import { useEffect, useMemo, useRef, useState } from "react";
import { Search, Pencil, Plus, Trash2 } from "lucide-react";
import type { ApiSettings } from "@govoplan/core-webui";
import { Button } from "@govoplan/core-webui";
import { ConfirmDialog } from "@govoplan/core-webui";
import { DataGrid, type DataGridColumn } from "@govoplan/core-webui";
import { Dialog } from "@govoplan/core-webui";
import { FormField } from "@govoplan/core-webui";
import { PasswordField } from "@govoplan/core-webui";
import { StatusBadge } from "@govoplan/core-webui";
import {
  createSystemAccount,
  fetchSystemAccountsDelta,
  fetchTenants,
  updateSystemAccount,
  updateSystemAccountRoles,
  updateSystemMemberships,
  type RoleSummary,
  type SystemAccountItem,
  type SystemMembershipDraft,
  type TenantAdminItem
} from "../../api/admin";
import { AdminIconButton, AdminPageLayout, AdminSelectionList, adminErrorMessage, formatAdminDateTime as formatDateTime, joinLabels, i18nMessage, mergeDeltaRows, useDeltaWatermarks, useUnsavedDraftGuard } from "@govoplan/core-webui";

const emptyDraft = {
  email: "",
  displayName: "",
  password: "",
  passwordResetRequired: true,
  isActive: true,
  roleIds: [] as string[],
  memberships: [] as SystemMembershipDraft[]
};

export default function SystemUsersPanel({
  settings,
  canCreate,
  canUpdate,
  canSuspend,
  canAssignRoles,
  canManageMemberships,
  onAuthRefresh








}: {settings: ApiSettings;canCreate: boolean;canUpdate: boolean;canSuspend: boolean;canAssignRoles: boolean;canManageMemberships: boolean;onAuthRefresh: () => Promise<void>;}) {
  const [accounts, setAccounts] = useState<SystemAccountItem[]>([]);
  const [roles, setRoles] = useState<RoleSummary[]>([]);
  const [tenants, setTenants] = useState<TenantAdminItem[]>([]);
  const accountsRef = useRef<SystemAccountItem[]>([]);
  const rolesRef = useRef<RoleSummary[]>([]);
  const { getDeltaWatermark, setDeltaWatermark, resetDeltaWatermark } = useDeltaWatermarks();
  const [editing, setEditing] = useState<SystemAccountItem | "new" | null>(null);
  const [viewing, setViewing] = useState<SystemAccountItem | null>(null);
  const [deactivating, setDeactivating] = useState<SystemAccountItem | null>(null);
  const [temporaryPassword, setTemporaryPassword] = useState<{email: string;value: string;} | null>(null);
  const [draft, setDraft] = useState(emptyDraft);
  const [savedDraftKey, setSavedDraftKey] = useState(draftKey(emptyDraft));
  const [loading, setLoading] = useState(true);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState("");
  const [success, setSuccess] = useState("");
  const dirty = editing !== null && draftKey(draft) !== savedDraftKey;

  useUnsavedDraftGuard({
    dirty,
    onSave: save,
    onDiscard: closeEditor
  });

  async function load() {
    setLoading(true);
    setError("");
    try {
      let nextWatermark = getDeltaWatermark("access:system-accounts");
      let nextAccounts = accountsRef.current;
      let nextRoles = rolesRef.current;
      let hasMore = false;
      do {
        const response = await fetchSystemAccountsDelta(settings, { since: nextWatermark });
        const continuingFullSnapshot = response.full && nextWatermark?.startsWith("full:");
        nextAccounts = response.full
          ? continuingFullSnapshot
            ? mergeDeltaRows(nextAccounts, response.accounts, [], (account) => account.account_id, { deletedResourceType: "access_system_account", sort: sortSystemAccounts })
            : response.accounts
          : mergeDeltaRows(nextAccounts, response.accounts, response.deleted, (account) => account.account_id, { deletedResourceType: "access_system_account", sort: sortSystemAccounts });
        nextRoles = response.full
          ? continuingFullSnapshot
            ? mergeDeltaRows(nextRoles, response.roles, [], (role) => role.id, { deletedResourceType: "access_system_role", sort: sortSystemRoles })
            : response.roles
          : mergeDeltaRows(nextRoles, response.roles, response.deleted, (role) => role.id, { deletedResourceType: "access_system_role", sort: sortSystemRoles });
        nextWatermark = response.watermark ?? null;
        hasMore = response.has_more;
      } while (hasMore);
      setDeltaWatermark("access:system-accounts", nextWatermark);
      const nextTenants = await fetchTenants(settings);
      accountsRef.current = nextAccounts;
      rolesRef.current = nextRoles;
      setAccounts(nextAccounts);
      setRoles(nextRoles);
      setTenants(nextTenants);
    } catch (err) {setError(adminErrorMessage(err));} finally
    {setLoading(false);}
  }

