'use client';

import { useCallback, useEffect, useId, useMemo, useRef, useState } from 'react';

import type { DropResult, SensorAPI } from '@hello-pangea/dnd';
import { DragDropContext, Draggable, Droppable } from '@hello-pangea/dnd';
import { zodResolver } from '@hookform/resolvers/zod';
import { Trans, msg } from '@lingui/macro';
import { useLingui } from '@lingui/react';
import { motion } from 'framer-motion';
import { GripVerticalIcon, Link2Icon, Plus, Trash } from 'lucide-react';
import { useSession } from 'next-auth/react';
import { useFieldArray, useForm } from 'react-hook-form';

import { ZRecipientAuthOptionsSchema } from '@documenso/lib/types/document-auth';
import { nanoid } from '@documenso/lib/universal/id';
import { generateRecipientPlaceholder } from '@documenso/lib/utils/templates';
import type { TemplateDirectLink } from '@documenso/prisma/client';
import {
  DocumentSigningOrder,
  type Field,
  type Recipient,
  RecipientRole,
} from '@documenso/prisma/client';
import { AnimateGenericFadeInOut } from '@documenso/ui/components/animate/animate-generic-fade-in-out';
import { RecipientActionAuthSelect } from '@documenso/ui/components/recipient/recipient-action-auth-select';
import { RecipientRoleSelect } from '@documenso/ui/components/recipient/recipient-role-select';
import { cn } from '@documenso/ui/lib/utils';
import { Button } from '@documenso/ui/primitives/button';
import { FormErrorMessage } from '@documenso/ui/primitives/form/form-error-message';
import { Input } from '@documenso/ui/primitives/input';

import { Checkbox } from '../checkbox';
import {
  DocumentFlowFormContainerActions,
  DocumentFlowFormContainerContent,
  DocumentFlowFormContainerFooter,
  DocumentFlowFormContainerHeader,
  DocumentFlowFormContainerStep,
} from '../document-flow/document-flow-root';
import { ShowFieldItem } from '../document-flow/show-field-item';
import type { DocumentFlowStep } from '../document-flow/types';
import { Form, FormControl, FormField, FormItem, FormLabel, FormMessage } from '../form/form';
import { useStep } from '../stepper';
import { Tooltip, TooltipContent, TooltipTrigger } from '../tooltip';
import type { TAddTemplatePlacholderRecipientsFormSchema } from './add-template-placeholder-recipients.types';
import { ZAddTemplatePlacholderRecipientsFormSchema } from './add-template-placeholder-recipients.types';

export type AddTemplatePlaceholderRecipientsFormProps = {
  documentFlow: DocumentFlowStep;
  recipients: Recipient[];
  fields: Field[];
  signingOrder?: DocumentSigningOrder | null;
  templateDirectLink: TemplateDirectLink | null;
  isEnterprise: boolean;
  isDocumentPdfLoaded: boolean;
  onSubmit: (_data: TAddTemplatePlacholderRecipientsFormSchema) => void;
};

export const AddTemplatePlaceholderRecipientsFormPartial = ({
  documentFlow,
  isEnterprise,
  recipients,
  templateDirectLink,
  fields,
  signingOrder,
  isDocumentPdfLoaded,
  onSubmit,
}: AddTemplatePlaceholderRecipientsFormProps) => {
  const initialId = useId();
  const $sensorApi = useRef<SensorAPI | null>(null);

  const { _ } = useLingui();
  const { data: session } = useSession();

  const user = session?.user;

  const [placeholderRecipientCount, setPlaceholderRecipientCount] = useState(() =>
    recipients.length > 1 ? recipients.length + 1 : 2,
  );

  const { currentStep, totalSteps, previousStep } = useStep();

  const generateDefaultFormSigners = () => {
    if (recipients.length === 0) {
      return [
        {
          formId: initialId,
          role: RecipientRole.SIGNER,
          actionAuth: undefined,
          ...generateRecipientPlaceholder(1),
          signingOrder: 1,
        },
      ];
    }

    let mappedRecipients = recipients.map((recipient, index) => ({
      nativeId: recipient.id,
      formId: String(recipient.id),
      name: recipient.name,
      email: recipient.email,
      role: recipient.role,
      actionAuth: ZRecipientAuthOptionsSchema.parse(recipient.authOptions)?.actionAuth ?? undefined,
      signingOrder: recipient.signingOrder ?? index + 1,
    }));

