"""打印服务：单据上下文构建 + 默认模板 + 整页 HTML 输出。"""

from __future__ import annotations

from datetime import datetime
from decimal import Decimal

from django.utils import timezone
from django.utils.html import escape

from apps.core.base_models import TenantScopedModel
from .models import PrintSettings, PrintTemplate
from .renderer import render_template


# ============================================================
# 上下文构建
# ============================================================

def _line_ctx(line, *, index: int) -> dict:
    product = line.product
    unit = line.source_unit or product.base_unit
    # 出库单的行带 FEFO 分摊明细（batch_detail），进货单行直接带批次号
    batch_no = getattr(line, "batch_no", "") or ""
    batch_text = batch_no
    movement_batches = _movement_batches(line)
    if movement_batches:
        batch_text = "／".join(movement_batches)
    return {
        "index": index + 1,
        "product_code": product.code,
        "product_name": product.name,
        "spec": product.spec,
        "quantity": line.quantity,
        "source_quantity": line.source_quantity if line.source_quantity is not None else line.quantity,
        "unit_name": unit.name if unit else "",
        "unit_price": line.unit_price,
        "amount": line.amount,
        "batch_no": batch_text,
        "has_batch": bool(batch_text),
        "is_batch_managed": bool(getattr(product, "is_batch_managed", False)),
    }


def _movement_batches(line) -> list:
    """从该行商品对应的最新出库流水里取批次分摊明细（销售单打印批次列用）。"""
    bill = getattr(line, "bill", None)
    if bill is None or not getattr(bill, "bill_no", ""):
        return []
    from apps.inventory.models import StockMovement

    mv = (
        StockMovement.objects.filter(
            tenant=bill.tenant, source_ref=bill.bill_no, product_id=line.product_id,
        )
        .exclude(batch_detail=[])
        .order_by("-id")
        .first()
    )
    if mv is None or not mv.batch_detail:
        return []
    return [str(b.get("batch_no") or "") for b in mv.batch_detail]


def sales_bill_context(bill) -> dict:
    from apps.printing.models import PrintSettings

    settings_obj = PrintSettings.objects.filter(tenant=bill.tenant).first()
    lines = [_line_ctx(ln, index=i) for i, ln in enumerate(bill.lines.select_related(
        "product", "product__base_unit", "source_unit").all())]
    total_amount = bill.total_amount or Decimal("0")
    round_off = getattr(bill, "round_off", None) or Decimal("0")
    return {
        "company": {
            "name": settings_obj.company_name if settings_obj else "",
            "phone": settings_obj.phone if settings_obj else "",
            "address": settings_obj.address if settings_obj else "",
            "bank_info": settings_obj.bank_info if settings_obj else "",
            "footer_note": settings_obj.footer_note if settings_obj else "",
        },
        "bill": {
            "bill_no": bill.bill_no,
            "bill_date": bill.bill_date.isoformat(),
            "state": bill.state,
            "remark": bill.remark,
            "amount": total_amount,
            "round_off": round_off,
        },
        "customer": {
            "code": bill.customer.code,
            "name": bill.customer.name,
            "phone": bill.customer.phone,
            "address": bill.customer.address,
            "tax_number": bill.customer.tax_number,
        },
        "warehouse": {"code": bill.warehouse.code, "name": bill.warehouse.name},
        "lines": lines,
        "has_batch_lines": any(l["has_batch"] for l in lines),
        "totals": {
            "count": len(lines),
            "quantity": sum(l["quantity"] for l in lines),
            "amount": total_amount + round_off,
            "round_off": round_off,
            "net_amount": total_amount,
        },
        "statement_qr": _statement_qr(bill),
        "printed_at": timezone.localtime().strftime("%Y-%m-%d %H:%M"),
    }


def _statement_qr(bill):
    """销售单尾部的对账单二维码（D5）。失败/无客户时返回 None（模板自动跳过）。"""
    try:
        from .qr import statement_qr_context

