# SaveManager.gd (добавить в AutoLoad)
extends Node

# ~/Library/Application Support/Godot/app_userdata/Owniverse Adventure/savegame.cfg
const SETTING_SECTION := "Settings"
const SAVE_PATH = "user://settings.cfg"

const FORMAT_VERSION: int = 2
const SimulationTime = preload("res://world/owniverse/simulation_time.gd")
const WorldParameters = preload("res://world/owniverse/world_parameters.gd")
const STATE_VERSION: String = SimulationTime.STATE_VERSION
var last_error: String = ""
var blocked_saves: Dictionary = {}
var save_directory: String = "user://"
signal save_completed(filename: String, success: bool, error: String)
signal saves_drained

# Queue ownership stays on the main thread. The worker only sees its snapshot.
var _save_thread: Thread
var _active_filename: String = ""
var _pending_saves: Dictionary = {}


func _process(_delta: float) -> void:
    if _save_thread != null and not _save_thread.is_alive():
        _finish_save()


func is_saving() -> bool:
    return _save_thread != null or not _pending_saves.is_empty()


func _snapshot(filename: String, password: String, data: Dictionary) -> Dictionary:
    var payload: Dictionary = data.duplicate(true)
    payload.format_version = FORMAT_VERSION
    payload.app_version = str(ProjectSettings.get_setting("application/config/version", ""))
    return {"filename": filename, "path": save_directory.path_join(filename + ".adventure"), "password": password, "payload": payload,
        "plaintext": Global.save_plaintext_copy, "speed_limit": Global.SPEED_LIMIT,
        "stages": Global.CivilizationRules.keys()}


## True means queued, not written. Completion is reported by save_completed.
func request_save(filename: String, password: String, data: Dictionary) -> bool:
    if blocked_saves.has(filename):
        return _fail("Save blocked to preserve an unreadable save: " + filename)
    _pending_saves[filename] = _snapshot(filename, password, data)
    if _save_thread == null:
        _start_save()
    return true


func _start_save() -> void:
    if _pending_saves.is_empty():
        return
    _active_filename = _pending_saves.keys()[0]
    var job: Dictionary = _pending_saves[_active_filename]
    _pending_saves.erase(_active_filename)
    _save_thread = Thread.new()
    var error: Error = _save_thread.start(_write_snapshot.bind(job))
    if error != OK:
        _save_thread = null
        _fail("Cannot start save worker: " + error_string(error))
        save_completed.emit(_active_filename, false, last_error)
        _start_save()
        if not is_saving(): saves_drained.emit()


func _finish_save() -> void:
    var error: String = _save_thread.wait_to_finish()
    var filename: String = _active_filename
    _save_thread = null
    last_error = error
    if error != "": push_error(error)
    save_completed.emit(filename, error == "", error)
    if _save_thread == null: _start_save()
    if not is_saving(): saves_drained.emit()


## Used for application suspension and teardown, when frames may stop arriving.
func flush_saves() -> void:
    while is_saving():
        if _save_thread == null: _start_save()
        if _save_thread != null: _finish_save()


func _exit_tree() -> void:
    flush_saves()

#region Save Load routines

func _fail(message: String) -> bool:
    last_error = message
    push_error(message)
    return false


func save_data(filename: String, password: String, data: Dictionary) -> bool:
    # Synchronous compatibility API must never race an asynchronous writer.
    flush_saves()
    last_error = ""
    if blocked_saves.has(filename):
        return _fail("Save blocked to preserve an unreadable save: " + filename)
    var error: String = _write_snapshot(_snapshot(filename, password, data))
    return _fail(error) if error != "" else true


static func _write_snapshot(job: Dictionary) -> String:
    var payload: Dictionary = job.payload
    var problem: String = _validate_payload(payload, job.speed_limit, job.stages)
    if problem != "":
        return "Invalid save: " + problem
    var path: String = job.path
    var temporary: String = path + ".tmp"
    var file := FileAccess.open_encrypted_with_pass(temporary, FileAccess.WRITE, job.password)
    if file == null:
        return "Cannot write encrypted save: " + temporary
    file.store_var(payload, false)
    file.close()
    # Check the actual encrypted file, including finalization, before replacing the old save.
    var verification := FileAccess.open_encrypted_with_pass(temporary, FileAccess.READ, job.password)
    if verification == null:
        return "Cannot verify encrypted save: " + temporary
    var restored: Variant = verification.get_var(false)
    verification.close()
    if not restored is Dictionary or restored != payload:
        return "Encrypted save verification failed: " + temporary
    if DirAccess.rename_absolute(temporary, path) != OK:
        return "Cannot replace encrypted save: " + path
    if job.plaintext:
        var plain_path: String = path + ".json"
        file = FileAccess.open(plain_path + ".tmp", FileAccess.WRITE)
        if file == null:
            return "Encrypted save written, but cannot write diagnostic copy: " + plain_path
        file.store_string(JSON.stringify(payload, "  ", true, true) + "\n")
        file.flush()
        var write_error: Error = file.get_error()
        file.close()
        if write_error != OK or DirAccess.rename_absolute(plain_path + ".tmp", plain_path) != OK:
            return "Encrypted save written, but diagnostic copy failed: " + plain_path
    return ""


