import { ok, err, type CommandContext } from "@tailor-platform/erp-kit/core";
import { Decimal } from "decimal.js";
import { accountPayableDocumentLifecycle } from "../db/accountPayableDocument.lifecycle.generated";
import type { Transaction } from "../generated/kysely-tailordb";
import { postAcquisitionCostAdjustment } from "../internal/acquisitionCostAdjustment";
import {
  AccountInactiveError,
  AccountNotFoundError,
  ApAccountingPeriodNotFoundError,
  ApDocumentHasActiveHoldError,
  ApDocumentNotFoundError,
  ApInvalidDocumentStatusError,
  ApLineTotalMismatchError,
  ApMinimumLinesNotMetError,
  ApJournalEntryCreateFailedError,
  ApJournalEntryPostFailedError,
  ApPostingCurrencyMismatchError,
  CompanyNotFoundError,
} from "../lib/errors.generated";
import type {
  CoaManagementQueries,
  FinancialAccountingCommands,
  FinancialAccountingQueries,
  InventoryCommands,
  OrganizationQueries,
  PurchaseQueries,
} from "../module";

export interface PostAccountPayableDocumentInput {
  id: string;
}

function validateLineTotal(
  identifier: string,
  totalAmount: string,
  lines: { grossAmount: string }[],
) {
  if (lines.length === 0) return err(new ApMinimumLinesNotMetError(identifier));
  const lineTotal = lines.reduce((sum, line) => sum.plus(line.grossAmount), new Decimal(0));
  if (!lineTotal.eq(new Decimal(totalAmount))) {
    return err(new ApLineTotalMismatchError(identifier));
  }
  return ok({});
}

function validateDistributionTotal(
  identifier: string,
  totalAmount: string,
  distributions: { amount: string }[],
) {
  if (distributions.length === 0) return err(new ApMinimumLinesNotMetError(identifier));
  const distributionTotal = distributions.reduce(
    (sum, distribution) => sum.plus(distribution.amount),
    new Decimal(0),
  );
  if (!distributionTotal.eq(new Decimal(totalAmount))) {
    return err(new ApLineTotalMismatchError(identifier));
  }
  return ok({});
}

export async function run(
  db: Transaction,
  input: PostAccountPayableDocumentInput,
  ctx: CommandContext,
  organizationQueries: Pick<OrganizationQueries, "getCompany">,
  financialAccountingCommands: Pick<
    FinancialAccountingCommands,
    "createJournalEntry" | "postJournalEntry"
  >,
  financialAccountingQueries: Pick<FinancialAccountingQueries, "getPeriodByDate">,
  coaManagementQueries: Pick<CoaManagementQueries, "listAccounts">,
  purchaseQueries: Pick<PurchaseQueries, "listPurchaseOrderLinesForMatching">,
  inventoryCommands: Pick<InventoryCommands, "postAcquisitionCostAdjustment">,
) {
  const document = await db
    .selectFrom("AccountPayableDocument")
    .selectAll()
    .where("id", "=", input.id)
    .forUpdate()
    .executeTakeFirst();
  if (!document) return err(new ApDocumentNotFoundError(input.id));

  const nextStatus = accountPayableDocumentLifecycle.tryTransition(document.status, "post");
  if (!nextStatus) return err(new ApInvalidDocumentStatusError(input.id));

  const { company } = (await organizationQueries.getCompany(db, { id: document.companyId }, ctx))
    .value;
  if (!company) return err(new CompanyNotFoundError(document.companyId));
  if (document.currencyId !== company.baseCurrencyId) {
    return err(new ApPostingCurrencyMismatchError(input.id));
  }

  const documentLines = await db
    .selectFrom("AccountPayableDocumentLine")
    .selectAll()
    .where("accountPayableDocumentId", "=", input.id)
    .orderBy("createdAt", "asc")
    .execute();

  const lineTotalResult = validateLineTotal(input.id, document.totalAmount, documentLines);
  if (!lineTotalResult.ok) return lineTotalResult;

  const activeHolds = await db
    .selectFrom("AccountPayableDocumentHold")
    .selectAll()
    .where("accountPayableDocumentId", "=", input.id)
    .where("releasedAt", "is", null)
    .execute();
  if (activeHolds.length > 0) return err(new ApDocumentHasActiveHoldError(input.id));

