import { useState, useCallback } from "react";
import type {
  XOTemplate,
  XOInvitation,
  XOTemplateTransactionOutput,
} from "@xo-cash/types";
import type { VariableInput, SelectableUTXO } from "../types.js";
import {
  getTransactionOutputIdentifier,
  isInvitationRequirementsComplete,
  resolveProvidedLockingBytecodeHex,
} from "../../../../utils/invitation-flow.js";
import type { AppService } from "../../../../services/app.js";

interface InvitationManagerDeps {
  appService: AppService;
  showError: (msg: string) => void;
  showInfo: (msg: string) => void;
  setStatus: (msg: string) => void;
}

/**
 * Manages the full invitation lifecycle for transaction-based actions:
 * creation, variable persistence, output generation, input addition,
 * signing, and broadcasting.
 *
 * Only relevant for TransactionWizardFlow — data flows bypass this entirely.
 */
export function useInvitationManager(deps: InvitationManagerDeps) {
  const { appService, showError, showInfo, setStatus } = deps;

  const [invitation, setInvitation] = useState<XOInvitation | null>(null);
  const [invitationId, setInvitationId] = useState<string | null>(null);
  const [requirementsComplete, setRequirementsComplete] = useState(false);
  const [hasSignedAndBroadcasted, setHasSignedAndBroadcasted] = useState(false);
  const [isProcessing, setIsProcessing] = useState(false);

  /** Re-check whether all invitation requirements are satisfied. */
  const refreshRequirements = useCallback(
    async (identifier: string | null = invitationId): Promise<boolean> => {
      if (!identifier || !appService) {
        setRequirementsComplete(false);
        return false;
      }

      const instance = appService.invitations.find(
        (inv: any) => inv.data.invitationIdentifier === identifier,
      );
      if (!instance) {
        setRequirementsComplete(false);
        return false;
      }

      const complete = await isInvitationRequirementsComplete(instance);
      setRequirementsComplete(complete);
      return complete;
    },
    [appService, invitationId],
  );

  /**
   * Create an invitation, persist variable values, and add
   * template-required transaction outputs.
   *
   * @returns The invitation identifier on success, or null on failure.
   */
  const createWithVariables = useCallback(
    async (
      templateIdentifier: string,
      actionIdentifier: string,
      roleIdentifier: string,
      template: XOTemplate,
      variables: VariableInput[],
    ): Promise<string | null> => {
      if (!appService) return null;

      setIsProcessing(true);
      setStatus("Creating invitation...");

      try {
        // Create via the engine
        const xoInvitation = await appService.engine.createInvitation({
          templateIdentifier,
          actionIdentifier,
        });

        // Wrap and track
        const invitationInstance =
          await appService.createInvitation(xoInvitation);
        let inv = invitationInstance.data;
        const invId = inv.invitationIdentifier;
        setInvitationId(invId);

        // Persist variable values
        if (variables.length > 0) {
          setStatus("Adding variables...");
          const variableData = variables.map((v) => {
            const isNumeric =
              ["integer", "number", "satoshis"].includes(v.type) ||
              (v.hint && ["satoshis", "amount"].includes(v.hint));

            return {
              variableIdentifier: v.id,
              roleIdentifier,
              value: isNumeric ? BigInt(v.value || "0") : v.value,
            };
          });
          await invitationInstance.addVariables(variableData);
          inv = invitationInstance.data;
        }

        // Build variable values lookup for output resolution
        const variableValuesByIdentifier = variables.reduce(
          (acc, variable) => {
            if (
              typeof variable.value === "string" &&
              variable.value.trim().length > 0
            ) {
              acc[variable.id] = variable.value;
            }
            return acc;
          },
          {} as Record<string, string>,
        );

        // Add template-required transaction outputs
        const act = template.actions?.[actionIdentifier];
        const transaction = act?.transaction
          ? template.transactions?.[act.transaction]
          : null;

        if (transaction?.outputs && transaction.outputs.length > 0) {
          setStatus("Adding required outputs...");
          const outputsToAdd = await Promise.all(
            transaction.outputs.map(
              async (output: XOTemplateTransactionOutput) => {
                const outputIdentifier = getTransactionOutputIdentifier(output);
                if (!outputIdentifier) {
                  throw new Error("Invalid transaction output definition");
                }

                const providedHex = resolveProvidedLockingBytecodeHex(
                  template,
                  outputIdentifier,
                  variableValuesByIdentifier,
                );

                const lockingBytecodeHex =
                  providedHex ??
                  (await invitationInstance.generateLockingBytecode(
                    outputIdentifier,
                    roleIdentifier,
                  ));

                return {
                  outputIdentifier,
                  lockingBytecode: lockingBytecodeHex,
                };
              },
            ),
          );

