"""GIS parser — Shapefile, GeoJSON, KML via geopandas."""

import os
import json

import geopandas as gpd


def parse_gis(file_path: str) -> dict:
    ext = os.path.splitext(file_path)[1].lower()

    try:
        if ext == ".geojson" or ext == ".json":
            gdf = gpd.read_file(file_path, driver="GeoJSON")
        elif ext == ".shp":
            gdf = gpd.read_file(file_path)
        elif ext == ".kml":
            gpd.io.file.fiona.drvsupport.supported_drivers["KML"] = "r"
            gdf = gpd.read_file(file_path, driver="KML")
        elif ext == ".gpkg":
            gdf = gpd.read_file(file_path)
        else:
            return {"markdown": "", "error": f"不支持的 GIS 格式: {ext}"}
    except Exception as e:
        return {"markdown": "", "error": f"GIS 文件解析失败: {e}"}

    parts = ["## GIS 数据解析结果\n"]
    parts.append(f"**文件**: {os.path.basename(file_path)}")
    parts.append(f"**要素数量**: {len(gdf)}")
    parts.append(f"**坐标系**: {gdf.crs or '未定义'}\n")

    # Geometry types
    geom_types = gdf.geometry.geom_type.value_counts()
    if not geom_types.empty:
        parts.append("### 几何类型\n\n| 类型 | 数量 |\n| --- | --- |")
        for gt, cnt in geom_types.items():
            parts.append(f"| {gt} | {cnt} |")
        parts.append("")

    # Bounds
    bounds = gdf.total_bounds  # [minx, miny, maxx, maxy]
    parts.append(f"### 范围\n\n- 最小经度: {bounds[0]:.6f}\n- 最小纬度: {bounds[1]:.6f}\n- 最大经度: {bounds[2]:.6f}\n- 最大纬度: {bounds[3]:.6f}\n")

    # Attributes
    non_geom_cols = [c for c in gdf.columns if c != "geometry"]
    if non_geom_cols:
        parts.append("### 属性字段\n\n| 字段名 | 类型 | 示例值 |\n| --- | --- | --- |")
        for col in non_geom_cols:
            dtype = str(gdf[col].dtype)
            sample = str(gdf[col].iloc[0]) if len(gdf) > 0 else ""
            if len(sample) > 80:
                sample = sample[:80] + "..."
            parts.append(f"| {col} | {dtype} | {sample} |")
        parts.append("")

    # First N features as table
    n_preview = min(20, len(gdf))
    if n_preview > 0 and non_geom_cols:
        parts.append(f"### 前 {n_preview} 条要素属性\n")
        header = "| " + " | ".join(non_geom_cols) + " |"
        sep = "| " + " | ".join("---" for _ in non_geom_cols) + " |"
        parts.append(header)
        parts.append(sep)
        for _, row in gdf.head(n_preview).iterrows():
            vals = []
            for c in non_geom_cols:
                v = str(row[c]) if row[c] is not None else ""
                if len(v) > 60:
                    v = v[:60] + "..."
                vals.append(v)
            parts.append("| " + " | ".join(vals) + " |")
        if len(gdf) > n_preview:
            parts.append(f"\n> 共 {len(gdf)} 条要素，仅显示前 {n_preview} 条。")
        parts.append("")

    return {"markdown": "\n".join(parts)}