const fs  = require("fs");
const path = require("path");
const os = require("os");
const v8 = require("v8");
const glob = require("glob");
const colorsUtil = require("../cli/util/colors");
const optionsUtil = require("../cli/util/options");
const diff = require("./util/diff");
const asc = require("../cli/asc.js");

const config = {
  "create": {
    "description": [
      "Recreates the fixture for the specified test(s)",
      "or all the fixtures if no specific test is given."
    ],
    "type": "b"
  },
  "createBinary": {
    "description": [
      "Also creates the respective .wasm binaries."
    ],
    "type": "b"
  },
  "noDiff": {
    "description": [
      "Disables output of detailed fixture differences."
    ],
    "type": "b"
  },
  "help": {
    "description": "Prints this message and exits.",
    "type": "b",
    "alias": "h"
  }
};
const opts = optionsUtil.parse(process.argv.slice(2),config);
const args = opts.options;
const argv = opts.arguments;

if (args.help) {
  console.log([
    colorsUtil.white("SYNTAX"),
    "  " + colorsUtil.cyan("npm run test:compiler --") + " [test1, test2 ...] [options]",
    "",
    colorsUtil.white("OPTIONS"),
    optionsUtil.help(config)
  ].join(os.EOL) + os.EOL);
  process.exit(0);
}

const features = process.env.ASC_FEATURES ? process.env.ASC_FEATURES.split(",") : [];
const featuresConfig = require("./features.json");

var failedTests = [];
var failedMessages = new Map();
var skippedTests = [];
var skippedMessages = new Map();

const basedir = path.join(__dirname, "compiler");

// Get a list of all tests
var tests = glob.sync("**/!(_*).ts", { cwd: basedir });

// Run specific tests only if arguments are provided
if (argv.length) {
  tests = tests.filter(filename => argv.indexOf(filename.replace(/\.ts$/, "")) >= 0);
  if (!tests.length) {
    console.error("No matching tests: " + argv.join(" "));
    process.exit(1);
  }
}

const EXPECT_ERROR_PREFIX = '// Expect error:';

// Returns an array of error strings to expect, or null if compilation should succeed.
function getExpectedErrors(filePath) {
  const lines = fs.readFileSync(filePath).toString().split('\n');
  const expectErrorLines = lines.filter(line => line.startsWith(EXPECT_ERROR_PREFIX));
  if (expectErrorLines.length === 0) {
    return null;
  }
  return expectErrorLines.map(line => line.slice(EXPECT_ERROR_PREFIX.length).trim());
}

// TODO: asc's callback is synchronous here. This might change.
tests.forEach(filename => {
  console.log(colorsUtil.white("Testing compiler/" + filename) + "\n");

  const expectedErrors = getExpectedErrors(path.join(basedir, filename));
  const basename = filename.replace(/\.ts$/, "");

  const stdout = asc.createMemoryStream();
  const stderr = asc.createMemoryStream(chunk => process.stderr.write(chunk.toString().replace(/^(?!$)/mg, "  ")));
  stderr.isTTY = true;

  const configPath = path.join(basedir, basename + ".json");
  const config = fs.existsSync(configPath)
    ? require(configPath)
    : {};

  var asc_flags = [];
  var v8_flags = "";
  var v8_no_flags = "";
  var missing_features = [];
  if (config.features) {
    config.features.forEach(feature => {
      if (!features.includes(feature)) missing_features.push(feature);
      var featureConfig = featuresConfig[feature];
      if (featureConfig.asc_flags) {
        featureConfig.asc_flags.forEach(flag => {
          Array.prototype.push.apply(asc_flags, flag.split(" "));
        });
      }
      if (featureConfig.v8_flags) {
        featureConfig.v8_flags.forEach(flag => {
          if (v8_flags) v8_flags += " ";
          v8_flags += flag;
          if (v8_no_flags) v8_no_flags += " ";
          v8_no_flags += "--no-" + flag.substring(2);
        });
        v8.setFlagsFromString(v8_flags);
      }
    });
    if (missing_features.length) {
      console.log("- " + colorsUtil.yellow("feature SKIPPED") + " (" + missing_features.join(", ") + ")\n");
      skippedTests.push(basename);
      skippedMessages.set(basename, "feature not enabled");
      return;
    }
  }
  if (config.asc_flags) {
    config.asc_flags.forEach(flag => {
      Array.prototype.push.apply(asc_flags, flag.split(" "));
    });
  }

  var failed = false;

  // TODO: also save stdout/stderr and diff it (-> expected failures)

  // Build unoptimized
  var cmd = [
    filename,
    "--baseDir", basedir,
    "--validate",
    "--measure",
    "--debug",
    "--textFile" // -> stdout
  ];
  if (asc_flags)
    Array.prototype.push.apply(cmd, asc_flags);
  if (args.createBinary)
    cmd.push("--binaryFile", basename + ".untouched.wasm");
  asc.main(cmd, {
    stdout: stdout,
    stderr: stderr
  }, err => {
    console.log();

    if (expectedErrors) {
      const stderrString = stderr.toString();
      for (const expectedError of expectedErrors) {
        if (!stderrString.includes(expectedError)) {
          console.log(`Expected error "${expectedError}" was not in the error output.`);
          console.log("- " + colorsUtil.red("error check ERROR"));
          failedTests.push(basename);
          console.log();
          return;
        }
      }
      console.log("- " + colorsUtil.green("error check OK"));
      console.log();
      return;
    }

