from __future__ import annotations

import json
from pathlib import Path
from typing import Dict, Iterator, List, Optional

RESUME_EXTS = {".pdf", ".docx", ".doc", ".txt", ".html", ".htm"}

def find_result_json(root: Path) -> List[Path]:
    return list(root.rglob("result.json"))

def _text_field_to_str(text_field) -> str:
    if isinstance(text_field, str):
        return text_field
    if isinstance(text_field, list):
        parts = []
        for item in text_field:
            if isinstance(item, str):
                parts.append(item)
            elif isinstance(item, dict) and "text" in item:
                parts.append(str(item["text"]))
        return "".join(parts)
    return ""

def iter_artifacts(result_json: Path) -> Iterator[Dict]:
    data = json.loads(result_json.read_text(encoding="utf-8", errors="ignore"))

    chats = []
    if isinstance(data, dict):
        chats = data.get("chats", {}).get("list", []) or data.get("chats", []) or []
    for chat in chats:
        chat_title = chat.get("name") or chat.get("title") or "unknown_chat"
        messages = chat.get("messages", []) or []
        for msg in messages:
            msg_id = str(msg.get("id") or "")
            msg_date = msg.get("date") or msg.get("date_unixtime") or None
            text = _text_field_to_str(msg.get("text", ""))

            file_rel = msg.get("file") or None
            file_path = None
            original_name = None
            if file_rel:
                p = (result_json.parent / file_rel).resolve()
                if p.exists() and p.suffix.lower() in RESUME_EXTS:
                    file_path = str(p)
                    original_name = p.name

            if file_path:
                yield {
                    "origin_type": "telegram_json",
                    "export_path": str(result_json.parent),
                    "chat_title": chat_title,
                    "message_id": msg_id,
                    "message_date": str(msg_date) if msg_date is not None else None,
                    "message_text": text or "",
                    "file_path": file_path,
                    "original_name": original_name,
                    "extra": {"json_path": str(result_json)},
                }
            else:
                # message-only resume paste (heuristic)
                if text and len(text.strip()) >= 500:
                    yield {
                        "origin_type": "message_text",
                        "export_path": str(result_json.parent),
                        "chat_title": chat_title,
                        "message_id": msg_id,
                        "message_date": str(msg_date) if msg_date is not None else None,
                        "message_text": text,
                        "file_path": None,
                        "original_name": None,
                        "extra": {"json_path": str(result_json)},
                    }