/**
 * @license
 * Copyright 2026 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import { useState, useEffect, useMemo } from 'react';
import { Box, Text, useIsScreenReaderEnabled } from 'ink';
import {
  ApprovalMode,
  checkExhaustive,
  CoreToolCallStatus,
} from '@google/gemini-cli-core';
import { LoadingIndicator } from './LoadingIndicator.js';
import { StatusDisplay } from './StatusDisplay.js';
import { ToastDisplay, shouldShowToast } from './ToastDisplay.js';
import { ApprovalModeIndicator } from './ApprovalModeIndicator.js';
import { ShellModeIndicator } from './ShellModeIndicator.js';
import { DetailedMessagesDisplay } from './DetailedMessagesDisplay.js';
import { RawMarkdownIndicator } from './RawMarkdownIndicator.js';
import { ShortcutsHint } from './ShortcutsHint.js';
import { ShortcutsHelp } from './ShortcutsHelp.js';
import { InputPrompt } from './InputPrompt.js';
import { Footer } from './Footer.js';
import { ShowMoreLines } from './ShowMoreLines.js';
import { QueuedMessageDisplay } from './QueuedMessageDisplay.js';
import { ContextUsageDisplay } from './ContextUsageDisplay.js';
import { HorizontalLine } from './shared/HorizontalLine.js';
import { OverflowProvider } from '../contexts/OverflowContext.js';
import { isNarrowWidth } from '../utils/isNarrowWidth.js';
import { useUIState } from '../contexts/UIStateContext.js';
import { useUIActions } from '../contexts/UIActionsContext.js';
import { useVimMode } from '../contexts/VimModeContext.js';
import { useConfig } from '../contexts/ConfigContext.js';
import { useSettings } from '../contexts/SettingsContext.js';
import { useAlternateBuffer } from '../hooks/useAlternateBuffer.js';
import { StreamingState, type HistoryItemToolGroup } from '../types.js';
import { ConfigInitDisplay } from '../components/ConfigInitDisplay.js';
import { TodoTray } from './messages/Todo.js';
import { getInlineThinkingMode } from '../utils/inlineThinkingMode.js';
import { isContextUsageHigh } from '../utils/contextUsage.js';
import { theme } from '../semantic-colors.js';

export const Composer = ({ isFocused = true }: { isFocused?: boolean }) => {
  const config = useConfig();
  const settings = useSettings();
  const isScreenReaderEnabled = useIsScreenReaderEnabled();
  const uiState = useUIState();
  const uiActions = useUIActions();
  const { vimEnabled, vimMode } = useVimMode();
  const inlineThinkingMode = getInlineThinkingMode(settings);
  const terminalWidth = uiState.terminalWidth;
  const isNarrow = isNarrowWidth(terminalWidth);
  const debugConsoleMaxHeight = Math.floor(Math.max(terminalWidth * 0.2, 5));
  const [suggestionsVisible, setSuggestionsVisible] = useState(false);

  const isAlternateBuffer = useAlternateBuffer();
  const { showApprovalModeIndicator } = uiState;
  const showUiDetails = uiState.cleanUiDetailsVisible;
  const suggestionsPosition = isAlternateBuffer ? 'above' : 'below';
  const hideContextSummary =
    suggestionsVisible && suggestionsPosition === 'above';

  const hasPendingToolConfirmation = useMemo(
    () =>
      (uiState.pendingHistoryItems ?? [])
        .filter(
          (item): item is HistoryItemToolGroup => item.type === 'tool_group',
        )
        .some((item) =>
          item.tools.some(
            (tool) => tool.status === CoreToolCallStatus.AwaitingApproval,
          ),
        ),
    [uiState.pendingHistoryItems],
  );

  const hasPendingActionRequired =
    hasPendingToolConfirmation ||
    Boolean(uiState.commandConfirmationRequest) ||
    Boolean(uiState.authConsentRequest) ||
    (uiState.confirmUpdateExtensionRequests?.length ?? 0) > 0 ||
    Boolean(uiState.loopDetectionConfirmationRequest) ||
    Boolean(uiState.quota.proQuotaRequest) ||
    Boolean(uiState.quota.validationRequest) ||
    Boolean(uiState.customDialog);
  const isPassiveShortcutsHelpState =
    uiState.isInputActive &&
    uiState.streamingState === StreamingState.Idle &&
    !hasPendingActionRequired;

