// *****************************************************************************
// Copyright (C) 2025 EclipseSource GmbH.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// http://www.eclipse.org/legal/epl-2.0.
//
// This Source Code may also be made available under the following Secondary
// Licenses when the conditions for such availability set forth in the Eclipse
// Public License v. 2.0 are satisfied: GNU General Public License, version 2
// with the GNU Classpath Exception which is available at
// https://www.gnu.org/software/classpath/license.html.
//
// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
// *****************************************************************************

import { ToolInvocationContext, ToolProvider, ToolRequest } from '@theia/ai-core';
import { inject, injectable } from '@theia/core/shared/inversify';
import { TerminalService } from '@theia/terminal/lib/browser/base/terminal-service';
import { SUGGEST_TERMINAL_COMMAND_ID } from '../common/ai-terminal-functions';
import { WorkspaceService } from '@theia/workspace/lib/browser';
import { TerminalWidget } from '@theia/terminal/lib/browser/base/terminal-widget';
import { waitForEvent } from '@theia/core/lib/common/promise-util';
import { ApplicationShell } from '@theia/core/lib/browser';

@injectable()
export class SuggestTerminalCommand implements ToolProvider {
    static ID = SUGGEST_TERMINAL_COMMAND_ID;

    @inject(TerminalService)
    protected readonly terminalService: TerminalService;

    @inject(WorkspaceService)
    protected readonly workspaceService: WorkspaceService;

    @inject(ApplicationShell)
    protected readonly applicationShell: ApplicationShell;

    getTool(): ToolRequest {
        return {
            id: SuggestTerminalCommand.ID,
            name: SuggestTerminalCommand.ID,
            description: `Proposes executing a command in the terminal.\n
            This tool will automatically write the command into the terminal buffer.\n
            Execution of the command is up to the user.`,
            parameters: {
                type: 'object',
                properties: {
                    command: {
                        type: 'string',
                        description: `The content of the command to write to the terminal buffer.\n
                        ALWAYS provide the COMPLETE intended content of the command, without any truncation or omissions.\n
                        You MUST include ALL parts of the command.`
                    }
                },
                required: ['command']
            },
            handler: async (args: string, ctx?: ToolInvocationContext): Promise<string> => {
                if (ctx?.cancellationToken?.isCancellationRequested) {
                    return JSON.stringify({ error: 'Operation cancelled by user' });
                }
                // Ensure that there is a workspace
                let activeTerminal: TerminalWidget | undefined = this.terminalService.lastUsedTerminal;
                if (!activeTerminal || activeTerminal.isDisposed) {
                    try {
                        activeTerminal = await this.terminalService.newTerminal({});
                        this.terminalService.open(activeTerminal, { mode: 'activate' });
                        await activeTerminal.start();
                        // Wait until the terminal prompt is emitted
                        await waitForEvent(activeTerminal.onOutput, 3000);
                    } catch (error) {
                        return JSON.stringify({ error: `Error executing tool 'suggestTerminalCommand': ${error}` });
                    }
                } else {
                    this.terminalService.open(activeTerminal, { mode: 'activate' });
                }
                let command: string;
                try {
                    const { command: parsedCommand } = JSON.parse(args);
                    command = parsedCommand;
                } catch (error) {
                    return JSON.stringify({ error: `Error parsing arguments for tool 'suggestTerminalCommand': ${error}` });
                }
                if (!this.isValidCommand(command)) {
                    return JSON.stringify({ error: 'Error validating command generated by \'suggestTerminalCommand\'' });
                };
                // Clear the current input line by sending Ctrl+A (move to start) and Ctrl+K (delete to end)
                activeTerminal.sendText('\x01\x0b');
                activeTerminal.sendText(command);
                return `Proposed executing the terminal command ${command}. The user will review and potentially execute the command.`;
            }
        };
    }

    protected isValidCommand(command: string): boolean {
        // Command should not be empty and should not contain control characters
        const CONTROL_CHAR_REGEX = /[\u0000-\u001F\u007F]/; // ASCII control range
        if (!command || CONTROL_CHAR_REGEX.test(command)) {
            return false;
        }
        return true;
    }
}