DaQuirm/nexus

var nx = {
    Cell:    require('../core/cell'),
    Mapping: require('../core/mapping')
};

var renderers = require('./renderers');

var nxt = {
    NodeRenderer: renderers('NodeRenderer')
};

nxt.ContentRegion = function (domContext) {
    this.domContext = domContext;
    this.cells = [];
};

nxt.ContentRegion.prototype.add = function (commandCell) {
    var _this = this;
    var cell = new nx.Cell({
        value: {
            index: this.cells.length,
            // copying domContext, because its `content` and `renderer` fields
            // are different for each cell
            domContext: {
                container:       this.domContext.container,
                insertReference: this.domContext.insertReference
            },
            visible: false
        },
        action: function (state) { _this.update(state); }
    });

    commandCell.bind(cell, '->>', new nx.Mapping({ '_': 'command' }));
    this.cells.push(cell);
};

nxt.ContentRegion.prototype.update = function (state) {
    var hasRenderer = typeof state.renderer !== 'undefined';
    var noCommand = typeof state.command === 'undefined';
    if (hasRenderer) {
        if (noCommand) {
            state.domContext.content = state.renderer.unrender(state.domContext);
            state.visible = false;
            delete state.renderer;
        }
        else if (state.renderer !== renderers(state.command.type + 'Renderer')) {
            state.domContext.content = state.renderer.unrender(state.domContext);
        }
    }
    if (!noCommand) {
        state.domContext.content = state.command.run(state.domContext);
        state.renderer = state.command.renderer;
        if (typeof state.renderer.visible === 'function') {
            state.visible = state.renderer.visible(state.domContext.content);
        } else {
            state.visible = nxt.NodeRenderer.visible(state.domContext.content);
        }
    }
    var insertReference;
    if (state.visible) {
        insertReference = Array.isArray(state.domContext.content)
            ? state.domContext.content[0]
            : state.domContext.content; // cell's content will serve as an insert reference
    } else {
        // item's right visible neighbor will serve as an insert reference
        insertReference = state.domContext.insertReference;
    }
    for (var index = state.index - 1; index >= 0; index--) {
        this.cells[index].value.domContext.insertReference = insertReference;
        if (this.cells[index].value.visible) { break; }
    }
};

module.exports = nxt.ContentRegion;