    if (signingOrder === DocumentSigningOrder.SEQUENTIAL) {
      mappedRecipients = mappedRecipients.sort(
        (a, b) => (a.signingOrder ?? 0) - (b.signingOrder ?? 0),
      );
    }

    return mappedRecipients;
  };

  const form = useForm<TAddTemplatePlacholderRecipientsFormSchema>({
    resolver: zodResolver(ZAddTemplatePlacholderRecipientsFormSchema),
    defaultValues: {
      signers: generateDefaultFormSigners(),
      signingOrder: signingOrder || DocumentSigningOrder.PARALLEL,
    },
  });

  useEffect(() => {
    form.reset({
      signers: generateDefaultFormSigners(),
      signingOrder: signingOrder || DocumentSigningOrder.PARALLEL,
    });

    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [recipients]);

  // Always show advanced settings if any recipient has auth options.
  const alwaysShowAdvancedSettings = useMemo(() => {
    const recipientHasAuthOptions = recipients.find((recipient) => {
      const recipientAuthOptions = ZRecipientAuthOptionsSchema.parse(recipient.authOptions);

      return recipientAuthOptions?.accessAuth || recipientAuthOptions?.actionAuth;
    });

    const formHasActionAuth = form.getValues('signers').find((signer) => signer.actionAuth);

    return recipientHasAuthOptions !== undefined || formHasActionAuth !== undefined;
  }, [recipients, form]);

  const [showAdvancedSettings, setShowAdvancedSettings] = useState(alwaysShowAdvancedSettings);

  const {
    formState: { errors, isSubmitting },
    control,
    watch,
  } = form;

  const watchedSigners = watch('signers');
  const isSigningOrderSequential = watch('signingOrder') === DocumentSigningOrder.SEQUENTIAL;

  const normalizeSigningOrders = (signers: typeof watchedSigners) => {
    return signers
      .sort((a, b) => (a.signingOrder ?? 0) - (b.signingOrder ?? 0))
      .map((signer, index) => ({ ...signer, signingOrder: index + 1 }));
  };

  const onFormSubmit = form.handleSubmit(onSubmit);

  const {
    append: appendSigner,
    fields: signers,
    remove: removeSigner,
  } = useFieldArray({
    control,
    name: 'signers',
  });

  const onAddPlaceholderSelfRecipient = () => {
    appendSigner({
      formId: nanoid(12),
      name: user?.name ?? '',
      email: user?.email ?? '',
      role: RecipientRole.SIGNER,
      signingOrder: signers.length > 0 ? (signers[signers.length - 1]?.signingOrder ?? 0) + 1 : 1,
    });
  };

  const onAddPlaceholderRecipient = () => {
    appendSigner({
      formId: nanoid(12),
      role: RecipientRole.SIGNER,
      ...generateRecipientPlaceholder(placeholderRecipientCount),
      signingOrder: signers.length > 0 ? (signers[signers.length - 1]?.signingOrder ?? 0) + 1 : 1,
    });

    setPlaceholderRecipientCount((count) => count + 1);
  };

  const onRemoveSigner = (index: number) => {
    removeSigner(index);
    const updatedSigners = signers.filter((_, idx) => idx !== index);
    form.setValue('signers', normalizeSigningOrders(updatedSigners));
  };

  const isSignerDirectRecipient = (
    signer: TAddTemplatePlacholderRecipientsFormSchema['signers'][number],
  ): boolean => {
    return (
      templateDirectLink !== null &&
      signer.nativeId === templateDirectLink?.directTemplateRecipientId
    );
  };

  const onDragEnd = useCallback(
    async (result: DropResult) => {
      if (!result.destination) return;

      const items = Array.from(watchedSigners);
      const [reorderedSigner] = items.splice(result.source.index, 1);

      const insertIndex = result.destination.index;

      items.splice(insertIndex, 0, reorderedSigner);

      const updatedSigners = items.map((item, index) => ({
        ...item,
        signingOrder: index + 1,
      }));

      updatedSigners.forEach((item, index) => {
        const keys: (keyof typeof item)[] = [
          'formId',
          'nativeId',
          'email',
          'name',
          'role',
          'signingOrder',
          'actionAuth',
        ];
        keys.forEach((key) => {
          form.setValue(`signers.${index}.${key}` as const, item[key]);
        });
      });

      const currentLength = form.getValues('signers').length;
      if (currentLength > updatedSigners.length) {
        for (let i = updatedSigners.length; i < currentLength; i++) {
          form.unregister(`signers.${i}`);
        }
      }