    if (err)
      stderr.write(err + os.EOL);
    var actual = stdout.toString().replace(/\r\n/g, "\n");
    if (args.create) {
      fs.writeFileSync(path.join(basedir, basename + ".untouched.wat"), actual, { encoding: "utf8" });
      console.log("- " + colorsUtil.yellow("Created fixture"));
    } else {
      let expected = fs.readFileSync(path.join(basedir, basename + ".untouched.wat"), { encoding: "utf8" }).replace(/\r\n/g, "\n");
      if (args.noDiff) {
        if (expected != actual) {
          console.log("- " + colorsUtil.red("compare ERROR"));
          failed = true;
        } else {
          console.log("- " + colorsUtil.green("compare OK"));
        }
      } else {
        let diffs = diff(basename + ".untouched.wat", expected, actual);
        if (diffs !== null) {
          console.log(diffs);
          console.log("- " + colorsUtil.red("diff ERROR"));
          failed = true;
        } else {
          console.log("- " + colorsUtil.green("diff OK"));
        }
      }
    }
    console.log();

    stdout.length = 0;
    stderr.length = 0;

    // Build optimized
    var cmd = [
      filename,
      "--baseDir", basedir,
      "--validate",
      "--measure",
      "--binaryFile", // -> stdout
      "-O3"
    ];
    if (asc_flags)
      Array.prototype.push.apply(cmd, asc_flags);
    if (args.create)
      cmd.push("--textFile", basename + ".optimized.wat");
    asc.main(cmd, {
      stdout: stdout,
      stderr: stderr
    }, err => {
      console.log();
      if (err)
        stderr.write(err.stack + os.EOL);

      // Instantiate
      try {
        let memory = new WebAssembly.Memory({ initial: 10 });
        let exports = {};

        function getString(ptr) {
          if (!ptr) return "null";
          var U32 = new Uint32Array(exports.memory ? exports.memory.buffer : memory.buffer);
          var U16 = new Uint16Array(exports.memory ? exports.memory.buffer : memory.buffer);
          var dataLength = U32[ptr >>> 2];
          var dataOffset = (ptr + 4) >>> 1;
          var dataRemain = dataLength;
          var parts = [];
          const chunkSize = 1024;
          while (dataRemain > chunkSize) {
            let last = U16[dataOffset + chunkSize - 1];
            let size = last >= 0xD800 && last < 0xDC00 ? chunkSize - 1 : chunkSize;
            let part = U16.subarray(dataOffset, dataOffset += size);
            parts.push(String.fromCharCode.apply(String, part));
            dataRemain -= size;
          }
          return parts.join("") + String.fromCharCode.apply(String, U16.subarray(dataOffset, dataOffset + dataRemain));
        }

        var binaryBuffer = stdout.toBuffer();
        if (args.createBinary)
          fs.writeFileSync(path.join(basedir, basename + ".optimized.wasm"), binaryBuffer);
        let runTime = asc.measure(() => {
          exports = new WebAssembly.Instance(new WebAssembly.Module(binaryBuffer), {
            env: {
              memory,
              abort: function(msg, file, line, column) {
                console.log(colorsUtil.red("  abort: " + getString(msg) + " at " + getString(file) + ":" + line + ":" + column));
              },
              trace: function(msg, n) {
                console.log("  trace: " + getString(msg) + (n ? " " : "") + Array.prototype.slice.call(arguments, 2, 2 + n).join(", "));
              },
              externalFunction: function() { },
              externalConstant: 1
            },
            math: {
              mod: function(a, b) { return a % b; }
            },
            Math,
            Date,

            // tests/declare
            declare: {
              externalFunction: function() { },
              externalConstant: 1,
              "my.externalFunction": function() { },
              "my.externalConstant": 2
            },

            // tests/external
            external: {
              foo: function() {},
              "foo.bar": function() {},
              bar: function() {}
            },
            foo: {
              baz: function() {},
              "var": 3
            }
          }).exports;
          if (exports.main) {
            console.log(colorsUtil.white("  [main]"));
            var code = exports.main();
            console.log(colorsUtil.white("  [exit " + code + "]\n"));
          }
        });
        console.log("- " + colorsUtil.green("instantiate OK") + " (" + asc.formatTime(runTime) + ")");
        console.log("\n  " + Object.keys(exports).map(key => "[" + (typeof exports[key]).substring(0, 3) + "] " + key).join("\n  "));
      } catch (e) {
        console.log("- " + colorsUtil.red("instantiate ERROR: ") + e.stack);
        failed = true;
        failedMessages.set(basename, e.message);
      }

      if (failed) failedTests.push(basename);
      console.log();
    });
  });
  if (v8_no_flags) v8.setFlagsFromString(v8_no_flags);
});

if (skippedTests.length) {
  console.log(colorsUtil.yellow("WARNING: ") + colorsUtil.white(skippedTests.length + " compiler tests have been skipped:\n"));
  skippedTests.forEach(name => {
    var message = skippedMessages.has(name) ? colorsUtil.gray("[" + skippedMessages.get(name) + "]") : "";
    console.log("  " + name + " " + message);
  });
  console.log();
}
if (failedTests.length) {
  process.exitCode = 1;
  console.log(colorsUtil.red("ERROR: ") + colorsUtil.white(failedTests.length + " compiler tests had failures:\n"));
  failedTests.forEach(name => {
    var message = failedMessages.has(name) ? colorsUtil.gray("[" + failedMessages.get(name) + "]") : "";
    console.log("  " + name + " " + message);
  });
  console.log();
}
if (!process.exitCode) {
  console.log("[ " + colorsUtil.white("OK") + " ]");
}