package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"reflect"
	"runtime"
	"slices"
	"sort"
	"strconv"
	"time"

	"github.com/xuri/excelize/v2"
)

type Input struct {
	Tracking struct {
		AvgCpu struct {
			Tin    Record `json:"Tin"`
			Bronze Record `json:"Bronze"`
			Silver Record `json:"Silver"`
			Gold   Record `json:"Gold"`
		} `json:"AVG vCPUs"`
		AvgRam     Record `json:"Avg RAM (GB)"`
		ProVmCount Record `json:"ProRated VM Count"`
		VmCount    Record `json:"VM Name"`
	} `json:"Tracking"`
}

type Record struct {
	Ryde json.RawMessage `json:"Ryde Computer Centre"`
	Wsdc json.RawMessage `json:"Western Sydney Data Centre"`
}

type KeyValue struct {
	Key   string
	Value interface{}
}

var sha1ver string   // sha1 revision used to build the program
var buildTime string // when the executable was built

// Add a new key-value pair to the slice
func addData(data []KeyValue, key string, value interface{}) []KeyValue {
	return append(data, KeyValue{Key: key, Value: value})
}

// Find a value by key
func findData(data []KeyValue, key string) (interface{}, bool) {
	for _, kv := range data {
		if kv.Key == key {
			return kv.Value, true
		}
	}
	return nil, false // Return false if key not found
}

func GenerateAvgVcpusCharts(f *excelize.File, data any, name string) {
	var err error
	rydeAvgCpu := []KeyValue{}
	wsdcAvgCpu := []KeyValue{}
	var avgCpuColumns []string

	// Access AvgCpu using reflection
	avgCpuVal := reflect.ValueOf(data)
	avgCpuType := reflect.TypeOf(data)

	// Iterate over each field in AvgCpu
	for i := 0; i < avgCpuVal.NumField(); i++ {
		field := avgCpuVal.Field(i)
		fieldName := avgCpuType.Field(i).Name

		// Create variables to hold unmarshaled data
		var rydeData interface{}
		var wsdcData interface{}

		// Unmarshal Ryde and Wsdc fields into interface{} if they contain valid JSON
		ryde := field.FieldByName("Ryde")
		wsdc := field.FieldByName("Wsdc")

		if len(ryde.Interface().(json.RawMessage)) > 0 {
			err = json.Unmarshal(ryde.Interface().(json.RawMessage), &rydeData)
			if err != nil {
				fmt.Printf("Error unmarshaling Ryde for %s: %v\n", fieldName, err)
				return
			}
		}

		if len(wsdc.Interface().(json.RawMessage)) > 0 {
			err = json.Unmarshal(wsdc.Interface().(json.RawMessage), &wsdcData)
			if err != nil {
				fmt.Printf("Error unmarshaling Wsdc for %s: %v\n", fieldName, err)
				return
			}
		}

		rydeAvgCpu = addData(rydeAvgCpu, fieldName, rydeData)
		wsdcAvgCpu = addData(wsdcAvgCpu, fieldName, wsdcData)

		//rydeAvgCpu[fieldName] = rydeData
		//wsdcAvgCpu[fieldName] = wsdcData
		avgCpuColumns = append(avgCpuColumns, fieldName)
	}

	// Generate RCC worksheet and graph
	AvgChart(f, name+" RCC", "A1", avgCpuColumns, rydeAvgCpu, 0)
	// Generate WSDC worksheet and graph
	AvgChart(f, name+" WSDC", "N1", avgCpuColumns, wsdcAvgCpu, 0)
}

func GenerateCharts(f *excelize.File, data any, name string, location string, yMaxValue float64) {
	var err error
	//parsedData := make(map[string]interface{})
	parsedData := []KeyValue{}
	var dataColumns = []string{"RCC", "WSDC"}

	// Create interfaces to hold unmarshaled data
	var rcc interface{}
	var wsdc interface{}

	// Access specific json objects using reflection
	values := reflect.ValueOf(data)
	rccField := values.FieldByName("Ryde")
	wsdcField := values.FieldByName("Wsdc")

	// unmarshal raw json into interfaces
	if len(rccField.Interface().(json.RawMessage)) > 0 {
		err = json.Unmarshal(rccField.Interface().(json.RawMessage), &rcc)
		if err != nil {
			fmt.Printf("Error unmarshaling Ryde: %v\n", err)
			return
		}
	}
	if len(wsdcField.Interface().(json.RawMessage)) > 0 {
		err = json.Unmarshal(wsdcField.Interface().(json.RawMessage), &wsdc)
		if err != nil {
			fmt.Printf("Error unmarshaling Wsdc: %v\n", err)
			return
		}
	}

