//! 首页卡片：只存标题/顺序，内容由 `card_group` 勾选分组组成。
//!
//! 卡片与分组是多对多：一张卡可以放不同格式的分组，分组也可以被多张卡复用。
//! 卡片本身不拥有数据，删卡不影响内容。

use rusqlite::{Connection, OptionalExtension, params};
use serde::Deserialize;
use serde_json::{Value, json};

use crate::{db::entries, db::map_error, error::StashError};

#[derive(Debug, Clone, Deserialize)]
pub struct NewCard {
    pub title: String,
}

#[derive(Debug, Clone, Default, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct UpdateCard {
    pub title: Option<String>,
    pub sort: Option<i64>,
}

#[derive(Debug, Clone, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct CardGroupInput {
    pub group_key: String,
    #[serde(default)]
    pub preview_limit: Option<i64>,
}

pub fn load(conn: &Connection) -> Result<Vec<Value>, StashError> {
    let mut stmt = conn
        .prepare("SELECT id, key, title, sort FROM card ORDER BY sort, id")
        .map_err(map_error)?;

    let cards = stmt
        .query_map([], |row| {
            Ok((
                row.get::<_, i64>(0)?,
                row.get::<_, String>(1)?,
                row.get::<_, String>(2)?,
                row.get::<_, i64>(3)?,
            ))
        })
        .map_err(map_error)?
        .collect::<Result<Vec<_>, _>>()
        .map_err(map_error)?;

    drop(stmt);

    let mut result = Vec::with_capacity(cards.len());
    for (id, key, title, sort) in cards {
        let mut group_stmt = conn
            .prepare(
                "SELECT group_key, preview_limit FROM card_group
                 WHERE card_id = ?1 ORDER BY sort",
            )
            .map_err(map_error)?;
        let groups = group_stmt
            .query_map([id], |row| {
                Ok((
                    row.get::<_, String>(0)?,
                    row.get::<_, Option<i64>>(1)?,
                ))
            })
            .map_err(map_error)?
            .collect::<Result<Vec<_>, _>>()
            .map_err(map_error)?;

        result.push(json!({
            "id": id,
            "key": key,
            "title": title,
            "sort": sort,
            "groups": groups
                .into_iter()
                .map(|(group_key, preview_limit)| json!({
                    "groupKey": group_key,
                    "previewLimit": preview_limit,
                }))
                .collect::<Vec<_>>(),
        }));
    }

    Ok(result)
}

pub fn create(conn: &mut Connection, new: NewCard) -> Result<i64, StashError> {
    let title = new.title.trim();
    if title.is_empty() || title.chars().count() > 40 {
        return Err(StashError::InvalidDirectory("卡片名称需为 1–40 个字".into()));
    }

    let tx = conn.transaction().map_err(map_error)?;
    let sort: i64 = tx
        .query_row("SELECT COALESCE(MAX(sort), 0) + 1 FROM card", [], |row| {
            row.get(0)
        })
        .map_err(map_error)?;

    tx.execute(
        "INSERT INTO card (key, title, sort) VALUES ('pending', ?1, ?2)",
        params![title, sort],
    )
    .map_err(map_error)?;
    let id = tx.last_insert_rowid();
    tx.execute(
        "UPDATE card SET key = ?1 WHERE id = ?2",
        params![format!("card-{id}"), id],
    )
    .map_err(map_error)?;

    entries::audit(&tx, "card.create", &format!("card-{id}"), title)?;
    tx.commit().map_err(map_error)?;
    Ok(id)
}

pub fn update(conn: &mut Connection, id: i64, patch: UpdateCard) -> Result<(), StashError> {
    let current: Option<(String, String, i64)> = conn
        .query_row(
            "SELECT key, title, sort FROM card WHERE id = ?1",
            [id],
            |row| Ok((row.get(0)?, row.get(1)?, row.get(2)?)),
        )
        .optional()
        .map_err(map_error)?;

