var workflow = {}

// fetch('./test.json')
//   .then((response) => response.json())
//   .then((data) => {
//     for (var key in data) 
//       workflow[key] = data[key];
//   });

// Counters for placeholder IDs of states/actions added via GUI
var stateIdCounter  = workflow.states ? workflow.states.length  : 0;
var actionIdCounter = workflow.states ? workflow.actions.length : 0;

//Actors of the workflow
var actors = [];
workflow.actions.forEach(act => act.actionData.actors.forEach(a => {
  var includes = false;
  actors.forEach(actor => includes = includes || equalRoles(a, actor));
  (!includes) && actors.push(a);
  (!act.actionData.actorNames) && (act.actionData.actorNames = []);
  act.actionData.actorNames.push(getRoleName(a));
}));
// console.log(actors);
// workflow.actions.forEach(a => console.log(a.actionData.actorNames));

function getRoleName(role) {
  if (typeof role == 'string') {
    return role;
  } else if (role.tag == 'payload-reference') {
    return role['payload-label'];
  } else if (role.authorized) {
    return role.authorized['dnf-terms'][0][0].var + ' (auth)';
  } else {
    return role.user || JSON.stringify(role);
  } 
}

const NO_ACTOR = 'None';

//Prepare actor highlighting
const selectedActor = document.getElementById('actor');
var allActors = document.createElement('option');
allActors.text = NO_ACTOR;
selectedActor.add(allActors);
actors.forEach(actor => {
  var option = document.createElement('option');
  option.text = getRoleName(actor);
  selectedActor.add(option);
});


//Viewers of the workflow
var viewers = [];
//Actions/States with no explicit viewers
var viewableByAll = []
//Possible initiators
var initiators = []
//Implicit state from which initial actions can be selected
var initState = null;
//Identify all viewers of every action
workflow.actions.forEach(act => {
  if (act.actionData.viewers.length === 0) {
    viewableByAll.push(act.actionData);
  } else {
    act.actionData.viewers.forEach(v => {
      var includes = false;
      viewers.forEach(viewer => includes = includes || equalRoles(v, viewer));
      (!includes) && viewers.push(v);
      (!act.actionData.viewerNames) && (act.actionData.viewerNames = []);
      act.actionData.viewerNames.push(getRoleName(v));
    })
  }
  if (act.actionData.mode === 'initial') {
    act.actionData.actorNames.forEach(an => !initiators.includes(an) && initiators.push(an));
  }
});
//Identify all viewers of every state
workflow.states.forEach(st => {
  if (st.name === '@@INIT') {
    initState = st;
  } else if (st.stateData.viewers.length === 0) {
    viewableByAll.push(st.stateData);
  } else {
    st.stateData.viewers.forEach(v => {
      var includes = false;
      viewers.forEach(viewer => includes = includes || equalRoles(v, viewer));
      (!includes) && viewers.push(v);
      (!st.stateData.viewerNames) && (st.stateData.viewerNames = []);
      st.stateData.viewerNames.push(getRoleName(v));
    })
  }
});

initState.stateData.viewerNames = initiators;

const ALL_VIEW = "Not explicitly specified";
if (viewableByAll.length > 0) {
  viewers.push(ALL_VIEW);
  var viewerNames = []
  viewers.forEach(viewer => viewerNames.push(getRoleName(viewer)));
  viewableByAll.forEach(data => {
    data.viewerNames = viewerNames;
  });
}


const NO_VIEWER = NO_ACTOR;

//Prepare viewer highlighting
const selectedViewer = document.getElementById('viewer');
var allViewers = document.createElement('option');
allViewers.text = NO_VIEWER;
selectedViewer.add(allViewers);
viewers.forEach(viewer => {
  var option = document.createElement('option');
  option.text = getRoleName(viewer);
  selectedViewer.add(option);
});


//source & target nodes of all currently highlighted actions
var highlightedSources = [];
var highlightedTargets = [];

function selectActor() {
  // console.log(selectedActor.value);
  highlightedSources = [];
  highlightedTargets = [];
  selectedViewer.value = NO_VIEWER;
  workflow.actions.forEach(act => {
    if (act.actionData.mode != 'automatic' && act.actionData.actorNames.includes(selectedActor.value)) {
      highlightedSources.push(act.source.id);
      highlightedTargets.push(act.target.id);
    }
  });
}

function selectViewer() {
  highlightedSources = [];
  highlightedTargets = [];
  selectedActor.value = NO_ACTOR;
  workflow.states.forEach(st => {
    if (st.stateData.viewerNames.includes(selectedViewer.value)) {
      highlightedSources.push(st.id);
    }
  });
}


var selfLoops         = {};  // All edges whose targets equal their sources.
var overlappingEdges  = {};  // All edges whose target and source are connected by further.
const selfLoopCurvMin = 0.5; // Minimum curvature of a self loop.
const curvatureMinMax = 0.2; // Minimum/maximum curvature (1 +/- x) of overlapping edges.

