"""Unified process tool for HIP-0300 architecture.

This module provides a single unified 'exec' tool that handles all process operations:
- exec: Execute commands (the ONE execution primitive)
- ps: List processes
- kill: Kill processes
- logs: Get process logs

Following Unix philosophy: one tool for the Execution axis.
All command execution goes through proc.exec.
"""

import os
import json
import signal
import asyncio
from typing import Any, Dict, ClassVar, Optional
from pathlib import Path
from datetime import datetime

from mcp.server import FastMCP
from mcp.server.fastmcp import Context as MCPContext

from hanzo_tools.core import (
    BaseTool,
    ToolError,
    NotFoundError,
    InvalidParamsError,
)
from hanzo_tools.shell.base_process import (
    AUTO_BACKGROUND_TIMEOUT,
    ProcessManager,
    get_shell_executor,
)


class ExecTool(BaseTool):
    """Unified process execution tool (HIP-0300).

    Handles all process operations on a single axis:
    - exec: Execute commands
    - ps: List processes
    - kill: Kill processes
    - logs: Get process logs

    CRITICAL: exec is the ONE execution primitive.
    All command execution goes through proc.exec.
    """

    name: ClassVar[str] = "exec"
    VERSION: ClassVar[str] = "0.12.0"

    def __init__(self, tools: Optional[Dict[str, Any]] = None):
        super().__init__()
        self.tools = tools or {}
        self.process_manager = ProcessManager()
        self._shell = self._resolve_shell()
        self._register_proc_actions()

    def _resolve_shell(self) -> str:
        """Resolve shell - prefer zsh, fallback to bash/sh. On Windows: pwsh/cmd."""
        import sys
        import shutil

        force_shell = os.environ.get("HANZO_MCP_FORCE_SHELL")
        if force_shell:
            return force_shell

        # On Windows, prefer PowerShell/cmd
        if sys.platform == "win32":
            for shell in ("pwsh", "powershell", "cmd"):
                found = shutil.which(shell)
                if found:
                    return found
            return "cmd.exe"

        for shell in ["zsh", "bash", "fish", "dash", "sh"]:
            for prefix in ["/opt/homebrew/bin", "/usr/local/bin", "/bin", "/usr/bin"]:
                full_path = f"{prefix}/{shell}"
                if os.path.isfile(full_path) and os.access(full_path, os.X_OK):
                    return full_path
            found = shutil.which(shell)
            if found:
                return found

        return "sh"

    @property
    def description(self) -> str:
        shell_name = os.path.basename(self._shell)
        return f"""Unified process execution tool (HIP-0300).

Actions:
- exec: Execute command (shell: {shell_name})
- wait: Wait for background process to complete (Rust parity)
- ps: List processes
- kill: Kill process
- logs: Get process logs

Returns: {{proc_id, exit_code, stdout_ref, stderr_ref}}
Auto-backgrounds commands after {AUTO_BACKGROUND_TIMEOUT}s.
"""

    def _register_proc_actions(self):
        """Register all process actions."""

        @self.action("exec", "Execute command")
        async def exec_cmd(
            ctx: MCPContext,
            command: str | list[str],
            cwd: str | None = None,
            workdir: str | None = None,  # Rust parity alias
            env: dict | None = None,
            timeout: int | None = None,
            shell: str | None = None,
        ) -> dict:
            """Execute a command.

            This is the ONE execution primitive per HIP-0300.

            Args:
                command: Command to execute (string or array of strings for Rust parity)
                cwd: Working directory
                workdir: Alias for cwd (Rust parity)
                env: Environment variables
                timeout: Timeout in seconds (default: auto-background at 45s)
                shell: Shell to use (default: detected shell)

            Returns:
                proc_id, exit_code, stdout_ref, stderr_ref
            """
            if not command:
                raise InvalidParamsError("Command is required", param="command")

            # Support array format for Rust parity
            if isinstance(command, list):
                # Join array into shell command
                import shlex

                command = " ".join(shlex.quote(arg) for arg in command)

            # Support workdir alias for Rust parity
            if workdir and not cwd:
                cwd = workdir

            # Resolve shell
            shell_path = shell or self._shell

            # Build environment
            process_env = os.environ.copy()
            if env:
                process_env.update(env)

