#!/usr/bin/env bash

set -euo pipefail

SOURCE_ROOT="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
VERSION="${PTLINUX_VERSION:-0.5.8}"
if [[ ! "$VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]
then
	printf 'Invalid launcher version: %s (expected X.Y.Z)\n' "$VERSION" >&2
	exit 2
fi
DATA_HOME="${XDG_DATA_HOME:-${HOME}/.local/share}"
BIN_HOME="${HOME}/.local/bin"
APPLICATION_HOME="${DATA_HOME}/applications"
PIXMAP_HOME="${DATA_HOME}/pixmaps"
ICON_PATH="${PIXMAP_HOME}/eu.pristontale.PTLinux.png"
DEFAULT_INSTALL_DIRECTORY="${HOME}/Games/PristontaleEU"
LEGACY_INSTALL_DIRECTORY="${DATA_HOME}/pristontale-eu"
INSTALL_DIRECTORY_EXPLICIT=0
if [[ -n "${PTLINUX_INSTALL_DIR:-}" ]]
then
	INSTALL_DIRECTORY="$PTLINUX_INSTALL_DIR"
	INSTALL_DIRECTORY_EXPLICIT=1
else
	INSTALL_DIRECTORY="$DEFAULT_INSTALL_DIRECTORY"
fi
PRESERVED_LEGACY_INSTALL=0
PYTHON_BIN="${PTLINUX_PYTHON:-python3}"
DRY_RUN=0
RUN_DOCTOR=1
INSTALL_DEPENDENCIES=1

usage()
{
	printf '%s\n' \
		"Usage: ./install.sh [--install-dir PATH] [--dry-run] [--skip-deps] [--skip-doctor]" \
		"" \
		"  --install-dir PATH  Store the app, managed game, and runtime data at PATH." \
		"                      Default: ~/Games/PristontaleEU"
}

while (( $# > 0 ))
do
	case "$1" in
		--install-dir)
			if (( $# < 2 ))
			then
				printf '%s\n' "--install-dir requires a path." >&2
				exit 2
			fi
			INSTALL_DIRECTORY="$2"
			INSTALL_DIRECTORY_EXPLICIT=1
			shift 2
			;;
		--install-dir=*)
			INSTALL_DIRECTORY="${1#*=}"
			INSTALL_DIRECTORY_EXPLICIT=1
			shift
			;;
		--dry-run)
			DRY_RUN=1
			shift
			;;
		--skip-doctor)
			RUN_DOCTOR=0
			shift
			;;
		--skip-deps)
			INSTALL_DEPENDENCIES=0
			shift
			;;
		-h|--help)
			usage
			exit 0
			;;
		*)
			printf 'Unknown option: %s\n' "$1" >&2
			usage >&2
			exit 2
			;;
	esac
done

if (( INSTALL_DIRECTORY_EXPLICIT == 0 )) \
	&& [[ ! -d "${DEFAULT_INSTALL_DIRECTORY}/app/ptlinux" \
		&& ! -d "${DEFAULT_INSTALL_DIRECTORY}/app/current/ptlinux" ]] \
	&& [[ -d "${LEGACY_INSTALL_DIRECTORY}/app/ptlinux" \
		|| -d "${LEGACY_INSTALL_DIRECTORY}/app/current/ptlinux" \
		|| -f "${LEGACY_INSTALL_DIRECTORY}/launcher-prefix/drive_c/Program Files (x86)/Pristontale EU/Game.exe" ]]
then
	INSTALL_DIRECTORY="$LEGACY_INSTALL_DIRECTORY"
	PRESERVED_LEGACY_INSTALL=1
fi

if [[ -z "$INSTALL_DIRECTORY" \
	|| "$INSTALL_DIRECTORY" == *$'\n'* \
	|| "$INSTALL_DIRECTORY" == *$'\r'* ]]
then
	printf '%s\n' "Install directory is empty or contains invalid characters." >&2
	exit 2
fi