var selection = null; // The currently selected node/edge.
const sidePanel = document.getElementById('sidepanel');

const edgeColourDefault = '#999999ff';
const edgeColourSelected = '#000000ff';
const edgeColourHighlightDefault = 'magenta';
const edgeColourHighlightSelected = 'red';
const edgeColourSubtleDefault = '#99999955';
const edgeColourSubtleSelected = '#00000055';


/**
 * Checks if two roles are equal.
 * @param {*} role1 
 * @param {*} role2 
 * @returns 
 */
function equalRoles(role1, role2) {
  var equal = role1.tag === role2.tag;
  if (role1.tag == 'payload-reference') {
    equal = equal && (role1['payload-label'] === role2['payload-label']);
  } else if (role1.tag == 'user') {
    equal = equal && (role1.user === role2.user);
  } else if (role1.tag == 'authorized') {
    equal = equal && (role1.authorized['dnf-terms'][0][0].var === role2.authorized['dnf-terms'][0][0].var);
  }
  return equal;
}


/**
 * Identifies and stores self loops as well as overlapping edges (i.e. multiple edges sharing the
 * same source and target).
 */
function identifyOverlappingEdges() {
  selfLoops = {};
  overlappingEdges = {};
  workflow.actions.forEach(edge => {
    var source = typeof(edge.source) === 'string' ? edge.source : edge.source.id;
    var target = typeof(edge.target) === 'string' ? edge.target : edge.target.id;
    var pre  = source <= target ? source : target;
    var post = source <= target ? target : source;
    edge.nodePairId = pre + '_' + post;
    var category = edge.source === edge.target ? selfLoops : overlappingEdges;
    if (!category[edge.nodePairId]) category[edge.nodePairId] = [];
    category[edge.nodePairId].push(edge);
  });
}


/**
 * Computes the curvature of the loops stored in `selfLoops` and overlapping edges
 * stored in `overlappingEdges`.
 */
function computeCurvatures() {
  // Self loops
  Object.keys(selfLoops).forEach(id => {
    var edges = selfLoops[id];
    for (let i = 0; i < edges.length; i++)
      edges[i].curvature = selfLoopCurvMin + i / 10;
  });
  // Overlapping edges
  Object.keys(overlappingEdges)
        .filter(nodePairId => overlappingEdges[nodePairId].length > 1)
        .forEach(nodePairId => {
    var edges     = overlappingEdges[nodePairId];
    var lastIndex = edges.length - 1;
    var lastEdge  = edges[lastIndex];
    lastEdge.curvature = curvatureMinMax;
    let delta = 2 * curvatureMinMax / lastIndex;
    for (let i = 0; i < lastIndex; i++) {
      edges[i].curvature = - curvatureMinMax + i * delta;
      if (lastEdge.source !== edges[i].source) edges[i].curvature *= -1;
    }
  });
}


/**
 * Marks the given item as selected.
 * @param {*} item The node or edge to select.
 */
function select(item) {
  selection = selection === item ? null : item;
  if (selection === item) {
    sidePanel.style.display = 'block'
    document.getElementById('sideheading').innerHTML = item.name;
    var data = document.createElement('div');
    var text = document.createTextNode(JSON.stringify(selection.stateData && selection.stateData || selection.actionData));
    data.appendChild(text);
    sidePanel.appendChild(data);
  } else {
    sidePanel.style.display = 'none'
  }
  console.log(item);
  // TODO
}


/**
 * Updates the nodes and edges of the workflow graph.
 */
function updateGraph() {
  identifyOverlappingEdges()
  computeCurvatures()
  Graph.graphData({nodes: workflow.states, links: workflow.actions});
}


/**
 * Adds a new action between two states.
 * @param {*} source The source state.
 * @param {*} target The target state.
 */
function connect(source, target) {
  let linkId = actionIdCounter ++;
  action = {id: linkId, source: source, target: target, name: 'action_' + linkId};
  workflow.actions.push(action);
  updateGraph();
}


/**
 * Adds a new state to the workflow.
 * @param {*} x The x coordinate on the canvas.
 * @param {*} y The y coordinate on the canvas.
 * @returns The new state.
 */
function addState(x, y) {
  let nodeId = stateIdCounter ++;
  state = {id: nodeId, x: x, y: y, name: 'state_' + nodeId, fx: x, fy: y, val: 5};
  workflow.states.push(state);
  updateGraph();
  return state;
}


/**
 * Removes an edge from the workflow.
 * @param {*} action The action to remove.
 */
function removeAction(action) {
  workflow.actions.splice(workflow.actions.indexOf(action), 1);
}


