import { execSync } from "node:child_process";
import { existsSync } from "node:fs";
import { type } from "arktype";
import { log } from "../utils/cli.ts";
import type { ToolContext } from "./server.ts";
import { execute, tool } from "./shared.ts";

const EmptyParams = type({});

async function runInstallation(): Promise<unknown[]> {
  if (!existsSync("package.json")) {
    return [];
  }
  try {
    log.info("» installing Node.js dependencies...");
    execSync("npm install --silent", { stdio: "pipe" });
    log.info("» Node.js dependencies installed");
    return [{ language: "node", installed: true }];
  } catch (err) {
    const msg = err instanceof Error ? err.message : String(err);
    log.warning(`» dependency installation failed: ${msg}`);
    return [{ language: "node", installed: false, error: msg }];
  }
}

export function startInstallation(ctx: ToolContext): void {
  if (ctx.toolState.dependencyInstallation) return;

  const promise = runInstallation();
  ctx.toolState.dependencyInstallation = {
    status: "in_progress",
    promise,
    results: undefined,
  };

  promise.then(
    (results) => {
      if (ctx.toolState.dependencyInstallation) {
        ctx.toolState.dependencyInstallation.status = "completed";
        ctx.toolState.dependencyInstallation.results = results;
      }
    },
    () => {
      if (ctx.toolState.dependencyInstallation) {
        ctx.toolState.dependencyInstallation.status = "failed";
      }
    }
  );
}

export function StartDependencyInstallationTool(ctx: ToolContext) {
  return tool({
    name: "start_dependency_installation",
    description:
      "Start installing project dependencies in the background. Non-blocking, returns immediately. Call early after branch checkout.",
    parameters: EmptyParams,
    execute: execute(async () => {
      const state = ctx.toolState.dependencyInstallation;
      if (state?.status === "completed" || state?.status === "failed") {
        return { status: state.status, message: "Dependency installation already completed." };
      }
      if (state?.status === "in_progress") {
        return { status: "in_progress", message: "Dependency installation is already in progress." };
      }
      startInstallation(ctx);
      return { status: "started", message: "Dependency installation started in background." };
    }),
  });
}

export function AwaitDependencyInstallationTool(ctx: ToolContext) {
  return tool({
    name: "await_dependency_installation",
    description:
      "Wait for dependency installation to complete. Auto-starts if not yet started.",
    parameters: EmptyParams,
    execute: execute(async () => {
      if (!ctx.toolState.dependencyInstallation) {
        startInstallation(ctx);
      }
      const state = ctx.toolState.dependencyInstallation;
      if (!state) throw new Error("failed to initialize dependency installation state");
      if (state.status === "completed" || state.status === "failed") {
        return { status: state.status, message: "Dependency installation complete." };
      }
      if (!state.promise) throw new Error("dependency installation state corrupted");
      await state.promise;
      return { status: state.status, message: "Dependency installation complete." };
    }),
  });
}