/**
 * Génération PDF Ventilation FreePro côté serveur avec pdf-lib.
 * Garantit 1 page A4 portrait quelle que soit la taille des données.
 */
import { PDFDocument, rgb, StandardFonts } from "pdf-lib";

interface PdfLine {
  structure: string;
  type: string;
  montantCentimes: number;
}

interface PdfImportInfo {
  mois: string; // ex: "01/2025"
  refPiece: string;
}

function formatMontant(centimes: number): string {
  const euros = centimes / 100;
  const neg = euros < 0;
  const abs = Math.abs(euros);
  const str = abs.toFixed(2).replace(".", ",");
  const parts = str.split(",");
  parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, " ");
  return (neg ? "-" : "") + parts.join(",") + " EUR";
}

export async function generateFreeproPdf(
  info: PdfImportInfo,
  lines: PdfLine[]
): Promise<Uint8Array> {
  const pdfDoc = await PDFDocument.create();
  const page = pdfDoc.addPage([595.28, 841.89]); // A4 portrait en points (72dpi)

  const helvetica = await pdfDoc.embedFont(StandardFonts.Helvetica);
  const helveticaBold = await pdfDoc.embedFont(StandardFonts.HelveticaBold);

  const { width, height } = page.getSize();
  const marginX = 40;
  const tableStartY = height - 90; // Y depuis le bas (pdf-lib: 0=bas)
  const tableEndY = 28;
  const usableW = width - marginX * 2;

  // Colonnes
  const col0W = usableW * 0.45;
  const col1W = usableW * 0.32;
  const col2W = usableW * 0.23;
  const col1X = marginX + col0W;
  const col2X = col1X + col1W;

  // Calcul hauteur de ligne
  const nbRows = lines.length + 2; // header + data + footer
  const availH = tableStartY - tableEndY;
  const rowH = availH / nbRows;
  const fontSize = Math.max(5, Math.min(9, rowH * 0.55));

  // ── En-tête du document ──────────────────────────────────────────────────
  const now = new Date();
  // Date édition (haut droite)
  page.drawText(
    `Edite le ${now.toLocaleDateString("fr-FR")} - ${now.toLocaleTimeString("fr-FR", { hour: "2-digit", minute: "2-digit" })}`,
    {
      x: width - marginX - 120,
      y: height - 20,
      size: 7,
      font: helvetica,
      color: rgb(0.4, 0.4, 0.4),
    }
  );

  // Titre
  const title = "Ventilation facture FREE PRO";
  const titleW = helveticaBold.widthOfTextAtSize(title, 14);
  page.drawText(title, {
    x: (width - titleW) / 2,
    y: height - 38,
    size: 14,
    font: helveticaBold,
    color: rgb(0, 0, 0),
  });

  // Mois
  const moisLabel = info.mois
    ? (() => {
        const [mm, yyyy] = info.mois.split("/");
        const d = new Date(parseInt(yyyy), parseInt(mm) - 1, 1);
        return `${String(d.getMonth() + 1).padStart(2, "0")}/${d.getFullYear()}`;
      })()
    : info.mois;
  const moisW = helveticaBold.widthOfTextAtSize(moisLabel, 11);
  page.drawText(moisLabel, {
    x: (width - moisW) / 2,
    y: height - 56,
    size: 11,
    font: helveticaBold,
    color: rgb(0, 0, 0),
  });

  // Ref pièce
  page.drawText("ref_piece :", {
    x: marginX,
    y: height - 74,
    size: 8,
    font: helveticaBold,
    color: rgb(0, 0, 0),
  });
  page.drawText(info.refPiece || "", {
    x: marginX + 60,
    y: height - 74,
    size: 8,
    font: helvetica,
    color: rgb(0, 0, 0),
  });

  // ── Helpers de dessin ────────────────────────────────────────────────────
  const drawHLine = (yFromTop: number, lw: number, gray: number) => {
    const y = height - yFromTop;
    page.drawLine({
      start: { x: marginX, y },
      end: { x: marginX + usableW, y },
      thickness: lw,
      color: rgb(gray, gray, gray),
    });
  };

  const drawVLines = (yFromTop: number, h: number) => {
    const y = height - yFromTop;
    const xs = [marginX, col1X, col2X, marginX + usableW];
    for (const x of xs) {
      page.drawLine({
        start: { x, y },
        end: { x, y: y - h },
        thickness: 0.3,
        color: rgb(0.7, 0.7, 0.7),
      });
    }
  };

  const drawRowBg = (yFromTop: number, bgGray: number) => {
    page.drawRectangle({
      x: marginX,
      y: height - yFromTop - rowH,
      width: usableW,
      height: rowH,
      color: rgb(bgGray, bgGray, bgGray),
    });
  };

