"""
Terminal/Bash Execution Tool - Execute shell commands with safety constraints

Language support: bash, sh, zsh, powershell (OS-dependent)
"""

import asyncio
import logging
import os
import shlex
from dataclasses import dataclass
from typing import Any, Dict, List, Optional

logger = logging.getLogger(__name__)

# Whitelist of allowed commands for security
ALLOWED_COMMANDS = {
    "npm": {"allowed_args": ["install", "run", "build", "test", "start", "init", "update", "outdated"]},
    "yarn": {"allowed_args": ["install", "run", "build", "test", "start", "init"]},
    "pip": {"allowed_args": ["install", "uninstall", "list", "show", "freeze", "requirements"]},
    "pip3": {"allowed_args": ["install", "uninstall", "list", "show", "freeze", "requirements"]},
    "python": {"allowed_args": ["-m", "-c", "-v", "--version"]},
    "python3": {"allowed_args": ["-m", "-c", "-v", "--version"]},
    "git": {"allowed_args": ["clone", "commit", "push", "pull", "status", "log", "branch", "checkout", "add", "diff", "merge", "fetch", "remote"]},
    "docker": {"allowed_args": ["build", "run", "ps", "stop", "start", "rm", "images", "pull", "push"]},
    "curl": {"allowed_args": []},  # Allow curl for API requests and downloads
    "wget": {"allowed_args": []},
    "node": {"allowed_args": ["-v", "--version"]},
    "cat": {"allowed_args": []},
    "grep": {"allowed_args": ["-r", "-n", "-i", "-v", "-E"]},
    "find": {"allowed_args": ["-name", "-type", "-size", "-mtime"]},
    "ls": {"allowed_args": ["-la", "-l", "-a", "-h"]},
    "cd": {"allowed_args": []},
    "mkdir": {"allowed_args": ["-p"]},
    "cp": {"allowed_args": ["-r", "-f"]},
    "mv": {"allowed_args": []},
    "echo": {"allowed_args": []},
    "env": {"allowed_args": []},
    "which": {"allowed_args": []},
    "pwd": {"allowed_args": []},
    "touch": {"allowed_args": []},
    "head": {"allowed_args": ["-n"]},
    "tail": {"allowed_args": ["-n", "-f"]},
    "sort": {"allowed_args": []},
    "uniq": {"allowed_args": []},
    "wc": {"allowed_args": ["-l", "-w", "-c"]},
    "tar": {"allowed_args": ["-czf", "-xzf", "-cvf", "-xvf"]},
    "zip": {"allowed_args": ["-r"]},
    "unzip": {"allowed_args": []},
}

# Commands that are completely disabled
DISABLED_COMMANDS = {
    "sudo", "su", "rm", "rmdir", "mkfs", "fdisk", "dd", "format",
    "shutdown", "reboot", "halt", "poweroff", "kill", "pkill",
    "chmod", "chown", "chgrp", "passwd", "useradd", "userdel",
}


@dataclass
class TerminalResult:
    """Result of a terminal command execution"""
    exit_code: int
    stdout: str
    stderr: str
    success: bool
    command: str
    duration_ms: float


class TerminalExecutor:
    """
    Execute shell commands with safety constraints.
    """
    
    def __init__(self, cwd: Optional[str] = None, env_vars: Optional[Dict[str, str]] = None):
        self.cwd = cwd or os.getcwd()
        self.env_vars = {**os.environ, **(env_vars or {})}
    
    def _validate_command(self, command: str) -> tuple[bool, Optional[str]]:
        """
        Validate that the command is safe to execute.
        Returns (is_valid, error_message)
        """
        # Check for dangerous patterns
        dangerous_patterns = [
            ";", "&&", "||", "|", ">", "<", "`", "$()",
        ]
        
        # Split command to get base command
        parts = shlex.split(command)
        if not parts:
            return False, "Empty command"
        
        base_cmd = parts[0]
        
        # Check if command is disabled
        if base_cmd in DISABLED_COMMANDS:
            return False, f"Command '{base_cmd}' is disabled for security reasons"
        
        # Check if command is in whitelist
        if base_cmd not in ALLOWED_COMMANDS:
            return False, f"Command '{base_cmd}' is not in the allowed list"
        
        # Check for shell operators that could be dangerous
        for pattern in dangerous_patterns:
            if pattern in command and pattern not in [">>", "<<"]:
                # Allow some safe redirects but warn about others
                if pattern in ["|", ";", "&&", "||"]:
                    return False, f"Shell operators like '{pattern}' are not allowed for security"
        
        return True, None
    
    async def execute_command(
        self,
        command: str,
        timeout: int = 30,
        sandbox: bool = True
    ) -> TerminalResult:
        """
        Execute terminal command with:
        - Timeout protection (prevent hanging)
        - Output streaming (see results in real-time)
        - Error capture (stderr + exit codes)
        - Working directory context
        - Environment variable injection
        """
        start_time = asyncio.get_event_loop().time()
        
