from __future__ import annotations

import json
import os
import threading
import uuid
from datetime import datetime
from typing import Annotated, Dict, List, Literal, Optional

import gradio as gr

MEMORY_FILE = os.path.join(os.path.dirname(__file__), "memories.json")
_MEMORY_LOCK = threading.RLock()
_MAX_MEMORIES = 10_000


def _now_iso() -> str:
    return datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S")


def _load_memories() -> List[Dict[str, str]]:
    if not os.path.exists(MEMORY_FILE):
        return []
    try:
        with open(MEMORY_FILE, "r", encoding="utf-8") as file:
            data = json.load(file)
        if isinstance(data, list):
            cleaned: List[Dict[str, str]] = []
            for item in data:
                if isinstance(item, dict) and "id" in item and "text" in item:
                    cleaned.append(item)
            return cleaned
        return []
    except Exception:
        try:
            backup = MEMORY_FILE + ".corrupt"
            if not os.path.exists(backup):
                os.replace(MEMORY_FILE, backup)
        except Exception:
            pass
        return []


def _save_memories(memories: List[Dict[str, str]]) -> None:
    tmp_path = MEMORY_FILE + ".tmp"
    with open(tmp_path, "w", encoding="utf-8") as file:
        json.dump(memories, file, ensure_ascii=False, indent=2)
    os.replace(tmp_path, MEMORY_FILE)


def _mem_save(text: str, tags: str) -> str:
    text_clean = (text or "").strip()
    if not text_clean:
        return "Error: memory text is empty."
    with _MEMORY_LOCK:
        memories = _load_memories()
        if memories and memories[-1].get("text") == text_clean:
            return "Skipped: identical to last stored memory."
        mem_id = str(uuid.uuid4())
        entry = {
            "id": mem_id,
            "text": text_clean,
            "timestamp": _now_iso(),
            "tags": tags.strip(),
        }
        memories.append(entry)
        if len(memories) > _MAX_MEMORIES:
            overflow = len(memories) - _MAX_MEMORIES
            memories = memories[overflow:]
        _save_memories(memories)
    return f"Memory saved: {mem_id}"


def _mem_list(limit: int, include_tags: bool) -> str:
    limit = max(1, min(200, limit))
    with _MEMORY_LOCK:
        memories = _load_memories()
    if not memories:
        return "No memories stored yet."
    chosen = memories[-limit:][::-1]
    lines: List[str] = []
    for memory in chosen:
        base = f"{memory['id'][:8]} [{memory.get('timestamp','?')}] {memory.get('text','')}"
        if include_tags and memory.get("tags"):
            base += f" | tags: {memory['tags']}"
        lines.append(base)
    omitted = len(memories) - len(chosen)
    if omitted > 0:
        lines.append(f"… ({omitted} older memorie{'s' if omitted!=1 else ''} omitted; total={len(memories)})")
    return "\n".join(lines)


def _parse_search_query(query: str) -> Dict[str, List[str]]:
    import re

    result = {"tag_terms": [], "text_terms": [], "operator": "and"}
    if not query or not query.strip():
        return result
    query = re.sub(r"\s+", " ", query.strip())
    if re.search(r"\bOR\b", query, re.IGNORECASE):
        result["operator"] = "or"
        parts = re.split(r"\s+OR\s+", query, flags=re.IGNORECASE)
    else:
        parts = re.split(r"\s+(?:AND\s+)?", query, flags=re.IGNORECASE)
        parts = [p for p in parts if p.strip() and p.strip().upper() != "AND"]
    for part in parts:
        part = part.strip()
        if not part:
            continue
        tag_match = re.match(r"^tag:(.+)$", part, re.IGNORECASE)
        if tag_match:
            tag_name = tag_match.group(1).strip()
            if tag_name:
                result["tag_terms"].append(tag_name.lower())
        else:
            result["text_terms"].append(part.lower())
    return result


def _match_memory_with_query(memory: Dict[str, str], parsed_query: Dict[str, List[str]]) -> bool:
    tag_terms = parsed_query["tag_terms"]
    text_terms = parsed_query["text_terms"]
    operator = parsed_query["operator"]
    if not tag_terms and not text_terms:
        return False
    memory_text = memory.get("text", "").lower()
    memory_tags = memory.get("tags", "").lower()
    memory_tag_list = [tag.strip() for tag in memory_tags.split(",") if tag.strip()]
    tag_matches = [any(tag_term in tag for tag in memory_tag_list) for tag_term in tag_terms]
    combined_text = memory_text + " " + memory_tags
    text_matches = [text_term in combined_text for text_term in text_terms]
    all_matches = tag_matches + text_matches
    if not all_matches:
        return False
    if operator == "or":
        return any(all_matches)
    return all(all_matches)


