argv-todo 0.1.0

use anyhow::{Context, Result};
use rusqlite::{OptionalExtension, params};
use std::collections::BTreeMap;

use super::{Database, Todo};

impl Database {
    /// Give the selected task and every descendant the same completion state.
    pub(crate) fn toggle(&mut self, id: i64) -> Result<usize> {
        let transaction = self.connection.transaction()?;
        let done = transaction
            .query_row("SELECT done FROM todos WHERE id = ?1", [id], |row| {
                row.get::<_, bool>(0)
            })
            .optional()?
            .context("Task no longer exists; press Ctrl-r to refresh")?;
        let changed = transaction.execute(
            "WITH RECURSIVE subtree(id) AS (
                 SELECT id FROM todos WHERE id = ?1
                 UNION
                 SELECT todos.id FROM todos JOIN subtree ON todos.parent_id = subtree.id
             )
             UPDATE todos SET done = ?2, updated_at = strftime('%Y-%m-%d %H:%M:%S', 'now')
             WHERE id IN (SELECT id FROM subtree)",
            params![id, !done],
        )?;
        transaction.commit()?;
        Ok(changed)
    }

    /// Snapshot and delete whole subtrees atomically, including any newer children.
    pub(crate) fn delete(&mut self, todos: &[Todo]) -> Result<Vec<Todo>> {
        let transaction = self.connection.transaction()?;
        let mut deleted = BTreeMap::new();
        {
            let mut statement = transaction.prepare(
                "WITH RECURSIVE subtree(id) AS (
                     SELECT id FROM todos WHERE id = ?1
                     UNION
                     SELECT todos.id FROM todos JOIN subtree ON todos.parent_id = subtree.id
                 )
                 SELECT id, title, done, created_at, updated_at, parent_id, priority, position
                 FROM todos WHERE id IN (SELECT id FROM subtree) ORDER BY id",
            )?;
            for todo in todos {
                for row in statement.query_map([todo.id], Self::todo_from_row)? {
                    let row = row?;
                    deleted.insert(row.id, row);
                }
            }
        }
        for todo in todos {
            transaction.execute("DELETE FROM todos WHERE id = ?1", [todo.id])?;
        }
        transaction.commit()?;
        Ok(deleted.into_values().collect())
    }

    pub(crate) fn restore(&mut self, todos: &[Todo]) -> Result<()> {
        let transaction = self.connection.transaction()?;
        for todo in todos {
            transaction.execute(
                "INSERT INTO todos (id, title, done, created_at, updated_at, parent_id, priority, position) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)",
                params![todo.id, todo.title, todo.done, todo.created_at, todo.updated_at, todo.parent_id, todo.priority, todo.position]
            )?;
        }
        transaction.commit()?;
        Ok(())
    }
}