// "Rail trail"? "Trail rail"!

/* fmt library v0.2.2 */
let fmt = {
  icon_alt : "\0\x08\x1a\1\x00\x00\x00\x20\x30\x78\x7C\xFE\xFF\x00\xC3\xE7\xFF\xDB\xC3\xC3\xC3\xC3\x00\x00\x00\x00\x00\x00\x00\x00",
  icon_m : "\0\x08\x1a\1\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xC3\xE7\xFF\xDB\xC3\xC3\xC3\xC3\x00\x00\x00\x00\x00\x00\x00\x00",
  icon_km : "\0\x08\x1a\1\xC3\xC6\xCC\xD8\xF0\xD8\xCC\xC6\xC3\x00\xC3\xE7\xFF\xDB\xC3\xC3\xC3\xC3\x00\x00\x00\x00\x00\x00\x00\x00",
  icon_kph : "\0\x08\x1a\1\xC3\xC6\xCC\xD8\xF0\xD8\xCC\xC6\xC3\x00\xC3\xE7\xFF\xDB\xC3\xC3\xC3\xC3\x00\xFF\x00\xC3\xC3\xFF\xC3\xC3",
  icon_c : "\0\x08\x1a\1\x00\x00\x60\x90\x90\x60\x00\x7F\xFF\xC0\xC0\xC0\xC0\xC0\xFF\x7F\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
  icon_hpa : "\x00\x08\x16\x01\x00\x80\xb0\xc8\x88\x88\x88\x00\xf0\x88\x84\x84\x88\xf0\x80\x8c\x92\x22\x25\x19\x00\x00",
  icon_9 : "\x00\x08\x16\x01\x00\x00\x00\x00\x38\x44\x44\x4c\x34\x04\x04\x38\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
  icon_10 : "\x00\x08\x16\x01\x00\x08\x18\x28\x08\x08\x08\x00\x00\x18\x24\x24\x24\x24\x18\x00\x00\x00\x00\x00\x00\x00",

  /* 0 .. DD.ddddd
     1 .. DD MM.mmm'
     2 .. DD MM'ss"
  */
  geo_mode : 1,

  init: function() {},
  fmtDist: function(km) {
    if (km >= 1.0) return km.toFixed(1) + this.icon_km;
    return (km*1000).toFixed(0) + this.icon_m;
  },
  fmtSteps: function(n) { return this.fmtDist(0.001 * 0.719 * n); },
  fmtAlt: function(m) { return m.toFixed(0) + this.icon_alt; },
  fmtTemp: function(c) { return c.toFixed(1) + this.icon_c; },
  fmtPress: function(p) { 
    if (p < 900 || p > 1100)
      return p.toFixed(0) + this.icon_hpa; 
    if (p < 1000) {
      p -= 900;
      return this.icon_9 + this.add0(p.toFixed(0)) + this.icon_hpa;
    }
    p -= 1000;
    return this.icon_10 + this.add0(p.toFixed(0)) + this.icon_hpa;
  },
  draw_dot : 1,
  add0: function(i) {
    if (i > 9) {
      return ""+i;
    } else {
      return "0"+i;
    }
  },
  fmtTOD: function(now) {
    this.draw_dot = !this.draw_dot;
    let dot = ":";
    if (!this.draw_dot)
      dot = ".";
    return now.getHours() + dot + this.add0(now.getMinutes());
  },
  fmtNow: function() { return this.fmtTOD(new Date()); },
  fmtTimeDiff: function(d) {
    if (d < 180)
      return ""+d.toFixed(0);
    d = d/60;
    return ""+d.toFixed(0)+"m";
  },
  fmtAngle: function(x) {
    switch (this.geo_mode) {
    case 0:
      return "" + x;
    case 1: {
      let d = Math.floor(x);
      let m = x - d;
      m = m*60;
      return "" + d + " " + m.toFixed(3) + "'";
    }
    case 2: {
      let d = Math.floor(x);
      let m = x - d;
      m = m*60;
      let mf = Math.floor(m);
      let s = m - mf;
      s = s*60;
      return "" + d + " " + mf + "'" + s.toFixed(0) + '"';
    }
    }
    return "bad mode?";
  },
  fmtPos: function(pos) {
    let x = pos.lat;
    let c = "N";
    if (x<0) {
      c = "S";
      x = -x;
    }
    let s = c+this.fmtAngle(x) + "\n";
    c = "E";
    if (x<0) {
      c = "W";
      x = -x;
    }
    return s + c + this.fmtAngle(x);
  },
  fmtFix: function(fix, t) {
    if (fix && fix.fix && fix.lat) {
      return this.fmtSpeed(fix.speed) + " " +
        this.fmtAlt(fix.alt);
    } else {
      return "N/FIX " + this.fmtTimeDiff(t);
    }
  },
  fmtSpeed: function(kph) {
    return kph.toFixed(1) + this.icon_kph;
  },
  radians: function(a) { return a*Math.PI/180; },
  degrees: function(a) { return a*180/Math.PI; },
  // distance between 2 lat and lons, in meters, Mean Earth Radius = 6371km
  // https://www.movable-type.co.uk/scripts/latlong.html
  // (Equirectangular approximation)
  // returns value in meters
  distance: function(a,b) {
    var x = this.radians(b.lon-a.lon) * Math.cos(this.radians((a.lat+b.lat)/2));
    var y = this.radians(b.lat-a.lat);
    return Math.sqrt(x*x + y*y) * 6371000;
  },
  // thanks to waypointer
  bearing: function(a,b) {
    var delta = this.radians(b.lon-a.lon);
    var alat = this.radians(a.lat);
    var blat = this.radians(b.lat);
    var y = Math.sin(delta) * Math.cos(blat);
    var x = Math.cos(alat) * Math.sin(blat) -
        Math.sin(alat)*Math.cos(blat)*Math.cos(delta);
    return Math.round(this.degrees(Math.atan2(y, x)));
  },
};

