"""CAD parser — DXF via ezdxf, DWG via ODA File Converter."""
from __future__ import annotations

import os
import subprocess
import tempfile
import ezdxf


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

    if ext == ".dwg":
        dxf_path = _convert_dwg(file_path)
        if dxf_path is None:
            return {"markdown": "", "error": "DWG 需要 ODA File Converter，下载: https://www.opendesign.com/guestfiles/oda_file_converter"}
        file_path = dxf_path

    try:
        doc = ezdxf.readfile(file_path)
    except Exception as e:
        return {"markdown": "", "error": f"无法解析 DXF: {e}"}

    return _extract(doc)


def _convert_dwg(dwg_path: str) -> str | None:
    candidates = [
        "ODAFileConverter",
        "/usr/local/bin/ODAFileConverter",
        "/Applications/ODAFileConverter.app/Contents/MacOS/ODAFileConverter",
        r"C:\Program Files\ODA\ODAFileConverter\ODAFileConverter.exe",
    ]
    converter = None
    for c in candidates:
        if os.path.isfile(c) or _which(c):
            converter = c
            break
    if not converter:
        return None

    input_dir = os.path.dirname(os.path.abspath(dwg_path))
    output_dir = tempfile.mkdtemp(prefix="engimind_cad_")
    filename = os.path.basename(dwg_path)
    try:
        subprocess.run([converter, input_dir, output_dir, "ACAD2018", "DXF", "0", "1", filename],
                       check=True, timeout=60, capture_output=True)
    except Exception:
        return None

    base = os.path.splitext(filename)[0]
    dxf = os.path.join(output_dir, base + ".dxf")
    return dxf if os.path.isfile(dxf) else None


def _which(name: str) -> bool:
    try:
        return subprocess.run(["which", name], capture_output=True, timeout=5).returncode == 0
    except Exception:
        return False


def _extract(doc: ezdxf.document.Drawing) -> dict:
    parts = ["## CAD 图纸解析结果\n"]

    # Layers
    layers = [{"name": l.dxf.name, "color": l.dxf.color} for l in doc.layers]
    if layers:
        parts.append("### 图层列表\n\n| 图层名 | 颜色编号 |\n| --- | --- |")
        for l in layers:
            parts.append(f"| {l['name']} | {l['color']} |")
        parts.append("")

    msp = doc.modelspace()
    entity_count = {}
    texts, dimensions, blocks = [], [], set()

    for e in msp:
        et = e.dxftype()
        entity_count[et] = entity_count.get(et, 0) + 1
        if et == "TEXT":
            texts.append(e.dxf.text)
        elif et == "MTEXT":
            texts.append(e.text)
        elif et == "DIMENSION":
            try:
                dimensions.append(e.dxf.text or "测量值")
            except Exception:
                pass
        elif et == "INSERT":
            blocks.add(e.dxf.name)

    if entity_count:
        parts.append("### 实体统计\n\n| 实体类型 | 数量 |\n| --- | --- |")
        for et, cnt in sorted(entity_count.items()):
            parts.append(f"| {et} | {cnt} |")
        parts.append("")

    if texts:
        parts.append("### 文字标注\n")
        for t in texts[:200]:
            clean = t.strip().replace("\n", " ")
            if clean:
                parts.append(f"- {clean}")
        if len(texts) > 200:
            parts.append(f"\n> 共 {len(texts)} 条，仅显示前 200 条。")
        parts.append("")

    if dimensions:
        parts.append("### 尺寸标注\n")
        for d in dimensions[:100]:
            parts.append(f"- {d}")
        parts.append("")

    if blocks:
        parts.append("### 使用的图块\n")
        for b in sorted(blocks):
            parts.append(f"- {b}")
        parts.append("")

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