    let Some((current_key, current_title, current_sort)) = current else {
        return Err(StashError::NotFound(format!("卡片不存在: {id}")));
    };
    if current_key == "local-service" && patch.title.is_some() {
        return Err(StashError::InvalidDirectory(
            "本地服务卡片由系统生成，不能改名".into(),
        ));
    }

    let title = match patch.title {
        Some(title) => {
            let title = title.trim().to_string();
            if title.is_empty() || title.chars().count() > 40 {
                return Err(StashError::InvalidDirectory("卡片名称需为 1–40 个字".into()));
            }
            title
        }
        None => current_title,
    };
    let sort = patch.sort.unwrap_or(current_sort);

    let tx = conn.transaction().map_err(map_error)?;
    tx.execute(
        "UPDATE card SET title = ?1, sort = ?2 WHERE id = ?3",
        params![title, sort, id],
    )
    .map_err(map_error)?;
    entries::audit(&tx, "card.update", &format!("card-{id}"), &title)?;
    tx.commit().map_err(map_error)?;
    Ok(())
}

pub fn remove(conn: &Connection, id: i64) -> Result<(), StashError> {
    let key: Option<String> = conn
        .query_row("SELECT key FROM card WHERE id = ?1", [id], |row| row.get(0))
        .optional()
        .map_err(map_error)?;
    if key.as_deref() == Some("local-service") {
        return Err(StashError::InvalidDirectory(
            "本地服务卡片由系统生成，不能删除".into(),
        ));
    }
    let removed = conn
        .execute("DELETE FROM card WHERE id = ?1", [id])
        .map_err(map_error)?;
    if removed == 0 {
        return Err(StashError::NotFound(format!("卡片不存在: {id}")));
    }
    entries::audit(conn, "card.delete", &format!("card-{id}"), "")?;
    Ok(())
}

/// 整组替换卡片勾选的分组（顺序即数组顺序）。
pub fn set_groups(
    conn: &mut Connection,
    id: i64,
    groups: Vec<CardGroupInput>,
) -> Result<(), StashError> {
    let key: Option<String> = conn
        .query_row("SELECT key FROM card WHERE id = ?1", [id], |row| row.get(0))
        .optional()
        .map_err(map_error)?;
    if key.as_deref() == Some("local-service") {
        return Err(StashError::InvalidDirectory(
            "本地服务卡片由系统生成，不能配置分组".into(),
        ));
    }

    let exists: i64 = conn
        .query_row("SELECT COUNT(*) FROM card WHERE id = ?1", [id], |row| row.get(0))
        .map_err(map_error)?;
    if exists == 0 {
        return Err(StashError::NotFound(format!("卡片不存在: {id}")));
    }

    for group in &groups {
        let node_exists: i64 = conn
            .query_row("SELECT COUNT(*) FROM node WHERE key = ?1", [&group.group_key], |row| {
                row.get(0)
            })
            .map_err(map_error)?;
        if node_exists == 0 {
            return Err(StashError::NotFound(format!(
                "分组不存在: {}",
                group.group_key
            )));
        }
        if let Some(limit) = group.preview_limit {
            if !(1..=60).contains(&limit) {
                return Err(StashError::InvalidDirectory("预览条数需在 1–60 之间".into()));
            }
        }
    }

    let tx = conn.transaction().map_err(map_error)?;
    tx.execute("DELETE FROM card_group WHERE card_id = ?1", [id])
        .map_err(map_error)?;
    for (sort, group) in groups.iter().enumerate() {
        tx.execute(
            "INSERT INTO card_group (card_id, group_key, sort, preview_limit)
             VALUES (?1, ?2, ?3, ?4)",
            params![id, group.group_key, sort as i64, group.preview_limit],
        )
        .map_err(map_error)?;
    }
    entries::audit(&tx, "card.groups", &format!("card-{id}"), "")?;
    tx.commit().map_err(map_error)?;
    Ok(())
}