"""Render an assembled report dict (from reporting.build_report) to a real PDF using reportlab.

Kept separate from reporting.py so the core assembly stays dependency-free and testable."""

from __future__ import annotations

import io

def render_pdf(report: dict) -> bytes:

    from reportlab.lib import colors

    from reportlab.lib.pagesizes import letter

    from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle

    from reportlab.lib.units import inch

    from reportlab.platypus import (

        SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,

    )

    buf = io.BytesIO()

    doc = SimpleDocTemplate(buf, pagesize=letter, title=report.get("title", "Report"),

                            topMargin=0.7 * inch, bottomMargin=0.7 * inch)

    styles = getSampleStyleSheet()

    h1 = styles["Title"]

    h2 = ParagraphStyle("H2", parent=styles["Heading2"], spaceBefore=14, textColor=colors.HexColor("#1a3a5a"))

    body = styles["BodyText"]

    story = [Paragraph(report.get("title", "Investigation Report"), h1), Spacer(1, 10)]

    for key, content in report.get("sections", {}).items():

        story.append(Paragraph(key.replace("_", " ").title(), h2))

        if isinstance(content, str):

            story.append(Paragraph(content, body))

        elif isinstance(content, list):

            if content and isinstance(content[0], dict):

                cols = list(content[0].keys())

                data = [cols] + [[_cell(row.get(c)) for c in cols] for row in content[:60]]

                story.append(_table(data, Table, TableStyle, colors))

            else:

                for item in content:

                    story.append(Paragraph(f"• {_cell(item)}", body))

        elif isinstance(content, dict):

            data = [["Field", "Value"]] + [[k, _cell(v)] for k, v in content.items()]

            story.append(_table(data, Table, TableStyle, colors))

        story.append(Spacer(1, 6))

    doc.build(story)

    return buf.getvalue()

def _cell(v) -> str:

    import json

    if isinstance(v, (dict, list)):

        return json.dumps(v, default=str)[:120]

    return str(v) if v is not None else "-"

def _table(data, Table, TableStyle, colors):

    t = Table(data, repeatRows=1, hAlign="LEFT")

    t.setStyle(TableStyle([

        ("BACKGROUND", (0, 0), (-1, 0), colors.HexColor("#1a3a5a")),

        ("TEXTCOLOR", (0, 0), (-1, 0), colors.white),

        ("FONTSIZE", (0, 0), (-1, -1), 7),

        ("GRID", (0, 0), (-1, -1), 0.4, colors.HexColor("#cccccc")),

        ("ROWBACKGROUNDS", (0, 1), (-1, -1), [colors.white, colors.HexColor("#f2f6fa")]),

        ("VALIGN", (0, 0), (-1, -1), "TOP"),

    ]))

    return t