# -----------------------------------------------------------------------------
# Auto-Ka — Agrégateur de voitures usagées à vendre (province de Québec)
# Auteur : Simon-Pierre Boucher — contact@spboucher.ai
# pdfgen.py : rapport PDF « Le marché de l'occasion » — vue d'ensemble des
#             statistiques (héros, distributions, marques, régions, aubaines).
# -----------------------------------------------------------------------------
from __future__ import annotations

import datetime
import io

from reportlab.lib.colors import HexColor
from reportlab.lib.pagesizes import letter
from reportlab.lib.units import mm
from reportlab.pdfgen.canvas import Canvas

from . import marketstats

INK = HexColor("#17181c")
INK2 = HexColor("#4c4f57")
INK3 = HexColor("#8b8e96")
ACCENT = HexColor("#ff5a2a")
ACCENT_DEEP = HexColor("#cc3f16")
PAPER = HexColor("#f4f2ec")
SURFACE = HexColor("#ffffff")
GOOD = HexColor("#1c7a4d")
LINE = HexColor("#d8d5cd")

W, H = letter
MARGIN = 18 * mm


def _fmt(n, suffix="") -> str:
    if n is None:
        return "—"
    return f"{round(n):,}".replace(",", " ") + suffix


class _Doc:
    """Petit assistant de mise en page (curseur vertical + gabarits)."""

    def __init__(self, canvas: Canvas):
        self.c = canvas
        self.y = H - MARGIN
        self.page = 1
        self._chrome()

    # -- gabarit de page -------------------------------------------------------
    def _chrome(self):
        c = self.c
        c.setFillColor(PAPER)
        c.rect(0, 0, W, H, stroke=0, fill=1)
        # bandeau encre
        c.setFillColor(INK)
        c.rect(0, H - 12 * mm, W, 12 * mm, stroke=0, fill=1)
        c.setFillColor(ACCENT)
        c.setFont("Helvetica-Bold", 11)
        c.drawString(MARGIN, H - 8 * mm, "Auto·Ka")
        c.setFillColor(HexColor("#c9cbd1"))
        c.setFont("Helvetica", 8)
        c.drawString(MARGIN + 18 * mm, H - 8 * mm,
                     "Le marché des voitures usagées au Québec — rapport d'ensemble")
        c.drawRightString(W - MARGIN, H - 8 * mm,
                          datetime.date.today().strftime("%Y-%m-%d"))
        # pied
        c.setFillColor(INK3)
        c.setFont("Helvetica", 7)
        c.drawString(MARGIN, 10 * mm,
                     "www.auto-ka.com — agrégateur indépendant, données lues "
                     "directement sur les sites des concessionnaires")
        c.drawRightString(W - MARGIN, 10 * mm, f"page {self.page}")
        self.y = H - 22 * mm

    def new_page(self):
        self.c.showPage()
        self.page += 1
        self._chrome()

    def need(self, height: float):
        if self.y - height < 16 * mm:
            self.new_page()

    # -- blocs -----------------------------------------------------------------
    def title(self, text: str):
        self.need(14 * mm)
        self.c.setFillColor(ACCENT_DEEP)
        self.c.setFont("Helvetica-Bold", 8)
        self.c.drawString(MARGIN, self.y, "—  " + text.upper())
        self.y -= 7 * mm

    def hero_row(self, items: list[tuple[str, str]]):
        """Rangée de tuiles héros (valeur + étiquette)."""
        n = len(items)
        gap = 4 * mm
        w = (W - 2 * MARGIN - gap * (n - 1)) / n
        h = 20 * mm
        self.need(h + 6 * mm)
        x = MARGIN
        for value, label in items:
            self.c.setFillColor(SURFACE)
            self.c.setStrokeColor(INK)
            self.c.setLineWidth(1.2)
            self.c.roundRect(x, self.y - h, w, h, 2 * mm, stroke=1, fill=1)
            self.c.setFillColor(INK)
            self.c.setFont("Helvetica-Bold", 15)
            self.c.drawString(x + 3.5 * mm, self.y - 9 * mm, value)
            self.c.setFillColor(INK3)
            self.c.setFont("Helvetica", 6.5)
            self.c.drawString(x + 3.5 * mm, self.y - h + 3.5 * mm, label.upper())
            x += w + gap
        self.y -= h + 8 * mm

