"""Bounded attachment parsing and field provenance; no macros/formula execution."""
import base64
import csv
import io
import json
import re
import zipfile
from hashlib import sha256
from pathlib import Path
from xml.etree import ElementTree as ET

from services.assistant_store import uid, now
from services.skill_executor import number

FIELDS = {
    "facility_amount": "facility.amount", "lease_asset_value": "lease.total_value",
    "operating_cashflow": "financial.operating_cashflow", "financial_liabilities": "financial.total_liabilities",
    "due_diligence_liabilities": "due_diligence.liabilities", "duplicate_asset_count": "lease.duplicate_count",
    "collection_dependency": "collection.dependency", "collection_evidence": "collection.evidence",
    "financial_assets": "financial.total_assets", "credit_overdue_count": "credit.overdue_count",
    "credit_report_date": "credit.report_date",
    "facility_term": "facility.term",
}
NUMERIC = set(FIELDS.values()) - {"collection.dependency", "collection.evidence", "credit.report_date"}
LIMIT = 10 * 1024 * 1024


def scalar(field, value):
    if value is None or value in ("", "null", "缺失"):
        return None
    if field in NUMERIC:
        result = number(value)
        if field in ("lease.duplicate_count", "credit.overdue_count") and (result < 0 or result != result.to_integral_value()):
            raise ValueError("数量必须为非负整数")
        if field in ("facility.amount", "lease.total_value") and result <= 0:
            raise ValueError("融资金额和租赁物价值必须为正数")
        return str(result)
    if field == "collection.dependency":
        if value not in (True, False, "true", "false", "是", "否"):
            raise ValueError("回款依赖须为布尔值")
        return value in (True, "true", "是")
    return str(value)[:4000]


def safe_zip(content):
    archive = zipfile.ZipFile(io.BytesIO(content))
    if len(archive.infolist()) > 2000 or sum(i.file_size for i in archive.infolist()) > 40 * LIMIT:
        archive.close()
        raise ValueError("压缩包解压尺寸超过限制")
    return archive


