class_name P93CoreLoopService
extends RefCounted

const State = preload("res://p9_3/core_loop_state.gd")
const BattleService = preload("res://domain/p9_2/battle_service.gd")

const OFFERS := {
	"Wayrunner": {
		"cost": 10,
		"name_zh": "托马斯 · 游侠",
		"name_en": "Tomas · Wayrunner",
		"strength_zh": "闪避后反击",
		"strength_en": "Counters after evading",
		"limit_zh": "正面承伤较低",
		"limit_en": "Lower direct durability",
	},
	"Farstring": {
		"cost": 12,
		"name_zh": "妮娅 · 弓手",
		"name_en": "Nia · Farstring",
		"strength_zh": "接触前远程射击",
		"strength_en": "Shoots before contact",
		"limit_zh": "被近身时脆弱",
		"limit_en": "Fragile at close range",
	},
	"Kindhand": {
		"cost": 11,
		"name_zh": "赛布尔 · 治疗",
		"name_en": "Sable · Kindhand",
		"strength_zh": "治疗受伤队员",
		"strength_en": "Heals wounded allies",
		"limit_zh": "直接伤害较低",
		"limit_en": "Low direct damage",
	},
}

const ENCOUNTERS := {
	"open_road": {
		"name_zh": "开阔旧道",
		"name_en": "Open Road",
		"reward": 8,
		"pressure_zh": "1 名近战",
		"pressure_en": "1 contact enemy",
		"seed": 9301,
	},
	"crosswind": {
		"name_zh": "侧风隘口",
		"name_en": "Crosswind Pass",
		"reward": 12,
		"pressure_zh": "近战 + 远程",
		"pressure_en": "Contact + ranged",
		"seed": 9302,
	},
	"bell_breach": {
		"name_zh": "钟门裂口",
		"name_en": "Bell Breach",
		"reward": 16,
		"pressure_zh": "近距离夹击",
		"pressure_en": "Close two-enemy pressure",
		"seed": 9303,
	},
}

const EQUIPMENT := {
	"EQ-002": {
		"name_zh": "钉阵胫甲",
		"name_en": "Frontpin Greaves",
		"wearer": "Hearthguard",
		"benefit_zh": "抵住钟门的第一次推位",
		"benefit_en": "Resists Bell Breach's first push",
		"cost_zh": "第一次攻击晚 1 tick",
		"cost_en": "First basic waits 1 tick",
	},
	"EQ-012": {
		"name_zh": "开线绳结",
		"name_en": "Open-Line Cord",
		"wearer": "Farstring",
		"benefit_zh": "被推到前方时抢射后排",
		"benefit_en": "Early rear shot after being pushed ahead",
		"cost_zh": "弓手暴露在最前方",
		"cost_en": "Farstring becomes the exposed lead",
	},
}

var state := State.new()
var battle := BattleService.new()
var bell_equipment_boundary_resolved := false


func enter_hall() -> Dictionary:
	if state.phase != State.Phase.TITLE:
		return _reject("title_required")
	state.phase = State.Phase.HALL
	state.revision += 1
	return _success("hall_entered")


func focus_offer(member_id: String) -> Dictionary:
	if state.phase != State.Phase.HALL:
		return _reject("hall_required")
	if member_id not in state.available_offers or not OFFERS.has(member_id):
		return _reject("offer_unavailable")
	state.focused_offer = member_id
	state.revision += 1
	return _success("offer_focused")


func hire(member_id: String) -> Dictionary:
	if state.phase != State.Phase.HALL:
		return _reject("hall_required")
	if member_id != state.focused_offer:
		return _reject("focus_required")
	if member_id not in state.available_offers or member_id in state.company:
		return _reject("offer_unavailable")
	if state.company.size() >= 10:
		return _reject("company_full")
	var cost := int(OFFERS[member_id].cost)
	if state.coin < cost:
		return _reject("insufficient_coin")
	var before := state.coin
	state.coin -= cost
	state.company.append(member_id)
	state.available_offers.erase(member_id)
	state.equipped_items[member_id] = ""
	state.member_levels[member_id] = 1
	state.member_xp[member_id] = 0
	state.focused_offer = ""
	state.hired_member = member_id
	state.phase = State.Phase.ENCOUNTER
	state.hire_receipts.append({
		"index": state.hire_receipts.size(),
		"member_id": member_id,
		"cost": cost,
		"coin_before": before,
		"coin_after": state.coin,
		"company_size": state.company.size(),
	})
	state.revision += 1
	return _success("hire_committed")