def _mem_search(query: str, limit: int) -> str:
    q = (query or "").strip()
    if not q:
        return "Error: empty query."
    parsed_query = _parse_search_query(q)
    if not parsed_query["tag_terms"] and not parsed_query["text_terms"]:
        return "Error: no valid search terms found."
    limit = max(1, min(200, limit))
    with _MEMORY_LOCK:
        memories = _load_memories()
    matches: List[Dict[str, str]] = []
    total_matches = 0
    for memory in reversed(memories):
        if _match_memory_with_query(memory, parsed_query):
            total_matches += 1
            if len(matches) < limit:
                matches.append(memory)
    if not matches:
        return f"No matches for: {query}"
    lines = [
        f"{memory['id'][:8]} [{memory.get('timestamp','?')}] {memory.get('text','')}" + (f" | tags: {memory['tags']}" if memory.get('tags') else "")
        for memory in matches
    ]
    omitted = total_matches - len(matches)
    if omitted > 0:
        lines.append(f"… ({omitted} additional match{'es' if omitted!=1 else ''} omitted; total_matches={total_matches})")
    return "\n".join(lines)


def _mem_delete(memory_id: str) -> str:
    key = (memory_id or "").strip().lower()
    if len(key) < 4:
        return "Error: supply at least 4 characters of the id."
    with _MEMORY_LOCK:
        memories = _load_memories()
        matched = [memory for memory in memories if memory["id"].lower().startswith(key)]
        if not matched:
            return "Memory not found."
        if len(matched) > 1 and key != matched[0]["id"].lower():
            sample = ", ".join(memory["id"][:8] for memory in matched[:5])
            more = "…" if len(matched) > 5 else ""
            return f"Ambiguous prefix (matches {len(matched)} ids: {sample}{more}). Provide more characters."
        target_id = matched[0]["id"]
        memories = [memory for memory in memories if memory["id"] != target_id]
        _save_memories(memories)
    return f"Deleted memory: {target_id}"


def Memory_Manager(
    action: Annotated[Literal["save", "list", "search", "delete"], "Action to perform: save | list | search | delete"],
    text: Annotated[Optional[str], "Text content (Save only)"] = None,
    tags: Annotated[Optional[str], "Comma-separated tags (Save only)"] = None,
    query: Annotated[Optional[str], "Enhanced search with tag:name syntax, AND/OR operators (Search only)"] = None,
    limit: Annotated[int, "Max results (List/Search only)"] = 20,
    memory_id: Annotated[Optional[str], "Full UUID or unique prefix (Delete only)"] = None,
    include_tags: Annotated[bool, "Include tags (List/Search only)"] = True,
) -> str:
    act = (action or "").lower().strip()
    text = text or ""
    tags = tags or ""
    query = query or ""
    memory_id = memory_id or ""
    if act == "save":
        if not text.strip():
            return "Error: 'text' is required when action=save."
        return _mem_save(text=text, tags=tags)
    if act == "list":
        return _mem_list(limit=limit, include_tags=include_tags)
    if act == "search":
        if not query.strip():
            return "Error: 'query' is required when action=search."
        return _mem_search(query=query, limit=limit)
    if act == "delete":
        if not memory_id.strip():
            return "Error: 'memory_id' is required when action=delete."
        return _mem_delete(memory_id=memory_id)
    return "Error: invalid action (use save|list|search|delete)."


def build_interface() -> gr.Interface:
    return gr.Interface(
        fn=Memory_Manager,
        inputs=[
            gr.Dropdown(label="Action", choices=["save", "list", "search", "delete"], value="list"),
            gr.Textbox(label="Text", lines=3, placeholder="Memory text (save)"),
            gr.Textbox(label="Tags", placeholder="tag1, tag2", max_lines=1),
            gr.Textbox(label="Query", placeholder="tag:work AND tag:project OR meeting", max_lines=1),
            gr.Slider(1, 200, value=20, step=1, label="Limit"),
            gr.Textbox(label="Memory ID / Prefix", placeholder="UUID or prefix (delete)", max_lines=1),
            gr.Checkbox(value=True, label="Include Tags"),
        ],
        outputs=gr.Textbox(label="Result", lines=14),
        title="Memory Manager",
        description=(
            "<div style=\"text-align:center\">Lightweight local JSON memory store (no external DB). Choose an Action, fill only the relevant fields, and run.</div>"
        ),
        api_description=(
            "Manage short text memories with optional tags. Actions: save(text,tags), list(limit,include_tags), "
            "search(query,limit,include_tags), delete(memory_id). Enhanced search supports tag:name queries and AND/OR operators. "
            "Examples: 'tag:work', 'tag:work AND tag:project', 'meeting tag:work', 'tag:urgent OR important'. "
            "Action parameter is always required. Use Memory_Manager whenever you are given information worth remembering about the user, "
            "and search for memories when relevant."
        ),
        flagging_mode="never",
    )


__all__ = ["Memory_Manager", "build_interface", "_load_memories", "_save_memories"]