/**
 * Orders, the ledger, favourites and custom orders.
 * Rules: docs/DATA-MIGRATION-MAP.md §7, §8, §10, §10.7.
 */
import {
  LedgerCurrency,
  LedgerDirection,
  LedgerSourceType,
  OrderChannel,
  OrderStatus,
  PreOrderStatus,
  Prisma,
} from '@prisma/client';
import { upsert, type Ctx } from '../lib/context';
import { grams, int, jalaliDate, percent, rial, tehran, text, toNumber } from '../lib/normalize';

type Row = Record<string, unknown>;
const D = Prisma.Decimal;

/** Order::$STS (Order.php:66-74). 7 «کنسل شده» is commented out in legacy and absent from the data. */
const ORDER_STATUS: Record<number, OrderStatus> = {
  0: OrderStatus.SUSPENDED,
  1: OrderStatus.PLACED,
  2: OrderStatus.ADMIN_APPROVED,
  3: OrderStatus.SOURCING,
  4: OrderStatus.PREPARING,
  5: OrderStatus.DELIVERED_TO_AGENT,
  6: OrderStatus.DELIVERED_TO_CUSTOMER,
};

/* ───────────── orders ───────────── */

export async function orders(ctx: Ctx) {
  const S = 'orders';
  // Wholesale only. Retail `orders_orders` is deferred by the owner (§7.2) and
  // must not be mapped with this status table: its 7 means «تحویل مشتری».
  const rows = await ctx.q<Row>('SELECT * FROM orders WHERE deleted_at IS NULL');
  for (const r of rows) {
    const customerId = ctx.map.get('customer', r.customer_id);
    if (!customerId) {
      ctx.report.count(S, 'skipped: customer not migrated');
      ctx.report.note(S, `legacy order #${String(r.id)} skipped: its customer #${String(r.customer_id)} was not migrated (status ${String(r.sts)})`);
      continue;
    }
    const sts = int(r.sts);
    const status = sts !== null ? ORDER_STATUS[sts] : undefined;
    if (!status) {
      ctx.report.count(S, 'skipped: unknown status');
      ctx.report.note(S, `legacy order #${String(r.id)} has status ${String(r.sts)}, which has no mapping`);
      continue;
    }
    const orderNumber = `H-${String(r.id)}`;
    // `orders.reagent_id` is the expert the order was credited to when it was
    // placed (never moved afterwards) — carried as is, NOT re-derived from the
    // customer's current referrer (owner ruling 2026-10-08). It names a
    // Customer row in legacy: an expert maps to their AdminUser; anyone else
    // (one customer, 17 orders from 2022) is kept as the referrer customer.
    let salesAgentId: string | null = null;
    let referrerCustomerId: string | null = null;
    if (r.reagent_id !== null) {
      salesAgentId = ctx.map.get('expert', r.reagent_id) ?? null;
      if (!salesAgentId) referrerCustomerId = ctx.map.get('customer', r.reagent_id) ?? null;
      if (!salesAgentId && !referrerCustomerId) {
        ctx.report.count(S, 'placing expert not migrated — left empty');
        ctx.report.note(S, `legacy order #${String(r.id)}: its reagent #${String(r.reagent_id)} was not migrated`);
      } else {
        ctx.report.count(S, salesAgentId ? 'credited to its legacy expert' : 'credited to its legacy referrer customer');
      }
    }
    const data = {
      salesAgentId,
      referrerCustomerId,
      customerId,
      channel: OrderChannel.WHOLESALE,
      status,
      // `input` is what legacy debits (CustomerController::updateRemain) and
      // equals `w` on all 300 live orders; `wage` is the making-charge part of it.
      totalGoldWeightGrams: grams(r.input),
      wageWeightGrams: grams(r.wage),
      flatRialCharge: rial(r.rial_input),
      // Legacy 0 «معلق» is the over-credit-limit hold.
      isSuspendedOverCreditLimit: sts === 0,
      // Legacy records no delivery time; the last change of a delivered order is the best available.
      deliveredAt: sts === 6 ? tehran(r.updated_at) : null,
    };
    const res = await upsert(ctx, 'order', r.id, {
      exists: async (id) => !!(await ctx.db.order.findUnique({ where: { id } })),
      find: () => ctx.db.order.findUnique({ where: { orderNumber }, select: { id: true } }),
      create: () => ctx.db.order.create({ data: { ...data, orderNumber, createdAt: tehran(r.created_at) ?? undefined } }),
      update: async (id, how) => {
        if (how === 'created') await ctx.db.order.update({ where: { id }, data });
      },
    });
    ctx.report.count(S, `${res.isNew ? 'created' : 'updated'} — ${status}`);  }
  await orderItems(ctx);
}