/* gps library v0.1.3 */
let gps = {
  emulator: -1,
  init: function(x) {
    this.emulator = (process.env.BOARD=="EMSCRIPTEN" 
                     || process.env.BOARD=="EMSCRIPTEN2")?1:0;
  },
  state: {},
  on_gps: function(f) {
    let fix = this.getGPSFix();
    f(fix);

    /*
      "lat": number,      // Latitude in degrees
      "lon": number,      // Longitude in degrees
      "alt": number,      // altitude in M
      "speed": number,    // Speed in kph
      "course": number,   // Course in degrees
      "time": Date,       // Current Time (or undefined if not known)
      "satellites": 7,    // Number of satellites
      "fix": 1            // NMEA Fix state - 0 is no fix
      "hdop": number,     // Horizontal Dilution of Precision
    */
    this.state.timeout = setTimeout(this.on_gps, 1000, f);
  },
  off_gps: function() {
    clearTimeout(this.state.timeout);
  },
  getGPSFix: function() {
    if (!this.emulator)
      return Bangle.getGPSFix();
    let fix = {};
    fix.fix = 1;
    fix.lat = 50.010507;
    fix.lon = 14.765840-(getTime()-this.gps_start) / 10000; /* Go West! */
    fix.alt = 200;
    fix.speed = 5;
    fix.course = 30;
    fix.time = Date();
    fix.satellites = 5;
    fix.hdop = 12;
    return fix;
  },
  gps_start : -1,
  start_gps: function() {
    Bangle.setGPSPower(1, "libgps");
    this.gps_start = getTime();
  },
  stop_gps: function() {
    Bangle.setGPSPower(0, "libgps");
  },
};