func load_data(filename: String, password: String) -> Dictionary:
    flush_saves()
    last_error = ""
    # Plaintext is diagnostic only: never use it as a fallback.
    var path: String = save_directory.path_join(filename + ".adventure")
    if not FileAccess.file_exists(path):
        return {}
    var file := FileAccess.open_encrypted_with_pass(path, FileAccess.READ, password)
    if file == null:
        blocked_saves[filename] = true
        _fail("Cannot decrypt save: " + path)
        return {}
    var data: Variant = file.get_var(false)
    file.close()
    # Unsupported formats are archived, never converted or overwritten.
    # Returning no data lets the stage start a new, saveable session.
    if data is Dictionary and data.get("format_version") != FORMAT_VERSION:
        var archive: String = path + ".incompatible.bak"
        var index: int = 0
        while FileAccess.file_exists(archive):
            index += 1
            archive = path + ".incompatible.bak." + str(index)
        var error: Error = DirAccess.rename_absolute(path, archive)
        if error != OK:
            blocked_saves[filename] = true
            _fail("Cannot archive incompatible save: " + error_string(error))
            return {}
        blocked_saves.erase(filename)
        push_warning("Incompatible save preserved at " + archive + "; starting a new game.")
        return {}
    var problem: String = validate_data(data)
    if problem != "":
        blocked_saves[filename] = true
        _fail("Invalid save " + path + ": " + problem)
        return {}
    blocked_saves.erase(filename)
    return data


static func _number(value: Variant, whole: bool = false, nonnegative: bool = true) -> bool:
    if not (value is int or value is float) or not is_finite(float(value)):
        return false
    return (not whole or float(value) == floorf(float(value))) and (not nonnegative or value >= 0)


static func _number_map(value: Variant, whole: bool = false, nonnegative: bool = true) -> bool:
    if not value is Dictionary:
        return false
    for key in value:
        if not (key is String or key is StringName) or not _number(value[key], whole, nonnegative):
            return false
    return true


static func _plain_tree(value: Variant) -> bool:
    if value is Dictionary:
        for key in value:
            if not (key is String or key is StringName) or not _plain_tree(value[key]):
                return false
        return true
    if value is Array:
        for item in value:
            if not _plain_tree(item):
                return false
        return true
    return value == null or value is String or value is StringName or value is bool or _number(value, false, false)


## Return a diagnostic path on failure; an empty string means the structure is valid.
func validate_data(data: Variant) -> String:
    return _validate_payload(data, Global.SPEED_LIMIT, Global.CivilizationRules.keys())


