"use client";

import {
  useCallback,
  useEffect,
  useMemo,
  useState,
  type ClipboardEvent,
} from "react";
import { useSearchParams } from "next/navigation";
import Button from "../../../../components/buttons/Button";
import InlineTextButton from "../../../../components/buttons/InlineTextButton";
import TextInput from "../../../../components/controls/TextInput";
import Icon from "../../../../components/asset/icon";
import { ASSETS, getAssetPath } from "../../../../../lib/assetUtils";
import { useTranslation } from "../../../../contexts/MessagesContext";
import { fetchAuthSession } from "../../../../../lib/create/api";
import { membershipInvitePreview } from "../../../../../lib/create/membershipInvitePreview";
import {
  INVITE_EMAIL_PATTERN,
  formatInviteCountWord,
  parseInvitePaste,
} from "../../../../../lib/create/parseInviteEmails";
import { MAX_STAKEHOLDER_EMAILS } from "../../../../../lib/create/stakeholderLimits";
import { useCreateFlow } from "../../context/CreateFlowContext";
import { MembershipInvitePreviewCard } from "../../components/MembershipInvitePreviewCard";
import { CreateFlowHeaderLockup } from "../../components/CreateFlowHeaderLockup";
import { CreateFlowTwoColumnSelectShell } from "../../components/CreateFlowTwoColumnSelectShell";
import {
  CREATE_FLOW_MANAGE_STAKEHOLDERS_QUERY,
  CREATE_FLOW_MANAGE_STAKEHOLDERS_VALUE,
} from "../../utils/flowSteps";
import { PublishedStakeholdersManagePanel } from "./PublishedStakeholdersManagePanel";

const VISIBLE_WHEN_COLLAPSED = 6;

function InvitePersonRow({
  email,
  youLabel,
  removeAria,
  onRemove,
}: {
  email: string;
  youLabel?: string;
  removeAria: string;
  onRemove?: () => void;
}) {
  return (
    <div className="flex w-full items-center gap-[var(--space-300)] border-b border-[var(--color-border-default-secondary)] py-[var(--space-200)]">
      <div className="flex min-w-0 flex-1 items-center gap-[var(--space-200)]">
        <p className="truncate text-medium-paragraph text-[var(--color-content-default-primary)]">
          {email}
        </p>
        {youLabel ? (
          <p className="shrink-0 text-small-label text-[var(--color-content-default-tertiary)]">
            {youLabel}
          </p>
        ) : null}
      </div>
      {onRemove ? (
        <button
          type="button"
          onClick={onRemove}
          aria-label={removeAria}
          className="flex size-[30px] shrink-0 items-center justify-center rounded-full bg-[var(--color-surface-default-secondary)] focus:outline-none focus-visible:ring-2 focus-visible:ring-[var(--color-border-invert-primary)]"
        >
          {/* eslint-disable-next-line @next/next/no-img-element -- icon asset */}
          <img
            src={getAssetPath(ASSETS.ICON_CLOSE)}
            alt=""
            width={14}
            height={14}
            className="size-[14px]"
          />
        </button>
      ) : null}
    </div>
  );
}

export function ConfirmStakeholdersScreen() {
  const searchParams = useSearchParams();
  const { state, updateState, markCreateFlowInteraction } = useCreateFlow();
  const t = useTranslation("create.reviewAndComplete.confirmStakeholders");

  const manageStakeholdersIntent =
    searchParams?.get(CREATE_FLOW_MANAGE_STAKEHOLDERS_QUERY) ===
    CREATE_FLOW_MANAGE_STAKEHOLDERS_VALUE;
  const editingPublishedRuleId = state.editingPublishedRuleId?.trim() ?? "";

  const [ownerEmail, setOwnerEmail] = useState<string | null>(null);
  const [draftEmail, setDraftEmail] = useState("");
  const [fieldError, setFieldError] = useState<string | null>(null);
  const [pasteResult, setPasteResult] = useState<string | null>(null);
  const [expanded, setExpanded] = useState(false);