/* ui library 0.2.0 -- see skyspy */
//Bangle.on("drag", (b) => ui.touchHandler(b));
let ui = {
  display: 0,
  numScreens: 2,
  name: ".oO busy",
  screens: [ "Screen 1", "Screen 2", "Screen 3", "Screen 4", "Screen 5", "Screen 6" ],
  help: [ "F1", "F2", "<", ">" ],
  clear: function() {
    g.reset()
      .setColor(g.theme.bg)
      .fillRect(0, this.wi, this.w, this.y2)
      .setColor(g.theme.fg);
  },
  draw: function(screen) {},
  drawMsg: function(msg) {
    this.clear();
    g.setFont("Vector", 35)
      .drawString(msg, 5, 30)
      .flip();
  },
  drawBusy: function() {
    this.clear();
    g.setFont("Vector", 35);
    let help = this.help;
    g.setFontAlign(-1, -1).drawString(help[0], 0, this.wi);
    g.setFontAlign(1, -1).drawString(help[1], this.w, this.wi);
    g.setFontAlign(-1, 1).drawString(help[2], 0, this.h+this.wi);
    g.setFontAlign(1, 1).drawString(help[3], this.w, this.h+this.wi);
    g.setFontAlign(0, 0)
      .drawString(this.name, this.w/2, this.h/2);
    g.reset();
  },
  drawScreen: function() {
    this.drawMsg(this.screens[this.display]);
    let t1 = getTime();
    this.draw();
    let t = getTime() - t1;
    if (t > 30) {
      print("Draw took", t, "msec");
    }
  },
  nextScreen: function() {
    print("nextS");
    this.display = this.display + 1;
    if (this.display == this.numScreens)
      this.display = 0;
    this.drawScreen();
  },
  prevScreen: function() {
    print("prevS");
    this.display = this.display - 1;
    if (this.display < 0)
      this.display = this.numScreens - 1;
    this.drawScreen();
  },
  onSwipe: function(dir) {
    this.nextScreen();
  },
  wi: 24,
  y2: 176,
  h: 152,
  w: 176,
  last_b: 0,
  topLeft: function() { this.drawMsg("Unimpl"); },
  topRight: function() { this.drawMsg("Unimpl"); },
  touchHandler: function(d) {
    let x = Math.floor(d.x);
    let y = Math.floor(d.y);
    
    if (d.b != 1 || this.last_b != 0) {
      this.last_b = d.b;
      return;
    }
    
    print("touch", x, y, this.h, this.w);

    if ((x<this.w/2) && (y<this.y2/2))
      this.topLeft();
    if ((x>this.w/2) && (y<this.y2/2))
      this.topRight();
    if ((x<this.w/2) && (y>this.y2/2)) {
      print("prev");
      this.prevScreen();
    }
    if ((x>this.w/2) && (y>this.y2/2)) {
      print("next");
      this.nextScreen();
    }
  },
  init: function() {
    this.h = this.y2 - this.wi;
    this.drawBusy();
  },
  /* radial angle -- convert 0..1 to 0..2pi */
  radA: function(p) { return p*(Math.PI*2); },
  /* radial distance -- convert 0..1 to something that fits on screen */
  radD: function(d) { return d*(ui.h/2); },

  /* given angle/distance, get X coordinate */
  radX: function(p, d) {
    let a = this.radA(p);
    return this.w/2 + Math.sin(a)*this.radD(d);
  },
  /* given angle/distance, get Y coordinate */
  radY: function(p, d) {
    let a = this.radA(p);
    return this.h/2 - Math.cos(a)*this.radD(d) + this.wi;
  },
  radLine: function(a1, d1, a2, d2) {
    g.drawLine(this.radX(a1, d1), this.radY(a1, d1), this.radX(a2, d2), this.radY(a2, d2));
  },
  radCircle: function(d) {
    g.drawCircle(this.radX(0, 0), this.radY(0, 0), this.radD(d));
    if (1)
      return;
    let step = 0.05;
    for (let i = 0; i < 1; i += 0.05) {
      this.radLine(i - step, d, i, d);
    }
  },
};

/* egt 0.0.3 */
let egt = {
  init: function() {
  },
  removeCRLF: function(s) {
    let end = s.length;
    while (end > 0) {
        let ch = s[end - 1];
        if (ch === '\n' || ch === '\r') {
            end--;
        } else {
            break;
        }
    }
    return s.slice(0, end);
  },

  parse: function(l) {
    l = this.removeCRLF(l);
    let r = {};
    let s = l.split(' ');

    if (s === undefined)
      return r;

    if (s[1] === undefined)
      return r;

    if (s[1].split('=')[1] === undefined) {
      r.lat = 1 * s[0];
      r.lon = 1 * s[1];
      if (!r.lat || !r.lon) {
        print("Parse error at ", l, "have (", s[0], s[1], ")");
      }
    }

    for (let fi of s) {
      let f = fi.split('=');
      if (f[0] == "utime") {
        r.utime = 1 * f[1];
      }
    }

    return r;
  },
};


