package quote

import (
	"bytes"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"chat-agent-system/templates"
	"github.com/xuri/excelize/v2"
)

var StatutoryNotes = []string{
	"1）以上价格覆盖服务范围：原理样机验证，工程样机开发，送检样机开发",
	"2）以上价格不含样机物料费用，如需乙方采购，另行商议",
	"3）以上不含开发阶段使用的专用测试设备和工具工装费用",
	"4）以上价格不包括药监局、医疗器械检验所等任何委托测试的第三方费用，第三方费用由甲方直接与第三方结算",
	"5）以上未计算临床阶段费用",
	"6）不含无菌耗材委托生产费用（CMO)",
	"7）不含体系搭建费用",
}

const (
	bufferRate = 0.20
	marginRate = 0.40
	taxRate    = 0.07
	hoursPerPM = 160.0
)

// ValidateInput B5 输入范围校验：畸形输入 fail-closed，不产出报价文件。
func ValidateInput(in Input) error {
	if in.CustomerName == "" || in.ProductName == "" {
		return fmt.Errorf("quote: customer_name and product_name are required")
	}
	if len(in.Hours) == 0 {
		return fmt.Errorf("quote: hours must not be empty")
	}
	for role, h := range in.Hours {
		if isInvalidFloat(h) || h < 0 {
			return fmt.Errorf("quote: hours[%s]=%v must be a non-negative finite number", role, h)
		}
	}
	return nil
}

func isInvalidFloat(v float64) bool {
	return v != v || v > 1.7976931348623157e+307*1.0000000000000002 || v < -1.7976931348623157e+307*1.0000000000000002
}

// reviewSummary B5 轻量复核：行合计与费率组合自洽性不变式，失衡返回错误。
func reviewSummary(summary *Summary) error {
	var sumPY, sumCost, sumBuf, sumMar, sumTax, sumPrice float64
	for _, l := range summary.Lines {
		if l.Cost+bufferFudge(l.Cost) < 0 { // 防御：非有限值已被 ValidateInput 拦截，此处冗余校验
			return fmt.Errorf("quote: line %s cost invalid", l.Code)
		}
		sumPY += l.PersonYear
		sumCost += l.Cost
		sumBuf += l.Buffer
		sumMar += l.Margin
		sumTax += l.Tax
		sumPrice += l.Price
	}
	if !approxEqual(sumPrice, summary.TotalPrice) {
		return fmt.Errorf("quote: line price sum %.2f != total %.2f", sumPrice, summary.TotalPrice)
	}
	if !approxEqual(sumBuf, sumCost*bufferRate) {
		return fmt.Errorf("quote: buffer sum %.2f != cost*%.0f%%", sumBuf, bufferRate*100)
	}
	if !approxEqual(sumMar, (sumCost+sumBuf)*marginRate) {
		return fmt.Errorf("quote: margin sum %.2f != (cost+buffer)*%.0f%%", sumMar, marginRate*100)
	}
	if !approxEqual(sumTax, (sumCost+sumBuf+sumMar)*taxRate) {
		return fmt.Errorf("quote: tax sum %.2f != (cost+buffer+margin)*%.0f%%", sumTax, taxRate*100)
	}
	return nil
}

func bufferFudge(v float64) float64 { return 0 }

func approxEqual(a, b float64) bool {
	diff := a - b
	if diff < 0 {
		diff = -diff
	}
	scale := b
	if scale < 0 {
		scale = -scale
	}
	if scale < 1 {
		scale = 1
	}
	return diff <= scale*1e-6
}

func CalculateAndFill(in Input, templateXlsx string, outPath string) (*Summary, error) {
	if err := ValidateInput(in); err != nil {
		return nil, err
	}
	if _, err := os.Stat(templateXlsx); err != nil {
		wd, _ := os.Getwd()
		dir := wd
		for i := 0; i < 10; i++ {
			p := filepath.Join(dir, templateXlsx)
			if _, err := os.Stat(p); err == nil {
				templateXlsx = p
				break
			}
			parent := filepath.Dir(dir)
			if parent == dir {
				break
			}
			dir = parent
		}
	}

	var f *excelize.File
	if tf, err := excelize.OpenFile(templateXlsx); err == nil {
		f = tf
	} else if eb, eerr := templates.XlsxAssets.ReadFile(strings.TrimPrefix(filepath.ToSlash(templateXlsx), "templates/")); eerr == nil {
		ef, oerr := excelize.OpenReader(bytes.NewReader(eb))
		if oerr != nil {
			return nil, fmt.Errorf("open embedded template %s: %w", templateXlsx, oerr)
		}
		f = ef
	} else {
		return nil, fmt.Errorf("open template %s: %w", templateXlsx, err)
	}
	defer f.Close()

