import { PDFDocument, StandardFonts, rgb } from 'pdf-lib';
import path from 'path';
import fs from 'fs';

const MONTANT_MOYEN = 6.8;

// ─── Palette ───────────────────────────────────────────────
const TEAL = { r: 43 / 255, g: 147 / 255, b: 157 / 255 };
const DARK = { r: 0.2, g: 0.2, b: 0.2 };
const MID = { r: 0.5, g: 0.5, b: 0.5 };
const LINE = { r: 0.82, g: 0.82, b: 0.82 };
const LIGHT_BG = { r: 0.96, g: 0.96, b: 0.96 };
const TEAL_BG = { r: 235 / 255, g: 248 / 255, b: 249 / 255 };

export interface ParticipationData {
  adherentNom: string;
  adherentPrenom: string;
  adherentAdresse: string;
  destinataireEmail: string;
  destinataireNom: string;
  dateTrajet: Date;
  adresseDepart: string;
  adresseArrivee: string;
  montant?: number;
  complement?: string;
  participationId?: string;
}

// ─── Helpers ───────────────────────────────────────────────

async function loadLogoAsPng(logoName: string, maxSize: number): Promise<Buffer | null> {
  try {
    const sharp = (await import('sharp')).default;
    const logoPath = path.join(process.cwd(), 'public', logoName);
    if (!fs.existsSync(logoPath)) return null;
    return sharp(logoPath)
      .resize(maxSize, maxSize, { fit: 'inside' })
      .png()
      .toBuffer();
  } catch {
    return null;
  }
}

function wrapText(text: string, maxWidth: number, measureFn: (t: string) => number): string[] {
  const words = text.split(/\s+/);
  const lines: string[] = [];
  let currentLine = '';
  for (const word of words) {
    const testLine = currentLine ? `${currentLine} ${word}` : word;
    if (measureFn(testLine) <= maxWidth) {
      currentLine = testLine;
    } else {
      if (currentLine) lines.push(currentLine);
      currentLine = word;
    }
  }
  if (currentLine) lines.push(currentLine);
  return lines;
}

// ─── Génération du PDF ─────────────────────────────────────

export async function generateParticipationPDF(
  data: ParticipationData,
  outputPath: string
): Promise<Buffer> {
  const pdfDoc = await PDFDocument.create();
  const font = await pdfDoc.embedFont(StandardFonts.Helvetica);
  const fontBold = await pdfDoc.embedFont(StandardFonts.HelveticaBold);
  const page = pdfDoc.addPage([595, 842]); // A4
  const { width } = page.getSize();

  const M = 50;               // marge
  const R = width - M;        // bord droit (545)
  const CW = width - 2 * M;   // largeur utile (495)

  const teal = rgb(TEAL.r, TEAL.g, TEAL.b);
  const dark = rgb(DARK.r, DARK.g, DARK.b);
  const mid = rgb(MID.r, MID.g, MID.b);

  // Raccourcis
  const measure = (text: string, size: number, f = font) => f.widthOfTextAtSize(text, size);

  const drawRight = (
    text: string, x: number, y: number, size: number,
    f = font, color = dark
  ) => {
    page.drawText(text, { x: x - f.widthOfTextAtSize(text, size), y, size, font: f, color });
  };

  const hLine = (y: number, x = M, w = CW) => {
    page.drawRectangle({
      x, y, width: w, height: 1,
      color: rgb(LINE.r, LINE.g, LINE.b),
    });
  };

  // Données formatées
  const montant = data.montant ?? MONTANT_MOYEN;
  const montantStr = montant.toFixed(2).replace('.', ',') + ' \u20AC';
  const refNum = data.participationId
    ? `PART-${data.participationId.slice(-8).toUpperCase()}`
    : 'PART-XXXXXXXX';
  const dateEmission = data.dateTrajet.toLocaleDateString('fr-FR', {
    day: '2-digit', month: '2-digit', year: 'numeric',
  });
  const dateTrajetLong = data.dateTrajet.toLocaleDateString('fr-FR', {
    weekday: 'long', day: '2-digit', month: 'long', year: 'numeric',
  });

  let y = 800;

  // ════════════════════════════════════════════════════════
  //  EN-TÊTE
  // ════════════════════════════════════════════════════════

  // Logo
  const logoPng = await loadLogoAsPng('logo.svg', 48);
  const logoS = 48;
  if (logoPng) {
    try {
      const img = await pdfDoc.embedPng(logoPng);
      const w = img.width * (logoS / img.height);
      page.drawImage(img, {
        x: M, y: y - logoS,
        width: Math.min(w, logoS), height: logoS,
      });
    } catch { /* fallback silencieux */ }
  }

  // Infos association (à droite du logo)
  const hx = M + logoS + 14;
  page.drawText('Association MAD', {
    x: hx, y: y - 15, size: 13, font: fontBold, color: teal,
  });
  page.drawText('Adresse postale', {
    x: hx, y: y - 29, size: 9, font, color: mid,
  });
  page.drawText('Ville, Code postal', {
    x: hx, y: y - 41, size: 9, font, color: mid,
  });