/* zoom library v0.0.4 */
var zoom = {
  buf : 0,
  /* y coordinate is "strange" -- positive values go north */ 
  /* x1 -- left, x2 -- right of simulated canvas.
     we want x1 < x2, y1 < y2. */
  x1 : 0, x2 : 0, y1 : 0, y2 : 0, 
  /* screen size in pixels */
  ss : 176,
  /* size in pixels */
  init : function(size) {
    this.size = size;
    this.buf = Graphics.createArrayBuffer(size, size, 2, { msb: true });
  },
  clear : function() {
    this.buf.reset().clear();
  },
  /* Origin in lat/lon */
  origin : 0,
  geoNew : function(p, is) {
    this.clear();
    this.origin = p;
    let i = Bangle.project(p);
    this.x1 = i.x - is;
    this.x2 = i.x + is;
    this.y1 = i.y - is;
    this.y2 = i.y + is;
  },
  /* output: 0..1 */
  xrel : function(i)  {
    let r = {};
    r.x = ((i.x - this.x1) / (this.x2 - this.x1));
    r.y = ((i.y - this.y1) / (this.y2 - this.y1));
    return r;
  },
  /* input: meters, output: pixels in buf*/
  xform : function(p) {
    let r = this.xrel(p);
    r.x *= this.size;
    r.y *= -this.size;
    r.y += this.size;
    return r;
  },
  /* takes x, y with lat/lon m */
  geoLine : function(i1, i2) {
    this.drawLine(Bangle.project(i1), Bangle.project(i2));
  },
  /* takes x, y in m */
  drawLine : function(i1, i2) {
    let p1 = this.xform(i1);
    let p2 = this.xform(i2);
    //print("line", p1, p2);
    this.buf.drawLine(p1.x, p1.y, p2.x, p2.y);
  },
  geoPaint : function(i, head, z) {
    this.mPaint(Bangle.project(i), head, z);
  },
  /* vx, vy: viewpoint in meters,
     head: which heading to display as up,
     zoom: how many meters from center of screen to edge */
  mPaint : function(v, head, z) {
    let sh = this.xrel(v);
    sh.x = sh.x - 0.5;
    sh.y = 0.5 - sh.y;
    let scale = ((this.y2-this.y1)/(z*2)) * this.ss/this.size;
    let dist = Math.sqrt(sh.x*sh.x + sh.y*sh.y) * this.ss * scale;
    let theta = Math.atan2(-sh.y, sh.x);
    let rad = (head / 360) * 2 * Math.PI;
    let ox = Math.sin(theta - rad + 1.5*Math.PI) * dist;
    let oy = Math.cos(theta - rad + 1.5*Math.PI) * dist;
    /*
    print("scale", scale);
    print("dist", dist);
    print("o", ox, oy);
    */
    
    /* drawimage... takes middle of the image, and rotates around it.
                ... in pixels
       scale is pixels to pixels */
    g.drawImage(zoom.buf, 176/2 + ox, 176/2 + oy,
                { rotate: rad,
                  scale: scale });
  }
};

function toCartesian(v) {
  const R = 6371; // Earth radius in km
  const latRad = v.lat * Math.PI / 180;
  const lonRad = v.lon * Math.PI / 180;

  const x = R * lonRad * Math.cos(latRad);
  const y = R * latRad;

  return { x, y };
}

function distSegment(x1, x2, xP) {
  // Translate geo to cartesian
  const p1 = toCartesian(x1);
  const p2 = toCartesian(x2);
  const p = toCartesian(xP);

  const dx = p2.x - p1.x;
  const dy = p2.y - p1.y;
  
  const div = (dx * dx + dy * dy);

  // Project point p to line defined by p1 / p2.
  let dot = 2;
  if (div)
    dot = ((p.x - p1.x) * dx + (p.y - p1.y) * dy) / div;

  // Compute closest point to projection
  let closestX, closestY;
  if (dot < 0) {
    closestX = p1.x;
    closestY = p1.y;
  } else if (dot > 1) {
    closestX = p2.x;
    closestY = p2.y;
  } else {
    closestX = p1.x + dot * dx;
    closestY = p1.y + dot * dy;
  }

  const distance = Math.sqrt((p.x - closestX) * (p.x - closestX) + (p.y - closestY) * (p.y - closestY));

  return distance * 1000;
}

function angleDifference(angle1, angle2) {
  // Compute the difference
  let difference = angle2 - angle1;

