import { createServerFn } from "@tanstack/react-start";
import { execFileSync } from "node:child_process";

const REPO_PATH = process.env.GITUI_REPO_PATH || process.cwd();

function git(args: string[]): string {
  return execFileSync("git", args, {
    cwd: REPO_PATH,
    encoding: "utf-8",
    maxBuffer: 10 * 1024 * 1024,
  }).trim();
}

export interface CommitInfo {
  hash: string;
  shortHash: string;
  author: string;
  date: string;
  message: string;
}

export interface GitStatus {
  staged: Array<{ status: string; path: string }>;
  unstaged: Array<{ status: string; path: string }>;
  untracked: string[];
}

export const getLog = createServerFn({ method: "POST" })
  .inputValidator((d: { count?: number; skip?: number }) => d)
  .handler(async ({ data }) => {
    const count = data.count ?? 50;
    const skip = data.skip ?? 0;
    const raw = git(["log", "--format=%H%x00%h%x00%an%x00%ai%x00%s", "-n", String(count), `--skip=${skip}`]);
    if (!raw) return [] as CommitInfo[];
    return raw.split("\n").map((line): CommitInfo => {
      const [hash, shortHash, author, date, message] = line.split("\x00");
      return { hash, shortHash, author, date, message };
    });
  });

export const getTree = createServerFn({ method: "POST" })
  .inputValidator((d: { ref?: string }) => d)
  .handler(async ({ data }) => {
    const ref = data.ref || "HEAD";
    const raw = git(["ls-tree", "-r", "--name-only", ref]);
    return raw.split("\n").filter(Boolean);
  });

export const getFileContent = createServerFn({ method: "POST" })
  .inputValidator((d: { ref: string; path: string }) => d)
  .handler(async ({ data }) => {
    return git(["show", `${data.ref}:${data.path}`]);
  });

export const getDiff = createServerFn({ method: "POST" })
  .inputValidator((d: string) => d)
  .handler(async ({ data: hash }) => {
    return git(["show", "--format=", "--patch", hash]);
  });

export const getWorkingDiff = createServerFn().handler(async () => {
  return git(["diff"]);
});

export const getStagedDiff = createServerFn().handler(async () => {
  return git(["diff", "--cached"]);
});

export const getStatus = createServerFn().handler(async (): Promise<GitStatus> => {
  const raw = git(["status", "--porcelain"]);
  const staged: GitStatus["staged"] = [];
  const unstaged: GitStatus["unstaged"] = [];
  const untracked: string[] = [];

  for (const line of raw.split("\n").filter(Boolean)) {
    const x = line[0];
    const y = line[1];
    const path = line.slice(3);

    if (x === "?") {
      untracked.push(path);
    } else {
      if (x !== " " && x !== "?") {
        staged.push({ status: x, path });
      }
      if (y !== " " && y !== "?") {
        unstaged.push({ status: y, path });
      }
    }
  }
  return { staged, unstaged, untracked };
});

export const getBranches = createServerFn().handler(async () => {
  const current = git(["branch", "--show-current"]);
  const all = git(["branch", "--format=%(refname:short)"]).split("\n").filter(Boolean);
  return { current, all };
});

export const getCommitDetail = createServerFn({ method: "POST" })
  .inputValidator((d: string) => d)
  .handler(async ({ data: hash }) => {
    const info = git(["show", "--format=%H%x00%h%x00%an%x00%ae%x00%ai%x00%B", "--stat", hash]);
    const [header, ...rest] = info.split("\n\n");
    const [h, shortHash, author, email, date, ...msgParts] = header.split("\x00");
    const message = msgParts.join("\x00");
    const stats = rest.join("\n\n");
    return { hash: h, shortHash, author, email, date, message, stats };
  });