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

import type React from 'react';
import { Box, Text } from 'ink';
import { Colors } from '../colors.js';
import type { SlashCommand } from '../commands/types.js';
import { KEYBOARD_SHORTCUTS_URL } from '../constants.js';
import { getBorderStyle } from '../contexts/UnicodeRenderingContext.js';

interface HelpProps {
  commands: readonly SlashCommand[];
}

const BasicsSection: React.FC = () => (
  <>
    <Text bold color={Colors.Foreground}>
      Basics:
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Add context
      </Text>
      : Use{' '}
      <Text bold color={Colors.AccentPurple}>
        @
      </Text>{' '}
      to specify files for context (e.g.,{' '}
      <Text bold color={Colors.AccentPurple}>
        @src/myFile.ts
      </Text>
      ) to target specific files or folders.
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Shell mode
      </Text>
      : Execute shell commands via{' '}
      <Text bold color={Colors.AccentPurple}>
        !
      </Text>{' '}
      (e.g.,{' '}
      <Text bold color={Colors.AccentPurple}>
        !npm run start
      </Text>
      ) or use natural language (e.g.{' '}
      <Text bold color={Colors.AccentPurple}>
        start server
      </Text>
      ).
    </Text>
  </>
);

interface CommandsSectionProps {
  commands: readonly SlashCommand[];
}

const CommandsSection: React.FC<CommandsSectionProps> = ({ commands }) => (
  <>
    <Text bold color={Colors.Foreground}>
      Commands:
    </Text>
    {commands
      .filter((command) => command.description)
      .map((command: SlashCommand) => (
        <Box key={command.name} flexDirection="column">
          <Text color={Colors.Foreground}>
            <Text bold color={Colors.AccentPurple}>
              {' '}
              /{command.name}
            </Text>
            {command.description && ' - ' + command.description}
          </Text>
          {command.subCommands?.map((subCommand) => (
            <Text key={subCommand.name} color={Colors.Foreground}>
              <Text bold color={Colors.AccentPurple}>
                {'   '}
                {subCommand.name}
              </Text>
              {subCommand.description && ' - ' + subCommand.description}
            </Text>
          ))}
        </Box>
      ))}
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        {' '}
        !{' '}
      </Text>
      - shell command
    </Text>
  </>
);

/**
 * On Windows the console reports Ctrl+Enter and Ctrl+J as the same byte, so the
 * newline key is labelled Ctrl+Enter there and inserts a newline while the
 * agent is idle, or while streaming when there is nothing to steer (empty
 * input and no queued messages) — see issue #2951.
 */
function newlineShortcutDescription(platform: NodeJS.Platform): string {
  if (platform === 'win32')
    return '- New line (while idle, or when there is nothing to steer)';
  if (platform === 'linux')
    return '- New line (Alt+Enter works for certain linux distros)';
  return '- New line';
}

const KeyboardShortcutsPart1: React.FC = () => (
  <>
    <Text bold color={Colors.Foreground}>
      Keyboard Shortcuts:
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Alt+Left/Right
      </Text>{' '}
      - Jump through words in the input
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Ctrl+C
      </Text>{' '}
      - Quit application
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        {process.platform === 'win32' ? 'Ctrl+Enter' : 'Ctrl+J'}
      </Text>{' '}
      {newlineShortcutDescription(process.platform)}
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Ctrl+L
      </Text>{' '}
      - Clear the screen
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Ctrl+\
      </Text>{' '}
      - Toggle mouse tracking
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Ctrl+X
      </Text>{' '}
      - Open input in external editor
    </Text>
  </>
);

const KeyboardShortcutsPart2: React.FC = () => (
  <>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Ctrl+Y
      </Text>{' '}
      - Toggle YOLO mode
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Enter
      </Text>{' '}
      - Send message
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Ctrl+Enter
      </Text>{' '}
      - Steer the agent (or the queued messages) while it is responding
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Esc
      </Text>{' '}
      - Cancel operation / Clear input (double press)
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Shift+Tab
      </Text>{' '}
      - Toggle auto-accepting edits
    </Text>
    <Text color={Colors.Foreground}>
      <Text bold color={Colors.AccentPurple}>
        Up/Down
      </Text>{' '}
      - Cycle through your prompt history
    </Text>
    <Box height={1} />
    <Text color={Colors.Foreground}>
      For a full list of shortcuts, see{' '}
      <Text bold color={Colors.AccentPurple}>
        {KEYBOARD_SHORTCUTS_URL}
      </Text>
    </Text>
  </>
);

const KeyboardShortcutsSection: React.FC = () => (
  <>
    <KeyboardShortcutsPart1 />
    <KeyboardShortcutsPart2 />
  </>
);

export const Help: React.FC<HelpProps> = ({ commands }) => (
  <Box
    flexDirection="column"
    marginBottom={1}
    borderColor={Colors.Gray}
    borderStyle={getBorderStyle('round')}
    padding={1}
  >
    <BasicsSection />
    <Box height={1} />
    <CommandsSection commands={commands} />
    <Box height={1} />
    <KeyboardShortcutsSection />
  </Box>
);