  // Normalize the difference to be within the range -180° to 180°
  while (difference > 180) difference -= 360;
  while (difference < -180) difference += 360;

  return difference;
}

/* Main code */

/* These are initialized by read() function, below */
var start = {}, destination = {}, num = 0, dist = 0;

/* pp .. Point, n .. filename, candy .. enable "eye candy" drawing */
function read(pp, n, candy) {
  let f = require("Storage").open(n+".st", "r");
  let l = f.readLine();
  let prev = 0;

  g.setColor(0, 0, 0);
  g.setFont("Vector", 31);
  
  while (l!==undefined) {
    l = ""+l;
    let p = egt.parse(l);
    if (p.lat) {
      if (prev) {
        dist += fmt.distance(prev, p);
        if (pp.g)
          paint(pp, prev, p, 1);
      } else {
        if (candy)
          zoom.geoNew(p, 3000);
        start = p;
        if (candy) {
        pp.lat = p.lat;
        pp.lon = p.lon;
        }
        /* FIXME: won't init destination */
        //return;
      }
      prev = p;
    }
    l = f.readLine();
    if (!(num % 30)) {
      g.clear();
      zoom.geoPaint(prev, 0, 2500);
      g.drawString(num + "\n" + fmt.fmtDist(dist / 1000) + "\n" + track_name, 3, 3);
      g.flip();
      print(num, "points");
      if (candy && !(num % 300)) {
        zoom.geoNew(prev, 3000);
      }
    }
    num++;
  }
  ui.drawMsg(num + "\n" + fmt.fmtDist(dist / 1000));
  destination = prev;
}

/* Find out start/stop points (and display some eye-candy) */
function time_read() {
  let n = track_name;
  ui.drawMsg("Converting");
  print("Converting...");
  to_storage(n);
  print("Running...");
  let v1 = getTime();
  let pp = {};
  pp.ppm = 0.0008 * 5; /* Pixels per meter */
  pp.course = 0;
  pp.x = 176/2;
  pp.y = 176/2;
  pp.g = zoom.buf;
  read(pp, n, 1);
  // { rotate: Math.PI / 4 + i/100, scale: 1-i/100 }

  let v2 = getTime();
  print("Read took", (v2-v1), "seconds");
  step_init();
  zoom.geoNew(start, 3000);
  print(num, "points", dist, "distance");
  setTimeout(step, 100);
}

/* Main code for displaying track */

var track_name = "", inf, point_num, track = [], track_points = 30, north = {}, point_drawn;

function step_init() {
  inf = require("Storage").open(track_name + ".st", "r");
  north = {};
  north.lat = 89.9;
  north.lon = 0;
  point_num = 0;
  point_drawn = 0;
  track = [];
  zoom.geoNew(start, 3000);
}

function load_next() {
  while (track.length < track_points) {
    let l = inf.readLine();
    if (l === undefined) {
      print("End of track");
      return 0;
    }
    let p = egt.parse(l);
    if (!p.lat) {
      print("No latitude?");
      continue;
    }
    p.point_num = point_num++;
    print("Loading ", p.point_num);
    track.push(p);
  }
  return 1;
}

function paint(pp, p1, p2, thick) {
  zoom.geoLine(p1, p2);
}

/* Paint points in window around current position */
function paint_all(pp) {
  let prev = 0;
  let mDist = 99999999999, m = 0;
  const fast = 0;
  let new_drawn = -1;

  g.setColor(1, 0, 0);
  for (let i = track.length-1; i > 1; i--) {
    let p = track[i];
    if (point_drawn >= p.point_num)
      break;
    prev = track[i-1];
    paint(pp, prev, p, 3);
    if (new_drawn == -1)
      new_drawn = p.point_num;
  }
  if (new_drawn != -1)
    point_drawn = new_drawn;
  for (let i = 1; i < track.length; i++) {
    let p = track[i];
    prev = track[i-1];
    if (!fast) {
      let d = distSegment(prev, p, pp);
      if (d < mDist) {
        mDist = d;
        m = i;
      } else if (mDist < 10 && d > 100)
        break;
    }
  }
  if (fast)
    return { quiet: 0, offtrack : 0 };
  print("Best segment was", m, "dist", mDist);
  /* If we are too far from ... */
  if (fmt.distance(track[m], zoom.origin) > 2500) {
    zoom.geoNew(track[m], 3000); // FIXME: this will flicker
    point_drawn = 0;
  }

