"""
PDF Service — Visit Report Generation (ReportLab)

Generates a structured PDF report for a visit including:
- Visit details (title, location, date, status)
- Checklist items with check/uncheck status and notes
- Photo metadata table
- Summary statistics

Dependency: reportlab, pillow
Install: pip install reportlab pillow
"""

import io
import logging
import uuid
from datetime import datetime
from typing import Optional

from reportlab.lib import colors
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_RIGHT
from reportlab.lib.pagesizes import A4
from reportlab.lib.styles import ParagraphStyle, getSampleStyleSheet
from reportlab.lib.units import mm
from reportlab.platypus import (
    HRFlowable,
    Paragraph,
    SimpleDocTemplate,
    Spacer,
    Table,
    TableStyle,
)

from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from sqlalchemy.orm import selectinload

from models.visit_model import Visit
from models.checklist_model import Checklist
from models.photo_model import Photo
from models.assessment_model import Assessment

logger = logging.getLogger(__name__)

# ── Color Palette ──────────────────────────────────────────────────────────
PRIMARY   = colors.HexColor("#1565C0")   # Material Blue 800
SUCCESS   = colors.HexColor("#2E7D32")   # Green 800
WARNING   = colors.HexColor("#F57F17")   # Amber 800
DANGER    = colors.HexColor("#C62828")   # Red 800
GREY_LIGHT = colors.HexColor("#F5F5F5")
GREY_TEXT  = colors.HexColor("#757575")
ORANGE    = colors.HexColor("#F57F17")
PURPLE    = colors.HexColor("#7B1FA2")

# Assessment category colors
CAT_COLORS = {
    "A": colors.HexColor("#1976D2"),  # Blue
    "B": colors.HexColor("#F57C00"),  # Orange
    "C": colors.HexColor("#00897B"),  # Teal
    "D": colors.HexColor("#2E7D32"),  # Green
    "E": colors.HexColor("#7B1FA2"),  # Purple
}
CAT_LABELS = {
    "A": "Pelayanan Awal",
    "B": "Kualitas Produk",
    "C": "Kebersihan & Suasana",
    "D": "Kepatuhan SOP",
    "E": "Keseluruhan Pengalaman",
}


class PDFService:
    """Generates PDF visit reports using ReportLab."""

    def _build_styles(self):
        """Create custom paragraph styles for the report."""
        base = getSampleStyleSheet()
        return {
            "title": ParagraphStyle(
                "ReportTitle",
                parent=base["Title"],
                fontSize=20,
                textColor=PRIMARY,
                spaceAfter=4,
            ),
            "subtitle": ParagraphStyle(
                "Subtitle",
                parent=base["Normal"],
                fontSize=10,
                textColor=GREY_TEXT,
                spaceAfter=12,
            ),
            "section": ParagraphStyle(
                "SectionHeader",
                parent=base["Heading2"],
                fontSize=12,
                textColor=PRIMARY,
                spaceBefore=12,
                spaceAfter=6,
            ),
            "body": ParagraphStyle(
                "Body",
                parent=base["Normal"],
                fontSize=9,
                leading=14,
            ),
            "label": ParagraphStyle(
                "Label",
                parent=base["Normal"],
                fontSize=8,
                textColor=GREY_TEXT,
            ),
        }

    def _status_color(self, status: str) -> colors.Color:
        return {
            "completed": SUCCESS,
            "in_progress": WARNING,
            "cancelled": DANGER,
        }.get(status, GREY_TEXT)

    def _score_color(self, score: float) -> colors.Color:
        """Color based on normalized score."""
        if score >= 4.5:
            return SUCCESS
        elif score >= 3.5:
            return colors.HexColor("#558B2F")
        elif score >= 2.5:
            return WARNING
        else:
            return DANGER

    async def generate_visit_report(
        self, db: AsyncSession, visit_id: uuid.UUID
    ) -> Optional[bytes]:
        """
        Generate a PDF report for a visit.

