/*
 * MIT License
 *
 * Copyright (c) 2019 Alexey Edelev <semlanik@gmail.com>
 *
 * This file is part of NeuralNetwork project https://git.semlanik.org/semlanik/NeuralNetwork
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and
 * to permit persons to whom the Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies
 * or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

package training

import (
	"bufio"
	"fmt"
	"log"
	"math/rand"
	"os"
	"strconv"
	"strings"
	"sync"
	"time"

	mat "gonum.org/v1/gonum/mat"
)

type TextDataReader struct {
	dataSet   []*mat.Dense
	result    []*mat.Dense
	dataCount int
	mutex     *sync.Mutex
}

func NewTextDataReader(filename string, validationPart int) *TextDataReader {
	r := &TextDataReader{
		mutex:           &sync.Mutex{},
	}
	r.readData(filename)
	r.dataCount = int((float64(len(r.dataSet)) * float64(100.0 - validationPart)) / 100.0)
	return r
}
func (r *TextDataReader) readData(filename string) {
	inputFile, err := os.Open(filename)
	if err != nil {
		log.Fatal(err)
	}

	defer inputFile.Close()

	scanner := bufio.NewScanner(inputFile)
	scanner.Split(bufio.ScanLines)

	var results []string
	var uniqueResults []string
	var max []float64
	for scanner.Scan() {
		dataLine := scanner.Text()
		data := strings.Split(dataLine, ",")
		dataSetSize := len(data) - 1

		if len(max) <= 0 {
			max = make([]float64, dataSetSize)
		}

		if dataSetSize != len(max) {
			fmt.Printf("Garbage record: %s\n", dataLine)
			continue
		}

		var dataRaw []float64
		for i := 0; i < dataSetSize; i++ {
			val, err := strconv.ParseFloat(data[i], 64)
			if err != nil {
				break
			}
			dataRaw = append(dataRaw, val)

			if max[i] < val {
				max[i] = val
			}
		}

		if len(dataRaw) < dataSetSize {
			fmt.Printf("Garbage record: %s\n", dataLine)
			continue
		}
		r.dataSet = append(r.dataSet, mat.NewDense(dataSetSize, 1, dataRaw))

		found := false
		for _, uniqueResult := range uniqueResults {
			if uniqueResult == data[dataSetSize] {
				found = true
				break
			}
		}
		if !found {
			uniqueResults = append(uniqueResults, data[dataSetSize])
		}
		results = append(results, data[dataSetSize])
	}

	for i, result := range results {
		k := 0
		for k, _ = range uniqueResults {
			if uniqueResults[k] == result {
				break
			}
		}
		r.result = append(r.result, mat.NewDense(len(uniqueResults), 1, nil))
		r.result[i].Set(k, 0, 1.0)
	}

	//normalize
	for i := 0; i < len(r.dataSet); i++ {
		r.dataSet[i].Apply(func(r, _ int, val float64) float64 {
			return val / max[r]
		}, r.dataSet[i])
	}

	rand.Seed(time.Now().UnixNano())
	for k := 0; k < 25; k++ {
		rand.Shuffle(len(r.dataSet), func(i, j int) {
			r.result[i], r.result[j] = r.result[j], r.result[i]
			r.dataSet[i], r.dataSet[j] = r.dataSet[j], r.dataSet[i]
		})
	}
}

func (r *TextDataReader) GetData(i int) (*mat.Dense, *mat.Dense) {
	if i >= r.dataCount {
		return nil, nil
	}

	return r.dataSet[i], r.result[i]
}

func (r *TextDataReader) DataCount() int {
	return r.dataCount;
}

func (r *TextDataReader) GetValidator(i int) (*mat.Dense, *mat.Dense) {
	if i >= len(r.result) - r.dataCount {
		return nil, nil
	}

	return r.dataSet[r.dataCount + i], r.result[r.dataCount + i]
}

func (r *TextDataReader) ValidatorCount() int {
	return len(r.result) -  r.dataCount;
}