  const { setShortcutsHelpVisible } = uiActions;

  useEffect(() => {
    if (uiState.shortcutsHelpVisible && !isPassiveShortcutsHelpState) {
      setShortcutsHelpVisible(false);
    }
  }, [
    uiState.shortcutsHelpVisible,
    isPassiveShortcutsHelpState,
    setShortcutsHelpVisible,
  ]);

  const showShortcutsHelp =
    uiState.shortcutsHelpVisible &&
    uiState.streamingState === StreamingState.Idle &&
    !hasPendingActionRequired;
  const hasToast = shouldShowToast(uiState);
  const showLoadingIndicator =
    (!uiState.embeddedShellFocused || uiState.isBackgroundShellVisible) &&
    uiState.streamingState === StreamingState.Responding &&
    !hasPendingActionRequired;
  const hideUiDetailsForSuggestions =
    suggestionsVisible && suggestionsPosition === 'above';
  const showApprovalIndicator =
    !uiState.shellModeActive && !hideUiDetailsForSuggestions;
  const showRawMarkdownIndicator = !uiState.renderMarkdown;
  let modeBleedThrough: { text: string; color: string } | null = null;
  switch (showApprovalModeIndicator) {
    case ApprovalMode.YOLO:
      modeBleedThrough = { text: 'YOLO', color: theme.status.error };
      break;
    case ApprovalMode.PLAN:
      modeBleedThrough = { text: 'plan', color: theme.status.success };
      break;
    case ApprovalMode.AUTO_EDIT:
      modeBleedThrough = { text: 'auto edit', color: theme.status.warning };
      break;
    case ApprovalMode.DEFAULT:
      modeBleedThrough = null;
      break;
    default:
      checkExhaustive(showApprovalModeIndicator);
      modeBleedThrough = null;
      break;
  }

  const hideMinimalModeHintWhileBusy =
    !showUiDetails && (showLoadingIndicator || hasPendingActionRequired);
  const minimalModeBleedThrough = hideMinimalModeHintWhileBusy
    ? null
    : modeBleedThrough;
  const hasMinimalStatusBleedThrough = shouldShowToast(uiState);

  const showMinimalContextBleedThrough =
    !settings.merged.ui.footer.hideContextPercentage &&
    isContextUsageHigh(
      uiState.sessionStats.lastPromptTokenCount,
      typeof uiState.currentModel === 'string'
        ? uiState.currentModel
        : undefined,
    );
  const hideShortcutsHintForSuggestions = hideUiDetailsForSuggestions;
  const isModelIdle = uiState.streamingState === StreamingState.Idle;
  const isBufferEmpty = uiState.buffer.text.length === 0;
  const canShowShortcutsHint =
    isModelIdle && isBufferEmpty && !hasPendingActionRequired;
  const [showShortcutsHintDebounced, setShowShortcutsHintDebounced] =
    useState(canShowShortcutsHint);

  useEffect(() => {
    if (!canShowShortcutsHint) {
      setShowShortcutsHintDebounced(false);
      return;
    }

    const timeout = setTimeout(() => {
      setShowShortcutsHintDebounced(true);
    }, 200);

    return () => clearTimeout(timeout);
  }, [canShowShortcutsHint]);

  const shouldReserveSpaceForShortcutsHint =
    settings.merged.ui.showShortcutsHint && !hideShortcutsHintForSuggestions;
  const showShortcutsHint =
    shouldReserveSpaceForShortcutsHint && showShortcutsHintDebounced;
  const showMinimalModeBleedThrough =
    !hideUiDetailsForSuggestions && Boolean(minimalModeBleedThrough);
  const showMinimalInlineLoading = !showUiDetails && showLoadingIndicator;
  const showMinimalBleedThroughRow =
    !showUiDetails &&
    (showMinimalModeBleedThrough ||
      hasMinimalStatusBleedThrough ||
      showMinimalContextBleedThrough);
  const showMinimalMetaRow =
    !showUiDetails &&
    (showMinimalInlineLoading ||
      showMinimalBleedThroughRow ||
      shouldReserveSpaceForShortcutsHint);

  return (
    <Box
      flexDirection="column"
      width={uiState.terminalWidth}
      flexGrow={0}
      flexShrink={0}
    >
      {(!uiState.slashCommands ||
        !uiState.isConfigInitialized ||
        uiState.isResuming) && (
        <ConfigInitDisplay
          message={uiState.isResuming ? 'Resuming session...' : undefined}
        />
      )}

