#!/usr/bin/env python3
"""Main CLI entrypoint for Multilingual NLP Entity Inherence Classifier (POC)."""

from __future__ import annotations

import argparse
import sys
from pathlib import Path

from src import __version__
from src.tools.classifier import InherenceClassifier
from src.tools.models import ClassificationError, ECPSnapshot, ErrorCode

# Ensure UTF-8 output streams across all platforms
if hasattr(sys.stdout, "reconfigure"):
    try:
        sys.stdout.reconfigure(encoding="utf-8")
    except Exception:
        pass
if hasattr(sys.stderr, "reconfigure"):
    try:
        sys.stderr.reconfigure(encoding="utf-8")
    except Exception:
        pass


def parse_args(argv: list[str] | None = None) -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        prog="classify.py",
        description="Multilingual NLP Entity Inherence Classifier (POC)",
    )
    parser.add_argument(
        "--ecp",
        type=str,
        required=True,
        help="Path to the ECP Snapshot JSON file",
    )
    parser.add_argument(
        "--content",
        type=str,
        required=True,
        help="Path to the Markdown content file",
    )
    parser.add_argument(
        "--output",
        "-o",
        type=str,
        default=None,
        help="Path to write the output JSON (default: prints to stdout)",
    )
    parser.add_argument(
        "--enable-embeddings",
        action="store_true",
        default=False,
        help="Enable optional Tier 2 vector embeddings adapter (default: false)",
    )
    parser.add_argument(
        "--enable-llm",
        action="store_true",
        default=False,
        help="Enable optional Tier 3 LLM fallback adapter (default: false)",
    )
    parser.add_argument(
        "--version",
        "-v",
        action="version",
        version=f"%(prog)s {__version__}",
    )
    return parser.parse_args(argv)


def emit_error(
    error_code: ErrorCode,
    message: str,
    details: dict | None = None,
    output_path: str | None = None,
) -> int:
    err = ClassificationError(
        error_code=error_code,
        message=message,
        details=details or {},
    )
    err_json = err.to_json_str(indent=2)

    if output_path:
        try:
            out_file = Path(output_path)
            out_file.parent.mkdir(parents=True, exist_ok=True)
            out_file.write_text(err_json, encoding="utf-8")
        except Exception:
            pass

    sys.stderr.write(err_json + "\n")
    return 1


def main(argv: list[str] | None = None) -> int:
    try:
        args = parse_args(argv)
    except SystemExit as e:
        return int(e.code) if isinstance(e.code, int) else 2

    ecp_path = Path(args.ecp)
    content_path = Path(args.content)

    # 1. Validate ECP file existence and readability
    if not ecp_path.is_file():
        return emit_error(
            ErrorCode.INVALID_ECP_JSON,
            f"ECP snapshot file not found: '{args.ecp}'",
            {"path": str(args.ecp)},
            output_path=args.output,
        )

    try:
        ecp_raw = ecp_path.read_text(encoding="utf-8")
    except Exception as e:
        return emit_error(
            ErrorCode.INVALID_ECP_JSON,
            f"Failed to read ECP file: {e}",
            {"path": str(args.ecp), "error": str(e)},
            output_path=args.output,
        )

    try:
        ecp = ECPSnapshot.from_json_str(ecp_raw)
    except ValueError as e:
        error_msg = str(e)
        if "Missing required field" in error_msg:
            return emit_error(
                ErrorCode.MISSING_REQUIRED_FIELD,
                error_msg,
                {"path": str(args.ecp)},
                output_path=args.output,
            )
        return emit_error(
            ErrorCode.INVALID_ECP_JSON,
            error_msg,
            {"path": str(args.ecp)},
            output_path=args.output,
        )

    # 2. Validate Content file existence and readability
    if not content_path.is_file():
        return emit_error(
            ErrorCode.INVALID_MARKDOWN,
            f"Content markdown file not found: '{args.content}'",
            {"path": str(args.content)},
            output_path=args.output,
        )

    try:
        content_raw = content_path.read_text(encoding="utf-8")
    except Exception as e:
        return emit_error(
            ErrorCode.INVALID_MARKDOWN,
            f"Failed to read content file: {e}",
            {"path": str(args.content), "error": str(e)},
            output_path=args.output,
        )

    if not content_raw or len(content_raw.strip()) < 5:
        return emit_error(
            ErrorCode.EMPTY_CONTENT,
            "Content file is empty or contains insufficient text (minimum 5 non-whitespace characters required)",
            {"path": str(args.content), "length": len(content_raw.strip()) if content_raw else 0},
            output_path=args.output,
        )

    # 3. Execute Classification
    classifier = InherenceClassifier(
        enable_embeddings=args.enable_embeddings,
        enable_llm=args.enable_llm,
    )

    try:
        result = classifier.classify(ecp, content_raw)
    except ValueError as e:
        return emit_error(
            ErrorCode.INVALID_MARKDOWN,
            str(e),
            {"path": str(args.content)},
            output_path=args.output,
        )
    except Exception as e:
        return emit_error(
            ErrorCode.INVALID_MARKDOWN,
            f"Classification processing error: {e}",
            {"error": str(e)},
            output_path=args.output,
        )

    result_json = result.to_json_str(indent=2)

    # 4. Output results
    if args.output:
        try:
            out_file = Path(args.output)
            out_file.parent.mkdir(parents=True, exist_ok=True)
            out_file.write_text(result_json, encoding="utf-8")
        except Exception as e:
            return emit_error(
                ErrorCode.INVALID_MARKDOWN,
                f"Failed to write output file: {e}",
                {"output_path": str(args.output), "error": str(e)},
            )
    else:
        sys.stdout.write(result_json + "\n")

    return 0


if __name__ == "__main__":
    sys.exit(main())