import { and, eq, gt, inArray, isNull, sql } from "drizzle-orm";
import { schema } from "@app/database";
import {
  computeCoverage,
  checkRecipeSafety,
  isRecipeSafe,
  type IngredientSafetyInfo,
  type PantryItem,
} from "@app/recipe-engine";
import type { MealType } from "@app/shared-types";
import type { WorkerContext } from "../context.js";

interface WeekPlanJobInput {
  weekPlanId: string;
  householdId: string;
  userId: string;
  input: {
    weekStartDate: string;
    daysToPlann?: number;
    mealTypes: MealType[];
    portionsPerMeal?: number;
    budgetMinorTotal?: number;
    preferLeftoversFirst: boolean;
    varietyLevel: "low" | "medium" | "high";
  };
}

/**
 * Veckoplansgenerering (spec §25). Deterministisk kärna:
 * 1. Matlådor planeras först (spec §24) när preferLeftoversFirst.
 * 2. Recept väljs på täckning + utgångsdatum + variation + budget.
 * 3. Samma recept upprepas inte inom planen (styrs av varietyLevel).
 * AAMOS (GENERATE_WEEK_PLAN) kan förfina ordningen men aldrig bryta reglerna.
 */
export async function processGenerateWeekPlan(
  ctx: WorkerContext,
  data: WeekPlanJobInput,
): Promise<void> {
  const { weekPlanId, householdId } = data;
  const [plan] = await ctx.db
    .select()
    .from(schema.weekPlans)
    .where(eq(schema.weekPlans.id, weekPlanId))
    .limit(1);
  if (!plan) return;

  const days = data.input.daysToPlann ?? 7;
  const mealTypes = data.input.mealTypes;
  const portions = data.input.portionsPerMeal ?? (await defaultPortions(ctx, householdId));

  // --- Lager & säkerhet ---
  const stockRows = await ctx.db
    .select({
      item: schema.inventoryItems,
      locationType: schema.storageLocations.type,
      shelfLife: schema.canonicalIngredients.shelfLifeGuidance,
      density: schema.canonicalIngredients.densityGPerMl,
      gramsPerPiece: schema.canonicalIngredients.gramsPerPiece,
    })
    .from(schema.inventoryItems)
    .innerJoin(
      schema.storageLocations,
      eq(schema.inventoryItems.storageLocationId, schema.storageLocations.id),
    )
    .leftJoin(
      schema.canonicalIngredients,
      eq(schema.inventoryItems.canonicalIngredientId, schema.canonicalIngredients.id),
    )
    .where(
      and(
        eq(schema.inventoryItems.householdId, householdId),
        isNull(schema.inventoryItems.depletedAt),
        gt(schema.inventoryItems.quantity, 0),
      ),
    );
  const pantry: PantryItem[] = stockRows.map((r) => ({
    id: r.item.id,
    canonicalIngredientId: r.item.canonicalIngredientId,
    quantity: r.item.quantity,
    unit: r.item.unit,
    bestBeforeDate: r.item.bestBeforeDate,
    useByDate: r.item.useByDate,
    openedAt: r.item.openedAt,
    frozenAt: r.item.frozenAt,
    thawedAt: r.item.thawedAt,
    purchasedAt: r.item.purchasedAt,
    storageLocationType: r.locationType,
    shelfLifeGuidance: r.shelfLife,
  }));
  const unitInfo = new Map(
    stockRows
      .filter((r) => r.item.canonicalIngredientId)
      .map((r) => [
        r.item.canonicalIngredientId!,
        { densityGPerMl: r.density, gramsPerPiece: r.gramsPerPiece },
      ]),
  );

  const members = await ctx.db
    .select({ userId: schema.householdMembers.userId })
    .from(schema.householdMembers)
    .where(eq(schema.householdMembers.householdId, householdId));
  const prefs = await ctx.db
    .select()
    .from(schema.userPreferences)
    .where(
      inArray(
        schema.userPreferences.userId,
        members.map((m) => m.userId),
      ),
    );
  const combinedAllergens = [...new Set(prefs.flatMap((p) => p.allergens))];
  const combinedAvoid = [...new Set(prefs.flatMap((p) => p.avoidIngredientIds))];
  const strictestSpice = prefs.length > 0 ? Math.min(...prefs.map((p) => p.spiceLevelMax)) : 5;

  // --- Kandidater ---
  const candidates = await ctx.db
    .select()
    .from(schema.recipes)
    .where(and(eq(schema.recipes.status, "published")))
    .limit(300);
  const allIngredients = await ctx.db
    .select()
    .from(schema.recipeIngredients)
    .where(
      inArray(
        schema.recipeIngredients.recipeId,
        candidates.map((c) => c.id),
      ),
    );
  const safetyRows = await ctx.db
    .select()
    .from(schema.canonicalIngredients)
    .where(
      inArray(schema.canonicalIngredients.id, [
        ...new Set(allIngredients.map((i) => i.canonicalIngredientId)),
      ]),
    );
  const safetyMap = new Map<string, IngredientSafetyInfo>(
    safetyRows.map((r) => [
      r.id,
      {
        id: r.id,
        allergens: r.allergens,
        isVegan: r.isVegan,
        isVegetarian: r.isVegetarian,
        containsGluten: r.containsGluten,
        containsLactose: r.containsLactose,
        isPork: r.isPork,
        isBeef: r.isBeef,
        isAlcohol: r.isAlcohol,
      },
    ]),
  );
  for (const r of safetyRows) {
    if (!unitInfo.has(r.id))
      unitInfo.set(r.id, { densityGPerMl: r.densityGPerMl, gramsPerPiece: r.gramsPerPiece });
  }

