const vscode = require('vscode');
const { relations } = require('./graph.cjs');
const { uri } = require('./inspection.cjs');

function command(name, args) {
  return `command:${name}?${encodeURIComponent(JSON.stringify(args))}`;
}

async function description(inspection, index, symbol, root) {
  const value = index.documentation.find(item => item.symbol === symbol.name);
  if (!value) return undefined;
  const documentIndex = { files: [index.documentation_files[value.file]] };
  await inspection.verify(documentIndex, 0, root);
  return { ...value, uri: uri(documentIndex, 0, root) };
}

function registerHover(context, selector, inspection, lookup) {
  context.subscriptions.push(vscode.languages.registerHoverProvider(selector, {
    async provideHover(document, position) {
      const state = await lookup(document, position);
      if (!state?.symbols.length) return undefined;
      const contents = [];
      for (const symbol of state.symbols) {
        const page = new vscode.MarkdownString();
        page.isTrusted = { enabledCommands: ['dever.showCalls', 'dever.openDomainLinks', 'dever.previewDocumentation'] };
        page.appendMarkdown(`**${symbol.name}**\n\n`);
        if (state.index.documentation_errors.length) {
          page.appendMarkdown('**说明校验未通过。** 失效或重复的标题详见“Dever”输出；签名和调用关系仍来自源码。\n\n');
        }
        for (const signature of symbol.signatures) page.appendCodeblock(signature, 'dever');
        const detail = await description(inspection, state.index, symbol, state.root);
        if (detail) {
          page.baseUri = detail.uri;
          page.appendMarkdown(`${detail.markdown}\n\n`);
        } else {
          page.appendMarkdown('尚未提供领域说明；签名和关系来自已保存源码。\n\n');
        }
        for (const incoming of [true, false]) {
          const related = relations(state.index, symbol.id, incoming);
          const label = incoming ? '调用方' : '调用目标';
          const names = related.slice(0, 4).map(item => `\`${item.symbol.name}\``).join('、');
          page.appendMarkdown(`${label}：${names || '当前静态索引中无记录'}${related.length > 4 ? `，共 ${related.length} 个` : ''}。\n\n`);
        }
        const links = [];
        for (const site of symbol.declarations.slice(0, 1)) {
          const target = uri(state.index, site.file, state.root).with({ fragment: `L${site.start.line + 1},${site.start.character + 1}` });
          links.push(`[源码](${target.toString()})`);
        }
        if (detail) links.push(`[说明](${command('dever.previewDocumentation', [state.root, symbol.name])})`);
        links.push(`[调用详情](${command('dever.showCalls', [state.root, symbol.name])})`);
        links.push(`[领域流程](${command('dever.openDomainLinks', [state.root, symbol.name])})`);
        page.appendMarkdown(links.join(' · '));
        contents.push(page);
      }
      return new vscode.Hover(contents);
    }
  }));
}

module.exports = { registerHover, description, command };