import type { ExtensionAPI } from "@jaeswift/jae-coding-agent";
import { Type } from "@sinclair/typebox";

export default function (pi: ExtensionAPI) {
  async function reviewDiff(diff: string, ctx: any): Promise<string> {
    if (!diff.trim()) return "No diff content to review.";

    const lines = diff.split("\n");
    const stats = {
      filesChanged: 0,
      additions: 0,
      deletions: 0,
      files: [] as string[],
    };

    for (const line of lines) {
      if (line.startsWith("+++ b/")) {
        stats.filesChanged++;
        stats.files.push(line.replace("+++ b/", ""));
      } else if (line.startsWith("+") && !line.startsWith("+++")) {
        stats.additions++;
      } else if (line.startsWith("-") && !line.startsWith("---")) {
        stats.deletions++;
      }
    }

    return [
      `## PR Review Summary`,
      ``,
      `**Files changed:** ${stats.filesChanged}`,
      `**Additions:** +${stats.additions}`,
      `**Deletions:** -${stats.deletions}`,
      ``,
      `### Files:`,
      ...stats.files.map((f) => `- ${f}`),
      ``,
      `### Diff Preview (first 200 lines):`,
      "```diff",
      lines.slice(0, 200).join("\n"),
      "```",
      ``,
      `> Full review requires LLM analysis. Send this diff as context to JAE for detailed review.`,
    ].join("\n");
  }

  pi.registerTool({
    name: "pr_review",
    label: "PR Review",
    description: "Review a pull request or git diff. Provide a branch name, PR URL, or commit range.",
    parameters: Type.Object({
      target: Type.String({ description: "Branch name, PR URL, or commit range (e.g., 'main..feature', 'origin/main')" }),
    }),
    execute: async (args, ctx) => {
      const { target } = args;
      let diff = "";

      // Try as branch comparison
      const diffResult = await pi.exec(
        "git",
        ["diff", target],
        { cwd: ctx.cwd },
      );

      if (diffResult.code === 0 && diffResult.stdout.trim()) {
        diff = diffResult.stdout;
      } else {
        // Try as range
        const rangeResult = await pi.exec(
          "git",
          ["diff", `${target}`],
          { cwd: ctx.cwd },
        );
        if (rangeResult.code === 0) {
          diff = rangeResult.stdout;
        } else {
          return { error: `Could not get diff for: ${target}. Error: ${diffResult.stderr || rangeResult.stderr}` };
        }
      }

      const review = await reviewDiff(diff, ctx);
      return { output: review };
    },
  });

  pi.registerCommand("pr-review", {
    description: "Review a PR or branch diff: /pr-review <branch|range>",
    handler: async (args, ctx) => {
      const target = args.trim();
      if (!target) {
        ctx.ui.notify("Usage: /pr-review <branch|commit-range>\nExamples:\n  /pr-review main..feature\n  /pr-review origin/main", "info");
        return;
      }

      ctx.ui.notify(`\u{1F50D} Fetching diff for: ${target}...`, "info");

      const diffResult = await pi.exec("git", ["diff", target], { cwd: ctx.cwd });

      if (diffResult.code !== 0) {
        ctx.ui.notify(`Failed to get diff: ${diffResult.stderr}`, "error");
        return;
      }

      if (!diffResult.stdout.trim()) {
        ctx.ui.notify("No differences found.", "info");
        return;
      }

      const review = await reviewDiff(diffResult.stdout, ctx);
      ctx.ui.notify(review, "info");
    },
  });
}