"use client";

import { AlertCircle, RotateCcw, ShoppingBag, X } from "lucide-react";
import { useCallback, useEffect, useMemo, useState, useTransition } from "react";
import { generateMealPlanAction } from "@/app/actions";
import { Cart, buildGroceryList } from "@/app/lib/grocery";
import { activeRecipeIds } from "@/app/lib/plan";
import { averageGroceryProvider } from "@/app/lib/pricing";
import { RECIPES } from "@/app/lib/recipes";
import { usePlanState } from "@/app/lib/usePlanState";
import type { FillMode } from "@/app/types";
import { BudgetMeter } from "./BudgetMeter";
import { ConfigPanel } from "./ConfigPanel";
import { GroceryListDrawer, GrocerySummaryPanel } from "./GroceryListDrawer";
import { IngredientPanel } from "./IngredientPanel";
import { MealGrid } from "./MealGrid";
import { MealSelectorModal } from "./MealSelectorModal";
import { Navbar } from "./Navbar";
import { RecipeDialog } from "./RecipeDialog";

interface UndoSnapshot {
  message: string;
  previousSlots: Record<string, string>;
}

export default function PlannerDashboard() {
  const { state, dispatch, syncStatus } = usePlanState();
  const [isGenerating, startGenerating] = useTransition();
  const [notes, setNotes] = useState<string[]>([]);
  const [openSlot, setOpenSlot] = useState<string | null>(null);
  const [viewSlot, setViewSlot] = useState<string | null>(null);
  const [groceriesOpen, setGroceriesOpen] = useState(false);
  const [undo, setUndo] = useState<UndoSnapshot | null>(null);

  // Auto-dismiss undo toast after 6 seconds
  useEffect(() => {
    if (!undo) return;
    const timer = window.setTimeout(() => setUndo(null), 6000);
    return () => window.clearTimeout(timer);
  }, [undo]);

  const summary = useMemo(
    () => buildGroceryList(activeRecipeIds(state), { householdSize: state.householdSize, onHandItems: state.onHandItems }),
    [state],
  );

  const mealCosts = useMemo(() => {
    const emptyCart = new Cart({ householdSize: state.householdSize, onHandItems: state.onHandItems });
    return new Map(RECIPES.map((r) => [r.id, emptyCart.marginal(r.id).eaten]));
  }, [state.householdSize, state.onHandItems]);

  function handleGenerate(fillMode: FillMode) {
    startGenerating(async () => {
      try {
        const result = await generateMealPlanAction({ state, fillMode, seed: Date.now() });
        dispatch({ type: "replaceSlots", slots: result.slots });
        setNotes(result.notes);
        setUndo(null);
      } catch {
        setNotes(["Couldn't reach the planner. Check your connection and try again."]);
      }
    });
  }

  const handleRemoveSlot = useCallback(
    (key: string, recipeTitle: string) => {
      setUndo({ message: `Removed "${recipeTitle}"`, previousSlots: { ...state.slots } });
      dispatch({ type: "setSlot", key, recipeId: null });
    },
    [dispatch, state.slots],
  );

  const handleClearWeek = useCallback(() => {
    const count = activeRecipeIds(state).length;
    if (count === 0) return;
    setUndo({ message: `Cleared ${count} planned meal${count === 1 ? "" : "s"}`, previousSlots: { ...state.slots } });
    dispatch({ type: "clearSlots" });
  }, [dispatch, state]);

  const handleUndo = useCallback(() => {
    if (!undo) return;
    dispatch({ type: "replaceSlots", slots: undo.previousSlots });
    setUndo(null);
  }, [dispatch, undo]);

  const closeSelector = useCallback(() => setOpenSlot(null), []);
  const closeRecipe = useCallback(() => setViewSlot(null), []);
  const closeGroceries = useCallback(() => setGroceriesOpen(false), []);
  const toggleOnHand = useCallback(
    (itemId: string, onHand: boolean) => dispatch({ type: "setItemPreference", itemIds: [itemId], preference: onHand ? "have" : "use" }),
    [dispatch],
  );

  const mealCount = activeRecipeIds(state).length;

  return (
    <>
      <Navbar checkoutTotal={summary.checkoutTotal} budget={state.targetBudget} syncStatus={syncStatus} isGenerating={isGenerating} />

      <main className="mx-auto max-w-7xl px-4 pt-6 pb-28 sm:px-6 lg:pb-12">
        <div className="grid grid-cols-1 gap-6 lg:grid-cols-3">
          {/* Left: compact control bar -> immediate MealGrid -> Pantry below */}
          <div className="space-y-6 lg:col-span-2">
            <ConfigPanel
              state={state}
              dispatch={dispatch}
              onGenerate={handleGenerate}
              onClear={handleClearWeek}
              isGenerating={isGenerating}
            />