func select_encounter(encounter_id: String) -> Dictionary:
	if state.phase != State.Phase.ENCOUNTER:
		return _reject("encounter_phase_required")
	if not ENCOUNTERS.has(encounter_id):
		return _reject("unknown_encounter")
	state.selected_encounter = encounter_id
	state.revision += 1
	return _success("encounter_selected")


func start_battle() -> Dictionary:
	if state.phase != State.Phase.ENCOUNTER:
		return _reject("encounter_phase_required")
	if not ENCOUNTERS.has(state.selected_encounter):
		return _reject("encounter_required")
	var encounter: Dictionary = ENCOUNTERS[state.selected_encounter]
	var result: Dictionary = battle.start_fixture(state.company, int(encounter.seed))
	if not result.ok:
		return _reject(String(result.code))
	_apply_encounter_configuration(state.selected_encounter)
	bell_equipment_boundary_resolved = false
	state.phase = State.Phase.BATTLE
	state.reward_committed = false
	state.last_reward = 0
	state.last_outcome = ""
	state.revision += 1
	return {
		"ok": true,
		"code": "battle_started",
		"state": state.snapshot(),
		"battle": battle.state.current_snapshot(),
	}


func advance_battle_ticks(ticks := 1) -> Dictionary:
	if state.phase != State.Phase.BATTLE:
		return _reject("battle_required")
	if ticks < 0:
		var rejected: Dictionary = battle.advance_ticks(ticks)
		return {
			"ok": rejected.ok,
			"code": rejected.code,
			"events": rejected.events,
			"state": state.snapshot(),
			"battle": rejected.snapshot,
		}
	var events: Array[Dictionary] = []
	var result: Dictionary = battle.advance_ticks(0)
	for _tick in ticks:
		if state.phase != State.Phase.BATTLE:
			break
		for event in _resolve_bell_equipment_boundary():
			events.append(event)
		result = battle.advance_ticks(1)
		for event in result.events:
			events.append(event)
		if battle.state.terminal:
			state.phase = State.Phase.RESULT
			state.last_outcome = battle.state.outcome
			state.revision += 1
	return {
		"ok": result.ok,
		"code": result.code,
		"events": events,
		"state": state.snapshot(),
		"battle": result.snapshot,
	}


func claim_and_return() -> Dictionary:
	if state.phase != State.Phase.RESULT:
		return _reject("result_required")
	if state.last_outcome == "victory" and not state.reward_committed:
		var reward := int(ENCOUNTERS[state.selected_encounter].reward)
		var before := state.coin
		state.coin += reward
		state.last_reward = reward
		state.reward_committed = true
		state.reward_receipts.append({
			"index": state.reward_receipts.size(),
			"encounter_id": state.selected_encounter,
			"reward": reward,
			"coin_before": before,
			"coin_after": state.coin,
		})
		_grant_battle_xp(state.reward_receipts.size())
	state.phase = State.Phase.HALL
	state.selected_encounter = ""
	state.revision += 1
	return _success("returned_to_hall")


func offer(member_id: String) -> Dictionary:
	return Dictionary(OFFERS.get(member_id, {})).duplicate(true)


func encounter(encounter_id: String) -> Dictionary:
	return Dictionary(ENCOUNTERS.get(encounter_id, {})).duplicate(true)


func equipment(item_id: String) -> Dictionary:
	return Dictionary(EQUIPMENT.get(item_id, {})).duplicate(true)


func equipment_choice_available() -> bool:
	return state.phase == State.Phase.HALL and state.reward_receipts.size() == 2 and state.equipment_receipts.is_empty()


func focus_equipment(item_id: String) -> Dictionary:
	if not equipment_choice_available():
		return _reject("equipment_choice_unavailable")
	if not EQUIPMENT.has(item_id):
		return _reject("unknown_equipment")
	state.focused_equipment = item_id
	state.revision += 1
	return _success("equipment_focused")


func equip_focused(member_id: String) -> Dictionary:
	if not equipment_choice_available():
		return _reject("equipment_choice_unavailable")
	if not EQUIPMENT.has(state.focused_equipment):
		return _reject("equipment_focus_required")
	var item_id := state.focused_equipment
	if member_id != String(EQUIPMENT[item_id].wearer) or member_id not in state.company:
		return _reject("incompatible_wearer")
	if not String(state.equipped_items.get(member_id, "")).is_empty():
		return _reject("equipment_slot_occupied")
	state.equipped_items[member_id] = item_id
	state.equipment_receipts.append({
		"index": state.equipment_receipts.size(),
		"item_id": item_id,
		"member_id": member_id,
		"returned_item_id": "",
	})
	state.focused_equipment = ""
	state.phase = State.Phase.ENCOUNTER
	state.revision += 1
	return _success("equipment_committed")