        return statement_qr_context(bill.tenant, bill.customer)
    except Exception:
        return None


def purchase_bill_context(bill) -> dict:
    settings_obj = PrintSettings.objects.filter(tenant=bill.tenant).first()
    lines = [_line_ctx(ln, index=i) for i, ln in enumerate(bill.lines.select_related(
        "product", "product__base_unit", "source_unit").all())]
    return {
        "company": {
            "name": settings_obj.company_name if settings_obj else "",
            "phone": settings_obj.phone if settings_obj else "",
            "address": settings_obj.address if settings_obj else "",
            "bank_info": settings_obj.bank_info if settings_obj else "",
            "footer_note": settings_obj.footer_note if settings_obj else "",
        },
        "bill": {
            "bill_no": bill.bill_no,
            "bill_date": bill.bill_date.isoformat(),
            "state": bill.state,
            "remark": bill.remark,
            "amount": bill.total_amount or Decimal("0"),
            "round_off": getattr(bill, "round_off", None) or Decimal("0"),
        },
        "supplier": {
            "code": bill.supplier.code,
            "name": bill.supplier.name,
            "phone": bill.supplier.phone,
            "address": bill.supplier.address,
        },
        "warehouse": {"code": bill.warehouse.code, "name": bill.warehouse.name},
        "lines": lines,
        "has_batch_lines": any(l["has_batch"] for l in lines),
        "totals": {
            "count": len(lines),
            "quantity": sum(l["quantity"] for l in lines),
            "amount": bill.total_amount or Decimal("0"),
            "round_off": Decimal("0"),
            "net_amount": bill.total_amount or Decimal("0"),
        },
        "printed_at": timezone.localtime().strftime("%Y-%m-%d %H:%M"),
    }


DOC_CONTEXT_BUILDERS = {
    "sales_bill": ("apps.sales.models", "SalesBill", sales_bill_context),
    "purchase_bill": ("apps.purchase.models", "PurchaseBill", purchase_bill_context),
}


# ============================================================
# 默认模板
# ============================================================

SALES_BILL_DEFAULT = """
<div class="doc-head">
  <h1>{{company.name}}</h1>
  <div class="sub">电话：{{company.phone}}　地址：{{company.address}}</div>
  <h2>销 售 单</h2>
</div>
<table class="meta">
  <tr><td>单号：{{bill.bill_no}}</td><td>日期：{{bill.bill_date}}</td><td>仓库：{{warehouse.name}}</td></tr>
  <tr><td>客户：{{customer.name}}</td><td>电话：{{customer.phone}}</td><td>打印时间：{{printed_at}}</td></tr>
</table>
<table class="lines">
  <thead><tr><th>#</th><th>编码</th><th>品名</th><th>单位</th><th>数量</th><th>单价</th><th>金额</th>{{#if has_batch_lines}}<th>批次号</th>{{/if}}</tr></thead>
  <tbody>
  {{#each lines}}
    <tr><td>{{item.index}}</td><td>{{item.product_code}}</td><td>{{item.product_name}} {{item.spec}}</td><td>{{item.unit_name}}</td><td>{{item.source_quantity}}</td><td>{{item.unit_price}}</td><td>{{item.amount}}</td>{{#if item.has_batch}}<td>{{item.batch_no}}</td>{{/if}}</tr>
  {{/each}}
  </tbody>
  <tfoot>
    <tr><td colspan="4">合计：{{totals.count}} 行 / 数量 {{totals.quantity}}</td><td colspan="2">抹零优惠</td><td>{{totals.round_off}}</td>{{#if has_batch_lines}}<td></td>{{/if}}</tr>
    <tr><td colspan="6" class="strong">应收合计（元）</td><td class="strong">{{totals.net_amount}}</td>{{#if has_batch_lines}}<td></td>{{/if}}</tr>
  </tfoot>
</table>
<div class="sign">
  <span>制单：__________</span><span>送货人：__________</span><span>客户签收：__________</span>
</div>
<div class="remark">备注：{{bill.remark}}</div>
{{#if statement_qr}}<div class="qr-block">
  <img class="qr-img" src="{{statement_qr.data_uri}}" alt="对账单二维码">
  <div class="qr-tip">{{statement_qr.tip}}</div>
</div>{{/if}}
<div class="foot">{{company.footer_note}}　开户/账号：{{company.bank_info}}</div>
"""