            {notes.length > 0 && (
              <div
                role="status"
                className="flex items-start justify-between gap-3 rounded-xl border border-status-warn-line bg-status-warn-bg p-3.5 text-sm text-status-warn"
              >
                <div className="flex items-start gap-2.5">
                  <AlertCircle className="mt-0.5 size-4 shrink-0" aria-hidden />
                  <ul className="space-y-1">
                    {notes.map((note) => (
                      <li key={note}>{note}</li>
                    ))}
                  </ul>
                </div>
                <button
                  type="button"
                  onClick={() => setNotes([])}
                  aria-label="Dismiss notice"
                  className="grid size-8 shrink-0 place-items-center rounded-lg hover:bg-black/5"
                >
                  <X className="size-4" aria-hidden />
                </button>
              </div>
            )}

            <div className={isGenerating ? "pointer-events-none opacity-60 transition-opacity" : "transition-opacity"}>
              <MealGrid
                state={state}
                dispatch={dispatch}
                mealCosts={mealCosts}
                onOpenSlot={setOpenSlot}
                onViewSlot={setViewSlot}
                onRemoveSlot={handleRemoveSlot}
              />
            </div>

            <IngredientPanel state={state} dispatch={dispatch} />
          </div>

          {/* Right: persistent Market Receipt summary (desktop) */}
          <aside className="hidden lg:block">
            <div className="sticky top-20 max-h-[calc(100dvh-6rem)] overflow-y-auto rounded-xl border border-line bg-surface p-5">
              <h2 className="mb-3 font-serif text-xl font-semibold">Market receipt</h2>
              <GrocerySummaryPanel
                summary={summary}
                budget={state.targetBudget}
                priceSourceLabel={averageGroceryProvider.label}
                onToggleOnHand={toggleOnHand}
              />
            </div>
          </aside>
        </div>
      </main>

      {/* Undo Toast for accidental meal removal or Clear */}
      {undo && (
        <div
          role="status"
          aria-live="polite"
          className="fixed bottom-20 left-1/2 z-40 flex -translate-x-1/2 items-center gap-3 rounded-xl border border-line-strong bg-surface px-4 py-2.5 text-sm shadow-lg lg:bottom-6"
        >
          <span className="text-ink">{undo.message}</span>
          <button
            type="button"
            onClick={handleUndo}
            className="trim-cap inline-flex min-h-8 items-center gap-1.5 rounded-lg bg-brand-600 px-3 py-1 text-xs font-semibold text-on-accent hover:bg-brand-500"
          >
            <RotateCcw className="size-3.5" aria-hidden />
            Undo
          </button>
          <button
            type="button"
            onClick={() => setUndo(null)}
            aria-label="Dismiss undo"
            className="grid size-7 place-items-center rounded text-ink-faint hover:text-ink"
          >
            <X className="size-3.5" aria-hidden />
          </button>
        </div>
      )}

      {/* Mobile: sticky bottom bar */}
      <div className="fixed inset-x-0 bottom-0 z-30 border-t border-line bg-surface/95 px-4 py-3 backdrop-blur-md lg:hidden">
        <div className="mx-auto flex max-w-7xl items-center gap-4">
          <div className="flex-1">
            <BudgetMeter spent={summary.checkoutTotal} budget={state.targetBudget} compact />
          </div>
          <button
            type="button"
            onClick={() => setGroceriesOpen(true)}
            className="trim-cap inline-flex min-h-10 shrink-0 items-center gap-2 rounded-lg bg-brand-600 px-4 py-2 text-sm font-semibold text-on-accent shadow-2xs hover:bg-brand-500"
          >
            <ShoppingBag className="size-4" strokeWidth={2} aria-hidden />
            Receipt ({summary.lines.length})
          </button>
        </div>
        <p className="sr-only" aria-live="polite">
          {mealCount} meals planned, estimated checkout {summary.checkoutTotal.toFixed(2)} dollars
        </p>
      </div>

      <GroceryListDrawer
        open={groceriesOpen}
        onClose={closeGroceries}
        summary={summary}
        budget={state.targetBudget}
        priceSourceLabel={averageGroceryProvider.label}
        onToggleOnHand={toggleOnHand}
      />

      <RecipeDialog
        slotKey={viewSlot}
        state={state}
        onClose={closeRecipe}
        onSwap={(key) => {
          setViewSlot(null);
          setOpenSlot(key);
        }}
        onRemove={(key, title) => {
          handleRemoveSlot(key, title);
          setViewSlot(null);
        }}
      />

      <MealSelectorModal
        slotKey={openSlot}
        state={state}
        onClose={closeSelector}
        onPick={(recipeId) => {
          if (openSlot) dispatch({ type: "setSlot", key: openSlot, recipeId });
          setOpenSlot(null);
        }}
      />
    </>
  );
}