package progress

import (
	"context"
	"fmt"
	"io"
	"strings"
	"sync"
	"time"

	"github.com/buger/goterm"
	"github.com/morikuni/aec"
)

type ttyWriter struct {
	out      io.Writer
	events   map[string]Event
	eventIDs []string
	repeated bool
	numLines int
	done     chan bool
	mtx      *sync.RWMutex
}

func (w *ttyWriter) Start(ctx context.Context) error {
	ticker := time.NewTicker(100 * time.Millisecond)

	for {
		select {
		case <-ctx.Done():
			w.print()
			return ctx.Err()
		case <-w.done:
			w.print()
			return nil
		case <-ticker.C:
			w.print()
		}
	}
}

func (w *ttyWriter) Stop() {
	w.done <- true
}

func (w *ttyWriter) Event(e Event) {
	w.mtx.Lock()
	defer w.mtx.Unlock()
	if !contains(w.eventIDs, e.ID) {
		w.eventIDs = append(w.eventIDs, e.ID)
	}
	if _, ok := w.events[e.ID]; ok {
		event := w.events[e.ID]
		if event.Status != Done && e.Status == Done {
			event.stop()
		}
		event.Status = e.Status
		event.Text = e.Text
		event.StatusText = e.StatusText
		w.events[e.ID] = event
	} else {
		e.startTime = time.Now()
		e.spinner = newSpinner()
		w.events[e.ID] = e
	}
}

func (w *ttyWriter) print() {
	w.mtx.Lock()
	defer w.mtx.Unlock()
	if len(w.eventIDs) == 0 {
		return
	}
	terminalWidth := goterm.Width()
	b := aec.EmptyBuilder
	for i := 0; i <= w.numLines; i++ {
		b = b.Up(1)
	}
	if !w.repeated {
		b = b.Down(1)
	}
	w.repeated = true
	fmt.Fprint(w.out, b.Column(0).ANSI)

	// Hide the cursor while we are printing
	fmt.Fprint(w.out, aec.Hide)
	defer fmt.Fprint(w.out, aec.Show)

	firstLine := fmt.Sprintf("[+] Running %d/%d", numDone(w.events), w.numLines)
	if w.numLines != 0 && numDone(w.events) == w.numLines {
		firstLine = aec.Apply(firstLine, aec.BlueF)
	}
	fmt.Fprintln(w.out, firstLine)

	var statusPadding int
	for _, v := range w.eventIDs {
		l := len(fmt.Sprintf("%s %s", w.events[v].ID, w.events[v].Text))
		if statusPadding < l {
			statusPadding = l
		}
	}

	numLines := 0
	for _, v := range w.eventIDs {
		line := lineText(w.events[v], terminalWidth, statusPadding)
		// nolint: errcheck
		fmt.Fprint(w.out, line)
		numLines++
	}

	w.numLines = numLines
}

func lineText(event Event, terminalWidth, statusPadding int) string {
	endTime := time.Now()
	if event.Status != Working {
		endTime = event.endTime
	}

	elapsed := endTime.Sub(event.startTime).Seconds()

	textLen := len(fmt.Sprintf("%s %s", event.ID, event.Text))
	padding := statusPadding - textLen
	if padding < 0 {
		padding = 0
	}
	text := fmt.Sprintf(" %s %s %s%s %s",
		event.spinner.String(),
		event.ID,
		event.Text,
		strings.Repeat(" ", padding),
		event.StatusText,
	)
	timer := fmt.Sprintf("%.1fs\n", elapsed)
	o := align(text, timer, terminalWidth)

	color := aec.WhiteF
	if event.Status == Done {
		color = aec.BlueF
	}
	if event.Status == Error {
		color = aec.RedF
	}

	return aec.Apply(o, color)
}

func numDone(events map[string]Event) int {
	i := 0
	for _, e := range events {
		if e.Status == Done {
			i++
		}
	}
	return i
}

func align(l, r string, w int) string {
	return fmt.Sprintf("%-[2]*[1]s %[3]s", l, w-len(r)-1, r)
}

func contains(ar []string, needle string) bool {
	for _, v := range ar {
		if needle == v {
			return true
		}
	}
	return false
}