#!/bin/bash
set -eu

PACKAGE_ROOT=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
APP_ROOT="${TRIM_APPDEST:-$PACKAGE_ROOT/app}"
DATA_ROOT="${TRIM_PKGVAR:-$PACKAGE_ROOT/var}"
VERSION_FILE="$APP_ROOT/runtime/VERSION"
WHEEL_ROOT="$APP_ROOT/runtime/wheels"
CORE_REQUIREMENTS="$APP_ROOT/runtime/runtime-core.txt"
RUNTIME_ROOT="$DATA_ROOT/runtime"

fail() {
    printf '%s\n' "$1" >&2
    exit 1
}

[ -f "$VERSION_FILE" ] || fail "ImageFind 运行环境初始化失败：安装包缺少版本信息。"
[ -d "$WHEEL_ROOT" ] || fail "ImageFind 运行环境初始化失败：安装包缺少核心 wheelhouse。"
[ -f "$CORE_REQUIREMENTS" ] || fail "ImageFind 运行环境初始化失败：安装包缺少核心依赖锁文件。"

VERSION=$(sed -n '1p' "$VERSION_FILE")
case "$VERSION" in
    ''|*[!0-9.]* ) fail "ImageFind 运行环境初始化失败：版本信息无效。" ;;
esac
PACKAGE_ID=$(sed -n '2p' "$VERSION_FILE")
case "$PACKAGE_ID" in
    ''|*[!0-9a-f]* ) fail "ImageFind 运行环境初始化失败：安装包指纹无效。" ;;
esac
[ "${#PACKAGE_ID}" -eq 64 ] || fail "ImageFind 运行环境初始化失败：安装包指纹长度无效。"

if [ -n "${IMAGEFIND_PYTHON_PATH:-}" ]; then
    SYSTEM_PYTHON="$IMAGEFIND_PYTHON_PATH"
else
    SYSTEM_PYTHON="/var/apps/python312/target/bin/python3"
fi
[ -x "$SYSTEM_PYTHON" ] || fail "ImageFind 需要 fnOS Python 3.12 依赖，请先确认 python312 已安装。"
PYTHON_VERSION=$($SYSTEM_PYTHON -c 'import sys; print(f"{sys.version_info.major}.{sys.version_info.minor}")' 2>/dev/null) \
    || fail "ImageFind 无法运行 fnOS Python 3.12。"
[ "$PYTHON_VERSION" = "3.12" ] || fail "ImageFind 需要 Python 3.12，当前为 $PYTHON_VERSION。"

mkdir -p "$RUNTIME_ROOT"
TARGET="$RUNTIME_ROOT/core-$VERSION"
STAGE="$RUNTIME_ROOT/.core-$VERSION.tmp.$$"
CURRENT="$RUNTIME_ROOT/current"

runtime_valid() {
    [ -x "$1/bin/python" ] || return 1
    [ -f "$1/.imagefind-package-id" ] || return 1
    [ "$(sed -n '1p' "$1/.imagefind-package-id")" = "$PACKAGE_ID" ] || return 1
    RUNTIME_VERSION=$(
        IMAGEFIND_DATA_DIR="$DATA_ROOT/data" "$1/bin/python" -c \
            'import imagefind; print(imagefind.__version__)' 2>"$RUNTIME_ROOT/version-check.err"
    ) || return 1
    [ "$RUNTIME_VERSION" = "$VERSION" ]
}

if ! runtime_valid "$TARGET"; then
    rm -rf "$STAGE"
    "$SYSTEM_PYTHON" -m venv "$STAGE" \
        || { rm -rf "$STAGE"; fail "ImageFind 无法创建 Python 3.12 核心运行环境。"; }
    APP_WHEEL=""
    for candidate in "$APP_ROOT"/runtime/imagefind-*.whl; do
        if [ -f "$candidate" ]; then
            APP_WHEEL="$candidate"
            break
        fi
    done
    [ -n "$APP_WHEEL" ] \
        || { rm -rf "$STAGE"; fail "ImageFind 运行环境初始化失败：安装包缺少应用 wheel。"; }
    if ! "$STAGE/bin/python" -m pip install \
        --disable-pip-version-check --no-input --no-index \
        --find-links "$WHEEL_ROOT" --requirement "$CORE_REQUIREMENTS" "$APP_WHEEL"; then
        rm -rf "$STAGE"
        fail "ImageFind 核心运行环境离线安装失败，请重新安装应用。"
    fi
    printf '%s\n' "$PACKAGE_ID" >"$STAGE/.imagefind-package-id"
    runtime_valid "$STAGE" \
        || {
            if [ -s "$RUNTIME_ROOT/version-check.err" ]; then
                cat "$RUNTIME_ROOT/version-check.err" >&2 || true
            fi
            rm -rf "$STAGE"
            fail "ImageFind 核心运行环境校验失败。"
        }
    if [ -e "$TARGET" ]; then
        BACKUP="$RUNTIME_ROOT/core-$VERSION.invalid.$(date +%s)"
        mv "$TARGET" "$BACKUP"
    fi
    mv "$STAGE" "$TARGET"
fi

LINK="$RUNTIME_ROOT/.current.$$"
rm -f "$LINK"
ln -s "$TARGET" "$LINK"
if [ -d "$CURRENT" ] && [ ! -L "$CURRENT" ]; then
    mv "$CURRENT" "$RUNTIME_ROOT/current.previous.$(date +%s)"
fi
# mv follows a destination symlink that points at a directory and would place
# LINK *inside* the old runtime.  Replace the directory entry itself so an
# upgrade atomically switches current even when it is a valid or dangling
# symlink left by an earlier release.
if ! "$SYSTEM_PYTHON" -c \
    'import os,sys; os.replace(sys.argv[1], sys.argv[2])' \
    "$LINK" "$CURRENT"; then
    rm -f "$LINK"
    fail "ImageFind 核心运行环境切换失败：无法原子更新 current。"
fi
if ! runtime_valid "$CURRENT"; then
    if [ -L "$CURRENT" ]; then
        CURRENT_LINK=$(readlink "$CURRENT" 2>/dev/null || printf '%s' '无法读取')
    elif [ -e "$CURRENT" ]; then
        CURRENT_LINK='不是符号链接'
    else
        CURRENT_LINK='不存在'
    fi
    if [ -x "$CURRENT/bin/python" ]; then
        ACTUAL_VERSION=$(
            IMAGEFIND_DATA_DIR="$DATA_ROOT/data" "$CURRENT/bin/python" -c \
                'import imagefind; print(imagefind.__version__)' 2>"$RUNTIME_ROOT/version-check.err" \
                || printf '%s' '无法读取'
        )
    else
        ACTUAL_VERSION='Python 不可执行'
    fi
    fail "ImageFind 核心运行环境切换失败：期望版本 $VERSION，current=$CURRENT_LINK，实际版本=$ACTUAL_VERSION。"
fi