import { isObject } from "../../utils/isObject";
import { Keyword, JsonSchemaResolverParams, JsonSchemaValidatorParams, ValidationReturnType } from "../../Keyword";
import { SchemaNode } from "../../types";
import { getValue } from "../../utils/getValue";
import { validateNode } from "../../validateNode";

const KEYWORD = "additionalItems";

export const additionalItemsKeyword: Keyword = {
    id: KEYWORD,
    keyword: KEYWORD,
    order: -10,
    parse: parseAdditionalItems,
    addResolve: (node: SchemaNode) => node.items != null,
    resolve: additionalItemsResolver,
    addValidate: ({ schema }) => schema[KEYWORD] != null && schema[KEYWORD] !== true && Array.isArray(schema.items),
    validate: validateAdditionalItems
};

// must come as last resolver
export function parseAdditionalItems(node: SchemaNode) {
    const { schema, evaluationPath, schemaLocation } = node;
    if (schema.additionalItems == null || schema.additionalItems === false) {
        return;
    }

    const additionalItems = schema[KEYWORD];

    if (!(isObject(additionalItems) || additionalItems === true)) {
        return node.createError("schema-error", {
            pointer: evaluationPath,
            schema,
            value: undefined,
            message: `Keyword '${KEYWORD}' must be an object or a boolean - received '${typeof additionalItems}'`
        });
    }

    if (!Array.isArray(schema.items)) {
        return node.createAnnotation("schema-error", {
            pointer: evaluationPath,
            schema,
            value: undefined,
            message: `Keyword '${KEYWORD}' is only evaluated with a given items-array`
        });
    }

    node.items = node.compileSchema(
        schema.additionalItems,
        `${evaluationPath}/additionalItems`,
        `${schemaLocation}/additionalItems`
    );
}

function additionalItemsResolver({ node, key, data }: JsonSchemaResolverParams) {
    if (Array.isArray(data)) {
        // @attention: items, etc should already have been tried
        const value = getValue(data, key);
        // items is ensures by addResolve
        const { node: childNode, error } = node.items!.reduceNode(value);
        return childNode ?? error;
    }
}

function validateAdditionalItems({ node, data, pointer, path }: JsonSchemaValidatorParams) {
    const { schema } = node;
    if (!Array.isArray(data) || data.length === 0) {
        // - no items to validate
        return;
    }
    if (Array.isArray(schema.items) && schema.items.length >= data.length) {
        // - no additional items
        return;
    }
    const startIndex = Array.isArray(schema.items) ? schema.items.length : 0;
    const errors: ValidationReturnType = [];
    for (let i = startIndex; i < data.length; i += 1) {
        const item = data[i];
        if (node.items) {
            const validationResult = validateNode(node.items, item, `${pointer}/${i}`, path);
            if (validationResult) {
                errors.push(...validationResult);
            }
        } else if (schema.additionalItems === false) {
            errors.push(
                node.createError("additional-items-error", {
                    key: i,
                    pointer: `${pointer}/${i}`,
                    value: data,
                    schema
                })
            );
        }
    }
    return errors;
}