import React from 'react';

import { Icon } from '@/components/icon/Icon';
import type { IconName } from '@/components/icon/icons';
import { preloadProviderLogos } from '@/hooks/useProviderLogo';
import { useTabletLayout } from '@/lib/device';
import { useI18n } from '@/lib/i18n';
import { clampPercent, resolveUsageTone } from '@/lib/quota';
import { UsageProviderCards } from '@/components/usage/UsageProviderCards';
import { useUsageProviderGroups, type UsageProviderGroup } from '@/components/usage/usageGroups';
import { cn } from '@/lib/utils';
import { useConfigStore } from '@/stores/useConfigStore';
import { useQuotaAutoRefresh, useQuotaStore } from '@/stores/useQuotaStore';
import { useUIStore, type TimeFormatPreference } from '@/stores/useUIStore';
import { useSelectionStore } from '@/sync/selection-store';
import { useSessionMessages } from '@/sync/sync-context';

const TABLET_METADATA_POPOVER_WIDTH = 380;

const getNumericLimit = (limit: unknown, key: 'context' | 'output'): number | undefined => {
  if (!limit || typeof limit !== 'object') return undefined;
  const value = (limit as Partial<Record<'context' | 'output', unknown>>)[key];
  return typeof value === 'number' && Number.isFinite(value) ? value : undefined;
};

const getTokenCount = (value: unknown): number => (
  typeof value === 'number' && Number.isFinite(value) ? value : 0
);

const formatTokens = (value: number): string => {
  if (value >= 1_000_000) return `${(value / 1_000_000).toFixed(1)}M`;
  if (value >= 1_000) return `${(value / 1_000).toFixed(1)}K`;
  return String(value);
};

type ContextDisplay = {
  percentage: number;
  tokens: string;
  colorClass: string;
} | null;

const ContextProgressIcon: React.FC<{ percentage: number }> = ({ percentage }) => {
  const progressPct = clampPercent(percentage) ?? 0;
  const tone = resolveUsageTone(percentage);
  const progressColor = tone === 'critical'
    ? 'var(--status-error)'
    : tone === 'warn'
      ? 'var(--status-warning)'
      : 'var(--status-success)';
  const size = 18;
  const stroke = 3;
  const radius = (size - stroke) / 2;
  const circumference = 2 * Math.PI * radius;

  return (
    <svg
      viewBox={`0 0 ${size} ${size}`}
      className="size-[18px] -rotate-90"
      role="progressbar"
      aria-valuenow={Math.round(progressPct)}
      aria-valuemin={0}
      aria-valuemax={100}
    >
      <circle
        cx={size / 2}
        cy={size / 2}
        r={radius}
        fill="none"
        stroke="var(--interactive-border)"
        strokeWidth={stroke}
      />
      <circle
        cx={size / 2}
        cy={size / 2}
        r={radius}
        fill="none"
        stroke={progressColor}
        strokeWidth={stroke}
        strokeLinecap="round"
        strokeDasharray={circumference}
        strokeDashoffset={circumference * (1 - progressPct / 100)}
        className="transition-[stroke-dashoffset,stroke] duration-300"
      />
    </svg>
  );
};

const MetadataRow: React.FC<{
  icon?: IconName;
  iconNode?: React.ReactNode;
  label: string;
  children: React.ReactNode;
}> = ({ icon, iconNode, label, children }) => (
  <div className="flex min-w-0 items-center gap-3 rounded-xl px-2.5 py-2.5">
    <span className="flex size-5 shrink-0 items-center justify-center text-muted-foreground">
      {iconNode ?? (icon ? <Icon name={icon} className="size-[18px]" /> : null)}
    </span>
    <span className="shrink-0 typography-ui-label text-muted-foreground">{label}</span>
    <span className="min-w-0 flex-1 truncate text-right typography-ui-label font-medium text-foreground">
      {children}
    </span>
  </div>
);

const SessionMetadataOverlay: React.FC<{
  open: boolean;
  onClose: () => void;
  anchorRef: React.RefObject<HTMLElement | null>;
  contextDisplay: ContextDisplay;
  usageGroups: UsageProviderGroup[];
  usageDisplayMode: 'usage' | 'remaining';
  isUsageLoading: boolean;
  timeFormatPreference: TimeFormatPreference;
}> = ({ open, onClose, anchorRef, contextDisplay, usageGroups, usageDisplayMode, isUsageLoading, timeFormatPreference }) => {
  const { t } = useI18n();
  const panelRef = React.useRef<HTMLDivElement>(null);
  const [shouldRender, setShouldRender] = React.useState(open);
  const [isExiting, setIsExiting] = React.useState(false);
  // Tablet: a phone-width sheet stretched across the whole chat column looks
  // broken — render a popover anchored to the metadata button instead.
  const { enabled: isTabletLayout } = useTabletLayout();
  const wrapperRef = React.useRef<HTMLDivElement>(null);
  const [anchorLeft, setIpadAnchorLeft] = React.useState<number | null>(null);

