import { useEffect, useMemo, useState } from 'react';

import { api } from '@renderer/api';
import { MemberExecutionLog } from '@renderer/components/team/members/MemberExecutionLog';
import { asEnhancedChunkArray } from '@renderer/types/data';
import { AlertCircle, Clock, FileText, Loader2 } from 'lucide-react';

import type {
  BoardTaskLogActor,
  BoardTaskLogSegment,
  BoardTaskLogStreamResponse,
} from '@shared/types';

interface TaskLogStreamSectionProps {
  teamName: string;
  taskId: string;
}

function formatRelativeTime(isoString: string): string {
  const date = new Date(isoString);
  const diffMs = Date.now() - date.getTime();
  const diffMin = Math.floor(diffMs / 60_000);
  const diffHours = Math.floor(diffMin / 60);
  const diffDays = Math.floor(diffHours / 24);

  if (!Number.isFinite(diffMs)) return '--';
  if (diffMin < 1) return 'just now';
  if (diffMin < 60) return `${diffMin}m ago`;
  if (diffHours < 24) return `${diffHours}h ago`;
  return `${diffDays}d ago`;
}

function actorLabel(actor: BoardTaskLogActor): string {
  if (actor.memberName) {
    return actor.memberName;
  }
  if (actor.role === 'lead' || actor.isSidechain === false) {
    return 'lead session';
  }
  if (actor.agentId) {
    return `member ${actor.agentId.slice(0, 8)}`;
  }
  return `member session ${actor.sessionId.slice(0, 8)}`;
}

function normalizeResponse(response: BoardTaskLogStreamResponse): BoardTaskLogStreamResponse {
  return {
    participants: response.participants,
    defaultFilter: response.defaultFilter,
    segments: response.segments.map((segment) => ({
      ...segment,
      chunks: asEnhancedChunkArray(segment.chunks) ?? [],
    })),
  };
}

function SegmentMarker({ segment }: { segment: BoardTaskLogSegment }): React.JSX.Element {
  return (
    <div className="mb-2 flex items-center gap-2 text-[10px] text-[var(--color-text-muted)]">
      <span className="rounded-full border border-[var(--color-border)] px-2 py-0.5 font-medium text-[var(--color-text-secondary)]">
        {actorLabel(segment.actor)}
      </span>
      <span className="flex items-center gap-1">
        <Clock size={10} />
        {formatRelativeTime(segment.endTimestamp)}
      </span>
    </div>
  );
}

function SegmentBlock({
  segment,
  showHeader,
}: {
  segment: BoardTaskLogSegment;
  showHeader: boolean;
}): React.JSX.Element {
  return (
    <div className="min-w-0 overflow-hidden">
      {showHeader ? <SegmentMarker segment={segment} /> : null}
      <MemberExecutionLog chunks={segment.chunks} memberName={segment.actor.memberName} />
    </div>
  );
}

export function TaskLogStreamSection({
  teamName,
  taskId,
}: TaskLogStreamSectionProps): React.JSX.Element {
  const [stream, setStream] = useState<BoardTaskLogStreamResponse | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [selectedParticipantKey, setSelectedParticipantKey] = useState<'all' | string>('all');

  useEffect(() => {
    let cancelled = false;

    const run = async (): Promise<void> => {
      try {
        setLoading(true);
        setError(null);
        const response = normalizeResponse(await api.teams.getTaskLogStream(teamName, taskId));
        if (cancelled) return;
        setStream(response);
        setSelectedParticipantKey(response.defaultFilter);
      } catch (loadError) {
        if (cancelled) return;
        setError(loadError instanceof Error ? loadError.message : 'Failed to load task log stream');
        setStream(null);
      } finally {
        if (!cancelled) {
          setLoading(false);
        }
      }
    };

    void run();
    return () => {
      cancelled = true;
    };
  }, [taskId, teamName]);

  const participants = stream?.participants ?? [];
  const showChips = participants.length > 1;
  const visibleSegments = useMemo(() => {
    const source = stream?.segments ?? [];
    const filtered =
      selectedParticipantKey === 'all'
        ? source
        : source.filter((segment) => segment.participantKey === selectedParticipantKey);
    return [...filtered].reverse();
  }, [selectedParticipantKey, stream?.segments]);

  const showSegmentHeaders =
    participants.length > 1 || (selectedParticipantKey !== 'all' && visibleSegments.length > 1);

  if (loading) {
    return (
      <div className="space-y-2">
        <h4 className="text-xs font-semibold uppercase tracking-[0.2em] text-[var(--color-text-muted)]">
          Task Log Stream
        </h4>
        <div className="flex items-center gap-2 py-4 text-xs text-[var(--color-text-muted)]">
          <Loader2 size={12} className="animate-spin" />
          Loading task log stream...
        </div>
      </div>
    );
  }

  if (error) {
    return (
      <div className="space-y-2">
        <h4 className="text-xs font-semibold uppercase tracking-[0.2em] text-[var(--color-text-muted)]">
          Task Log Stream
        </h4>
        <div className="flex items-center gap-2 py-4 text-xs text-red-400">
          <AlertCircle size={14} />
          {error}
        </div>
      </div>
    );
  }

  return (
    <div className="space-y-3">
      <h4 className="text-xs font-semibold uppercase tracking-[0.2em] text-[var(--color-text-muted)]">
        Task Log Stream
      </h4>
      <p className="text-xs text-[var(--color-text-muted)]">
        Task-scoped transcript logs rendered with the same execution-log components used in Logs.
      </p>

      {showChips ? (
        <div className="flex flex-wrap items-center gap-1.5">
          <button
            type="button"
            className={`rounded-full border px-2.5 py-1 text-[11px] transition-colors ${
              selectedParticipantKey === 'all'
                ? 'bg-[var(--color-accent)]/10 border-[var(--color-accent)] text-[var(--color-text)]'
                : 'border-[var(--color-border)] text-[var(--color-text-muted)] hover:text-[var(--color-text)]'
            }`}
            onClick={() => setSelectedParticipantKey('all')}
          >
            All
          </button>
          {participants.map((participant) => (
            <button
              key={participant.key}
              type="button"
              className={`rounded-full border px-2.5 py-1 text-[11px] transition-colors ${
                selectedParticipantKey === participant.key
                  ? 'bg-[var(--color-accent)]/10 border-[var(--color-accent)] text-[var(--color-text)]'
                  : 'border-[var(--color-border)] text-[var(--color-text-muted)] hover:text-[var(--color-text)]'
              }`}
              onClick={() => setSelectedParticipantKey(participant.key)}
            >
              {participant.label}
            </button>
          ))}
        </div>
      ) : null}

      {visibleSegments.length === 0 ? (
        <div className="py-8 text-center text-xs text-[var(--color-text-muted)]">
          <FileText size={20} className="mx-auto mb-2 opacity-40" />
          No task log stream yet
          <p className="mt-1 text-[10px] opacity-60">
            Task-linked transcript logs will appear here when explicit task-linked transcript
            metadata is available.
          </p>
        </div>
      ) : (
        <div className="space-y-6">
          {visibleSegments.map((segment) => (
            <SegmentBlock key={segment.id} segment={segment} showHeader={showSegmentHeaders} />
          ))}
        </div>
      )}
    </div>
  );
}