func _apply_encounter_configuration(encounter_id: String) -> void:
	match encounter_id:
		"open_road":
			battle.state.enemy_hp["RiftSpitter"] = 0
		"bell_breach":
			battle.state.enemy_positions["RiftBulwark"] = 72
			battle.state.enemy_positions["RiftSpitter"] = 84
	battle.state.event_log.append({
		"index": battle.state.event_log.size(),
		"tick": battle.state.tick,
		"kind": "encounter_configured",
		"encounter_id": encounter_id,
		"reward": int(ENCOUNTERS[encounter_id].reward),
	})
	battle.state.revision += 1
	assert(battle.state.invariants_hold())


func _resolve_bell_equipment_boundary() -> Array[Dictionary]:
	var events: Array[Dictionary] = []
	if bell_equipment_boundary_resolved or state.selected_encounter != "bell_breach" or battle.state.tick != 15:
		return events
	var item_id := String(state.equipped_items.get("Hearthguard", ""))
	if item_id.is_empty():
		item_id = String(state.equipped_items.get("Farstring", ""))
	if item_id not in ["EQ-002", "EQ-012"]:
		return events
	bell_equipment_boundary_resolved = true
	if item_id == "EQ-002":
		battle.state.member_next_action_tick["Hearthguard"] = 17
		events.append(_append_battle_event("equipment_trigger", {
			"source_member_id": "Hearthguard",
			"item_id": item_id,
			"qualifier_en": "push resisted",
			"cue": "guard",
		}))
	else:
		if battle.state.member_ids.size() < 2 or battle.state.member_ids[0] != "Hearthguard" or battle.state.member_ids[1] != "Farstring":
			return events
		battle.state.member_ids[0] = "Farstring"
		battle.state.member_ids[1] = "Hearthguard"
		battle.state.member_positions["Farstring"] = 32
		battle.state.member_positions["Hearthguard"] = 20
		if battle.state.member_ids.size() > 2:
			battle.state.member_positions[battle.state.member_ids[2]] = 8
		battle.state.enemy_positions["RiftBulwark"] = 40
		events.append(_append_battle_event("line_push", {
			"source_enemy_id": "RiftBulwark",
			"moved_member_id": "Hearthguard",
			"exposed_member_id": "Farstring",
			"qualifier_en": "line pushed",
			"cue": "push",
		}))
		var before := int(battle.state.enemy_hp.RiftSpitter)
		battle.state.enemy_hp.RiftSpitter = maxi(0, before - 14)
		battle.state.member_next_action_tick["Farstring"] = 28
		events.append(_append_battle_event("member_action", {
			"source_member_id": "Farstring",
			"target_enemy_id": "RiftSpitter",
			"delta": -mini(14, before),
			"item_id": item_id,
			"qualifier_en": "extended shot",
			"cue": "hit",
		}))
	battle.state.revision += 1
	assert(battle.state.invariants_hold())
	return events


func _append_battle_event(kind: String, payload: Dictionary) -> Dictionary:
	var event: Dictionary = {
		"index": battle.state.event_log.size(),
		"tick": battle.state.tick,
		"kind": kind,
	}
	for key in payload:
		event[key] = payload[key]
	battle.state.event_log.append(event)
	return event


func _grant_battle_xp(round_index: int) -> void:
	var grant := 10 + 2 * round_index
	var rows: Array[Dictionary] = []
	for member_id in battle.state.living_member_ids():
		var level := int(state.member_levels.get(member_id, 1))
		var xp := int(state.member_xp.get(member_id, 0)) + grant
		var levels_gained := 0
		while level < 10:
			var threshold := 20 + 10 * level
			if xp < threshold:
				break
			xp -= threshold
			level += 1
			levels_gained += 1
		if level >= 10:
			xp = 0
		state.member_levels[member_id] = level
		state.member_xp[member_id] = xp
		rows.append({
			"member_id": member_id,
			"grant": grant,
			"level": level,
			"xp": xp,
			"levels_gained": levels_gained,
		})
	state.xp_receipts.append({
		"index": state.xp_receipts.size(),
		"round": round_index,
		"grant": grant,
		"members": rows,
	})


func _success(code: String) -> Dictionary:
	assert(state.invariants_hold())
	return {"ok": true, "code": code, "state": state.snapshot()}


func _reject(code: String) -> Dictionary:
	assert(state.invariants_hold())
	return {"ok": false, "code": code, "state": state.snapshot()}