  // The shell has transformed ancestors, so the fixed wrapper's containing
  // block is the chat column, NOT the viewport. Anchor the popover in the
  // wrapper's own coordinate space — viewport-based lefts would double-count
  // the sidebar offset.
  React.useLayoutEffect(() => {
    if (!open || !isTabletLayout || !shouldRender) return;
    const compute = () => {
      const anchorRect = anchorRef.current?.getBoundingClientRect();
      const wrapperRect = wrapperRef.current?.getBoundingClientRect();
      if (!anchorRect || !wrapperRect) {
        setIpadAnchorLeft(null);
        return;
      }
      const relativeLeft = anchorRect.left - wrapperRect.left;
      const left = Math.min(
        Math.max(relativeLeft, 8),
        Math.max(8, wrapperRect.width - TABLET_METADATA_POPOVER_WIDTH - 8),
      );
      setIpadAnchorLeft(left);
    };
    compute();
    // Re-anchor if the chat column shifts while the popover is open (sidebar
    // toggle/resize, orientation change) — the header buttons move with it.
    const wrapper = wrapperRef.current;
    if (typeof ResizeObserver === 'undefined' || !wrapper) return;
    const observer = new ResizeObserver(compute);
    observer.observe(wrapper);
    return () => observer.disconnect();
  }, [anchorRef, isTabletLayout, open, shouldRender]);

  const isPopover = isTabletLayout && anchorLeft !== null;

  React.useEffect(() => {
    if (open) {
      setShouldRender(true);
      setIsExiting(false);
      return;
    }

    if (!shouldRender) return;
    setIsExiting(true);
    const timeoutId = window.setTimeout(() => {
      setShouldRender(false);
      setIsExiting(false);
    }, 140);
    return () => window.clearTimeout(timeoutId);
  }, [open, shouldRender]);

  React.useEffect(() => {
    if (!open) return;
    const handleKey = (event: KeyboardEvent) => {
      if (event.key === 'Escape') onClose();
    };
    document.addEventListener('keydown', handleKey);
    return () => document.removeEventListener('keydown', handleKey);
  }, [onClose, open]);

  React.useEffect(() => {
    if (!open) return;

    const closeIfOutside = (event: PointerEvent | WheelEvent) => {
      const target = event.target;
      if (!(target instanceof Node)) {
        onClose();
        return;
      }
      if (panelRef.current?.contains(target) || anchorRef.current?.contains(target)) return;
      onClose();
    };

    document.addEventListener('pointerdown', closeIfOutside, true);
    document.addEventListener('wheel', closeIfOutside, true);
    return () => {
      document.removeEventListener('pointerdown', closeIfOutside, true);
      document.removeEventListener('wheel', closeIfOutside, true);
    };
  }, [anchorRef, onClose, open]);

  if (!shouldRender) return null;

  return (
    <div ref={wrapperRef} className="fixed inset-x-0 bottom-0 top-[calc(var(--oc-safe-area-top,0px)+var(--oc-header-height,56px))] z-20 pointer-events-none">
      <div
        ref={panelRef}
        role="dialog"
        aria-label={t('mobile.header.openMetadataAria')}
        className={cn(
          'overflow-y-auto overscroll-contain rounded-[20px] border border-border/70 bg-[var(--surface-elevated)] p-2 shadow-[0_12px_32px_rgb(0_0_0_/_0.2)] will-change-transform',
          isPopover ? 'absolute origin-top-left' : 'mx-3 mt-2',
          isExiting ? 'pointer-events-none' : 'pointer-events-auto',
        )}
        style={{
          animation: `${isExiting ? 'session-metadata-out' : 'session-metadata-in'} ${isExiting ? 140 : 170}ms cubic-bezier(0.32, 0.72, 0, 1) forwards`,
          maxHeight: 'min(72dvh, calc(100dvh - var(--oc-safe-area-top, 0px) - var(--oc-header-height, 56px) - 1rem))',
          ...(isPopover
            ? {
                top: 8,
                left: anchorLeft ?? 8,
                width: `min(${TABLET_METADATA_POPOVER_WIDTH}px, calc(100% - 16px))`,
              }
            : null),
        }}
      >
        <div className="space-y-1">
          {contextDisplay ? (
            <MetadataRow
              iconNode={<ContextProgressIcon percentage={contextDisplay.percentage} />}
              label={t('mobile.header.metadata.context')}
            >
              <span className="inline-flex items-baseline gap-1.5 tabular-nums">
                <span className={cn('font-semibold', contextDisplay.colorClass)}>{contextDisplay.percentage.toFixed(1)}%</span>
                <span className="text-muted-foreground">{contextDisplay.tokens}</span>
              </span>
            </MetadataRow>
          ) : null}
          <MobileUsageLimits
            groups={usageGroups}
            displayMode={usageDisplayMode}
            isLoading={isUsageLoading}
            timeFormatPreference={timeFormatPreference}
          />
        </div>
      </div>
      <style>{`
        @keyframes session-metadata-in {
          from { opacity: 0; transform: translateY(-8px) scale(0.985); }
          to { opacity: 1; transform: translateY(0) scale(1); }
        }
        @keyframes session-metadata-out {
          from { opacity: 1; transform: translateY(0) scale(1); }
          to { opacity: 0; transform: translateY(-6px) scale(0.985); }
        }
      `}</style>
    </div>
  );
};