def parse(content, filename):
    if not content or len(content) > LIMIT:
        raise ValueError("材料为空或超过 10 MB")
    suffix = Path(filename).suffix.lower()
    chunks, warnings = [], []
    def add(locator, text, **extra):
        if len(chunks) >= 15000:
            raise ValueError("材料内容超过首版处理上限")
        chunks.append({"locator": locator, "text": str(text)[:16000], **extra})
    if suffix in (".txt", ".csv"):
        text = content.decode("utf-8-sig", errors="strict")
        if suffix == ".txt":
            for index, line in enumerate(text.splitlines(), 1):
                add(f"第{index}行", line)
        else:
            for index, row in enumerate(csv.reader(io.StringIO(text)), 1):
                add(f"第{index}行", " | ".join(row), cells=row)
    elif suffix == ".docx":
        with safe_zip(content) as archive:
            root = ET.fromstring(archive.read("word/document.xml"))
        ns = {"w": "http://schemas.openxmlformats.org/wordprocessingml/2006/main"}
        para, table = 0, 0
        for element in root.find("w:body", ns):
            if element.tag.endswith("}p"):
                para += 1
                add(f"正文第{para}段", "".join(t.text or "" for t in element.findall(".//w:t", ns)))
            elif element.tag.endswith("}tbl"):
                table += 1
                for r, row in enumerate(element.findall("w:tr", ns), 1):
                    cells = ["".join(t.text or "" for t in cell.findall(".//w:t", ns)) for cell in row.findall("w:tc", ns)]
                    add(f"表{table}第{r}行", " | ".join(cells), cells=cells)
    elif suffix == ".xlsx":
        ns = {"x": "http://schemas.openxmlformats.org/spreadsheetml/2006/main"}
        with safe_zip(content) as archive:
            strings = []
            if "xl/sharedStrings.xml" in archive.namelist():
                strings = ["".join(t.text or "" for t in s.findall(".//x:t", ns)) for s in ET.fromstring(archive.read("xl/sharedStrings.xml"))]
            rels = {r.get("Id"): r.get("Target") for r in ET.fromstring(archive.read("xl/_rels/workbook.xml.rels"))}
            book = ET.fromstring(archive.read("xl/workbook.xml"))
            for sheet in book.findall("x:sheets/x:sheet", ns):
                target = rels.get(sheet.get("{http://schemas.openxmlformats.org/officeDocument/2006/relationships}id"), "")
                path = target.lstrip("/") if target.startswith("/") else "xl/" + target
                if ".." in path or path not in archive.namelist():
                    raise ValueError("工作表引用无效")
                for row in ET.fromstring(archive.read(path)).findall("x:sheetData/x:row", ns):
                    cells = []
                    for cell in row.findall("x:c", ns):
                        raw = cell.findtext("x:v", default="", namespaces=ns)
                        kind = cell.get("t")
                        text = strings[int(raw)] if kind == "s" and raw else ("".join(t.text or "" for t in cell.findall(".//x:t", ns)) if kind == "inlineStr" else raw)
                        formula = cell.findtext("x:f", namespaces=ns)
                        if formula is not None and raw == "":
                            warnings.append(sheet.get("name") + "!" + cell.get("r") + "公式无缓存，未计算")
                        add(sheet.get("name") + "!" + cell.get("r"), text, formula=formula, cached_value=raw if formula is not None else None)
                        cells.append(text)
                    if cells:
                        add(sheet.get("name") + "!第" + row.get("r") + "行", " | ".join(cells), cells=cells)
    elif suffix in (".pdf", ".png", ".jpg", ".jpeg"):
        from api.collateral_agent import extract_pages
        for page in extract_pages(content, filename):
            add("第" + str(page["number"]) + "页", page.get("text", ""), method=page.get("method"), status=page.get("status"))
            if not page.get("text", "").strip():
                warnings.append("第" + str(page["number"]) + "页未提取到文字，请启用 OCR 或补充可读材料")
    else:
        raise ValueError("支持 TXT、CSV、DOCX、XLSX、PDF、PNG、JPG；不执行宏或外链")
    if sum(len(c["text"]) for c in chunks) > 300000:
        raise ValueError("材料文字超过 30 万字，请拆分")
    return chunks, warnings


def material(project_id, filename, content, actor, version=1):
    filename = Path(filename.replace("\\", "/")).name[:180]
    try:
        chunks, warnings = parse(content, filename)
    except (OSError, zipfile.BadZipFile, ET.ParseError, UnicodeError, csv.Error, IndexError, TypeError) as exc:
        raise ValueError("材料内容损坏、编码不支持或格式不匹配，请检查原文件") from exc
    body = {"id": uid("doc"), "project_id": project_id, "name": filename, "version": version,
            "content_hash": sha256(content).hexdigest(), "created_at": now(), "actor_id": actor,
            "size": len(content), "chunks": chunks, "warnings": warnings,
            "status": "partial" if warnings else "parsed", "raw_base64": base64.b64encode(content).decode(), "candidates": []}
    for chunk in body["chunks"]:
        chunk["evidence_id"] = uid("evdoc")
    asset_rows = [c for c in chunks if c.get("cells")]
    if asset_rows and asset_rows[0]["cells"][:2] == ["asset_id", "value"]:
        assets, duplicates, conflicting = {}, 0, False
        for row in asset_rows[1:]:
            cells = row["cells"]
            if len(cells) < 2 or not cells[0].strip():
                body["warnings"].append(row["locator"] + "缺少设备编号或价值")
                continue
            value = number(cells[1])
            if value <= 0:
                raise ValueError("设备价值必须大于零")
            if cells[0] in assets:
                duplicates += 1
                if assets[cells[0]] != value:
                    conflicting = True
            else:
                assets[cells[0]] = value
        metadata = {"document_id": body["id"], "source": filename, "locator": "设备清单去重计算；" + "、".join(c["locator"] for c in asset_rows[1:]),
                    "currency": "CNY", "unit": "万元", "period": "2025", "scope": "合并", "formula_version": "unique-asset-id-sum@1.0.0"}
        # Only the explicit demo schema below establishes these dimensions. Other asset files require confirmation.
        if asset_rows[0]["cells"][2:] != ["currency=CNY", "unit=万元", "period=2025", "scope=合并"]:
            metadata.update(currency=None, unit=None, period=None, scope=None)
            body["warnings"].append("设备清单未声明币种、单位、期间或口径；人工确认前不得计算覆盖率")
        body["candidates"].extend([{**metadata, "id": uid("candidate"), "field": "lease.duplicate_count", "value": str(duplicates), "unit": "count"},
                                  {**metadata, "id": uid("candidate"), "field": "lease.total_value", "value": None if conflicting or not assets else str(sum(assets.values()))}])
        if conflicting:
            body["warnings"].append("同一设备编号价值不一致，未计算总价值")
        if body["warnings"]:
            body["status"] = "partial"
    for chunk in chunks:
        cells = chunk.get("cells") or re.split(r"[:：=]", chunk["text"], maxsplit=1)
        if len(cells) < 2:
            continue
        field = FIELDS.get(cells[0].strip(), cells[0].strip())
        if field not in FIELDS.values():
            continue
        try:
            value = scalar(field, cells[1].strip())
            body["candidates"].append({"id": uid("candidate"), "field": field, "value": value,
                "document_id": body["id"], "locator": chunk["locator"], "source": filename,
                "currency": cells[2] if len(cells) > 2 else None, "unit": cells[3] if len(cells) > 3 else None,
                "period": cells[4] if len(cells) > 4 else None, "scope": cells[5] if len(cells) > 5 else None})
        except ValueError as exc:
            body["warnings"].append(chunk["locator"] + ": " + str(exc))
            body["status"] = "partial"
    return body


