"""Command-line interface for the text analyzer."""

import argparse
import json
import sys
from pathlib import Path
from typing import Final

from text_analyzer.core import TextStatistics, analyze_file

DEFAULT_TOP: Final[int] = 10
DEFAULT_MIN_LEN: Final[int] = 1
DEFAULT_ENCODING: Final[str] = "utf-8"


def build_parser() -> argparse.ArgumentParser:
    """Build command-line parser."""
    parser = argparse.ArgumentParser(
        prog="text-analyzer",
        description="Analyze a text file.",
    )

    parser.add_argument(
        "path",
        type=Path,
        help="Path to the text file.",
    )

    parser.add_argument(
        "--top",
        type=int,
        default=DEFAULT_TOP,
        help="Number of most frequent words.",
    )

    parser.add_argument(
        "--min-len",
        type=int,
        default=DEFAULT_MIN_LEN,
        help="Minimum word length.",
    )

    parser.add_argument(
        "--format",
        choices=("text", "json"),
        default="text",
        help="Output format.",
    )

    parser.add_argument(
        "--encoding",
        default=DEFAULT_ENCODING,
        help="Input file encoding.",
    )

    return parser


def format_text(statistics: TextStatistics) -> str:
    """Format statistics as text."""
    lines = [
        f"Lines: {statistics.lines}",
        f"Words: {statistics.words}",
        f"Characters: {statistics.characters}",
        "Top words:",
    ]

    if statistics.top_words:
        for word, count in statistics.top_words:
            lines.append(f"  {word}: {count}")
    else:
        lines.append("  No words found.")

    return "\n".join(lines)


def format_json(statistics: TextStatistics) -> str:
    """Format statistics as JSON."""
    data = {
        "lines": statistics.lines,
        "words": statistics.words,
        "characters": statistics.characters,
        "top_words": [
            {
                "word": word,
                "count": count,
            }
            for word, count in statistics.top_words
        ],
    }

    return json.dumps(
        data,
        ensure_ascii=True,
        indent=2,
    )


def main() -> int:
    """Run CLI application."""
    parser = build_parser()
    args = parser.parse_args()

    if args.top < 0:
        print(
            "Error: --top must be non-negative.",
            file=sys.stderr,
        )
        return 2

    if args.min_len < 1:
        print(
            "Error: --min-len must be at least 1.",
            file=sys.stderr,
        )
        return 2

    try:
        statistics = analyze_file(
            args.path,
            top=args.top,
            min_len=args.min_len,
            encoding=args.encoding,
        )
    except FileNotFoundError:
        print(
            f"Error: file not found: {args.path}",
            file=sys.stderr,
        )
        return 1
    except UnicodeError:
        print(
            f"Error: cannot decode file using encoding: {args.encoding}",
            file=sys.stderr,
        )
        return 1
    except OSError as exc:
        print(
            f"Error: cannot read file: {exc}",
            file=sys.stderr,
        )
        return 1
    except ValueError as exc:
        print(
            f"Error: {exc}",
            file=sys.stderr,
        )
        return 2

    if args.format == "json":
        print(format_json(statistics))
    else:
        print(format_text(statistics))

    return 0


if __name__ == "__main__":
    raise SystemExit(main())