const MobileUsageLimits: React.FC<{
  groups: UsageProviderGroup[];
  displayMode: 'usage' | 'remaining';
  isLoading: boolean;
  timeFormatPreference: TimeFormatPreference;
}> = ({ groups, displayMode, isLoading, timeFormatPreference }) => {
  const { t } = useI18n();
  const modeLabel = displayMode === 'remaining' ? t('header.services.remaining') : t('header.services.used');

  // First open often races the quota fetch (~2s) — show an explicit loading
  // row instead of collapsing to an empty overlay.
  if (groups.length === 0) {
    if (!isLoading) return null;
    return (
      <div className="flex items-center justify-center gap-2 px-2.5 py-6 text-muted-foreground">
        <Icon name="loader-4" className="size-4 animate-spin" aria-hidden />
        <span className="typography-ui-label">{t('common.loading')}</span>
      </div>
    );
  }

  return (
    <div className="pt-2.5">
      <div className="flex min-w-0 items-center gap-3 px-2.5 pb-1.5">
        <span className="flex size-5 shrink-0 items-center justify-center text-muted-foreground">
          <Icon name="timer" className="size-[18px]" />
        </span>
        <span className="shrink-0 typography-ui-label text-muted-foreground">
          {t('mobile.header.metadata.usage')}
        </span>
        <span className="inline-flex min-w-0 flex-1 items-center justify-end gap-1.5 typography-ui-label text-muted-foreground">
          {isLoading ? <Icon name="refresh" className="size-3.5 animate-spin" /> : null}
          <span className="truncate">{modeLabel}</span>
        </span>
      </div>

      <UsageProviderCards
        groups={groups}
        displayMode={displayMode}
        timeFormatPreference={timeFormatPreference}
      />
    </div>
  );
};

export const MobileSessionMetadataButton = React.memo(function MobileSessionMetadataButton({
  open,
  onOpenChange,
  currentSessionId,
  effectiveDirectory,
  isNewSessionDraftOpen,
}: {
  open: boolean;
  onOpenChange: (open: boolean | ((open: boolean) => boolean)) => void;
  currentSessionId: string | null;
  effectiveDirectory: string | null;
  isNewSessionDraftOpen: boolean;
}) {
  const { t } = useI18n();
  const metadataTriggerRef = React.useRef<HTMLButtonElement>(null);
  const activeSessionMessages = useSessionMessages(currentSessionId ?? '', effectiveDirectory || undefined);
  const providers = useConfigStore((state) => state.providers);
  const currentProviderId = useConfigStore((state) => state.currentProviderId);
  const currentModelId = useConfigStore((state) => state.currentModelId);
  const getModelMetadata = useConfigStore((state) => state.getModelMetadata);
  useConfigStore((state) => state.modelsMetadata.size);
  const savedSessionModel = useSelectionStore(
    React.useCallback(
      (state) => (currentSessionId ? state.sessionModelSelections.get(currentSessionId) ?? null : null),
      [currentSessionId],
    ),
  );
  const quotaResults = useQuotaStore((state) => state.results);
  const loadQuotaSettings = useQuotaStore((state) => state.loadSettings);
  const fetchAllQuotas = useQuotaStore((state) => state.fetchAllQuotas);
  const isQuotaLoading = useQuotaStore((state) => state.isLoading);
  const quotaDisplayMode = useQuotaStore((state) => state.displayMode);
  const dropdownProviderIds = useQuotaStore((state) => state.dropdownProviderIds);
  const timeFormatPreference = useUIStore((state) => state.timeFormatPreference);

  useQuotaAutoRefresh();

  React.useEffect(() => {
    void loadQuotaSettings();
  }, [loadQuotaSettings]);

  React.useEffect(() => {
    preloadProviderLogos(dropdownProviderIds);
  }, [dropdownProviderIds]);

