import _ from 'lodash'
import { Graph } from 'graphlibrary'

import acyclic from './acyclic'
import normalize from './normalize'
import rank from './rank'
import util, { normalizeRanks, removeEmptyRanks } from './util'
import parentDummyChains from './parent-dummy-chains'
import nestingGraph from './nesting-graph'
import addBorderSegments from './add-border-segments'
import coordinateSystem from './coordinate-system'
import order from './order'
import position from './position'

function layout (g, opts) {
  const time = opts && opts.debugTiming ? util.time : util.notime
  time('layout', function () {
    const layoutGraph = time('  buildLayoutGraph',
      function () { return buildLayoutGraph(g) })
    time('  runLayout', function () { runLayout(layoutGraph, time) })
    time('  updateInputGraph', function () { updateInputGraph(g, layoutGraph) })
  })
}

function runLayout (g, time) {
  time('    makeSpaceForEdgeLabels', function () { makeSpaceForEdgeLabels(g) })
  time('    removeSelfEdges', function () { removeSelfEdges(g) })
  time('    acyclic', function () { acyclic.run(g) })
  time('    nestingGraph.run', function () { nestingGraph.run(g) })
  time('    rank', function () { rank(util.asNonCompoundGraph(g)) })
  time('    injectEdgeLabelProxies', function () { injectEdgeLabelProxies(g) })
  time('    removeEmptyRanks', function () { removeEmptyRanks(g) })
  time('    nestingGraph.cleanup', function () { nestingGraph.cleanup(g) })
  time('    normalizeRanks', function () { normalizeRanks(g) })
  time('    assignRankMinMax', function () { assignRankMinMax(g) })
  time('    removeEdgeLabelProxies', function () { removeEdgeLabelProxies(g) })
  time('    normalize.run', function () { normalize.run(g) })
  time('    parentDummyChains', function () { parentDummyChains(g) })
  time('    addBorderSegments', function () { addBorderSegments(g) })
  time('    order', function () { order(g) })
  time('    insertSelfEdges', function () { insertSelfEdges(g) })
  time('    adjustCoordinateSystem', function () { coordinateSystem.adjust(g) })
  time('    position', function () { position(g) })
  time('    positionSelfEdges', function () { positionSelfEdges(g) })
  time('    removeBorderNodes', function () { removeBorderNodes(g) })
  time('    normalize.undo', function () { normalize.undo(g) })
  time('    fixupEdgeLabelCoords', function () { fixupEdgeLabelCoords(g) })
  time('    undoCoordinateSystem', function () { coordinateSystem.undo(g) })
  time('    translateGraph', function () { translateGraph(g) })
  time('    assignNodeIntersects', function () { assignNodeIntersects(g) })
  time('    reversePoints', function () { reversePointsForReversedEdges(g) })
  time('    acyclic.undo', function () { acyclic.undo(g) })
}

/*
 * Copies final layout information from the layout graph back to the input
 * graph. This process only copies whitelisted attributes from the layout graph
 * to the input graph, so it serves as a good place to determine what
 * attributes can influence layout.
 */
function updateInputGraph (inputGraph, layoutGraph) {
  _.forEach(inputGraph.nodes(), function (v) {
    const inputLabel = inputGraph.node(v)
    const layoutLabel = layoutGraph.node(v)

    if (inputLabel) {
      inputLabel.x = layoutLabel.x
      inputLabel.y = layoutLabel.y

      if (layoutGraph.children(v).length) {
        inputLabel.width = layoutLabel.width
        inputLabel.height = layoutLabel.height
      }
    }
  })

  _.forEach(inputGraph.edges(), function (e) {
    const inputLabel = inputGraph.edge(e)
    const layoutLabel = layoutGraph.edge(e)

    inputLabel.points = layoutLabel.points
    if (_.has(layoutLabel, 'x')) {
      inputLabel.x = layoutLabel.x
      inputLabel.y = layoutLabel.y
    }
  })

  inputGraph.graph().width = layoutGraph.graph().width
  inputGraph.graph().height = layoutGraph.graph().height
}

const graphNumAttrs = ['nodesep', 'edgesep', 'ranksep', 'marginx', 'marginy']
const graphDefaults = { ranksep: 50, edgesep: 20, nodesep: 50, rankdir: 'tb' }
const graphAttrs = ['acyclicer', 'ranker', 'rankdir', 'align']
const nodeNumAttrs = ['width', 'height']
const nodeDefaults = { width: 0, height: 0 }
const edgeNumAttrs = ['minlen', 'weight', 'width', 'height', 'labeloffset']
const edgeDefaults = {
  minlen: 1,
  weight: 1,
  width: 0,
  height: 0,
  labeloffset: 10,
  labelpos: 'r'
}
const edgeAttrs = ['labelpos']