async function orderItems(ctx: Ctx) {
  const S = 'order lines';
  const rows = await ctx.q<Row>(
    `SELECT oi.* FROM order_items oi JOIN orders o ON o.id = oi.order_id AND o.deleted_at IS NULL
     WHERE oi.deleted_at IS NULL`,
  );
  for (const r of rows) {
    const orderId = ctx.map.get('order', r.order_id);
    if (!orderId) continue;
    const productVariantId = ctx.map.get('variant', r.variant_id);
    if (!productVariantId) {
      ctx.report.count(S, 'skipped: variant not migrated');
      ctx.report.note(S, `legacy order line #${String(r.id)} (order #${String(r.order_id)}) lost: variant #${String(r.variant_id)} not found`);
      continue;
    }
    const data = {
      orderId,
      productVariantId,
      quantity: int(r.qty) ?? 1,
      rashWeightGramsSnapshot: grams(r.rash_weight),
      wagePercentSnapshot: percent(r.percent),
      discountPercentSnapshot: percent(r.discount),
      computedWeightGrams: grams(r.w),
      flatRialCharge: rial(r.rial_pay),
    };
    const res = await upsert(ctx, 'orderitem', r.id, {
      exists: async (id) => !!(await ctx.db.orderItem.findUnique({ where: { id } })),
      find: async () => null,
      create: () => ctx.db.orderItem.create({ data }),
      update: async (id) => {
        await ctx.db.orderItem.update({ where: { id }, data });
      },
    });
    ctx.report.count(S, res.isNew ? 'created' : 'updated');
    // §7.4: the target keeps one snapshot; legacy's audit pair is lost.
    if (toNumber(r.original_rash_weight) !== toNumber(r.rash_weight) || toNumber(r.original_percent) !== toNumber(r.percent)) {
      ctx.report.count(S, 'weight or wage edited after ordering (original_* not carried)');
    }
  }
}

/* ───────────── ledger ───────────── */

/** Cash::$TYPES (Major/Cash.php:56-62). Type 9 «سفارش» is handled from `orders`. */
const CASH_SOURCE: Record<number, LedgerSourceType> = {
  1: LedgerSourceType.REPAYMENT_MELTED_GOLD,
  2: LedgerSourceType.REPAYMENT_TRANSFER,
  3: LedgerSourceType.REPAYMENT_CHEQUE,
  4: LedgerSourceType.REPAYMENT_CASH,
};

/** Grams per mesghal. Legacy's price_per_gram is per mesghal (CashController.php:68). */
const MESGHAL = 4.331802;

/**
 * Legacy debt is COMPUTED, never posted (CustomerController::updateRemain):
 *
 *   remain      = Σ orders.input     (sts > 4)  −  Σ cashes.value (confirmed, type 1–4)
 *   rial_remain = Σ orders.rial_input (sts > 4)
 *
 * so the ledger is rebuilt from exactly those rows. Recomputing that formula on
 * the 2026-10-04 dump reproduces the stored balance for 1,590 of 1,591
 * customers to 0.0001 g (§10.7). Consequences:
 *  - `cashes` type 9 («سفارش») is NOT carried: it mirrors an order, and the
 *    order already posts that debt. Both would count it twice.
 *  - Rials paid (types 3/4 `price`) never reduce rial debt; a cash payment is
 *    converted to gold (`value`) and reduces the gold debt. Kept as is.
 *  - A balance the records cannot explain (customer #125: −9.8951 g, set by
 *    hand after its only document was deleted) is carried as an explicit
 *    ADJUSTMENT entry, so the customer sees the same number (owner, 2026-10-07).
 */
export async function ledger(ctx: Ctx) {
  const S = 'ledger';
  const entry = async (key: string, data: Prisma.LedgerEntryUncheckedCreateInput) => {
    const res = await upsert(ctx, 'ledger', key, {
      exists: async (id) => !!(await ctx.db.ledgerEntry.findUnique({ where: { id } })),
      find: async () => null,
      create: () => ctx.db.ledgerEntry.create({ data }),
      update: async (id) => {
        await ctx.db.ledgerEntry.update({ where: { id }, data });
      },
    });
    return res.id;
  };
  const signed = (amount: number) => ({
    direction: amount >= 0 ? LedgerDirection.DEBIT : LedgerDirection.CREDIT,
    amount: grams(Math.abs(amount)),
  });