  useEffect(() => {
    accountsRef.current = [];
    rolesRef.current = [];
    resetDeltaWatermark();
    void load();
  }, [settings.accessToken, settings.apiBaseUrl, resetDeltaWatermark]);

  function openCreate() {
    setDraft(emptyDraft);
    setSavedDraftKey(draftKey(emptyDraft));
    setEditing("new");
  }

  function openEdit(item: SystemAccountItem) {
    const nextDraft = {
      email: item.email,
      displayName: item.display_name || "",
      password: "",
      passwordResetRequired: false,
      isActive: item.is_active,
      roleIds: item.roles.map((role) => role.id),
      memberships: item.memberships.map((membership) => ({
        tenant_id: membership.tenant_id,
        is_active: membership.is_active,
        role_ids: membership.role_ids || [],
        group_ids: membership.group_ids || [],
        is_owner: membership.is_owner,
        is_last_active_owner: membership.is_last_active_owner
      }))
    };
    setDraft(nextDraft);
    setSavedDraftKey(draftKey(nextDraft));
    setEditing(item);
  }

  function closeEditor() {
    setEditing(null);
    setDraft(emptyDraft);
    setSavedDraftKey(draftKey(emptyDraft));
  }

  function membership(tenantId: string) {
    return draft.memberships.find((item) => item.tenant_id === tenantId);
  }

  function setMembership(tenantId: string, enabled: boolean) {
    setDraft((current) => ({
      ...current,
      memberships: enabled ?
      [...current.memberships.filter((item) => item.tenant_id !== tenantId), { tenant_id: tenantId, is_active: true, role_ids: [], group_ids: [] }] :
      current.memberships.filter((item) => item.tenant_id !== tenantId)
    }));
  }

  async function save(): Promise<boolean> {
    setBusy(true);
    setError("");
    try {
      if (editing === "new") {
        const response = await createSystemAccount(settings, {
          email: draft.email,
          display_name: draft.displayName || null,
          password: draft.password || null,
          password_reset_required: draft.passwordResetRequired,
          is_active: draft.isActive,
          role_ids: canAssignRoles ? draft.roleIds : [],
          memberships: canManageMemberships ? draft.memberships.map(({ tenant_id, is_active, role_ids, group_ids }) => ({ tenant_id, is_active, role_ids, group_ids })) : []
        });
        if (response.temporary_password) setTemporaryPassword({ email: response.account.email, value: response.temporary_password });
        setSuccess(i18nMessage("i18n:govoplan-access.global_account_value_created.5100e467", { value0: response.account.email }));
      } else if (editing) {
        const accountChanges: {display_name?: string | null;is_active?: boolean;} = {};
        if (canUpdate) accountChanges.display_name = draft.displayName || null;
        if (canSuspend) accountChanges.is_active = draft.isActive;
        if (Object.keys(accountChanges).length) await updateSystemAccount(settings, editing.account_id, accountChanges);
        if (canAssignRoles) await updateSystemAccountRoles(settings, editing.account_id, draft.roleIds);
        if (canManageMemberships) await updateSystemMemberships(settings, editing.account_id, draft.memberships.map(({ tenant_id, is_active, role_ids, group_ids }) => ({ tenant_id, is_active, role_ids, group_ids })));
        setSuccess(i18nMessage("i18n:govoplan-access.global_account_value_updated.0de76b0e", { value0: editing.email }));
      }
      setEditing(null);
      await load();
      await onAuthRefresh();
      return true;
    } catch (err) {setError(adminErrorMessage(err));return false;} finally
    {setBusy(false);}
  }

  async function deactivate() {
    if (!deactivating) return;
    setBusy(true);
    setError("");
    try {
      await updateSystemAccount(settings, deactivating.account_id, { is_active: false });
      setSuccess(i18nMessage("i18n:govoplan-access.value_deactivated.ed3d027c", { value0: deactivating.email }));
      setDeactivating(null);
      await load();
      await onAuthRefresh();
    } catch (err) {setError(adminErrorMessage(err));} finally
    {setBusy(false);}
  }

