extends Node
## Autoload for local persistence (JSON in user://). Wrapped in an autoload so UI
## nodes never touch the filesystem directly.

const SHIFT_RESULTS_FILE := "shift_results.json"
const SETTINGS_FILE := "settings.json"
const CAMPAIGN_FILE := "campaign.json"
const SHIFT_STATE_FILE := "shift_state.json"

func _load_json(file_name: String) -> Variant:
	var path := "user://" + file_name
	if not FileAccess.file_exists(path):
		return null
	var text := FileAccess.get_file_as_string(path)
	if text.is_empty():
		return null
	var parsed = JSON.parse_string(text)
	return parsed

func _save_json(file_name: String, data: Variant) -> Error:
	var path := "user://" + file_name
	var temp := path + ".tmp"
	var text := JSON.stringify(data, "\t")
	var f := FileAccess.open(temp, FileAccess.WRITE)
	if f == null:
		return FileAccess.get_open_error()
	f.store_string(text)
	f.close()
	# Replace the target only after the complete JSON has been written, so a
	# crash cannot leave a partial save in place.
	return DirAccess.rename_absolute(ProjectSettings.globalize_path(temp),
		ProjectSettings.globalize_path(path))

## Load previous shift results. Returns Array of Dictionaries or [].
func load_shift_results() -> Array:
	var data = _load_json(SHIFT_RESULTS_FILE)
	if data is Array:
		return data
	return []

## Append one shift result and save. Returns Error.
func save_shift_result(result: Dictionary) -> Error:
	var results := load_shift_results()
	results.append(result)
	return _save_json(SHIFT_RESULTS_FILE, results)

## Campaign/session progression (separate from settings and shift history).
func load_campaign() -> Dictionary:
	var data = _load_json(CAMPAIGN_FILE)
	return data if data is Dictionary else {}

func save_campaign(data: Dictionary) -> Error:
	return _save_json(CAMPAIGN_FILE, data)

func reset_campaign() -> Error:
	return _save_json(CAMPAIGN_FILE, {})

## Mid-shift checkpoint. Kept separate so a completed shift history is never
## overwritten by a resumable snapshot.
func load_shift_state() -> Dictionary:
	var data = _load_json(SHIFT_STATE_FILE)
	return data if data is Dictionary else {}

func save_shift_state(data: Dictionary) -> Error:
	return _save_json(SHIFT_STATE_FILE, data)

func clear_shift_state() -> Error:
	return _save_json(SHIFT_STATE_FILE, {})

## Defaults for player settings. Kept in code so a missing or partial
## settings.json still produces a usable config.
const DEFAULT_SETTINGS := {
	"look_sensitivity": 0.0022,
	"hud_font_scale": 1.0,
	"invert_y": false,
	"head_bob": true,
	"input_bindings": {},
	"ai_difficulty": "normal",
	"tutorial_completed": false,
	"tutorial_skipped": false,
	"master_volume": 1.0,
	"sfx_volume": 1.0,
	"ambience_volume": 1.0,
	"reduce_motion": false,
	"captions_enabled": true,
}

## Load player settings, merged over the defaults. Returns a Dictionary.
func load_settings() -> Dictionary:
	var merged: Dictionary = DEFAULT_SETTINGS.duplicate(true)
	var data = _load_json(SETTINGS_FILE)
	if data is Dictionary:
		for key in data.keys():
			if merged.has(key):
				merged[key] = data[key]
	return merged

## Persist player settings. Returns Error.
func save_settings(settings: Dictionary) -> Error:
	var merged: Dictionary = DEFAULT_SETTINGS.duplicate(true)
	for key in settings.keys():
		if merged.has(key):
			merged[key] = settings[key]
	return _save_json(SETTINGS_FILE, merged)