/**
 * Removes a state from the workflow.
 * @param {*} state The state to remove.
 */
function removeState(state) {
  workflow.actions
          .filter(edge => edge.source === state || edge.target === state)
          .forEach(edge => removeAction(edge));
  workflow.states.splice(workflow.states.indexOf(state), 1);
}


/**
 * 
 * @param {*} node 
 * @returns The colour the given node should have.
 */
function getNodeColour(node) {
  var standard = (selectedActor.value === NO_ACTOR && selectedViewer.value === NO_VIEWER)
                || highlightedSources.includes(node.id) || highlightedTargets.includes(node.id)
  var alpha = standard ? 'ff' : '55';
  if (node.stateData && node.stateData.final !== 'False' && node.stateData.final !== '') {
    if (node.stateData.final === 'True' || node.stateData.final === 'ok') {
      return (selection === node ? '#a4eb34' : '#7fad36') + alpha;
    } else if (node.stateData.final === 'not-ok') {
      return (selection === node ? '#f77474' : '#f25050') + alpha;
    } else {
      //console.log(node.stateData.final);
    }
  } else if (node.name === '@@INIT') {
    return (selection === node ? '#e8cd84' : '#d1ad4b') + alpha;
  } else {
    return (selection === node ? '#5fbad9' : '#4496b3') + alpha;
  }
}

function isHighlightedEdge(edge) {
  var data = edge.actionData
  var isViewer    = data.viewerNames.includes(selectedViewer.value)
  var isActor     = data.mode != 'automatic' && data.actorNames.includes(selectedActor.value)
  var isActorAuto = data.mode == 'automatic' && highlightedTargets.includes(edge.source.id)
  return isViewer || isActor || isActorAuto;
}

function getEdgeColour(edge) {
  if (isHighlightedEdge(edge)) {
    return selection === edge ? edgeColourHighlightSelected : edgeColourHighlightDefault;
  } else if (selectedActor.value !== NO_ACTOR) {
    return selection === edge ? edgeColourSubtleSelected : edgeColourSubtleDefault;
  } else {
    return selection === edge ? edgeColourSelected : edgeColourDefault;
  }
}

//Compute abbreviations of the names of all states
var stateAbbreviations = [];
workflow.states.forEach(state => {
  // var label = node.name.substring(0, 5);
  var label = state.name.split(' '); // [node.name.substring(0, 6), node.name.substring(6, 12), node.name.substring(12, 18)];
  for (var i = 0; i < label.length; i++) {
    if (label[i] === '(') continue; // if the state name contains whitespace after the brace
    var isBrace = label[i][0] === '(';
    label[i] = label[i].substring(isBrace ? 1 : 0, isBrace ? 2 : 1);
  }
  labelString = label.join('').substring(0,6);
  var counter = 1;
  var len = labelString.length;
  while (stateAbbreviations.includes(labelString)) {
    labelString = labelString.substring(0,len) + "'" + counter++;
  }
  stateAbbreviations.push(labelString);
  state.stateData.abbreviation = labelString;
});

const Graph = ForceGraph()
  (document.getElementById('graph'))
    .linkDirectionalArrowLength(6)
    .linkDirectionalArrowRelPos(1)
    .linkColor(getEdgeColour)
    .linkCurvature('curvature')
    .linkCanvasObjectMode(() => 'after')
    .linkCanvasObject((edge, context) => {
      const MAX_FONT_SIZE = 4;
      const LABEL_NODE_MARGIN = Graph.nodeRelSize() * edge.source.val * 1.5;

      const source = edge.source;
      const target   = edge.target;
      const curvature = edge.curvature || 0;

      var textPos = (source === target) ? {x: source.x, y: source.y} : Object.assign(...['x', 'y'].map(c => ({
        [c]: source[c] + (target[c] - source[c]) / 2
      })));

