"use strict";

const fs = require("fs");
const path = require("path");
const { spawnSync } = require("child_process");
const { toRoadCompilerInput } = require("./area-config");

function compilerCli() {
  const packageFile = require.resolve("@osm-asset/road-compiler/package.json");
  const packageRoot = path.dirname(packageFile);
  const manifest = require(packageFile);
  return path.join(packageRoot, typeof manifest.bin === "string" ? manifest.bin : manifest.bin["road-compiler"]);
}

function writeInput(area) {
  const input = toRoadCompilerInput(area);
  fs.mkdirSync(area.outputs.pipelineDir, { recursive: true });
  const file = path.join(area.outputs.pipelineDir, "road-compiler.input.json");
  fs.writeFileSync(file, `${JSON.stringify(input, null, 2)}\n`);
  return { file, input };
}

function parseCompletionMarker(stdout, input) {
  const lines = String(stdout).split(/\r?\n/).filter((line) => line.startsWith("NATIVE_ROAD_COMPILE_DONE "));
  if (lines.length !== 1) throw new Error(`Expected exactly one NATIVE_ROAD_COMPILE_DONE marker, found ${lines.length}`);
  let marker;
  try { marker = JSON.parse(lines[0].slice("NATIVE_ROAD_COMPILE_DONE ".length)); }
  catch (error) { throw new Error(`Invalid NATIVE_ROAD_COMPILE_DONE JSON: ${error.message}`); }
  if (!marker || typeof marker !== "object") throw new Error("NATIVE_ROAD_COMPILE_DONE payload must be an object");
  if (marker.areaId !== input.areaId) throw new Error(`NATIVE_ROAD_COMPILE_DONE areaId mismatch: expected ${input.areaId}, got ${marker.areaId}`);
  if (path.resolve(marker.output || "") !== path.resolve(input.outDir)) throw new Error(`NATIVE_ROAD_COMPILE_DONE output mismatch: expected ${input.outDir}, got ${marker.output}`);
  return marker;
}

function compileArea(area) {
  const { file, input } = writeInput(area);
  const result = spawnSync(process.execPath, [compilerCli(), "--input", file], { encoding: "utf8", stdio: ["ignore", "pipe", "inherit"] });
  if (result.stdout) process.stdout.write(result.stdout);
  if (result.error) throw result.error;
  if (result.status !== 0) {
    const signal = result.signal ? ` signal=${result.signal}` : "";
    throw new Error(`Native road compiler failed with status=${result.status}${signal}`);
  }
  return parseCompletionMarker(result.stdout, input);
}

module.exports = { compileArea, compilerCli, parseCompletionMarker, writeInput };