import { isNode } from '../nodes/identity.js';
import { visit } from '../visit.js';

const escapeChars = {
    '!': '%21',
    ',': '%2C',
    '[': '%5B',
    ']': '%5D',
    '{': '%7B',
    '}': '%7D'
};
const escapeTagName = (tn) => tn.replace(/[!,[\]{}]/g, ch => escapeChars[ch]);
class Directives {
    constructor(yaml, tags) {
        /**
         * The directives-end/doc-start marker `---`. If `null`, a marker may still be
         * included in the document's stringified representation.
         */
        this.docStart = null;
        /** The doc-end marker `...`.  */
        this.docEnd = false;
        this.yaml = Object.assign({}, Directives.defaultYaml, yaml);
        this.tags = Object.assign({}, Directives.defaultTags, tags);
    }
    clone() {
        const copy = new Directives(this.yaml, this.tags);
        copy.docStart = this.docStart;
        return copy;
    }
    /**
     * During parsing, get a Directives instance for the current document and
     * update the stream state according to the current version's spec.
     */
    atDocument() {
        const res = new Directives(this.yaml, this.tags);
        switch (this.yaml.version) {
            case '1.1':
                this.atNextDocument = true;
                break;
            case '1.2':
                this.atNextDocument = false;
                this.yaml = {
                    explicit: Directives.defaultYaml.explicit,
                    version: '1.2'
                };
                this.tags = Object.assign({}, Directives.defaultTags);
                break;
        }
        return res;
    }
    /**
     * @param onError - May be called even if the action was successful
     * @returns `true` on success
     */
    add(line, onError) {
        if (this.atNextDocument) {
            this.yaml = { explicit: Directives.defaultYaml.explicit, version: '1.1' };
            this.tags = Object.assign({}, Directives.defaultTags);
            this.atNextDocument = false;
        }
        const parts = line.trim().split(/[ \t]+/);
        const name = parts.shift();
        switch (name) {
            case '%TAG': {
                if (parts.length !== 2) {
                    onError(0, '%TAG directive should contain exactly two parts');
                    if (parts.length < 2)
                        return false;
                }
                const [handle, prefix] = parts;
                this.tags[handle] = prefix;
                return true;
            }
            case '%YAML': {
                this.yaml.explicit = true;
                if (parts.length !== 1) {
                    onError(0, '%YAML directive should contain exactly one part');
                    return false;
                }
                const [version] = parts;
                if (version === '1.1' || version === '1.2') {
                    this.yaml.version = version;
                    return true;
                }
                else {
                    const isValid = /^\d+\.\d+$/.test(version);
                    onError(6, `Unsupported YAML version ${version}`, isValid);
                    return false;
                }
            }
            default:
                onError(0, `Unknown directive ${name}`, true);
                return false;
        }
    }
    /**
     * Resolves a tag, matching handles to those defined in %TAG directives.
     *
     * @returns Resolved tag, which may also be the non-specific tag `'!'` or a
     *   `'!local'` tag, or `null` if unresolvable.
     */
    tagName(source, onError) {
        if (source === '!')
            return '!'; // non-specific tag
        if (source[0] !== '!') {
            onError(`Not a valid tag: ${source}`);
            return null;
        }
        if (source[1] === '<') {
            const verbatim = source.slice(2, -1);
            if (verbatim === '!' || verbatim === '!!') {
                onError(`Verbatim tags aren't resolved, so ${source} is invalid.`);
                return null;
            }
            if (source[source.length - 1] !== '>')
                onError('Verbatim tags must end with a >');
            return verbatim;
        }
        const [, handle, suffix] = source.match(/^(.*!)([^!]*)$/);
        if (!suffix)
            onError(`The ${source} tag has no suffix`);
        const prefix = this.tags[handle];
        if (prefix)
            return prefix + decodeURIComponent(suffix);
        if (handle === '!')
            return source; // local tag
        onError(`Could not resolve tag: ${source}`);
        return null;
    }
    /**
     * Given a fully resolved tag, returns its printable string form,
     * taking into account current tag prefixes and defaults.
     */
    tagString(tag) {
        for (const [handle, prefix] of Object.entries(this.tags)) {
            if (tag.startsWith(prefix))
                return handle + escapeTagName(tag.substring(prefix.length));
        }
        return tag[0] === '!' ? tag : `!<${tag}>`;
    }
    toString(doc) {
        const lines = this.yaml.explicit
            ? [`%YAML ${this.yaml.version || '1.2'}`]
            : [];
        const tagEntries = Object.entries(this.tags);
        let tagNames;
        if (doc && tagEntries.length > 0 && isNode(doc.contents)) {
            const tags = {};
            visit(doc.contents, (_key, node) => {
                if (isNode(node) && node.tag)
                    tags[node.tag] = true;
            });
            tagNames = Object.keys(tags);
        }
        else
            tagNames = [];
        for (const [handle, prefix] of tagEntries) {
            if (handle === '!!' && prefix === 'tag:yaml.org,2002:')
                continue;
            if (!doc || tagNames.some(tn => tn.startsWith(prefix)))
                lines.push(`%TAG ${handle} ${prefix}`);
        }
        return lines.join('\n');
    }
}
Directives.defaultYaml = { explicit: false, version: '1.2' };
Directives.defaultTags = { '!!': 'tag:yaml.org,2002:' };

export { Directives };