case "$INSTALL_DIRECTORY" in
	"~")
		INSTALL_DIRECTORY="$HOME"
		;;
	"~/"*)
		INSTALL_DIRECTORY="${HOME}/${INSTALL_DIRECTORY:2}"
		;;
	"~"*)
		printf '%s\n' "Use an absolute path instead of another user's ~ directory." >&2
		exit 2
		;;
esac

if [[ "$INSTALL_DIRECTORY" != /* ]]
then
	INSTALL_DIRECTORY="${PWD}/${INSTALL_DIRECTORY}"
fi
if command -v realpath >/dev/null 2>&1
then
	INSTALL_DIRECTORY="$(realpath -m -- "$INSTALL_DIRECTORY")"
fi
if [[ "$INSTALL_DIRECTORY" == "/" ]]
then
	printf '%s\n' "Refusing to use the filesystem root as the install directory." >&2
	exit 2
fi
APP_ROOT="${INSTALL_DIRECTORY}/app"
RELEASES_ROOT="${APP_ROOT}/releases"
RELEASE_ROOT="${RELEASES_ROOT}/${VERSION}"

if [[ ! -d "${SOURCE_ROOT}/ptlinux" \
	|| ! -f "${SOURCE_ROOT}/ptdiag/assbin.py" \
	|| ! -f "${SOURCE_ROOT}/ptdiag/__init__.py" \
	|| ! -f "${SOURCE_ROOT}/ptdiag/logs.py" \
	|| ! -f "${SOURCE_ROOT}/ptlinux/desktop_entry.py" \
	|| ! -f "${SOURCE_ROOT}/ptlinux/launcher_wrapper.py" \
	|| ! -f "${SOURCE_ROOT}/ptlinux/self_update.py" \
	|| ! -f "${SOURCE_ROOT}/ptlinux/launcher-update-public.pem" \
	|| ! -f "${SOURCE_ROOT}/packaging/eu.pristontale.PTLinux.desktop" \
	|| ! -f "${SOURCE_ROOT}/packaging/eu.pristontale.PTLinux.png" \
	|| ! -f "${SOURCE_ROOT}/packaging/pristontale-eu" \
	|| ! -f "${SOURCE_ROOT}/packaging/install-dependencies.sh" ]]
then
	printf '%s\n' "Installer source is incomplete." >&2
	exit 1
fi

printf '%s\n' "Installing PristonTale EU Linux launcher for the current user"
if (( PRESERVED_LEGACY_INSTALL == 1 ))
then
	printf '%s\n' "  Existing installation found; preserving its previous data location."
fi
printf '  Install data: %s\n' "$INSTALL_DIRECTORY"
printf '  Application:  %s\n' "$APP_ROOT"
printf '  Command:      %s\n' "${BIN_HOME}/pristontale-eu"
printf '  Desktop:      %s\n' "${APPLICATION_HOME}/eu.pristontale.PTLinux.desktop"

if (( INSTALL_DEPENDENCIES == 1 ))
then
	# shellcheck source=packaging/install-dependencies.sh
	source "${SOURCE_ROOT}/packaging/install-dependencies.sh"
	ptlinux_install_host_dependencies "$DRY_RUN"
else
	printf '%s\n' "Skipping host dependency installation."
fi

if (( DRY_RUN == 1 ))
then
	exit 0
fi

if ! command -v "$PYTHON_BIN" >/dev/null 2>&1
then
	printf 'Python was not found after dependency installation: %s\n' "$PYTHON_BIN" >&2
	exit 1
fi

if ! "$PYTHON_BIN" -c 'import sys; raise SystemExit(0 if sys.version_info >= (3, 11) else 1)'
then
	printf '%s\n' "Python 3.11 or newer is required." >&2
	exit 1
fi

