import { FieldContext } from '@vinejs/vine/types';
import vine from '@vinejs/vine';
import { VineString } from '@vinejs/vine';
import axios from 'axios';
import { ReferenceIdentifierTypes } from '#contracts/enums';

type Options = {
    typeField: string;
};

// Function to check if DOI exists using the DOI API
async function checkDoiExists(doi: string): Promise<boolean> {
    try {
        const response = await axios.default.get(`${doi}`);
        return response.status === 200; // If status is 200, DOI is valid
    } catch (error) {
        return false; // If request fails, DOI does not exist
    }
}

// Function to check if ISBN exists using the Open Library API
async function checkIsbnExists(isbn: string): Promise<boolean> {
    try {
        const response = await axios.default.get(`https://isbnsearch.org/isbn/${isbn}`);
        return response.data && response.status == 200; // If title is returned, ISBN is valid
    } catch (error) {
        return false; // If request fails, ISBN does not exist
    }
}

async function validateReference(value: unknown, options: Options, field: FieldContext) {
    if (typeof value !== 'string') {
        return;
    }

    const type = field.parent[options.typeField];

    if (type === ReferenceIdentifierTypes.URL) {
        if (!/^https?:\/\/[^\s$.?#].[^\s]*$/.test(value)) {
            field.report('The {{ field }} must be a valid URL', 'validateReference', field);
        } else {
            try {
                const exists = await checkDoiExists(value);
                if (!exists) {
                    field.report('The {{ field }} must be an existing DOI', 'validateReference', field);
                }
            } catch (error) {
                field.report('Error checking DOI existence: ' + error.message, 'validateReference', field);
            }
        }
    }
    // Check if the value does not match the DOI pattern
    // The regex pattern ^10.\d{4,9}\/[-._;()/:a-zA-Z0-9]+$ is designed to match valid DOI formats.
    // - ^10. ensures that the string starts with "10."
    // - \d{4,9} matches a sequence of 4 to 9 digits.
    // - \/ matches the literal forward slash character.
    // - [-._;()/:a-zA-Z0-9]+ matches one or more characters that can include uppercase and lowercase letters, digits, and a set of special characters.
    // The i flag at the end of the regex makes the matching case-insensitive, meaning it will match both uppercase and lowercase letters.
    // If the value does not match this pattern, the code inside the if block will execute.
    else if (type === ReferenceIdentifierTypes.DOI) {
        // Extract the DOI from the URL if it starts with 'https://doi.org/'
        const doiPattern = /^https:\/\/doi\.org\/(10.\d{4,9}\/[-._;()/:a-zA-Z0-9]+)$/i;
        const match = value.match(doiPattern);
        const doi = match ? match[1] : value;
        // Check if the extracted DOI or the value itself matches the DOI patter
        if (!/^10.\d{4,9}\/[-._;()/:a-zA-Z0-9]+$/i.test(doi)) {
            field.report('The {{ field }} must be a valid DOI', 'validateReference', field);
        } else {
            try {
                const exists = await checkDoiExists(value);
                if (!exists) {
                    field.report('The {{ field }} must be an existing DOI', 'validateReference', field);
                }
            } catch (error) {
                field.report('Error checking DOI existence: ' + error.message, 'validateReference', field);
            }
        }
    } else if (type === ReferenceIdentifierTypes.ISBN) {
        if (!/^(?=(?:[^0-9]*[0-9]){10}(?:(?:[^0-9]*[0-9]){3})?$)[\d-]+$/.test(value)) {
            field.report('The {{ field }} must be a valid ISBN', 'validateReference', field);
        } else {
            try {
                const exists = await checkIsbnExists(value);
                if (!exists) {
                    field.report('The {{ field }} must be an existing ISBN', 'validateReference', field);
                }
            } catch (error) {
                field.report('Error checking ISBN existence: ' + error.message, 'validateReference', field);
            }
        }
    } else if (type === ReferenceIdentifierTypes.Handle && !/^\d{2,}.\d{4,9}\/[-._;()/:a-zA-Z0-9]+$/.test(value)) {
        /// Extract the Handle from the URL if it contains '/handle/'
        field.report('The {{ field }} must be a valid Handle', 'validateReference', field);
    } else if (
        type === ReferenceIdentifierTypes.URN &&
        !/^urn:[a-zA-Z0-9][a-zA-Z0-9-]{0,31}:[a-zA-Z0-9()+,\-.:=@;$_!*'%/?#]+$/.test(value)
    ) {
        field.report('The {{ field }} must be a valid URN', 'validateReference', field);
    } else if (type === ReferenceIdentifierTypes.ISSN && !/^\d{4}-\d{3}[\dxX]$/.test(value)) {
        field.report('The {{ field }} must be a valid ISSN', 'validateReference', field);
    }
}

export const validateReferenceRule = vine.createRule(validateReference);

declare module '@vinejs/vine' {
    interface VineString {
        validateReference(options: Options): this;
    }
}

VineString.macro('validateReference', function (this: VineString, options: Options) {
    return this.use(validateReferenceRule(options));
});