at your own risk."
    )

    # Underlined "Disclaimer" line
    p = _add_centered_paragraph(doc, text=disclaimer_title, font_size=Pt(10), underline=True)

    # Body text (not underlined)
    _add_centered_paragraph(doc, text=disclaimer_body, font_size=Pt(10), underline=False)

    # Page break after cover page so main content starts on page 2
    _add_page_break(doc)