package tspreader

import (
	"bufio"
	"errors"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

type TspSpec struct {
	name           string
	problemType    string
	comment        string
	dimension      int
	edgeWeightType string
	edgeWeightFormat string
	data           *TspData
}

type TspData struct {
	datatype string
	values*[][] float64
}

func NewTspData() *TspSpec {
	return &TspSpec{name: "", problemType: "TSP", comment: "", dimension: 0, edgeWeightType: "", data: NewTspDataArray()}
}

func NewTspDataArray() *TspData {
	return &TspData{datatype: "EDGE_WEIGHT_SECTION", values: &[][]float64{}}
}

func (t TspSpec) String() string {
	return fmt.Sprintf("%s [%s] - %s %s %d", t.name, t.problemType, t.edgeWeightType, t.edgeWeightFormat, t.dimension)
}

func (t TspData) String() string {
	return fmt.Sprintf("Datatype: %s", t.datatype)
}

// Read Reads TSP data from .tsp file
func Read(path string) (*TspSpec, error) {
	file, err := os.Open(path)
	if(err != nil) {
		log.Fatal(err)
		return nil, errors.New("unable to open file")
	}
	scanner := bufio.NewScanner(file)

	spec := NewTspData()
	dataLine := -1
	arr := [][]float64{}

	for scanner.Scan() {
		line := scanner.Text()

		// handle Specification Headers
		if strings.Contains(line,":") {
			strs := strings.Split(line, ":")
			switch strings.ReplaceAll(strs[0]," ","") {
			case "NAME": {
				spec.name = strings.ReplaceAll(strs[1]," ","")
			}
			case "TYPE": {
				spec.problemType = strings.ReplaceAll(strs[1]," ","")
			}
			case "COMMENT": {
				spec.comment = strings.ReplaceAll(strs[1]," ","")
			}
			case "DIMENSION": {
				i, e := strconv.ParseInt(strings.ReplaceAll(strs[1]," ",""),10,64)
				if(e == nil) {
					spec.dimension = int(i)
				}
			}
			case "EDGE_WEIGHT_TYPE": {
				spec.edgeWeightType = strings.ReplaceAll(strs[1]," ","")
			}
			case "EDGE_WEIGHT_FORMAT": {
				spec.edgeWeightFormat = strings.ReplaceAll(strs[1]," ","")
			}
			}
		} else {
			// Sace Data as Multi Dimensional Array
			if dataLine == -1 {
				spec.data.datatype = strings.ReplaceAll(line," ","")
				dataLine++
			} else {
				entries := strings.Split(line, " ")

				arr = append(arr, []float64{})

				for _, e := range entries{
					f, err := strconv.ParseFloat(e, 64)
					if err == nil {
						arr[dataLine] = append(arr[dataLine], f)
					}
				}
				dataLine++
			}
		}

	}
	spec.data.values = &arr

	// return specification
	return spec, nil
}