      const edgeVector = {x: target.x - source.x, y: target.y - source.y};
      if (source !== target) {
        var evLength = Math.sqrt(Math.pow(edgeVector.x, 2) + Math.pow(edgeVector.y, 2));
        var perpendicular = {x: edgeVector.x, y: (-Math.pow(edgeVector.x, 2) / edgeVector.y)};
        var pLength = Math.sqrt(Math.pow(perpendicular.x, 2) + Math.pow(perpendicular.y, 2));
        perpendicular.x = perpendicular.x / pLength;
        perpendicular.y = perpendicular.y / pLength;
        var fromSource = {x: source.x + perpendicular.x, y: source.y + perpendicular.y};
        // If source would cycle around target in clockwise direction, would fromSource point into this direction?
        // If not, the perpendicular vector must be flipped in order to ensure that the label is displayed on the
        // intended curved edge.
        var isClockwise = (source.x < target.x && fromSource.y > source.y) ||
                          (source.x > target.x && fromSource.y < source.y) ||
                          (source.x === target.x && ((source.y < target.y && fromSource.x < source.x) ||
                                                      source.y > target.y && fromSource.x > source.x));
        var offset = 0.5 * evLength * (isClockwise ? -curvature : curvature);
        textPos = {x: textPos.x + perpendicular.x * offset, y: textPos.y + perpendicular.y * offset};
      } else if (edge.__controlPoints) { // Position label relative to the Bezier control points of the self loop
        edgeVector.x = edge.__controlPoints[2] - edge.__controlPoints[0];
        edgeVector.y = edge.__controlPoints[3] - edge.__controlPoints[1];
        var ctrlCenter = {x: edge.__controlPoints[0] + (edge.__controlPoints[2] - edge.__controlPoints[0]) / 2,
                          y: edge.__controlPoints[1] + (edge.__controlPoints[3] - edge.__controlPoints[1]) / 2};
        var fromSource = {x: ctrlCenter.x - source.x, y: ctrlCenter.y - source.y};
        var fromSrcLen = Math.sqrt(Math.pow(fromSource.x, 2) + Math.pow(fromSource.y, 2));
        fromSource.x /= fromSrcLen;
        fromSource.y /= fromSrcLen;
        // The distance of the control point is 70 * curvature. Slightly more than half of it is appropriate here:
        textPos = {x: source.x + fromSource.x * 37 * curvature, y: source.y + fromSource.y * 37 * curvature};
      }

      const maxTextLength = (source !== target) ? Math.sqrt(Math.pow(edgeVector.x, 2) + Math.pow(edgeVector.y, 2)) - LABEL_NODE_MARGIN
                                                : 1.5 * Math.sqrt(4 * source.val + 100 * curvature);

      var textAngle = Math.atan2(edgeVector.y, edgeVector.x);
      // maintain label vertical orientation for legibility
      if (textAngle > Math.PI / 2) textAngle = -(Math.PI - textAngle);
      if (textAngle < -Math.PI / 2) textAngle = -(-Math.PI - textAngle);

      var label = edge.name;

      // estimate fontSize to fit in link length
      //context.font = '1px Sans-Serif';
      const fontSize = MAX_FONT_SIZE;// Math.min(MAX_FONT_SIZE, maxTextLength / context.measureText(label).width);
      context.font = `${fontSize}px Sans-Serif`;

      var textLen = context.measureText(label).width;
      if (textLen > maxTextLength) {
        var allowedLen = maxTextLength * (label.length / textLen);
        label = label.substring(0, allowedLen);
        if (label !== edge.name) label += '...';
        textLen = context.measureText(label).width;
      }

      const bckgDimensions = [textLen, fontSize];

      // draw text label (with background rect)
      context.save();
      context.translate(textPos.x, textPos.y);
      context.rotate(textAngle);

      context.fillStyle = 'rgba(255, 255, 255, 0.8)';
      context.fillRect(- bckgDimensions[0] / 2, - bckgDimensions[1] / 2, ...bckgDimensions);

      context.textAlign = 'center';
      context.textBaseline = 'middle';
      context.fillStyle = getEdgeColour(edge);
      context.fillText(label, 0, 0);
      context.restore();
    })
    .linkLineDash(edge => edge.actionData.mode == 'automatic' && [2, 3]) //[dash, gap]
    .linkWidth(edge => (isHighlightedEdge(edge)) ? 3 : 1)
    .linkDirectionalParticles(2)
    .linkDirectionalParticleColor(() => '#00000055')
    .linkDirectionalParticleWidth(edge => (isHighlightedEdge(edge)) ? 3 : 0)
    .nodeCanvasObject((node, ctx) => {
      ctx.fillStyle = getNodeColour(node);
      ctx.beginPath();
      ctx.arc(node.x, node.y, 2*node.val, 0, 2 * Math.PI, false);
      ctx.fill();

      if (! (node.stateData && node.stateData.abbreviation)) return;

      ctx.fillStyle = 'white';
      ctx.font = '4px Sans-Serif';
      ctx.textAlign = 'center';
      ctx.textBaseline = 'middle';
      ctx.fillText(node.stateData.abbreviation, node.x, node.y);      
    })
    .onNodeDragEnd(node => {
      node.fx = node.x;
      node.fy = node.y;
    })
    .onNodeClick((node, _) => select(node))
    .onNodeRightClick((node, _) => removeState(node))
    .onLinkClick((edge, _) => select(edge))
    .onLinkRightClick((edge, _) => removeAction(edge))
    .onBackgroundClick(event => {
      var coords = Graph.screen2GraphCoords(event.layerX, event.layerY);
      var newState = addState(coords.x, coords.y);
      selection = newState;
    })
    .autoPauseRedraw(false);

updateGraph();