import type { ExtensionAPI, ExtensionCommandContext } from "@earendil-works/pi-coding-agent";

import { loadCommitConfig } from "../config/load-config.ts";
import { setActiveTemplate } from "../config/update-config.ts";
import { tryResolveGitRepositoryRoot } from "../git/collect-changes.ts";
import { GitClient } from "../git/git-client.ts";
import { listTemplates } from "../templates/list-templates.ts";

const CANCELLED_MESSAGE = "Cancelled. The active template was not changed.";

/** 构建选择器条目文本，模板名后追加来源与激活标记。 */
function buildTemplateLabel(name: string, source: "user" | "builtin", active: boolean): string {
  const markers: string[] = [];
  if (source === "builtin") {
    markers.push("built-in");
  }
  if (active) {
    markers.push("active");
  }
  return markers.length > 0 ? `${name} (${markers.join(", ")})` : name;
}

/**
 * 执行 /git-commit list 的模板切换工作流：
 * 列出全部模板供上下键选择，确认后按项目优先、全局兜底的顺序写入配置。
 */
export async function runListTemplatesFlow(
  pi: ExtensionAPI,
  ctx: ExtensionCommandContext,
): Promise<void> {
  // 模板管理不要求处于 Git 仓库中；不在仓库时仅操作全局配置。
  const projectDir = await tryResolveGitRepositoryRoot(new GitClient(pi), ctx.cwd);

  const config = await loadCommitConfig(projectDir);
  const templates = await listTemplates();
  if (templates.length === 0) {
    ctx.ui.notify("No templates were found. Create one with /git-commit add.", "warning");
    return;
  }

  const labels = templates.map((template) =>
    buildTemplateLabel(template.name, template.source, template.name === config.template),
  );
  const choice = await ctx.ui.select("Select commit message template", labels);
  if (choice === undefined) {
    ctx.ui.notify(CANCELLED_MESSAGE, "info");
    return;
  }

  // 模板名不含空格，标记后缀直接按首个空格截断即可还原。
  const name = choice.split(" ", 1)[0] as string;
  if (name === config.template) {
    ctx.ui.notify(`Template "${name}" is already active.`, "info");
    return;
  }

  const target = await setActiveTemplate(name, projectDir);
  const scopeText = target.scope === "project" ? "project configuration" : "global configuration";
  ctx.ui.notify(`Template "${name}" activated in the ${scopeText}.\n${target.path}`, "info");
}