  // Orders delivered to the agent or the customer carry the debt.
  const delivered = await ctx.q<Row>('SELECT * FROM orders WHERE deleted_at IS NULL AND sts > 4');
  for (const o of delivered) {
    const customerId = ctx.map.get('customer', o.customer_id);
    const orderId = ctx.map.get('order', o.id);
    if (!customerId || !orderId) continue;
    const at = tehran(o.updated_at) ?? undefined;
    if (toNumber(o.input) !== 0) {
      await entry(`order:${String(o.id)}:gold`, {
        customerId, orderId, ...signed(toNumber(o.input)),
        currency: LedgerCurrency.GOLD_GRAM, sourceType: LedgerSourceType.ORDER_STOCK,
        confirmed: true, confirmedAt: at, createdAt: at,
        note: 'بدهی وزنی سفارش — انتقال از سیستم قدیم',
      });
      ctx.report.count(S, 'order debt (gold)');
    }
    if (toNumber(o.rial_input) !== 0) {
      const amt = toNumber(o.rial_input);
      await entry(`order:${String(o.id)}:rial`, {
        customerId, orderId,
        direction: amt >= 0 ? LedgerDirection.DEBIT : LedgerDirection.CREDIT,
        amount: rial(Math.abs(amt)),
        currency: LedgerCurrency.RIAL, sourceType: LedgerSourceType.ORDER_STOCK,
        confirmed: true, confirmedAt: at, createdAt: at,
        note: 'بدهی ریالی سفارش — انتقال از سیستم قدیم',
      });
      ctx.report.count(S, 'order debt (rial)');
    }
  }

  const cashes = await ctx.q<Row>('SELECT * FROM cashes WHERE deleted_at IS NULL');
  for (const c of cashes) {
    const type = int(c.type);
    if (type === 9) {
      ctx.report.count(S, 'cash type 9 (order mirror) skipped — debt comes from the order');
      continue;
    }
    const sourceType = type !== null ? CASH_SOURCE[type] : undefined;
    if (!sourceType) {
      ctx.report.count(S, 'skipped: unknown document type');
      ctx.report.note(S, `legacy document #${String(c.id)} has type ${String(c.type)}`);
      continue;
    }
    const customerId = ctx.map.get('customer', c.customer_id);
    if (!customerId) {
      ctx.report.count(S, 'skipped: customer not migrated');
      continue;
    }
    // A repayment is a CREDIT; a negative `value` (4 transfers) is a debit.
    const value = toNumber(c.value);
    const received = jalaliDate(c.recive_date);
    const confirmed = int(c.confirmed) === 1;
    const ppg = toNumber(c.price_per_gram);
    await entry(`cash:${String(c.id)}`, {
      customerId,
      currency: LedgerCurrency.GOLD_GRAM,
      direction: value >= 0 ? LedgerDirection.CREDIT : LedgerDirection.DEBIT,
      amount: grams(Math.abs(value)),
      sourceType,
      confirmed,
      confirmedAt: confirmed ? tehran(c.updated_at) : null,
      postedByAdminUserId: ctx.map.get('admin', c.user_id) ?? null,
      karatPerMille: int(c.ayar),
      labName: text(c.lab),
      hallmark: text(c.ang),
      accountName: text(c.account_name),
      bankName: text(c.bank_name),
      transferTo: text(c.to),
      originalValue: c.original_value === null ? null : grams(c.original_value),
      priceRial: c.price === null ? null : rial(c.price),
      pricePerGramRialAtEntry: ppg ? rial(ppg / MESGHAL) : null,
      receivedAt: received,
      // The raw Jalali text is kept in the note when it did not parse.
      note: [text(c.title), text(c.note), !received && text(c.recive_date) ? `تاریخ دریافت: ${text(c.recive_date)}` : null]
        .filter(Boolean).join(' — ') || null,
      createdAt: tehran(c.created_at) ?? undefined,
    });
    ctx.report.count(S, `document ${sourceType}${confirmed ? '' : ' (unconfirmed — not in the balance)'}`);
  }