  /* Estimate distance to next turn/intersection */
  let ahead = 0, a = fmt.bearing(track[m-1], track[m]), quiet = -1;
  for (let i = m+1; i < track.length; i++) {
    let a2 = fmt.bearing(track[i-1], track[i]);
    let ad = angleDifference(a, a2);
    if (Math.abs(ad) > 20) {
      if (quiet == -1)
        quiet = ahead + fmt.distance(pp, track[i-1]);
      print("...straight", ahead);
      a = a2;
      break;
    }
    ahead += fmt.distance(track[i-1], track[i]);
  }
  print("...see", ahead);
  return { quiet: quiet, offtrack: mDist };
}

function drop_last() {
    print("Dropping ", track[0].point_num);
    track.shift();
}

/* Display data for given position -- pp.
   Drop data that are more than 150 meters behind current position */
function step_to(pp, pass_all) {    
  if (0) {
    g.setColor(0.5, 0.5, 1);
    paint(pp, pp, destination, 1);
  
    g.setColor(1, 0.5, 0.5);
    paint(pp, pp, north, 1);
  }
  let quiet = paint_all(pp);
  while (distSegment(track[0], track[1], pp) > 150 &&
         track.length > 10) {
    drop_last();
  }
  return quiet;
}

var demo_mode = 0, zoom_mode = 0;

function step() {
  const fast = 0;
  let follow = 0;
  switch (ui.display) {
  case 0: follow = 1; break;
  case 1: break;
  case 2: follow = 1; break;
  }
  
  let v1 = getTime();
  g.reset().clear();

  let fix = gps.getGPSFix();
  let have_more = 1;
  if (follow)
    have_more = load_next();
  
  let pp = fix;
  pp.ppm = 0.08 * 3; /* Pixels per meter */
  pp.g = g;

  if (follow && (demo_mode || !fix.fix)) {
    let i = 2;
    pp.lat = track[i].lat;
    pp.lon = track[i].lon;
    pp.course = fmt.bearing(track[i], track[i+1]);
  }
  if (!follow && !fix.fix) {
    pp.lat = 50.010507;  /* FIXME */
    pp.lon = 14.765840;
    pp.course = 0;
  }

  let quiet = {};
  if (follow)
    quiet = step_to(pp, 1);
  let zoom_scale = 0;
  switch (zoom_mode) {
  case 0: zoom_scale = 500; break;
  case 1: zoom_scale = 1500; break;
  case 2: zoom_scale = 2500; break;
  }  
  switch (ui.display) {
  case 0: break;
  case 1: break;
  case 2:
    ui.drawMsg("Stats\n" + fmt.fmtDist(0 / 1000) + "\n" + point_num + "/" + num);
    zoom_scale = 0;
    break;
  }
  if (zoom_scale) {
    g.setColor(0, 0, 0);
    zoom.geoPaint(pp, -pp.course, zoom_scale);
  }
  
  if (zoom_scale) {
    /* Draw arrow representing current position */
    pp.x = ui.w/2;
    pp.y = ui.h*0.5;

    g.setColor(0, 0, 1);
    let sc = 2.5;
    g.drawPoly([ pp.x, pp.y, pp.x - 5*sc, pp.y + 12*sc, pp.x + 5*sc, pp.y + 12*sc ], true);
  }
  
  g.setColor(0, 0, 0);
  if (zoom_scale && !fast) {
    g.setFont("Vector", 31);
    g.setFontAlign(-1, -1);
    let msg = "\noff " + fmt.fmtDist(quiet.offtrack/1000);
    if (!have_more) {
      msg += "\nEnd!";
    }
    g.drawString(fmt.fmtFix(fix, getTime()-gps.gps_start) + msg, 3, 3);
  }
  if (zoom_scale && !fast) {
    g.setFont("Vector", 23);
    g.setColor(0, 0, 0);
    g.setFontAlign(-1, 1);
    g.drawString(fmt.fmtNow(), 3, ui.h);
    g.setFontAlign(1, 1);
    g.drawString(fmt.fmtDist(quiet.quiet/1000), ui.w-3, ui.h);
  }

  if (quiet < 200)
    Bangle.setLCDPower(1);

  if (demo_mode)
    drop_last();
  let v2 = getTime();
  print("Step took", (v2-v1), "seconds");
  setTimeout(step, 1000);
}

