package progress

import (
	"fmt"
	"strings"
	"time"

	"github.com/projectdiscovery/clistats"
	"github.com/projectdiscovery/gologger"
)

// Progress is a progress instance for showing program stats
type Progress struct {
	stats        clistats.StatisticsClient
	tickDuration time.Duration
}

// NewProgress creates and returns a new progress tracking object.
func NewProgress(active bool) *Progress {
	var tickDuration time.Duration
	if active {
		tickDuration = 1 * time.Second
	} else {
		tickDuration = -1
	}

	progress := &Progress{
		tickDuration: tickDuration,
		stats:        clistats.New(),
	}
	return progress
}

// Init initializes the progress display mechanism by setting counters, etc.
func (p *Progress) Init(hostCount int64, rulesCount int, requestCount int64) {
	p.stats.AddStatic("templates", rulesCount)
	p.stats.AddStatic("hosts", hostCount)
	p.stats.AddStatic("startedAt", time.Now())
	p.stats.AddCounter("requests", uint64(0))
	p.stats.AddCounter("errors", uint64(0))
	p.stats.AddCounter("total", uint64(requestCount))

	_ = p.stats.Start(makePrintCallback(), p.tickDuration)
}

// AddToTotal adds a value to the total request count
func (p *Progress) AddToTotal(delta int64) {
	p.stats.IncrementCounter("total", int(delta))
}

// Update progress tracking information and increments the request counter by one unit.
func (p *Progress) Update() {
	p.stats.IncrementCounter("requests", 1)
}

// Drop drops the specified number of requests from the progress bar total.
// This may be the case when uncompleted requests are encountered and shouldn't be part of the total count.
func (p *Progress) Drop(count int64) {
	// mimic dropping by incrementing the completed requests
	p.stats.IncrementCounter("errors", int(count))
}

const bufferSize = 128

func makePrintCallback() func(stats clistats.StatisticsClient) {
	builder := &strings.Builder{}
	builder.Grow(bufferSize)

	return func(stats clistats.StatisticsClient) {
		builder.WriteRune('[')
		startedAt, _ := stats.GetStatic("startedAt")
		duration := time.Since(startedAt.(time.Time))
		builder.WriteString(fmtDuration(duration))
		builder.WriteRune(']')

		templates, _ := stats.GetStatic("templates")
		builder.WriteString(" | Templates: ")
		builder.WriteString(clistats.String(templates))
		hosts, _ := stats.GetStatic("hosts")
		builder.WriteString(" | Hosts: ")
		builder.WriteString(clistats.String(hosts))

		requests, _ := stats.GetCounter("requests")
		total, _ := stats.GetCounter("total")

		builder.WriteString(" | ")
		builder.WriteString(clistats.String(uint64(float64(requests) / duration.Seconds())))
		builder.WriteRune(' ')
		builder.WriteString("RPS")

		errors, _ := stats.GetCounter("errors")
		builder.WriteString(" | Errors: ")
		builder.WriteString(clistats.String(errors))

		builder.WriteString(" | Requests: ")
		builder.WriteString(clistats.String(requests))
		builder.WriteRune('/')
		builder.WriteString(clistats.String(total))
		builder.WriteRune(' ')
		builder.WriteRune('(')
		//nolint:gomnd // this is not a magic number
		builder.WriteString(clistats.String(uint64(float64(requests) / float64(total) * 100.0)))
		builder.WriteRune('%')
		builder.WriteRune(')')
		builder.WriteRune('\n')

		gologger.Printf("%s", builder.String())
		builder.Reset()
	}
}

// fmtDuration formats the duration for the time elapsed
func fmtDuration(d time.Duration) string {
	d = d.Round(time.Second)
	h := d / time.Hour
	d -= h * time.Hour
	m := d / time.Minute
	d -= m * time.Minute
	s := d / time.Second
	return fmt.Sprintf("%d:%02d:%02d", h, m, s)
}

// Stop stops the progress bar execution
func (p *Progress) Stop() {
	_ = p.stats.Stop()
}