  const columns = useMemo<DataGridColumn<SystemAccountItem>[]>(() => [
  { id: "account", header: "i18n:govoplan-access.account.85dfa32c", width: "minmax(240px, 1.2fr)", minWidth: 210, resizable: true, sticky: "start", sortable: true, filterable: true, value: (row) => `${row.display_name || ""} ${row.email}`, render: (row) => <div><strong>{row.display_name || row.email}</strong><div className="muted small-note">{row.email}</div></div> },
  { id: "tenants", header: "i18n:govoplan-access.tenant_memberships.451de736", width: 280, minWidth: 190, maxWidth: 520, resizable: true, fill: true, sortable: true, filterable: true, value: (row) => row.memberships.map((item) => item.tenant_name).join(", ") || "—" },
  { id: "roles", header: "i18n:govoplan-access.system_roles.a9461aa6", width: 220, minWidth: 170, maxWidth: 420, resizable: true, sortable: true, filterable: true, value: (row) => joinLabels(row.roles) },
  { id: "status", header: "i18n:govoplan-access.status.bae7d5be", width: 120, resizable: false, sortable: true, filterable: true, value: (row) => row.is_active ? "active" : "inactive", render: (row) => <StatusBadge status={row.is_active ? "active" : "inactive"} /> },
  { id: "last_login", header: "i18n:govoplan-access.last_login.43dab84f", width: 180, minWidth: 150, resizable: true, sortable: true, value: (row) => row.last_login_at || "", render: (row) => formatDateTime(row.last_login_at) },
  { id: "actions", header: "i18n:govoplan-access.actions.c3cd636a", width: 150, sticky: "end", resizable: false, align: "right", render: (row) => <div className="admin-icon-actions">
      <AdminIconButton label={i18nMessage("i18n:govoplan-access.inspect_value.9d5d1071", { value0: row.email })} icon={<Search />} onClick={() => setViewing(row)} />
      <AdminIconButton label={i18nMessage("i18n:govoplan-access.edit_value.fad75899", { value0: row.email })} icon={<Pencil />} onClick={() => openEdit(row)} disabled={!(canUpdate || canSuspend || canAssignRoles || canManageMemberships)} />
      <AdminIconButton label={i18nMessage("i18n:govoplan-access.deactivate_value.a276a667", { value0: row.email })} icon={<Trash2 />} variant="danger" onClick={() => setDeactivating(row)} disabled={!canSuspend || !row.is_active || row.memberships.some((membership) => membership.is_last_active_owner)} />
    </div> }],
  [canAssignRoles, canManageMemberships, canSuspend, canUpdate]);

  return (
    <>
      <AdminPageLayout
        title="i18n:govoplan-access.central_users.91ac1b51"
        description="i18n:govoplan-access.global_login_identities_tenant_memberships_and_s.8f963b7f"
        loading={loading}
        error={error}
        success={success}
        actions={<><Button onClick={() => void load()} disabled={loading}>i18n:govoplan-access.reload.cce71553</Button><AdminIconButton label="i18n:govoplan-access.add_global_account.18e4df22" icon={<Plus />} variant="primary" onClick={openCreate} disabled={!canCreate} /></>}>
        
        <div className="admin-table-surface"><DataGrid id="admin-system-users-v3" rows={accounts} columns={columns} initialFit="container" getRowKey={(row) => row.account_id} emptyText="i18n:govoplan-access.no_global_accounts_found.29d96a9e" /></div>
      </AdminPageLayout>

      <Dialog open={editing !== null} title={editing === "new" ? "i18n:govoplan-access.create_global_account.e821f016" : "i18n:govoplan-access.edit_global_account.d13b8485"} onClose={() => !busy && setEditing(null)} className="admin-dialog admin-dialog-wide" footer={<><Button onClick={() => setEditing(null)} disabled={busy}>i18n:govoplan-access.cancel.77dfd213</Button><Button variant="primary" onClick={() => void save()} disabled={busy || !draft.email.trim() || (editing === "new" ? !canCreate : !(canUpdate || canSuspend || canAssignRoles || canManageMemberships))}>{busy ? "i18n:govoplan-access.saving.56a2285c" : "i18n:govoplan-access.save_account.0b761f5c"}</Button></>}>
        <div className="admin-form-grid two-columns">
          <FormField label="i18n:govoplan-access.email.84add5b2"><input value={draft.email} disabled={editing !== "new"} onChange={(event) => setDraft({ ...draft, email: event.target.value })} /></FormField>
          <FormField label="i18n:govoplan-access.display_name.c7874aaa"><input value={draft.displayName} disabled={editing !== "new" && !canUpdate} onChange={(event) => setDraft({ ...draft, displayName: event.target.value })} /></FormField>
          {editing === "new" &&
          <FormField label="i18n:govoplan-access.initial_password.2278be8c">
              <PasswordField
              value={draft.password}
              placeholder="i18n:govoplan-access.leave_empty_to_generate.e58222d8"
              autoComplete="new-password"
              onValueChange={(password) => setDraft({ ...draft, password })} />
            
