import { useCallback, useMemo, useState } from "react";
import { usePolling } from "../hooks/usePolling";
import { fetchRoles } from "../api/client";
import type { RoleInfo } from "../types";
import AsyncPageState from "./ui/AsyncPageState";
import Button from "./ui/Button";
import Chip from "./ui/Chip";
import RoleBadge from "./RoleBadge";
import PageHero from "./ui/PageHero";
import PageSectionCard from "./ui/PageSectionCard";
import SummaryStat from "./ui/SummaryStat";
import StatusDot from "./ui/StatusDot";
import RoleEditor from "./RoleEditor";
import { useI18n } from "../i18n";
import { roleListChangeKey } from "../utils/pollingKeys";

interface RoleStatusProps {
  workspace: string;
}

function getRoleState(role: RoleInfo, copy: ReturnType<typeof useI18n>["copy"]) {
  if (role.pending > 0) {
    return {
      label: copy.roleStatus.states.attention,
      dotClassName: "bg-[color:var(--app-accent-warm)]",
      textClassName: "text-[color:var(--app-accent-warm)]",
    };
  }

  if (role.session) {
    return {
      label: copy.roleStatus.states.active,
      dotClassName: "app-dot-success",
      textClassName: "app-text-success",
    };
  }

  return {
    label: copy.roleStatus.states.idle,
    dotClassName: "app-dot-idle",
    textClassName: "app-text-idle",
  };
}

function getRolePriority(role: RoleInfo) {
  return (role.pending > 0 ? 2 : 0) + (role.session ? 1 : 0);
}

export default function RoleStatus({ workspace }: RoleStatusProps) {
  const { copy, formatAbsoluteDateTime, formatRelativeTime } = useI18n();
  const fetcher = useCallback(() => fetchRoles(workspace), [workspace]);
  const { data, loading, error, refresh } = usePolling<RoleInfo[]>(
    fetcher,
    5000,
    { getChangeKey: roleListChangeKey },
  );

  // Editor state: string = editing role name, undefined = closed
  const [editorTarget, setEditorTarget] = useState<string | undefined>();

  const sortedRoles = useMemo(() => {
    if (!data) return [];
    return [...data].sort((left, right) => {
      if (left.sort_order !== right.sort_order) {
        return left.sort_order - right.sort_order;
      }
      const priorityDiff = getRolePriority(right) - getRolePriority(left);
      if (priorityDiff !== 0) {
        return priorityDiff;
      }
      return left.name.localeCompare(right.name);
    });
  }, [data]);

  const activeSessions = data?.filter((role) => role.session).length ?? 0;
  const attentionCount = data?.filter((role) => role.pending > 0).length ?? 0;
  const idleCount = data ? data.length - activeSessions : 0;
  const waitingMessages = data?.reduce((sum, role) => sum + role.pending, 0) ?? 0;

  return (
    <AsyncPageState
      workspace={workspace}
      workspaceSubject={copy.roleStatus.workspaceSubject}
      loading={loading}
      loadingMode="initial"
      hasData={Boolean(data && data.length > 0)}
      error={error}
      loadingEyebrow={copy.roleStatus.eyebrow}
      loadingTitle={copy.roleStatus.loadingTitle}
      errorEyebrow={copy.roleStatus.eyebrow}
      errorTitle={copy.roleStatus.errorTitle}
      emptyEyebrow={copy.roleStatus.eyebrow}
      emptyTitle={copy.roleStatus.emptyTitle}
      emptyDetail={copy.roleStatus.emptyDetail}
      retryLabel={copy.common.retry}
      onRetry={refresh}
    >
      <div className="space-y-4">
        <PageHero
          eyebrow={copy.roleStatus.eyebrow}
          title={copy.roleStatus.heroTitle}
          stats={
            <div className="grid gap-4 sm:grid-cols-2 lg:min-w-[24rem]">
              <SummaryStat
                label={copy.roleStatus.summary.activeAgents}
                value={activeSessions}
                detail={copy.roleStatus.summary.activeAgentsDetail}
              />
              <SummaryStat
                label={copy.roleStatus.summary.needsAttention}
                value={attentionCount}
                detail={copy.roleStatus.summary.needsAttentionDetail}
                tone="attention"
              />
              <SummaryStat
                label={copy.roleStatus.summary.waitingItems}
                value={waitingMessages}
                detail={copy.roleStatus.summary.waitingItemsDetail}
              />
              <SummaryStat
                label={copy.roleStatus.summary.notStarted}
                value={idleCount}
                detail={copy.roleStatus.summary.notStartedDetail}
                tone="muted"
              />
            </div>
          }
        />

