package services

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

	"github.com/pdfcpu/pdfcpu/pkg/api"
	"github.com/pdfcpu/pdfcpu/pkg/pdfcpu"
)

type PDFService struct{}

func NewPDFService() *PDFService {
	return &PDFService{}
}

type PDFInfo struct {
	Pages    int    `json:"pages"`
	Title    string `json:"title"`
	Author   string `json:"author"`
	FilePath string `json:"filePath"`
	Size     int64  `json:"size"`
}

func (s *PDFService) GetPDFInfo(filePath string) (*PDFInfo, error) {
	info, err := api.Info(filePath, nil)
	if err != nil {
		return nil, fmt.Errorf("获取PDF信息失败: %v", err)
	}

	fileInfo, err := os.Stat(filePath)
	if err != nil {
		return nil, fmt.Errorf("获取文件信息失败: %v", err)
	}

	return &PDFInfo{
		Pages:    info.Pages,
		Title:    info.Title,
		Author:   info.Author,
		FilePath: filePath,
		Size:     fileInfo.Size(),
	}, nil
}

func (s *PDFService) CompressPDF(inputPath, outputPath string, quality string) error {
	if outputPath == "" {
		outputPath = getOutputPath(inputPath, "_compressed")
	}

	inFile, err := os.Open(inputPath)
	if err != nil {
		return fmt.Errorf("打开输入文件失败: %v", err)
	}
	defer inFile.Close()

	outFile, err := os.Create(outputPath)
	if err != nil {
		return fmt.Errorf("创建输出文件失败: %v", err)
	}
	defer outFile.Close()

	conf := pdfcpu.NewDefaultConfiguration()

	switch quality {
	case "high":
		conf.Quality = 0.9
	case "medium":
		conf.Quality = 0.7
	case "low":
		conf.Quality = 0.5
	default:
		conf.Quality = 0.7
	}

	err = api.Optimize(inFile, outFile, conf)
	if err != nil {
		return fmt.Errorf("压缩PDF失败: %v", err)
	}

	return nil
}

func (s *PDFService) SplitPDF(inputPath, outputDir string, pages string) ([]string, error) {
	if outputDir == "" {
		outputDir = filepath.Dir(inputPath)
	}

	outFiles, err := api.Split(inputPath, outputDir, pages, false, nil)
	if err != nil {
		return nil, fmt.Errorf("分割PDF失败: %v", err)
	}

	return outFiles, nil
}

func (s *PDFService) MergePDFs(inputPaths []string, outputPath string) error {
	if outputPath == "" {
		outputPath = filepath.Join(filepath.Dir(inputPaths[0]), "merged.pdf")
	}

	outFile, err := os.Create(outputPath)
	if err != nil {
		return fmt.Errorf("创建输出文件失败: %v", err)
	}
	defer outFile.Close()

	var inFiles []*os.File
	for _, p := range inputPaths {
		f, err := os.Open(p)
		if err != nil {
			return fmt.Errorf("打开文件失败 %s: %v", p, err)
		}
		defer f.Close()
		inFiles = append(inFiles, f)
	}

	conf := pdfcpu.NewDefaultConfiguration()
	err = api.Merge(inFiles, outFile, conf)
	if err != nil {
		return fmt.Errorf("合并PDF失败: %v", err)
	}

	return nil
}

func (s *PDFService) RotatePDF(inputPath, outputPath string, rotation int) error {
	if outputPath == "" {
		outputPath = getOutputPath(inputPath, "_rotated")
	}

	inFile, err := os.Open(inputPath)
	if err != nil {
		return fmt.Errorf("打开输入文件失败: %v", err)
	}
	defer inFile.Close()

	outFile, err := os.Create(outputPath)
	if err != nil {
		return fmt.Errorf("创建输出文件失败: %v", err)
	}
	defer outFile.Close()

	conf := pdfcpu.NewDefaultConfiguration()
	pages := "1-" // All pages

	err = api.Rotate(inFile, outFile, pages, rotation, conf)
	if err != nil {
		return fmt.Errorf("旋转PDF失败: %v", err)
	}

	return nil
}

func (s *PDFService) AddWatermark(inputPath, outputPath, text string) error {
	if outputPath == "" {
		outputPath = getOutputPath(inputPath, "_watermarked")
	}

	inFile, err := os.Open(inputPath)
	if err != nil {
		return fmt.Errorf("打开输入文件失败: %v", err)
	}
	defer inFile.Close()

	outFile, err := os.Create(outputPath)
	if err != nil {
		return fmt.Errorf("创建输出文件失败: %v", err)
	}
	defer outFile.Close()

	conf := pdfcpu.NewDefaultConfiguration()

	wm, err := pdfcpu.TextWatermark(text, "20pt", true, 0.3, 0)
	if err != nil {
		return fmt.Errorf("创建水印失败: %v", err)
	}

	err = api.AddWatermarks(inFile, outFile, nil, wm, conf)
	if err != nil {
		return fmt.Errorf("添加水印失败: %v", err)
	}

	return nil
}