  const distributions = await db
    .selectFrom("AccountPayableDistributionLine as distribution")
    .innerJoin(
      "AccountPayableDocumentLine as line",
      "line.id",
      "distribution.accountPayableDocumentLineId",
    )
    .selectAll("distribution")
    .where("line.accountPayableDocumentId", "=", input.id)
    .orderBy("line.createdAt", "asc")
    .orderBy("distribution.createdAt", "asc")
    .execute();

  const distributionTotalResult = validateDistributionTotal(
    input.id,
    document.totalAmount,
    distributions,
  );
  if (!distributionTotalResult.ok) return distributionTotalResult;

  const distributionsByLineId = new Map<string, { amount: string }[]>();
  for (const distribution of distributions) {
    const lineDistributions = distributionsByLineId.get(distribution.accountPayableDocumentLineId);
    if (lineDistributions) lineDistributions.push(distribution);
    else distributionsByLineId.set(distribution.accountPayableDocumentLineId, [distribution]);
  }

  for (const line of documentLines) {
    const lineDistributionTotalResult = validateDistributionTotal(
      line.id,
      line.grossAmount,
      distributionsByLineId.get(line.id) ?? [],
    );
    if (!lineDistributionTotalResult.ok) return lineDistributionTotalResult;
  }

  const accountIds = [
    ...new Set([
      document.payableControlAccountId,
      ...distributions.map((distribution) => distribution.accountId),
    ]),
  ];
  const accounts = (
    await coaManagementQueries.listAccounts(
      db,
      { companyId: document.companyId, accountIds, limit: accountIds.length },
      ctx,
    )
  ).value.items;
  const accountById = new Map(accounts.map((account) => [account.id, account]));
  for (const accountId of accountIds) {
    const account = accountById.get(accountId);
    if (!account) return err(new AccountNotFoundError(accountId));
    if (account.status !== "ACTIVE") return err(new AccountInactiveError(accountId));
  }

  const { accountingPeriod } = (
    await financialAccountingQueries.getPeriodByDate(
      db,
      { companyId: document.companyId, date: document.postingDate },
      ctx,
    )
  ).value;
  if (!accountingPeriod) {
    return err(
      new ApAccountingPeriodNotFoundError(
        `${document.companyId}:${document.postingDate.toISOString()}`,
      ),
    );
  }

  const isInvoice = document.documentType === "INVOICE";
  const createResult = await financialAccountingCommands.createJournalEntry(
    db,
    {
      header: {
        companyId: document.companyId,
        accountingPeriodId: accountingPeriod.id,
        entryDate: document.postingDate,
        description: `${document.documentType} ${document.documentNumber}`,
        sourceDocumentType: "ACCOUNT_PAYABLE_DOCUMENT",
        sourceDocumentId: document.id,
      },
      lines: [
        // A negative derived amount (invoice price variance billed below the
        // order price) flips to the opposite side.
        ...distributions.map((distribution) => {
          const amount = new Decimal(distribution.amount);
          const debit = isInvoice === !amount.isNegative();
          return {
            accountId: distribution.accountId,
            debitAmount: debit ? amount.abs().toString() : null,
            creditAmount: debit ? null : amount.abs().toString(),
            description: distribution.description,
          };
        }),
        {
          accountId: document.payableControlAccountId,
          debitAmount: isInvoice ? null : document.totalAmount,
          creditAmount: isInvoice ? document.totalAmount : null,
          description: "Accounts payable control",
        },
      ],
    },
    ctx,
  );
  if (!createResult.ok) return err(new ApJournalEntryCreateFailedError(input.id));

  const postResult = await financialAccountingCommands.postJournalEntry(
    db,
    { id: createResult.value.journalEntry.id },
    ctx,
  );
  if (!postResult.ok) return err(new ApJournalEntryPostFailedError(input.id));

  const adjustmentResult = await postAcquisitionCostAdjustment(
    db,
    { document, lines: documentLines },
    ctx,
    purchaseQueries,
    inventoryCommands,
  );
  if (!adjustmentResult.ok) return adjustmentResult;

  const now = new Date();
  const postedDocument = await db
    .updateTable("AccountPayableDocument")
    .set({
      status: nextStatus,
      postedAt: now,
    })
    .where("id", "=", input.id)
    .returningAll()
    .executeTakeFirstOrThrow();

  return ok({
    accountPayableDocument: postedDocument,
    journalEntry: postResult.value.journalEntry,
  });
}