"use server";

import { revalidatePath } from "next/cache";
import { redirect } from "next/navigation";
import { authenticateUser, createSession, destroySession } from "@/lib/auth";
import { getDb } from "@/lib/db";

type ParsedLine = {
  sku: string;
  quantity: number;
  amount: number;
};

type ParsedFulfillmentLine = {
  sku: string;
  quantity: number;
};

function db() {
  return getDb();
}

function getText(formData: FormData, key: string) {
  return String(formData.get(key) ?? "").trim();
}

function getNumber(formData: FormData, key: string) {
  const value = Number(getText(formData, key));
  return Number.isFinite(value) ? value : 0;
}

function parseLines(raw: string): ParsedLine[] {
  return raw
    .split(/\r?\n/)
    .map((line) => line.trim())
    .filter(Boolean)
    .map((line) => {
      const [sku, quantity, amount] = line.split(",").map((piece) => piece.trim());
      if (!sku || !quantity || !amount) {
        throw new Error(`Invalid line format: "${line}". Use SKU,quantity,amount.`);
      }

      const parsedQuantity = Number(quantity);
      const parsedAmount = Number(amount);

      if (!Number.isFinite(parsedQuantity) || parsedQuantity <= 0 || !Number.isFinite(parsedAmount) || parsedAmount < 0) {
        throw new Error(`Invalid line values: "${line}".`);
      }

      return {
        sku,
        quantity: parsedQuantity,
        amount: parsedAmount
      };
    });
}

function parseFulfillmentLines(raw: string): ParsedFulfillmentLine[] {
  return raw
    .split(/\r?\n/)
    .map((line) => line.trim())
    .filter(Boolean)
    .map((line) => {
      const [sku, quantity] = line.split(",").map((piece) => piece.trim());

      if (!sku || !quantity) {
        throw new Error(`Invalid fulfillment line format: "${line}". Use SKU,quantity.`);
      }

      const parsedQuantity = Number(quantity);

      if (!Number.isFinite(parsedQuantity) || parsedQuantity <= 0) {
        throw new Error(`Invalid fulfillment quantity: "${line}".`);
      }

      return { sku, quantity: parsedQuantity };
    });
}

function getPartIdBySku(sku: string) {
  const row = db().prepare(`SELECT id FROM parts WHERE sku = ?`).get(sku) as { id: number } | undefined;
  if (!row) {
    throw new Error(`Part with SKU "${sku}" does not exist.`);
  }
  return row.id;
}

function getOrderNumber(prefix: string, table: "sales_orders" | "purchase_orders") {
  const row = db().prepare(`SELECT COUNT(*) AS count FROM ${table}`).get() as { count: number };
  return `${prefix}-${String((row.count ?? 0) + 1).padStart(5, "0")}`;
}

function getDocumentNumber(prefix: string, table: "customer_invoices" | "vendor_bills") {
  const row = db().prepare(`SELECT COUNT(*) AS count FROM ${table}`).get() as { count: number };
  return `${prefix}-${String((row.count ?? 0) + 1).padStart(5, "0")}`;
}

function createJournalEntry(
  entryType: string,
  referenceType: string,
  referenceId: number | null,
  description: string,
  lines: Array<{ accountCode: string; accountName: string; debit: number; credit: number }>
) {
  const tx = db().transaction(() => {
    const result = db()
      .prepare(
        `
        INSERT INTO journal_entries (entry_type, reference_type, reference_id, description)
        VALUES (?, ?, ?, ?)
        `
      )
      .run(entryType, referenceType, referenceId, description);

    const journalEntryId = Number(result.lastInsertRowid);
    const insertLine = db().prepare(
      `
      INSERT INTO journal_lines (journal_entry_id, account_code, account_name, debit, credit)
      VALUES (?, ?, ?, ?, ?)
      `
    );

    for (const line of lines) {
      insertLine.run(journalEntryId, line.accountCode, line.accountName, line.debit, line.credit);
    }
  });

  tx();
}

function resolveAccount(code: string) {
  const row = db().prepare(`SELECT code, name FROM accounts WHERE code = ?`).get(code) as { code: string; name: string } | undefined;