        Args:
            db: Async DB session
            visit_id: UUID of the visit

        Returns:
            PDF as bytes, or None if visit not found
        """
        logger.info(f"Generating PDF for visit: {visit_id}")

        # ── Load visit with relations ──
        result = await db.execute(
            select(Visit)
            .options(
                selectinload(Visit.checklists),
                selectinload(Visit.photos),
                selectinload(Visit.assessments),
            )
            .where(Visit.id == visit_id)
        )
        visit = result.scalar_one_or_none()
        if not visit:
            logger.warning(f"Visit {visit_id} not found for PDF generation")
            return None

        # ── Build PDF in memory ──
        buffer = io.BytesIO()
        doc = SimpleDocTemplate(
            buffer,
            pagesize=A4,
            rightMargin=20 * mm,
            leftMargin=20 * mm,
            topMargin=20 * mm,
            bottomMargin=20 * mm,
        )

        styles = self._build_styles()
        story = []

        # ── Header ────────────────────────────────────────────
        story.append(Paragraph(visit.title, styles["title"]))
        story.append(Paragraph(
            f"Laporan Kunjungan  •  Dicetak {datetime.utcnow().strftime('%d %b %Y %H:%M')} UTC",
            styles["subtitle"],
        ))
        story.append(HRFlowable(width="100%", thickness=1, color=PRIMARY))
        story.append(Spacer(1, 6 * mm))

        # ── Visit Details Table ────────────────────────────────
        story.append(Paragraph("Informasi Kunjungan", styles["section"]))

        status_label = visit.status.replace("_", " ").title()
        details_data = [
            ["Nama Outlet", visit.location or "—"],
            ["Nama Ghost Shopper", visit.ghost_shopper or "—"],
            ["Tanggal Kunjungan", visit.visit_date.strftime("%d %b %Y %H:%M")],
            ["Tipe Kunjungan", visit.visit_type.replace('_', ' ').title() if visit.visit_type else "Dine In"],
            ["Status Laporan", status_label],
        ]

        details_table = Table(
            details_data,
            colWidths=[45 * mm, 125 * mm],
        )
        details_table.setStyle(TableStyle([
            ("BACKGROUND",   (0, 0), (0, -1), GREY_LIGHT),
            ("TEXTCOLOR",    (0, 0), (-1, -1), colors.black),
            ("FONTSIZE",     (0, 0), (-1, -1), 9),
            ("FONTNAME",     (0, 0), (0, -1), "Helvetica-Bold"),
            ("GRID",         (0, 0), (-1, -1), 0.5, colors.HexColor("#E0E0E0")),
            ("LEFTPADDING",  (0, 0), (-1, -1), 8),
            ("RIGHTPADDING", (0, 0), (-1, -1), 8),
            ("TOPPADDING",   (0, 0), (-1, -1), 5),
            ("BOTTOMPADDING",(0, 0), (-1, -1), 5),
            # Status cell color
            ("TEXTCOLOR",    (1, 4), (1, 4), self._status_color(visit.status)),
            ("FONTNAME",     (1, 4), (1, 4), "Helvetica-Bold"),
        ]))
        story.append(details_table)
        story.append(Spacer(1, 6 * mm))

        # ── Ghost Shopper Assessment Section ──────────────────
        assessments = visit.assessments or []
        if assessments:
            # Group by category
            cat_groups = {}
            for a in assessments:
                cat_groups.setdefault(a.category, []).append(a)

            total_score = sum(a.score for a in assessments)
            overall_avg = round(total_score / len(assessments), 2)

            story.append(Paragraph(
                f"Hasil Penilaian Ghost Shopper (Skor Rata-Rata: {overall_avg}/5.0)",
                styles["section"],
            ))

