"""
一次性脚本：从 PostgreSQL 导出静态底图为 GeoPackage 文件。
运行一次即可，之后服务直接读本地 GPKG。

用法: python -m app.script.export_static_layers
"""
import os
import sys
import time

# 确保项目根目录在 sys.path 中
project_root = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
if project_root not in sys.path:
    sys.path.insert(0, project_root)

import geopandas as gpd
from sqlalchemy import create_engine
from config import settings

# GPKG 输出目录（相对于项目根目录）
GPKG_DIR = os.path.join(project_root, getattr(settings, "QGIS_GPKG_DIR", "app/data/gpkg"))

# 静态图层定义: {显示名: (schema.table, geom_column, srid)}
STATIC_LAYERS = {
    "水库":               ("qgis.rivers",                  "Geometry", 0),
    "市州驻地":           ("qgis.sx_capital",              "geometry", 0),
    "河流":               ("qgis.river",                   "Geometry", 0),
    "active_fault":       ("qgis.active_fault",            "Geometry", 0),
    "陕西省":             ("qgis.sx",                      "Geometry", 0),
    "乡镇驻地":           ("qgis.sx_street",               "dgeom",    0),
    "区县驻地":           ("qgis.sx_xa_county",            "Geometry", 0),
    "县界":               ("qgis.sx_xa_county_boundary",   "Geometry", 0),
    "周边区县":           ("qgis.sx_zb_county_boundary",   "Geometry", 0),
    "周边市州":           ("qgis.sx_zb_city",              "Geometry", 4326),
    "周边县区":           ("qgis.sx_zb_county",            "Geometry", 0),
    "traffic_expressway": ("qgis.traffic_expressway",      "Geometry", 0),
    "traffic_provincial": ("qgis.traffic_provincial",      "Geometry", 0),
    "traffic_railway":    ("qgis.traffic_railway",         "Geometry", 0),
    "traffic_township":   ("qgis.traffic_township",        "Geometry", 0),
    "traffic_trunk_line": ("qgis.traffic_trunk_line",      "Geometry", 0),
}


def export_layers():
    os.makedirs(GPKG_DIR, exist_ok=True)

    conn_str = (
        f"postgresql://{settings.DB_USER}:{settings.DB_PASSWORD}"
        f"@{settings.DB_HOST}:{settings.DB_PORT}/{settings.DB_NAME}"
    )
    engine = create_engine(conn_str)

    for layer_name, (table_ref, geom_col, srid) in STATIC_LAYERS.items():
        t0 = time.time()
        schema, table = table_ref.split(".", 1)
        print(f"导出 {layer_name} ({table_ref}) ...", end=" ", flush=True)

        try:
            sql = f'SELECT * FROM "{schema}"."{table}"'
            gdf = gpd.read_postgis(sql, engine, geom_col=geom_col)

            if srid and srid > 0:
                gdf = gdf.set_crs(epsg=srid, allow_override=True)
            elif gdf.crs is None:
                gdf = gdf.set_crs(epsg=4326)

            gpkg_path = os.path.join(GPKG_DIR, f"{table}.gpkg")
            gdf.to_file(gpkg_path, driver="GPKG")

            print(f"✓ {len(gdf)} 行, {time.time() - t0:.1f}s")

        except Exception as e:
            print(f"✗ 失败: {e}")

    engine.dispose()
    print(f"\n导出完成！文件目录: {GPKG_DIR}")


if __name__ == "__main__":
    export_layers()