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

import { useCallback, useEffect, useMemo, useState, useRef } from 'react';
import {
  Box,
  DOMElement,
  measureElement,
  Static,
  Text,
  useInput,
  type Key as InkKeyType,
} from 'ink';
import { StreamingState, type HistoryItem, MessageType } from './types.js';
import { useTerminalSize } from './hooks/useTerminalSize.js';
import { useGeminiStream } from './hooks/useGeminiStream.js';
import { useLoadingIndicator } from './hooks/useLoadingIndicator.js';
import { useThemeCommand } from './hooks/useThemeCommand.js';
import { useSlashCommandProcessor } from './hooks/slashCommandProcessor.js';
import { useAutoAcceptIndicator } from './hooks/useAutoAcceptIndicator.js';
import { useConsoleMessages } from './hooks/useConsoleMessages.js';
import { Header } from './components/Header.js';
import { LoadingIndicator } from './components/LoadingIndicator.js';
import { AutoAcceptIndicator } from './components/AutoAcceptIndicator.js';
import { ShellModeIndicator } from './components/ShellModeIndicator.js';
import { InputPrompt } from './components/InputPrompt.js';
import { Footer } from './components/Footer.js';
import { ThemeDialog } from './components/ThemeDialog.js';
import { Colors } from './colors.js';
import { Help } from './components/Help.js';
import { loadHierarchicalGeminiMemory } from '../config/config.js';
import { LoadedSettings } from '../config/settings.js';
import { Tips } from './components/Tips.js';
import { useConsolePatcher } from './components/ConsolePatcher.js';
import { DetailedMessagesDisplay } from './components/DetailedMessagesDisplay.js';
import { HistoryItemDisplay } from './components/HistoryItemDisplay.js';
import { ContextSummaryDisplay } from './components/ContextSummaryDisplay.js';
import { useHistory } from './hooks/useHistoryManager.js';
import process from 'node:process';
import {
  getErrorMessage,
  type Config,
  getCurrentGeminiMdFilename,
  ApprovalMode,
} from '@gemini-code/core';
import { useLogger } from './hooks/useLogger.js';
import { StreamingContext } from './contexts/StreamingContext.js';
import { useGitBranchName } from './hooks/useGitBranchName.js';

const CTRL_C_PROMPT_DURATION_MS = 1000;

interface AppProps {
  config: Config;
  settings: LoadedSettings;
  cliVersion: string;
  startupWarnings?: string[];
}

export const App = ({
  config,
  settings,
  cliVersion,
  startupWarnings = [],
}: AppProps) => {
  const { history, addItem, clearItems } = useHistory();
  const {
    consoleMessages,
    handleNewMessage,
    clearConsoleMessages: clearConsoleMessagesState,
  } = useConsoleMessages();
  const [staticNeedsRefresh, setStaticNeedsRefresh] = useState(false);
  const [staticKey, setStaticKey] = useState(0);
  const refreshStatic = useCallback(() => {
    setStaticKey((prev) => prev + 1);
  }, [setStaticKey]);

  const [geminiMdFileCount, setGeminiMdFileCount] = useState<number>(0);
  const [debugMessage, setDebugMessage] = useState<string>('');
  const [showHelp, setShowHelp] = useState<boolean>(false);
  const [themeError, setThemeError] = useState<string | null>(null);
  const [footerHeight, setFooterHeight] = useState<number>(0);
  const [corgiMode, setCorgiMode] = useState(false);
  const [shellModeActive, setShellModeActive] = useState(false);
  const [showErrorDetails, setShowErrorDetails] = useState<boolean>(false);
  const [ctrlCPressedOnce, setCtrlCPressedOnce] = useState(false);
  const ctrlCTimerRef = useRef<NodeJS.Timeout | null>(null);

  const errorCount = useMemo(
    () => consoleMessages.filter((msg) => msg.type === 'error').length,
    [consoleMessages],
  );