            # Category summary table
            cat_header = [["Kategori", "Deskripsi", "Jml Item", "Rata-Rata Skor"]]
            for cat_key in sorted(cat_groups.keys()):
                items = cat_groups[cat_key]
                cat_avg = round(sum(i.score for i in items) / len(items), 2)
                cat_header.append([
                    cat_key,
                    CAT_LABELS.get(cat_key, cat_key),
                    str(len(items)),
                    str(cat_avg),
                ])
            cat_header.append(["", "KESELURUHAN", str(len(assessments)), str(overall_avg)])

            cat_table = Table(cat_header, colWidths=[18*mm, 70*mm, 20*mm, 62*mm])
            cat_styles = [
                ("BACKGROUND",   (0, 0), (-1, 0), PRIMARY),
                ("TEXTCOLOR",    (0, 0), (-1, 0), colors.white),
                ("FONTNAME",     (0, 0), (-1, 0), "Helvetica-Bold"),
                ("FONTSIZE",     (0, 0), (-1, -1), 9),
                ("GRID",         (0, 0), (-1, -1), 0.5, colors.HexColor("#E0E0E0")),
                ("LEFTPADDING",  (0, 0), (-1, -1), 6),
                ("TOPPADDING",   (0, 0), (-1, -1), 4),
                ("BOTTOMPADDING",(0, 0), (-1, -1), 4),
                ("ROWBACKGROUNDS", (0, 1), (-1, -1), [colors.white, GREY_LIGHT]),
                # Overall row bold
                ("FONTNAME",     (0, -1), (-1, -1), "Helvetica-Bold"),
                ("BACKGROUND",   (0, -1), (-1, -1), colors.HexColor("#E3F2FD")),
            ]
            # Color-code each category score
            for i, cat_key in enumerate(sorted(cat_groups.keys()), 1):
                items = cat_groups[cat_key]
                cat_avg = sum(it.score for it in items) / len(items)
                cat_styles.append(("TEXTCOLOR", (3, i), (3, i), self._score_color(cat_avg)))
                cat_styles.append(("FONTNAME",  (3, i), (3, i), "Helvetica-Bold"))
                cat_styles.append(("TEXTCOLOR", (0, i), (0, i), CAT_COLORS.get(cat_key, GREY_TEXT)))
                cat_styles.append(("FONTNAME",  (0, i), (0, i), "Helvetica-Bold"))
            # Overall score color
            cat_styles.append(("TEXTCOLOR", (3, -1), (3, -1), self._score_color(overall_avg)))

            cat_table.setStyle(TableStyle(cat_styles))
            story.append(cat_table)
            story.append(Spacer(1, 4 * mm))

            # Detailed items per category
            for cat_key in sorted(cat_groups.keys()):
                items = sorted(cat_groups[cat_key], key=lambda x: x.item_no)
                cat_avg = round(sum(i.score for i in items) / len(items), 2)
                cat_color = CAT_COLORS.get(cat_key, PRIMARY)

                story.append(Paragraph(
                    f"{cat_key}. {CAT_LABELS.get(cat_key, cat_key)} — Rata-Rata: {cat_avg}/5.0",
                    ParagraphStyle(
                        "CatSub", parent=getSampleStyleSheet()["Normal"],
                        fontSize=9, textColor=cat_color,
                        fontName="Helvetica-Bold", spaceBefore=4, spaceAfter=3,
                    ),
                ))

                cell_style = ParagraphStyle(
                    "TableCell",
                    parent=getSampleStyleSheet()["Normal"],
                    fontSize=8,
                    leading=10,
                )

                item_data = [["No.", "Aspek Penilaian", "Skor/Nilai", "Keterangan"]]
                for it in items:
                    if cat_key == "D":
                        score_text = "Ya" if it.score >= 1.0 else "Tidak"
                    else:
                        score_text = str(round(it.score, 1))

                    item_data.append([
                        str(it.item_no),
                        Paragraph(it.criteria, cell_style),
                        score_text,
                        Paragraph(it.raw_value or "—", cell_style),
                    ])