PURCHASE_BILL_DEFAULT = """
<div class="doc-head">
  <h1>{{company.name}}</h1>
  <div class="sub">电话：{{company.phone}}　地址：{{company.address}}</div>
  <h2>进 货 单</h2>
</div>
<table class="meta">
  <tr><td>单号：{{bill.bill_no}}</td><td>日期：{{bill.bill_date}}</td><td>仓库：{{warehouse.name}}</td></tr>
  <tr><td>供应商：{{supplier.name}}</td><td>电话：{{supplier.phone}}</td><td>打印时间：{{printed_at}}</td></tr>
</table>
<table class="lines">
  <thead><tr><th>#</th><th>编码</th><th>品名</th><th>单位</th><th>数量</th><th>单价</th><th>金额</th>{{#if has_batch_lines}}<th>批次号</th>{{/if}}</tr></thead>
  <tbody>
  {{#each lines}}
    <tr><td>{{item.index}}</td><td>{{item.product_code}}</td><td>{{item.product_name}} {{item.spec}}</td><td>{{item.unit_name}}</td><td>{{item.source_quantity}}</td><td>{{item.unit_price}}</td><td>{{item.amount}}</td>{{#if item.has_batch}}<td>{{item.batch_no}}</td>{{/if}}</tr>
  {{/each}}
  </tbody>
  <tfoot>
    <tr><td colspan="4">合计：{{totals.count}} 行 / 数量 {{totals.quantity}}</td><td colspan="{{#if has_batch_lines}}4{{else}}3{{/if}}" class="strong">应付合计（元）：{{totals.net_amount}}</td></tr>
  </tfoot>
</table>
<div class="sign">
  <span>制单：__________</span><span>验收人：__________</span><span>供应商签收：__________</span>
</div>
<div class="foot">{{company.footer_note}}</div>
"""

SALES_RECEIPT_58 = """
<div class="r-head">
  <h1>{{company.name}}</h1>
  <div class="sub">{{company.phone}}</div>
</div>
<div class="r-title">销 售 单</div>
<div class="r-meta">
  单号：{{bill.bill_no}}<br>
  日期：{{bill.bill_date}}<br>
  客户：{{customer.name}}<br>
  仓库：{{warehouse.name}}
</div>
<table class="r-lines">
  <thead>
    <tr><th>品名</th><th class="num">数量</th><th class="num">单价</th><th class="num">金额</th></tr>
  </thead>
  <tbody>
  {{#each lines}}
    <tr>
      <td>{{item.product_name}}</td>
      <td class="num">{{item.source_quantity}}{{item.unit_name}}</td>
      <td class="num">{{item.unit_price}}</td>
      <td class="num">{{item.amount}}</td>
    </tr>
  {{/each}}
  </tbody>
</table>
<div class="r-total">
  共 {{totals.count}} 行{{#if totals.round_off}}　抹零 {{totals.round_off}}{{/if}}<br>
  应收合计：<span class="big">¥{{totals.net_amount}}</span>
</div>
<div class="r-foot">
  {{company.footer_note}}<br>
  打印时间 {{printed_at}}
</div>
"""

