//! ClassicAPI's `State` namespace: bare globals, no `C_*` table. 1.12's own Lua has no path to
//! any of the posture facts here — no mounted/swim/indoor/falling getter exists on the reference
//! client at all — so these are fed from the engine through [`SelfMovement`]
//! (`script/self_movement.rs`, filled once per tick by `benilla-app`'s
//! `ui_unit::feed_self_movement`), not read off a descriptor field some stock verb already
//! exposes.
//!
//! Not built, each for a stated reason rather than a guess (`docs/ADDON_COMPAT.md` carries the
//! same list):
//! - `IsStealthed`, `GetSheathState`, `IsAssistingRitual`: no engine state tracks any of the three
//!   today; each needs its own new feed, not a binding.
//! - `GetMirrorTimerInfo`, `GetMirrorTimerProgress`: benilla's mirror timers (breath, fatigue) are
//!   event-driven only — `benilla-app`'s `ui_mirror.rs` fires `MIRROR_TIMER_START`/`_PAUSE`/`_STOP`
//!   and keeps no queryable snapshot, which these two getters would need.
//! - `Dismount`, `CancelShapeshiftForm`: actions, not getters. Vanilla cancels a form by re-casting
//!   its own spell, so an honest `CancelShapeshiftForm` needs the active form's spell id (the
//!   engine knows the form *index*, [`SelfMovement::shapeshift_form`], not the spell behind it);
//!   `Dismount` has no stock verb here to reuse at all.

use mlua::Lua;

use crate::script::binding_abi::flag;
use crate::script::Model;

/// Read one posture bool out of the per-tick snapshot, as the number 1 or nil — the shape every
/// 1.12 predicate uses, which an addon tests with `== 1` or `== nil`, never `== true`.
fn posture(lua: &Lua, f: impl FnOnce(&crate::script::SelfMovement) -> bool) -> mlua::Value {
    let model = lua.app_data_ref::<Model>().expect("model app_data");
    flag(f(&model.self_movement))
}

pub(super) fn install(lua: &Lua) -> mlua::Result<()> {
    let g = lua.globals();

    g.set(
        "IsSwimming",
        lua.create_function(|lua, ()| Ok(posture(lua, |m| m.swimming)))?,
    )?;
    g.set(
        "IsMounted",
        lua.create_function(|lua, ()| Ok(posture(lua, |m| m.mounted)))?,
    )?;
    g.set(
        "IsIndoors",
        lua.create_function(|lua, ()| Ok(posture(lua, |m| m.indoors)))?,
    )?;
    // The exact complement of `IsIndoors`: the area pass's bit is one or the other, never neither.
    g.set(
        "IsOutdoors",
        lua.create_function(|lua, ()| Ok(posture(lua, |m| !m.indoors)))?,
    )?;
    g.set(
        "IsFalling",
        lua.create_function(|lua, ()| Ok(posture(lua, |m| m.falling)))?,
    )?;

    // `GetShapeshiftFormID()`: the form index, nil when not shapeshifted — the modern spelling of
    // a fact 1.12 only exposes per-form through `GetShapeshiftForm*`.
    g.set(
        "GetShapeshiftFormID",
        lua.create_function(|lua, ()| {
            let model = lua.app_data_ref::<Model>().expect("model app_data");
            let form = model.self_movement.shapeshift_form;
            Ok((form != 0).then_some(i64::from(form)))
        })?,
    )?;

    // `IsInGroup`/`IsInRaid` read the party/raid roster directly, the one authority the stock
    // `GetNumPartyMembers`/`GetNumRaidMembers` (`script/party.rs`) already answer from — not the
    // posture snapshot, so there is only ever one source of truth for group membership.
    g.set(
        "IsInGroup",
        lua.create_function(|lua, ()| {
            let model = lua.app_data_ref::<Model>().expect("model app_data");
            Ok(flag(
                !model.party.members.is_empty() || !model.party.raid.is_empty(),
            ))
        })?,
    )?;
    g.set(
        "IsInRaid",
        lua.create_function(|lua, ()| {
            let model = lua.app_data_ref::<Model>().expect("model app_data");
            Ok(flag(!model.party.raid.is_empty()))
        })?,
    )?;

    Ok(())
}

#[cfg(test)]
mod tests {
    use crate::script::{SelfMovement, UiScript};

    #[test]
    fn posture_getters_read_the_fed_snapshot_as_one_or_nil() {
        let mut s = UiScript::new().unwrap();

        // The pre-feed default: everything false, so every getter is nil, never 0.
        assert_eq!(
            s.eval::<Option<i64>>("return IsSwimming()").unwrap(),
            None,
            "nil, not 0 — the 1.12 predicate shape an addon tests with `== nil`"
        );
        assert_eq!(s.eval::<i64>("return IsOutdoors()").unwrap(), 1);

        s.set_self_movement(SelfMovement {
            mouselooking: false,
            swimming: true,
            mounted: true,
            indoors: true,
            falling: false,
            shapeshift_form: 3,
        });

        assert_eq!(s.eval::<i64>("return IsSwimming()").unwrap(), 1);
        assert_eq!(s.eval::<i64>("return IsMounted()").unwrap(), 1);
        assert_eq!(s.eval::<i64>("return IsIndoors()").unwrap(), 1);
        assert_eq!(
            s.eval::<Option<i64>>("return IsOutdoors()").unwrap(),
            None,
            "the exact complement of IsIndoors"
        );
        assert_eq!(s.eval::<Option<i64>>("return IsFalling()").unwrap(), None);
        assert_eq!(s.eval::<i64>("return GetShapeshiftFormID()").unwrap(), 3);

        // The addon idiom holds: under a Lua boolean neither of these would be true.
        assert!(s.eval::<bool>("return IsSwimming() == 1").unwrap());
        assert!(!s.eval::<bool>("return IsSwimming() == true").unwrap());
    }

    #[test]
    fn shapeshift_form_zero_reads_nil_not_zero() {
        let mut s = UiScript::new().unwrap();
        s.set_self_movement(SelfMovement {
            shapeshift_form: 0,
            ..Default::default()
        });
        assert_eq!(
            s.eval::<Option<i64>>("return GetShapeshiftFormID()")
                .unwrap(),
            None,
            "not shapeshifted is nil, which is what a caller branches on"
        );
    }

    #[test]
    fn group_predicates_read_the_roster_not_the_posture_snapshot() {
        use crate::script::{PartyMemberInfo, PartyState};

        let mut s = UiScript::new().unwrap();
        assert_eq!(s.eval::<Option<i64>>("return IsInGroup()").unwrap(), None);
        assert_eq!(s.eval::<Option<i64>>("return IsInRaid()").unwrap(), None);

        s.set_party(PartyState {
            members: vec![PartyMemberInfo::default()],
            ..Default::default()
        });
        assert_eq!(
            s.eval::<i64>("return IsInGroup()").unwrap(),
            1,
            "a party counts as a group"
        );
        assert_eq!(
            s.eval::<Option<i64>>("return IsInRaid()").unwrap(),
            None,
            "but not as a raid"
        );
    }
}