from __future__ import annotations

from pathlib import Path

from genesis.data_models import StructuredSource
from genesis.impact.code_parser import CodeParser
from genesis.impact.existing_system_explorer import ExistingSystemExplorer
from genesis.parsers.excel_parser import ExcelParser
from genesis.parsers.rule_doc_parser import RuleDocParser
from genesis.parsers.word_template_parser import WordTemplateParser

XLSX_EXTS = (".xlsx", ".xls")
DOCX_EXT = ".docx"


def _validate_path(path: str | Path, allowed_exts: tuple[str, ...]) -> Path:
    """校验文件扩展名合法且文件存在（T7 DRY：消除三处重复校验）。

    Raises:
        ValueError: 扩展名不在 allowed_exts（含无扩展名）
        FileNotFoundError: 文件不存在
    """
    p = Path(path)
    if p.suffix.lower() not in allowed_exts:
        raise ValueError(f"不支持的文件类型: {p.suffix or '(无扩展名)'}")
    if not p.exists():
        raise FileNotFoundError(str(path))
    return p


class SourceParser:
    """全量输入门面：Excel 要件定义 + Word 模板 + Word 规则 → StructuredSource。

    角色由调用方按 api-design file_type 语义显式传入（requirements/template/
    write_instruction/rules），不做基于文件名的隐式猜测（spec §3.4）。
    """

    def __init__(self) -> None:
        self._excel = ExcelParser()

    def parse(
        self,
        requirement_paths: list[str | Path] | None = None,
        template_path: str | Path | None = None,
        write_instruction_paths: list[str | Path] | None = None,
        rule_paths: list[str | Path] | None = None,
        existing_system_path: str | Path | None = None,
        existing_system_language: str | None = None,
        design_doc_paths: list[str | Path] | None = None,
    ) -> StructuredSource:
        """扩展名校验先于存在性校验（不存在的文件若扩展名未知将抛出 ValueError 而非 FileNotFoundError）。

        existing_system_path：既有系统源码目录（追加/改修场景）。提供时解析为
        ExistingSystemInfo（门控通过 → 进入影响调查）；未提供/解析失败 → 保持 None。
        existing_system_language：既有系统源码开发语言（如 "java"）。默认 None 表示
        由 CodeParser 按扩展名自动探测；显式指定时按该语言解析（多语言支持扩展点）。
        """

        requirement_paths = requirement_paths or []
        write_instruction_paths = write_instruction_paths or []
        rule_paths = rule_paths or []

        tables = []
        comments = []
        for p in requirement_paths:
            path = _validate_path(p, XLSX_EXTS)
            result = self._excel.parse(path)
            tables.extend(result.tables)
            comments.extend(result.comments)

        template = None
        if template_path is not None:
            tpath = _validate_path(template_path, (DOCX_EXT,))
            template = WordTemplateParser().parse(tpath)

        rule_docs = []
        for p in [*write_instruction_paths, *rule_paths]:
            path = _validate_path(p, (DOCX_EXT,))
            # 做成说明书与记入规则均为 Type A 写入规则 → write（api-design §2.2）
            rule_docs.append(RuleDocParser().parse(path, category="write"))

        existing_system = None
        if existing_system_path is not None:
            code = CodeParser().parse(existing_system_path, language=existing_system_language)
            existing_system = ExistingSystemExplorer().explore(code)

        design_docs = []
        for p in (design_doc_paths or []):
            dpath = _validate_path(p, (DOCX_EXT,))
            # 设计文档为 Type A 参考材料（category="design"，区别于写入规则）
            design_docs.append(RuleDocParser().parse(dpath, category="design"))

        return StructuredSource(
            tables=tables,
            template=template,
            rule_docs=rule_docs,
            image_analyses=[],
            existing_system=existing_system,
            comments=comments,
            design_docs=design_docs,
        )