import React, { memo, useEffect, useRef, useState } from 'react';
import { createPortal } from 'react-dom';

import { useAppTranslation } from '@features/localization/renderer';
import {
  CARD_ICON_MUTED,
  CARD_SEPARATOR,
  CARD_TEXT_LIGHT,
  COLOR_TEXT_MUTED,
  TAG_BG,
  TAG_BORDER,
  TAG_TEXT,
} from '@renderer/constants/cssVariables';
import { formatTokensCompact } from '@renderer/utils/formatters';

// =============================================================================
// Types
// =============================================================================
import type { PhaseTokenBreakdown } from '@renderer/types/data';

interface MetricsPillProps {
  mainSessionImpact?: {
    callTokens: number;
    resultTokens: number;
    totalTokens: number;
  };
  lastUsage?: {
    input_tokens: number;
    output_tokens: number;
    cache_read_input_tokens?: number;
    cache_creation_input_tokens?: number;
  };
  /** Label override for the right segment (e.g. "Context Window" for team members) */
  isolatedLabel?: string;
  /** Override isolated total (for multi-phase total consumption) */
  isolatedOverride?: number;
  /** Phase breakdown for tooltip (shown when multiple phases exist) */
  phaseBreakdown?: PhaseTokenBreakdown[];
}

// =============================================================================
// Unified Metrics Pill - Compact monospace pill with tooltip
// =============================================================================

export const MetricsPill = memo(
  ({
    mainSessionImpact,
    lastUsage,
    isolatedLabel,
    isolatedOverride,
    phaseBreakdown,
  }: Readonly<MetricsPillProps>): React.ReactElement | null => {
    const { t } = useAppTranslation('common');
    const [showTooltip, setShowTooltip] = useState(false);
    const [tooltipStyle, setTooltipStyle] = useState<React.CSSProperties>({});
    const containerRef = useRef<HTMLDivElement>(null);
    const hideTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);

    const hasMainImpact = mainSessionImpact && mainSessionImpact.totalTokens > 0;
    const hasIsolated =
      isolatedOverride != null
        ? isolatedOverride > 0
        : lastUsage && lastUsage.input_tokens + lastUsage.output_tokens > 0;

    const isolatedTotal =
      isolatedOverride ??
      (lastUsage
        ? lastUsage.input_tokens +
          lastUsage.output_tokens +
          (lastUsage.cache_read_input_tokens ?? 0) +
          (lastUsage.cache_creation_input_tokens ?? 0)
        : 0);

    const hasPhases = phaseBreakdown && phaseBreakdown.length > 1;

    const clearHideTimeout = (): void => {
      if (hideTimeoutRef.current) {
        clearTimeout(hideTimeoutRef.current);
        hideTimeoutRef.current = null;
      }
    };

    const handleMouseEnter = (): void => {
      clearHideTimeout();
      setShowTooltip(true);
    };

    const handleMouseLeave = (): void => {
      clearHideTimeout();
      hideTimeoutRef.current = setTimeout(() => setShowTooltip(false), 100);
    };

    useEffect(() => {
      if (showTooltip && containerRef.current) {
        const rect = containerRef.current.getBoundingClientRect();
        const tooltipWidth = 220;
        let left = rect.left + rect.width / 2 - tooltipWidth / 2;
        if (left < 8) left = 8;
        if (left + tooltipWidth > window.innerWidth - 8) {
          left = window.innerWidth - tooltipWidth - 8;
        }
        setTooltipStyle({
          position: 'fixed',
          bottom: window.innerHeight - rect.top + 6,
          left,
          width: tooltipWidth,
          zIndex: 99999,
        });
      }
    }, [showTooltip]);

    useEffect(() => {
      if (!showTooltip) return;
      const handleScroll = (): void => setShowTooltip(false);
      window.addEventListener('scroll', handleScroll, true);
      return () => window.removeEventListener('scroll', handleScroll, true);
    }, [showTooltip]);

    useEffect(() => {
      return () => clearHideTimeout();
    }, []);

    if (!hasMainImpact && !hasIsolated) {
      return null;
    }

    const mainValue = hasMainImpact ? formatTokensCompact(mainSessionImpact.totalTokens) : null;
    const isolatedValue = hasIsolated ? formatTokensCompact(isolatedTotal) : null;
    const rightLabel = isolatedLabel ?? 'Subagent Context';

    return (
      <>
        <div
          ref={containerRef}
          role="tooltip"
          className="inline-flex cursor-default items-center gap-1 rounded px-1.5 py-0.5 font-mono text-[11px]"
          style={{
            backgroundColor: TAG_BG,
            border: `1px solid ${TAG_BORDER}`,
            color: TAG_TEXT,
          }}
          onMouseEnter={handleMouseEnter}
          onMouseLeave={handleMouseLeave}
        >
          {mainValue && <span className="tabular-nums">{mainValue}</span>}
          {mainValue && isolatedValue && <span style={{ color: CARD_SEPARATOR }}>|</span>}
          {isolatedValue && <span className="tabular-nums">{isolatedValue}</span>}
        </div>

        {showTooltip &&
          createPortal(
            <div
              role="tooltip"
              className="rounded-md bg-surface-overlay p-2 text-[11px] shadow-xl"
              style={{
                ...tooltipStyle,
                border: `1px solid ${TAG_BORDER}`,
              }}
              onMouseEnter={handleMouseEnter}
              onMouseLeave={handleMouseLeave}
            >
              <div className="space-y-1">
                {hasMainImpact && (
                  <div className="flex items-center justify-between gap-3">
                    <span style={{ color: COLOR_TEXT_MUTED }}>
                      {t('chat.subagent.metrics.mainContext')}
                    </span>
                    <span className="font-mono tabular-nums" style={{ color: CARD_TEXT_LIGHT }}>
                      {mainSessionImpact.totalTokens.toLocaleString()}
                    </span>
                  </div>
                )}
                {hasIsolated && (
                  <div className="flex items-center justify-between gap-3">
                    <span style={{ color: COLOR_TEXT_MUTED }}>{rightLabel}</span>
                    <span className="font-mono tabular-nums" style={{ color: CARD_TEXT_LIGHT }}>
                      {isolatedTotal.toLocaleString()}
                    </span>
                  </div>
                )}
                {hasPhases &&
                  phaseBreakdown.map((phase) => (
                    <div
                      key={phase.phaseNumber}
                      className="flex items-center justify-between gap-3 pl-2"
                    >
                      <span className="text-[10px]" style={{ color: CARD_ICON_MUTED }}>
                        {t('chat.subagent.metrics.phase', { phase: phase.phaseNumber })}
                      </span>
                      <span
                        className="font-mono text-[10px] tabular-nums"
                        style={{ color: CARD_ICON_MUTED }}
                      >
                        {formatTokensCompact(phase.peakTokens)}
                        {phase.postCompaction != null && (
                          <span style={{ color: '#4ade80' }}>
                            {' '}
                            → {formatTokensCompact(phase.postCompaction)}
                          </span>
                        )}
                      </span>
                    </div>
                  ))}
                <div
                  className="mt-1 pt-1.5 text-[10px]"
                  style={{ borderTop: `1px solid ${TAG_BORDER}`, color: CARD_ICON_MUTED }}
                >
                  {hasMainImpact && hasIsolated
                    ? 'Left: parent injection · Right: internal'
                    : hasMainImpact
                      ? 'Tokens injected to parent'
                      : 'Internal token usage'}
                </div>
              </div>
            </div>,
            document.body
          )}
      </>
    );
  }
);

MetricsPill.displayName = 'MetricsPill';