package main

import (
	"encoding/json"
	"fmt"
	"math"
	"net/http"
)

type Container struct {
	Length      float64 `json:"length"`
	Width       float64 `json:"width"`
	Height      float64 `json:"height"`
	WeightLimit float64 `json:"weightLimit"`
}

type Box struct {
	Length float64 `json:"length"`
	Width  float64 `json:"width"`
	Height float64 `json:"height"`
	Weight float64 `json:"weight"`
}

type Placement struct {
	X         float64 `json:"x"`
	Y         float64 `json:"y"`
	Z         float64 `json:"z"`
	RotationX float64 `json:"rotationX"`
	RotationY float64 `json:"rotationY"`
	RotationZ float64 `json:"rotationZ"`
	BoxNumber int     `json:"boxNumber"`
}

type Layer struct {
	Count  int         `json:"count"`
	Layout []Placement `json:"layout"`
}

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, "index.html")
	})
	http.HandleFunc("/calculate", func(w http.ResponseWriter, r *http.Request) {
		var data struct {
			Container Container `json:"container"`
			Box       Box       `json:"box"`
		}
		json.NewDecoder(r.Body).Decode(&data)
		layout, strategy, count := optimizePacking(data.Container, data.Box)
		layerMap := make(map[float64][]Placement)
		for _, pos := range layout {
			layerMap[pos.Z] = append(layerMap[pos.Z], pos)
		}
		var layers []Layer
		for _, layer := range layerMap {
			layers = append(layers, Layer{
				Count:  len(layer),
				Layout: layer,
			})
		}
		response := struct {
			Count            int     `json:"count"`
			Layers           []Layer `json:"layers"`
			Strategy         string  `json:"strategy"`
			Density          float64 `json:"density"`
			SpaceUtilization float64 `json:"spaceUtilization"`
			UsedVolume       float64 `json:"usedVolume"`
			TotalWeight      float64 `json:"totalWeight"`
			BoxLength        float64 `json:"boxLength"`
			BoxWidth         float64 `json:"boxWidth"`
			BoxHeight        float64 `json:"boxHeight"`
		}{
			Count:            count,
			Layers:           layers,
			Strategy:         strategy,
			Density:          calculateDensity(data.Container, data.Box, count),
			SpaceUtilization: calculateDensity(data.Container, data.Box, count),
			UsedVolume:       float64(count) * data.Box.Length * data.Box.Width * data.Box.Height,
			TotalWeight:      float64(count) * data.Box.Weight,
			BoxLength:        data.Box.Length,
			BoxWidth:         data.Box.Width,
			BoxHeight:        data.Box.Height,
		}
		json.NewEncoder(w).Encode(response)
	})
	http.ListenAndServe(":8080", nil)
}

func optimizePacking(con Container, box Box) ([]Placement, string, int) {
	rotations := generateRotations(con, box)
	type candidate struct {
		layout   []Placement
		count    int
		strategy string
	}
	var candidates []candidate
	for _, r := range rotations {
		for _, strategy := range []string{"XY", "XZ", "YX", "YZ", "ZX", "ZY"} {
			var xCount, yCount, zCount float64
			switch strategy {
			case "XY":
				xCount = math.Floor(con.Length / r.Length)
				yCount = math.Floor(con.Width / r.Width)
				zCount = math.Floor(con.Height / r.Height)
			case "XZ":
				xCount = math.Floor(con.Length / r.Length)
				zCount = math.Floor(con.Height / r.Height)
				yCount = math.Floor(con.Width / r.Width)
			case "YX":
				yCount = math.Floor(con.Width / r.Length)
				xCount = math.Floor(con.Length / r.Width)
				zCount = math.Floor(con.Height / r.Height)
			case "YZ":
				yCount = math.Floor(con.Width / r.Length)
				zCount = math.Floor(con.Height / r.Height)
				xCount = math.Floor(con.Length / r.Width)
			case "ZX":
				zCount = math.Floor(con.Height / r.Length)
				xCount = math.Floor(con.Length / r.Width)
				yCount = math.Floor(con.Width / r.Height)
			case "ZY":
				zCount = math.Floor(con.Height / r.Length)
				yCount = math.Floor(con.Width / r.Height)
				xCount = math.Floor(con.Length / r.Width)
			}
			totalByVolume := int(xCount * yCount * zCount)
			maxCountByWeight := int(math.Floor(con.WeightLimit / box.Weight))
			actualCount := totalByVolume
			if actualCount > maxCountByWeight {
				actualCount = maxCountByWeight
			}
			if actualCount > 0 {
				candidates = append(candidates, candidate{
					layout:   generateLayout(r, xCount, yCount, zCount, strategy)[:actualCount],
					count:    actualCount,
					strategy: strategy,
				})
			}
		}
	}
	if len(candidates) == 0 {
		return nil, "", 0
	}
	maxCount := 0
	var finalLayout []Placement
	var finalStrategy string
	for _, c := range candidates {
		if c.count > maxCount {
			maxCount = c.count
			finalLayout = c.layout
			finalStrategy = c.strategy
		}
	}
	return finalLayout, finalStrategy, maxCount
}