/*
 * Constructs a new graph from the input graph, which can be used for layout.
 * This process copies only whitelisted attributes from the input graph to the
 * layout graph. Thus this function serves as a good place to determine what
 * attributes can influence layout.
 */
function buildLayoutGraph (inputGraph) {
  const g = new Graph({ multigraph: true, compound: true })
  const graph = canonicalize(inputGraph.graph())

  g.setGraph(_.merge({},
    graphDefaults,
    selectNumberAttrs(graph, graphNumAttrs),
    _.pick(graph, graphAttrs)))

  _.forEach(inputGraph.nodes(), function (v) {
    const node = canonicalize(inputGraph.node(v))
    g.setNode(v, _.defaults(selectNumberAttrs(node, nodeNumAttrs), nodeDefaults))
    g.setParent(v, inputGraph.parent(v))
  })

  _.forEach(inputGraph.edges(), function (e) {
    const edge = canonicalize(inputGraph.edge(e))
    g.setEdge(e, _.merge({},
      edgeDefaults,
      selectNumberAttrs(edge, edgeNumAttrs),
      _.pick(edge, edgeAttrs)))
  })

  return g
}

/*
 * This idea comes from the Gansner paper: to account for edge labels in our
 * layout we split each rank in half by doubling minlen and halving ranksep.
 * Then we can place labels at these mid-points between nodes.
 *
 * We also add some minimal padding to the width to push the label for the edge
 * away from the edge itself a bit.
 */
function makeSpaceForEdgeLabels (g) {
  const graph = g.graph()
  graph.ranksep /= 2
  _.forEach(g.edges(), function (e) {
    const edge = g.edge(e)
    edge.minlen *= 2
    if (edge.labelpos.toLowerCase() !== 'c') {
      if (graph.rankdir === 'TB' || graph.rankdir === 'BT') {
        edge.width += edge.labeloffset
      } else {
        edge.height += edge.labeloffset
      }
    }
  })
}

/*
 * Creates temporary dummy nodes that capture the rank in which each edge's
 * label is going to, if it has one of non-zero width and height. We do this
 * so that we can safely remove empty ranks while preserving balance for the
 * label's position.
 */
function injectEdgeLabelProxies (g) {
  _.forEach(g.edges(), function (e) {
    const edge = g.edge(e)
    if (edge.width && edge.height) {
      const v = g.node(e.v)
      const w = g.node(e.w)
      const label = { rank: (w.rank - v.rank) / 2 + v.rank, e: e }
      util.addDummyNode(g, 'edge-proxy', label, '_ep')
    }
  })
}

function assignRankMinMax (g) {
  let maxRank = 0
  _.forEach(g.nodes(), function (v) {
    const node = g.node(v)
    if (node.borderTop) {
      node.minRank = g.node(node.borderTop).rank
      node.maxRank = g.node(node.borderBottom).rank
      maxRank = Math.max(maxRank, node.maxRank)
    }
  })
  g.graph().maxRank = maxRank
}

function removeEdgeLabelProxies (g) {
  _.forEach(g.nodes(), function (v) {
    const node = g.node(v)
    if (node.dummy === 'edge-proxy') {
      g.edge(node.e).labelRank = node.rank
      g.removeNode(v)
    }
  })
}

function translateGraph (g) {
  let minX = Number.POSITIVE_INFINITY
  let maxX = 0
  let minY = Number.POSITIVE_INFINITY
  let maxY = 0
  const graphLabel = g.graph()
  const marginX = graphLabel.marginx || 0
  const marginY = graphLabel.marginy || 0

  function getExtremes (attrs) {
    const x = attrs.x
    const y = attrs.y
    const w = attrs.width
    const h = attrs.height
    minX = Math.min(minX, x - w / 2)
    maxX = Math.max(maxX, x + w / 2)
    minY = Math.min(minY, y - h / 2)
    maxY = Math.max(maxY, y + h / 2)
  }

  _.forEach(g.nodes(), function (v) { getExtremes(g.node(v)) })
  _.forEach(g.edges(), function (e) {
    const edge = g.edge(e)
    if (_.has(edge, 'x')) {
      getExtremes(edge)
    }
  })

  minX -= marginX
  minY -= marginY

  _.forEach(g.nodes(), function (v) {
    const node = g.node(v)
    node.x -= minX
    node.y -= minY
  })