                item_table = Table(item_data, colWidths=[10*mm, 85*mm, 25*mm, 50*mm])
                item_styles = [
                    ("BACKGROUND",   (0, 0), (-1, 0), cat_color),
                    ("TEXTCOLOR",    (0, 0), (-1, 0), colors.white),
                    ("FONTNAME",     (0, 0), (-1, 0), "Helvetica-Bold"),
                    ("FONTSIZE",     (0, 0), (-1, -1), 8),
                    ("GRID",         (0, 0), (-1, -1), 0.5, colors.HexColor("#E0E0E0")),
                    ("ROWBACKGROUNDS", (0, 1), (-1, -1), [colors.white, GREY_LIGHT]),
                    ("LEFTPADDING",  (0, 0), (-1, -1), 4),
                    ("TOPPADDING",   (0, 0), (-1, -1), 3),
                    ("BOTTOMPADDING",(0, 0), (-1, -1), 3),
                    ("VALIGN",       (0, 0), (-1, -1), "TOP"),
                ]
                # Color-code individual scores
                for i, it in enumerate(items, 1):
                    item_styles.append(("TEXTCOLOR", (2, i), (2, i), self._score_color(it.score)))
                    item_styles.append(("FONTNAME",  (2, i), (2, i), "Helvetica-Bold"))

                item_table.setStyle(TableStyle(item_styles))
                story.append(item_table)
                story.append(Spacer(1, 2 * mm))

            story.append(Spacer(1, 4 * mm))

        # ── Comments & Suggestions ────────────────────────────
        if visit.comments or visit.suggestions:
            story.append(Paragraph("Komentar & Saran Khusus", styles["section"]))
            if visit.comments:
                story.append(Paragraph(
                    f"<b>Komentar:</b> {visit.comments}", styles["body"]
                ))
                story.append(Spacer(1, 2 * mm))
            if visit.suggestions:
                story.append(Paragraph(
                    f"<b>Saran:</b> {visit.suggestions}", styles["body"]
                ))
            story.append(Spacer(1, 6 * mm))

        # ── Checklist Section ─────────────────────────────────
        checklists = visit.checklists
        checked_count = sum(1 for c in checklists if c.is_checked)
        total_count = len(checklists)
        pct = round(checked_count / total_count * 100) if total_count > 0 else 0

        story.append(Paragraph(
            f"Daftar Periksa (Checklist) ({checked_count}/{total_count} — {pct}% selesai)",
            styles["section"],
        ))

        if checklists:
            cl_data = [["No", "Status", "Item", "Catatan", "Waktu Cek"]]
            for i, item in enumerate(checklists, 1):
                status_mark = "SELESAI" if item.is_checked else "TERTUNDA"
                checked_at = (
                    item.checked_at.strftime("%d %b %Y")
                    if item.checked_at else "—"
                )
                cl_data.append([
                    str(i),
                    status_mark,
                    item.item_name,
                    item.notes or "—",
                    checked_at,
                ])

            cl_table = Table(
                cl_data,
                colWidths=[8 * mm, 16 * mm, 60 * mm, 60 * mm, 26 * mm],
            )

            # Build row-level styles for checked/unchecked
            row_styles = [
                ("BACKGROUND",   (0, 0), (-1, 0), PRIMARY),
                ("TEXTCOLOR",    (0, 0), (-1, 0), colors.white),
                ("FONTNAME",     (0, 0), (-1, 0), "Helvetica-Bold"),
                ("FONTSIZE",     (0, 0), (-1, -1), 8),
                ("GRID",         (0, 0), (-1, -1), 0.5, colors.HexColor("#E0E0E0")),
                ("LEFTPADDING",  (0, 0), (-1, -1), 5),
                ("RIGHTPADDING", (0, 0), (-1, -1), 5),
                ("TOPPADDING",   (0, 0), (-1, -1), 4),
                ("BOTTOMPADDING",(0, 0), (-1, -1), 4),
                ("ROWBACKGROUNDS", (0, 1), (-1, -1), [colors.white, GREY_LIGHT]),
            ]
            for i, item in enumerate(checklists, 1):
                color = SUCCESS if item.is_checked else DANGER
                row_styles.append(("TEXTCOLOR", (1, i), (1, i), color))
                row_styles.append(("FONTNAME",  (1, i), (1, i), "Helvetica-Bold"))

            cl_table.setStyle(TableStyle(row_styles))
            story.append(cl_table)
        else:
            story.append(Paragraph("Tidak ada riwayat daftar periksa (checklist).", styles["body"]))

        story.append(Spacer(1, 6 * mm))