            # Get shell executor
            executor = get_shell_executor()

            try:
                # Execute with auto-background support via run_shell
                stdout_str, stderr_str, exit_code, was_bg, proc_id = (
                    await executor.run_shell(
                        command,
                        shell=shell_path,
                        cwd=cwd,
                        env=process_env,
                        timeout=float(timeout or AUTO_BACKGROUND_TIMEOUT),
                        tool_name="exec",
                    )
                )

                # Check if backgrounded
                if was_bg:
                    return {
                        "proc_id": proc_id or "unknown",
                        "exit_code": None,
                        "stdout_ref": f"proc:{proc_id}:stdout",
                        "stderr_ref": f"proc:{proc_id}:stderr",
                        "status": "running",
                        "message": f"Command backgrounded after {timeout or AUTO_BACKGROUND_TIMEOUT}s. Use exec(action='logs', proc_id='{proc_id}') to view output.",
                    }

                # Command completed
                return {
                    "proc_id": proc_id,
                    "exit_code": exit_code,
                    "stdout": stdout_str,
                    "stderr": stderr_str,
                    "status": "success" if exit_code == 0 else "failed",
                }

            except asyncio.TimeoutError:
                raise ToolError(
                    code="TIMEOUT",
                    message=f"Command timed out after {timeout}s",
                )
            except Exception as e:
                raise ToolError(
                    code="INTERNAL_ERROR",
                    message=f"Execution failed: {e}",
                )

        @self.action("wait", "Wait for background process to complete (Rust parity)")
        async def wait(
            ctx: MCPContext,
            proc_id: str,
            timeout_ms: int | None = None,
        ) -> dict:
            """Wait for a background process to complete.

            This matches the Rust wait tool schema.

            Args:
                proc_id: Process ID to wait for (call_id in Rust)
                timeout_ms: Maximum wait time in milliseconds (default: 600000, max: 3600000)

            Returns:
                Process result when complete or timeout
            """
            if not proc_id:
                raise InvalidParamsError("proc_id is required", param="proc_id")

            # Default and max timeout
            max_timeout_ms = 3600000  # 1 hour max (matches Rust)
            default_timeout_ms = 600000  # 10 minutes default
            timeout = timeout_ms or default_timeout_ms
            timeout = min(timeout, max_timeout_ms)
            timeout_sec = timeout / 1000

            # Get process info
            procs = self.process_manager.list_processes()
            if proc_id not in procs:
                raise NotFoundError(f"Process not found: {proc_id}")

            info = procs[proc_id]

            # If already completed, return immediately
            if not info.get("running", False):
                log_file = info.get("log_file")
                output = ""
                if log_file and Path(log_file).exists():
                    try:
                        from hanzo_async import read_file

                        output = await read_file(
                            log_file, encoding="utf-8", errors="replace"
                        )
                    except Exception:
                        pass

                return {
                    "proc_id": proc_id,
                    "exit_code": info.get("return_code", 0),
                    "output": output,
                    "status": "completed",
                }

            # Poll until complete or timeout
            start_time = datetime.now()
            poll_interval = 0.5  # 500ms

            while True:
                elapsed = (datetime.now() - start_time).total_seconds()
                if elapsed >= timeout_sec:
                    return {
                        "proc_id": proc_id,
                        "exit_code": None,
                        "output": "",
                        "status": "timeout",
                        "message": f"Timed out after {timeout_ms}ms",
                    }

                # Check if process completed
                procs = self.process_manager.list_processes()
                if proc_id not in procs:
                    raise NotFoundError(f"Process disappeared: {proc_id}")

                info = procs[proc_id]
                if not info.get("running", False):
                    # Process completed
                    log_file = info.get("log_file")
                    output = ""
                    if log_file and Path(log_file).exists():
                        try:
                            from hanzo_async import read_file

                            output = await read_file(
                                log_file, encoding="utf-8", errors="replace"
                            )
                        except Exception:
                            pass

                    return {
                        "proc_id": proc_id,
                        "exit_code": info.get("return_code", 0),
                        "output": output,
                        "status": "completed",
                        "duration_ms": int(elapsed * 1000),
                    }

                await asyncio.sleep(poll_interval)

        @self.action("ps", "List processes")
        async def ps(
            ctx: MCPContext,
            proc_id: str | None = None,
            filter: str | None = None,
        ) -> dict:
            """List tracked processes.