  React.useEffect(() => {
    if (!open || isQuotaLoading) return;
    const missingEnabledProvider = dropdownProviderIds.some((providerId) => (
      !quotaResults.some((result) => result.providerId === providerId)
    ));
    if (!missingEnabledProvider) return;
    void fetchAllQuotas();
  }, [dropdownProviderIds, fetchAllQuotas, isQuotaLoading, open, quotaResults]);

  const latestMessageModel = React.useMemo(() => {
    for (let i = activeSessionMessages.length - 1; i >= 0; i -= 1) {
      const message = activeSessionMessages[i] as typeof activeSessionMessages[number] & {
        model?: { providerID?: string; modelID?: string };
      };
      if (message.role !== 'user') continue;
      const providerID = typeof message.model?.providerID === 'string' && message.model.providerID.trim().length > 0
        ? message.model.providerID
        : undefined;
      const modelID = typeof message.model?.modelID === 'string' && message.model.modelID.trim().length > 0
        ? message.model.modelID
        : undefined;
      if (providerID && modelID) return { providerID, modelID };
    }
    return null;
  }, [activeSessionMessages]);

  const modelRef = latestMessageModel
    ?? (savedSessionModel ? { providerID: savedSessionModel.providerId, modelID: savedSessionModel.modelId } : null)
    ?? (currentProviderId && currentModelId ? { providerID: currentProviderId, modelID: currentModelId } : null);
  const provider = modelRef ? providers.find((entry) => entry.id === modelRef.providerID) : undefined;
  const liveModel = provider?.models.find((model) => model.id === modelRef?.modelID);
  const metadata = modelRef ? getModelMetadata(modelRef.providerID, modelRef.modelID) : undefined;
  const contextLimit = getNumericLimit((liveModel as { limit?: unknown } | undefined)?.limit, 'context')
    ?? metadata?.limit?.context
    ?? 0;
  const totalTokens = React.useMemo(() => {
    for (let i = activeSessionMessages.length - 1; i >= 0; i -= 1) {
      const message = activeSessionMessages[i] as typeof activeSessionMessages[number] & {
        tokens?: {
          total?: unknown;
          input?: unknown;
          output?: unknown;
          reasoning?: unknown;
          cache?: { read?: unknown; write?: unknown };
        };
      };
      if (message.role !== 'assistant' || !message.tokens) continue;
      // Multi-step turns accumulate the fields across API round-trips, so
      // summing them overstates the window. The server-reported total is the
      // final round-trip's window; sum only when the server did not send it.
      const reportedTotal = getTokenCount(message.tokens.total);
      if (reportedTotal > 0) return reportedTotal;
      const total = getTokenCount(message.tokens.input)
        + getTokenCount(message.tokens.output)
        + getTokenCount(message.tokens.reasoning)
        + getTokenCount(message.tokens.cache?.read)
        + getTokenCount(message.tokens.cache?.write);
      if (total > 0) return total;
    }
    return 0;
  }, [activeSessionMessages]);

  const contextPercentage =
    !isNewSessionDraftOpen && totalTokens > 0 && contextLimit > 0
      ? Math.min((totalTokens / contextLimit) * 100, 999)
      : null;
  const contextTokens = contextPercentage !== null
    ? `${formatTokens(totalTokens)}/${formatTokens(contextLimit)}`
    : null;
  const contextColorClass =
    contextPercentage === null
      ? ''
      : contextPercentage >= 90
        ? 'text-[var(--status-error)]'
        : contextPercentage >= 75
          ? 'text-[var(--status-warning)]'
          : 'text-[var(--status-success)]';
  const contextDisplay: ContextDisplay = contextPercentage !== null && contextTokens
    ? { percentage: contextPercentage, tokens: contextTokens, colorClass: contextColorClass }
    : null;

  const usageGroups = useUsageProviderGroups();

  React.useEffect(() => {
    if (!open || usageGroups.length === 0) return;
    preloadProviderLogos(usageGroups.map((group) => group.providerId));
  }, [open, usageGroups]);

  return (
    <>
      <button
        ref={metadataTriggerRef}
        type="button"
        className="flex size-10 shrink-0 items-center justify-center rounded-full text-muted-foreground transition-colors hover:bg-interactive-hover hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary"
        aria-label={t('mobile.header.openMetadataAria')}
        aria-expanded={open}
        onClick={() => onOpenChange((currentOpen) => !currentOpen)}
        style={{ touchAction: 'manipulation' }}
      >
        {/* Live context gauge doubles as the metadata trigger: filled by the
            session's context usage, an empty ring on a fresh draft. */}
        <ContextProgressIcon percentage={contextDisplay?.percentage ?? 0} />
      </button>
      <SessionMetadataOverlay
        open={open}
        onClose={() => onOpenChange(false)}
        anchorRef={metadataTriggerRef}
        contextDisplay={contextDisplay}
        usageGroups={usageGroups}
        usageDisplayMode={quotaDisplayMode}
        isUsageLoading={isQuotaLoading}
        timeFormatPreference={timeFormatPreference}
      />
    </>
  );
});