install -d -m 0755 "$APP_ROOT" "$RELEASES_ROOT" "$BIN_HOME" "$APPLICATION_HOME" "$PIXMAP_HOME"
STAGING_RELEASE="${RELEASES_ROOT}/.${VERSION}.$$.staging"
if [[ -e "$STAGING_RELEASE" || -L "$STAGING_RELEASE" ]]
then
	printf 'Launcher staging path already exists: %s\n' "$STAGING_RELEASE" >&2
	exit 1
fi
install -d -m 0755 "$STAGING_RELEASE"
install -d -m 0755 "${STAGING_RELEASE}/ptlinux" "${STAGING_RELEASE}/ptdiag"
install -m 0644 "${SOURCE_ROOT}/ptlinux/"*.py "${STAGING_RELEASE}/ptlinux/"
install -m 0644 \
	"${SOURCE_ROOT}/ptlinux/launcher-update-public.pem" \
	"${STAGING_RELEASE}/ptlinux/launcher-update-public.pem"
install -m 0644 "${SOURCE_ROOT}/ptdiag/__init__.py" "${STAGING_RELEASE}/ptdiag/__init__.py"
install -m 0644 "${SOURCE_ROOT}/ptdiag/assbin.py" "${STAGING_RELEASE}/ptdiag/assbin.py"
install -m 0644 "${SOURCE_ROOT}/ptdiag/logs.py" "${STAGING_RELEASE}/ptdiag/logs.py"
printf '{\n  "schema": 1,\n  "version": "%s"\n}\n' "$VERSION" > "${STAGING_RELEASE}/release.json"
chmod 0644 "${STAGING_RELEASE}/release.json"

if ! "$PYTHON_BIN" -I -c \
	'import sys; sys.path.insert(0, sys.argv[1]); import ptlinux, ptlinux.cli, ptlinux.self_update; raise SystemExit(0 if ptlinux.__version__ == sys.argv[2] else 1)' \
	"$STAGING_RELEASE" "$VERSION"
then
	printf '%s\n' "The staged launcher failed its import/version check." >&2
	rm -r -- "$STAGING_RELEASE"
	exit 1
fi

REPLACED_RELEASE=""
if [[ -e "$RELEASE_ROOT" || -L "$RELEASE_ROOT" ]]
then
	if [[ ! -d "$RELEASE_ROOT" || -L "$RELEASE_ROOT" ]]
	then
		printf 'Existing launcher release is not a directory: %s\n' "$RELEASE_ROOT" >&2
		rm -r -- "$STAGING_RELEASE"
		exit 1
	fi
	REPLACED_RELEASE="${RELEASES_ROOT}/.${VERSION}.$$.replaced"
	mv -- "$RELEASE_ROOT" "$REPLACED_RELEASE"
fi
if ! mv -- "$STAGING_RELEASE" "$RELEASE_ROOT"
then
	if [[ -n "$REPLACED_RELEASE" && -d "$REPLACED_RELEASE" ]]
	then
		mv -- "$REPLACED_RELEASE" "$RELEASE_ROOT"
	fi
	exit 1
fi
if [[ -n "$REPLACED_RELEASE" && -d "$REPLACED_RELEASE" ]]
then
	rm -r -- "$REPLACED_RELEASE"
fi

