import { useCallback, useState } from "react";
import { VendorPortalFeedback } from "@/app/v/_components/vendor-portal-feedback";
import { vendorPortalApi } from "@/domain/vendor-portal/api/vendor-portal-api";
import { createUpliftRequestKey } from "@/domain/vendor-portal/lib/request-key";
import type {
  VendorPortalDocumentStatus,
  VendorPortalUpliftRequest,
} from "@/domain/vendor-portal/types/vendor-portal";
import { UpliftRequestForm } from "@/app/v/[token]/dispatch/_components/uplift-request-form";
import type { UpliftFormValues } from "@/domain/vendor-portal/lib/uplift-validation";
import { UpliftRequestCard } from "@/app/v/[token]/dispatch/_components/uplift-request-card";
import {
  useVendorUpliftEvidence,
  type EvidenceScanState,
} from "@/app/v/[token]/dispatch/_components/use-uplift-evidence";

const ACTIVE_STATUSES = new Set(["Pending", "ChangesRequested"]);

type UpliftRequestsSectionProps = {
  token: string;
  dispatchId: number;
  currentNte?: number;
  upliftRequests: VendorPortalUpliftRequest[];
  locked: boolean;
  onChanged: () => Promise<void>;
  pollDocument: (documentId: number) => Promise<VendorPortalDocumentStatus | undefined>;
};

type UseVendorUpliftActionsArgs = {
  token: string;
  dispatchId: number;
  currentNte?: number;
  onChanged: () => Promise<void>;
  evidence: ReturnType<typeof useVendorUpliftEvidence>;
};

function scanErrorMessage(scan: EvidenceScanState): string {
  if (scan === "Rejected") {
    return "The evidence file was rejected by the security scan.";
  }
  return "Security scan timed out. Please try again once the file finishes scanning.";
}

function useVendorUpliftActions({
  token,
  dispatchId,
  currentNte,
  onChanged,
  evidence,
}: UseVendorUpliftActionsArgs) {
  const [submitting, setSubmitting] = useState(false);
  const [formError, setFormError] = useState("");
  const [infoMessage, setInfoMessage] = useState("");
  const [requestError, setRequestError] = useState("");
  const [errorRequestId, setErrorRequestId] = useState<string | number | null>(null);

  const uploadAndScan = useCallback(
    async (file: File): Promise<{ documentId: number; scan: EvidenceScanState }> => {
      const document = await evidence.uploadEvidence({ token, dispatchId, file });
      const scan = await evidence.waitForScan(document.id);
      evidence.setScanState(scan);
      return { documentId: document.id, scan };
    },
    [evidence, token, dispatchId],
  );

  const handleCreate = async (values: UpliftFormValues) => {
    setFormError("");
    setInfoMessage("");
    setSubmitting(true);
    try {
      const requiresApproval = currentNte == null || values.amount > (currentNte ?? 0);
      let evidenceDocumentId: number | undefined;
      if (requiresApproval) {
        if (!values.evidenceFile) {
          setFormError(
            "Attach PDF, JPG, or PNG evidence — approval-required requests need evidence.",
          );
          return;
        }
        const result = await uploadAndScan(values.evidenceFile);
        if (result.scan !== "Passed") {
          setFormError(scanErrorMessage(result.scan));
          return;
        }
        evidenceDocumentId = result.documentId;
      }
      const outcome = await vendorPortalApi.requestUplift(token, dispatchId, {
        requestedNTE: values.amount,
        reason: values.reason,
        requestKey: createUpliftRequestKey(),
        evidenceDocumentId,
      });
      evidence.reset();
      await onChanged();
      if (outcome.outcome === "NoApprovalRequired") {
        setInfoMessage("No approval required — the existing NTE already covers this amount.");
      }
    } catch {
      setFormError("Unable to request the NTE uplift. Please try again.");
    } finally {
      setSubmitting(false);
    }
  };

  const handleWithdraw = async (request: VendorPortalUpliftRequest) => {
    if (!window.confirm("Withdraw this uplift request?")) return;
    setErrorRequestId(request.id);
    setRequestError("");
    setSubmitting(true);
    try {
      await vendorPortalApi.withdrawUplift(token, dispatchId, request.id);
      await onChanged();
    } catch {
      setRequestError("Unable to withdraw the uplift request. Please try again.");
    } finally {
      setSubmitting(false);
    }
  };

  const handleRevise = async (request: VendorPortalUpliftRequest, values: UpliftFormValues) => {
    setErrorRequestId(request.id);
    setRequestError("");
    setSubmitting(true);
    try {
      const requiresApproval =
        request.currentNTE == null || values.amount > (request.currentNTE ?? 0);
      let evidenceDocumentId = request.evidenceDocumentId;
      if (requiresApproval && values.evidenceFile) {
        const result = await uploadAndScan(values.evidenceFile);
        if (result.scan !== "Passed") {
          setRequestError(scanErrorMessage(result.scan));
          return;
        }
        evidenceDocumentId = result.documentId;
      }
      await vendorPortalApi.reviseUplift(token, dispatchId, request.id, {
        requestedNTE: values.amount,
        reason: values.reason,
        evidenceDocumentId,
      });
      evidence.reset();
      await onChanged();
    } catch {
      setRequestError("Unable to revise the uplift request. Please try again.");
    } finally {
      setSubmitting(false);
    }
  };

  return {
    submitting,
    formError,
    infoMessage,
    requestError,
    errorRequestId,
    handleCreate,
    handleWithdraw,
    handleRevise,
  };
}

export function UpliftRequestsSection({
  token,
  dispatchId,
  currentNte,
  upliftRequests,
  locked,
  onChanged,
  pollDocument,
}: UpliftRequestsSectionProps) {
  const evidence = useVendorUpliftEvidence({ pollDocument });
  const {
    submitting,
    formError,
    infoMessage,
    requestError,
    errorRequestId,
    handleCreate,
    handleWithdraw,
    handleRevise,
  } = useVendorUpliftActions({ token, dispatchId, currentNte, onChanged, evidence });

  const activeRequest = upliftRequests.find((request) => ACTIVE_STATUSES.has(request.status));
  const canShowForm = !locked && !activeRequest;

  return (
    <>
      {upliftRequests.length === 0 && !activeRequest && (
        <VendorPortalFeedback>
          No uplift requests yet. Use the form below if the work will exceed the current NTE.
        </VendorPortalFeedback>
      )}
      {Boolean(infoMessage) && <VendorPortalFeedback>{infoMessage}</VendorPortalFeedback>}

      {upliftRequests.map((request) => (
        <UpliftRequestCard
          key={request.id}
          request={request}
          locked={locked}
          canAct={!locked}
          uploadingPercent={evidence.uploadingPercent}
          submitting={submitting}
          errorMessage={errorRequestId === request.id ? requestError : ""}
          onWithdraw={(r) => void handleWithdraw(r)}
          onRevise={(r, values) => void handleRevise(r, values)}
          onCancelRevise={evidence.reset}
        />
      ))}

      {canShowForm && (
        <UpliftRequestForm
          mode="create"
          currentNte={currentNte}
          submitting={submitting}
          uploadingPercent={evidence.uploadingPercent}
          errorMessage={formError}
          onSubmit={(values) => void handleCreate(values)}
        />
      )}
    </>
  );
}