  if (!row) {
    throw new Error(`Account "${code}" does not exist.`);
  }

  return row;
}

function parseJournalLines(raw: string) {
  return raw
    .split(/\r?\n/)
    .map((line) => line.trim())
    .filter(Boolean)
    .map((line) => {
      const [accountCode, debit, credit] = line.split(",").map((piece) => piece.trim());

      if (!accountCode || debit === undefined || credit === undefined) {
        throw new Error(`Invalid journal line format: "${line}". Use account code,debit,credit.`);
      }

      const parsedDebit = Number(debit);
      const parsedCredit = Number(credit);

      if (!Number.isFinite(parsedDebit) || !Number.isFinite(parsedCredit) || parsedDebit < 0 || parsedCredit < 0) {
        throw new Error(`Invalid journal amounts: "${line}".`);
      }

      if ((parsedDebit === 0 && parsedCredit === 0) || (parsedDebit > 0 && parsedCredit > 0)) {
        throw new Error(`Journal lines must have either a debit or a credit: "${line}".`);
      }

      const account = resolveAccount(accountCode);

      return {
        accountCode: account.code,
        accountName: account.name,
        debit: parsedDebit,
        credit: parsedCredit
      };
    });
}

export async function createPart(formData: FormData) {
  db()
    .prepare(
      `
      INSERT INTO parts (sku, name, description, kind, unit_cost, sale_price, reorder_point, unit_of_measure)
      VALUES (?, ?, ?, ?, ?, ?, ?, ?)
      `
    )
    .run(
      getText(formData, "sku"),
      getText(formData, "name"),
      getText(formData, "description"),
      getText(formData, "kind"),
      getNumber(formData, "unitCost"),
      getNumber(formData, "salePrice"),
      getNumber(formData, "reorderPoint"),
      getText(formData, "unitOfMeasure") || "ea"
    );

  revalidatePath("/");
  revalidatePath("/parts");
  revalidatePath("/assemblies");
}

export async function addKitComponent(formData: FormData) {
  const assemblyId = getPartIdBySku(getText(formData, "assemblySku"));
  const componentId = getPartIdBySku(getText(formData, "componentSku"));

  db()
    .prepare(
      `
      INSERT INTO kit_components (assembly_part_id, component_part_id, quantity)
      VALUES (?, ?, ?)
      ON CONFLICT (assembly_part_id, component_part_id)
      DO UPDATE SET quantity = excluded.quantity
      `
    )
    .run(assemblyId, componentId, getNumber(formData, "quantity"));

  revalidatePath("/assemblies");
}

export async function buildAssembly(formData: FormData) {
  const assemblySku = getText(formData, "assemblySku");
  const buildQuantity = getNumber(formData, "quantity");

  if (buildQuantity <= 0) {
    throw new Error("Build quantity must be greater than zero.");
  }

  const assemblyId = getPartIdBySku(assemblySku);

  const components = db()
    .prepare(
      `
      SELECT
        kc.component_part_id AS componentId,
        kc.quantity AS componentQuantity,
        p.sku,
        p.unit_cost AS unitCost,
        COALESCE(ib.quantity_on_hand, 0) AS quantityOnHand
      FROM kit_components kc
      INNER JOIN parts p ON p.id = kc.component_part_id
      LEFT JOIN inventory_balances ib ON ib.part_id = p.id
      WHERE kc.assembly_part_id = ?
      `
    )
    .all(assemblyId) as Array<{
      componentId: number;
      componentQuantity: number;
      sku: string;
      unitCost: number;
      quantityOnHand: number;
    }>;

  if (components.length === 0) {
    throw new Error("Assembly has no bill of materials defined.");
  }

  for (const component of components) {
    const needed = component.componentQuantity * buildQuantity;
    if (component.quantityOnHand < needed) {
      throw new Error(`Not enough stock for component ${component.sku}. Need ${needed}, have ${component.quantityOnHand}.`);
    }
  }

  const buildCost = components.reduce((sum, component) => sum + component.unitCost * component.componentQuantity, 0);

  const tx = db().transaction(() => {
    const insertInventory = db().prepare(
      `
      INSERT INTO inventory_transactions (part_id, quantity_delta, unit_cost, transaction_type, reference_type, reference_id, notes)
      VALUES (?, ?, ?, ?, ?, ?, ?)
      `
    );
    const updateAssemblyCost = db().prepare(`UPDATE parts SET unit_cost = ? WHERE id = ?`);