  useEffect(() => {
    let cancelled = false;
    void fetchAuthSession().then(({ user }) => {
      if (cancelled) return;
      const email = user?.email?.trim().toLowerCase() ?? "";
      setOwnerEmail(email.length > 0 ? email : null);
    });
    return () => {
      cancelled = true;
    };
  }, []);

  const invitees = useMemo(() => {
    const raw = state.stakeholderEmails ?? [];
    const owner = ownerEmail;
    return raw
      .map((email) => email.trim().toLowerCase())
      .filter((email) => email.length > 0 && email !== owner);
  }, [state.stakeholderEmails, ownerEmail]);

  const rows = useMemo(() => {
    const list: Array<{ email: string; isYou: boolean }> = [];
    if (ownerEmail) {
      list.push({ email: ownerEmail, isYou: true });
    }
    for (const email of invitees) {
      list.push({ email, isYou: false });
    }
    return list;
  }, [ownerEmail, invitees]);

  const visibleRows = expanded
    ? rows
    : rows.slice(0, VISIBLE_WHEN_COLLAPSED);
  const hiddenCount = Math.max(0, rows.length - visibleRows.length);

  const preview = membershipInvitePreview(state);

  const countLine =
    rows.length === 1
      ? t("countOne")
      : t("countMany").replace("{count}", String(rows.length));

  const persistInvitees = useCallback(
    (next: string[]) => {
      updateState({ stakeholderEmails: next });
    },
    [updateState],
  );

  const addOne = useCallback(
    (raw: string): boolean => {
      const trimmed = raw.trim().toLowerCase();
      if (!INVITE_EMAIL_PATTERN.test(trimmed)) {
        setFieldError(t("invalidEmail"));
        return false;
      }
      if (ownerEmail && trimmed === ownerEmail) {
        setFieldError(t("duplicateEmail"));
        return false;
      }
      if (invitees.includes(trimmed)) {
        setFieldError(t("duplicateEmail"));
        return false;
      }
      if (invitees.length >= MAX_STAKEHOLDER_EMAILS) {
        setFieldError(t("maxStakeholders"));
        return false;
      }
      persistInvitees([...invitees, trimmed]);
      return true;
    },
    [invitees, ownerEmail, persistInvitees, t],
  );

  const handleAdd = () => {
    markCreateFlowInteraction();
    setPasteResult(null);
    if (addOne(draftEmail)) {
      setDraftEmail("");
      setFieldError(null);
    }
  };

  const handlePaste = (event: ClipboardEvent<HTMLDivElement>) => {
    const text = event.clipboardData.getData("text");
    const tokens = text
      .split(/[\s,;]+/)
      .map((token) => token.trim())
      .filter((token) => token.length > 0);
    if (tokens.length <= 1) return;

    event.preventDefault();
    markCreateFlowInteraction();
    setFieldError(null);

    const existing = ownerEmail ? [ownerEmail, ...invitees] : [...invitees];
    const parsed = parseInvitePaste(text, existing, MAX_STAKEHOLDER_EMAILS);
    if (parsed.added.length > 0) {
      persistInvitees([...invitees, ...parsed.added]);
    }
    setDraftEmail(parsed.invalidRemainder);
    if (parsed.invalidRemainder.length > 0) {
      setFieldError(t("invalidEmail"));
    }

    const parts: string[] = [];
    if (parsed.added.length > 0) {
      const people =
        parsed.added.length === 1 ? t("peopleNounOne") : t("peopleNounMany");
      parts.push(
        t("pasteAdded")
          .replace("{count}", formatInviteCountWord(parsed.added.length))
          .replace("{people}", people),
      );
    }
    const invalidCount = parsed.invalidRemainder
      .split(",")
      .map((item) => item.trim())
      .filter((item) => item.length > 0).length;
    if (invalidCount === 1) {
      parts.push(t("pasteInvalidOne"));
    } else if (invalidCount > 1) {
      parts.push(
        t("pasteInvalidMany").replace(
          "{count}",
          formatInviteCountWord(invalidCount),
        ),
      );
    }
    setPasteResult(parts.length > 0 ? parts.join(" ") : null);
  };