func generateRotations(con Container, box Box) []Box {
	validRotations := make([]Box, 0)
	for _, r := range []Box{
		{box.Length, box.Width, box.Height, box.Weight},
		{box.Length, box.Height, box.Width, box.Weight},
		{box.Width, box.Length, box.Height, box.Weight},
		{box.Width, box.Height, box.Length, box.Weight},
		{box.Height, box.Length, box.Width, box.Weight},
		{box.Height, box.Width, box.Length, box.Weight},
	} {
		if r.Length <= con.Length &&
			r.Width <= con.Width &&
			r.Height <= con.Height {
			validRotations = append(validRotations, r)
		}
	}
	return validRotations
}

func generateLayout(r Box, xCount, yCount, zCount float64, strategy string) []Placement {
	var layout []Placement
	switch strategy {
	case "XY":
		for x := 0.0; x < xCount; x++ {
			for y := 0.0; y < yCount; y++ {
				for z := 0.0; z < zCount; z++ {
					layout = append(layout, Placement{
						X:         x * r.Length,
						Y:         y * r.Width,
						Z:         z * r.Height,
						RotationX: 0.0,
						RotationY: 0.0,
						RotationZ: 0.0,
						BoxNumber: len(layout),
					})
				}
			}
		}
	case "XZ":
		for x := 0.0; x < xCount; x++ {
			for z := 0.0; z < zCount; z++ {
				for y := 0.0; y < yCount; y++ {
					layout = append(layout, Placement{
						X:         x * r.Length,
						Y:         y * r.Width,
						Z:         z * r.Height,
						RotationX: 0.0,
						RotationY: 0.0,
						RotationZ: 0.0,
						BoxNumber: len(layout),
					})
				}
			}
		}
	case "YX":
		for y := 0.0; y < yCount; y++ {
			for x := 0.0; x < xCount; x++ {
				for z := 0.0; z < zCount; z++ {
					layout = append(layout, Placement{
						X:         x * r.Width,
						Y:         y * r.Length,
						Z:         z * r.Height,
						RotationX: 0.0,
						RotationY: 0.0,
						RotationZ: 0.0,
						BoxNumber: len(layout),
					})
				}
			}
		}
	case "YZ":
		for y := 0.0; y < yCount; y++ {
			for z := 0.0; z < zCount; z++ {
				for x := 0.0; x < xCount; x++ {
					layout = append(layout, Placement{
						X:         x * r.Width,
						Y:         y * r.Length,
						Z:         z * r.Height,
						RotationX: 0.0,
						RotationY: 0.0,
						RotationZ: 0.0,
						BoxNumber: len(layout),
					})
				}
			}
		}
	case "ZX":
		for z := 0.0; z < zCount; z++ {
			for x := 0.0; x < xCount; x++ {
				for y := 0.0; y < yCount; y++ {
					layout = append(layout, Placement{
						X:         x * r.Width,
						Y:         y * r.Height,
						Z:         z * r.Length,
						RotationX: 0.0,
						RotationY: 0.0,
						RotationZ: 0.0,
						BoxNumber: len(layout),
					})
				}
			}
		}
	case "ZY":
		for z := 0.0; z < zCount; z++ {
			for y := 0.0; y < yCount; y++ {
				for x := 0.0; x < xCount; x++ {
					layout = append(layout, Placement{
						X:         x * r.Width,
						Y:         y * r.Height,
						Z:         z * r.Length,
						RotationX: 0.0,
						RotationY: 0.0,
						RotationZ: 0.0,
						BoxNumber: len(layout),
					})
				}
			}
		}
	default:
		fmt.Println("无效排列策略")
	}
	return layout
}

func calculateDensity(con Container, box Box, count int) float64 {
	containerVolume := con.Length * con.Width * con.Height
	boxVolume := float64(count) * box.Length * box.Width * box.Height
	return (boxVolume / containerVolume) * 100
}