const vscode = require('vscode');
const path = require('node:path');
const { relations } = require('./graph.cjs');
const { uri, projectRoot } = require('./inspection.cjs');
const { openFlowPreview } = require('./dist/flow-preview.cjs');
const { description, command } = require('./hover.cjs');

function registerReading(context, inspection, lookup) {
  const changed = new vscode.EventEmitter();
  const previews = new Map();
  context.subscriptions.push(changed, inspection.changed.event(() => {
    for (const uri of previews.values()) changed.fire(uri);
  }));
  context.subscriptions.push(vscode.workspace.onDidCloseTextDocument(document => {
    previews.delete(document.uri.toString());
  }));
  const provider = {
    onDidChange: changed.event,
    async provideTextDocumentContent(documentUri) {
      previews.set(documentUri.toString(), documentUri);
      const { root, name } = JSON.parse(documentUri.query);
      const index = await inspection.load(root);
      const symbols = index.symbols.filter(symbol => symbol.name === name);
      if (!symbols.length) throw new Error(`函数已不存在：${name}`);
      const lines = [`# ${name}`, '', '静态源码关系；分支可能只执行一部分，任务派发不表示同步执行。', '', index.coverage, ''];
      if (index.documentation_errors.length) lines.push('**说明校验未通过。** 详见“Dever”输出。', '');
      function link(site) {
        const file = index.files[site.file];
        const target = uri(index, site.file, root).with({ fragment: `L${site.start.line + 1},${site.start.character + 1}` });
        return `[${file.path}:${site.start.line + 1}](${target.toString()})`;
      }
      for (const symbol of symbols) {
        for (const signature of symbol.signatures) lines.push('```dever', signature, '```', '');
        const detail = await description(inspection, index, symbol, root);
        if (detail) lines.push(detail.markdown, '', `[主题说明](${detail.uri.toString()})`, '');
        for (const site of symbol.declarations) {
          await inspection.verify(index, site.file, root);
          lines.push('## 定义', '', link(site), '');
        }
        for (const incoming of [true, false]) {
          lines.push(incoming ? '## 谁调用它' : '## 它调用谁', '');
          const related = relations(index, symbol.id, incoming);
          if (!related.length) lines.push('当前已检查源码中没有此类关系。', '');
          else lines.push('| 函数 | 领域 | 关系 | 调用位置 | 定义 / 上下游 |', '| --- | --- | --- | --- | --- |');
          for (const relation of related) {
            for (const call of relation.calls) {
              await inspection.verify(index, call.site.file, root);
              const definitions = relation.symbol.declarations.map(link).join('、') || '内建操作';
              const chain = command('dever.showCalls', [root, relation.symbol.name]);
              lines.push(`| ${relation.symbol.name} | ${relation.symbol.name.split('.').slice(0, 2).join('.')} | ${call.kind} | ${link(call.site)} | ${definitions} · [上下游](${chain}) |`);
            }
          }
          lines.push('');
        }
      }
      return lines.join('\n');
    }
  };
  context.subscriptions.push(vscode.workspace.registerTextDocumentContentProvider('dever-calls', provider));
  context.subscriptions.push(vscode.commands.registerCommand('dever.showCalls', async (root, name) => {
    try {
      if (!root || !name) {
        const editor = vscode.window.activeTextEditor;
        if (!editor) return;
        const state = await lookup(editor.document, editor.selection.active);
        if (!state) throw new Error('请先保存源码，再查看调用关系。');
        if (!state.symbols.length) throw new Error('请把光标放在函数或调用位置。');
        root = state.root;
        name = state.symbols[0].name;
      }
      const target = vscode.Uri.from({ scheme: 'dever-calls', path: '/calls.md', query: JSON.stringify({ root, name }) });
      await openFlowPreview(context, target, root, {
        name,
        changed: inspection.changed,
        read: name => provider.provideTextDocumentContent(target.with({ query: JSON.stringify({ root, name }) }))
      });
    } catch (error) { vscode.window.showErrorMessage(error.message); }
  }));
  context.subscriptions.push(vscode.commands.registerCommand('dever.previewDocumentation', async (root, name) => {
    try {
      const document = vscode.window.activeTextEditor?.document;
      if (!root || !name) {
        if (!document) return;
        const state = await lookup(document, vscode.window.activeTextEditor.selection.active);
        root = state?.root || await projectRoot(document);
        name = state?.symbols[0]?.name;
      }
      const index = await inspection.load(root);
      const symbol = index.symbols.find(value => value.name === name);
      const detail = symbol && await description(inspection, index, symbol, root);
      if (!detail) throw new Error('该符号尚未提供 doc/ 说明。');
      await vscode.commands.executeCommand('markdown.showPreviewToSide', detail.uri.with({ fragment: `L${detail.line + 1}` }));
    } catch (error) { vscode.window.showErrorMessage(error.message); }
  }));
  context.subscriptions.push(vscode.commands.registerCommand('dever.openDomainLinks', async (root, name) => {
    try {
      const document = vscode.window.activeTextEditor?.document;
      if (!root && !document) return;
      root ||= await projectRoot(document);
      const index = await inspection.load(root);
      const symbol = index.symbols.find(value => value.name === name);
      const source = symbol?.declarations[0];
      const filename = source ? index.files[source.file].path : document.uri.fsPath;
      const relative = path.relative(path.join(root, 'module'), filename).split(path.sep);
      if (relative.length < 3 || relative[0] === '..') {
        throw new Error('请在 module/<组件>/<领域>/ 内的源码中执行此命令。');
      }
      const target = vscode.Uri.file(path.join(root, 'module', ...relative.slice(0, 2), 'link.md'));
      await inspection.checkLinks(root);
      const panel = await openFlowPreview(context, target, root);
      const changed = inspection.changed.event(() => panel.dispose());
      panel.onDidDispose(() => changed.dispose());
    } catch (error) {
      vscode.window.showErrorMessage(`${error.message} 可在项目根运行 dever inspect . --links 生成索引。`);
    }
  }));
}

module.exports = { registerReading };