        <PageSectionCard
          title={copy.roleStatus.listTitle}
          detail={copy.roleStatus.listDetail}
          action={<Chip size="sm">{sortedRoles.length}</Chip>}
          className="rounded-[26px]"
          headerClassName="px-4 py-4 sm:px-5"
          bodyClassName="grid gap-3 p-4 sm:p-5 md:grid-cols-2"
        >
          {sortedRoles.map((role) => {
            const state = getRoleState(role, copy);

            return (
              <article
                key={role.name}
                className="app-panel-muted flex h-full flex-col rounded-2xl border border-[color:var(--app-divider-soft)] p-4"
              >
                <div className="flex items-start justify-between gap-3">
                  <div className="min-w-0 flex-1">
                    <div className="flex flex-wrap items-center gap-2">
                      <RoleBadge role={role.name} size="md" />
                      <StatusDot className={`h-2 w-2 ${state.dotClassName}`} />
                      <span className={`app-caption-medium ${state.textClassName}`}>
                        {state.label}
                      </span>
                      {role.pending > 0 && (
                        <Chip tone="attention" className="app-caption-medium">
                          {copy.roleStatus.states.waiting(role.pending)}
                        </Chip>
                      )}
                    </div>

                    <p
                      className="app-text-soft mt-3 text-sm"
                      title={role.description}
                      dir="auto"
                    >
                      {copy.roleStatus.conciseDescription[role.name as keyof typeof copy.roleStatus.conciseDescription] ?? role.description}
                    </p>
                  </div>

                  <Button
                    variant="ghost"
                    size="xs"
                    onClick={() => setEditorTarget(role.name)}
                  >
                    {copy.common.edit}
                  </Button>
                </div>

                {role.session?.last_message ? (
                  <p
                    className="app-text-faint mt-3 line-clamp-3 break-words text-xs leading-6"
                    title={role.session.last_message}
                    dir="auto"
                  >
                    {role.session.last_message}
                  </p>
                ) : null}

                <div className="mt-auto flex items-end justify-between gap-3 pt-4">
                  <div className="min-w-0">
                    <div className="app-text-faint app-caption">{copy.roleStatus.lastActive}</div>
                    {role.session ? (
                      <div
                        className="app-text-primary mt-1 text-sm"
                        title={formatAbsoluteDateTime(role.session.last_used_at)}
                      >
                        {formatRelativeTime(role.session.last_used_at)}
                      </div>
                    ) : (
                      <div className="app-text-idle mt-1 text-sm">{copy.common.notStarted}</div>
                    )}
                  </div>

                  <div className="app-text-faint text-right text-[11px] font-medium uppercase tracking-[0.16em]">
                    #{role.sort_order}
                  </div>
                </div>
              </article>
            );
          })}
        </PageSectionCard>

        {/* Role Editor slide-out panel */}
        {editorTarget !== undefined && (
          <RoleEditor
            workspace={workspace}
            roleName={editorTarget}
            onClose={() => setEditorTarget(undefined)}
            onSaved={() => {
              setEditorTarget(undefined);
              refresh();
            }}
          />
        )}
      </div>
    </AsyncPageState>
  );
}