package client

import (
	"fmt"
	"github.com/mitchellh/mapstructure"
	"github.com/nsf/termbox-go"
	"github.com/pkg/errors"
	"github.com/zrepl/zrepl/config"
	"github.com/zrepl/zrepl/daemon"
	"github.com/zrepl/zrepl/replication"
	"github.com/zrepl/zrepl/replication/fsrep"
	"sort"
	"sync"
	"time"
)

type tui struct {
	x, y   int
	indent int

	lock   sync.Mutex //For report and error
	report map[string]interface{}
	err    error
}

func newTui() tui {
	return tui{}
}

func (t *tui) moveCursor(x, y int) {
	t.x += x
	t.y += y
}

func (t *tui) moveLine(dl int, col int) {
	t.y += dl
	t.x = t.indent*4 + col
}

func (t *tui) write(text string) {
	for _, c := range text {
		termbox.SetCell(t.x, t.y, c, termbox.ColorDefault, termbox.ColorDefault)
		t.x += 1
	}
}

func (t *tui) printf(text string, a ...interface{}) {
	t.write(fmt.Sprintf(text, a...))
}

func (t *tui) newline() {
	t.moveLine(1, 0)
}

func (t *tui) setIndent(indent int) {
	t.indent = indent
	t.moveLine(0, 0)
}

func (t *tui) addIndent(indent int) {
	t.indent += indent
	t.moveLine(0, 0)
}

func RunStatus(config *config.Config, args []string) error {
	httpc, err := controlHttpClient(config.Global.Control.SockPath)
	if err != nil {
		return err
	}

	t := newTui()
	t.lock.Lock()
	t.err = errors.New("Got no report yet")
	t.lock.Unlock()

	err = termbox.Init()
	if err != nil {
		return err
	}
	defer termbox.Close()

	update := func() {
		m := make(map[string]interface{})

		err2 := jsonRequestResponse(httpc, daemon.ControlJobEndpointStatus,
			struct{}{},
			&m,
		)

		t.lock.Lock()
		t.err = err2
		t.report = m
		t.lock.Unlock()
		t.draw()
	}
	update()

	ticker := time.NewTicker(500 * time.Millisecond)
	defer ticker.Stop()
	go func() {
		for _ = range ticker.C {
			update()
		}
	}()

	termbox.HideCursor()
	termbox.Clear(termbox.ColorDefault, termbox.ColorDefault)

loop:
	for {
		switch ev := termbox.PollEvent(); ev.Type {
		case termbox.EventKey:
			switch ev.Key {
			case termbox.KeyEsc:
				break loop
			case termbox.KeyCtrlC:
				break loop
			}
		case termbox.EventResize:
			t.draw()
		}
	}

	return nil

}

func (t *tui) draw() {
	t.lock.Lock()
	defer t.lock.Unlock()

	termbox.Clear(termbox.ColorDefault, termbox.ColorDefault)
	t.x = 0
	t.y = 0
	t.indent = 0

	if t.err != nil {
		t.write(t.err.Error())
	} else {
		//Iterate over map in alphabetical order
		keys := make([]string, len(t.report))
		i := 0
		for k, _ := range t.report {
			keys[i] = k
			i++
		}
		sort.Strings(keys)

		for _, k := range keys {
			v := t.report[k]
			if len(k) == 0 || k[0] == '_' { //Internal job
				continue
			}
			t.setIndent(0)

			t.printf("Job: %s", k)
			t.setIndent(1)
			t.newline()

			if v == nil {
				t.printf("No report generated yet")
				t.newline()
				continue
			}
			rep := replication.Report{}
			err := mapstructure.Decode(v, &rep)
			if err != nil {
				t.printf("Failed to decode report: %s", err.Error())
				t.newline()
				continue
			}


			all := make([]*fsrep.Report, 0, len(rep.Completed)+len(rep.Pending) + 1)
			all = append(all, rep.Completed...)
			all = append(all, rep.Pending...)
			if rep.Active != nil {
				all = append(all, rep.Active)
			}
			sort.Slice(all, func(i, j int) bool {
				return all[i].Filesystem < all[j].Filesystem
			})

			t.printf("Status:  %s", rep.Status)
			t.newline()
			if rep.Problem != "" {
				t.printf("Problem: %s", rep.Problem)
				t.newline()
			}
			{ // Progress: [---------------]
				sumUpFSRep := func(rep *fsrep.Report) (transferred, total int64) {
					for _, s := range rep.Pending {
						transferred += s.Bytes
						total  += s.ExpectedBytes
					}
					for _, s := range rep.Completed {
						transferred += s.Bytes
						total += s.ExpectedBytes
					}
					return
				}
				var transferred, total int64
				for _, fs := range all {
					fstx, fstotal := sumUpFSRep(fs)
					transferred += fstx
					total += fstotal
				}
				t.write("Progress: ")
				t.drawBar(80, transferred, total)
				t.write(fmt.Sprintf(" %s / %s", ByteCountBinary(transferred), ByteCountBinary(total)))
				t.newline()
			}

