///- --package .
:# hunt_sim static =
    :< testing

:== tile = geometry::position

:== foe_kind = creatures::arena_creature

:= tick_ms () : i32 = 100
:= scenario_ticks () : i32 = 3000
:= spawn_health (foe : foe_kind) : i32 =
    (creatures::stats_of foe)::max_health

:= creature_melee_max (foe : foe_kind) : u32 =
    conv (creatures::stats_of foe)::melee_max

:= default_foe () : foe_kind =
    :< creatures
    Troll

:== offense = { level : i32; weapon_attack : i32; weapon_skill : i32; step_ms : i32 }

:= offense_of (level : i32) (attack : i32) (skill : i32) : offense =
    { level = level; weapon_attack = attack; weapon_skill = skill; step_ms = hunting_pack::knight_sample_step_ms () }

:= offense_against (foe : foe_kind) : offense =
    :< creatures
    ?= foe ?|
    | Cyclops => offense_of 30 21 60
    | _ => offense_of 8 20 30

:= swinger_of (o : offense) : combat::swinger =
    {
        mode =
            :< damage
            Balanced
        level = o::level
        attack_value = o::weapon_attack
        attack_skill = o::weapon_skill
    }

:< keyed_rng

:| hunt_roll =
    | PlayerHit
    | PlayerHeal
    | CreatureHit
    | Loot
    | Policy

:+ purpose_code hunt_roll =
    \ r =>
        ?= r ?|
        | PlayerHit => 1u32
        | PlayerHeal => 2u32
        | CreatureHit => 3u32
        | Loot => 4u32
        | Policy => 5u32

:= player_hit (foe : foe_kind) (roll : keyed_rng::roll_key hunt_roll) : i32 =
    := stats = creatures::stats_of foe
    combat::melee_hit (swinger_of (offense_against foe)) { armor = stats::armor; defense = stats::defense } roll

:= creature_strike_ms () : i32 = 2000
:= heal_below () : i32 = 60


:== knight_state = { at : tile; health : i32; timers : cooldowns::timers; next_step_at : i32 }

:== living = vitality::vitality vitality::alive

:== foe_state = { at : tile; life : living; strikes_at : i32; next_step_at : i32; met_player : bool }

:== hunt = { player : knight_state; creature : foe_state; kills : i32; gold : i32; escapes : i32 }

:== moment = { seed : u32; tick : i32; now : i32 }

:= spawn_point () : tile = geometry::position 106 103 7

:= knight_start () : knight_state =
    { at = geometry::position 100 100 7; health = 150; timers = cooldowns::idle_timers (); next_step_at = 0 }

:= foe_start (foe : foe_kind) : foe_state =
    {
        at = spawn_point ()
        life = vitality::spawn (spawn_health foe)
        strikes_at = 0
        next_step_at = 0
        met_player = !-
    }

:= start (foe : foe_kind) : hunt =
    { player = knight_start (); creature = foe_start foe; kills = 0; gold = 0; escapes = 0 }

:= key (m : moment) (purpose : hunt_roll) : keyed_rng::roll_key hunt_roll =
    keyed_rng::roll_key (keyed_rng::seed m::seed) (keyed_rng::tick (conv m::tick)) (keyed_rng::entity 1u32) purpose

:= adjacent (s : hunt) : bool =
    geometry::within_range 1 s::player::at s::creature::at

:= escape_distance () : i32 = 8

:= respawned_foe (foe : foe_kind) (c : foe_state) : foe_state =
    { c ?| at = spawn_point (); life = vitality::spawn (spawn_health foe); met_player = !- }

:= fled_from (foe : foe_kind) (now : i32) (player_at : tile) (c : foe_state) : foe_state =
    := away = geometry::step_away player_at c::at
    { c ?| at = away; next_step_at = now + geometry::step_cost (creatures::stats_of foe)::step_ms c::at away }

:= escaped (foe : foe_kind) (fled : foe_state) (s : hunt) : hunt =
    { s ?| creature = respawned_foe foe fled; escapes = s::escapes + 1 }

