import type { jsPDF as JsPDF } from "jspdf";
import type { MealPlanState } from "@/app/types";
import { ingredientLines } from "./display";
import { activeSlots, mealLabel } from "./plan";
import { RECIPES_BY_ID } from "./recipes";

// ---------------------------------------------------------------------------
// Downloadable weekly plan as a PDF, organized by day, with the full recipe
// (scaled ingredients + steps) under every planned meal.
//
// Two layers: `buildPlanModel` (pure, tested) decides the content;
// `renderPlanPdf` lays it out with jsPDF. The planner loads jsPDF on click.
// ---------------------------------------------------------------------------

const FULL_DAY_NAMES = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"];

interface PlannedMeal {
  label: string;
  title: string;
  meta: string;
  description: string;
  ingredients: string[];
  steps: string[];
  tip?: string;
}

interface PlanModel {
  intro: string;
  days: { name: string; meals: (PlannedMeal | { label: string; empty: true })[] }[];
}

type PlanInput = Pick<MealPlanState, "daysCount" | "mealsPerDay" | "slots" | "householdSize">;

export function buildPlanModel(state: PlanInput): PlanModel {
  const servings = state.householdSize;
  const slots = activeSlots(state);
  return {
    intro: `${state.daysCount} day${state.daysCount === 1 ? "" : "s"} · ingredients scaled for ${servings} ${
      servings === 1 ? "person" : "people"
    }. Step wording follows each recipe's original batch size.`,
    days: FULL_DAY_NAMES.slice(0, state.daysCount).map((name, dayIndex) => ({
      name,
      meals: slots
        .filter((s) => s.dayIndex === dayIndex)
        .map((s) => {
          const label = mealLabel(s.mealNumber);
          const recipe = s.recipeId ? RECIPES_BY_ID.get(s.recipeId) : undefined;
          if (!recipe) return { label, empty: true as const };
          return {
            label,
            title: recipe.title,
            meta: `${recipe.prepTime} min · serves ${servings}`,
            description: recipe.description,
            ingredients: ingredientLines(recipe, servings).map(
              (l) => `${l.quantity} ${l.unit} ${l.name}${l.detail ? ` (${l.detail})` : ""}`,
            ),
            steps: recipe.steps,
            tip: recipe.tip,
          };
        }),
    })),
  };
}

// jsPDF's built-in Helvetica only covers WinAnsi (Latin-1 + a few symbols).
const SPELLED: Record<string, string> = { "⅓": " 1/3", "⅔": " 2/3", "⅛": " 1/8", "ı": "i" };
const WINANSI_EXTRA = new Set("€‚ƒ„…†‡ˆ‰Š‹ŒŽ‘’“”•–—˜™š›œžŸ");

/** Make text printable in the base PDF font: spell out ⅓-style fractions, decompose or drop anything else. */
export function pdfSafe(text: string): string {
  let out = "";
  for (const ch of text) {
    const code = ch.codePointAt(0)!;
    if (code <= 0x7e || (code >= 0xa0 && code <= 0xff) || WINANSI_EXTRA.has(ch)) out += ch;
    else if (SPELLED[ch]) out += SPELLED[ch];
    else out += ch.normalize("NFKD").replace(/[^\x20-\x7e]/g, "");
  }
  // "⅓ cup" → " 1/3 cup": drop the space the spelling adds when nothing precedes it.
  return out.replace(/(^|\s) (\d\/\d)/g, "$1$2");
}

const ACCENT: [number, number, number] = [206, 87, 68]; // matches the app's salmon accent-500
const INK: [number, number, number] = [30, 37, 48];
const MUTED: [number, number, number] = [74, 85, 101];

/** Lay the plan out on US Letter pages; one day per page, recipes never split mid-line. */
export function renderPlanPdf(model: PlanModel, JsPdf: typeof JsPDF): JsPDF {
  const doc = new JsPdf({ unit: "pt", format: "letter" });
  const pageW = doc.internal.pageSize.getWidth();
  const pageH = doc.internal.pageSize.getHeight();
  const margin = 54;
  const width = pageW - margin * 2;
  let y = margin;

  const ensure = (height: number) => {
    if (y + height > pageH - margin) {
      doc.addPage();
      y = margin;
    }
  };

  const write = (text: string, opts: { size: number; bold?: boolean; color?: [number, number, number]; indent?: number; gap?: number }) => {
    const indent = opts.indent ?? 0;
    const lineH = opts.size * 1.4;
    doc.setFont("helvetica", opts.bold ? "bold" : "normal").setFontSize(opts.size).setTextColor(...(opts.color ?? INK));
    for (const line of doc.splitTextToSize(pdfSafe(text), width - indent) as string[]) {
      ensure(lineH);
      doc.text(line, margin + indent, y + opts.size);
      y += lineH;
    }
    y += opts.gap ?? 0;
  };

  /** Numbered/bulleted item with a hanging indent so wrapped lines align under the text. */
  const item = (marker: string, text: string) => {
    const size = 10.5;
    const lineH = size * 1.4;
    doc.setFont("helvetica", "normal").setFontSize(size).setTextColor(...INK);
    const lines = doc.splitTextToSize(pdfSafe(text), width - 20) as string[];
    lines.forEach((line, i) => {
      ensure(lineH);
      if (i === 0) doc.text(marker, margin + 4, y + size);
      doc.text(line, margin + 20, y + size);
      y += lineH;
    });
    y += 2;
  };

  write("My meal plan", { size: 24, bold: true, gap: 4 });
  write(model.intro, { size: 10.5, color: MUTED, gap: 16 });

  model.days.forEach((day, dayIndex) => {
    if (dayIndex > 0) {
      doc.addPage();
      y = margin;
    }
    write(day.name, { size: 18, bold: true, gap: 2 });
    doc.setDrawColor(...ACCENT).setLineWidth(1.5).line(margin, y, margin + width, y);
    y += 14;

    for (const meal of day.meals) {
      ensure(80); // keep a meal's heading with the start of its recipe
      write(meal.label.toUpperCase(), { size: 9, bold: true, color: ACCENT, gap: 2 });
      if ("empty" in meal) {
        write("Nothing planned", { size: 10.5, color: MUTED, gap: 16 });
        continue;
      }
      write(meal.title, { size: 14, bold: true });
      write(meal.meta, { size: 9.5, color: MUTED, gap: 4 });
      write(meal.description, { size: 10.5, gap: 8 });
      write("Ingredients", { size: 11, bold: true, gap: 2 });
      meal.ingredients.forEach((line) => item("•", line));
      y += 6;
      write("Steps", { size: 11, bold: true, gap: 2 });
      meal.steps.forEach((step, i) => item(`${i + 1}.`, step));
      if (meal.tip) {
        y += 4;
        write(`Tip: ${meal.tip}`, { size: 10, color: MUTED });
      }
      y += 18;
    }
  });

  const pages = doc.getNumberOfPages();
  for (let page = 1; page <= pages; page++) {
    doc.setPage(page).setFont("helvetica", "normal").setFontSize(8.5).setTextColor(...MUTED);
    doc.text(`Plan my Meals · page ${page} of ${pages}`, pageW / 2, pageH - 28, { align: "center" });
  }
  return doc;
}