			var maxFSLen int
			for _, fs := range all {
				if len(fs.Filesystem) > maxFSLen {
					maxFSLen = len(fs.Filesystem)
				}
			}
			for _, fs := range all {
				printFilesystemStatus(fs, t, fs == rep.Active, maxFSLen)
			}
		}
	}
	termbox.Flush()
}

const snapshotIndent = 1
func calculateMaxFSLength(all []*fsrep.Report) (maxFS, maxStatus int) {
	for _, e := range all {
		if len(e.Filesystem) > maxFS {
			maxFS = len(e.Filesystem)
		}
		all2 := make([]*fsrep.StepReport, 0, len(e.Pending) + len(e.Completed))
		all2 = append(all2, e.Pending...)
		all2 = append(all2, e.Completed...)
		for _, e2 := range all2 {
			elen := len(e2.Problem) + len(e2.From) + len(e2.To) + 60 // random spacing, units, labels, etc
			if elen > maxStatus {
				maxStatus = elen
			}
		}
	}
	return
}

func times(str string, n int) (out string) {
	for i := 0; i < n; i++ {
		out += str
	}
	return
}

func rightPad(str string, length int, pad string) string {
	if len(str) > length {
		return str[:length]
	}
	return str + times(pad, length-len(str))
}


func leftPad(str string, length int, pad string) string {
	if len(str) > length {
		return str[len(str)-length:]
	}
	return times(pad, length-len(str)) + str
}

func (t *tui) drawBar(length int, bytes, totalBytes int64) {
	var completedLength int
	if totalBytes > 0 {
		completedLength = int(int64(length) * bytes / totalBytes)
		if completedLength > length {
			completedLength = length
		}
	} else if totalBytes == bytes {
		completedLength = length
	}

	t.write("[")
	t.write(times("=", completedLength))
	t.write(">")
	t.write(times("-", length-completedLength))
	t.write("]")
}

func StringStepState(s fsrep.StepState) string {
	switch s {
	case fsrep.StepReplicationReady: return "Ready"
	case fsrep.StepReplicationRetry: return "Retry"
	case fsrep.StepMarkReplicatedReady: return "MarkReady"
	case fsrep.StepMarkReplicatedRetry: return "MarkRetry"
	case fsrep.StepPermanentError: return "PermanentError"
	case fsrep.StepCompleted: return "Completed"
	default:
		return fmt.Sprintf("UNKNOWN %d", s)
	}
}

func filesystemStatusString(rep *fsrep.Report, active bool, fsWidth int) (line string, bytes, totalBytes int64) {
	bytes = int64(0)
	totalBytes = int64(0)
	for _, s := range rep.Pending {
		bytes += s.Bytes
		totalBytes += s.ExpectedBytes
	}
	for _, s := range rep.Completed {
		bytes += s.Bytes
		totalBytes += s.ExpectedBytes
	}

	next := ""
	if rep.Problem != "" {
		next = " problem: " + rep.Problem
	} else if len(rep.Pending) > 0 {
		if rep.Pending[0].From != "" {
			next = fmt.Sprintf("next: %s => %s", rep.Pending[0].From, rep.Pending[0].To)
		} else {
			next = fmt.Sprintf("next: %s (full)", rep.Pending[0].To)
		}
	}
	status := fmt.Sprintf("%s (step %d/%d, %s/%s)%s",
		rep.Status,
		len(rep.Completed), len(rep.Pending) + len(rep.Completed),
		ByteCountBinary(bytes), ByteCountBinary(totalBytes),
		next,
	)
	activeIndicator := " "
	if active {
		activeIndicator = "*"
	}
	line = fmt.Sprintf("%s %s %s",
		activeIndicator,
		rightPad(rep.Filesystem, fsWidth, " "),
		status)
	return line, bytes, totalBytes
}

func printFilesystemStatus(rep *fsrep.Report, t *tui, active bool, maxFS int) {
	totalStatus, _, _ := filesystemStatusString(rep, active, maxFS)
	t.write(totalStatus)
	t.newline()
}

func ByteCountBinary(b int64) string {
	const unit = 1024
	if b < unit {
		return fmt.Sprintf("%d B", b)
	}
	div, exp := int64(unit), 0
	for n := b / unit; n >= unit; n /= unit {
		div *= unit
		exp++
	}
	return fmt.Sprintf("%.1f %ciB", float64(b)/float64(div), "KMGTPE"[exp])
}