    def bars(self, rows: list[dict], value_key="n", label_key="label",
             extra_key=None, height_per=6.2 * mm, color=ACCENT,
             value_fmt=lambda v: _fmt(v)):
        """Barres horizontales fines, étiquettes directes, coins arrondis."""
        if not rows:
            return
        total_h = height_per * len(rows)
        self.need(total_h + 4 * mm)
        max_v = max(r[value_key] or 0 for r in rows) or 1
        label_w = 42 * mm
        bar_max = W - 2 * MARGIN - label_w - 26 * mm
        for r in rows:
            v = r[value_key] or 0
            bw = max(1.2 * mm, bar_max * v / max_v)
            yb = self.y - 4.2 * mm
            self.c.setFillColor(INK2)
            self.c.setFont("Helvetica", 7.5)
            label = str(r[label_key])[:30]
            self.c.drawRightString(MARGIN + label_w - 2 * mm, yb + 0.6 * mm, label)
            self.c.setFillColor(color)
            self.c.roundRect(MARGIN + label_w, yb, bw, 3.4 * mm, 1 * mm,
                             stroke=0, fill=1)
            self.c.setFillColor(INK)
            self.c.setFont("Helvetica-Bold", 7)
            txt = value_fmt(v)
            if extra_key and r.get(extra_key) is not None:
                txt += f"   ·  moy. {_fmt(r[extra_key], ' $')}"
                self.c.setFont("Helvetica", 7)
            self.c.drawString(MARGIN + label_w + bw + 2 * mm, yb + 0.6 * mm, txt)
            self.y -= height_per
        self.y -= 5 * mm

    def histogram(self, rows: list[dict], height=32 * mm, color=ACCENT):
        """Histogramme vertical (classes de prix/km/années)."""
        if not rows:
            return
        self.need(height + 14 * mm)
        n = len(rows)
        gap = 1.6 * mm
        bw = (W - 2 * MARGIN - gap * (n - 1)) / n
        max_v = max(r["n"] for r in rows) or 1
        base = self.y - height
        x = MARGIN
        self.c.setFont("Helvetica", 6)
        for r in rows:
            bh = max(1 * mm, height * r["n"] / max_v)
            self.c.setFillColor(color)
            self.c.roundRect(x, base, bw, bh, 1 * mm, stroke=0, fill=1)
            self.c.setFillColor(INK)
            self.c.setFont("Helvetica-Bold", 6)
            self.c.drawCentredString(x + bw / 2, base + bh + 1.4 * mm, _fmt(r["n"]))
            self.c.setFillColor(INK3)
            self.c.setFont("Helvetica", 5.8)
            self.c.drawCentredString(x + bw / 2, base - 3.2 * mm, r["label"])
            x += bw + gap
        self.y = base - 9 * mm

    def table(self, headers: list[str], rows: list[list[str]],
              widths: list[float]):
        self.need(6 * mm * (len(rows) + 1))
        x = MARGIN
        self.c.setFont("Helvetica-Bold", 7)
        self.c.setFillColor(INK3)
        for htxt, w in zip(headers, widths):
            self.c.drawString(x, self.y, htxt.upper())
            x += w
        self.y -= 1.6 * mm
        self.c.setStrokeColor(INK)
        self.c.setLineWidth(0.8)
        self.c.line(MARGIN, self.y, W - MARGIN, self.y)
        self.y -= 4.4 * mm
        for row in rows:
            self.need(5.4 * mm)
            x = MARGIN
            self.c.setFont("Helvetica", 7.5)
            self.c.setFillColor(INK)
            for cell, w in zip(row, widths):
                self.c.drawString(x, self.y, str(cell)[:42])
                x += w
            self.c.setStrokeColor(LINE)
            self.c.setLineWidth(0.4)
            self.c.line(MARGIN, self.y - 1.6 * mm, W - MARGIN, self.y - 1.6 * mm)
            self.y -= 5.4 * mm
        self.y -= 4 * mm


def rapport_pdf() -> bytes:
    """Rapport PDF multi-pages : vue d'ensemble du marché de l'occasion."""
    s = marketstats.compute()
    buf = io.BytesIO()
    c = Canvas(buf, pagesize=letter)
    c.setTitle("Auto-Ka — Rapport du marché de l'occasion")
    c.setAuthor("Simon-Pierre Boucher — contact@spboucher.ai")
    doc = _Doc(c)

