package utils

import (
	"fmt"
	"github.com/gen2brain/go-fitz"
	"image/jpeg"
	"os"
	"path/filepath"
	"time"
)

// 一些计算

// ComputeIndividualIncomeTax 计算个人所得税
func ComputeIndividualIncomeTax(income float64) float64 {
	if income <= 800 {
		return 0
	}

	if income <= 4000 {
		income = income - 800
	}

	// 实际纳税金额
	if income > 4000 {
		income = income * 0.8
	}

	// 税率、速算扣除数
	var taxRate, quickDeduction float64

	if income <= 20000 {
		taxRate = 0.2
		quickDeduction = 0
	} else if income <= 50000 {
		taxRate = 0.3
		quickDeduction = 2000
	} else {
		taxRate = 0.4
		quickDeduction = 7000
	}

	incomeTax := income*taxRate - quickDeduction

	return incomeTax
}

// ConvertPDFToImages converts a PDF file to images and saves them in the specified output directory.
func ConvertPDFToImages(pdfPath string, outputDir string, filename string) error {
	// Open the PDF file
	doc, err := fitz.New(pdfPath)
	if err != nil {
		return fmt.Errorf("failed to open PDF file: %v", err)
	}
	defer doc.Close()

	// Ensure the output directory exists
	if err := os.MkdirAll(outputDir, os.ModePerm); err != nil {
		return fmt.Errorf("failed to create output directory: %v", err)
	}

	// Iterate over each page in the PDF
	for i := 0; i < doc.NumPage(); i++ {
		// Render the page to an image
		img, err := doc.Image(i)
		if err != nil {
			return fmt.Errorf("failed to render page %d: %v", i, err)
		}

		// Create the output file
		outputFile := filepath.Join(outputDir, filename)
		file, err := os.Create(outputFile)
		if err != nil {
			return fmt.Errorf("failed to create output file: %v", err)
		}
		defer file.Close()

		// Encode the image as JPEG and save it to the file
		opts := &jpeg.Options{Quality: 80}
		if err := jpeg.Encode(file, img, opts); err != nil {
			return fmt.Errorf("failed to encode image: %v", err)
		}
	}

	return nil
}

// CalculateAge 计算年龄
func CalculateAge(birthdate string) (int, error) {
	// 解析出生日期字符串
	layout := "2006-01-02 15:04:05"
	birthTime, err := time.Parse(layout, birthdate)
	if err != nil {
		return 0, err
	}

	// 获取当前时间
	now := time.Now()

	// 计算年龄
	years := now.Year() - birthTime.Year()

	// 如果今年的生日还没到，年龄减一
	if now.Month() < birthTime.Month() || (now.Month() == birthTime.Month() && now.Day() < birthTime.Day()) {
		years--
	}

	return years, nil
}