#!/usr/bin/env python3
"""Build source/target training pairs from andstor/defects4j_fixed."""

import argparse
import json
from collections import defaultdict
from pathlib import Path
from typing import Any, Dict, Iterable, List, Tuple

from datasets import Dataset, load_dataset


Record = Dict[str, Any]


def normalize_line_endings(text: str) -> str:
    return text.replace("\r\n", "\n").replace("\r", "\n")


def collapse_whitespace(text: str) -> str:
    return " ".join((text or "").split())


def class_declaration(class_info: Dict[str, Any]) -> str:
    class_name = class_info.get("identifier", "UnknownClass")
    superclass = (class_info.get("superclass") or "").strip()
    interfaces = collapse_whitespace(class_info.get("interfaces", ""))

    declaration = f"public class {class_name}"
    if superclass:
        declaration += f" extends {superclass}"
    if interfaces:
        declaration += f" implements {interfaces}"

    return declaration + " {"


def field_lines(class_info: Dict[str, Any]) -> List[str]:
    fields = class_info.get("fields") or []
    lines: List[str] = []
    for field in fields:
        original = (field.get("original_string") or "").strip()
        if original:
            lines.append(original)
    return lines


def method_signature(method_info: Dict[str, Any]) -> str:
    signature = (method_info.get("full_signature") or "").strip()
    if signature:
        return collapse_whitespace(signature)

    modifiers = collapse_whitespace(method_info.get("modifiers", ""))
    return_type = collapse_whitespace(method_info.get("return", ""))
    identifier = method_info.get("identifier", "unknownMethod")
    parameters = collapse_whitespace(method_info.get("parameters", "()"))

    pieces = [part for part in [modifiers, return_type, f"{identifier}{parameters}"] if part]
    return " ".join(pieces)


def class_key(record: Record) -> Tuple[str, str, str]:
    class_info = record.get("class", {})
    return (
        str(record.get("project_id", "")),
        str(record.get("bug_id", "")),
        str(class_info.get("file", class_info.get("identifier", ""))),
    )


def method_key(method_info: Dict[str, Any]) -> str:
    return method_signature(method_info)


def strip_first_signature_line(method_body: str) -> str:
    body = normalize_line_endings(method_body)
    brace_index = body.find("{")
    if brace_index == -1:
        return body.strip("\n")

    return body[brace_index + 1 :].lstrip("\n").rstrip("\n")


def indent_lines(lines: Iterable[str], spaces: int = 4) -> List[str]:
    prefix = " " * spaces
    return [f"{prefix}{line}" if line else "" for line in lines]


def with_final_class_brace(target: str) -> str:
    cleaned = target.rstrip("\n")
    if not cleaned:
        return "}"

    return f"{cleaned}\n}}"


def build_source(
    class_info: Dict[str, Any],
    constructors: Iterable[str],
    other_methods: Iterable[str],
    focal_signature: str,
) -> str:
    parts: List[str] = [class_declaration(class_info)]

    fields = field_lines(class_info)
    if fields:
        parts.append("\n".join(indent_lines(fields)))

    ctor_lines = [f"{sig};" for sig in constructors if sig]
    if ctor_lines:
        parts.append("\n".join(indent_lines(ctor_lines)))

    method_lines = [f"{sig};" for sig in other_methods if sig]
    if method_lines:
        parts.append("\n".join(indent_lines(method_lines)))

    parts.append(f"    {focal_signature} {{")
    return "\n\n".join(parts)


def build_examples(records: List[Record]) -> List[Dict[str, Any]]:
    grouped: Dict[Tuple[str, str, str], List[Record]] = defaultdict(list)
    for record in records:
        grouped[class_key(record)].append(record)

    examples: List[Dict[str, Any]] = []

    for record in records:
        method_info = record.get("method", {})
        class_info = record.get("class", {})
        body = method_info.get("body", "")
        focal_signature = method_signature(method_info)

        cls_records = grouped[class_key(record)]

        constructors = sorted(
            {
                method_signature(r.get("method", {}))
                for r in cls_records
                if r.get("method", {}).get("constructor")
            }
        )

        focal_sig_key = method_key(method_info)
        other_method_sigs = sorted(
            {
                method_signature(r.get("method", {}))
                for r in cls_records
                if not r.get("method", {}).get("constructor")
                and method_key(r.get("method", {})) != focal_sig_key
            }
        )

        source = build_source(class_info, constructors, other_method_sigs, focal_signature)
        target = with_final_class_brace(strip_first_signature_line(body))

        examples.append(
            {
                "id": record.get("id"),
                "project_id": record.get("project_id"),
                "bug_id": record.get("bug_id"),
                "class_file": class_info.get("file"),
                "method": method_info.get("identifier"),
                "source": source,
                "target": target,
            }
        )

    return examples


def main() -> None:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--split",
        default="train",
        help="Dataset split to load (default: train).",
    )
    parser.add_argument(
        "--hub-repo",
        default="defects4j_fixed_runnable",
        help="Hugging Face dataset repo to upload to.",
    )
    parser.add_argument(
        "--output",
        default=None,
        help="Optional output JSONL file path.",
    )
    parser.add_argument(
        "--max-records",
        type=int,
        default=None,
        help="Optional limit for quick smoke tests.",
    )

    args = parser.parse_args()

    ds = load_dataset("andstor/defects4j_fixed", split=args.split)
    records: List[Record] = list(ds)

    if args.max_records is not None:
        records = records[: args.max_records]

    examples = build_examples(records)

    hf_dataset = Dataset.from_list(examples)
    hf_dataset.push_to_hub(args.hub_repo)
    print(f"Uploaded {len(examples)} examples to {args.hub_repo}")

    if args.output:
        output_path = Path(args.output)
        with output_path.open("w", encoding="utf-8") as f:
            for example in examples:
                f.write(json.dumps(example, ensure_ascii=False) + "\n")
        print(f"Wrote {len(examples)} examples to {output_path}")


if __name__ == "__main__":
    main()