"""
PDF-Bericht aus ReportProfilePayload: ReportLab für Text/Layout, Matplotlib für Chart-Payloads.
"""
from __future__ import annotations

import io
import logging
from typing import Any
from xml.sax.saxutils import escape

from reportlab.lib.pagesizes import A4
from reportlab.lib.styles import getSampleStyleSheet
from reportlab.lib.units import mm
from reportlab.platypus import Image as RLImage
from reportlab.platypus import Paragraph, SimpleDocTemplate, Spacer

from db import get_cursor, get_db
from report_chart_fetch import fetch_chart_payload
from report_chart_plotting import chart_payload_to_png
from report_profile_schema import (
    AiInsightBlock,
    ChartBlock,
    ReportProfilePayload,
    SectionBlock,
    VizBundleBlock,
)
from report_viz_bundle_pdf import append_viz_bundle_to_story

logger = logging.getLogger(__name__)

_CONTENT_TRUNCATE = 12000


def _insight_text(profile_id: str, insight_id: str | None) -> tuple[str, str]:
    """Returns (heading, body_text)."""
    if not insight_id:
        return (
            "KI-Auswertung",
            "(Noch keine Auswahl — in einer späteren Version kannst du hier eine gespeicherte KI-Analyse "
            "verknüpfen.)",
        )
    try:
        with get_db() as conn:
            cur = get_cursor(conn)
            cur.execute(
                "SELECT scope, content, created FROM ai_insights WHERE id = %s AND profile_id = %s",
                (insight_id, profile_id),
            )
            row = cur.fetchone()
            if not row:
                return ("KI-Auswertung", "Eintrag nicht gefunden oder keine Berechtigung.")
            scope = row.get("scope") or "Analyse"
            content = row.get("content") or ""
            if len(content) > _CONTENT_TRUNCATE:
                content = content[:_CONTENT_TRUNCATE] + "\n\n[… gekürzt …]"
            created = row.get("created")
            sub = f"{scope}" + (f" · {created}" if created else "")
            return (sub, content)
    except Exception as e:
        logger.warning("report pdf insight load failed: %s", e)
        return ("KI-Auswertung", "Fehler beim Laden des Eintrags.")


def build_structured_report_pdf(
    *,
    profile_id: str,
    profile_name: str,
    payload: ReportProfilePayload,
) -> bytes:
    """Vollständiges PDF als Bytes (A4)."""
    buf = io.BytesIO()
    doc = SimpleDocTemplate(
        buf,
        pagesize=A4,
        leftMargin=14 * mm,
        rightMargin=14 * mm,
        topMargin=16 * mm,
        bottomMargin=16 * mm,
    )
    styles = getSampleStyleSheet()
    story: list[Any] = []

    title = (payload.document_title or "").strip() or f"{profile_name} – Bericht"
    story.append(Paragraph(escape(title), styles["Title"]))
    story.append(Spacer(1, 6 * mm))

    for block in payload.blocks:
        if isinstance(block, SectionBlock):
            story.append(Spacer(1, 4 * mm))
            story.append(Paragraph(escape(block.title), styles["Heading2"]))
            story.append(Spacer(1, 2 * mm))
        elif isinstance(block, VizBundleBlock):
            append_viz_bundle_to_story(story, styles, profile_id, block.bundle_id, block.config)
        elif isinstance(block, ChartBlock):
            try:
                chart = fetch_chart_payload(block.chart_id, profile_id, block.window_days)
            except Exception as e:
                logger.warning("chart fetch %s: %s", block.chart_id, e)
                story.append(Paragraph(f"Diagramm {block.chart_id}: Fehler bei Daten.", styles["Normal"]))
                continue
            meta = chart.get("metadata") or {}
            if meta.get("confidence") == "insufficient":
                msg = meta.get("message") or "Nicht genug Daten"
                story.append(Paragraph(f"<i>{block.chart_id}</i>: {msg}", styles["Normal"]))
                story.append(Spacer(1, 3 * mm))
                continue
            try:
                png = chart_payload_to_png(chart)
                img_buf = io.BytesIO(png)
                iw = 170 * mm
                ih = 85 * mm
                story.append(RLImage(img_buf, width=iw, height=ih))
            except Exception as e:
                logger.warning("chart render %s: %s", block.chart_id, e)
                story.append(Paragraph(f"Diagramm {block.chart_id}: Darstellung fehlgeschlagen.", styles["Normal"]))
            story.append(Spacer(1, 4 * mm))
        elif isinstance(block, AiInsightBlock):
            heading, body = _insight_text(profile_id, block.insight_id)
            if block.title.strip():
                story.append(Paragraph(escape(block.title), styles["Heading3"]))
            else:
                story.append(Paragraph(escape(heading), styles["Heading3"]))
            for para in body.split("\n\n"):
                p = (para or "").strip()
                if p:
                    story.append(Paragraph(escape(p), styles["BodyText"]))
            story.append(Spacer(1, 4 * mm))

    doc.build(story)
    return buf.getvalue()