1 files changed, 327 insertions, 0 deletions
diff --git a/src/data/validators.js b/src/data/validators.js
new file mode 100644
index 0000000..8392222
--- /dev/null
+++ b/src/data/validators.js
@@ -0,0 +1,327 @@
+import { withAggregate } from '../util/sugar.js';
+
+import { color, ENABLE_COLOR } from '../util/cli.js';
+
+import { inspect as nodeInspect } from 'util';
+
+function inspect(value) {
+    return nodeInspect(value, {colors: ENABLE_COLOR});
+}
+
+// Basic types (primitives)
+
+function a(noun) {
+    return (/[aeiou]/.test(noun[0]) ? `an ${noun}` : `a ${noun}`);
+}
+
+function isType(value, type) {
+    if (typeof value !== type)
+        throw new TypeError(`Expected ${a(type)}, got ${typeof value}`);
+
+    return true;
+}
+
+export function isBoolean(value) {
+    return isType(value, 'boolean');
+}
+
+export function isNumber(value) {
+    return isType(value, 'number');
+}
+
+export function isPositive(number) {
+    isNumber(number);
+
+    if (number <= 0)
+        throw new TypeError(`Expected positive number`);
+
+    return true;
+}
+
+export function isNegative(number) {
+    isNumber(number);
+
+    if (number >= 0)
+        throw new TypeError(`Expected negative number`);
+
+    return true;
+}
+
+export function isPositiveOrZero(number) {
+    isNumber(number);
+
+    if (number < 0)
+        throw new TypeError(`Expected positive number or zero`);
+
+    return true;
+}
+
+export function isNegativeOrZero(number) {
+    isNumber(number);
+
+    if (number > 0)
+        throw new TypeError(`Expected negative number or zero`);
+
+    return true;
+}
+
+export function isInteger(number) {
+    isNumber(number);
+
+    if (number % 1 !== 0)
+        throw new TypeError(`Expected integer`);
+
+    return true;
+}
+
+export function isCountingNumber(number) {
+    isInteger(number);
+    isPositive(number);
+
+    return true;
+}
+
+export function isString(value) {
+    return isType(value, 'string');
+}
+
+export function isStringNonEmpty(value) {
+    isString(value);
+
+    if (value.trim().length === 0)
+        throw new TypeError(`Expected non-empty string`);
+
+    return true;
+}
+
+// Complex types (non-primitives)
+
+export function isInstance(value, constructor) {
+    isObject(value);
+
+    if (!(value instanceof constructor))
+        throw new TypeError(`Expected ${constructor.name}, got ${value.constructor.name}`);
+
+    return true;
+}
+
+export function isDate(value) {
+    return isInstance(value, Date);
+}
+
+export function isObject(value) {
+    isType(value, 'object');
+
+    // Note: Please remember that null is always a valid value for properties
+    // held by a CacheableObject. This assertion is exclusively for use in other
+    // contexts.
+    if (value === null)
+        throw new TypeError(`Expected an object, got null`);
+
+    return true;
+}
+
+export function isArray(value) {
+    isObject(value);
+
+    if (!Array.isArray(value))
+        throw new TypeError(`Expected an array, got ${value}`);
+
+    return true;
+}
+
+function validateArrayItemsHelper(itemValidator) {
+    return (item, index) => {
+        try {
+            const value = itemValidator(item);
+
+            if (value !== true) {
+                throw new Error(`Expected validator to return true`);
+            }
+        } catch (error) {
+            error.message = `(index: ${color.green(index)}, item: ${inspect(item)}) ${error.message}`;
+            throw error;
+        }
+    };
+}
+
+export function validateArrayItems(itemValidator) {
+    const fn = validateArrayItemsHelper(itemValidator);
+
+    return array => {
+        isArray(array);
+
+        withAggregate({message: 'Errors validating array items'}, ({ wrap }) => {
+            array.forEach(wrap(fn));
+        });
+
+        return true;
+    };
+}
+
+export function validateInstanceOf(constructor) {
+    return object => isInstance(object, constructor);
+}
+
+// Wiki data (primitives & non-primitives)
+
+export function isColor(color) {
+    isStringNonEmpty(color);
+
+    if (color.startsWith('#')) {