          // TODO: Clean this up. Suggestions: 1. Convert to bytes above. 2. Have addOutputs accept a hex string. 3. Have addOutputs handle lockscript generation.
          await invitationInstance.addOutputs(
            outputsToAdd.map((output) => ({
              outputIdentifier: output.outputIdentifier,
              lockingBytecode: new Uint8Array(
                Buffer.from(output.lockingBytecode, "hex"),
              ),
            })),
          );

          inv = invitationInstance.data;
        }

        setInvitation(inv);
        await refreshRequirements(invId);
        setStatus("Invitation created");
        return invId;
      } catch (error) {
        showError(
          `Failed to create invitation: ${error instanceof Error ? error.message : String(error)}`,
        );
        return null;
      } finally {
        setIsProcessing(false);
      }
    },
    [appService, showError, setStatus, refreshRequirements],
  );

  /**
   * Add the selected UTXOs as inputs and a change output to the invitation.
   *
   * @returns true on success, false on failure.
   */
  const addInputsAndOutputs = useCallback(
    async (
      selectedUtxos: SelectableUTXO[],
      changeAmount: bigint,
    ): Promise<boolean> => {
      if (!invitationId || !appService) return false;

      setIsProcessing(true);
      setStatus("Adding inputs and outputs...");

      try {
        const instance = appService.invitations.find(
          (inv: any) => inv.data.invitationIdentifier === invitationId,
        );
        if (!instance) throw new Error("Invitation not found");

        const inputs = selectedUtxos.map((utxo) => ({
          outpointTransactionHash: new Uint8Array(
            Buffer.from(utxo.outpointTransactionHash, "hex"),
          ),
          outpointIndex: utxo.outpointIndex,
        }));

        await instance.addInputs(inputs);
        await instance.addOutputs([{ valueSatoshis: changeAmount }]);
        await refreshRequirements(invitationId);
        setStatus("Inputs and outputs added");
        return true;
      } catch (error) {
        showError(
          `Failed to add inputs/outputs: ${error instanceof Error ? error.message : String(error)}`,
        );
        return false;
      } finally {
        setIsProcessing(false);
      }
    },
    [invitationId, appService, showError, setStatus, refreshRequirements],
  );

  /** Sign the invitation and broadcast the transaction. */
  const signAndBroadcast = useCallback(async (): Promise<boolean> => {
    if (!invitationId || !appService) return false;

    setIsProcessing(true);
    setStatus("Signing invitation...");

    try {
      const instance = appService.invitations.find(
        (inv: any) => inv.data.invitationIdentifier === invitationId,
      );
      if (!instance) throw new Error("Invitation not found");

      const complete = await refreshRequirements(invitationId);
      if (!complete) {
        showError("Invitation requirements are not complete yet.");
        return false;
      }

      await instance.sign();
      setStatus("Broadcasting transaction...");
      await instance.broadcast();
      setHasSignedAndBroadcasted(true);
      setStatus("Transaction signed and broadcasted");
      showInfo("Transaction signed and broadcasted.");
      await refreshRequirements(invitationId);
      return true;
    } catch (error) {
      showError(
        `Failed to sign and broadcast: ${error instanceof Error ? error.message : String(error)}`,
      );
      return false;
    } finally {
      setIsProcessing(false);
    }
  }, [
    invitationId,
    appService,
    setStatus,
    showError,
    showInfo,
    refreshRequirements,
  ]);

  return {
    invitation,
    invitationId,
    requirementsComplete,
    hasSignedAndBroadcasted,
    isProcessing,
    setIsProcessing,
    refreshRequirements,
    createWithVariables,
    addInputsAndOutputs,
    signAndBroadcast,
  } as const;
}

export type InvitationManagerState = ReturnType<typeof useInvitationManager>;