CURRENT_TARGET=""
if [[ -L "${APP_ROOT}/current" ]]
then
	CURRENT_TARGET="$(readlink -- "${APP_ROOT}/current")"
	if [[ ! "$CURRENT_TARGET" =~ ^releases/[0-9]+\.[0-9]+\.[0-9]+$ ]]
	then
		printf 'Existing launcher current link is unsafe: %s\n' "$CURRENT_TARGET" >&2
		exit 1
	fi
	if [[ ! -d "${APP_ROOT}/${CURRENT_TARGET}" ]]
	then
		printf 'Existing launcher current link is broken: %s\n' "$CURRENT_TARGET" >&2
		exit 1
	fi
elif [[ -e "${APP_ROOT}/current" ]]
then
	printf 'Launcher current path is not a symbolic link: %s\n' "${APP_ROOT}/current" >&2
	exit 1
fi
if [[ -L "${APP_ROOT}/previous" ]]
then
	PREVIOUS_TARGET="$(readlink -- "${APP_ROOT}/previous")"
	if [[ ! "$PREVIOUS_TARGET" =~ ^releases/[0-9]+\.[0-9]+\.[0-9]+$ \
		|| ! -d "${APP_ROOT}/${PREVIOUS_TARGET}" ]]
	then
		printf 'Existing launcher previous link is unsafe or broken: %s\n' "$PREVIOUS_TARGET" >&2
		exit 1
	fi
elif [[ -e "${APP_ROOT}/previous" ]]
then
	printf 'Launcher previous path is not a symbolic link: %s\n' "${APP_ROOT}/previous" >&2
	exit 1
fi
if [[ -n "$CURRENT_TARGET" && "$CURRENT_TARGET" != "releases/${VERSION}" ]]
then
	PREVIOUS_LINK="${APP_ROOT}/.previous.$$.tmp"
	ln -s -- "$CURRENT_TARGET" "$PREVIOUS_LINK"
	mv -Tf -- "$PREVIOUS_LINK" "${APP_ROOT}/previous"
fi
CURRENT_LINK="${APP_ROOT}/.current.$$.tmp"
ln -s -- "releases/${VERSION}" "$CURRENT_LINK"
mv -Tf -- "$CURRENT_LINK" "${APP_ROOT}/current"

"$PYTHON_BIN" "${RELEASE_ROOT}/ptlinux/launcher_wrapper.py" \
	"${SOURCE_ROOT}/packaging/pristontale-eu" \
	"$APP_ROOT" \
	"$INSTALL_DIRECTORY" \
	"${BIN_HOME}/pristontale-eu"
install -m 0644 \
	"${SOURCE_ROOT}/packaging/eu.pristontale.PTLinux.png" \
	"$ICON_PATH"
"$PYTHON_BIN" "${RELEASE_ROOT}/ptlinux/desktop_entry.py" \
	"${SOURCE_ROOT}/packaging/eu.pristontale.PTLinux.desktop" \
	"${BIN_HOME}/pristontale-eu" \
	"$ICON_PATH" \
	"${APPLICATION_HOME}/eu.pristontale.PTLinux.desktop"

if command -v desktop-file-validate >/dev/null 2>&1
then
	desktop-file-validate "${APPLICATION_HOME}/eu.pristontale.PTLinux.desktop"
fi

if command -v update-desktop-database >/dev/null 2>&1
then
	update-desktop-database "$APPLICATION_HOME" >/dev/null 2>&1 || true
fi

printf '%s\n' "Launcher files installed."
DOCTOR_READY=1
if (( RUN_DOCTOR == 1 ))
then
	if ! "${BIN_HOME}/pristontale-eu" doctor
	then
		DOCTOR_READY=0
	fi
else
	printf '%s\n' "Host readiness check skipped."
fi

printf '%s\n' "Start PristonTale EU with:"
printf '  %q gui\n' "${BIN_HOME}/pristontale-eu"
case ":${PATH:-}:" in
	*":${BIN_HOME}:"*)
		;;
	*)
		printf '%s\n' \
			"Note: ${BIN_HOME} is not in PATH for this shell." \
			"The application-menu shortcut already uses the full path."
		if [[ "${SHELL##*/}" == "fish" ]]
		then
			printf '%s\n' "Enable the short command in Fish with:"
			printf '  fish_add_path %q\n' "$BIN_HOME"
		else
			printf '%s\n' "Enable the short command in this Bash/Zsh session with:"
			printf '  export PATH=%q:"$PATH"\n' "$BIN_HOME"
		fi
		;;
esac

if (( DOCTOR_READY == 0 ))
then
	printf '%s\n' \
		"Launcher files were installed, but this host is not ready to run the game." \
		"Resolve the diagnostics above, then run the launcher command again." >&2
	exit 1
fi

printf '%s\n' "Installation ready."