:= flee (foe : foe_kind) (now : i32) (s : hunt) : hunt =
    := fled = fled_from foe now s::player::at s::creature
    ? geometry::chebyshev_distance s::player::at fled::at >= escape_distance () ?> escaped foe fled s
    |: { s ?| creature = fled }

:= creature_step_ms (foe : foe_kind) (met_player : bool) : i32 =
    := step = (creatures::stats_of foe)::step_ms
    ? met_player ?> step * hunting_pack::chase_step_factor () |: step

:= approached (foe : foe_kind) (now : i32) (player_at : tile) (c : foe_state) : foe_state =
    := toward = geometry::step_toward player_at c::at
    { c ?| at = toward; next_step_at = now + geometry::step_cost (creature_step_ms foe c::met_player) c::at toward }

:= met (c : foe_state) : foe_state = { c ?| met_player = !+ }

:= fleeing (foe : foe_kind) (c : foe_state) : bool = vitality::health c::life < (creatures::stats_of foe)::run_health

:= creature_moves (foe : foe_kind) (now : i32) (s : hunt) : hunt =
    := c = s::creature
    ? now < c::next_step_at ?> s
    |? fleeing foe c ?> flee foe now s
    |: { s ?| creature = (? adjacent s ?> met c |: approached foe now s::player::at c) }

:= creature_damage (foe : foe_kind) (m : moment) : i32 =
    := roll = key m CreatureHit
    combat::creature_hit (conv (creature_melee_max foe)) (combat::knight_sample_gear ()) !+ roll

:= struck_by (damage : i32) (now : i32) (s : hunt) : hunt =
    := p, c = s::player, s::creature
    { s ?| player = { p ?| health = p::health - damage }; creature = { c ?| strikes_at = now + creature_strike_ms () } }

:= creature_strikes (foe : foe_kind) (m : moment) (s : hunt) : hunt =
    ? adjacent s && s::creature::strikes_at <= m::now ?> struck_by (creature_damage foe m) m::now s |: s

:= heal_spell () = vocations::as_cooldown (vocations::knight_heal ())

:= healed (amount : i32) (now : i32) (p : knight_state) : knight_state =
    { p ?| health = p::health + amount; timers = cooldowns::after_cast now (heal_spell ()) p::timers }

:= heal_now (m : moment) (s : hunt) : hunt =
    := amount : i32 = conv (keyed_rng::roll_between 30 60 (key m PlayerHeal))
    { s ?| player = healed amount m::now s::player }

:= struck (now : i32) (p : knight_state) : knight_state =
    { p ?| timers = cooldowns::after_cast now (cooldowns::strike_spell ()) p::timers }

:= looted (foe : foe_kind) (bounty : i32) (s : hunt) : hunt =
    { s ?| creature = respawned_foe foe s::creature; kills = s::kills + 1; gold = s::gold + bounty }

:= bounty (m : moment) : i32 = conv (keyed_rng::roll_between 10 30 (key m Loot))

:= after_hit (foe : foe_kind) (m : moment) (damage : i32) (s : hunt) : hunt =
    :< vitality
    := c = s::creature
    ?= strike damage c::life ?|
    | Survived wounded => { s ?| creature = { c ?| life = wounded } }
    | Slain _ => looted foe (bounty m) s

:= strike_now (foe : foe_kind) (m : moment) (s : hunt) : hunt =
    := damage = player_hit foe (key m PlayerHit)
    after_hit foe m damage { s ?| player = struck m::now s::player }

:= heal_ready (now : i32) (p : knight_state) : bool = cooldowns::can_cast now (heal_spell ()) p::timers

:= strike_ready (now : i32) (p : knight_state) : bool = cooldowns::can_cast now (cooldowns::strike_spell ()) p::timers

:= observe (now : i32) (s : hunt) : policy::observation =
    :< policy
    {
        health = s::player::health
        heal_ready = heal_ready now s::player
        strike_ready = strike_ready now s::player
        target = ? adjacent s ?> InReach |: OutOfReach
    }

:= player_heals_below (threshold : i32) (m : moment) (s : hunt) : hunt =
    ? s::player::health < threshold && heal_ready m::now s::player ?> heal_now m s |: s

:= player_strikes (foe : foe_kind) (m : moment) (s : hunt) : hunt =
    ? adjacent s && strike_ready m::now s::player ?> strike_now foe m s |: s

