erpnext.utils.BarcodeScanner = class BarcodeScanner {
	constructor(opts) {
		this.frm = opts.frm;

		// field from which to capture input of scanned data
		this.scan_field_name = opts.scan_field_name || "scan_barcode";
		this.scan_barcode_field = this.frm.fields_dict[this.scan_field_name];

		this.barcode_field = opts.barcode_field || "barcode";
		this.serial_no_field = opts.serial_no_field || "serial_no";
		this.batch_no_field = opts.batch_no_field || "batch_no";
		this.qty_field = opts.qty_field || "qty";
		// field name on row which defines max quantity to be scanned e.g. picklist
		this.max_qty_field = opts.max_qty_field;
		// scanner won't add a new row if this flag is set.
		this.dont_allow_new_row = opts.dont_allow_new_row;
		// scanner will ask user to type the quantity instead of incrementing by 1
		this.prompt_qty = opts.prompt_qty;

		this.items_table_name = opts.items_table_name || "items";
		this.items_table = this.frm.doc[this.items_table_name];

		// any API that takes `search_value` as input and returns dictionary as follows
		// {
		//     item_code: "HORSESHOE", // present if any item was found
		//     bar_code: "123456", // present if barcode was scanned
		//     batch_no: "LOT12", // present if batch was scanned
		//     serial_no: "987XYZ", // present if serial no was scanned
		// }
		this.scan_api = opts.scan_api || "erpnext.stock.utils.scan_barcode";
	}

	process_scan() {
		return new Promise((resolve, reject) => {
			let me = this;

			const input = this.scan_barcode_field.value;
			this.scan_barcode_field.set_value("");
			if (!input) {
				return;
			}

			frappe
				.call({
					method: this.scan_api,
					args: {
						search_value: input,
					},
				})
				.then((r) => {
					const data = r && r.message;
					if (!data || Object.keys(data).length === 0) {
						this.show_alert(__("Cannot find Item with this Barcode"), "red");
						this.clean_up();
						reject();
						return;
					}

					me.update_table(data).then(row => {
						row ? resolve(row) : reject();
					});
				});
		});
	}

	update_table(data) {
		return new Promise(resolve => {
			let cur_grid = this.frm.fields_dict[this.items_table_name].grid;

			const {item_code, barcode, batch_no, serial_no} = data;

			let row = this.get_row_to_modify_on_scan(item_code, batch_no);

			if (!row) {
				if (this.dont_allow_new_row) {
					this.show_alert(__("Maximum quantity scanned for item {0}.", [item_code]), "red");
					this.clean_up();
					return;
				}

				// add new row if new item/batch is scanned
				row = frappe.model.add_child(this.frm.doc, cur_grid.doctype, this.items_table_name);
				// trigger any row add triggers defined on child table.
				this.frm.script_manager.trigger(`${this.items_table_name}_add`, row.doctype, row.name);
			}

			if (this.is_duplicate_serial_no(row, serial_no)) {
				this.clean_up();
				return;
			}

			frappe.run_serially([
				() => this.set_selector_trigger_flag(row, data),
				() => this.set_item(row, item_code).then(qty => {
					this.show_scan_message(row.idx, row.item_code, qty);
				}),
				() => this.set_serial_no(row, serial_no),
				() => this.set_batch_no(row, batch_no),
				() => this.set_barcode(row, barcode),
				() => this.clean_up(),
				() => this.revert_selector_flag(),
				() => resolve(row)
			]);
		});
	}

	// batch and serial selector is reduandant when all info can be added by scan
	// this flag on item row is used by transaction.js to avoid triggering selector
	set_selector_trigger_flag(row, data) {
		const {batch_no, serial_no, has_batch_no, has_serial_no} = data;

		const require_selecting_batch = has_batch_no && !batch_no;
		const require_selecting_serial = has_serial_no && !serial_no;

		if (!(require_selecting_batch || require_selecting_serial)) {
			frappe.flags.hide_serial_batch_dialog = true;
		}
	}

	revert_selector_flag() {
		frappe.flags.hide_serial_batch_dialog = false;
	}

	set_item(row, item_code) {
		return new Promise(resolve => {
			const increment = async (value = 1) => {
				const item_data = {item_code: item_code};
				item_data[this.qty_field] = Number((row[this.qty_field] || 0)) + Number(value);
				await frappe.model.set_value(row.doctype, row.name, item_data);
				return value;
			};

			if (this.prompt_qty) {
				frappe.prompt(__("Please enter quantity for item {0}", [item_code]), ({value}) => {
					increment(value).then((value) => resolve(value));
				});
			} else {
				increment().then((value) => resolve(value));
			}
		});
	}

	async set_serial_no(row, serial_no) {
		if (serial_no && frappe.meta.has_field(row.doctype, this.serial_no_field)) {
			const existing_serial_nos = row[this.serial_no_field];
			let new_serial_nos = "";

			if (!!existing_serial_nos) {
				new_serial_nos = existing_serial_nos + "\n" + serial_no;
			} else {
				new_serial_nos = serial_no;
			}
			await frappe.model.set_value(row.doctype, row.name, this.serial_no_field, new_serial_nos);
		}
	}

	async set_batch_no(row, batch_no) {
		if (batch_no && frappe.meta.has_field(row.doctype, this.batch_no_field)) {
			await frappe.model.set_value(row.doctype, row.name, this.batch_no_field, batch_no);
		}
	}

	async set_barcode(row, barcode) {
		if (barcode && frappe.meta.has_field(row.doctype, this.barcode_field)) {
			await frappe.model.set_value(row.doctype, row.name, this.barcode_field, barcode);
		}
	}

	show_scan_message(idx, exist = null, qty = 1) {
		// show new row or qty increase toast
		if (exist) {
			this.show_alert(__("Row #{0}: Qty increased by {1}", [idx, qty]), "green");
		} else {
			this.show_alert(__("Row #{0}: Item added", [idx]), "green")
		}
	}

	is_duplicate_serial_no(row, serial_no) {
		const is_duplicate = row[this.serial_no_field]?.includes(serial_no);

		if (is_duplicate) {
			this.show_alert(__("Serial No {0} is already added", [serial_no]), "orange");
		}
		return is_duplicate;
	}

	get_row_to_modify_on_scan(item_code, batch_no) {
		let cur_grid = this.frm.fields_dict[this.items_table_name].grid;

		// Check if batch is scanned and table has batch no field
		let is_batch_no_scan = batch_no && frappe.meta.has_field(cur_grid.doctype, this.batch_no_field);
		let check_max_qty = this.max_qty_field && frappe.meta.has_field(cur_grid.doctype, this.max_qty_field);

		const matching_row = (row) => {
			const item_match = row.item_code == item_code;
			const batch_match = row.batch_no == batch_no;
			const qty_in_limit = flt(row[this.qty_field]) < flt(row[this.max_qty_field]);

			return item_match
				&& (!is_batch_no_scan || batch_match)
				&& (!check_max_qty || qty_in_limit)
		}

		return this.items_table.find(matching_row) || this.get_existing_blank_row();
	}

	get_existing_blank_row() {
		return this.items_table.find((d) => !d.item_code);
	}

	clean_up() {
		this.scan_barcode_field.set_value("");
		refresh_field(this.items_table_name);
	}
	show_alert(msg, indicator, duration=3) {
		frappe.show_alert({message: msg, indicator: indicator}, duration);
	}
};