"""
Terminal Execution Engine — Real Command Runner
Streaming logs, timeout control, session management, self-repair loop
"""

import asyncio
import os
import pty
import select
import signal
import time
import uuid
from typing import AsyncGenerator, Callable, Dict, List, Optional

import structlog

log = structlog.get_logger()

WORKSPACE = os.environ.get("WORKSPACE_DIR", "/tmp/god_workspace")

BLOCKED_COMMANDS = [
    "rm -rf /",
    ":(){ :|:& };:",
    "mkfs",
    "shutdown",
    "reboot",
    "halt",
    "dd if=/dev/zero",
    "dd if=/dev/urandom of=/dev",
    "> /dev/sda",
    "chmod 777 /",
    "chown root /",
]


def _is_blocked(cmd: str) -> bool:
    c = cmd.strip()
    for b in BLOCKED_COMMANDS:
        if b in c:
            return True
    return False


class ProcessSession:
    """Manages a persistent shell session."""
    def __init__(self, session_id: str, cwd: str = WORKSPACE):
        self.session_id = session_id
        self.cwd = cwd
        self.history: List[Dict] = []
        self.env = os.environ.copy()
        self.env["TERM"] = "xterm-256color"
        self.env["PYTHONUNBUFFERED"] = "1"
        self.created_at = time.time()
        self.last_used = time.time()

    def record(self, cmd: str, output: str, exit_code: int, duration: float):
        self.history.append({
            "cmd": cmd,
            "output": output[:2000],
            "exit_code": exit_code,
            "duration": round(duration, 3),
            "timestamp": time.time(),
        })
        self.last_used = time.time()
        if len(self.history) > 100:
            self.history = self.history[-100:]


class TerminalEngine:
    """
    Real Terminal Execution Engine
    - Async subprocess with streaming output
    - Session management (persistent cwd + env)
    - Timeout + kill control
    - Self-repair loop (run → error → analyze → patch → retry)
    """

    def __init__(self, ws_manager=None):
        self.ws = ws_manager
        self._sessions: Dict[str, ProcessSession] = {}
        self._running_procs: Dict[str, asyncio.subprocess.Process] = {}

    # ─── Session Management ───────────────────────────────────────────────────

    def get_or_create_session(self, session_id: str, cwd: str = WORKSPACE) -> ProcessSession:
        if session_id not in self._sessions:
            self._sessions[session_id] = ProcessSession(session_id, cwd)
            os.makedirs(cwd, exist_ok=True)
        return self._sessions[session_id]

    def get_session_history(self, session_id: str) -> List[Dict]:
        sess = self._sessions.get(session_id)
        return sess.history if sess else []

    def cleanup_old_sessions(self, max_age: int = 3600):
        now = time.time()
        to_remove = [sid for sid, s in self._sessions.items() if now - s.last_used > max_age]
        for sid in to_remove:
            del self._sessions[sid]

    # ─── Execute Command ──────────────────────────────────────────────────────

    async def execute(
        self,
        command: str,
        session_id: str = "",
        task_id: str = "",
        cwd: str = "",
        timeout: int = 120,
        stream_callback: Optional[Callable] = None,
        env_override: Optional[Dict] = None,
    ) -> Dict:
        """
        Execute a shell command with real streaming output.
        Returns: {success, output, exit_code, duration, command}
        """
        if _is_blocked(command):
            result = {
                "success": False,
                "output": f"❌ BLOCKED: Dangerous command detected: {command[:60]}",
                "exit_code": -1,
                "command": command,
                "duration": 0.0,
            }
            await self._emit(task_id, session_id, "terminal_blocked", result)
            return result

        sess = self.get_or_create_session(session_id or "default", cwd or WORKSPACE)
        work_dir = cwd or sess.cwd
        os.makedirs(work_dir, exist_ok=True)

        env = sess.env.copy()
        if env_override:
            env.update(env_override)

        await self._emit(task_id, session_id, "terminal_exec", {
            "command": command[:300],
            "cwd": work_dir,
            "session_id": session_id,
        })

        start = time.time()
        output_lines = []

        try:
            proc = await asyncio.create_subprocess_shell(
                command,
                stdout=asyncio.subprocess.PIPE,
                stderr=asyncio.subprocess.STDOUT,
                cwd=work_dir,
                env=env,
            )

            if session_id:
                self._running_procs[session_id] = proc

            # Stream output line by line
            async def read_output():
                while True:
                    try:
                        line = await asyncio.wait_for(proc.stdout.readline(), timeout=5.0)
                        if not line:
                            break
                        decoded = line.decode("utf-8", errors="replace").rstrip()
                        output_lines.append(decoded)

                        # Stream via WebSocket
                        await self._emit(task_id, session_id, "terminal_output", {
                            "line": decoded,
                            "command": command[:80],
                        })

                        if stream_callback:
                            await stream_callback(decoded)