  useInput((input: string, key: InkKeyType) => {
    if (key.ctrl && input === 'o') {
      setShowErrorDetails((prev) => !prev);
      refreshStatic();
    } else if (key.ctrl && (input === 'c' || input === 'C')) {
      if (ctrlCPressedOnce) {
        if (ctrlCTimerRef.current) {
          clearTimeout(ctrlCTimerRef.current);
        }
        process.exit(0);
      } else {
        setCtrlCPressedOnce(true);
        ctrlCTimerRef.current = setTimeout(() => {
          setCtrlCPressedOnce(false);
          ctrlCTimerRef.current = null;
        }, CTRL_C_PROMPT_DURATION_MS);
      }
    }
  });

  useEffect(
    () => () => {
      if (ctrlCTimerRef.current) {
        clearTimeout(ctrlCTimerRef.current);
      }
    },
    [],
  );

  useConsolePatcher({
    onNewMessage: handleNewMessage,
    debugMode: config.getDebugMode(),
  });

  const toggleCorgiMode = useCallback(() => {
    setCorgiMode((prev) => !prev);
  }, []);

  const {
    isThemeDialogOpen,
    openThemeDialog,
    handleThemeSelect,
    handleThemeHighlight,
  } = useThemeCommand(settings, setThemeError, addItem);

  useEffect(() => {
    if (config) {
      setGeminiMdFileCount(config.getGeminiMdFileCount());
    }
  }, [config]);

  const performMemoryRefresh = useCallback(async () => {
    addItem(
      {
        type: MessageType.INFO,
        text: 'Refreshing hierarchical memory (GEMINI.md files)...',
      },
      Date.now(),
    );
    try {
      const { memoryContent, fileCount } = await loadHierarchicalGeminiMemory(
        process.cwd(),
        config.getDebugMode(),
      );
      config.setUserMemory(memoryContent);
      config.setGeminiMdFileCount(fileCount);
      setGeminiMdFileCount(fileCount);

      addItem(
        {
          type: MessageType.INFO,
          text: `Memory refreshed successfully. ${memoryContent.length > 0 ? `Loaded ${memoryContent.length} characters from ${fileCount} file(s).` : 'No memory content found.'}`,
        },
        Date.now(),
      );
      if (config.getDebugMode()) {
        console.log(
          `[DEBUG] Refreshed memory content in config: ${memoryContent.substring(0, 200)}...`,
        );
      }
    } catch (error) {
      const errorMessage = getErrorMessage(error);
      addItem(
        {
          type: MessageType.ERROR,
          text: `Error refreshing memory: ${errorMessage}`,
        },
        Date.now(),
      );
      console.error('Error refreshing memory:', error);
    }
  }, [config, addItem]);

  const { handleSlashCommand, slashCommands } = useSlashCommandProcessor(
    config,
    addItem,
    clearItems,
    refreshStatic,
    setShowHelp,
    setDebugMessage,
    openThemeDialog,
    performMemoryRefresh,
    toggleCorgiMode,
    cliVersion,
  );

  const { streamingState, submitQuery, initError, pendingHistoryItems } =
    useGeminiStream(
      config.getGeminiClient(),
      addItem,
      setShowHelp,
      config,
      setDebugMessage,
      handleSlashCommand,
      shellModeActive,
    );
  const { elapsedTime, currentLoadingPhrase } =
    useLoadingIndicator(streamingState);
  const showAutoAcceptIndicator = useAutoAcceptIndicator({ config });

  const handleFinalSubmit = useCallback(
    (submittedValue: string) => {
      const trimmedValue = submittedValue.trim();
      if (trimmedValue.length > 0) {
        submitQuery(trimmedValue);
      }
    },
    [submitQuery],
  );

  const logger = useLogger();
  const [userMessages, setUserMessages] = useState<string[]>([]);

  useEffect(() => {
    const fetchUserMessages = async () => {
      const pastMessagesRaw = (await logger?.getPreviousUserMessages()) || []; // Newest first

      const currentSessionUserMessages = history
        .filter(
          (item): item is HistoryItem & { type: 'user'; text: string } =>
            item.type === 'user' &&
            typeof item.text === 'string' &&
            item.text.trim() !== '',
        )
        .map((item) => item.text)
        .reverse(); // Newest first, to match pastMessagesRaw sorting

      // Combine, with current session messages being more recent
      const combinedMessages = [
        ...currentSessionUserMessages,
        ...pastMessagesRaw,
      ];