    for (const component of components) {
      insertInventory.run(
        component.componentId,
        component.componentQuantity * buildQuantity * -1,
        component.unitCost,
        "assembly_consume",
        "assembly_build",
        assemblyId,
        `Consumed for ${assemblySku}`
      );
    }

    insertInventory.run(
      assemblyId,
      buildQuantity,
      buildCost,
      "assembly_build",
      "assembly_build",
      assemblyId,
      `Built ${buildQuantity} of ${assemblySku}`
    );

    updateAssemblyCost.run(buildCost, assemblyId);
  });

  tx();
  revalidatePath("/");
  revalidatePath("/parts");
  revalidatePath("/assemblies");
}

export async function recordAdjustment(formData: FormData) {
  const partId = getPartIdBySku(getText(formData, "sku"));
  const quantityDelta = getNumber(formData, "quantityDelta");
  const unitCost = getNumber(formData, "unitCost");
  const notes = getText(formData, "notes");
  const inventoryImpact = Math.abs(quantityDelta * unitCost);

  db()
    .prepare(
      `
      INSERT INTO inventory_transactions (part_id, quantity_delta, unit_cost, transaction_type, reference_type, notes)
      VALUES (?, ?, ?, 'adjustment', 'manual_adjustment', ?)
      `
    )
    .run(partId, quantityDelta, unitCost, notes);

  if (inventoryImpact > 0) {
    createJournalEntry("adjustment", "manual_adjustment", partId, notes || "Inventory adjustment posted", [
      {
        accountCode: quantityDelta >= 0 ? "1200" : "6100",
        accountName: quantityDelta >= 0 ? "Inventory" : "Inventory Adjustments",
        debit: quantityDelta >= 0 ? inventoryImpact : 0,
        credit: quantityDelta >= 0 ? 0 : inventoryImpact
      },
      {
        accountCode: quantityDelta >= 0 ? "3000" : "1200",
        accountName: quantityDelta >= 0 ? "Owner Equity" : "Inventory",
        debit: quantityDelta >= 0 ? 0 : inventoryImpact,
        credit: quantityDelta >= 0 ? inventoryImpact : 0
      }
    ]);
  }

  revalidatePath("/");
  revalidatePath("/parts");
  revalidatePath("/accounting");
}

export async function createCustomer(formData: FormData) {
  db()
    .prepare(
      `
      INSERT INTO customers (code, name, email, phone, billing_address, shipping_address)
      VALUES (?, ?, ?, ?, ?, ?)
      `
    )
    .run(
      getText(formData, "code"),
      getText(formData, "name"),
      getText(formData, "email"),
      getText(formData, "phone"),
      getText(formData, "billingAddress"),
      getText(formData, "shippingAddress")
    );

  revalidatePath("/customers");
  revalidatePath("/");
}

export async function createAccount(formData: FormData) {
  const category = getText(formData, "category");

  if (!["asset", "liability", "equity", "revenue", "expense"].includes(category)) {
    throw new Error("Invalid account category.");
  }

  db()
    .prepare(
      `
      INSERT INTO accounts (code, name, category, is_system)
      VALUES (?, ?, ?, 0)
      `
    )
    .run(getText(formData, "code"), getText(formData, "name"), category);

  revalidatePath("/accounting");
}

export async function createVendor(formData: FormData) {
  db()
    .prepare(
      `
      INSERT INTO vendors (code, name, email, phone, address)
      VALUES (?, ?, ?, ?, ?)
      `
    )
    .run(
      getText(formData, "code"),
      getText(formData, "name"),
      getText(formData, "email"),
      getText(formData, "phone"),
      getText(formData, "address")
    );

  revalidatePath("/vendors");
  revalidatePath("/");
}

export async function createSalesOrder(formData: FormData) {
  const customerCode = getText(formData, "customerCode");
  const lines = parseLines(getText(formData, "lines"));
  const customerRow = db().prepare(`SELECT id FROM customers WHERE code = ?`).get(customerCode) as { id: number } | undefined;

  if (!customerRow) {
    throw new Error(`Customer "${customerCode}" does not exist.`);
  }