      {showUiDetails && (
        <QueuedMessageDisplay messageQueue={uiState.messageQueue} />
      )}

      {showUiDetails && <TodoTray />}

      <Box width="100%" flexDirection="column">
        <Box
          width="100%"
          flexDirection={isNarrow ? 'column' : 'row'}
          alignItems={isNarrow ? 'flex-start' : 'center'}
          justifyContent={isNarrow ? 'flex-start' : 'space-between'}
        >
          <Box
            marginLeft={1}
            marginRight={isNarrow ? 0 : 1}
            flexDirection="row"
            alignItems={isNarrow ? 'flex-start' : 'center'}
            flexGrow={1}
          >
            {showUiDetails && showLoadingIndicator && (
              <LoadingIndicator
                inline
                thought={
                  uiState.streamingState ===
                  StreamingState.WaitingForConfirmation
                    ? undefined
                    : uiState.thought
                }
                currentLoadingPhrase={
                  settings.merged.ui.loadingPhrases === 'off'
                    ? undefined
                    : uiState.currentLoadingPhrase
                }
                thoughtLabel={
                  inlineThinkingMode === 'full' ? 'Thinking...' : undefined
                }
                elapsedTime={uiState.elapsedTime}
              />
            )}
          </Box>
          <Box
            marginTop={isNarrow ? 1 : 0}
            flexDirection="column"
            alignItems={isNarrow ? 'flex-start' : 'flex-end'}
            minHeight={
              showUiDetails && shouldReserveSpaceForShortcutsHint ? 1 : 0
            }
          >
            {showUiDetails && showShortcutsHint && <ShortcutsHint />}
          </Box>
        </Box>
        {showMinimalMetaRow && (
          <Box
            justifyContent="space-between"
            width="100%"
            flexDirection={isNarrow ? 'column' : 'row'}
            alignItems={isNarrow ? 'flex-start' : 'center'}
          >
            <Box
              marginLeft={1}
              marginRight={isNarrow ? 0 : 1}
              flexDirection="row"
              alignItems={isNarrow ? 'flex-start' : 'center'}
              flexGrow={1}
            >
              {showMinimalInlineLoading && (
                <LoadingIndicator
                  inline
                  thought={
                    uiState.streamingState ===
                    StreamingState.WaitingForConfirmation
                      ? undefined
                      : uiState.thought
                  }
                  currentLoadingPhrase={
                    settings.merged.ui.loadingPhrases === 'off'
                      ? undefined
                      : uiState.currentLoadingPhrase
                  }
                  thoughtLabel={
                    inlineThinkingMode === 'full' ? 'Thinking...' : undefined
                  }
                  elapsedTime={uiState.elapsedTime}
                />
              )}
              {showMinimalModeBleedThrough && minimalModeBleedThrough && (
                <Text color={minimalModeBleedThrough.color}>
                  ● {minimalModeBleedThrough.text}
                </Text>
              )}
              {hasMinimalStatusBleedThrough && (
                <Box
                  marginLeft={
                    showMinimalInlineLoading || showMinimalModeBleedThrough
                      ? 1
                      : 0
                  }
                >
                  <ToastDisplay />
                </Box>
              )}
            </Box>
            {(showMinimalContextBleedThrough ||
              shouldReserveSpaceForShortcutsHint) && (
              <Box
                marginTop={isNarrow && showMinimalBleedThroughRow ? 1 : 0}
                flexDirection={isNarrow ? 'column' : 'row'}
                alignItems={isNarrow ? 'flex-start' : 'flex-end'}
                minHeight={1}
              >
                {showMinimalContextBleedThrough && (
                  <ContextUsageDisplay
                    promptTokenCount={uiState.sessionStats.lastPromptTokenCount}
                    model={uiState.currentModel}
                    terminalWidth={uiState.terminalWidth}
                  />
                )}
                <Box
                  marginLeft={
                    showMinimalContextBleedThrough && !isNarrow ? 1 : 0
                  }
                  marginTop={showMinimalContextBleedThrough && isNarrow ? 1 : 0}
                >
                  {showShortcutsHint && <ShortcutsHint />}
                </Box>
              </Box>
            )}
          </Box>
        )}
        {showShortcutsHelp && <ShortcutsHelp />}
        {showUiDetails && <HorizontalLine />}
        {showUiDetails && (
          <Box
            justifyContent={
              settings.merged.ui.hideContextSummary
                ? 'flex-start'
                : 'space-between'
            }
            width="100%"
            flexDirection={isNarrow ? 'column' : 'row'}
            alignItems={isNarrow ? 'flex-start' : 'center'}
          >
            <Box
              marginLeft={1}
              marginRight={isNarrow ? 0 : 1}
              flexDirection="row"
              alignItems="center"
              flexGrow={1}
            >
              {hasToast ? (
                <ToastDisplay />
              ) : (
                <Box
                  flexDirection={isNarrow ? 'column' : 'row'}
                  alignItems={isNarrow ? 'flex-start' : 'center'}
                >
                  {showApprovalIndicator && (
                    <ApprovalModeIndicator
                      approvalMode={showApprovalModeIndicator}
                      allowPlanMode={uiState.allowPlanMode}
                    />
                  )}
                  {!showLoadingIndicator && (
                    <>
                      {uiState.shellModeActive && (
                        <Box
                          marginLeft={
                            showApprovalIndicator && !isNarrow ? 1 : 0
                          }
                          marginTop={showApprovalIndicator && isNarrow ? 1 : 0}
                        >
                          <ShellModeIndicator />
                        </Box>
                      )}
                      {showRawMarkdownIndicator && (
                        <Box
                          marginLeft={
                            (showApprovalIndicator ||
                              uiState.shellModeActive) &&
                            !isNarrow
                              ? 1
                              : 0
                          }
                          marginTop={
                            (showApprovalIndicator ||
                              uiState.shellModeActive) &&
                            !isNarrow
                              ? 1
                              : 0
                          }
                        >
                          <RawMarkdownIndicator />
                        </Box>
                      )}
                    </>
                  )}
                </Box>
              )}
            </Box>

