//! Lua bindings for the proactive scheduler.
//!
//! Usage:
//!   jarvis.scheduler.add({
//!       name = "Daily briefing",
//!       schedule = "daily 09:00",
//!       action = { type = "speak", text = "Доброе утро. Готов к работе." }
//!   })
//!
//!   jarvis.scheduler.add({
//!       name = "Reminder",
//!       schedule = "in 5 minutes",
//!       action = { type = "speak", text = "Выключи кофеварку." }
//!   })
//!
//!   for _, t in ipairs(jarvis.scheduler.list()) do
//!       print(t.id, t.name, t.schedule_human)
//!   end
//!
//!   jarvis.scheduler.remove(id)
//!   jarvis.scheduler.clear()
//!
//! Schedule string syntax (see `scheduler::Schedule::parse`):
//!   "daily HH:MM" | "at HH:MM" | "every N minutes" | "every N hours" | "in N minutes" | "in N hours"

use mlua::{Lua, Table, Value};

use crate::scheduler::{self, Action, Schedule, ScheduledTask};

pub fn register(lua: &Lua, jarvis: &Table) -> mlua::Result<()> {
    let sched = lua.create_table()?;

    let add_fn = lua.create_function(|_, t: Table| {
        let name: String = t.get::<Option<String>>("name")?.unwrap_or_else(|| "task".to_string());
        let schedule_str: String = t.get::<String>("schedule")?;
        let id: String = t.get::<Option<String>>("id")?.unwrap_or_default();

        let action_tbl: Table = t.get::<Table>("action")?;
        let action_type: String = action_tbl.get::<String>("type")?;
        let action = match action_type.as_str() {
            "speak" => Action::Speak {
                text: action_tbl.get::<String>("text").unwrap_or_default(),
            },
            "lua" => Action::Lua {
                script_path: action_tbl.get::<String>("script_path").unwrap_or_default(),
            },
            other => return Err(mlua::Error::external(format!("unknown action type: {}", other))),
        };

        let schedule = Schedule::parse(&schedule_str)
            .map_err(|e| mlua::Error::external(format!("bad schedule '{}': {}", schedule_str, e)))?;

        let task = ScheduledTask {
            id,
            name,
            schedule,
            action,
            last_fired: None,
            enabled: true,
            created_at: 0,
        };
        scheduler::add(task).map_err(mlua::Error::external)
    })?;
    sched.set("add", add_fn)?;

    let remove_fn = lua.create_function(|_, id: String| {
        Ok(scheduler::remove(&id))
    })?;
    sched.set("remove", remove_fn)?;

    let clear_fn = lua.create_function(|_, ()| {
        Ok(scheduler::clear())
    })?;
    sched.set("clear", clear_fn)?;

    // Remove all tasks whose name OR speak text matches `query` (substring,
    // case-insensitive). Returns count removed.
    let remove_by_text_fn = lua.create_function(|_, query: String| {
        Ok(scheduler::remove_by_text(&query))
    })?;
    sched.set("remove_by_text", remove_by_text_fn)?;

    // Find (don't remove) tasks matching query. Returns array of tasks.
    let find_by_text_fn = lua.create_function(|lua, (query, n): (String, Option<usize>)| {
        let arr = lua.create_table()?;
        for (i, t) in scheduler::find_by_text(&query, n.unwrap_or(5)).iter().enumerate() {
            arr.set(i + 1, task_to_lua(lua, t)?)?;
        }
        Ok(arr)
    })?;
    sched.set("find_by_text", find_by_text_fn)?;

    let list_fn = lua.create_function(|lua, ()| {
        let arr = lua.create_table()?;
        for (i, t) in scheduler::list().iter().enumerate() {
            arr.set(i + 1, task_to_lua(lua, t)?)?;
        }
        Ok(arr)
    })?;
    sched.set("list", list_fn)?;

    let count_fn = lua.create_function(|_, ()| {
        Ok(scheduler::list().len())
    })?;
    sched.set("count", count_fn)?;

    jarvis.set("scheduler", sched)?;
    Ok(())
}

fn task_to_lua(lua: &Lua, t: &ScheduledTask) -> mlua::Result<Table> {
    let tbl = lua.create_table()?;
    tbl.set("id", t.id.clone())?;
    tbl.set("name", t.name.clone())?;
    tbl.set("enabled", t.enabled)?;
    tbl.set("created_at", t.created_at)?;
    tbl.set("schedule_human", schedule_human(&t.schedule))?;

    let last_fired: Value = match t.last_fired {
        Some(ts) => Value::Integer(ts),
        None => Value::Nil,
    };
    tbl.set("last_fired", last_fired)?;

    let action_tbl = lua.create_table()?;
    match &t.action {
        Action::Speak { text } => {
            action_tbl.set("type", "speak")?;
            action_tbl.set("text", text.clone())?;
        }
        Action::Lua { script_path } => {
            action_tbl.set("type", "lua")?;
            action_tbl.set("script_path", script_path.clone())?;
        }
    }
    tbl.set("action", action_tbl)?;

    Ok(tbl)
}

fn schedule_human(s: &Schedule) -> String {
    match s {
        Schedule::Daily { hour, minute } => format!("каждый день в {:02}:{:02}", hour, minute),
        Schedule::Interval { seconds } => {
            if *seconds % 3600 == 0 {
                format!("каждые {} часов", seconds / 3600)
            } else if *seconds % 60 == 0 {
                format!("каждые {} минут", seconds / 60)
            } else {
                format!("каждые {} секунд", seconds)
            }
        }
        Schedule::Once { at } => {
            chrono::DateTime::from_timestamp(*at, 0)
                .map(|dt: chrono::DateTime<chrono::Utc>| {
                    dt.with_timezone(&chrono::Local).format("один раз в %H:%M %d.%m").to_string()
                })
                .unwrap_or_else(|| format!("один раз в {}", at))
        }
    }
}