:= stepped_toward (target : tile) (step_ms : i32) (now : i32) (p : knight_state) : knight_state =
    := toward = geometry::step_toward target p::at
    { p ?| at = toward; next_step_at = now + geometry::step_cost step_ms p::at toward }

:= player_approaches (foe : foe_kind) (now : i32) (s : hunt) : hunt =
    ? now < s::player::next_step_at || adjacent s ?> s
    |: { s ?| player = stepped_toward s::creature::at (offense_against foe)::step_ms now s::player }

:= engaged (foe : foe_kind) (t : policy::thresholds) (m : moment) (s : hunt) : hunt =
    :< policy
    ?= engages t (observe m::now s) ?|
    | Strike => strike_now foe m s
    | Approach => player_approaches foe m::now s
    | Hold => s

:= follow_policy (foe : foe_kind) (t : policy::thresholds) (m : moment) (s : hunt) : hunt =
    :< policy
    engaged foe t m (? heals t (observe m::now s) ?> heal_now m s |: s)

:| policy =
    | Scripted
    | ScriptedHealingBelow : i32
    | Tuned : i32 * i32
    | RandomControl


:= cavebot_baseline () : policy = Tuned (120, 0)

:= scripted_act (foe : foe_kind) (threshold : i32) (m : moment) (s : hunt) : hunt =
    s |> player_heals_below threshold m |> player_strikes foe m

:= random_act (foe : foe_kind) (m : moment) (s : hunt) : hunt =
    := pick = keyed_rng::roll_between 0 2 (key m Policy)
    ? pick = 1 ?> player_heals_below 100000 m s |? pick = 2 ?> player_strikes foe m s |: s

:= tuned_act (foe : foe_kind) (heal : i32) (strike : i32) (m : moment) (s : hunt) : hunt =
    follow_policy foe { heal_below = heal; strike_above = strike } m s

:= scripted_threshold (choice : policy) : i32 =
    ?= choice ?|
    | ScriptedHealingBelow threshold => threshold
    | _ => heal_below ()

:= player_acts (foe : foe_kind) (choice : policy) (m : moment) (s : hunt) : hunt =
    ?= choice ?|
    | Tuned (heal, strike) => tuned_act foe heal strike m s
    | RandomControl => random_act foe m s
    | _ => scripted_act foe (scripted_threshold choice) m s

:= creature_turn_then_player (foe : foe_kind) (choice : policy) (m : moment) (s : hunt) : hunt =
    := struck = s |> creature_moves foe m::now |> creature_strikes foe m
    ? struck::player::health <= 0 ?> struck |: player_acts foe choice m struck

:= advance_against (foe : foe_kind) (choice : policy) (seed : u32) (tick : i32) (s : hunt) : hunt =
    := m = { seed = seed; tick = tick; now = tick * tick_ms () }
    ? s::player::health <= 0 ?> s |: creature_turn_then_player foe choice m s

:~ ^ simulated_from (foe : foe_kind) (choice : policy) (seed : u32) (ticks : i32) (tick : i32) (s : hunt) : hunt =
    ? tick >= ticks ?> s |: simulated_from foe choice seed ticks (tick + 1) (advance_against foe choice seed tick s)

:= simulate_against (foe : foe_kind) (choice : policy) (seed : u32) (ticks : i32) : hunt =
    simulated_from foe choice seed ticks 0 (start foe)

:= simulate_with (choice : policy) (seed : u32) (ticks : i32) : hunt =
    simulate_against (default_foe ()) choice seed ticks

:= simulate (seed : u32) (ticks : i32) : hunt =
    simulate_with Scripted seed ticks

:== trial = { foe : foe_kind; first : u32; count : i32 }

:= trial_hunt (t : trial) (choice : policy) (index : i32) : hunt =
    simulate_against t::foe choice (t::first + conv index) (scenario_ticks ())

:= summed (f : hunt -> i32) (t : trial) (choice : policy) : i32 =
    :~ ^ go (index : i32) (acc : i32) : i32 =
        ? index >= t::count ?> acc |: go (index + 1) (acc + f (trial_hunt t choice index))
    go 0 0