# 三联送货单模板
SALES_TRIPLICATE = """
<div class="tpl-page">
  {{#each slips}}
  <div class="tpl-slip">
    <div class="slip-tag">{{item.tag}}</div>
    <h1>{{item.company_name}}</h1>
    <h2>送 货 单</h2>
    <table class="meta">
      <tr><td>单号：{{item.bill_no}}</td><td>日期：{{item.bill_date}}</td></tr>
      <tr><td>客户：{{item.customer_name}}</td><td>电话：{{item.customer_phone}}</td></tr>
      <tr><td colspan="2">地址：{{item.customer_address}}</td></tr>
    </table>
    <table class="lines">
      <thead><tr><th>品名</th><th>数量</th><th>单价</th><th>金额</th></tr></thead>
      <tbody>{{item.lines_html}}</tbody>
    </table>
    <div style="margin-top:6px;font-size:12px">
      合计（元）：<b>{{item.net_amount}}</b>
    </div>
    <div class="sign">
      <span>送货人：______</span><span>客户签收：______</span>
    </div>
  </div>
  {{/each}}
</div>
"""

DEFAULT_TEMPLATES = {
    "sales_bill": [
        ("xs-default", "销售单（默认）", SALES_BILL_DEFAULT),
        ("xs-receipt-58", "销售小票（58mm 热敏）", SALES_RECEIPT_58),
        ("xs-triplicate", "三联送货单（A4 横向）", SALES_TRIPLICATE),
    ],
    "purchase_bill": [("cg-default", "进货单（默认）", PURCHASE_BILL_DEFAULT)],
}

# 模板 → 版式（决定用哪个 HTML 外壳，以及是否横排）
TEMPLATE_SHELL = {
    "xs-receipt-58": "receipt",
    "xs-triplicate": "triplicate",
}


def ensure_default_templates(tenant) -> int:
    """幂等创建租户默认模板（is_default=True）。返回新建数量。"""
    created = 0
    for doc_type, templates in DEFAULT_TEMPLATES.items():
        for code, name, body in templates:
            _, was_created = PrintTemplate.objects.get_or_create(
                tenant=tenant, code=code,
                defaults={
                    "name": name, "doc_type": doc_type,
                    "body_html": body, "is_default": True,
                },
            )
            created += 1 if was_created else 0
    return created


def ensure_settings(tenant) -> PrintSettings:
    obj = PrintSettings.objects.filter(tenant=tenant).first()
    if obj is None:
        obj = PrintSettings.objects.create(
            tenant=tenant, company_name=f"{tenant.name}"
        )
    return obj


# ============================================================
# 渲染输出
# ============================================================

RECEIPT_SHELL = """<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8">
<title>{title}</title>
<style>
  @page {{ size: 58mm auto; margin: 3mm 2mm; }}
  * {{ box-sizing: border-box; }}
  body {{ font-family: "Microsoft YaHei", "SimSun", monospace; font-size: 12px;
         color: #000; margin: 0; width: 54mm; }}
  .r-head {{ text-align: center; }}
  .r-head h1 {{ margin: 0 0 2px; font-size: 15px; }}
  .r-head .sub {{ font-size: 10px; }}
  .r-title {{ text-align: center; font-size: 14px; font-weight: 700;
              margin: 6px 0; letter-spacing: 2px; }}
  .r-meta {{ font-size: 11px; line-height: 1.5; border-bottom: 1px dashed #000;
             padding-bottom: 4px; }}
  .r-lines {{ width: 100%; border-collapse: collapse; margin-top: 4px; font-size: 11px; }}
  .r-lines th {{ border-bottom: 1px solid #000; text-align: left; padding: 2px 0; }}
  .r-lines td {{ padding: 2px 0; vertical-align: top; }}
  .r-lines td.num, .r-lines th.num {{ text-align: right; }}
  .r-total {{ border-top: 1px dashed #000; margin-top: 4px; padding-top: 4px;
              font-size: 12px; }}
  .r-total .big {{ font-size: 15px; font-weight: 700; }}
  .r-foot {{ text-align: center; font-size: 10px; margin-top: 8px;
             border-top: 1px dashed #000; padding-top: 4px; }}
  .noprint {{ margin: 6px 0; }}
  .noprint button {{ width: 100%; padding: 6px; }}
  @media print {{ .noprint {{ display: none; }} }}
</style>
</head>
<body>
<div class="noprint"><button onclick="window.print()">打 印</button></div>
{body}
{script}
</body>
</html>"""