      await form.trigger('signers');
    },
    [form, watchedSigners],
  );

  const triggerDragAndDrop = useCallback(
    (fromIndex: number, toIndex: number) => {
      if (!$sensorApi.current) {
        return;
      }

      const draggableId = signers[fromIndex].id;

      const preDrag = $sensorApi.current.tryGetLock(draggableId);

      if (!preDrag) {
        return;
      }

      const drag = preDrag.snapLift();

      setTimeout(() => {
        // Move directly to the target index
        if (fromIndex < toIndex) {
          for (let i = fromIndex; i < toIndex; i++) {
            drag.moveDown();
          }
        } else {
          for (let i = fromIndex; i > toIndex; i--) {
            drag.moveUp();
          }
        }

        setTimeout(() => {
          drag.drop();
        }, 500);
      }, 0);
    },
    [signers],
  );

  const updateSigningOrders = useCallback(
    (newIndex: number, oldIndex: number) => {
      const updatedSigners = form.getValues('signers').map((signer, index) => {
        if (index === oldIndex) {
          return { ...signer, signingOrder: newIndex + 1 };
        } else if (index >= newIndex && index < oldIndex) {
          return { ...signer, signingOrder: (signer.signingOrder ?? index + 1) + 1 };
        } else if (index <= newIndex && index > oldIndex) {
          return { ...signer, signingOrder: Math.max(1, (signer.signingOrder ?? index + 1) - 1) };
        }
        return signer;
      });

      updatedSigners.forEach((signer, index) => {
        form.setValue(`signers.${index}.signingOrder`, signer.signingOrder);
      });
    },
    [form],
  );

  const handleSigningOrderChange = useCallback(
    (index: number, newOrderString: string) => {
      const newOrder = parseInt(newOrderString, 10);

      if (!newOrderString.trim()) {
        return;
      }

      if (Number.isNaN(newOrder)) {
        form.setValue(`signers.${index}.signingOrder`, index + 1);
        return;
      }

      const newIndex = newOrder - 1;
      if (index !== newIndex) {
        updateSigningOrders(newIndex, index);
        triggerDragAndDrop(index, newIndex);
      }
    },
    [form, triggerDragAndDrop, updateSigningOrders],
  );

  return (
    <>
      <DocumentFlowFormContainerHeader
        title={documentFlow.title}
        description={documentFlow.description}
      />
      <DocumentFlowFormContainerContent>
        {isDocumentPdfLoaded &&
          fields.map((field, index) => (
            <ShowFieldItem key={index} field={field} recipients={recipients} />
          ))}

        <AnimateGenericFadeInOut motionKey={showAdvancedSettings ? 'Show' : 'Hide'}>
          <Form {...form}>
            {/* Enable sequential signing checkbox */}
            <FormField
              control={form.control}
              name="signingOrder"
              render={({ field }) => (
                <FormItem className="mb-6 flex flex-row items-center space-x-2 space-y-0">
                  <FormControl>
                    <Checkbox
                      {...field}
                      id="signingOrder"
                      checkClassName="text-white"
                      checked={field.value === DocumentSigningOrder.SEQUENTIAL}
                      onCheckedChange={(checked) =>
                        field.onChange(
                          checked ? DocumentSigningOrder.SEQUENTIAL : DocumentSigningOrder.PARALLEL,
                        )
                      }
                      disabled={isSubmitting}
                    />
                  </FormControl>

                  <FormLabel
                    htmlFor="signingOrder"
                    className="text-sm leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70"
                  >
                    <Trans>Enable signing order</Trans>
                  </FormLabel>
                </FormItem>
              )}
            />

