package file

import (
	"encoding/xml"
	"fmt"
	"io"
	"log/slog"
	"os"
	"strconv"
	"strings"
)

type (
	Kml struct {
		xmlns       string
		xmlVer      string
		styleId     string
		encoding    string
		iconHref    string
		coordinates [][3]float64
	}

	Point struct {
		Coordinates string `xml:"coordinates"`
	}
)

func NewKml() *Kml {
	return &Kml{
		xmlns:    "http://earth.google.com/kml/2.1",
		xmlVer:   "1.0",
		styleId:  "Pt_STYLE",
		encoding: "UTF-8",
		iconHref: "http://maps.google.com/mapfiles/kml/pal3/icon52.png",
	}
}

func (own *Kml) WithXmlns(xmlns string) *Kml {
	own.xmlns = xmlns
	return own
}

func (own *Kml) WithXmlVer(xmlVer string) *Kml {
	own.xmlVer = xmlVer
	return own
}

func (own *Kml) WithStyleId(styleId string) *Kml {
	own.styleId = styleId
	return own
}

func (own *Kml) WithEncoding(encoding string) *Kml {
	own.encoding = encoding
	return own
}

func (own *Kml) WithIconHref(iconHref string) *Kml {
	own.iconHref = iconHref
	return own
}

func (own *Kml) ReadFromFile(filename string) error {
	file, err := os.Open(filename)
	if err != nil {
		return err
	}
	defer file.Close()

	data, err := io.ReadAll(file)
	if err != nil {
		return err
	}

	var points = struct {
		XMLName  xml.Name `xml:"kml"`
		Document struct {
			Placemark []struct {
				Point struct {
					Coordinates string `xml:"coordinates"`
				} `xml:"Point"`
			} `xml:"Placemark"`
		} `xml:"Document"`
	}{}
	if err := xml.Unmarshal(data, &points); err != nil {
		return err
	}

	own.coordinates = make([][3]float64, 0)
	for _, point := range points.Document.Placemark {
		cs := strings.Split(strings.TrimSpace(point.Point.Coordinates), ",")
		cLon, _ := strconv.ParseFloat(cs[0], 64)
		cLat, _ := strconv.ParseFloat(cs[1], 64)
		cTime, _ := strconv.ParseFloat(cs[2], 64)
		own.coordinates = append(own.coordinates, [3]float64{cLon, cLat, cTime})
	}
	return nil
}

func (own *Kml) WriteToFileFromChannel(filename string, data <-chan [3]float64) error {
	// 创建文件
	file, err := os.Create(filename)
	if err != nil {
		return err
	}

	go func() {
		defer file.Close()

		// 写入 KML 文件头部
		if err := own.writeHead(file); err != nil {
			slog.Error(err.Error())
			return
		}

		var point int64 = 1
		for mark := range data {
			if err := own.writeData(file, mark, point); err != nil {
				slog.Error(err.Error())
				return
			}
			point++
		}

		// 写入 KML 文件尾部
		if err := own.writeTail(file); err != nil {
			slog.Error(err.Error())
		}
	}()

	return nil
}

func (own *Kml) WriteToFileFromData(filename string, data [][3]float64) error {
	file, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer file.Close()

	// 写入 KML 文件头部
	if err := own.writeHead(file); err != nil {
		return err
	}

	// 写入数据点
	var point int64 = 1
	for _, mark := range data {
		if err := own.writeData(file, mark, point); err != nil {
			return err
		}
		point++
	}

	// 写入 KML 文件尾部
	return own.writeTail(file)
}

func (own *Kml) writeHead(file *os.File) error {
	head := fmt.Sprintf(`<?xml version="%s" encoding="%s"?>
<kml xmlns="%s" >
	<Document>
		<Style id="%s" >
			<IconStyle>
				<scale>
					1
				</scale>
				<Icon>
				<href>
					%s
				</href>
				</Icon>
			</IconStyle>
		</Style>`, own.xmlVer, own.encoding, own.xmlns, own.styleId, own.iconHref)
	_, err := file.WriteString(head)
	return err
}

func (own *Kml) writeData(file *os.File, data [3]float64, total int64) error {
	coordinate := fmt.Sprintf(`
		<Placemark>
			<name>
				Point%d
			</name>
			<description>
				<![CDATA[<TABLE BORDER=1></TABLE> ]]>
			</description>
			<styleUrl>
			</styleUrl>
			<Point>
				<coordinates>
					%f,%f,0
				</coordinates>
			</Point>
		</Placemark>`, total, data[0], data[1])
	_, err := file.WriteString(coordinate)
	return err
}

func (own *Kml) writeTail(file *os.File) error {
	_, err := file.WriteString(`
	</Document>
</kml>`)
	return err
}