  // Référence document (aligné à droite)
  drawRight('Participation financière', R, y - 12, 9, font, mid);
  drawRight(refNum, R, y - 28, 11, fontBold, teal);
  drawRight(`\u00C9mise le ${dateEmission}`, R, y - 44, 9, font, mid);

  // Séparateur
  y -= 62;
  hLine(y);

  // ════════════════════════════════════════════════════════
  //  TITRE
  // ════════════════════════════════════════════════════════

  y -= 30;
  page.drawText('Participation financière au transport', {
    x: M, y, size: 17, font: fontBold, color: teal,
  });
  y -= 16;
  page.drawText(
    "Document établi dans le cadre de l'accompagnement au transport par l'Association MAD.",
    { x: M, y, size: 9, font, color: mid },
  );

  // ════════════════════════════════════════════════════════
  //  BLOCS D'INFORMATION
  // ════════════════════════════════════════════════════════

  y -= 56;
  const gap = 24;
  const bw = (CW - gap) / 2;   // ~235px par bloc
  const bx2 = M + bw + gap;    // x du bloc droit

  // Helper : titre de section avec soulignement teal
  const sectionTitle = (label: string, x: number, yy: number) => {
    page.drawText(label, { x, y: yy, size: 8, font: fontBold, color: teal });
    page.drawRectangle({
      x, y: yy - 3,
      width: fontBold.widthOfTextAtSize(label, 8), height: 1.5,
      color: teal,
    });
  };

  // ── Bloc gauche : FACTURÉ À ──
  const blockTopY = y;
  sectionTitle('FACTURÉ À', M, blockTopY);

  let ly = blockTopY - 20;
  const destLines = wrapText(data.destinataireNom, bw, (t) => measure(t, 10, fontBold));
  for (const line of destLines.slice(0, 2)) {
    page.drawText(line, { x: M, y: ly, size: 10, font: fontBold, color: dark });
    ly -= 14;
  }
  page.drawText(data.destinataireEmail, {
    x: M, y: ly, size: 9, font, color: mid,
  });
  ly -= 14;

  // ── Bloc droit : DÉTAILS DU TRAJET ──
  sectionTitle('DÉTAILS DU TRAJET', bx2, blockTopY);

  let ry = blockTopY - 20;
  const infos: { label: string; value: string }[] = [
    { label: 'Date', value: dateTrajetLong },
    { label: 'Adhérent', value: `${data.adherentPrenom} ${data.adherentNom}` },
  ];

  for (const item of infos) {
    const prefix = `${item.label} : `;
    const prefixW = measure(prefix, 8, fontBold);

    page.drawText(prefix, {
      x: bx2, y: ry, size: 8, font: fontBold, color: dark,
    });

    const valLines = wrapText(item.value, bw - prefixW, (t) => measure(t, 9));
    for (let i = 0; i < Math.min(valLines.length, 2); i++) {
      page.drawText(valLines[i], {
        x: bx2 + prefixW, y: ry, size: 9, font, color: dark,
      });
      if (i < valLines.length - 1) ry -= 12;
    }
    ry -= 16;
  }

  // ════════════════════════════════════════════════════════
  //  TABLEAU
  // ════════════════════════════════════════════════════════

  y = Math.min(ly, ry) - 56;

  // Positions des colonnes
  const cDesig = M + 10;
  const cQte = M + 290;
  const cPu = M + 370;
  // cMontant : aligné à droite sur R - 8

  // ── En-tête du tableau ──
  const thH = 28;

  // Ligne d'accent teal en haut
  page.drawRectangle({
    x: M, y: y + thH - 2, width: CW, height: 2, color: teal,
  });

  // Fond gris clair
  page.drawRectangle({
    x: M, y: y, width: CW, height: thH - 2,
    color: rgb(LIGHT_BG.r, LIGHT_BG.g, LIGHT_BG.b),
  });

  const thY = y + 8;
  page.drawText('DÉSIGNATION', {
    x: cDesig, y: thY, size: 8, font: fontBold, color: dark,
  });
  // QTÉ centré
  const qteLabel = 'QTÉ';
  const qteLabelW = measure(qteLabel, 8, fontBold);
  page.drawText(qteLabel, {
    x: cQte + 20 - qteLabelW / 2, y: thY, size: 8, font: fontBold, color: dark,
  });
  page.drawText('P.U.', {
    x: cPu, y: thY, size: 8, font: fontBold, color: dark,
  });
  drawRight('MONTANT', R - 8, thY, 8, fontBold, dark);

  // Ligne sous en-tête
  hLine(y);

  // ── Ligne article ──
  y -= 18;
  const articleTitleY = y;

  // Titre de l'article
  page.drawText('Participation au transport', {
    x: cDesig, y: articleTitleY, size: 10, font: fontBold, color: dark,
  });