	// store the data together
	parsedData = addData(parsedData, "RCC", rcc)
	parsedData = addData(parsedData, "WSDC", wsdc)
	//parsedData["RCC"] = rcc
	//parsedData["WSDC"] = wsdc
	//prettyPrint(parsedData)

	// Generate worksheet and graph
	AvgChart(f, name, location, dataColumns, parsedData, yMaxValue)
}

func AvgChart(f *excelize.File, worksheetName string, location string, avgCpuColumns []string, data []KeyValue, yMaxValue float64) {
	var err error
	var chartSeries []excelize.ChartSeries
	var dataDates []string
	var col int
	var row int

	fmt.Printf("Creating worksheet %s\n", worksheetName)
	_, err = f.NewSheet(worksheetName)
	if err != nil {
		log.Fatal(err)
	}

	// Create column headers dynamically
	f.SetCellValue(worksheetName, "A1", "Date")
	for i := 0; i < len(avgCpuColumns); i++ {
		cell := string(rune('A'+i+1)) + "1" // A1, B1, C1, etc.
		f.SetCellValue(worksheetName, cell, avgCpuColumns[i])
	}

	// Get the values for the dates column using the first object in data
	for _, v := range data {
		if dateMap, ok := v.Value.(map[string]interface{}); ok {
			for date := range dateMap {
				dataDates = append(dataDates, date)
			}
		}
		break // Assuming you only need the dates from the first entry
	}

	// Sort dates using the custom function
	err = sortDates(dataDates)
	if err != nil {
		fmt.Printf("Failed to sort dates for worksheet %s: %s\n", worksheetName, err)
		return
	}

	// set the values for the dates column
	for i := 0; i < len(dataDates); i++ {
		cell := string(rune('A')) + strconv.Itoa(i+2) // A2, A3 etc
		f.SetCellValue(worksheetName, cell, dataDates[i])
	}

	// Iterate over each KeyValue in the data slice (resource pool types)
	for _, poolKv := range data {
		pool := poolKv.Key // The pool name

		// Find the column that matches, add one to account for the date column
		col = slices.Index(avgCpuColumns, pool) + 1
		//fmt.Printf("Pool: %s, column: %d\n", pool, col)

		// Type assertion to confirm that poolKv.Value is a map[string]interface{}
		if dateMap, ok := poolKv.Value.(map[string]interface{}); ok {
			for date, val := range dateMap {
				//fmt.Printf("Date: %s, Value: %v\n", date, val)

				// Find the correct row, add one to account for sheet heading
				row = slices.Index(dataDates, date) + 1

				cell := string(rune('A'+col)) + strconv.Itoa(row+1)
				//fmt.Printf("Adding value %f (%s) to %s]\n", val, date, cell)
				f.SetCellValue(worksheetName, cell, val)
			}
		}
		// Create the chartseries for this resource pool
		thisChartSeries := excelize.ChartSeries{
			Name:       "'" + worksheetName + "'!$" + string(rune('A'+col)) + "$1",                                                                  // Reference the cell containing the resource pool name, eg Tin in $B$1
			Categories: "'" + worksheetName + "'!$A$2:$A$" + strconv.Itoa(len(dataDates)+1),                                                         // Reference the dates in the first column eg $A$2:$A$5
			Values:     "'" + worksheetName + "'!$" + string(rune('A'+col)) + "$2:$" + string(rune('A'+col)) + "$" + strconv.Itoa(len(dataDates)+1), // Reference the values in the column matching the resource pool name, eg Tin in $B$2:$B$5
			Line: excelize.ChartLine{
				Smooth: true,
			},
		}
		//prettyPrint(thisChartSeries)
		chartSeries = append(chartSeries, thisChartSeries)
	}

	if err := f.AddChart("Report", location, &excelize.Chart{
		Type:   excelize.Line,
		Series: chartSeries,
		Format: excelize.GraphicOptions{
			OffsetX: 5,
			OffsetY: 5,
		},
		Legend: excelize.ChartLegend{
			Position: "right",
		},
		Title: []excelize.RichTextRun{
			{
				Text: worksheetName,
			},
		},
		PlotArea: excelize.ChartPlotArea{
			ShowCatName:     false,
			ShowLeaderLines: false,
			ShowPercent:     true,
			ShowSerName:     false,
			ShowVal:         false,
		},
		ShowBlanksAs: "zero",
		XAxis: excelize.ChartAxis{
			MajorGridLines: true,
			MinorGridLines: true,
			Title: []excelize.RichTextRun{
				{
					Text: "Month Year",
				},
			},
			Font: excelize.Font{
				Color: "000000",
			},
		},
		YAxis: excelize.ChartAxis{
			MajorGridLines: true,
			MinorGridLines: true,
			Title: []excelize.RichTextRun{
				{
					Text: "Count/Size",
				},
			},
			Font: excelize.Font{
				Color: "000000",
			},
			Maximum: *yMaxValue,
		},
		Dimension: excelize.ChartDimension{
			Height: 500,
			Width:  800,
		},
	}); err != nil {
		fmt.Printf("Error adding chart to workbook %s at location %s: %s\n", worksheetName, location, err)
		return
	}
}