                        if len(output_lines) > 500:
                            output_lines.append("... [output truncated at 500 lines]")
                            proc.kill()
                            break
                    except asyncio.TimeoutError:
                        if proc.returncode is not None:
                            break
                        continue

            await asyncio.wait_for(
                asyncio.gather(read_output(), proc.wait()),
                timeout=timeout,
            )

        except asyncio.TimeoutError:
            try:
                proc.kill()
            except Exception:
                pass
            output_lines.append(f"\n⚠️ Command timed out after {timeout}s")
            exit_code = -1
        except Exception as e:
            output_lines.append(f"\n❌ Execution error: {str(e)}")
            exit_code = -1
        else:
            exit_code = proc.returncode or 0

        finally:
            if session_id in self._running_procs:
                del self._running_procs[session_id]

        duration = time.time() - start
        full_output = "\n".join(output_lines)

        if session_id:
            sess.record(command, full_output, exit_code, duration)

        result = {
            "success": exit_code == 0,
            "output": full_output,
            "exit_code": exit_code,
            "command": command,
            "duration": round(duration, 3),
            "cwd": work_dir,
        }

        await self._emit(task_id, session_id, "terminal_result", {
            "command": command[:100],
            "exit_code": exit_code,
            "success": exit_code == 0,
            "duration_ms": round(duration * 1000),
            "output_lines": len(output_lines),
        })

        return result

    # ─── Kill Running Process ─────────────────────────────────────────────────

    async def kill(self, session_id: str) -> Dict:
        proc = self._running_procs.get(session_id)
        if proc:
            try:
                proc.kill()
                del self._running_procs[session_id]
                return {"success": True, "action": "killed", "session_id": session_id}
            except Exception as e:
                return {"success": False, "error": str(e)}
        return {"success": False, "error": "No running process for session"}

    # ─── Execute Multiple Commands in Sequence ────────────────────────────────

    async def execute_chain(
        self,
        commands: List[str],
        session_id: str = "",
        task_id: str = "",
        cwd: str = "",
        stop_on_error: bool = True,
    ) -> Dict:
        """Run a chain of commands, passing cwd between them."""
        results = []
        current_cwd = cwd or WORKSPACE

        for i, cmd in enumerate(commands):
            # Handle 'cd' specially to persist directory
            if cmd.strip().startswith("cd "):
                new_dir = cmd.strip()[3:].strip().strip('"').strip("'")
                if not os.path.isabs(new_dir):
                    new_dir = os.path.join(current_cwd, new_dir)
                if os.path.isdir(new_dir):
                    current_cwd = new_dir
                    results.append({"command": cmd, "success": True, "output": f"Changed to {current_cwd}", "exit_code": 0})
                else:
                    results.append({"command": cmd, "success": False, "output": f"Directory not found: {new_dir}", "exit_code": 1})
                    if stop_on_error:
                        break
                continue

            result = await self.execute(
                cmd,
                session_id=session_id,
                task_id=task_id,
                cwd=current_cwd,
            )
            results.append(result)

            if not result["success"] and stop_on_error:
                break

        success = all(r.get("success", False) for r in results)
        combined_output = "\n".join(f"$ {r['command']}\n{r['output']}" for r in results)

        return {
            "success": success,
            "commands": len(commands),
            "results": results,
            "combined_output": combined_output[:5000],
            "final_cwd": current_cwd,
        }

    # ─── Self-Repair Loop ─────────────────────────────────────────────────────

    async def self_repair(
        self,
        command: str,
        error_output: str,
        ai_router=None,
        session_id: str = "",
        task_id: str = "",
        max_attempts: int = 3,
    ) -> Dict:
        """
        Real self-repair loop:
        Run → Error → Analyze → AI suggests fix → Retry
        """
        await self._emit(task_id, session_id, "self_repair_start", {
            "command": command[:100],
            "error": error_output[:200],
        })

        for attempt in range(1, max_attempts + 1):
            await self._emit(task_id, session_id, "self_repair_attempt", {
                "attempt": attempt,
                "max": max_attempts,
            })

            if ai_router:
                fix_prompt = [
                    {"role": "system", "content": "You are an expert DevOps engineer. Analyze the error and provide the EXACT fixed command or commands. Return ONLY the command(s), one per line. No explanations."},
                    {"role": "user", "content": f"Original command: {command}\n\nError output:\n{error_output[:1000]}\n\nProvide the corrected command(s):"},
                ]
                try:
                    fixed_cmd = await ai_router.complete(fix_prompt, temperature=0.1, max_tokens=300)
                    fixed_cmd = fixed_cmd.strip().strip("`").strip()
                    # Remove markdown code blocks
                    if fixed_cmd.startswith("```"):
                        lines = fixed_cmd.split("\n")
                        fixed_cmd = "\n".join(lines[1:-1]) if len(lines) > 2 else fixed_cmd
                except Exception:
                    fixed_cmd = command

                await self._emit(task_id, session_id, "self_repair_fix", {
                    "attempt": attempt,
                    "fixed_command": fixed_cmd[:200],
                })

                result = await self.execute(fixed_cmd, session_id=session_id, task_id=task_id)
                if result["success"]:
                    await self._emit(task_id, session_id, "self_repair_success", {
                        "attempt": attempt,
                        "fixed_command": fixed_cmd[:100],
                    })
                    return {
                        "success": True,
                        "fixed_command": fixed_cmd,
                        "result": result,
                        "attempts": attempt,
                    }
                error_output = result["output"]
            else:
                break

        await self._emit(task_id, session_id, "self_repair_failed", {
            "max_attempts": max_attempts,
            "last_error": error_output[:200],
        })
        return {
            "success": False,
            "error": "Self-repair exhausted all attempts",
            "last_error": error_output,
            "attempts": max_attempts,
        }

    # ─── Emit Helper ─────────────────────────────────────────────────────────

    async def _emit(self, task_id: str, session_id: str, event: str, data: Dict):
        if not self.ws:
            return
        try:
            if task_id:
                await self.ws.emit(task_id, event, data, session_id=session_id)
            if session_id:
                await self.ws.emit_chat(session_id, event, data)
        except Exception:
            pass