  await balances(ctx);
}

/**
 * Per migrated customer: compare what the import posted with the balance legacy
 * stored, carry any real difference as one ADJUSTMENT entry, then set the
 * cached balance to the sum of ALL confirmed entries (the rule every other
 * ledger path keeps: confirmed DEBIT adds, confirmed CREDIT subtracts).
 */
async function balances(ctx: Ctx) {
  const S = 'balances';
  const legacy = await ctx.q<Row>('SELECT id, remain, rial_remain FROM customers WHERE deleted_at IS NULL');
  const stored = new Map<string, { gold: number; rial: number }>();
  for (const r of legacy) {
    const target = ctx.map.get('customer', r.id);
    if (!target) continue;
    const cur = stored.get(target) ?? { gold: 0, rial: 0 };
    cur.gold += toNumber(r.remain);
    cur.rial += toNumber(r.rial_remain);
    stored.set(target, cur);
  }

  const importedIds = new Set<string>();
  for (const row of await ctx.db.$queryRawUnsafe<{ target_id: string }[]>(
    `SELECT target_id FROM legacy_import.id_map WHERE entity = 'ledger' AND legacy_id NOT LIKE 'adjust:%'`,
  )) importedIds.add(row.target_id);

  // Up to this a difference is the double → Decimal(14,4) rounding of §4, not a
  // real gap — inclusive: the first run posted two −0.0001 "adjustments" that
  // were nothing but rounding, and would have shown on those statements.
  const TOLERANCE = 0.0001;

  for (const [customerId, want] of stored) {
    const entries = await ctx.db.ledgerEntry.findMany({ where: { customerId, confirmed: true } });
    const sum = (currency: LedgerCurrency, onlyImported: boolean) =>
      entries
        .filter((e) => e.currency === currency && (!onlyImported || importedIds.has(e.id)))
        .reduce((acc, e) => (e.direction === LedgerDirection.DEBIT ? acc.add(e.amount) : acc.sub(e.amount)), new D(0));

    for (const [currency, wanted, label] of [
      [LedgerCurrency.GOLD_GRAM, want.gold, 'gold'],
      [LedgerCurrency.RIAL, want.rial, 'rial'],
    ] as const) {
      const key = `adjust:${customerId}:${label}`;
      const diff = new D(wanted.toFixed(4)).sub(sum(currency, true));
      const existing = ctx.map.get('ledger', key);
      if (diff.abs().lte(TOLERANCE)) {
        if (!diff.isZero()) ctx.report.count(S, `rounding-only difference (${label}, ≤ ${TOLERANCE}) — no adjustment`);
        if (existing) {
          await ctx.db.ledgerEntry.deleteMany({ where: { id: existing } });
          await ctx.map.drop('ledger', key);
        }
        continue;
      }
      const data: Prisma.LedgerEntryUncheckedCreateInput = {
        customerId,
        currency,
        direction: diff.gt(0) ? LedgerDirection.DEBIT : LedgerDirection.CREDIT,
        amount: currency === LedgerCurrency.RIAL ? new D(diff.abs().toFixed(2)) : new D(diff.abs().toFixed(4)),
        sourceType: LedgerSourceType.ADJUSTMENT,
        confirmed: true,
        confirmedAt: new Date(),
        note: 'تراز انتقالی از سیستم قدیم — مانده‌ی ذخیره‌شده در سیستم قدیم با اسناد قابل بازسازی نبود',
      };
      if (existing) await ctx.db.ledgerEntry.update({ where: { id: existing }, data });
      else {
        const created = await ctx.db.ledgerEntry.create({ data });
        await ctx.map.set('ledger', key, created.id, 'created');
      }
      ctx.report.count(S, `opening-balance adjustment (${label})`);
      ctx.report.note(S, `customer ${customerId}: ${label} adjustment ${diff.toString()} so the balance equals legacy's stored ${wanted.toFixed(4)}`);
    }

