# src/pdf_utils.py

from io import BytesIO
from reportlab.lib.pagesizes import A4
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
from reportlab.lib.units import inch
import os

# ---------------- FONT REGISTRATION ----------------

FONT_DIR = "src/fonts"

REGULAR_FONT = os.path.join(FONT_DIR, "NotoSansTamil-Regular.ttf")
BOLD_FONT = os.path.join(FONT_DIR, "NotoSansTamil-Bold.ttf")

pdfmetrics.registerFont(TTFont("Tamil", REGULAR_FONT))
pdfmetrics.registerFont(TTFont("Tamil-Bold", BOLD_FONT))

# ---------------- PDF GENERATOR ----------------

def answer_to_pdf(question: str, answer: str) -> BytesIO:
    buffer = BytesIO()

    doc = SimpleDocTemplate(
        buffer,
        pagesize=A4,
        rightMargin=72,
        leftMargin=72,
        topMargin=72,
        bottomMargin=72,
    )

    styles = getSampleStyleSheet()

    styles.add(
        ParagraphStyle(
            name="TitleStyle",
            fontName="Tamil-Bold",
            fontSize=14,
            spaceAfter=12,
        )
    )

    styles.add(
        ParagraphStyle(
            name="HeadingStyle",
            fontName="Tamil-Bold",
            fontSize=11,
            spaceAfter=6,
        )
    )

    styles.add(
        ParagraphStyle(
            name="BodyStyle",
            fontName="Tamil",
            fontSize=11,
            leading=14,
            spaceAfter=6,
        )
    )

    story = []

    # ---------- Title ----------
    story.append(Paragraph("OTT Bot – Answer", styles["TitleStyle"]))
    story.append(Spacer(1, 12))

    # ---------- Question ----------
    story.append(Paragraph("Question:", styles["HeadingStyle"]))
    story.append(Paragraph(question.replace("\n", "<br/>"), styles["BodyStyle"]))
    story.append(Spacer(1, 12))

    # ---------- Answer ----------
    story.append(Paragraph("Answer:", styles["HeadingStyle"]))
    story.append(Paragraph(answer.replace("\n", "<br/>"), styles["BodyStyle"]))

    doc.build(story)

    buffer.seek(0)
    return buffer