package pages

import (
	"context"
	"fmt"
	"math"
	"sync"
	"sync/atomic"
	"time"

	"gitea.unprism.ru/KRBL/mpu/mpu"
	"gitea.unprism.ru/KRBL/sim-modem/api/modem/gps"
	"gitea.unprism.ru/yotia/display-test/components"
	"gitea.unprism.ru/yotia/display-test/drawer"
)

/*
Status page has status line at the top and three lines with primary data below.
Status line shows time and signal and service icon at the right corner.

Main space can show several screens:
1) GPS
	GPS coordinates
2) System state
	temepature
	speed
	may be amount of cameras

Other pages can show for ex important logs.
*/

const (
	timeLayout = "01.09.06 15:04:05"

	screenN             = 2
	screenChangeTimeout = 6 * time.Second
)

type statusPage struct {
	drawer drawer.Drawer // Drawer with dysplay

	// Status data
	st systemStatus

	timeShift time.Duration

	// Visual components
	line0 components.Text
	line1 components.Text
	line2 components.Text
	line3 components.Text
	// Layout values
	signalX  int
	serviceX int
	// Current screen(index) (default - 0)
	curScreen atomic.Int32

	// Threads sync
	ctx    context.Context
	cancel context.CancelFunc
	wg     sync.WaitGroup
}

// Only functions that control content of page
type StatusPageContent interface {
	SystemStatusSetter
	SetTimeShift(shift time.Duration)
}

type StatusPage interface {
	Page
	StatusPageContent
}

func NewStatusPage(d drawer.Drawer) (StatusPage, error) {
	// Check display
	if err := d.GetDisplay().IsReady(); err != nil {
		return nil, fmt.Errorf("display is ready: %w", err)
	}

	// Create visual components
	line0, err := components.NewText(d, 0, drawer.LineH*0)
	if err != nil {
		return nil, fmt.Errorf("create line0: %w", err)
	}
	line1, err := components.NewText(d, 0, drawer.LineH*1)
	if err != nil {
		return nil, fmt.Errorf("create line1: %w", err)
	}
	line2, err := components.NewText(d, 0, drawer.LineH*2)
	if err != nil {
		return nil, fmt.Errorf("create line2: %w", err)
	}
	line3, err := components.NewText(d, 0, drawer.LineH*3)
	if err != nil {
		return nil, fmt.Errorf("create line3: %w", err)
	}

	// Calculate signal and service glyphs' pos
	signalX := d.W() - drawer.CommonGlyphs[drawer.SignalStatusGlyphI].W - drawer.CommonGlyphs[drawer.ServiceStatusGlyphI].W - drawer.CharGap
	serviceX := d.W() - drawer.CommonGlyphs[drawer.ServiceStatusGlyphI].W

	return &statusPage{
		drawer: d,

		line0: line0,
		line1: line1,
		line2: line2,
		line3: line3,

		signalX:  signalX,
		serviceX: serviceX,
	}, nil
}

func (p *statusPage) Activate() {
	// Draw
	p.drawer.Clear()

	p.SetRssi(0)
	p.SetService("NO SERVICE")

	// Setup threads
	p.ctx, p.cancel = context.WithCancel(context.Background())
	go p.timeUpdateLoop()
	go p.screenChangeLoop()
}

func (p *statusPage) Diactivate() {
	// Stop all support threads
	p.cancel()
	p.wg.Wait()
}

func (p *statusPage) SetTimeShift(shift time.Duration) {
	p.st.mutex.Lock()
	defer p.st.mutex.Unlock()

	p.timeShift = shift
}

func (p *statusPage) SetGps(newData gps.Data) {
	p.st.mutex.Lock()
	p.st.gpsData = newData
	p.st.mutex.Unlock()

	if p.curScreen.Load() == 0 { // Draw only on first screen
		p.drawCoords(&newData)
	}
}

func (p *statusPage) SetMpu(newData mpu.Data) {
	p.st.mutex.Lock()
	p.st.mpuData = newData
	p.st.mutex.Unlock()

	if p.curScreen.Load() == 1 { // Draw only on second screen
		p.drawMpu(&newData)
	}
}

func (p *statusPage) SetRssi(rssi int) {
	// Save data
	p.st.mutex.Lock()
	p.st.rssi = rssi
	p.st.mutex.Unlock()

	// Draw
	p.drawRssi(rssi)
}

func (p *statusPage) SetService(svc string) {
	// Save data
	p.st.mutex.Lock()
	p.st.service = svc
	p.st.mutex.Unlock()

	// Draw
	p.drawService(svc)
}

func (p *statusPage) Close() (outErr error) {

	// TODO Not the best way...
	if err := p.line0.Close(); err != nil {
		outErr = fmt.Errorf("line 0 close: %w:", err)
	}
	if err := p.line1.Close(); err != nil {
		outErr = fmt.Errorf("line 1 close: %w:", err)
	}
	if err := p.line2.Close(); err != nil {
		outErr = fmt.Errorf("line 2 close: %w:", err)
	}
	if err := p.line3.Close(); err != nil {
		outErr = fmt.Errorf("line 3 close: %w:", err)
	}
	return
}

func getSignalStrength(rssi int) int {
	// Signal strength clasification (from google):
	// 0 - no signal        -110 to ...
	// 1 - poor signal       -90 to -110
	// 2 - fair signal       -70 to -90
	// 3 - good signal       -50 to -70
	// 4 - excelent signal   ... to -50