static func _validate_payload(data: Variant, speed_limit: int, stages: Array) -> String:
    if not data is Dictionary or not _plain_tree(data):
        return "save must contain plain finite values"
    if data.get("format_version") != FORMAT_VERSION or not data.get("app_version") is String:
        return "unsupported save format"
    if not data.get("ui") is Dictionary or not data.ui.get("current_page") is int or data.ui.current_page < 0:
        return "invalid ui.current_page"
    if not data.get("state") is Dictionary:
        return "state must be a Dictionary"
    var saved: Dictionary = data.state
    var required := [
        "version", "time", "speed", "speed_in_year", "energy", "batches", "batch_origins",
        "binds", "amount", "distribution", "auto_resources", "auto_star_deficits",
        "production_remainders", "resource_remainders", "evolution_remainders", "life_remainders",
        "planet_remainders", "blast_remainders", "destruction_remainders", "civilization_remainders",
        "civilization_stats", "civilization_homes", "ethics", "stats",
    ]
    # Optional additions to the current format. Saves predating indicators keep
    # their quantities and receive neutral defaults from Owniverse on load.
    for field in saved:
        if field not in required and field not in ["world_parameters", "trends"]:
            return "unsupported state structure"
    if saved.has("world_parameters"):
        if not _number_map(saved.world_parameters) or saved.world_parameters.size() != WorldParameters.defaults().size():
            return "invalid state.world_parameters"
        for key in WorldParameters.defaults():
            if not saved.world_parameters.has(key) or saved.world_parameters[key] < 1.0:
                return "invalid world parameter " + key
            if key in ["Bur", "Exp", "Agg"] and saved.world_parameters[key] > 19.0:
                return "invalid world scale " + key
    if saved.has("trends"):
        if not _number_map(saved.trends) or saved.trends.size() != WorldParameters.TRENDS.size():
            return "invalid state.trends"
        for key in WorldParameters.TRENDS:
            if not saved.trends.has(key) or saved.trends[key] >= 1.0:
                return "invalid trend " + key
    for field in required:
        if not saved.has(field):
            return "missing state." + field
    if saved.version != STATE_VERSION:
        return "unsupported state.version"
    if not saved.time is Dictionary or not _number(saved.time.get("datetime")) or not _number(saved.time.get("year")):
        return "invalid state.time"
    if not is_finite(float(saved.time.datetime) * 10.0) or saved.time.year != SimulationTime.processed_year(saved.time.datetime):
        return "invalid processed time"
    if not _number(saved.speed, true) or saved.speed < 1 or saved.speed > speed_limit:
        return "invalid state.speed"
    if not _number(saved.speed_in_year) or saved.speed_in_year != pow(10.0, saved.speed - 1):
        return "invalid state.speed_in_year"
    if not _number(saved.energy, true) or not _number_map(saved.amount, true):
        return "invalid state resources"
    if not saved.stats is Dictionary or not _number_map(saved.stats.get("total_amount"), true):
        return "invalid state.stats.total_amount"
    if saved.amount.keys() != saved.stats.total_amount.keys():
        return "amount and total_amount keys differ"
    if not saved.binds is Dictionary or not saved.batches is Dictionary:
        return "state.binds and state.batches must be Dictionaries"
    for owner_id in saved.binds:
        if not saved.amount.has(owner_id) or not _number_map(saved.binds[owner_id], true):
            return "invalid state.binds." + owner_id
        for id in saved.binds[owner_id]:
            if not saved.amount.has(id):
                return "unknown bound resource " + id
    for id in saved.batches:
        if not saved.amount.has(id) or not saved.batches[id] is Array:
            return "invalid state.batches." + id
        for batch in saved.batches[id]:
            if not batch is Dictionary or not _number(batch.get("amount"), true) or not _number(batch.get("start_year")) or not _number(batch.get("end_year")):
                return "invalid batch in " + id
            if batch.end_year < batch.start_year:
                return "reversed batch interval in " + id
            if batch.has("created_from") != batch.has("created_to"):
                return "incomplete batch creation interval in " + id
            if batch.has("created_from") and (not _number(batch.created_from) or not _number(batch.created_to) or batch.created_to <= batch.created_from or batch.start_year < batch.created_from):
                return "invalid batch creation interval in " + id
            if batch.has("processed_until") and (not _number(batch.processed_until) or batch.processed_until < batch.start_year or batch.processed_until > batch.end_year):
                return "invalid batch.processed_until in " + id
            if batch.has("withdraw_remainder") and (not _number(batch.withdraw_remainder) or batch.withdraw_remainder > batch.amount):
                return "invalid batch.withdraw_remainder in " + id
    for field in ["batch_origins", "distribution", "production_remainders", "evolution_remainders", "planet_remainders", "blast_remainders", "destruction_remainders", "life_remainders", "civilization_remainders", "civilization_stats"]:
        if not _number_map(saved[field], false, false):
            return "invalid state." + field
    if not _number_map(saved.auto_resources, true) or not _number_map(saved.auto_star_deficits, false, false):
        return "invalid automatic production state"
    if not saved.resource_remainders is Dictionary or saved.resource_remainders.keys().size() != 2 or not saved.resource_remainders.has("basic") or not saved.resource_remainders.has("automatic"):
        return "invalid state.resource_remainders"
    for channel in ["basic", "automatic"]:
        if not _number_map(saved.resource_remainders[channel], false, false):
            return "invalid state.resource_remainders." + channel
    if not saved.ethics is Dictionary or not saved.civilization_homes is Dictionary:
        return "invalid civilization state"
    for id in saved.ethics:
        if id not in stages or not _number_map(saved.ethics[id], true):
            return "invalid state.ethics." + str(id)
        for ethic in saved.ethics[id]:
            if ethic not in ["m", "l", "w", "d", "c", "b"]:
                return "invalid ethic " + str(ethic)
    for id in saved.civilization_homes:
        if not _number_map(saved.civilization_homes[id], true):
            return "invalid civilization homes"
    return ""


#endregion


#region Settings
func save_settings():
    var config = ConfigFile.new()
    
    for item in Global.Settings:
        config.set_value(SETTING_SECTION, item, Global.Settings[item])
    config.save(SAVE_PATH)

func load_settings():
    var config = ConfigFile.new()
    var err = config.load(SAVE_PATH)
    if err != OK:
        return false
    for item in Global.Settings:
        Global.Settings[item] = config.get_value(SETTING_SECTION, item, Global.Settings[item])
    return true
#endregion