        # Validate command if sandbox mode
        if sandbox:
            is_valid, error_msg = self._validate_command(command)
            if not is_valid:
                return TerminalResult(
                    exit_code=-1,
                    stdout="",
                    stderr=error_msg,
                    success=False,
                    command=command,
                    duration_ms=0
                )
        
        try:
            # Execute with streaming output
            process = await asyncio.create_subprocess_shell(
                command,
                stdout=asyncio.subprocess.PIPE,
                stderr=asyncio.subprocess.PIPE,
                cwd=self.cwd,
                env=self.env_vars
            )
            
            try:
                stdout, stderr = await asyncio.wait_for(
                    process.communicate(),
                    timeout=timeout
                )
                
                duration_ms = (asyncio.get_event_loop().time() - start_time) * 1000
                
                return TerminalResult(
                    exit_code=process.returncode,
                    stdout=stdout.decode('utf-8', errors='replace'),
                    stderr=stderr.decode('utf-8', errors='replace'),
                    success=process.returncode == 0,
                    command=command,
                    duration_ms=duration_ms
                )
            
            except asyncio.TimeoutError:
                process.kill()
                await process.wait()
                
                duration_ms = (asyncio.get_event_loop().time() - start_time) * 1000
                
                return TerminalResult(
                    exit_code=-1,
                    stdout="",
                    stderr=f"Command timeout after {timeout}s",
                    success=False,
                    command=command,
                    duration_ms=duration_ms
                )
        
        except Exception as e:
            duration_ms = (asyncio.get_event_loop().time() - start_time) * 1000
            
            return TerminalResult(
                exit_code=-1,
                stdout="",
                stderr=f"Execution error: {str(e)}",
                success=False,
                command=command,
                duration_ms=duration_ms
            )
    
    async def stream_command(
        self,
        command: str,
        timeout: int = 30
    ):
        """
        Stream output line-by-line as it executes.
        Yields (line_type, line_content) tuples.
        """
        is_valid, error_msg = self._validate_command(command)
        if not is_valid:
            yield ("stderr", error_msg)
            yield ("exit_code", -1)
            return
        
        try:
            process = await asyncio.create_subprocess_shell(
                command,
                stdout=asyncio.subprocess.PIPE,
                stderr=asyncio.subprocess.PIPE,
                cwd=self.cwd,
                env=self.env_vars
            )
            
            async def read_stream(stream, line_type):
                while True:
                    try:
                        line = await asyncio.wait_for(stream.readline(), timeout=0.1)
                        if not line:
                            break
                        yield (line_type, line.decode('utf-8', errors='replace').rstrip())
                    except asyncio.TimeoutError:
                        continue
            
            # Read both stdout and stderr concurrently
            stdout_task = asyncio.create_task(
                self._collect_stream(process.stdout, "stdout")
            )
            stderr_task = asyncio.create_task(
                self._collect_stream(process.stderr, "stderr")
            )
            
            # Yield lines as they come
            pending = {stdout_task, stderr_task}
            while pending:
                done, pending = await asyncio.wait(
                    pending, return_when=asyncio.FIRST_COMPLETED
                )
                for task in done:
                    for line_type, line in task.result():
                        yield (line_type, line)
            
            # Wait for process to complete with timeout
            try:
                await asyncio.wait_for(process.wait(), timeout=timeout)
                yield ("exit_code", process.returncode)
            except asyncio.TimeoutError:
                process.kill()
                yield ("stderr", f"Command timeout after {timeout}s")
                yield ("exit_code", -1)
        
        except Exception as e:
            yield ("stderr", f"Execution error: {str(e)}")
            yield ("exit_code", -1)
    
    async def _collect_stream(self, stream, line_type):
        """Helper to collect stream output"""
        lines = []
        while True:
            line = await stream.readline()
            if not line:
                break
            lines.append((line_type, line.decode('utf-8', errors='replace').rstrip()))
        return lines


# Tool spec for LLM
TERMINAL_TOOL_SPEC = {
    "name": "execute_terminal",
    "description": (
        "Execute bash/shell commands with safety constraints. "
        "Use this to: run npm/yarn commands, git operations, docker commands, "
        "file operations (ls, cat, grep, find), and system utilities. "
        "Commands are validated against a whitelist for security. "
        "Examples: 'npm install', 'git status', 'docker ps', 'ls -la', 'cat file.txt'"
    ),
    "parameters": {
        "type": "object",
        "properties": {
            "command": {
                "type": "string",
                "description": "The shell command to execute. Must be a whitelisted command.",
            },
            "timeout": {
                "type": "number",
                "description": "Maximum execution time in seconds (default: 30, max: 300)",
            },
        },
        "required": ["command"],
    },
}


async def execute_terminal_handler(arguments: Dict[str, Any]) -> tuple[str, bool]:
    """Handler for terminal command execution."""
    try:
        command = arguments.get("command", "").strip()
        timeout = min(arguments.get("timeout", 30), 300)  # Max 5 minutes
        
        if not command:
            return "Error: Command is required", False
        
        logger.info(f"Executing terminal command: {command}")
        
        executor = TerminalExecutor()
        result = await executor.execute_command(command, timeout=timeout)
        
        # Format output
        output_lines = [
            f"$ {result.command}",
            "",
        ]
        
        if result.stdout:
            output_lines.append(result.stdout)
        
        if result.stderr:
            output_lines.append(f"[stderr] {result.stderr}")
        
        output_lines.append("")
        output_lines.append(f"Exit code: {result.exit_code}")
        output_lines.append(f"Duration: {result.duration_ms:.0f}ms")
        
        output = "\n".join(output_lines)
        
        if result.success:
            return f"✅ Command executed successfully\n{output}", True
        else:
            return f"❌ Command failed\n{output}", False
            
    except Exception as e:
        logger.error(f"Terminal execution error: {e}")
        return f"❌ Error executing command: {str(e)}", False