    // The cached balance = Σ every confirmed entry, the target's own and the imported ones.
    const fresh = await ctx.db.ledgerEntry.findMany({ where: { customerId, confirmed: true } });
    const total = (currency: LedgerCurrency) =>
      fresh
        .filter((e) => e.currency === currency)
        .reduce((acc, e) => (e.direction === LedgerDirection.DEBIT ? acc.add(e.amount) : acc.sub(e.amount)), new D(0));
    const before = await ctx.db.customer.findUniqueOrThrow({ where: { id: customerId }, select: { goldDebtGrams: true, fiatDebtRial: true } });
    const gold = total(LedgerCurrency.GOLD_GRAM);
    const rialSum = total(LedgerCurrency.RIAL);
    if (!before.goldDebtGrams.eq(gold) || !before.fiatDebtRial.eq(rialSum)) {
      await ctx.db.customer.update({ where: { id: customerId }, data: { goldDebtGrams: gold, fiatDebtRial: rialSum } });
      ctx.report.count(S, 'cached balance set from the ledger');
    }
  }
}

/* ───────────── favourites ───────────── */

/**
 * The wholesale app's favourites are `major_favorites` (ApiMobileController
 * :73-465, model Major\Favorite) — 3,305 rows. `fav` (251) belongs to the
 * retail storefront (Customer\FavController, guard api-singleCustomer); its
 * customer_id points at retail logins, so it is deliberately NOT read here.
 */
export async function favorites(ctx: Ctx) {
  const S = 'favorites';
  const rows = await ctx.q<Row>(
    'SELECT customer_id, product_id, MIN(created_at) AS created_at FROM major_favorites WHERE deleted_at IS NULL GROUP BY customer_id, product_id',
  );
  const data: Prisma.CustomerFavoriteCreateManyInput[] = [];
  const seen = new Set<string>();
  for (const r of rows) {
    const customerId = ctx.map.get('customer', r.customer_id);
    const productId = ctx.map.get('product', r.product_id);
    if (!customerId) { ctx.report.count(S, 'skipped: customer not migrated'); continue; }
    if (!productId) { ctx.report.count(S, 'skipped: product deleted in legacy'); continue; }
    const k = `${customerId}|${productId}`;
    if (seen.has(k)) { ctx.report.count(S, 'duplicate collapsed (merged customers)'); continue; }
    seen.add(k);
    data.push({ customerId, productId, createdAt: tehran(r.created_at) ?? undefined });
  }
  const res = await ctx.db.customerFavorite.createMany({ data, skipDuplicates: true });
  ctx.report.count(S, 'created', res.count);
  ctx.report.count(S, 'already present', data.length - res.count);
}

/* ───────────── custom orders ───────────── */

/** CustomOrder::$STS_EN (CustomOrder.php:41-47) maps one-to-one. */
const PREORDER_STATUS: Record<number, PreOrderStatus> = {
  1: PreOrderStatus.PLACED,
  2: PreOrderStatus.ADMIN_APPROVED,
  3: PreOrderStatus.WORKSHOP_APPROVED,
  4: PreOrderStatus.READY_TO_SHIP,
  5: PreOrderStatus.DELIVERED,
  6: PreOrderStatus.CANCELLED,
};

export async function preOrders(ctx: Ctx) {
  const S = 'custom orders';
  const rows = await ctx.q<Row>('SELECT * FROM custom_orders WHERE deleted_at IS NULL');
  for (const r of rows) {
    const customerId = ctx.map.get('customer', r.customer_id);
    if (!customerId) { ctx.report.count(S, 'skipped: customer not migrated'); continue; }
    const sumText = text(r.sum);
    const data = {
      customerId,
      cityId: ctx.map.get('city', r.city_id) ?? null,
      workshopId: ctx.map.get('workshop', r.workshop_id) ?? null,
      status: PREORDER_STATUS[int(r.sts) ?? 1] ?? PreOrderStatus.PLACED,
      designImageUrl: await ctx.imageUrl(r.file_id, S),
      colorName: text(r.color),
      sizeSpec: text(r.size),
      stoneColor: text(r.color_stone),
      minaColor: text(r.color_mina),
      estimatedWeightGrams: r.weight === null ? null : grams(r.weight),
      estimatedPriceRial: sumText && /^\d+(\.\d+)?$/.test(sumText) ? rial(sumText) : null,
      description: text(r.description),
    };
    const res = await upsert(ctx, 'preorder', r.id, {
      exists: async (id) => !!(await ctx.db.preOrder.findUnique({ where: { id } })),
      find: async () => null,
      create: () => ctx.db.preOrder.create({ data: { ...data, createdAt: tehran(r.created_at) ?? undefined } }),
      update: async (id) => {
        await ctx.db.preOrder.update({ where: { id }, data });
      },
    });
    ctx.report.count(S, res.isNew ? 'created' : 'updated');
  }
}