# 三联送货单：A4 横排三份（存根/客户/财务）
TRIPLICATE_SHELL = """<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8">
<title>{title}</title>
<style>
  @page {{ size: A4 landscape; margin: 8mm; }}
  * {{ box-sizing: border-box; }}
  body {{ font-family: "Microsoft YaHei", "SimSun", sans-serif; font-size: 12px;
         color: #111; margin: 0; }}
  .tpl-page {{ display: flex; gap: 6mm; }}
  .tpl-slip {{ flex: 1; border: 1px solid #333; padding: 5mm 4mm;
               display: flex; flex-direction: column; }}
  .tpl-slip .slip-tag {{ text-align: right; font-size: 11px; color: #444; }}
  .tpl-slip h1 {{ margin: 0 0 2px; font-size: 15px; text-align: center; }}
  .tpl-slip h2 {{ margin: 2px 0 8px; font-size: 14px; text-align: center;
                  letter-spacing: 4px; }}
  .tpl-slip table {{ width: 100%; border-collapse: collapse; }}
  .tpl-slip .lines th, .tpl-slip .lines td {{ border: 1px solid #333;
      padding: 2px 3px; font-size: 11px; }}
  .tpl-slip .meta td {{ padding: 1px 2px; font-size: 11px; }}
  .tpl-slip .sign {{ margin-top: auto; padding-top: 10px; font-size: 11px;
                     display: flex; justify-content: space-between; }}
  .noprint {{ margin: 8px 0; }}
  @media print {{ .noprint {{ display: none; }} }}
</style>
</head>
<body>
<div class="noprint"><button onclick="window.print()">打 印（三联）</button></div>
{body}
{script}
</body>
</html>"""

PAGE_SHELL = """<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8">
<title>{title}</title>
<style>
  @page {{ size: {paper} portrait; margin: 12mm 10mm; }}
  * {{ box-sizing: border-box; }}
  body {{ font-family: "Microsoft YaHei", "SimSun", sans-serif; font-size: 13px; color: #111; margin: 0; }}
  .doc-head {{ text-align: center; }}
  .doc-head h1 {{ margin: 0 0 2px; font-size: 20px; }}
  .doc-head h2 {{ margin: 6px 0 10px; font-size: 17px; letter-spacing: 8px; }}
  .doc-head .sub {{ color: #444; font-size: 12px; }}
  table {{ width: 100%; border-collapse: collapse; margin-top: 6px; }}
  .meta td {{ padding: 2px 4px; border: none; }}
  .lines th, .lines td {{ border: 1px solid #333; padding: 4px 6px; text-align: left; }}
  .lines th {{ background: #f2f2f2; }}
  .lines tfoot td {{ border: 1px solid #333; font-size: 13px; }}
  .strong {{ font-weight: 700; font-size: 15px; }}
  .sign {{ margin-top: 22px; display: flex; justify-content: space-between; }}
  .remark {{ margin-top: 10px; white-space: pre-wrap; }}
  .foot {{ margin-top: 14px; color: #555; font-size: 12px; border-top: 1px dashed #999; padding-top: 6px; }}
  .qr-block {{ margin-top: 12px; text-align: center; }}
  .qr-img {{ width: 88px; height: 88px; }}
  .qr-tip {{ font-size: 11px; color: #555; margin-top: 2px; }}
  .noprint {{ margin: 10px 0; }}
  @media print {{ .noprint {{ display: none; }} }}
</style>
</head>
<body>
<div class="noprint"><button onclick="window.print()">打 印</button></div>
{body}
{script}
</body>
</html>"""

