"""Извлечение символов кода через tree-sitter (Фаза 3).

Грамматики ставятся отдельными пакетами: tree-sitter-python, tree-sitter-javascript,
tree-sitter-rust и т.д. Каждый пакет экспортирует language().
"""
from __future__ import annotations
import hashlib

# Язык -> (имя модуля, признак function/class узлов)
_LANGS = {
    "python": ("tree_sitter_python", {"function_definition", "class_definition"}),
    "javascript": ("tree_sitter_javascript", {"function_declaration", "class_declaration", "method_definition"}),
    "typescript": ("tree_sitter_javascript", {"function_declaration", "class_declaration", "method_definition"}),
    "rust": ("tree_sitter_rust", {"function_item", "struct_item", "impl_item", "trait_item", "enum_item"}),
}


def _parser(language: str):
    """Вернуть (Parser, kind_nodes) для языка."""
    from tree_sitter import Language, Parser
    spec = _LANGS.get(language)
    if spec is None:
        raise ValueError(f"unsupported language: {language}")
    mod_name, kind_nodes = spec
    mod = __import__(mod_name)
    lang = Language(mod.language())
    return Parser(lang), kind_nodes


def extract_symbols(source: str, language: str, repo: str = "", path: str = "") -> list[dict]:
    """Вернуть символы (function/class/method/type/const) из исходника.

    tree-sitter индексирует байтами UTF-8, поэтому слайсим из bytes (src),
    а не из str (source) — иначе кириллица в комментариях сбивает индексы.
    """
    parser, kind_nodes = _parser(language)
    src = source.encode("utf-8")
    tree = parser.parse(src)
    symbols: list[dict] = []

    def walk(node):
        if node.type in kind_nodes:
            name_node = node.child_by_field_name("name")
            name = src[name_node.start_byte:name_node.end_byte].decode("utf-8", "replace") if name_node else "?"
            # сигнатура: от начала узла до первого тела/блока (первые 200 байт)
            sig = src[node.start_byte:min(node.end_byte, node.start_byte + 200)].decode("utf-8", "replace")
            if "function" in node.type or node.type in ("function_item", "function_declaration", "method_definition"):
                kind = "function"
            elif "class" in node.type or node.type in ("struct_item", "impl_item", "trait_item"):
                kind = "class"
            elif "enum" in node.type:
                kind = "type"
            else:
                kind = "type"
            symbols.append({
                "repo": repo, "path": path, "language": language,
                "symbol_name": name, "kind": kind,
                "signature": sig,
                "body_hash": hashlib.sha256(src[node.start_byte:node.end_byte]).hexdigest(),
                "line_start": node.start_point[0] + 1, "line_end": node.end_point[0] + 1,
            })
        for child in node.children:
            walk(child)

    walk(tree.root_node)
    return symbols


def store_symbols(conn, source: str, language: str, repo: str = "", path: str = "",
                 sync_memgraph: bool = True) -> int:
    """Извлечь и сохранить символы кода в pm_code_symbol (+ узлы Memgraph).

    Возвращает число сохранённых.
    """
    from . import memgraph_store
    syms = extract_symbols(source, language, repo, path)
    n = 0
    with conn.cursor() as cur:
        for s in syms:
            cur.execute(
                """INSERT INTO pm_code_symbol (repo, path, language, symbol_name, kind,
                                               signature, body_hash, line_start, line_end)
                   VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s)
                   ON CONFLICT DO NOTHING""",
                (s["repo"], s["path"], s["language"], s["symbol_name"], s["kind"],
                 s["signature"], s["body_hash"], s["line_start"], s["line_end"]),
            )
            n += 1
            if sync_memgraph:
                try:
                    memgraph_store.upsert_code_symbol(
                        s["symbol_name"], repo=s["repo"], path=s["path"],
                        language=s["language"], kind=s["kind"],
                    )
                except Exception:
                    pass
    conn.commit()
    return n


def store_file(conn, path: str, repo: str = "") -> int:
    """По расширению файла определить язык и сохранить символы."""
    ext = path.rsplit(".", 1)[-1].lower() if "." in path else ""
    lang = {".py": "python", ".js": "javascript", ".ts": "typescript", ".rs": "rust"}.get("." + ext)
    if lang is None:
        return 0
    source = open(path, encoding="utf-8").read()
    return store_symbols(conn, source, lang, repo, path)