            </FormField>
          }
          <FormField label="i18n:govoplan-access.account_status.8dd86c6d"><select value={draft.isActive ? "active" : "inactive"} disabled={Boolean(editing && editing !== "new" && (!canSuspend || editing.memberships.some((membership) => membership.is_last_active_owner)))} onChange={(event) => setDraft({ ...draft, isActive: event.target.value === "active" })}><option value="active">i18n:govoplan-access.active.a733b809</option><option value="inactive">i18n:govoplan-access.inactive.09af574c</option></select></FormField>
        </div>
        <div className="admin-assignment-grid">
          <div><span className="form-label">i18n:govoplan-access.system_roles.a9461aa6</span><AdminSelectionList options={roles.map((role) => ({ id: role.id, label: role.name, description: role.description, disabled: !canAssignRoles }))} selected={draft.roleIds} onChange={(roleIds) => setDraft({ ...draft, roleIds })} /></div>
          <div><span className="form-label">i18n:govoplan-access.tenant_memberships.451de736</span><div className="admin-selection-list">{tenants.map((tenant) => <label className="admin-selection-item" key={tenant.id}><input type="checkbox" checked={Boolean(membership(tenant.id))} disabled={!canManageMemberships || Boolean(membership(tenant.id)?.is_last_active_owner)} onChange={(event) => setMembership(tenant.id, event.target.checked)} /><span><strong>{tenant.name}</strong><small>{tenant.slug}</small></span></label>)}</div></div>
        </div>
        {editing && editing !== "new" && editing.memberships.some((membership) => membership.is_last_active_owner) && <p className="admin-protection-note">i18n:govoplan-access.this_account_is_the_last_active_operational_owne.5087839f</p>}
        <p className="muted small-note">i18n:govoplan-access.removing_a_tenant_checkbox_suspends_that_members.7c6df77d</p>
      </Dialog>

      <Dialog open={Boolean(viewing)} title="i18n:govoplan-access.global_account_details.0a0cf240" onClose={() => setViewing(null)} className="admin-dialog admin-dialog-wide" footer={<Button onClick={() => setViewing(null)}>i18n:govoplan-access.close.bbfa773e</Button>}>
        {viewing && <dl className="admin-details-grid"><div><dt>i18n:govoplan-access.account.85dfa32c</dt><dd>{viewing.email}</dd></div><div><dt>i18n:govoplan-access.display_name.c7874aaa</dt><dd>{viewing.display_name || "—"}</dd></div><div><dt>i18n:govoplan-access.status.bae7d5be</dt><dd>{viewing.is_active ? "i18n:govoplan-access.active.a733b809" : "i18n:govoplan-access.inactive.09af574c"}</dd></div><div><dt>i18n:govoplan-access.last_login.43dab84f</dt><dd>{formatDateTime(viewing.last_login_at)}</dd></div><div><dt>i18n:govoplan-access.system_roles.a9461aa6</dt><dd>{joinLabels(viewing.roles)}</dd></div><div><dt>i18n:govoplan-access.tenants.1f7ae776</dt><dd>{viewing.memberships.map((item) => item.tenant_name).join(", ") || "—"}</dd></div></dl>}
      </Dialog>

      <Dialog open={Boolean(temporaryPassword)} title="i18n:govoplan-access.temporary_password.62d60628" onClose={() => setTemporaryPassword(null)} className="admin-dialog" footer={<Button variant="primary" onClick={() => setTemporaryPassword(null)}>i18n:govoplan-access.i_have_recorded_it.7522da18</Button>}>
        {temporaryPassword && <><p>i18n:govoplan-access.this_is_shown_once_for.b0f0f526 <strong>{temporaryPassword.email}</strong>.</p><code className="admin-secret">{temporaryPassword.value}</code></>}
      </Dialog>

      <ConfirmDialog open={Boolean(deactivating)} title="i18n:govoplan-access.deactivate_global_account.66d92736" message={i18nMessage("i18n:govoplan-access.deactivate_value_all_sessions_and_tenant_access_.2024856f", { value0: deactivating?.email })} confirmLabel="i18n:govoplan-access.deactivate_account.fd9fd676" tone="danger" busy={busy} onCancel={() => setDeactivating(null)} onConfirm={() => void deactivate()} />
    </>);

}

function draftKey(draft: typeof emptyDraft): string {
  return JSON.stringify(draft);
}

function sortSystemAccounts(left: SystemAccountItem, right: SystemAccountItem): number {
  return left.email.localeCompare(right.email);
}

function sortSystemRoles(left: RoleSummary, right: RoleSummary): number {
  return left.name.localeCompare(right.name);
}