func main() {
	var err error

	inputFile := flag.String("input", "input.json", "The filename from which to load historical data")
	outputFile := flag.String("output", "book1.xlsx", "The filename to use when writing excel workbook")
	flag.Parse()

	fmt.Println("Excel chart generation utility, written by Nathan Coad (nathan.coad@dell.com)")
	fmt.Printf("Built on %s from sha1 %s\n", buildTime, sha1ver)

	// Create the workbook
	f := excelize.NewFile()
	defer func() {
		if err := f.Close(); err != nil {
			fmt.Printf("Error closing excel sheet: %s\n", err)
			os.Exit(1)
		}
	}()
	err = f.SetSheetName("Sheet1", "Report")
	if err != nil {
		fmt.Printf("Error renaming Sheet1: %s\n", err)
		os.Exit(1)
	}

	// Load the JSON data from file
	file, err := os.Open(*inputFile)
	if err != nil {
		log.Fatalf("Failed to open input.json: %v", err)
	}
	defer file.Close()

	byteValue, _ := io.ReadAll(file)
	var data Input
	if err := json.Unmarshal(byteValue, &data); err != nil {
		fmt.Printf("Error reading json input: %s\n", err)
		os.Exit(1)
	}

	// Generate charts into workbook
	GenerateAvgVcpusCharts(f, data.Tracking.AvgCpu, "Average vCPUs")
	GenerateCharts(f, data.Tracking.AvgRam, "Average RAM(GB)", "A30", 0)
	GenerateCharts(f, data.Tracking.ProVmCount, "ProRated VM Count", "A60", 10000)
	GenerateCharts(f, data.Tracking.VmCount, "VM Count", "N60", 10000)

	// Save workbook
	if err := f.SaveAs(*outputFile); err != nil {
		fmt.Printf("Error saving excel workbook: %s\n", err)
		os.Exit(1)
	}
}

// parseDate parses a date string like "January-2006" into a time.Time object
func parseDate(dateStr string) (time.Time, error) {
	layout := "January-2006"
	return time.Parse(layout, dateStr)
}

// sortDates sorts a slice of date strings in the format "Month-Year"
func sortDates(dates []string) error {
	// Custom sort logic
	sort.Slice(dates, func(i, j int) bool {
		date1, err1 := parseDate(dates[i])
		date2, err2 := parseDate(dates[j])

		if err1 != nil || err2 != nil {
			fmt.Println("Error parsing dates:", err1, err2)
			return false
		}

		// Compare parsed dates
		return date1.Before(date2)
	})
	return nil
}

func fetchValue(value interface{}) {
	switch value.(type) {
	case string:
		fmt.Printf("%v is an interface \n ", value)
	case bool:
		fmt.Printf("%v is bool \n ", value)
	case float64:
		fmt.Printf("%v is float64 \n ", value)
	case []interface{}:
		fmt.Printf("%v is a slice of interface \n ", value)
		for _, v := range value.([]interface{}) { // use type assertion to loop over []interface{}
			fetchValue(v)
		}
	case map[string]interface{}:
		fmt.Printf("%v is a map \n ", value)
		for _, v := range value.(map[string]interface{}) { // use type assertion to loop over map[string]interface{}
			fetchValue(v)
		}
	default:
		fmt.Printf("%v is unknown \n ", value)
	}
}

// prettyPrint comes from https://gist.github.com/sfate/9d45f6c5405dc4c9bf63bf95fe6d1a7c
func prettyPrint(args ...interface{}) {
	var caller string

	timeNow := time.Now().Format("01-02-2006 15:04:05")
	prefix := fmt.Sprintf("[%s] %s -- ", "PrettyPrint", timeNow)
	_, fileName, fileLine, ok := runtime.Caller(1)

	if ok {
		caller = fmt.Sprintf("%s:%d", fileName, fileLine)
	} else {
		caller = ""
	}

	fmt.Printf("\n%s%s\n", prefix, caller)

	if len(args) == 2 {
		label := args[0]
		value := args[1]

		s, _ := json.MarshalIndent(value, "", "\t")
		fmt.Printf("%s%s: %s\n", prefix, label, string(s))
	} else {
		s, _ := json.MarshalIndent(args, "", "\t")
		fmt.Printf("%s%s\n", prefix, string(s))
	}
}