      // Deduplicate consecutive identical messages from the combined list (still newest first)
      const deduplicatedMessages: string[] = [];
      if (combinedMessages.length > 0) {
        deduplicatedMessages.push(combinedMessages[0]); // Add the newest one unconditionally
        for (let i = 1; i < combinedMessages.length; i++) {
          if (combinedMessages[i] !== combinedMessages[i - 1]) {
            deduplicatedMessages.push(combinedMessages[i]);
          }
        }
      }
      // Reverse to oldest first for useInputHistory
      setUserMessages(deduplicatedMessages.reverse());
    };
    fetchUserMessages();
  }, [history, logger]);

  const isInputActive = streamingState === StreamingState.Idle && !initError;

  const handleClearScreen = useCallback(() => {
    clearItems();
    clearConsoleMessagesState();
    console.clear();
    refreshStatic();
  }, [clearItems, clearConsoleMessagesState, refreshStatic]);

  const { rows: terminalHeight } = useTerminalSize();
  const mainControlsRef = useRef<DOMElement>(null);
  const pendingHistoryItemRef = useRef<DOMElement>(null);

  useEffect(() => {
    if (mainControlsRef.current) {
      const fullFooterMeasurement = measureElement(mainControlsRef.current);
      setFooterHeight(fullFooterMeasurement.height);
    }
  }, [terminalHeight, consoleMessages, showErrorDetails]);

  const availableTerminalHeight = useMemo(() => {
    const staticExtraHeight = /* margins and padding */ 3;
    return terminalHeight - footerHeight - staticExtraHeight;
  }, [terminalHeight, footerHeight]);

  useEffect(() => {
    if (!pendingHistoryItems.length) {
      return;
    }

    const pendingItemDimensions = measureElement(
      pendingHistoryItemRef.current!,
    );

    // If our pending history item happens to exceed the terminal height we will most likely need to refresh
    // our static collection to ensure no duplication or tearing. This is currently working around a core bug
    // in Ink which we have a PR out to fix: https://github.com/vadimdemedes/ink/pull/717
    if (pendingItemDimensions.height > availableTerminalHeight) {
      setStaticNeedsRefresh(true);
    }
  }, [pendingHistoryItems.length, availableTerminalHeight, streamingState]);

  useEffect(() => {
    if (streamingState === StreamingState.Idle && staticNeedsRefresh) {
      setStaticNeedsRefresh(false);
      refreshStatic();
    }
  }, [streamingState, refreshStatic, staticNeedsRefresh]);

  const filteredConsoleMessages = useMemo(() => {
    if (config.getDebugMode()) {
      return consoleMessages;
    }
    return consoleMessages.filter((msg) => msg.type !== 'debug');
  }, [consoleMessages, config]);

  const branchName = useGitBranchName(config.getTargetDir());

  return (
    <StreamingContext.Provider value={streamingState}>
      <Box flexDirection="column" marginBottom={1} width="90%">
        {/*
         * The Static component is an Ink intrinsic in which there can only be 1 per application.
         * Because of this restriction we're hacking it slightly by having a 'header' item here to
         * ensure that it's statically rendered.
         *
         * Background on the Static Item: Anything in the Static component is written a single time
         * to the console. Think of it like doing a console.log and then never using ANSI codes to
         * clear that content ever again. Effectively it has a moving frame that every time new static
         * content is set it'll flush content to the terminal and move the area which it's "clearing"
         * down a notch. Without Static the area which gets erased and redrawn continuously grows.
         */}
        <Static
          key={staticKey}
          items={[
            <Box flexDirection="column" key="header">
              <Header title={process.env.GEMINI_CLI_TITLE} />
              <Tips config={config} />
            </Box>,
            ...history.map((h) => (
              <HistoryItemDisplay
                availableTerminalHeight={availableTerminalHeight}
                key={h.id}
                item={h}
                isPending={false}
              />
            )),
          ]}
        >
          {(item) => item}
        </Static>
        <Box ref={pendingHistoryItemRef}>
          {pendingHistoryItems.map((item, i) => (
            <HistoryItemDisplay
              key={i}
              availableTerminalHeight={availableTerminalHeight}
              // TODO(taehykim): It seems like references to ids aren't necessary in
              // HistoryItemDisplay. Refactor later. Use a fake id for now.
              item={{ ...item, id: 0 }}
              isPending={true}
            />
          ))}
        </Box>
        {showHelp && <Help commands={slashCommands} />}

