"""SQLite 连接与幂等初始化。

``init_db`` 建两张表：
1. ``todos`` — 业务表（demo：待办事项）
2. ``_jiangchang_tables`` / ``_jiangchang_columns`` — 宿主数据管理展示元数据

业务表字段顺序就是宿主列展示顺序（cid 顺序）。
"""
from __future__ import annotations

import sqlite3

from db.display_metadata import (
    init_display_metadata_tables,
    seed_column_metadata_batch,
    upsert_table_metadata,
)
from util.runtime_paths import get_db_path
from db.timestamp_columns import init_updated_at_trigger

ALL_BUSINESS_TABLES:tuple[str, ...] = ("todos")

# ---- 业务表 DDL（待办事项）----
# 字段顺序 = 数据管理列展示顺序；状态/优先级用 options_json 给宿主做下拉筛选
_TODOS_DDL = """
CREATE TABLE IF NOT EXISTS todos (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    title TEXT NOT NULL,
    status TEXT NOT NULL DEFAULT 'pending',
    priority TEXT NOT NULL DEFAULT 'normal',
    due_at INTEGER,
    created_at INTEGER NOT NULL DEFAULT (unixepoch()),
    updated_at INTEGER NOT NULL DEFAULT (unixepoch())
)
"""

_TODOS_INDEX = """
CREATE INDEX IF NOT EXISTS idx_todos_status ON todos(status)
"""


def get_conn() -> sqlite3.Connection:
    return sqlite3.connect(get_db_path())


def _init_business_timestamp_triggers(cursor) -> None:
    """ for table_name in ALL_BUSINESS_TABLES:
        init_updated_at_trigger(cursor, table_name) """
    init_updated_at_trigger(cursor, "todos")


def _seed_todos_display_metadata(cursor) -> None:
    """写 ``todos`` 表与字段的中文展示元数据。"""
    upsert_table_metadata(
        cursor,
        table_name="todos",
        display_name="待办事项",
        description="本技能的核心业务表：每条待办事项一行。",
        grid_help="所有的待办事项，包括待办、已办、已删除。",
        visible=1,
        readonly=1,  # 整表只读：增删改通过技能 Action 走，宿主不直写
        default_sort_json='[{"column":"created_at","direction":"desc"}]',
        default_visible_columns_json='["title","status","priority","due_at","created_at"]',
    )
    seed_column_metadata_batch(
        cursor,
        table_name="todos",
        columns=[
            {"column_name": "id", "display_name": "编号", "description": "主键",
             "visible": 1, "searchable": 1, "editable": 0, "display_type": "number"},
            {"column_name": "title", "display_name": "标题", "description": "待办事项内容",
             "grid_help": "简明描述要做的事", "visible": 1, "searchable": 1, "editable": 1,
             "display_type": "text"},
            {"column_name": "status", "display_name": "状态", "description": "pending/done",
             "grid_help": "pending=待办，done=完成", "visible": 1, "searchable": 1, "editable": 0,
             "display_type": "enum",
             "options_json": '[{"value":"pending","label":"待办"},{"value":"done","label":"完成"}]'},
            {"column_name": "priority", "display_name": "优先级", "description": "high/normal/low",
             "visible": 1, "searchable": 1, "editable": 1, "display_type": "enum",
             "options_json": '[{"value":"high","label":"高"},{"value":"normal","label":"中"},{"value":"low","label":"低"}]'},
            {"column_name": "due_at", "display_name": "截止时间", "description": "Unix 秒；可空",
             "visible": 1, "searchable": 1, "editable": 1, "display_type": "datetime_unix_seconds"},
            {"column_name": "created_at", "display_name": "创建时间", "description": "Unix 秒",
             "visible": 1, "searchable": 0, "editable": 0, "display_type": "datetime_unix_seconds"},
            {"column_name": "updated_at", "display_name": "更新时间", "description": "Unix 秒",
             "visible": 0, "searchable": 0, "editable": 0, "display_type": "datetime_unix_seconds"},
        ],
    )


def init_db() -> None:
    """幂等创建/迁移本地 SQLite 与数据管理元数据。"""
    conn = get_conn()
    try:
        cur = conn.cursor()
        # 1. 元数据表（先建，方便其它步骤 upsert）
        init_display_metadata_tables(cur)
        # 2. 业务表
        cur.execute(_TODOS_DDL)
        cur.execute(_TODOS_INDEX)
        _init_business_timestamp_triggers(cur)
        # 3. 业务表展示元数据
        _seed_todos_display_metadata(cur)

       
        conn.commit()
    finally:
        conn.close()