import { isNode } from '../nodes/Node.esnext';
import { visit } from '../visit.esnext';

const escapeChars = {
  "!": "%21",
  ",": "%2C",
  "[": "%5B",
  "]": "%5D",
  "{": "%7B",
  "}": "%7D"
};
const escapeTagName = (tn) => tn.replace(/[!,[\]{}]/g, (ch) => escapeChars[ch]);
class Directives {
  constructor(yaml, tags) {
    this.docStart = null;
    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 "!";
    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;
    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 };