  const handleRemove = (email: string) => {
    markCreateFlowInteraction();
    setPasteResult(null);
    persistInvitees(invitees.filter((item) => item !== email));
  };

  const header = (
    <div className="flex w-full min-w-0 flex-col gap-[var(--space-800)]">
      <CreateFlowHeaderLockup
        title={t("title")}
        description={t("description")}
        justification="left"
      />
      {preview ? (
        <MembershipInvitePreviewCard
          preview={preview}
          fromYourRuleLabel={t("fromYourRule")}
          whoBelongsLabel={t("whoBelongsLabel")}
          joiningLabel={t("joiningLabel")}
        />
      ) : null}
    </div>
  );

  if (manageStakeholdersIntent) {
    return (
      <CreateFlowTwoColumnSelectShell header={header} lgVerticalAlign="start">
        {editingPublishedRuleId.length > 0 ? (
          <PublishedStakeholdersManagePanel ruleId={editingPublishedRuleId} />
        ) : null}
      </CreateFlowTwoColumnSelectShell>
    );
  }

  return (
    <CreateFlowTwoColumnSelectShell header={header} lgVerticalAlign="start">
      <div className="flex w-full min-w-0 flex-col gap-[var(--space-600)]">
        <div
          className="flex w-full items-start gap-[var(--space-200)]"
          onPasteCapture={handlePaste}
        >
          <div className="min-w-0 flex-1">
            <TextInput
              id="invite-member-email"
              type="email"
              inputSize="small"
              showHelpIcon={false}
              label={t("emailLabel")}
              placeholder={t("emailPlaceholder")}
              value={draftEmail}
              autoComplete="email"
              autoFocus
              error={Boolean(fieldError)}
              textHint={fieldError || false}
              onChange={(event) => {
                setDraftEmail(event.target.value);
                setFieldError(null);
                setPasteResult(null);
              }}
              onKeyDown={(event) => {
                if (event.key !== "Enter") return;
                event.preventDefault();
                handleAdd();
              }}
            />
          </div>
          <div className="shrink-0 pt-[29px]">
            <Button
              type="button"
              size="small"
              buttonType="outline"
              palette="default"
              onClick={handleAdd}
            >
              {t("add")}
            </Button>
          </div>
        </div>

        {pasteResult ? (
          <div className="flex items-center gap-2" role="status">
            <Icon name="warning" size={24} />
            <p className="text-medium-label text-[var(--color-content-default-primary)]">
              {pasteResult}
            </p>
          </div>
        ) : null}

        {rows.length > 0 ? (
          <div className="flex w-full flex-col border-t border-[var(--color-border-default-secondary)]">
            {visibleRows.map((row) => (
              <InvitePersonRow
                key={row.isYou ? `you:${row.email}` : row.email}
                email={row.email}
                youLabel={row.isYou ? t("you") : undefined}
                removeAria={t("removeAria").replace("{email}", row.email)}
                onRemove={
                  row.isYou ? undefined : () => handleRemove(row.email)
                }
              />
            ))}
            {hiddenCount > 0 ? (
              <div className="pt-[var(--space-300)] pb-[var(--space-100)]">
                <InlineTextButton
                  onClick={() => {
                    markCreateFlowInteraction();
                    setExpanded(true);
                  }}
                >
                  {t("showMore").replace("{count}", String(hiddenCount))}
                </InlineTextButton>
              </div>
            ) : null}
          </div>
        ) : null}

        {rows.length > 0 ? (
          <p className="text-medium-label text-[var(--color-content-default-primary)]">
            {countLine}
          </p>
        ) : null}
        <p className="text-small-paragraph text-[var(--color-content-default-secondary)]">
          {t("privacy")}
        </p>
      </div>
    </CreateFlowTwoColumnSelectShell>
  );
}