/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import React from 'react';
import { Box, type DOMElement } from 'ink';
import { ShellInputPrompt } from '../ShellInputPrompt.js';
import { StickyHeader } from '../StickyHeader.js';
import { useUIActions } from '../../contexts/UIActionsContext.js';
import { useMouseClick } from '../../hooks/useMouseClick.js';
import { ToolResultDisplay } from './ToolResultDisplay.js';
import {
  ToolStatusIndicator,
  ToolInfo,
  TrailingIndicator,
  isThisShellFocusable as checkIsShellFocusable,
  isThisShellFocused as checkIsShellFocused,
  useFocusHint,
  FocusHint,
} from './ToolShared.js';
import type { ToolMessageProps } from './ToolMessage.js';
import { ACTIVE_SHELL_MAX_LINES } from '../../constants.js';
import { useAlternateBuffer } from '../../hooks/useAlternateBuffer.js';
import { useUIState } from '../../contexts/UIStateContext.js';
import { useToolActions } from '../../contexts/ToolActionsContext.js';
import {
  type Config,
  ShellExecutionService,
  CoreToolCallStatus,
} from '@google/gemini-cli-core';
import {
  calculateShellMaxLines,
  calculateToolContentMaxLines,
  SHELL_CONTENT_OVERHEAD,
} from '../../utils/toolLayoutUtils.js';

export interface ShellToolMessageProps extends ToolMessageProps {
  config?: Config;
  isExpandable?: boolean;
}

export const ShellToolMessage: React.FC<ShellToolMessageProps> = ({
  callId,
  name,
  description,
  resultDisplay,
  status,
  availableTerminalHeight,
  terminalWidth,
  emphasis = 'medium',
  renderOutputAsMarkdown = true,
  ptyId,
  config,
  isFirst,
  borderColor,
  borderDimColor,
  isExpandable,
  originalRequestName,
}) => {
  const { isExpanded: isExpandedInContext } = useToolActions();

  const isExpanded =
    (isExpandedInContext ? isExpandedInContext(callId) : false) ||
    availableTerminalHeight === undefined;

  const {
    activePtyId: activeShellPtyId,
    embeddedShellFocused,
    constrainHeight,
  } = useUIState();
  const isAlternateBuffer = useAlternateBuffer();

  const isThisShellFocused = checkIsShellFocused(
    name,
    status,
    ptyId,
    activeShellPtyId,
    embeddedShellFocused,
  );

  const maxLines = calculateShellMaxLines({
    status,
    isAlternateBuffer,
    isThisShellFocused,
    availableTerminalHeight,
    constrainHeight,
    isExpandable,
  });

  const availableHeight = calculateToolContentMaxLines({
    availableTerminalHeight,
    isAlternateBuffer,
    maxLinesLimit: maxLines,
  });

  React.useEffect(() => {
    const isExecuting = status === CoreToolCallStatus.Executing;
    if (isExecuting && ptyId) {
      try {
        const childWidth = terminalWidth - 4; // account for padding and borders
        const finalHeight =
          availableHeight ?? ACTIVE_SHELL_MAX_LINES - SHELL_CONTENT_OVERHEAD;

        ShellExecutionService.resizePty(
          ptyId,
          Math.max(1, childWidth),
          Math.max(1, finalHeight),
        );
      } catch (e) {
        if (
          !(
            e instanceof Error &&
            e.message.includes('Cannot resize a pty that has already exited')
          )
        ) {
          throw e;
        }
      }
    }
  }, [ptyId, status, terminalWidth, availableHeight]);

  const { setEmbeddedShellFocused } = useUIActions();
  const wasFocusedRef = React.useRef(false);

  React.useEffect(() => {
    if (isThisShellFocused) {
      wasFocusedRef.current = true;
    } else if (wasFocusedRef.current) {
      if (embeddedShellFocused) {
        setEmbeddedShellFocused(false);
      }
      wasFocusedRef.current = false;
    }
  }, [isThisShellFocused, embeddedShellFocused, setEmbeddedShellFocused]);

  const headerRef = React.useRef<DOMElement>(null);
  const contentRef = React.useRef<DOMElement>(null);

  // The shell is focusable if it's the shell command, it's executing, and the interactive shell is enabled.
  const isThisShellFocusable = checkIsShellFocusable(name, status, config);

  const handleFocus = () => {
    if (isThisShellFocusable) {
      setEmbeddedShellFocused(true);
    }
  };

  useMouseClick(headerRef, handleFocus, { isActive: !!isThisShellFocusable });
  useMouseClick(contentRef, handleFocus, { isActive: !!isThisShellFocusable });

  const { shouldShowFocusHint } = useFocusHint(
    isThisShellFocusable,
    isThisShellFocused,
    resultDisplay,
  );

  return (
    <>
      <StickyHeader
        width={terminalWidth}
        isFirst={isFirst}
        borderColor={borderColor}
        borderDimColor={borderDimColor}
        containerRef={headerRef}
      >
        <ToolStatusIndicator
          status={status}
          name={name}
          isFocused={isThisShellFocused}
        />

        <ToolInfo
          name={name}
          status={status}
          description={description}
          emphasis={emphasis}
          originalRequestName={originalRequestName}
          isExpanded={isExpanded}
        />

        <FocusHint
          shouldShowFocusHint={shouldShowFocusHint}
          isThisShellFocused={isThisShellFocused}
        />

        {emphasis === 'high' && <TrailingIndicator />}
      </StickyHeader>

      <Box
        ref={contentRef}
        width={terminalWidth}
        borderStyle="round"
        borderColor={borderColor}
        borderDimColor={borderDimColor}
        borderTop={false}
        borderBottom={false}
        borderLeft={true}
        borderRight={true}
        paddingX={1}
        flexDirection="column"
      >
        <ToolResultDisplay
          resultDisplay={resultDisplay}
          availableTerminalHeight={availableTerminalHeight}
          terminalWidth={terminalWidth}
          renderOutputAsMarkdown={renderOutputAsMarkdown}
          hasFocus={isThisShellFocused}
          maxLines={maxLines}
        />
        {isThisShellFocused && config && (
          <ShellInputPrompt
            activeShellPtyId={activeShellPtyId ?? null}
            focus={embeddedShellFocused}
            scrollPageSize={availableTerminalHeight ?? ACTIVE_SHELL_MAX_LINES}
          />
        )}
      </Box>
    </>
  );
};