// story: e32s04
import { execFileSync } from "node:child_process";
import fs from "node:fs";
import path from "node:path";
import { GIT_SCOPE_DIRS, SECRET_DENYLIST } from "../config.js";
import { isSecretPath } from "./paths.js";

export interface GitContextResult {
  action: string;
  changed_files: Record<string, string[]>;
  commits?: Array<{ hash: string; subject: string; files: string[] }>;
  diffs?: Record<string, string>;
}

function inScope(filePath: string): boolean {
  const norm = filePath.replace(/\\/g, "/");
  if (isSecretPath(norm)) return false;
  return GIT_SCOPE_DIRS.some((d) => norm === d || norm.startsWith(`${d}/`));
}

function groupByDir(files: string[]): Record<string, string[]> {
  const grouped: Record<string, string[]> = {};
  for (const f of files) {
    const parts = f.split("/");
    const dir = parts.length > 1 ? parts[0] : ".";
    if (!grouped[dir]) grouped[dir] = [];
    grouped[dir].push(f);
  }
  return grouped;
}

function git(repoRoot: string, args: string[]): string {
  return execFileSync("git", args, {
    cwd: repoRoot,
    encoding: "utf8",
    maxBuffer: 10 * 1024 * 1024,
  }).trim();
}

export function getGitContext(repoRoot: string, action: "status" | "log" | "diff"): GitContextResult {
  if (action === "status") {
    const out = git(repoRoot, ["status", "--porcelain"]);
    const files = out
      .split("\n")
      .filter(Boolean)
      .map((line) => line.slice(3).trim())
      .filter(inScope);
    return { action, changed_files: groupByDir(files) };
  }

  if (action === "log") {
    const out = git(repoRoot, [
      "log",
      "-10",
      "--pretty=format:%H|%s",
      "--name-only",
      "--",
      ...GIT_SCOPE_DIRS,
    ]);
    const commits: GitContextResult["commits"] = [];
    let current: { hash: string; subject: string; files: string[] } | null = null;
    for (const line of out.split("\n")) {
      if (line.includes("|")) {
        if (current) commits.push(current);
        const [hash, subject] = line.split("|");
        current = { hash, subject, files: [] };
      } else if (line.trim() && current && inScope(line.trim())) {
        current.files.push(line.trim());
      }
    }
    if (current) commits.push(current);
    return { action, changed_files: {}, commits };
  }

  const diffOut = git(repoRoot, ["diff", "--", ...GIT_SCOPE_DIRS]);
  const diffs: Record<string, string> = {};
  let currentFile = "";
  let buf: string[] = [];
  for (const line of diffOut.split("\n")) {
    if (line.startsWith("diff --git")) {
      if (currentFile && buf.length) diffs[currentFile] = buf.join("\n");
      const match = / b\/(.+)$/.exec(line);
      currentFile = match?.[1] ?? "";
      buf = [line];
    } else {
      buf.push(line);
    }
  }
  if (currentFile && buf.length && inScope(currentFile) && !isSecretPath(currentFile)) {
    diffs[currentFile] = buf.join("\n");
  }

  const changed = Object.keys(diffs);
  return { action, changed_files: groupByDir(changed), diffs };
}

export function isGitRepo(repoRoot: string): boolean {
  return fs.existsSync(path.join(repoRoot, ".git"));
}