/**
 * Shared PDF helpers for statements and reports.
 *
 * Uses pdf-lib to compose A4 PDFs in Node (Edge-compatible).
 */

import { PDFDocument, StandardFonts, rgb, type PDFFont, type PDFPage } from "pdf-lib";

export const COMPANY = {
  name: "RJ Bulk Supplies",
  tagline: "Fuel delivery specialists",
  address: "Gauteng, South Africa",
  email: "accounts@rjbulk.co.za",
  vat: "4023456789",
};

export interface PDFContext {
  doc: PDFDocument;
  page: PDFPage;
  font: PDFFont;
  fontBold: PDFFont;
  y: number;
}

export async function newPDF(): Promise<PDFContext> {
  const doc = await PDFDocument.create();
  doc.setTitle(COMPANY.name);
  doc.setAuthor(COMPANY.name);
  const font = await doc.embedFont(StandardFonts.Helvetica);
  const fontBold = await doc.embedFont(StandardFonts.HelveticaBold);
  const page = doc.addPage([595, 842]); // A4
  return { doc, page, font, fontBold, y: 800 };
}

export function addPage(ctx: PDFContext): void {
  ctx.page = ctx.doc.addPage([595, 842]);
  ctx.y = 800;
}

export const COLORS = {
  primary: rgb(0.85, 0.45, 0.18), // matches orange theme
  text: rgb(0.13, 0.16, 0.22),
  muted: rgb(0.5, 0.55, 0.6),
  border: rgb(0.85, 0.88, 0.9),
  bgAlt: rgb(0.97, 0.98, 0.98),
};

export function drawHeader(ctx: PDFContext, title: string, subtitle?: string): void {
  const { page, font, fontBold } = ctx;
  // Brand block
  page.drawRectangle({ x: 40, y: 780, width: 60, height: 30, color: COLORS.primary });
  page.drawText("RJ", { x: 55, y: 790, size: 18, font: fontBold, color: rgb(1, 1, 1) });
  page.drawText(COMPANY.name, { x: 110, y: 793, size: 14, font: fontBold, color: COLORS.text });
  page.drawText(COMPANY.tagline, { x: 110, y: 781, size: 8, font, color: COLORS.muted });

  // Title (right)
  const titleSize = 16;
  const titleW = fontBold.widthOfTextAtSize(title, titleSize);
  page.drawText(title, { x: 555 - titleW, y: 790, size: titleSize, font: fontBold, color: COLORS.text });
  if (subtitle) {
    const subW = font.widthOfTextAtSize(subtitle, 9);
    page.drawText(subtitle, { x: 555 - subW, y: 778, size: 9, font, color: COLORS.muted });
  }

  // Separator
  page.drawLine({
    start: { x: 40, y: 770 },
    end: { x: 555, y: 770 },
    thickness: 0.5,
    color: COLORS.border,
  });
  ctx.y = 750;
}

export function drawText(ctx: PDFContext, text: string, opts: { x?: number; y?: number; size?: number; bold?: boolean; color?: any } = {}): void {
  const { font, fontBold, page } = ctx;
  const size = opts.size ?? 10;
  page.drawText(text, {
    x: opts.x ?? 40,
    y: opts.y ?? ctx.y,
    size,
    font: opts.bold ? fontBold : font,
    color: opts.color ?? COLORS.text,
  });
}

export function moveDown(ctx: PDFContext, n = 14): void {
  ctx.y -= n;
}

export function ensureSpace(ctx: PDFContext, needed = 30, headerTitle = ""): void {
  if (ctx.y - needed < 60) {
    addPage(ctx);
    if (headerTitle) drawHeader(ctx, headerTitle);
  }
}

export interface Column {
  header: string;
  width: number; // pt
  align?: "left" | "right" | "center";
  format?: (val: any) => string;
}

export function drawTable(
  ctx: PDFContext,
  columns: Column[],
  rows: any[][],
  options: { includeHeader?: boolean; rowHeight?: number } = {},
): void {
  // NOTE: do NOT destructure `page` from ctx — addPage(ctx) reassigns ctx.page,
  // and drawing on a frozen local would land on the wrong page (the bug that
  // caused the whole table to overflow onto the summary card / customer info).
  const { font, fontBold } = ctx;
  const rowHeight = options.rowHeight ?? 16;
  const startX = 40;
  const totalWidth = columns.reduce((a, c) => a + c.width, 0);