  const tx = db().transaction(() => {
    const result = db()
      .prepare(
        `
        INSERT INTO sales_orders (order_number, customer_id, status, notes)
        VALUES (?, ?, 'open', ?)
        `
      )
      .run(getOrderNumber("SO", "sales_orders"), customerRow.id, getText(formData, "notes"));

    const orderId = Number(result.lastInsertRowid);
    const insertLine = db().prepare(
      `
      INSERT INTO sales_order_lines (sales_order_id, part_id, quantity, unit_price)
      VALUES (?, ?, ?, ?)
      `
    );

    for (const line of lines) {
      insertLine.run(orderId, getPartIdBySku(line.sku), line.quantity, line.amount);
    }
  });

  tx();
  revalidatePath("/");
  revalidatePath("/sales-orders");
}

export async function shipSalesOrder(formData: FormData) {
  const orderId = Number(getText(formData, "orderId"));
  const order = db()
    .prepare(`SELECT customer_id AS customerId, status FROM sales_orders WHERE id = ?`)
    .get(orderId) as { customerId: number; status: string } | undefined;

  if (!order) {
    throw new Error("Sales order not found.");
  }

  if (order.status === "shipped") {
    throw new Error("Sales order has already been shipped.");
  }

  const orderLines = db()
    .prepare(
      `
      SELECT
        sol.id AS lineId,
        so.order_number AS orderNumber,
        p.id AS partId,
        p.sku,
        p.unit_cost AS unitCost,
        sol.quantity,
        sol.shipped_quantity AS shippedQuantity,
        sol.unit_price AS unitPrice,
        COALESCE(ib.quantity_on_hand, 0) AS quantityOnHand
      FROM sales_order_lines sol
      INNER JOIN sales_orders so ON so.id = sol.sales_order_id
      INNER JOIN parts p ON p.id = sol.part_id
      LEFT JOIN inventory_balances ib ON ib.part_id = p.id
      WHERE sol.sales_order_id = ?
      `
    )
    .all(orderId) as Array<{
      lineId: number;
      orderNumber: string;
      partId: number;
      sku: string;
      unitCost: number;
      quantity: number;
      shippedQuantity: number;
      unitPrice: number;
      quantityOnHand: number;
    }>;

  if (orderLines.length === 0) {
    throw new Error("Sales order has no lines.");
  }

  const requestedLines = parseFulfillmentLines(getText(formData, "lines"));
  const fulfilledLines = requestedLines.length
    ? requestedLines.map((request) => {
        const matchingLine = orderLines.find((line) => line.sku === request.sku);

        if (!matchingLine) {
          throw new Error(`SKU ${request.sku} is not on this sales order.`);
        }

        const remaining = matchingLine.quantity - matchingLine.shippedQuantity;
        if (request.quantity > remaining) {
          throw new Error(`Cannot ship ${request.quantity} of ${request.sku}; only ${remaining} remain.`);
        }

        if (matchingLine.quantityOnHand < request.quantity) {
          throw new Error(`Insufficient stock for ${matchingLine.sku}. Need ${request.quantity}, have ${matchingLine.quantityOnHand}.`);
        }

        return { ...matchingLine, shipQuantity: request.quantity };
      })
    : orderLines
        .map((line) => {
          const remaining = line.quantity - line.shippedQuantity;
          return remaining > 0 ? { ...line, shipQuantity: remaining } : null;
        })
        .filter((line): line is NonNullable<typeof line> => line !== null);

  if (fulfilledLines.length === 0) {
    throw new Error("No shippable quantities were provided.");
  }

  const revenue = fulfilledLines.reduce((sum, line) => sum + line.shipQuantity * line.unitPrice, 0);
  const cogs = fulfilledLines.reduce((sum, line) => sum + line.shipQuantity * line.unitCost, 0);
  const orderNumber = orderLines[0].orderNumber;

  const tx = db().transaction(() => {
    const insertInventory = db().prepare(
      `
      INSERT INTO inventory_transactions (part_id, quantity_delta, unit_cost, transaction_type, reference_type, reference_id, notes)
      VALUES (?, ?, ?, 'sales_shipment', 'sales_order', ?, ?)
      `
    );
    const updateLine = db().prepare(`UPDATE sales_order_lines SET shipped_quantity = shipped_quantity + ? WHERE id = ?`);