            {/* Drag and drop context */}
            <DragDropContext
              onDragEnd={onDragEnd}
              sensors={[
                (api: SensorAPI) => {
                  $sensorApi.current = api;
                },
              ]}
            >
              <Droppable droppableId="signers">
                {(provided) => (
                  <div
                    {...provided.droppableProps}
                    ref={provided.innerRef}
                    className="flex w-full flex-col gap-y-2"
                  >
                    {signers.map((signer, index) => (
                      <Draggable
                        key={`${signer.id}-${signer.signingOrder}`}
                        draggableId={signer.id}
                        index={index}
                        isDragDisabled={
                          !isSigningOrderSequential ||
                          isSubmitting ||
                          isSignerDirectRecipient(signer) ||
                          !signer.signingOrder
                        }
                      >
                        {(provided, snapshot) => (
                          <div
                            ref={provided.innerRef}
                            {...provided.draggableProps}
                            {...provided.dragHandleProps}
                            className={cn('py-1', {
                              'bg-widget-foreground pointer-events-none rounded-md pt-2':
                                snapshot.isDragging,
                            })}
                          >
                            <motion.fieldset
                              data-native-id={signer.nativeId}
                              disabled={isSubmitting || isSignerDirectRecipient(signer)}
                              className={cn('grid grid-cols-10 items-end gap-2 pb-2', {
                                'border-b pt-2': showAdvancedSettings,
                                'grid-cols-12 pr-3': isSigningOrderSequential,
                              })}
                            >
                              {isSigningOrderSequential && (
                                <FormField
                                  control={form.control}
                                  name={`signers.${index}.signingOrder`}
                                  render={({ field }) => (
                                    <FormItem className="col-span-2 mt-auto flex items-center gap-x-1 space-y-0">
                                      <GripVerticalIcon className="h-5 w-5 flex-shrink-0 opacity-40" />
                                      <FormControl>
                                        <Input
                                          type="number"
                                          max={signers.length}
                                          className={cn(
                                            'w-full text-center',
                                            '[appearance:textfield] [&::-webkit-inner-spin-button]:appearance-none [&::-webkit-outer-spin-button]:appearance-none',
                                          )}
                                          {...field}
                                          onChange={(e) => {
                                            field.onChange(e);
                                            handleSigningOrderChange(index, e.target.value);
                                          }}
                                          onBlur={(e) => {
                                            field.onBlur();
                                            handleSigningOrderChange(index, e.target.value);
                                          }}
                                          disabled={
                                            snapshot.isDragging ||
                                            isSubmitting ||
                                            isSignerDirectRecipient(signer)
                                          }
                                        />
                                      </FormControl>
                                      <FormMessage />
                                    </FormItem>
                                  )}
                                />
                              )}

                              <FormField
                                control={form.control}
                                name={`signers.${index}.email`}
                                render={({ field }) => (
                                  <FormItem
                                    className={cn('relative', {
                                      'col-span-4': !showAdvancedSettings,
                                      'col-span-5': showAdvancedSettings,
                                    })}
                                  >
                                    {!showAdvancedSettings && index === 0 && (
                                      <FormLabel required>
                                        <Trans>Email</Trans>
                                      </FormLabel>
                                    )}

                                    <FormControl>
                                      <Input
                                        type="email"
                                        placeholder={_(msg`Email`)}
                                        {...field}
                                        disabled={
                                          field.disabled ||
                                          isSubmitting ||
                                          signers[index].email === user?.email ||
                                          isSignerDirectRecipient(signer)
                                        }
                                      />
                                    </FormControl>

                                    <FormMessage />
                                  </FormItem>
                                )}
                              />

                              <FormField
                                control={form.control}
                                name={`signers.${index}.name`}
                                render={({ field }) => (
                                  <FormItem
                                    className={cn({
                                      'col-span-4': !showAdvancedSettings,
                                      'col-span-5': showAdvancedSettings,
                                    })}
                                  >
                                    {!showAdvancedSettings && index === 0 && (
                                      <FormLabel>
                                        <Trans>Name</Trans>
                                      </FormLabel>
                                    )}

                                    <FormControl>
                                      <Input
                                        placeholder={_(msg`Name`)}
                                        {...field}
                                        disabled={
                                          field.disabled ||
                                          isSubmitting ||
                                          signers[index].email === user?.email ||
                                          isSignerDirectRecipient(signer)
                                        }
                                      />
                                    </FormControl>

                                    <FormMessage />
                                  </FormItem>
                                )}
                              />

                              {showAdvancedSettings && isEnterprise && (
                                <FormField
                                  control={form.control}
                                  name={`signers.${index}.actionAuth`}
                                  render={({ field }) => (
                                    <FormItem
                                      className={cn('col-span-8', {
                                        'col-span-10': isSigningOrderSequential,
                                      })}
                                    >
                                      <FormControl>
                                        <RecipientActionAuthSelect
                                          {...field}
                                          onValueChange={field.onChange}
                                          disabled={isSubmitting}
                                        />
                                      </FormControl>

                                      <FormMessage />
                                    </FormItem>
                                  )}
                                />
                              )}