  const drawCell = (
    text: string,
    xLeft: number,
    xRight: number,
    yFromTop: number,
    bold: boolean,
    align: "left" | "right" = "left"
  ) => {
    const font = bold ? helveticaBold : helvetica;
    const maxW = xRight - xLeft - 4;
    // Tronquer si trop long
    let t = text;
    while (t.length > 1 && font.widthOfTextAtSize(t, fontSize) > maxW) {
      t = t.slice(0, -1);
    }
    const tw = font.widthOfTextAtSize(t, fontSize);
    const x = align === "right" ? xRight - tw - 2 : xLeft + 2;
    const y = height - yFromTop - rowH * 0.65;
    page.drawText(t, { x, y, size: fontSize, font, color: rgb(0, 0, 0) });
  };

  // ── Header du tableau ────────────────────────────────────────────────────
  const headerYFromTop = height - tableStartY; // converti en "depuis le haut"
  // On travaille directement en coordonnées "depuis le haut" pour la logique
  // puis on convertit pour pdf-lib

  // Recalcul en coordonnées "depuis le haut de la page" pour la logique
  const tStartFromTop = height - tableStartY; // pixels depuis le haut = height - y_pdflib

  // En fait, simplifions : on calcule tout en "Y depuis le haut de la page"
  // et on convertit à la fin pour pdf-lib (y_pdflib = height - y_fromtop)

  // Redéfinir les helpers avec "yT" = Y depuis le haut
  const hLine = (yT: number, lw: number, gray: number) => {
    page.drawLine({
      start: { x: marginX, y: height - yT },
      end: { x: marginX + usableW, y: height - yT },
      thickness: lw,
      color: rgb(gray, gray, gray),
    });
  };

  const vLines = (yT: number, h: number) => {
    for (const x of [marginX, col1X, col2X, marginX + usableW]) {
      page.drawLine({
        start: { x, y: height - yT },
        end: { x, y: height - yT - h },
        thickness: 0.3,
        color: rgb(0.7, 0.7, 0.7),
      });
    }
  };

  const rowBg = (yT: number, gray: number) => {
    page.drawRectangle({
      x: marginX,
      y: height - yT - rowH,
      width: usableW,
      height: rowH,
      color: rgb(gray, gray, gray),
    });
  };

  const cell = (
    text: string,
    xL: number,
    xR: number,
    yT: number,
    bold: boolean,
    align: "left" | "right" = "left"
  ) => {
    const font = bold ? helveticaBold : helvetica;
    const maxW = xR - xL - 4;
    let t = text;
    while (t.length > 1 && font.widthOfTextAtSize(t, fontSize) > maxW) {
      t = t.slice(0, -1);
    }
    const tw = font.widthOfTextAtSize(t, fontSize);
    const x = align === "right" ? xR - tw - 2 : xL + 2;
    const y = height - yT - rowH * 0.65;
    page.drawText(t, { x, y, size: fontSize, font, color: rgb(0, 0, 0) });
  };

  // Tableau commence à yT = 90 (depuis le haut)
  const tableTopYT = 90;

  // Header
  rowBg(tableTopYT, 0.88);
  hLine(tableTopYT, 0.5, 0);
  cell("Structure", marginX, col1X, tableTopYT, true);
  cell("Type", col1X, col2X, tableTopYT, true);
  cell("Montant TTC", col2X, marginX + usableW, tableTopYT, true, "right");
  hLine(tableTopYT + rowH, 0.5, 0);
  vLines(tableTopYT, rowH);

  // Lignes de données
  for (let i = 0; i < lines.length; i++) {
    const l = lines[i];
    const yT = tableTopYT + rowH * (i + 1);
    if (i % 2 === 1) rowBg(yT, 0.97);
    cell(l.structure || "", marginX, col1X, yT, false);
    cell(l.type || "", col1X, col2X, yT, false);
    cell(formatMontant(l.montantCentimes), col2X, marginX + usableW, yT, false, "right");
    hLine(yT + rowH, 0.2, 0.78);
    vLines(yT, rowH);
  }

  // Footer total
  const totalCentimes = lines.reduce((s, l) => s + l.montantCentimes, 0);
  const footerYT = tableTopYT + rowH * (lines.length + 1);
  rowBg(footerYT, 0.88);
  hLine(footerYT, 0.5, 0);
  cell("Total general", marginX, col1X, footerYT, true);
  cell(formatMontant(totalCentimes), col2X, marginX + usableW, footerYT, true, "right");
  hLine(footerYT + rowH, 0.5, 0);
  vLines(footerYT, rowH);

  return pdfDoc.save();
}