    for (const line of fulfilledLines) {
      insertInventory.run(line.partId, line.shipQuantity * -1, line.unitCost, orderId, `Shipment for ${orderNumber}`);
      updateLine.run(line.shipQuantity, line.lineId);
    }

    const remainingCount = db()
      .prepare(`SELECT COUNT(*) AS count FROM sales_order_lines WHERE sales_order_id = ? AND shipped_quantity < quantity`)
      .get(orderId) as { count: number };
    const nextStatus = remainingCount.count > 0 ? "partial" : "shipped";

    db().prepare(`UPDATE sales_orders SET status = ?, shipped_at = CURRENT_TIMESTAMP WHERE id = ?`).run(nextStatus, orderId);
    db()
      .prepare(
        `
        INSERT INTO customer_invoices (invoice_number, sales_order_id, customer_id, status, due_date, total_amount, paid_amount)
        VALUES (?, ?, ?, 'open', DATE('now', '+30 day'), ?, 0)
        `
      )
      .run(getDocumentNumber("INV", "customer_invoices"), orderId, order.customerId, revenue);
  });

  tx();

  createJournalEntry("shipment", "sales_order", orderId, `Shipment posted for ${orderNumber}`, [
    { accountCode: "1100", accountName: "Accounts Receivable", debit: revenue, credit: 0 },
    { accountCode: "4000", accountName: "Sales Revenue", debit: 0, credit: revenue },
    { accountCode: "5000", accountName: "Cost of Goods Sold", debit: cogs, credit: 0 },
    { accountCode: "1200", accountName: "Inventory", debit: 0, credit: cogs }
  ]);

  revalidatePath("/");
  revalidatePath("/parts");
  revalidatePath("/sales-orders");
  revalidatePath("/accounting");
  revalidatePath("/invoices");
}

export async function createPurchaseOrder(formData: FormData) {
  const vendorCode = getText(formData, "vendorCode");
  const lines = parseLines(getText(formData, "lines"));
  const vendorRow = db().prepare(`SELECT id FROM vendors WHERE code = ?`).get(vendorCode) as { id: number } | undefined;

  if (!vendorRow) {
    throw new Error(`Vendor "${vendorCode}" does not exist.`);
  }

  const tx = db().transaction(() => {
    const result = db()
      .prepare(
        `
        INSERT INTO purchase_orders (order_number, vendor_id, status, notes)
        VALUES (?, ?, 'ordered', ?)
        `
      )
      .run(getOrderNumber("PO", "purchase_orders"), vendorRow.id, getText(formData, "notes"));

    const orderId = Number(result.lastInsertRowid);
    const insertLine = db().prepare(
      `
      INSERT INTO purchase_order_lines (purchase_order_id, part_id, quantity, unit_cost)
      VALUES (?, ?, ?, ?)
      `
    );

    for (const line of lines) {
      insertLine.run(orderId, getPartIdBySku(line.sku), line.quantity, line.amount);
    }
  });

  tx();
  revalidatePath("/");
  revalidatePath("/purchase-orders");
}

export async function receivePurchaseOrder(formData: FormData) {
  const orderId = Number(getText(formData, "orderId"));
  const order = db()
    .prepare(`SELECT vendor_id AS vendorId, status FROM purchase_orders WHERE id = ?`)
    .get(orderId) as { vendorId: number; status: string } | undefined;

  if (!order) {
    throw new Error("Purchase order not found.");
  }

  if (order.status === "received") {
    throw new Error("Purchase order has already been received.");
  }

  const lines = db()
    .prepare(
      `
      SELECT
        pol.id AS lineId,
        po.order_number AS orderNumber,
        pol.part_id AS partId,
        pol.quantity,
        pol.received_quantity AS receivedQuantity,
        p.sku,
        pol.unit_cost AS unitCost
      FROM purchase_order_lines pol
      INNER JOIN purchase_orders po ON po.id = pol.purchase_order_id
      INNER JOIN parts p ON p.id = pol.part_id
      WHERE pol.purchase_order_id = ?
      `
    )
    .all(orderId) as Array<{
      lineId: number;
      orderNumber: string;
      partId: number;
      quantity: number;
      receivedQuantity: number;
      sku: string;
      unitCost: number;
    }>;

