// showcase.mko — struct, database, errors, ownership, arenas, concurrency
// Run: mako run examples/showcase.mko

#[derive(json)]
struct Task {
    id: int
    title: string
    done: int
}

fn create_table(db: SqlDB) -> Result[int, string] {
    let rc = sql_exec_plain(db, "CREATE TABLE IF NOT EXISTS tasks (id INTEGER PRIMARY KEY, title TEXT, done INTEGER)")
    if rc != 0 {
        return error("create table failed")
    }
    Ok(0)
}

fn insert_task(db: SqlDB, title: string) -> Result[int, string] {
    let rc = sql_exec_str4(db, "INSERT INTO tasks (title, done) VALUES ($1, $2)", title, "0", "", "")
    if rc != 0 {
        return error("insert failed")
    }
    Ok(0)
}

fn get_task(db: SqlDB, title: string) -> string {
    let row = sql_query_str(db, "SELECT title FROM tasks WHERE title = $1", title)
    return row
}

fn worker(ch: chan[int], id: int, results: CMap) -> int {
    arena a {
        let label = arena_text(a, format_int(id))
        while true {
            let task_id = ch.recv()
            if task_id == 0 { break }
            let msg = "worker " + label + " processed task " + format_int(task_id)
            cmap_set(results, format_int(task_id), msg)
        }
    }
    return id
}

fn main() {
    // database setup
    let db = sql_open_sqlite("/tmp/mako_showcase.db")
    let _ = create_table(db)

    // insert some tasks
    let titles = ["build parser", "write tests", "deploy service", "fix bug", "review PR"]
    for i in 5 {
        let r = insert_task(db, titles[i])
        match r {
            Ok(_) => {}
            Err(e) => print("insert error: " + e)
        }
    }

    // query back
    let found = get_task(db, "write tests")
    if str_eq(found, "") {
        print("error: task not found")
    } else {
        print("found: " + found)
    }

    // concurrent workers with shared results
    let results = cmap_new()
    let ch = chan_new(10)

    crew t {
        let w1 = t.kick(worker(ch, 1, results))
        let w2 = t.kick(worker(ch, 2, results))
        let w3 = t.kick(worker(ch, 3, results))

        for i in 5 {
            let _ = ch.send(i + 1)
        }
        let _ = ch.send(0)
        let _ = ch.send(0)
        let _ = ch.send(0)

        let _ = w1.join()
        let _ = w2.join()
        let _ = w3.join()
    }

    // print results
    for i in 5 {
        print(cmap_get(results, format_int(i + 1)))
    }

    let _ = sql_close(db)
    let _ = remove_file("/tmp/mako_showcase.db")
    print("done")
}