extends Node
class_name VersionChecker

const Config = preload("config.gd")
## Handles checking for game updates from the version manifest

signal version_check_started
signal version_check_completed(has_update: bool, latest_version: String, changelog: Array)
signal version_check_failed(error: String)

var http_request: HTTPRequest
var current_version: String = "0.0.0"
var latest_version: String = "0.0.0"
var manifest_data: Dictionary = {}

func _ready() -> void:
	http_request = HTTPRequest.new()
	add_child(http_request)
	http_request.request_completed.connect(_on_request_completed)
	
	# Load current local version
	_load_local_version()

func _load_local_version() -> void:
	if FileAccess.file_exists(Config.LOCAL_VERSION_FILE):
		var file := FileAccess.open(Config.LOCAL_VERSION_FILE, FileAccess.READ)
		if file:
			current_version = file.get_as_text().strip_edges()
			file.close()
			print("[VersionChecker] Local version: ", current_version)
	else:
		current_version = "0.0.0"
		print("[VersionChecker] No local version found, assuming fresh install")

func check_for_updates() -> void:
	emit_signal("version_check_started")
	print("[VersionChecker] Checking for updates at: ", Config.VERSION_MANIFEST_URL)
	
	var error := http_request.request(Config.VERSION_MANIFEST_URL)
	if error != OK:
		emit_signal("version_check_failed", "Failed to initiate version check request")

func _on_request_completed(result: int, response_code: int, _headers: PackedStringArray, body: PackedByteArray) -> void:
	if result != HTTPRequest.RESULT_SUCCESS:
		emit_signal("version_check_failed", "Network error: " + str(result))
		return
	
	if response_code != 200:
		emit_signal("version_check_failed", "Server returned error: " + str(response_code))
		return
	
	var json := JSON.new()
	var parse_result := json.parse(body.get_string_from_utf8())
	if parse_result != OK:
		emit_signal("version_check_failed", "Failed to parse version manifest")
		return
	
	manifest_data = json.data
	latest_version = manifest_data.get("latest_version", "0.0.0")
	
	var has_update := _compare_versions(current_version, latest_version) < 0
	var changelog: Array = _get_changelog_since(current_version)
	
	print("[VersionChecker] Latest version: ", latest_version, " | Has update: ", has_update)
	emit_signal("version_check_completed", has_update, latest_version, changelog)

func _compare_versions(v1: String, v2: String) -> int:
	## Returns -1 if v1 < v2, 0 if equal, 1 if v1 > v2
	var parts1 := v1.split(".")
	var parts2 := v2.split(".")
	
	for i in range(max(parts1.size(), parts2.size())):
		var p1 := int(parts1[i]) if i < parts1.size() else 0
		var p2 := int(parts2[i]) if i < parts2.size() else 0
		
		if p1 < p2:
			return -1
		elif p1 > p2:
			return 1
	
	return 0

func _get_changelog_since(since_version: String) -> Array:
	## Get all changelog entries since the given version
	var changelog: Array = []
	var releases: Array = manifest_data.get("releases", [])
	
	for release in releases:
		var release_version: String = release.get("version", "")
		if _compare_versions(since_version, release_version) < 0:
			changelog.append({
				"version": release_version,
				"date": release.get("date", ""),
				"changes": release.get("changelog", [])
			})
	
	return changelog

func get_download_info() -> Dictionary:
	## Returns info needed to download the latest version (platform-specific)
	var platform := Config.get_platform_name() # "windows", "linux", or "macos"
	var releases: Array = manifest_data.get("releases", [])
	
	for release in releases:
		if release.get("version") == latest_version:
			# Try platform-specific URL first, fall back to generic pck_url
			var pck_url: String = ""
			var pck_size: int = 0
			var checksum_md5: String = ""
			var checksum_sha256: String = ""
			
			# Check for platform-specific fields
			var platform_key := "pck_" + platform # e.g., "pck_windows", "pck_linux", "pck_macos"
			if release.has(platform_key):
				var platform_data: Dictionary = release.get(platform_key, {})
				pck_url = platform_data.get("url", "")
				pck_size = platform_data.get("size", 0)
				checksum_md5 = platform_data.get("checksum_md5", "")
				checksum_sha256 = platform_data.get("checksum_sha256", "")
			else:
				# Fall back to generic fields (single PCK for all platforms)
				pck_url = release.get("pck_url", "")
				pck_size = release.get("pck_size", 0)
				checksum_md5 = release.get("checksum_md5", "")
				checksum_sha256 = release.get("checksum_sha256", "")
			
			return {
				"url": pck_url,
				"size": pck_size,
				"checksum_md5": checksum_md5,
				"checksum_sha256": checksum_sha256
			}
	return {}

func save_version(version: String) -> void:
	## Save the current version to the local version file
	var file := FileAccess.open(Config.LOCAL_VERSION_FILE, FileAccess.WRITE)
	if file:
		file.store_string(version)
		file.close()
		current_version = version
		print("[VersionChecker] Saved version: ", version)