  if (lines.length === 0) {
    throw new Error("Purchase order has no lines.");
  }

  const requestedLines = parseFulfillmentLines(getText(formData, "lines"));
  const fulfilledLines = requestedLines.length
    ? requestedLines.map((request) => {
        const matchingLine = lines.find((line) => line.sku === request.sku);

        if (!matchingLine) {
          throw new Error(`SKU ${request.sku} is not on this purchase order.`);
        }

        const remaining = matchingLine.quantity - matchingLine.receivedQuantity;
        if (request.quantity > remaining) {
          throw new Error(`Cannot receive ${request.quantity} of ${request.sku}; only ${remaining} remain.`);
        }

        return { ...matchingLine, receiveQuantity: request.quantity };
      })
    : lines
        .map((line) => {
          const remaining = line.quantity - line.receivedQuantity;
          return remaining > 0 ? { ...line, receiveQuantity: remaining } : null;
        })
        .filter((line): line is NonNullable<typeof line> => line !== null);

  if (fulfilledLines.length === 0) {
    throw new Error("No receivable quantities were provided.");
  }

  const receiptValue = fulfilledLines.reduce((sum, line) => sum + line.receiveQuantity * line.unitCost, 0);
  const orderNumber = lines[0].orderNumber;

  const tx = db().transaction(() => {
    const insertInventory = db().prepare(
      `
      INSERT INTO inventory_transactions (part_id, quantity_delta, unit_cost, transaction_type, reference_type, reference_id, notes)
      VALUES (?, ?, ?, 'purchase_receipt', 'purchase_order', ?, ?)
      `
    );

    const updatePartCost = db().prepare(`UPDATE parts SET unit_cost = ? WHERE id = ?`);
    const updateLine = db().prepare(`UPDATE purchase_order_lines SET received_quantity = received_quantity + ? WHERE id = ?`);

    for (const line of fulfilledLines) {
      insertInventory.run(line.partId, line.receiveQuantity, line.unitCost, orderId, `Receipt for ${orderNumber}`);
      updatePartCost.run(line.unitCost, line.partId);
      updateLine.run(line.receiveQuantity, line.lineId);
    }

    const remainingCount = db()
      .prepare(`SELECT COUNT(*) AS count FROM purchase_order_lines WHERE purchase_order_id = ? AND received_quantity < quantity`)
      .get(orderId) as { count: number };
    const nextStatus = remainingCount.count > 0 ? "partial" : "received";

    db().prepare(`UPDATE purchase_orders SET status = ?, received_at = CURRENT_TIMESTAMP WHERE id = ?`).run(nextStatus, orderId);
    db()
      .prepare(
        `
        INSERT INTO vendor_bills (bill_number, purchase_order_id, vendor_id, status, due_date, total_amount, paid_amount)
        VALUES (?, ?, ?, 'open', DATE('now', '+30 day'), ?, 0)
        `
      )
      .run(getDocumentNumber("BILL", "vendor_bills"), orderId, order.vendorId, receiptValue);
  });

  tx();

  createJournalEntry("receipt", "purchase_order", orderId, `Receipt posted for ${orderNumber}`, [
    { accountCode: "1200", accountName: "Inventory", debit: receiptValue, credit: 0 },
    { accountCode: "2000", accountName: "Accounts Payable", debit: 0, credit: receiptValue }
  ]);

  revalidatePath("/");
  revalidatePath("/parts");
  revalidatePath("/purchase-orders");
  revalidatePath("/accounting");
  revalidatePath("/vendor-bills");
}

export async function createManualJournalEntry(formData: FormData) {
  const description = getText(formData, "description");
  const lines = parseJournalLines(getText(formData, "lines"));
  const debitTotal = lines.reduce((sum, line) => sum + line.debit, 0);
  const creditTotal = lines.reduce((sum, line) => sum + line.credit, 0);

  if (Math.abs(debitTotal - creditTotal) > 0.005) {
    throw new Error("Manual journal entry is not balanced.");
  }

  createJournalEntry("manual", "manual_journal", null, description || "Manual journal entry", lines);