  const scored = candidates
    .filter((recipe) => {
      const ings = allIngredients.filter((i) => i.recipeId === recipe.id);
      const violations = checkRecipeSafety(
        {
          ingredients: ings.map((i) => ({
            canonicalIngredientId: i.canonicalIngredientId,
            optional: i.optional,
          })),
          spiceLevel: recipe.spiceLevel,
        },
        {
          allergens: combinedAllergens,
          avoidIngredientIds: combinedAvoid,
          spiceLevelMax: strictestSpice,
        },
        safetyMap,
      );
      return isRecipeSafe(violations);
    })
    .map((recipe) => {
      const ings = allIngredients
        .filter((i) => i.recipeId === recipe.id)
        .map((i) => ({
          canonicalIngredientId: i.canonicalIngredientId,
          displayNameSv: i.displayNameSv,
          quantity: i.quantity,
          unit: i.unit,
          optional: i.optional,
        }));
      const coverage = computeCoverage(ings, pantry, unitInfo);
      const expiryBoost = coverage.expiringUsed.length > 0 ? 0.3 : 0;
      const budgetOk =
        data.input.budgetMinorTotal == null ||
        recipe.estimatedCostMinorPerPortion == null ||
        recipe.estimatedCostMinorPerPortion * portions <=
          (data.input.budgetMinorTotal / (days * mealTypes.length)) * 1.5;
      return {
        recipe,
        coverage,
        score: coverage.coverage + expiryBoost + (budgetOk ? 0 : -0.5),
      };
    })
    .sort((a, b) => b.score - a.score);

  // --- Matlådor först (spec §24) ---
  const mealBoxes = data.input.preferLeftoversFirst
    ? await ctx.db
        .select()
        .from(schema.mealBoxes)
        .where(
          and(
            eq(schema.mealBoxes.householdId, householdId),
            eq(schema.mealBoxes.status, "available"),
          ),
        )
        .orderBy(schema.mealBoxes.recommendedUseBy)
    : [];

  // --- Bygg planen ---
  const usedRecipeIds = new Set<string>();
  const repeatLimit = data.input.varietyLevel === "low" ? 2 : 1;
  const recipeUseCount = new Map<string, number>();
  let boxIndex = 0;
  let candidateIndex = 0;
  const entries: Array<typeof schema.weekPlanEntries.$inferInsert> = [];

  for (let day = 0; day < days; day++) {
    const date = new Date(Date.parse(data.input.weekStartDate) + day * 86_400_000)
      .toISOString()
      .slice(0, 10);
    for (const mealType of mealTypes) {
      // Matlåda om det finns och portionerna räcker
      const box = mealBoxes[boxIndex];
      if (box && box.portionsRemaining >= Math.min(portions, 2)) {
        entries.push({
          weekPlanId,
          date,
          mealType,
          mealBoxId: box.id,
          titleSv: `${box.titleSv} (matlåda)`,
          portions: Math.min(box.portionsRemaining, portions),
          status: "planned",
          rescheduleReasonSv: `Matlådan bör användas senast ${box.recommendedUseBy}.`,
          sortOrder: entries.length,
        });
        boxIndex++;
        continue;
      }
      // Nästa bästa recept som passar måltidstyp och variationsregeln
      let chosen = null;
      for (let i = 0; i < scored.length; i++) {
        const idx = (candidateIndex + i) % scored.length;
        const candidate = scored[idx]!;
        if (!candidate.recipe.mealTypes.includes(mealType)) continue;
        const used = recipeUseCount.get(candidate.recipe.id) ?? 0;
        if (used >= repeatLimit) continue;
        chosen = candidate;
        candidateIndex = idx + 1;
        break;
      }
      if (!chosen) continue;
      recipeUseCount.set(chosen.recipe.id, (recipeUseCount.get(chosen.recipe.id) ?? 0) + 1);
      usedRecipeIds.add(chosen.recipe.id);
      const expiring = chosen.coverage.expiringUsed[0];
      entries.push({
        weekPlanId,
        date,
        mealType,
        recipeId: chosen.recipe.id,
        titleSv: chosen.recipe.titleSv,
        portions,
        status: "planned",
        rescheduleReasonSv: expiring
          ? `Använder ${expiring.displayNameSv.toLowerCase()} som bör ätas snart.`
          : null,
        sortOrder: entries.length,
      });
    }
  }

  await ctx.db
    .delete(schema.weekPlanEntries)
    .where(eq(schema.weekPlanEntries.weekPlanId, weekPlanId));
  if (entries.length > 0) await ctx.db.insert(schema.weekPlanEntries).values(entries);
  await ctx.db
    .update(schema.weekPlans)
    .set({ status: "draft", updatedAt: new Date() })
    .where(eq(schema.weekPlans.id, weekPlanId));

  await ctx.db.insert(schema.domainEvents).values({
    type: "WEEK_PLAN_UPDATED",
    userId: data.userId,
    householdId,
    payload: { weekPlanId, reason: "generated" },
  });
}

async function defaultPortions(ctx: WorkerContext, householdId: string): Promise<number> {
  const [row] = await ctx.db
    .select({ total: sql<number>`coalesce(sum(${schema.householdMembers.portionFactor}), 2)` })
    .from(schema.householdMembers)
    .where(eq(schema.householdMembers.householdId, householdId));
  return Math.max(1, Math.round(Number(row?.total ?? 2)));
}