	// Description from "sim-modem/api/modem/utils/signal.go"
	// 0          -113 dBm or less
	// 1          -111 dBm
	// 2...30     -109... -53 dBm
	// 31         -51 dBm or greater
	// 99         not known or not detectable
	// 100        -116 dBm or less
	// 101        -115 dBm
	// 102…191    -114... -26dBm
	// 191        -25 dBm or greater
	// 199        not known or not detectable
	// 100…199    expand to TDSCDMA, indicate RSCPreceived

	// Cut certain cases
	switch rssi {
	case 99, 199: // not known or not detectable
		return 0
	case 0, 1, 100, 101: // no signal
		return 0
	case 31, 191: // Excelent
		return 4
	}

	// Ranged values
	if rssi >= 2 && rssi <= 30 {
		// it is in -109...-53 dBm
		// Simplified interpolation from 2..30 to -109...-53 and then to 0...4
		return int((float64(rssi)*2-3)/20) + 1
	}
	if rssi >= 102 && rssi <= 191 {
		// it is in -114...-26 dBm
		// Simplified interpolation from 2..30 to -114...-26 and then to 0...4
		return min(int((float64(rssi-102)+15)/20), 4)
	}

	return 0 // Invalid value
}

func getServiceStrength(service string) int {
	// Service clasification by speed:
	// 0 - no service - "NO SERVICE"
	// 1 - 1G - do not use
	// 2 - 2G - "GSM"
	// 3 - 3G - "WCDMA"
	// 4 - 4G - "LTE", "TDS"

	switch service {
	case "NO SERVICE":
		return 0
	case "GSM":
		return 2
	case "WCDMA":
		return 3
	case "LTE", "TDS":
		return 4
	}

	return 0 // Invalid value
}

// Update time in top line
func (p *statusPage) timeUpdateLoop() {
	p.wg.Add(1)

	// Because ticker do not send signal immediately
	p.line0.SetStr(time.Now().Add(p.timeShift).Format(timeLayout))

	ticker := time.NewTicker(time.Second)
	for {
		select {
		case <-p.ctx.Done():
			ticker.Stop()
			p.wg.Done()
			return
		case now := <-ticker.C:
			p.line0.SetStr(now.Add(p.timeShift).Format(timeLayout))
		}
	}
}

func (p *statusPage) screenChangeLoop() {
	p.wg.Add(1)

	// Because ticker do not send signal immediately
	ticker := time.NewTicker(screenChangeTimeout)
	for {
		select {
		case <-p.ctx.Done():
			ticker.Stop()
			p.wg.Done()
			return
		case <-ticker.C:
			p.changeScreen()
		}
	}
}

func (p *statusPage) changeScreen() {
	scr := p.curScreen.Load()
	scr = (scr + 1) % screenN
	p.curScreen.Store(scr)
	p.drawScreen(int(scr))
}

///////////////////// Draw functions /////////////////////

// Draw functions get draw data as arguments because otherwise they have to get it using mutex
// Moreover they will lock it second time

func (p *statusPage) drawRssi(rssi int) {
	ss := getSignalStrength(rssi) // Signal strength in [0; 4] range
	p.drawer.CopyImg(p.signalX, 0, drawer.CommonGlyphs[drawer.SignalStatusGlyphI+ss])
	p.drawer.GetDisplay().FlushByMask(p.drawer.GetDisplay().GetFlushMaskBit(1, 0))
}

func (p *statusPage) drawService(svc string) {
	ss := getServiceStrength(svc) // Service strength in [0; 4] range
	p.drawer.CopyImg(p.serviceX, 0, drawer.CommonGlyphs[drawer.ServiceStatusGlyphI+ss])
	p.drawer.GetDisplay().FlushByMask(p.drawer.GetDisplay().GetFlushMaskBit(1, 0))
}

func (p *statusPage) drawCoords(data *gps.Data) {
	// Langitude, longitude store format: ddmm.mmmmmm, dddmm.mmmmmm
	// Latitude and longitude layout:
	//  DD° MM.MMM' N
	// DDD° MM.MMM' W
	latStr := fmt.Sprintf("   %02d°%06.3f' %s", int(p.st.gpsData.Latitude)/100, math.Mod(p.st.gpsData.Latitude, 100), p.st.gpsData.LatitudeIndicator)
	p.line2.SetStr(latStr)
	logStr := fmt.Sprintf("  %03d°%06.3f' %s", int(p.st.gpsData.Longitude)/100, math.Mod(p.st.gpsData.Longitude, 100), p.st.gpsData.LongitudeIndicator)
	p.line3.SetStr(logStr)
}

func (p *statusPage) drawMpu(data *mpu.Data) {
	// Layout:
	// temp    ttt.ttC

	tempStr := fmt.Sprintf("temperature %06.3fC", data.TempData)
	p.line2.SetStr(tempStr)
}

// Draw main part depends on what current screen is active
func (p *statusPage) drawScreen(screen int) {
	// Clear
	//p.drawer.FillBar(0, drawer.LineH, p.drawer.W(), p.drawer.H()-drawer.LineH, 0)
	//p.drawer.GetDisplay().FlushByMask(0b01110111)
	p.line1.SetStr("")
	p.line2.SetStr("")
	p.line3.SetStr("")
	switch screen {
	case 0:
		p.st.mutex.Lock()
		gpsData := &p.st.gpsData
		p.st.mutex.Unlock()
		p.drawCoords(gpsData)
	case 1:
		p.st.mutex.Lock()
		mpuData := &p.st.mpuData
		p.st.mutex.Unlock()
		p.drawMpu(mpuData)
		p.line1.SetStr("47 cameras connected")
		p.line3.SetStr("some other info...")
	}
}