//-*- coding: utf-8 -*-
//Copyright 2018 Therp BV <https://therp.nl>
//License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl.html).
/*global Uint8Array base64js*/

odoo.define('web_drop_target', function(require) {
    var Model = require('web.Model'),
        FormView = require('web.FormView');

    // this is the main contribution of this addon: A mixin you can use
    // to make some widget a drop target. Read on how to use this yourself
    var DropTargetMixin = {
        // add the mime types you want to support here, leave empty for
        // all types. For more control, override _get_drop_item in your class
        _drop_allowed_types: [],

        // a class being applied when the user drags something we can handle
        _drag_over_class: 'o_drag_over',

        start: function() {
            var result = this._super.apply(this, arguments);
            this.$el.on('drop.widget_events', this.proxy('_on_drop'));
            this.$el.on('dragenter.widget_events', this.proxy('_on_dragenter'));
            this.$el.on('dragover.widget_events', this.proxy('_on_dragenter'));
            this.$el.on('dragleave.widget_events', this.proxy('_on_dragleave'));
            return result;
        },

        _on_drop: function(e) {
            var drop_item = this._get_drop_item(e);
            if(!drop_item) {
                return;
            }
            jQuery(e.delegateTarget).removeClass(this._drag_over_class);
            var reader = new FileReader();
            reader.onloadend = this.proxy(
                _.partial(this._handle_file_drop, drop_item.getAsFile())
            );
            reader.readAsArrayBuffer(drop_item.getAsFile());
            e.preventDefault();
        },

        _on_dragenter: function(e) {
            if(this._get_drop_item(e)) {
                e.preventDefault();
                jQuery(e.delegateTarget).addClass(this._drag_over_class);
                return false;
            }
        },

        _on_dragleave: function(e) {
            jQuery(e.delegateTarget).removeClass(this._drag_over_class);
        },

        _get_drop_item: function(e) {
            var self = this,
                dataTransfer = e.originalEvent.dataTransfer,
                drop_item = null;
            _.each(dataTransfer.items, function(item) {
                if(
                    _.contains(self._drop_allowed_types, item.type) ||
                    _.isEmpty(self._drop_allowed_types)
                ) {
                    drop_item = item;
                }
            });
            return drop_item;
        },

        // eslint-disable-next-line no-unused-vars
        _handle_file_drop: function(drop_file, e) {
            // do something here, for example call the helper function below
            // e is the on_load_end handler for the FileReader above,
            // so e.target.result contains an ArrayBuffer of the data
        },

        _handle_file_drop_attach: function(
                drop_file, e, res_model, res_id, extra_data
        ) {
            // helper to upload an attachment and update the sidebar
            var self = this;
            return new Model('ir.attachment').call(
                'create',
                [
                    _.extend({
                        name: drop_file.name,
                        datas: base64js.fromByteArray(
                            new Uint8Array(e.target.result)
                        ),
                        datas_fname: drop_file.name,
                        res_model: res_model,
                        res_id: res_id,
                    }, extra_data || {})
                ]
            )
            .then(function() {
                // try to find a sidebar and update it if we found one
                var p = self;
                while(p && !p.sidebar) {
                    p = p.getParent ? p.getParent() : null;
                }
                if(p) {
                    var sidebar = p.sidebar;
                    sidebar.do_attachement_update(
                        sidebar.dataset, sidebar.model_id
                    );
                }
            });
        }
    };

    // and here we apply the mixin to form views, allowing any files and
    // adding them as attachment
    FormView.include(_.extend(DropTargetMixin, {
        _get_drop_file: function() {
            // disable drag&drop when we're on an unsaved record
            if(!this.datarecord.id) {
                return null;
            }
            return this._super.apply(this, arguments);
        },
        _handle_file_drop: function(drop_file, e) {
            return this._handle_file_drop_attach(
                drop_file, e, this.dataset.model, this.datarecord.id
            );
        }
    }));

    return {
        'DropTargetMixin': DropTargetMixin,
    };
});