        # ── Photos Section ─────────────────────────────────────
        story.append(Paragraph(
            f"Lampiran Bukti Foto (Evidence) — {len(visit.photos)} foto terlampir",
            styles["section"],
        ))

        if visit.photos:
            ph_data = [["Nama File", "Ukuran", "Tipe", "Waktu Unggah"]]
            for p in visit.photos:
                size_str = f"{p.file_size // 1024} KB" if p.file_size else "—"
                ph_data.append([
                    p.file_name,
                    size_str,
                    p.mime_type or "—",
                    p.uploaded_at.strftime("%d %b %Y"),
                ])

            ph_table = Table(
                ph_data,
                colWidths=[70 * mm, 25 * mm, 35 * mm, 40 * mm],
            )
            ph_table.setStyle(TableStyle([
                ("BACKGROUND",   (0, 0), (-1, 0), PRIMARY),
                ("TEXTCOLOR",    (0, 0), (-1, 0), colors.white),
                ("FONTNAME",     (0, 0), (-1, 0), "Helvetica-Bold"),
                ("FONTSIZE",     (0, 0), (-1, -1), 8),
                ("GRID",         (0, 0), (-1, -1), 0.5, colors.HexColor("#E0E0E0")),
                ("ROWBACKGROUNDS", (0, 1), (-1, -1), [colors.white, GREY_LIGHT]),
                ("LEFTPADDING",  (0, 0), (-1, -1), 5),
                ("TOPPADDING",   (0, 0), (-1, -1), 4),
                ("BOTTOMPADDING",(0, 0), (-1, -1), 4),
            ]))
            story.append(ph_table)
        else:
            story.append(Paragraph("Tidak ada foto terlampir.", styles["body"]))

        story.append(Spacer(1, 15 * mm))

        # ── Signature Section ──────────────────────────────────
        story.append(Paragraph("Pengesahan Laporan", styles["section"]))
        story.append(Spacer(1, 5 * mm))

        sig_data = [
            [f"Telah Dilaksanakan Oleh:\nGhost Shopper", "Disetujui Oleh:\nKoordinator GS / PIC Outlet"],
            ["", ""],  # Empty row for signature image placeholder
            [f"( {visit.ghost_shopper or '................................'} )", "( ................................ )"]
        ]
        sig_table = Table(sig_data, colWidths=[85*mm, 85*mm])
        sig_table.setStyle(TableStyle([
            ("ALIGN", (0,0), (-1,-1), "CENTER"),
            ("VALIGN", (0,0), (-1,-1), "BOTTOM"),
            ("FONTNAME", (0,0), (-1,0), "Helvetica-Bold"),
            ("FONTSIZE", (0,0), (-1,0), 9),
            ("FONTSIZE", (0,2), (-1,2), 10),
            ("ROWBACKGROUNDS", (0, 0), (-1, -1), [colors.white]),
            ("BOTTOMPADDING", (0, 1), (-1, 1), 30),  # Tall row for signature box
        ]))
        story.append(sig_table)

        # ── Footer ────────────────────────────────────────────
        story.append(Spacer(1, 10 * mm))
        story.append(HRFlowable(width="100%", thickness=0.5, color=GREY_TEXT))
        story.append(Paragraph(
            f"Apl_GS — Laporan Kunjungan  •  {visit.title}  •  "
            f"Dicetak {datetime.utcnow().strftime('%d %b %Y')}",
            ParagraphStyle(
                "Footer", parent=getSampleStyleSheet()["Normal"],
                fontSize=7, textColor=GREY_TEXT, alignment=TA_CENTER,
            ),
        ))

        doc.build(story)
        pdf_bytes = buffer.getvalue()
        buffer.close()

        logger.info(
            f"PDF generated for visit {visit_id} — {len(pdf_bytes)} bytes"
        )
        return pdf_bytes


# Singleton
pdf_service = PDFService()