            <Box
              marginTop={isNarrow ? 1 : 0}
              flexDirection="column"
              alignItems={isNarrow ? 'flex-start' : 'flex-end'}
            >
              {!showLoadingIndicator && (
                <StatusDisplay hideContextSummary={hideContextSummary} />
              )}
            </Box>
          </Box>
        )}
      </Box>

      {showUiDetails && uiState.showErrorDetails && (
        <OverflowProvider>
          <Box flexDirection="column">
            <DetailedMessagesDisplay
              messages={uiState.filteredConsoleMessages}
              maxHeight={
                uiState.constrainHeight ? debugConsoleMaxHeight : undefined
              }
              width={uiState.terminalWidth}
              hasFocus={uiState.showErrorDetails}
            />
            <ShowMoreLines constrainHeight={uiState.constrainHeight} />
          </Box>
        </OverflowProvider>
      )}

      {uiState.isInputActive && (
        <InputPrompt
          buffer={uiState.buffer}
          inputWidth={uiState.inputWidth}
          suggestionsWidth={uiState.suggestionsWidth}
          onSubmit={uiActions.handleFinalSubmit}
          userMessages={uiState.userMessages}
          setBannerVisible={uiActions.setBannerVisible}
          onClearScreen={uiActions.handleClearScreen}
          config={config}
          slashCommands={uiState.slashCommands || []}
          commandContext={uiState.commandContext}
          shellModeActive={uiState.shellModeActive}
          setShellModeActive={uiActions.setShellModeActive}
          approvalMode={showApprovalModeIndicator}
          onEscapePromptChange={uiActions.onEscapePromptChange}
          focus={isFocused}
          vimHandleInput={uiActions.vimHandleInput}
          isEmbeddedShellFocused={uiState.embeddedShellFocused}
          popAllMessages={uiActions.popAllMessages}
          placeholder={
            vimEnabled
              ? vimMode === 'INSERT'
                ? "  Press 'Esc' for NORMAL mode."
                : "  Press 'i' for INSERT mode."
              : uiState.shellModeActive
                ? '  Type your shell command'
                : '  Type your message or @path/to/file'
          }
          setQueueErrorMessage={uiActions.setQueueErrorMessage}
          streamingState={uiState.streamingState}
          suggestionsPosition={suggestionsPosition}
          onSuggestionsVisibilityChange={setSuggestionsVisible}
        />
      )}

      {showUiDetails &&
        !settings.merged.ui.hideFooter &&
        !isScreenReaderEnabled && <Footer />}
    </Box>
  );
};