:= died (h : hunt) : i32 = ? h::player::health <= 0 ?> 1 |: 0

:= total_deaths_against (foe : foe_kind) (choice : policy) (first_seed : u32) (count : i32) : i32 =
    summed died { foe = foe; first = first_seed; count = count } choice

:= total_kills (choice : policy) (first_seed : u32) (count : i32) : i32 =
    summed (\ h => h::kills) { foe = default_foe (); first = first_seed; count = count } choice

:= total_deaths (choice : policy) (first_seed : u32) (count : i32) : i32 =
    total_deaths_against (default_foe ()) choice first_seed count

///> c
:# same_seed_same_hunt =
    := ~seed = 7u32
    := a, b = simulate seed (scenario_ticks ()), simulate seed (scenario_ticks ())
    (a::kills, a::gold, a::player::health) |> _assert_eq (b::kills, b::gold, b::player::health)

///> c
:# chasing_hunter_survives_and_kills =
    := ~seed = 7u32
    := outcome = simulate_with (cavebot_baseline ()) seed (scenario_ticks ())
    (outcome::kills > 0, outcome::player::health > 0) |> _assert_eq (!+, !+)

///> c
:# loot_stays_within_bounty_range =
    := ~seed = 7u32
    := outcome = simulate seed (scenario_ticks ())
    (outcome::gold >= outcome::kills * 10, outcome::gold <= outcome::kills * 30) |> _assert_eq (!+, !+)

///> rust
///> c
:# golden_seed_7 =
    := ~seed = 7u32
    := outcome = simulate seed (scenario_ticks ())
    (outcome::kills, outcome::gold, outcome::player::health) |> _assert_eq (1i32, 18i32, 150i32)

///> c
:# scripted_beats_random_control_over_twenty_seeds =
    := ~first = 1u32
    := scripted, control = total_kills Scripted first 20, total_kills RandomControl first 20
    (scripted, control, scripted > control) |> _assert_eq (34i32, 28i32, !+)

:= sweep_kills (first : u32) (threshold : i32) : i32 = total_kills (ScriptedHealingBelow threshold) first 10

///> c
:# heal_threshold_sweep_over_ten_seeds =
    := ~first = 1u32
    := at = sweep_kills first
    (at 20, at 40, at 60, at 80, at 100, at 120) |> _assert_eq (14i32, 14i32, 14i32, 14i32, 14i32, 14i32)

:= sweep_deaths (first : u32) (threshold : i32) : i32 = total_deaths (ScriptedHealingBelow threshold) first 10

///> c
:# troll_scenario_saturates_no_deaths_over_ten_seeds =
    := ~first = 1u32
    := at = sweep_deaths first
    (at 20, at 60, at 120, total_deaths RandomControl first 10) |> _assert_eq (0i32, 0i32, 0i32, 0i32)

:= cyclops_deaths (first : u32) (choice : policy) : i32 =
    :< creatures
    total_deaths_against Cyclops choice first 10

///> c
:# cyclops_scenario_separates_policies_over_ten_seeds =
    := ~first = 1u32
    := deaths = cyclops_deaths first
    (deaths (ScriptedHealingBelow 120), deaths (ScriptedHealingBelow 20), deaths RandomControl)
    |> _assert_eq (0i32, 10i32, 0i32)

///> wgsl
:# golden_seed_7_on_gpu =
    := ~seed = 7u32
    := outcome = simulate seed (scenario_ticks ())
    ? outcome::kills = 1i32 && outcome::gold = 18i32 && outcome::player::health = 150i32 ?> 0i32 |: 1i32

///> wgsl
:# scripted_beats_random_control_on_gpu =
    := ~first = 1u32
    ? total_kills Scripted first 20 = 34i32 && total_kills RandomControl first 20 = 28i32 ?> 0i32 |: 1i32

///> c
:# chasing_policy_outkills_standing_scripted_over_twenty_seeds =
    := ~first = 1u32
    := standing, chasing = total_kills Scripted first 20, total_kills (Tuned (60, 40)) first 20
    (standing, chasing, chasing > standing) |> _assert_eq (34i32, 356i32, !+)