  // Adresses complètes (wrappées, sans troncature)
  const maxDesigW = cQte - cDesig - 20;

  const depLines = wrapText(
    `De : ${data.adresseDepart}`, maxDesigW, (t) => measure(t, 8),
  );
  const arrLines = wrapText(
    `Vers : ${data.adresseArrivee}`, maxDesigW, (t) => measure(t, 8),
  );

  let addrY = articleTitleY - 16;
  for (const line of depLines.slice(0, 3)) {
    page.drawText(line, { x: cDesig, y: addrY, size: 8, font, color: mid });
    addrY -= 11;
  }
  addrY -= 2; // petit espace entre départ et arrivée
  for (const line of arrLines.slice(0, 3)) {
    page.drawText(line, { x: cDesig, y: addrY, size: 8, font, color: mid });
    addrY -= 11;
  }

  // Valeurs numériques (centrées verticalement avec le titre)
  const numY = articleTitleY - 6;
  // QTÉ centré
  const qteVal = '1';
  const qteValW = measure(qteVal, 10);
  page.drawText(qteVal, {
    x: cQte + 20 - qteValW / 2, y: numY, size: 10, font, color: dark,
  });
  page.drawText(montantStr, {
    x: cPu, y: numY, size: 10, font, color: dark,
  });
  drawRight(montantStr, R - 8, numY, 10, fontBold, dark);

  // Ligne de fin d'article
  const rowBottom = Math.min(addrY, numY - 16) - 6;
  hLine(rowBottom);

  // ════════════════════════════════════════════════════════
  //  TOTAUX
  // ════════════════════════════════════════════════════════

  y = rowBottom - 20;
  const tLabelX = R - 160;
  const tValX = R - 8;

  // Sous-total
  page.drawText('Sous-total', {
    x: tLabelX, y, size: 10, font, color: dark,
  });
  drawRight(montantStr, tValX, y, 10, font, dark);

  // Séparateur
  y -= 20;
  hLine(y + 8, tLabelX, R - tLabelX);

  // Total dû (surligné)
  y -= 4;
  page.drawRectangle({
    x: tLabelX - 10, y: y - 6,
    width: R - tLabelX + 18, height: 26,
    color: rgb(TEAL_BG.r, TEAL_BG.g, TEAL_BG.b),
  });
  page.drawText('Total dû', {
    x: tLabelX, y: y + 2, size: 13, font: fontBold, color: teal,
  });
  drawRight(montantStr, tValX, y + 2, 13, fontBold, teal);

  // Échéance
  y -= 32;
  page.drawText(`Échéance de paiement : ${dateEmission}`, {
    x: tLabelX, y, size: 8, font, color: mid,
  });

  // ════════════════════════════════════════════════════════
  //  COMPLÉMENT (optionnel)
  // ════════════════════════════════════════════════════════

  if (data.complement) {
    y -= 34;
    page.drawText('Note :', {
      x: M, y, size: 9, font: fontBold, color: dark,
    });
    y -= 14;
    const compLines = wrapText(data.complement, CW - 20, (t) => measure(t, 9));
    for (const line of compLines.slice(0, 4)) {
      page.drawText(line, { x: M, y, size: 9, font, color: dark });
      y -= 13;
    }
  }

  // ════════════════════════════════════════════════════════
  //  PIED DE PAGE
  // ════════════════════════════════════════════════════════

  const footerY = 55;
  page.drawRectangle({
    x: 0, y: 0, width, height: footerY + 2,
    color: rgb(0.98, 0.98, 0.98),
  });
  hLine(footerY);

  page.drawText(
    'Ce document fait office de participation financière au transport. Établi par Association MAD.',
    { x: M, y: 35, size: 8, font, color: mid },
  );

  // Propulsé par LGX + logo
  const propText = 'Propulsé par LGX';
  const lgxLogoPng = await loadLogoAsPng('lgx-logo.svg', 28);

  if (lgxLogoPng) {
    try {
      const lgxImg = await pdfDoc.embedPng(lgxLogoPng);
      const lgxH = 16;
      const lgxW = lgxImg.width * (lgxH / lgxImg.height);
      const blockW = fontBold.widthOfTextAtSize(propText, 9) + lgxW + 8;
      const lgxX = R - blockW;
      page.drawText(propText, {
        x: lgxX, y: 35, size: 9, font: fontBold, color: mid,
      });
      page.drawImage(lgxImg, {
        x: lgxX + fontBold.widthOfTextAtSize(propText, 9) + 6,
        y: 29, width: lgxW, height: lgxH,
      });
    } catch {
      page.drawText(propText, {
        x: R - fontBold.widthOfTextAtSize(propText, 9),
        y: 35, size: 9, font: fontBold, color: teal,
      });
    }
  } else {
    page.drawText(propText, {
      x: R - fontBold.widthOfTextAtSize(propText, 9),
      y: 35, size: 9, font: fontBold, color: teal,
    });
  }

  // ════════════════════════════════════════════════════════
  //  SAUVEGARDE
  // ════════════════════════════════════════════════════════

  const pdfBytes = await pdfDoc.save();
  const dir = path.dirname(outputPath);
  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
  fs.writeFileSync(outputPath, pdfBytes);
  return Buffer.from(pdfBytes);
}

export function getParticipationStoragePath(participationId: string): string {
  return path.join(process.cwd(), 'data', 'participations', `${participationId}.pdf`);
}