                              <div className="col-span-2 flex gap-x-2">
                                <FormField
                                  name={`signers.${index}.role`}
                                  render={({ field }) => (
                                    <FormItem className="col-span-1 mt-auto">
                                      <FormControl>
                                        <RecipientRoleSelect
                                          {...field}
                                          onValueChange={field.onChange}
                                          disabled={isSubmitting}
                                          hideCCRecipients={isSignerDirectRecipient(signer)}
                                        />
                                      </FormControl>

                                      <FormMessage />
                                    </FormItem>
                                  )}
                                />

                                {isSignerDirectRecipient(signer) ? (
                                  <Tooltip>
                                    <TooltipTrigger className="col-span-1 mt-auto inline-flex h-10 w-10 items-center justify-center text-slate-500 hover:opacity-80">
                                      <Link2Icon className="h-4 w-4" />
                                    </TooltipTrigger>
                                    <TooltipContent className="text-foreground z-9999 max-w-md p-4">
                                      <h3 className="text-foreground text-lg font-semibold">
                                        <Trans>Direct link receiver</Trans>
                                      </h3>
                                      <p className="text-muted-foreground mt-1">
                                        <Trans>
                                          This field cannot be modified or deleted. When you share
                                          this template's direct link or add it to your public
                                          profile, anyone who accesses it can input their name and
                                          email, and fill in the fields assigned to them.
                                        </Trans>
                                      </p>
                                    </TooltipContent>
                                  </Tooltip>
                                ) : (
                                  <button
                                    type="button"
                                    className="col-span-1 mt-auto inline-flex h-10 w-10 items-center justify-center text-slate-500 hover:opacity-80 disabled:cursor-not-allowed disabled:opacity-50"
                                    disabled={isSubmitting || signers.length === 1}
                                    onClick={() => onRemoveSigner(index)}
                                  >
                                    <Trash className="h-5 w-5" />
                                  </button>
                                )}
                              </div>
                            </motion.fieldset>
                          </div>
                        )}
                      </Draggable>
                    ))}

                    {provided.placeholder}
                  </div>
                )}
              </Droppable>
            </DragDropContext>

            <FormErrorMessage
              className="mt-2"
              // Dirty hack to handle errors when .root is populated for an array type
              error={'signers__root' in errors && errors['signers__root']}
            />

            <div
              className={cn('mt-2 flex flex-row items-center space-x-4', {
                'mt-4': showAdvancedSettings,
              })}
            >
              <Button
                type="button"
                className="flex-1"
                disabled={isSubmitting}
                onClick={() => onAddPlaceholderRecipient()}
              >
                <Plus className="-ml-1 mr-2 h-5 w-5" />
                <Trans>Add Placeholder Recipient</Trans>
              </Button>

              <Button
                type="button"
                className="dark:bg-muted dark:hover:bg-muted/80 bg-black/5 hover:bg-black/10"
                variant="secondary"
                disabled={
                  isSubmitting ||
                  form.getValues('signers').some((signer) => signer.email === user?.email)
                }
                onClick={() => onAddPlaceholderSelfRecipient()}
              >
                <Plus className="-ml-1 mr-2 h-5 w-5" />
                <Trans>Add Myself</Trans>
              </Button>
            </div>

            {!alwaysShowAdvancedSettings && isEnterprise && (
              <div className="mt-4 flex flex-row items-center">
                <Checkbox
                  id="showAdvancedRecipientSettings"
                  className="h-5 w-5"
                  checkClassName="dark:text-white text-primary"
                  checked={showAdvancedSettings}
                  onCheckedChange={(value) => setShowAdvancedSettings(Boolean(value))}
                />

                <label
                  className="text-muted-foreground ml-2 text-sm"
                  htmlFor="showAdvancedRecipientSettings"
                >
                  <Trans>Show advanced settings</Trans>
                </label>
              </div>
            )}
          </Form>
        </AnimateGenericFadeInOut>
      </DocumentFlowFormContainerContent>

      <DocumentFlowFormContainerFooter>
        <DocumentFlowFormContainerStep step={currentStep} maxStep={totalSteps} />

        <DocumentFlowFormContainerActions
          loading={isSubmitting}
          disabled={isSubmitting}
          canGoBack={currentStep > 1}
          onGoBackClick={() => previousStep()}
          onGoNextClick={() => void onFormSubmit()}
        />
      </DocumentFlowFormContainerFooter>
    </>
  );
};