    # -- entête / héros ---------------------------------------------------------
    doc.c.setFillColor(INK)
    doc.c.setFont("Helvetica-Bold", 22)
    doc.c.drawString(MARGIN, doc.y, "Le marché de l'occasion, en un coup d'œil")
    doc.y -= 6 * mm
    doc.c.setFillColor(INK2)
    doc.c.setFont("Helvetica", 9)
    doc.c.drawString(
        MARGIN, doc.y,
        f"Inventaire actif agrégé de {s['sources']} concessionnaires dans "
        f"{s['regions']} régions du Québec.")
    doc.y -= 10 * mm

    doc.hero_row([
        (_fmt(s["total"]), "véhicules en vente"),
        (_fmt(s["avg_price"], " $"), "prix moyen"),
        (_fmt(s["median_price"], " $"), "prix médian"),
        (_fmt(s["avg_km"], " km"), "km moyen"),
    ])
    doc.hero_row([
        (f"{s['avg_year']:.0f}" if s["avg_year"] else "—", "année moyenne"),
        (_fmt(s["new_7d"]), "arrivages (7 jours)"),
        (f"{s['electrified_pct']} %", "électrifiés (VÉ + hybrides)"),
        (_fmt(s["sources"]), "concessionnaires"),
    ])

    # -- distributions ----------------------------------------------------------
    doc.title("Distribution des prix")
    doc.histogram(s["price_hist"])
    doc.title("Distribution du kilométrage (milliers de km)")
    doc.histogram(s["km_hist"], color=HexColor("#1f6fb5"))

    # -- marques / régions ------------------------------------------------------
    doc.new_page()
    doc.title("Top marques (inventaire et prix moyen)")
    doc.bars(s["by_make"], extra_key="avg_price")
    doc.title("Par région (inventaire et prix moyen)")
    doc.bars(s["by_region"], extra_key="avg_price",
             color=HexColor("#1f6fb5"))

    # -- modèles ----------------------------------------------------------------
    doc.new_page()
    doc.title("Modèles les plus offerts")
    doc.table(
        ["Modèle", "En vente", "Prix moyen", "KM moyen"],
        [[r["label"], _fmt(r["n"]), _fmt(r["avg_price"], " $"),
          _fmt(r["avg_km"], " km")] for r in s["top_models"]],
        [70 * mm, 30 * mm, 38 * mm, 38 * mm])

    doc.title("Carrosseries")
    doc.bars(s["by_body"], color=HexColor("#1c7a4d"))
    doc.title("Carburants")
    doc.bars(s["by_fuel"], color=HexColor("#b58500"))

    # -- aubaines ---------------------------------------------------------------
    if s["price_drops"]:
        doc.new_page()
        doc.title("Baisses de prix récentes (aubaines détectées)")
        doc.table(
            ["Véhicule", "Avant", "Maintenant", "Économie", "Concessionnaire"],
            [[f"{r['title'][:34]}", _fmt(r["prev_price"], " $"),
              _fmt(r["price"], " $"),
              "-" + _fmt(r["prev_price"] - r["price"], " $"),
              f"{r['dealer_name'][:22]} ({r['city']})"]
             for r in s["price_drops"]],
            [62 * mm, 24 * mm, 26 * mm, 24 * mm, 44 * mm])

    doc.title("Plus grands inventaires")
    doc.bars(s["top_dealers"], extra_key="avg_price",
             color=HexColor("#7d4fc9"))

    c.save()
    return buf.getvalue()