  _.forEach(g.edges(), function (e) {
    const edge = g.edge(e)
    _.forEach(edge.points, function (p) {
      p.x -= minX
      p.y -= minY
    })
    if (_.has(edge, 'x')) { edge.x -= minX }
    if (_.has(edge, 'y')) { edge.y -= minY }
  })

  graphLabel.width = maxX - minX + marginX
  graphLabel.height = maxY - minY + marginY
}

function assignNodeIntersects (g) {
  _.forEach(g.edges(), function (e) {
    const edge = g.edge(e)
    const nodeV = g.node(e.v)
    const nodeW = g.node(e.w)
    let p1 = null
    let p2 = null
    if (!edge.points) {
      edge.points = []
      p1 = nodeW
      p2 = nodeV
    } else {
      p1 = edge.points[0]
      p2 = edge.points[edge.points.length - 1]
    }
    edge.points.unshift(util.intersectRect(nodeV, p1))
    edge.points.push(util.intersectRect(nodeW, p2))
  })
}

function fixupEdgeLabelCoords (g) {
  _.forEach(g.edges(), function (e) {
    const edge = g.edge(e)
    if (_.has(edge, 'x')) {
      if (edge.labelpos === 'l' || edge.labelpos === 'r') {
        edge.width -= edge.labeloffset
      }
      switch (edge.labelpos) {
        case 'l': edge.x -= edge.width / 2 + edge.labeloffset; break
        case 'r': edge.x += edge.width / 2 + edge.labeloffset; break
      }
    }
  })
}

function reversePointsForReversedEdges (g) {
  _.forEach(g.edges(), function (e) {
    const edge = g.edge(e)
    if (edge.reversed) {
      edge.points.reverse()
    }
  })
}

function removeBorderNodes (g) {
  _.forEach(g.nodes(), function (v) {
    if (g.children(v).length) {
      const node = g.node(v)
      const t = g.node(node.borderTop)
      const b = g.node(node.borderBottom)
      const l = g.node(_.last(node.borderLeft))
      const r = g.node(_.last(node.borderRight))

      node.width = Math.abs(r.x - l.x)
      node.height = Math.abs(b.y - t.y)
      node.x = l.x + node.width / 2
      node.y = t.y + node.height / 2
    }
  })

  _.forEach(g.nodes(), function (v) {
    if (g.node(v).dummy === 'border') {
      g.removeNode(v)
    }
  })
}

function removeSelfEdges (g) {
  _.forEach(g.edges(), function (e) {
    if (e.v === e.w) {
      const node = g.node(e.v)
      if (!node.selfEdges) {
        node.selfEdges = []
      }
      node.selfEdges.push({ e: e, label: g.edge(e) })
      g.removeEdge(e)
    }
  })
}

function insertSelfEdges (g) {
  const layers = util.buildLayerMatrix(g)
  _.forEach(layers, function (layer) {
    let orderShift = 0
    _.forEach(layer, function (v, i) {
      const node = g.node(v)
      node.order = i + orderShift
      _.forEach(node.selfEdges, function (selfEdge) {
        util.addDummyNode(g, 'selfedge', {
          width: selfEdge.label.width,
          height: selfEdge.label.height,
          rank: node.rank,
          order: i + (++orderShift),
          e: selfEdge.e,
          label: selfEdge.label
        }, '_se')
      })
      delete node.selfEdges
    })
  })
}

function positionSelfEdges (g) {
  _.forEach(g.nodes(), function (v) {
    const node = g.node(v)
    if (node.dummy === 'selfedge') {
      const selfNode = g.node(node.e.v)
      const x = selfNode.x + selfNode.width / 2
      const y = selfNode.y
      const dx = node.x - x
      const dy = selfNode.height / 2
      g.setEdge(node.e, node.label)
      g.removeNode(v)
      node.label.points = [
        { x: x + 2 * dx / 3, y: y - dy },
        { x: x + 5 * dx / 6, y: y - dy },
        { x: x + dx, y: y },
        { x: x + 5 * dx / 6, y: y + dy },
        { x: x + 2 * dx / 3, y: y + dy }
      ]
      node.label.x = node.x
      node.label.y = node.y
    }
  })
}

function selectNumberAttrs (obj, attrs) {
  return _.mapValues(_.pick(obj, attrs), Number)
}

function canonicalize (attrs) {
  const newAttrs = {}
  _.forEach(attrs, function (v, k) {
    newAttrs[k.toLowerCase()] = v
  })
  return newAttrs
}

export default layout