            Args:
                proc_id: Get specific process
                filter: Filter by command pattern

            Returns:
                List of processes with status
            """
            processes = []

            for pid, info in self.process_manager.list_processes().items():
                # Filter by proc_id
                if proc_id and pid != proc_id:
                    continue

                # Filter by command pattern
                cmd = info.get("cmd", "")
                if filter and filter.lower() not in cmd.lower():
                    continue

                processes.append(
                    {
                        "proc_id": pid,
                        "pid": info.get("pid"),
                        "command": cmd,
                        "running": info.get("running", False),
                        "exit_code": info.get("return_code"),
                        "started": info.get("started"),
                        "log_file": info.get("log_file"),
                    }
                )

            if proc_id and not processes:
                raise NotFoundError(f"Process not found: {proc_id}")

            return {
                "processes": processes,
                "total": len(processes),
            }

        @self.action("kill", "Kill process")
        async def kill(
            ctx: MCPContext,
            proc_id: str,
            signal: str | int = "TERM",
        ) -> dict:
            """Kill a process.

            Args:
                proc_id: Process ID to kill
                signal: Signal to send (default: TERM)

            Returns:
                Success status
            """
            if not proc_id:
                raise InvalidParamsError("proc_id is required", param="proc_id")

            # Find process
            procs = self.process_manager.list_processes()
            if proc_id not in procs:
                raise NotFoundError(f"Process not found: {proc_id}")

            info = procs[proc_id]
            pid = info.get("pid")

            if not pid:
                raise ToolError(
                    code="INTERNAL_ERROR",
                    message="Process has no PID",
                )

            # Resolve signal
            import sys as _sys

            if isinstance(signal, str):
                signal_map = {
                    "TERM": 15,
                    "KILL": 9,
                    "INT": 2,
                    "HUP": 1,
                    "QUIT": 3,
                }
                sig_num = signal_map.get(signal.upper(), 15)
            else:
                sig_num = signal

            try:
                if _sys.platform == "win32":
                    # On Windows, os.kill() only supports SIGTERM (terminate)
                    # and signal 0 (existence check). Use terminate semantics.
                    import subprocess
                    subprocess.call(
                        ["taskkill", "/F", "/PID", str(pid)],
                        stdout=subprocess.DEVNULL,
                        stderr=subprocess.DEVNULL,
                    )
                else:
                    os.kill(pid, sig_num)
                return {
                    "proc_id": proc_id,
                    "pid": pid,
                    "signal": sig_num,
                    "killed": True,
                }
            except ProcessLookupError:
                return {
                    "proc_id": proc_id,
                    "pid": pid,
                    "signal": sig_num,
                    "killed": False,
                    "message": "Process already terminated",
                }
            except PermissionError:
                raise ToolError(
                    code="PERMISSION_DENIED",
                    message=f"Cannot kill process {pid}: permission denied",
                )

        @self.action("logs", "Get process logs")
        async def logs(
            ctx: MCPContext,
            proc_id: str,
            tail: int = 100,
            since: str | None = None,
        ) -> dict:
            """Get process stdout/stderr.

            Args:
                proc_id: Process ID
                tail: Number of lines (default: 100)
                since: ISO timestamp to filter from

            Returns:
                stdout and stderr content
            """
            if not proc_id:
                raise InvalidParamsError("proc_id is required", param="proc_id")

            procs = self.process_manager.list_processes()
            if proc_id not in procs:
                raise NotFoundError(f"Process not found: {proc_id}")

            info = procs[proc_id]
            log_file = info.get("log_file")

            if not log_file or not Path(log_file).exists():
                return {
                    "proc_id": proc_id,
                    "stdout": "",
                    "stderr": "",
                    "message": "No log file available",
                }

            try:
                from hanzo_async import read_file

                content = await read_file(log_file, encoding="utf-8", errors="replace")

                # Apply tail
                lines = content.splitlines()
                if tail and len(lines) > tail:
                    lines = lines[-tail:]

                return {
                    "proc_id": proc_id,
                    "output": "\n".join(lines),
                    "running": info.get("running", False),
                    "exit_code": info.get("return_code"),
                    "total_lines": len(content.splitlines()),
                }
            except Exception as e:
                raise ToolError(
                    code="INTERNAL_ERROR",
                    message=f"Failed to read logs: {e}",
                )

# Backward compatibility
exec_tool = ExecTool