+        if (![1 + 3, 1 + 4, 1 + 6, 1 + 8].includes(color.length))
+            throw new TypeError(`Expected #rgb, #rgba, #rrggbb, or #rrggbbaa, got length ${color.length}`);
+
+        if (/[^0-9a-fA-F]/.test(color.slice(1)))
+            throw new TypeError(`Expected hexadecimal digits`);
+
+        return true;
+    }
+
+    throw new TypeError(`Unknown color format`);
+}
+
+export function isCommentary(commentary) {
+    return isString(commentary);
+}
+
+const isArtistRef = validateReference('artist');
+
+export function isContribution(contrib) {
+    // TODO: Use better object validation for this (supporting aggregates etc)
+
+    isObject(contrib);
+
+    isArtistRef(contrib.who);
+
+    if (contrib.what !== null) {
+        isStringNonEmpty(contrib.what);
+    }
+
+    return true;
+}
+
+export const isContributionList = validateArrayItems(isContribution);
+
+export function isDimensions(dimensions) {
+    isArray(dimensions);
+
+    if (dimensions.length !== 2)
+        throw new TypeError(`Expected 2 item array`);
+
+    isPositive(dimensions[0]);
+    isInteger(dimensions[0]);
+    isPositive(dimensions[1]);
+    isInteger(dimensions[1]);
+
+    return true;
+}
+
+export function isDirectory(directory) {
+    isStringNonEmpty(directory);
+
+    if (directory.match(/[^a-zA-Z0-9_\-]/))
+        throw new TypeError(`Expected only letters, numbers, dash, and underscore, got "${directory}"`);
+
+    return true;
+}
+
+export function isDuration(duration) {
+    isNumber(duration);
+    isPositiveOrZero(duration);
+
+    return true;
+}
+
+export function isFileExtension(string) {
+    isStringNonEmpty(string);
+
+    if (string[0] === '.')
+        throw new TypeError(`Expected no dot (.) at the start of file extension`);
+
+    if (string.match(/[^a-zA-Z0-9_]/))
+        throw new TypeError(`Expected only alphanumeric and underscore`);
+
+    return true;
+}
+
+export function isLanguageCode(string) {
+    // TODO: This is a stub function because really we don't need a detailed
+    // is-language-code parser right now.
+
+    isString(string);
+
+    return true;
+}
+
+export function isName(name) {
+    return isString(name);
+}
+
+export function isURL(string) {
+    isStringNonEmpty(string);
+
+    new URL(string);
+
+    return true;
+}
+
+export function validateReference(type = 'track') {
+    return ref => {
+        isStringNonEmpty(ref);
+
+        const match = ref.trim().match(/^(?:(?<typePart>\S+):(?=\S))?(?<directoryPart>.+)(?<!:)$/);
+
+        if (!match)
+            throw new TypeError(`Malformed reference`);
+
+        const { groups: { typePart, directoryPart } } = match;
+
+        if (typePart && typePart !== type)
+            throw new TypeError(`Expected ref to begin with "${type}:", got "${typePart}:"`);
+
+        if (typePart)
+            isDirectory(directoryPart);
+
+        isName(ref);
+
+        return true;
+    };
+}
+
+export function validateReferenceList(type = '') {
+    return validateArrayItems(validateReference(type));
+}
+
+// Compositional utilities
+
+export function oneOf(...checks) {
+    return value => {
+        const errorMeta = [];
+
+        for (let i = 0, check; check = checks[i]; i++) {
+            try {
+                const result = check(value);
+
+                if (result !== true) {
+                    throw new Error(`Check returned false`);
+                }
+
+                return true;
+            } catch (error) {
+                errorMeta.push([check, i, error]);
+            }
+        }
+
+        // Don't process error messages until every check has failed.
+        const errors = [];
+        for (const [ check, i, error ] of errorMeta) {
+            error.message = (check.name
+                ? `(#${i} "${check.name}") ${error.message}`
+                : `(#${i}) ${error.message}`);
+            error.check = check;
+            errors.push(error);
+        }
+        throw new AggregateError(errors, `Expected one of ${checks.length} possible checks, but none were true`);
+    };
+}