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

import { loadCommitConfig } from "../config/load-config.ts";
import { collectGitChanges, resolveGitRepositoryRoot } from "../git/collect-changes.ts";
import { collectRecentCommitSubjects } from "../git/commit-history.ts";
import { createGitCommit } from "../git/commit.ts";
import { GitClient } from "../git/git-client.ts";
import { GenerationCancelledError } from "../llm/generate-message.ts";
import { buildCommitPrompt } from "../prompt/build-prompt.ts";
import { assertTemplateWithinBudget, loadTemplate } from "../templates/load-template.ts";
import { generateWithWorkingState } from "../ui/generation-loader.ts";
import { showCommitReviewDialog } from "../ui/review-dialog.ts";

const STATUS_KEY = "pi-ai-git-commit";
const CANCELLED_MESSAGE =
  "Cancelled. The Git staging area was not modified and no commit was created.";

/** 设置扩展状态栏文本。 */
function setStatus(ctx: ExtensionCommandContext, message: string | undefined): void {
  ctx.ui.setStatus(STATUS_KEY, message);
}

/** 执行生成、审阅、重新生成和最终提交的完整工作流。 */
export async function runCommitFlow(
  pi: ExtensionAPI,
  ctx: ExtensionCommandContext,
  instruction: string,
): Promise<void> {
  const git = new GitClient(pi);
  const repositoryRoot = await resolveGitRepositoryRoot(git, ctx.cwd);
  const config = await loadCommitConfig(repositoryRoot);
  // 模板内容整个工作流只解析一次，重复生成复用同一系统提示词。
  const template = await loadTemplate(config.template);
  if (template.fallbackReason !== undefined) {
    ctx.ui.notify(
      `Template "${template.requestedName}" could not be loaded. Using built-in "${template.resolvedName}" instead.\n${template.fallbackReason}`,
      "warning",
    );
  }
  assertTemplateWithinBudget(template, config.maxDiffChars);
  const systemPrompt = template.content;
  let previousMessage: string | undefined;

  for (;;) {
    setStatus(ctx, previousMessage ? "Regenerating commit…" : "Generating commit…");
    let context;
    let generated;
    try {
      context = await collectGitChanges(
        git,
        repositoryRoot,
        config.changeSource,
        config.maxDiffChars,
      );
      const recentCommitSubjects = await collectRecentCommitSubjects(
        git,
        context.root,
        config.commitHistoryCount,
      );
      const prompt = buildCommitPrompt(context, {
        language: config.language,
        instructions: config.instructions ?? undefined,
        instruction,
        previousMessage,
        recentCommitSubjects,
      });
      generated = await generateWithWorkingState(
        config,
        systemPrompt,
        prompt,
        ctx,
        previousMessage !== undefined,
      );
    } catch (error) {
      // 用户主动取消生成不是失败，降级为与审阅取消一致的普通提示。
      if (error instanceof GenerationCancelledError) {
        ctx.ui.notify(CANCELLED_MESSAGE, "info");
        return;
      }
      throw error;
    } finally {
      setStatus(ctx, undefined);
    }

    const review = await showCommitReviewDialog(generated, context, ctx, {
      signoff: config.signoff,
    });
    if (review.action === "cancel") {
      ctx.ui.notify(CANCELLED_MESSAGE, "info");
      return;
    }
    if (review.action === "regenerate") {
      // 使用审阅后的消息（可能已被手动编辑），让重新生成能感知用户的修改意图。
      previousMessage = review.message;
      continue;
    }

    setStatus(ctx, "Creating Git commit…");
    try {
      const result = await createGitCommit(git, context, review.message, {
        signoff: config.signoff,
      });
      ctx.ui.notify(`Commit created ${result.hash}\n${review.message}`, "info");
      return;
    } finally {
      setStatus(ctx, undefined);
    }
  }
}