	var totalHours float64
	for _, h := range in.Hours {
		totalHours += h
	}

	pm := totalHours / hoursPerPM
	baseCost := totalHours * 150.0
	bufferVal := baseCost * bufferRate
	marginVal := (baseCost + bufferVal) * marginRate
	preTax := baseCost + bufferVal + marginVal
	taxVal := preTax * taxRate
	totalPrice := preTax + taxVal

	summary := &Summary{
		CustomerName: in.CustomerName,
		ProductName:  in.ProductName,
		TotalPrice:   totalPrice,
		Notes:        StatutoryNotes,
		Lines: []SummaryLine{
			{Code: "ID2", Name: "产品规划", PersonYear: pm * 0.1, Cost: baseCost * 0.1, Buffer: bufferVal * 0.1, Margin: marginVal * 0.1, Tax: taxVal * 0.1, Price: totalPrice * 0.1},
			{Code: "ID3.3.1", Name: "设计开发工程化", PersonYear: pm * 0.7, Cost: baseCost * 0.7, Buffer: bufferVal * 0.7, Margin: marginVal * 0.7, Tax: taxVal * 0.7, Price: totalPrice * 0.7},
			{Code: "ID6", Name: "DHF文档编写", PersonYear: pm * 0.2, Cost: baseCost * 0.2, Buffer: bufferVal * 0.2, Margin: marginVal * 0.2, Tax: taxVal * 0.2, Price: totalPrice * 0.2},
		},
	}

	// B5 轻量复核：不变式失衡即失败，不落盘 Excel。
	if err := reviewSummary(summary); err != nil {
		return nil, fmt.Errorf("quote review failed: %w", err)
	}

	sheet := "报价模型"
	if idx, _ := f.GetSheetIndex(sheet); idx != -1 {
		_ = f.SetCellValue(sheet, "B3", in.CustomerName)
		_ = f.SetCellValue(sheet, "B4", in.ProductName)
		_ = f.SetCellValue(sheet, "B5", totalPrice)

		_ = f.SetCellValue(sheet, "A7", "报价代码")
		_ = f.SetCellValue(sheet, "B7", "服务阶段与内容")
		_ = f.SetCellValue(sheet, "D7", "人年(PM)")
		_ = f.SetCellValue(sheet, "E7", "基础成本(元)")
		_ = f.SetCellValue(sheet, "F7", "缓冲金(20%)")
		_ = f.SetCellValue(sheet, "G7", "毛利(40%)")
		_ = f.SetCellValue(sheet, "H7", "税费(7%)")
		_ = f.SetCellValue(sheet, "J7", "综合报价(元)")

		writeSummaryLine(f, sheet, 8, summary.Lines[0])
		writeSummaryLine(f, sheet, 9, summary.Lines[1])
		writeSummaryLine(f, sheet, 10, summary.Lines[2])

		var totalPersonYear, totalCost, totalBuffer, totalMargin, totalTax float64
		for _, line := range summary.Lines {
			totalPersonYear += line.PersonYear
			totalCost += line.Cost
			totalBuffer += line.Buffer
			totalMargin += line.Margin
			totalTax += line.Tax
		}
		writeSummaryLine(f, sheet, 18, SummaryLine{
			Code:       "总计",
			Name:       "全阶段综合报价",
			PersonYear: totalPersonYear,
			Cost:       totalCost,
			Buffer:     totalBuffer,
			Margin:     totalMargin,
			Tax:        totalTax,
			Price:      totalPrice,
		})
	}

	if err := os.MkdirAll(filepath.Dir(outPath), 0o755); err != nil {
		return nil, err
	}
	if err := f.SaveAs(outPath); err != nil {
		return nil, fmt.Errorf("save filled quote xlsx: %w", err)
	}

	return summary, nil
}

func writeSummaryLine(f *excelize.File, sheet string, row int, line SummaryLine) {
	_ = f.SetCellValue(sheet, fmt.Sprintf("A%d", row), line.Code)
	_ = f.SetCellValue(sheet, fmt.Sprintf("B%d", row), line.Name)
	_ = f.SetCellValue(sheet, fmt.Sprintf("D%d", row), line.PersonYear)
	_ = f.SetCellValue(sheet, fmt.Sprintf("E%d", row), line.Cost)
	_ = f.SetCellValue(sheet, fmt.Sprintf("F%d", row), line.Buffer)
	_ = f.SetCellValue(sheet, fmt.Sprintf("G%d", row), line.Margin)
	_ = f.SetCellValue(sheet, fmt.Sprintf("H%d", row), line.Tax)
	_ = f.SetCellValue(sheet, fmt.Sprintf("J%d", row), line.Price)
}