/* Recovery: If we get completely lost, we can do this.
   It works similar to main loop, but faster.
   It simply drop points until we are 400meters from the fix, then main code can take over.
*/
function recover() {
  ui.drawMsg("Recover...");
  step_init();
  let fix = gps.getGPSFix();
  let pp = fix;
  pp.ppm = 0.08 * 3; /* Pixels per meter */
  if (!fix.fix) {
    print("Can't recover with no fix\n");
    fix.lat = 50.010507;  /* FIXME */
    fix.lon = 14.765840;
  }
  load_next();
  while(1) {
    let d = distSegment(track[0], track[1], pp);
    if (d === undefined) {
      print("Distance wrong?");
    }
    print("Recover, d", d, track[0], track[1]);
    if (d < 400)
      break;
    track.shift();
    if (0)
      step_to(pp, 1);
    if (!load_next())
      break;
    if (!(point_num % 30))
      ui.drawMsg("Recover\n" + fmt.fmtDist(d / 1000) + "\n" + point_num + "/" + num + "\n" + track_name);
  }
}

/* Draw map around current position */
function draw_map() {
  ui.drawMsg("Draw...");
  let fix = gps.getGPSFix();
  if (!fix.fix) {
    print("Can't draw with no fix\n");
    fix.lat = 50.010507;  /* FIXME */
    fix.lon = 14.765840;
  }
  let pp = fix;
  pp.ppm = 0.008 * 5; /* Pixels per meter */
  pp.course = 0;
  pp.x = 176/2;
  pp.y = 176/2;
  pp.g = zoom.buf;
  let d = 0;
  step_init();  
  read(pp, track_name, 0);
  ui.drawMsg("Drawn\n" + fmt.fmtDist(d / 1000) + "\n" + point_num + "/" + num);
}

/* Convert "normal" file to storagefile... so that we can read lines from it */
function to_storage(n) {
  let f2 = require("Storage").open(n+".st", "w");
  let pos = 0;
  let size = 1024;
  while (1) {
    let d = require("Storage").read(n, pos, size);
    if (!d)
      break;
    f2.write(d);
    pos += size;
    print("Copy ", pos);
  }
}

fmt.init();
egt.init();
gps.init();
gps.start_gps();
zoom.init(176);

const st = require('Storage');

let l = /^[tr]\..*\.egt$/;
l = st.list(l, {sf:false});

print(l);

/* After user selected the track, we can switch to main interface */
function load_track(x) {
  ui.init();
  ui.numScreens = 3;
  ui.screens = [ "Follow", "Map", "Stats" ];

  Bangle.buzz(50, 1);
  ui.drawMsg("Loading\n"+x);
  track_name = x;
  time_read();

  Bangle.on("drag", (b) => ui.touchHandler(b));
  Bangle.setUI({
  mode : "custom",
  clock : 0
  });
  ui.topLeft = () => {
    switch (ui.display) {
    case 0:
    case 1:
        zoom_mode++;
        if (zoom_mode == 3)
          zoom_mode = 0;
        ui.drawMsg("Zoom\nmode\n" + zoom_mode);
        break;
    case 2: demo_mode = !demo_mode; 
        ui.drawMsg("Demo\nmode\n" + demo_mode);
        break;
    }
  }
  ui.topRight = () => {
    switch (ui.display) {
    case 0: ui.drawMsg("Recover"); recover(); break;
    case 1: ui.drawMsg("Draw map"); draw_map(); break;
    }
  };
}

/* Display menu with tracks. */
var menu = {
    "< Back" : Bangle.load
};
if (l.length==0) menu["No tracks"] = ()=>{};
else for (let id in l) {
    let i = id;
    menu[l[id]]=()=>{ load_track(l[i]); };
}

g.clear();
E.showMenu(menu);