"""
===============================================================================
FILE: services/prompts/diff_engine.py
PROJECT: SCUD Orion AI (Unified Architecture)
MODULE: services / prompts
ROLE: Формирование превью изменений промпта и генерация визуального HTML-Diff.

AI-CONTEXT-ANCHORS:
  - ANCHOR[PROMPT_DIFF_BUILDER]: Генерация черновика и HTML-разметки изменений.
===============================================================================
"""

from typing import Tuple, Dict, List, Set
from core.connection import get_connection

def build_prompt_diff(
    action: str, 
    section_id: int = None, 
    item_id: int = None, 
    content: str = "", 
    delete_nodes: List[Tuple[int, int]] = None,
    prompt_name: str = "main_agent"
) -> Tuple[str, str]:
    act = (action or "ADD").upper()
    nodes_to_delete: Set[Tuple[int, int]] = set()

    if delete_nodes:
        nodes_to_delete.update(delete_nodes)
    elif act == "DELETE" and section_id is not None and item_id is not None:
        nodes_to_delete.add((section_id, item_id))

    with get_connection(row_factory=True) as conn:
        cursor = conn.cursor()
        cursor.execute("""
            SELECT section_id, item_id, content 
            FROM system_prompt_nodes 
            WHERE prompt_name = ? AND is_active = 1 
            ORDER BY section_id, item_id
        """, (prompt_name,))
        existing_nodes = cursor.fetchall()

    nodes_dict = {(r["section_id"], r["item_id"]): r["content"] for r in existing_nodes}
    nodes_dict_for_draft = {k: v for k, v in nodes_dict.items() if k not in nodes_to_delete}
    
    if act not in ["DELETE", "BATCH_DELETE"] and section_id is not None and item_id is not None:
        nodes_dict_for_draft[(section_id, item_id)] = content

    draft_lines = []
    curr_sec = None
    for (s_id, i_id), txt in sorted(nodes_dict_for_draft.items()):
        if i_id == 0:
            if curr_sec is not None: draft_lines.append("")
            draft_lines.append(f"{s_id}. {txt}")
            curr_sec = s_id
        else:
            draft_lines.append(f"   {s_id}.{i_id}. {txt}")
    merged_prompt = "\n".join(draft_lines)

    diff_lines = []
    curr_sec = None
    display_nodes = dict(nodes_dict)
    if act not in ["DELETE", "BATCH_DELETE"] and section_id is not None and item_id is not None:
        display_nodes[(section_id, item_id)] = content

    for (s_id, i_id), txt in sorted(display_nodes.items()):
        if i_id == 0:
            if curr_sec is not None: diff_lines.append("")
            diff_lines.append(f"{s_id}. {txt}")
            curr_sec = s_id
        else:
            if (s_id, i_id) in nodes_to_delete:
                line_str = f'   <span class="line-through text-rose-600 font-bold bg-rose-50 px-1.5 py-0.5 rounded border border-rose-300 opacity-80">{s_id}.{i_id}. {txt} [УДАЛЕНИЕ]</span>'
            elif act == "ADD" and s_id == section_id and i_id == item_id:
                line_str = f'   <span class="text-rose-600 font-bold bg-rose-50 px-1.5 py-0.5 rounded border border-rose-300">{s_id}.{i_id}. {txt}</span>'
            else:
                line_str = f"   {s_id}.{i_id}. {txt}"
            diff_lines.append(line_str)

    return merged_prompt, "\n".join(diff_lines)