  revalidatePath("/accounting");
}

export async function loginAction(formData: FormData) {
  const email = getText(formData, "email");
  const password = getText(formData, "password");
  const user = authenticateUser(db(), email, password);

  if (!user) {
    throw new Error("Invalid email or password.");
  }

  await createSession(user);
  redirect("/");
}

export async function logoutAction() {
  await destroySession();
  redirect("/login");
}

export async function receiveCustomerPayment(formData: FormData) {
  const invoiceId = Number(getText(formData, "invoiceId"));
  const amount = getNumber(formData, "amount");
  const notes = getText(formData, "notes");

  if (amount <= 0) {
    throw new Error("Payment amount must be greater than zero.");
  }

  const invoice = db()
    .prepare(
      `
      SELECT id, invoice_number AS invoiceNumber, total_amount AS totalAmount, paid_amount AS paidAmount
      FROM customer_invoices
      WHERE id = ?
      `
    )
    .get(invoiceId) as { id: number; invoiceNumber: string; totalAmount: number; paidAmount: number } | undefined;

  if (!invoice) {
    throw new Error("Invoice not found.");
  }

  const balanceDue = invoice.totalAmount - invoice.paidAmount;

  if (amount > balanceDue) {
    throw new Error("Payment cannot exceed invoice balance.");
  }

  const newPaidAmount = invoice.paidAmount + amount;
  const newStatus = Math.abs(newPaidAmount - invoice.totalAmount) <= 0.005 ? "paid" : "partial";

  const tx = db().transaction(() => {
    db()
      .prepare(`INSERT INTO customer_payments (invoice_id, amount, notes) VALUES (?, ?, ?)`)
      .run(invoiceId, amount, notes);
    db()
      .prepare(`UPDATE customer_invoices SET paid_amount = ?, status = ? WHERE id = ?`)
      .run(newPaidAmount, newStatus, invoiceId);
  });

  tx();

  createJournalEntry("customer_payment", "customer_invoice", invoiceId, `Payment received for ${invoice.invoiceNumber}`, [
    { accountCode: "1000", accountName: "Cash", debit: amount, credit: 0 },
    { accountCode: "1100", accountName: "Accounts Receivable", debit: 0, credit: amount }
  ]);

  revalidatePath("/");
  revalidatePath("/accounting");
  revalidatePath("/invoices");
}

export async function payVendorBill(formData: FormData) {
  const vendorBillId = Number(getText(formData, "vendorBillId"));
  const amount = getNumber(formData, "amount");
  const notes = getText(formData, "notes");

  if (amount <= 0) {
    throw new Error("Payment amount must be greater than zero.");
  }

  const bill = db()
    .prepare(
      `
      SELECT id, bill_number AS billNumber, total_amount AS totalAmount, paid_amount AS paidAmount
      FROM vendor_bills
      WHERE id = ?
      `
    )
    .get(vendorBillId) as { id: number; billNumber: string; totalAmount: number; paidAmount: number } | undefined;

  if (!bill) {
    throw new Error("Vendor bill not found.");
  }

  const balanceDue = bill.totalAmount - bill.paidAmount;

  if (amount > balanceDue) {
    throw new Error("Payment cannot exceed vendor bill balance.");
  }

  const newPaidAmount = bill.paidAmount + amount;
  const newStatus = Math.abs(newPaidAmount - bill.totalAmount) <= 0.005 ? "paid" : "partial";

  const tx = db().transaction(() => {
    db()
      .prepare(`INSERT INTO vendor_payments (vendor_bill_id, amount, notes) VALUES (?, ?, ?)`)
      .run(vendorBillId, amount, notes);
    db()
      .prepare(`UPDATE vendor_bills SET paid_amount = ?, status = ? WHERE id = ?`)
      .run(newPaidAmount, newStatus, vendorBillId);
  });

  tx();

  createJournalEntry("vendor_payment", "vendor_bill", vendorBillId, `Vendor payment posted for ${bill.billNumber}`, [
    { accountCode: "2000", accountName: "Accounts Payable", debit: amount, credit: 0 },
    { accountCode: "1000", accountName: "Cash", debit: 0, credit: amount }
  ]);

  revalidatePath("/");
  revalidatePath("/accounting");
  revalidatePath("/vendor-bills");
}