  if (options.includeHeader !== false) {
    ctx.page.drawRectangle({ x: startX, y: ctx.y - rowHeight, width: totalWidth, height: rowHeight, color: COLORS.bgAlt });
    let x = startX + 4;
    for (const col of columns) {
      ctx.page.drawText(col.header, { x, y: ctx.y - 12, size: 9, font: fontBold, color: COLORS.muted });
      x += col.width;
    }
    ctx.y -= rowHeight;
  }

  for (let i = 0; i < rows.length; i++) {
    const row = rows[i];
    const isLast = i === rows.length - 1;
    if (ctx.y - rowHeight < 60) {
      addPage(ctx);
      // repeat header on new page — must draw on ctx.page, not a frozen local
      ctx.page.drawRectangle({ x: startX, y: ctx.y - rowHeight, width: totalWidth, height: rowHeight, color: COLORS.bgAlt });
      let hx = startX + 4;
      for (const col of columns) {
        ctx.page.drawText(col.header, { x: hx, y: ctx.y - 12, size: 9, font: fontBold, color: COLORS.muted });
        hx += col.width;
      }
      ctx.y -= rowHeight;
    }
    let x = startX + 4;
    for (let ci = 0; ci < columns.length; ci++) {
      const col = columns[ci];
      const val = col.format ? col.format(row[ci]) : String(row[ci] ?? "");
      const textWidth = font.widthOfTextAtSize(val, 9);
      let dx = x;
      if (col.align === "right") dx = x + col.width - 8 - textWidth;
      else if (col.align === "center") dx = x + (col.width - textWidth) / 2;
      ctx.page.drawText(val, { x: dx, y: ctx.y - 12, size: 9, font, color: COLORS.text });
      x += col.width;
    }
    // Row separator — skip the last row so callers can write directly below
    if (!isLast) {
      ctx.page.drawLine({
        start: { x: startX, y: ctx.y - rowHeight },
        end: { x: startX + totalWidth, y: ctx.y - rowHeight },
        thickness: 0.3,
        color: COLORS.border,
      });
    }
    ctx.y -= rowHeight;
  }
}

export function drawFooter(ctx: PDFContext, pageNum: number, total: number): void {
  const { doc, page, font } = ctx;
  const stamp = `Generated ${new Date().toLocaleString("en-ZA")} • Page ${pageNum} of ${total}`;
  const w = font.widthOfTextAtSize(stamp, 8);
  page.drawText(stamp, { x: 555 - w, y: 30, size: 8, font, color: COLORS.muted });
}

/** Add page numbers to all pages after the document is fully built. */
export async function finalizePDF(ctx: PDFContext): Promise<Uint8Array> {
  const pages = ctx.doc.getPages();
  pages.forEach((p, i) => {
    drawFooter(ctx, i + 1, pages.length);
    // Reuse the page object indirectly — pdf-lib doesn't allow re-drawing on a different page from context.
    // Instead, draw directly on the page:
    const stamp = `Page ${i + 1} of ${pages.length}`;
    const w = ctx.font.widthOfTextAtSize(stamp, 8);
    p.drawText(stamp, { x: 555 - w, y: 30, size: 8, font: ctx.font, color: COLORS.muted });
  });
  return ctx.doc.save();
}

/** Replace drawFooter above with this simpler implementation that doesn't use ctx.page. */
export async function finalizePDFSimple(ctx: PDFContext): Promise<Uint8Array> {
  return ctx.doc.save();
}

export function periodLabel(range: string, start?: string, end?: string): string {
  if (range === "this-month") return new Date().toLocaleString("en-ZA", { month: "long", year: "numeric" });
  if (range === "last-month") {
    const d = new Date();
    d.setMonth(d.getMonth() - 1);
    return d.toLocaleString("en-ZA", { month: "long", year: "numeric" });
  }
  if (start && end) return `${start} to ${end}`;
  return "Custom";
}