"""JRXML 文件验证服务（FastAPI）。

使用 lxml XML Schema 验证作为 JasperReports 7.0.6 编译验证的第一阶段后备方案。
要进行完整的编译验证，需要基于 Java 的验证器以及 JasperReports 7.0.6 + JDK 21。

启动: uvicorn validation_service.main:app --port 8001
"""

import re
import xml.etree.ElementTree as ET
from pathlib import Path

from fastapi import FastAPI
from lxml import etree
from pydantic import BaseModel

app = FastAPI(title="JRXML 验证服务")

SCHEMA_DIR = Path(__file__).parent / "schemas"
SCHEMA_FILE = SCHEMA_DIR / "jasperreport_7_0_6.xsd"


class ValidationRequest(BaseModel):
    jrxml: str


class ValidationResponse(BaseModel):
    valid: bool
    error: str


def _check_structural_issues(jrxml: str) -> list[str]:
    """检查 JRXML 中常见的结构性问题。"""
    issues = []
    root = None

    try:
        root = ET.fromstring(jrxml)
    except ET.ParseError as e:
        issues.append(f"XML 解析错误：{e}")
        return issues

    # 同时处理带命名空间和不带命名空间的元素名
    ns = "http://jasperreports.sourceforge.net/jasperreports"

    declared_fields = set()
    for elem in root.iter():
        tag = elem.tag.split("}")[-1] if "}" in elem.tag else elem.tag
        if tag == "field":
            name = elem.get("name")
            if name:
                declared_fields.add(name)

    field_expr_pattern = re.compile(r'\$F\{(\w+)\}')
    for m in field_expr_pattern.finditer(jrxml):
        field_name = m.group(1)
        if field_name not in declared_fields:
            issues.append(
                f"字段 '{field_name}' 在表达式中使用但未在 <field> 部分声明"
            )

    query = None
    for elem in root.iter():
        tag = elem.tag.split("}")[-1] if "}" in elem.tag else elem.tag
        if tag == "queryString":
            query = elem
            break
    if query is not None:
        query_text = "".join(query.itertext()).strip()
        if not query_text:
            issues.append("<queryString> 为空 - 请在 CDATA 中添加 SQL 查询")
        elif not any(kw in query_text.upper() for kw in ["SELECT"]):
            issues.append("<queryString> 似乎不包含 SQL SELECT 查询")

    if not root.get("pageWidth"):
        issues.append("缺少 <jasperReport> 上的 pageWidth 属性")
    if not root.get("pageHeight"):
        issues.append("缺少 <jasperReport> 上的 pageHeight 属性")
    if not root.get("name"):
        issues.append("缺少 <jasperReport> 上的 'name' 属性")

    return issues


def _validate_xsd(jrxml: str) -> tuple[bool, str]:
    """根据 JasperReports XSD schema 验证 JRXML。"""
    if not SCHEMA_FILE.exists():
        return True, ""

    try:
        schema_doc = etree.parse(str(SCHEMA_FILE))
        xmlschema = etree.XMLSchema(schema_doc)
        doc = etree.fromstring(jrxml.encode("utf-8"))
        xmlschema.assertValid(doc)
        return True, ""
    except etree.DocumentInvalid as e:
        return False, str(e)
    except etree.XMLSchemaError as e:
        return False, f"Schema 错误：{e}"
    except Exception as e:
        return False, f"XML 验证错误：{e}"


@app.post("/validate", response_model=ValidationResponse)
async def validate_jrxml(req: ValidationRequest):
    jrxml = req.jrxml.strip()
    if not jrxml:
        return ValidationResponse(valid=False, error="JRXML 内容为空")

    structural_issues = _check_structural_issues(jrxml)
    if structural_issues:
        return ValidationResponse(valid=False, error="; ".join(structural_issues))

    valid, xsd_error = _validate_xsd(jrxml)
    if not valid:
        return ValidationResponse(valid=False, error=xsd_error)

    return ValidationResponse(valid=True, error="")


@app.get("/health")
async def health():
    schema_available = SCHEMA_FILE.exists()
    return {
        "status": "ok",
        "schema_available": schema_available,
        "validation_type": "XSD" if schema_available else "仅结构检查",
        "note": "如需完整的 JasperReports 7.0.6 编译验证，请使用基于 Java 的验证器",
    }