"use strict";

const Promise = require("bluebird");

const execBinary = require("../exec-binary");
const {B} = require("../units/bytes/iec");
const matchOrError = require("../match-or-error");
const errors = require("../errors");
const mapValue = require("../map-value");

/* FIXME: Error handling, eg. device not found errors */

function mapAttributeFlags(flagString) {
	
	let flagBuffer = Buffer.from(flagString.slice(2), "hex");
	let flagByte = flagBuffer.readUInt16BE(0);

	if (flagByte & 128 || flagByte & 64) {
		throw new Error(`Encountered unknown flag byte in flag ${flagString}`);
	} else {
		return {
			autoKeep: Boolean(flagByte & 32),
			eventCount: Boolean(flagByte & 16),
			errorRate: Boolean(flagByte & 8),
			affectsPerformance: Boolean(flagByte & 4),
			updatedOnline: Boolean(flagByte & 2),
			indicatesFailure: Boolean(flagByte & 1),
		};
	}
}

module.exports = {
	attributes: function ({ devicePath }) {
		return Promise.try(() => {
			return execBinary("smartctl", [devicePath])
				.asRoot()
				.withFlags({ attributes: true })
				.singleResult()
				.expectStdout("attributes", /^\s*([0-9]+)\s+([a-zA-Z_-]+)\s+(0x[0-9a-f]{4})\s+([0-9]{3})\s+([0-9]{3})\s+([0-9]{3})\s+(Pre-fail|Old_age)\s+(Always|Offline)\s+(FAILING_NOW|In_the_past|-)\s+(.+)$/gm, {
					required: true,
					matchAll: true,
					result: ([id, attributeName, flags, value, worst, threshold, type, updatedWhen, failedWhen, rawValue]) => {
						return {
							id: parseInt(id),
							name: attributeName,
							flags: mapAttributeFlags(flags),
							value: parseInt(value),
							rawValue: rawValue,
							worstValueSeen: parseInt(worst),
							failureThreshold: parseInt(threshold),
							type: mapValue(type, {
								"Pre-fail": "preFail",
								"Old_age": "oldAge"
							}),
							failingNow: (failedWhen === "FAILING_NOW"),
							failedBefore: (failedWhen === "In_the_past"),
							updatedWhen: mapValue(updatedWhen, {
								"Always": "always",
								"Offline": "offline"
							})
						};
					}
				})
				.execute();
		}).then((output) => {
			return output.result;
		});
	},
	info: function ({ devicePath }) {
		return Promise.try(() => {
			return execBinary("smartctl", [devicePath])
				.asRoot()
				.withFlags({ info: true })
				.expectStdout("smartAvailable", /^SMART support is:\s*(Available|Unavailable|Ambiguous).+$/m, {
					result: ([availability]) => {
						return mapValue(availability, {
							Available: true,
							Unavailable: false,
							Ambiguous: null
						});
					}
				})
				.expectStdout("model", /^Device Model:\s*(.+)$/m, { result: ([value]) => value })
				.expectStdout("modelFamily", /^Model Family:\s*(.+)$/m, { result: ([value]) => value })
				.expectStdout("serialNumber", /^Serial Number:\s*(.+)$/m, { result: ([value]) => value })
				.expectStdout("wwn", /^LU WWN Device Id:\s*(.+)$/m, { result: ([value]) => value })
				.expectStdout("firmwareVersion", /^Firmware Version:\s*(.+)$/m, { result: ([value]) => value })
				.expectStdout("size", /^User Capacity:\s*(.+)$/m, {
					result: ([value]) => {
						try {
							let match = matchOrError(/^([0-9,]+) bytes \[[^\]]+\]$/, value);
							return B(parseInt(match[0].replace(/,/g, "")));
						} catch (error) {
							throw errors.UnexpectedOutput.chain(error, "Could not parse drive capacity", { input: value });
						}
					}
				})
				.expectStdout("rpm", /^Rotation Rate:\s*(.+)$/m, {
					result: ([value]) => {
						try {
							let match = matchOrError(/^([0-9]+) rpm$/, value);
							return parseInt(match[0]);
						} catch (error) {
							throw errors.UnexpectedOutput.chain(error, "Could not parse drive RPM", { input: value });
						}
					}
				})
				.expectStdout("sectorSizes", /^Sector Sizes:\s*(.+)$/m, {
					result: ([value]) => {
						try {
							let match = matchOrError(/^([0-9]+) bytes logical, ([0-9]+) bytes physical$/, value);

							return {
								logical: B(parseInt(match[0])),
								physical: B(parseInt(match[1]))
							};
						} catch (error) {
							throw errors.UnexpectedOutput.chain(error, "Could not parse drive sector sizes", { input: value });
						}
					}
				})
				.expectStdout("formFactor", /^Form Factor:\s*(.+)$/m, { result: ([value]) => value })
				.expectStdout("ataVersion", /^ATA Version is:\s*(.+)$/m, { result: ([value]) => value })
				.expectStdout("sataVersion", /^SATA Version is:\s*(.+)$/m, { result: ([value]) => value })
				.expectStdout("smartEnabled", /^SMART support is:\s*(Enabled|Disabled)$/m, {
					result: ([value]) => {
						return mapValue(value, {
							Enabled: true,
							Disabled: false
						});
					}
				})
				.execute();
		}).then((output) => {
			return output.result;
		});
	},
	scan: function () {
		return Promise.try(() => {
			return execBinary("smartctl")
				.asRoot()
				.withFlags({ scan: true })
				.singleResult()
				.expectStdout("devices", /^([^ ]+) -d ([^ ]+) #.+$/gm, {
					matchAll: true,
					result: ([devicePath, interface_]) => {
						return {
							path: devicePath,
							interface: interface_
						};
					}
				})
				.execute();
		}).then((output) => {
			return output.result;
		});
	}
};