"""File inspection executor for reading portions of text files."""

import time
from typing import Any

from app.config import get_settings
from app.executors.base import BaseExecutor, ExecutionResult
from app.utils.validation import ValidationError, validate_file_path


class FileInspectExecutor(BaseExecutor):
    """Read portions of files for inspection.

    Security measures:
    - Path validation against allowed file root (/opt/letsbe)
    - Directory traversal prevention
    - File must exist (no blind path probing)
    - Read-only operation (no file modification)
    - Byte limit enforced (max 1MB)

    Payload:
        {
            "path": "/opt/letsbe/env/chatwoot.env",
            "max_bytes": 4096  # optional, default 4096, max 1MB
        }

    Result (success):
        {
            "path": "/opt/letsbe/env/chatwoot.env",
            "bytes_read": 123,
            "truncated": false,
            "content": "..."
        }
    """

    # Default and maximum byte limits
    DEFAULT_MAX_BYTES = 4096
    ABSOLUTE_MAX_BYTES = 1_048_576  # 1 MB

    @property
    def task_type(self) -> str:
        return "FILE_INSPECT"

    async def execute(self, payload: dict[str, Any]) -> ExecutionResult:
        """Read file content up to max_bytes.

        Args:
            payload: Must contain "path", optionally "max_bytes"

        Returns:
            ExecutionResult with file content and metadata
        """
        # Path is always required
        if "path" not in payload:
            raise ValueError("Missing required field: path")

        settings = get_settings()

        raw_path = payload["path"]
        max_bytes = payload.get("max_bytes", self.DEFAULT_MAX_BYTES)

        # Validate max_bytes is a valid integer
        try:
            max_bytes_int = int(max_bytes)
        except (TypeError, ValueError):
            return ExecutionResult(
                success=False,
                data={},
                error=f"Invalid max_bytes value: {max_bytes!r}",
            )

        # Validate max_bytes is within allowed range
        if max_bytes_int <= 0 or max_bytes_int > self.ABSOLUTE_MAX_BYTES:
            return ExecutionResult(
                success=False,
                data={},
                error=f"max_bytes must be between 1 and {self.ABSOLUTE_MAX_BYTES}",
            )

        # Validate path is under allowed file root
        try:
            validated_path = validate_file_path(
                raw_path,
                settings.allowed_file_root,
                must_exist=True,
            )
        except ValidationError as e:
            self.logger.warning("file_path_validation_failed", path=raw_path, error=str(e))
            return ExecutionResult(
                success=False,
                data={},
                error=f"Path validation failed: {e}",
            )

        self.logger.info(
            "file_inspecting",
            path=str(validated_path),
            max_bytes=max_bytes_int,
        )

        start_time = time.time()

        try:
            # Read up to max_bytes + 1 to detect truncation
            with validated_path.open("rb") as f:
                content_bytes = f.read(max_bytes_int + 1)

            truncated = len(content_bytes) > max_bytes_int
            if truncated:
                content_bytes = content_bytes[:max_bytes_int]

            # Decode as UTF-8 with errors replaced
            content_text = content_bytes.decode("utf-8", errors="replace")

            duration_ms = (time.time() - start_time) * 1000

            self.logger.info(
                "file_inspected",
                path=str(validated_path),
                bytes_read=len(content_bytes),
                truncated=truncated,
                duration_ms=duration_ms,
            )

            return ExecutionResult(
                success=True,
                data={
                    "path": str(validated_path),
                    "bytes_read": len(content_bytes),
                    "truncated": truncated,
                    "content": content_text,
                },
                duration_ms=duration_ms,
            )

        except OSError as e:
            duration_ms = (time.time() - start_time) * 1000
            self.logger.error("file_inspect_read_error", path=str(validated_path), error=str(e))
            return ExecutionResult(
                success=False,
                data={},
                error=f"Failed to read file: {e}",
                duration_ms=duration_ms,
            )
        except Exception as e:
            duration_ms = (time.time() - start_time) * 1000
            self.logger.error("file_inspect_error", path=str(validated_path), error=str(e))
            return ExecutionResult(
                success=False,
                data={},
                error=str(e),
                duration_ms=duration_ms,
            )