AUTO_PRINT_SCRIPT = '<script>window.addEventListener("load", function(){ window.print(); });</script>'


def render_document(*, tenant, doc_type: str, document, template_code: str = "",
                    autoprint: bool = True) -> str:
    """渲染整页可打印 HTML。

    template_code 为空时取该 doc_type 的 is_default 模板（无则用内置默认并落库）。
    """
    from django.apps import apps as django_apps

    ensure_default_templates(tenant)
    ensure_settings(tenant)

    if template_code:
        tpl = PrintTemplate.objects.get(tenant=tenant, code=template_code, doc_type=doc_type)
    else:
        tpl = PrintTemplate.objects.filter(
            tenant=tenant, doc_type=doc_type, is_default=True
        ).first()
        if tpl is None:
            code, name, body = DEFAULT_TEMPLATES[doc_type][0]
            tpl = PrintTemplate.objects.create(
                tenant=tenant, code=code, name=name,
                doc_type=doc_type, body_html=body, is_default=True,
            )

    builder = DOC_CONTEXT_BUILDERS[doc_type][2]
    ctx = builder(document)

    # 版式选择（D5）：模板 code 决定外壳；未登记的走标准 A4
    shell_kind = TEMPLATE_SHELL.get(tpl.code, "page")
    if shell_kind == "triplicate":
        ctx = _triplicate_context(ctx, document)
    body = render_template(tpl.body_html, ctx)
    script = AUTO_PRINT_SCRIPT if autoprint else ""
    title = escape(f"{tpl.name} {document.bill_no}")

    if shell_kind == "receipt":
        return RECEIPT_SHELL.format(title=title, body=body, script=script)
    if shell_kind == "triplicate":
        return TRIPLICATE_SHELL.format(title=title, body=body, script=script)

    paper = "A4" if tpl.paper_size == "A4" else tpl.paper_size
    return PAGE_SHELL.format(
        title=title, paper=paper, body=body, script=script,
    )


def _line_rows_html(lines: list) -> str:
    """把行渲染成 <tr> 串（含转义）。

    三联模板是"循环套循环"，而渲染器的 `item` 只能表示一层——内层再用 item
    会被外层覆盖。这里在 Python 侧先把行拼好，模板里只留一层循环。
    """
    from django.utils.html import escape as _esc

    rows = []
    for ln in lines:
        rows.append(
            "<tr><td>{name}</td><td>{qty}{unit}</td><td>{price}</td><td>{amount}</td></tr>".format(
                name=_esc(str(ln.get("product_name", ""))),
                qty=_esc(str(ln.get("source_quantity", ""))),
                unit=_esc(str(ln.get("unit_name", ""))),
                price=_esc(str(ln.get("unit_price", ""))),
                amount=_esc(str(ln.get("amount", ""))),
            )
        )
    return "".join(rows)


def _triplicate_context(ctx: dict, document) -> dict:
    """三联送货单上下文：把同一份单据复制成三份，各带标签（存根/客户/送货）。"""
    base = {
        "company_name": (ctx.get("company") or {}).get("name", ""),
        "bill_no": (ctx.get("bill") or {}).get("bill_no", ""),
        "bill_date": (ctx.get("bill") or {}).get("bill_date", ""),
        "customer_name": (ctx.get("customer") or {}).get("name", ""),
        "customer_phone": (ctx.get("customer") or {}).get("phone", ""),
        "customer_address": (ctx.get("customer") or {}).get("address", ""),
        "lines_html": _line_rows_html(ctx.get("lines") or []),
        "net_amount": (ctx.get("totals") or {}).get("net_amount", ""),
    }
    slips = [{"tag": tag, **base} for tag in ("① 存根联", "② 客户联", "③ 财务联")]
    return {**ctx, "slips": slips}