def demo_material(project):
    stream = io.StringIO(newline="")
    writer = csv.writer(stream)
    writer.writerow(["field", "value", "currency", "unit", "period", "scope"])
    for field, value in project["facts"].items():
        name = FIELDS.get(field, field)
        if name not in FIELDS.values():
            continue
        writer.writerow([name, "null" if value is None else (json.dumps(value) if isinstance(value, bool) else value),
                         "CNY" if name in NUMERIC else "", "count" if name.endswith("count") else ("万元" if name in NUMERIC else ""), "2025", "合并"])
    return material(project["id"], project["id"] + "演示源数据.csv", stream.getvalue().encode("utf-8-sig"), "demo-fixture")


def demo_assets(project):
    """Real parseable list; duplicate values are excluded from the amount numerator."""
    amount = number(project["facts"]["lease_asset_value"])
    count = int(number(project["facts"].get("duplicate_asset_count", 0)))
    stream = io.StringIO(newline="")
    writer = csv.writer(stream)
    writer.writerow(["asset_id", "value", "currency=CNY", "unit=万元", "period=2025", "scope=合并"])
    writer.writerow(["ASSET-001", str(amount)])
    for _ in range(count):
        writer.writerow(["ASSET-001", str(amount)])
    return material(project["id"], project["id"] + "设备清单.csv", stream.getvalue().encode("utf-8-sig"), "demo-fixture")


def apply_candidate(project, candidate, actor, reason):
    value = scalar(candidate["field"], candidate.get("value"))
    evidence = dict(candidate, id=uid("ev"), project_id=project["id"], value=value, actor_id=actor, reason=reason, accepted_at=now())
    money_fields = NUMERIC - {"lease.duplicate_count", "credit.overdue_count", "facility.term"}
    if candidate["field"] in money_fields and value is not None and candidate.get("unit"):
        from api.risk_agent_alignment import SCALE
        if candidate["unit"] not in SCALE:
            raise ValueError("不支持的金额单位，请确认元、万元或亿元")
        evidence.update(raw_value=value, raw_unit=candidate["unit"], unit="万元")
        value = str(number(value) * SCALE[candidate["unit"]])
        evidence["value"] = value
    project.setdefault("sources", {}).setdefault(candidate["field"], []).append(evidence)
    project.setdefault("values", {})[candidate["field"]] = value
    project.setdefault("selected_sources", {})[candidate["field"]] = evidence["id"]
    old = next((k for k, v in FIELDS.items() if v == candidate["field"]), candidate["field"])
    project.setdefault("facts", {})[old] = value
    return evidence