        <Box flexDirection="column" ref={mainControlsRef}>
          {startupWarnings.length > 0 && (
            <Box
              borderStyle="round"
              borderColor={Colors.AccentYellow}
              paddingX={1}
              marginY={1}
              flexDirection="column"
            >
              {startupWarnings.map((warning, index) => (
                <Text key={index} color={Colors.AccentYellow}>
                  {warning}
                </Text>
              ))}
            </Box>
          )}

          {isThemeDialogOpen ? (
            <Box flexDirection="column">
              {themeError && (
                <Box marginBottom={1}>
                  <Text color={Colors.AccentRed}>{themeError}</Text>
                </Box>
              )}
              <ThemeDialog
                onSelect={handleThemeSelect}
                onHighlight={handleThemeHighlight}
                settings={settings}
              />
            </Box>
          ) : (
            <>
              <LoadingIndicator
                currentLoadingPhrase={
                  config.getAccessibility()?.disableLoadingPhrases
                    ? undefined
                    : currentLoadingPhrase
                }
                elapsedTime={elapsedTime}
              />
              <Box
                marginTop={1}
                display="flex"
                justifyContent="space-between"
                width="100%"
              >
                <Box>
                  {process.env.GEMINI_SYSTEM_MD && (
                    <Text color={Colors.AccentRed}>|⌐■_■| </Text>
                  )}
                  {ctrlCPressedOnce ? (
                    <Text color={Colors.AccentYellow}>
                      Press Ctrl+C again to exit.
                    </Text>
                  ) : (
                    <ContextSummaryDisplay
                      geminiMdFileCount={geminiMdFileCount}
                      contextFileName={
                        settings.merged.contextFileName ||
                        getCurrentGeminiMdFilename()
                      }
                      mcpServers={config.getMcpServers()}
                    />
                  )}
                </Box>
                <Box>
                  {showAutoAcceptIndicator !== ApprovalMode.DEFAULT &&
                    !shellModeActive && (
                      <AutoAcceptIndicator
                        approvalMode={showAutoAcceptIndicator}
                      />
                    )}
                  {shellModeActive && <ShellModeIndicator />}
                </Box>
              </Box>

              {showErrorDetails && (
                <DetailedMessagesDisplay messages={filteredConsoleMessages} />
              )}

              {isInputActive && (
                <InputPrompt
                  widthFraction={0.9}
                  onSubmit={handleFinalSubmit}
                  userMessages={userMessages}
                  onClearScreen={handleClearScreen}
                  config={config}
                  slashCommands={slashCommands}
                  shellModeActive={shellModeActive}
                  setShellModeActive={setShellModeActive}
                />
              )}
            </>
          )}

          {initError && streamingState !== StreamingState.Responding && (
            <Box
              borderStyle="round"
              borderColor={Colors.AccentRed}
              paddingX={1}
              marginBottom={1}
            >
              {history.find(
                (item) =>
                  item.type === 'error' && item.text?.includes(initError),
              )?.text ? (
                <Text color={Colors.AccentRed}>
                  {
                    history.find(
                      (item) =>
                        item.type === 'error' && item.text?.includes(initError),
                    )?.text
                  }
                </Text>
              ) : (
                <>
                  <Text color={Colors.AccentRed}>
                    Initialization Error: {initError}
                  </Text>
                  <Text color={Colors.AccentRed}>
                    {' '}
                    Please check API key and configuration.
                  </Text>
                </>
              )}
            </Box>
          )}

          <Footer
            model={config.getModel()}
            targetDir={config.getTargetDir()}
            debugMode={config.getDebugMode()}
            branchName={branchName}
            debugMessage={debugMessage}
            corgiMode={corgiMode}
            errorCount={errorCount}
            showErrorDetails={showErrorDetails}
            showMemoryUsage={
              config.getDebugMode() || config.getShowMemoryUsage()
            }
          />
        </Box>
      </Box>
    </StreamingContext.Provider>
  );
};