#!/usr/bin/env npx tsx

import * as fs from "fs";
import * as path from "path";

import * as yaml from "yaml";

/** Known workflow input names. */
enum KnownInputName {
  GoVersion = "go-version",
  JavaVersion = "java-version",
  PythonVersion = "python-version",
  DotnetVersion = "dotnet-version",
}

/**
 * Represents workflow input definitions.
 */
interface WorkflowInput {
  type: string;
  description: string;
  required: boolean;
  default: string;
}

/** A partial mapping from known input names to input definitions. */
type WorkflowInputs = Partial<Record<KnownInputName, WorkflowInput>>;

/**
 * Represents PR check specifications.
 */
interface Specification {
  /** The display name for the check. */
  name: string;
  /** The workflow steps specific to this check. */
  steps: any[];
  /** Workflow-level input definitions forwarded to `workflow_dispatch`/`workflow_call`. */
  inputs?: Record<string, WorkflowInput>;
  /** CodeQL bundle versions to test against. Defaults to `DEFAULT_TEST_VERSIONS`. */
  versions?: string[];
  /** Operating system prefixes used to select runner images (e.g. `["ubuntu", "macos"]`). */
  operatingSystems?: string[];
  /** Whether to use the all-platform CodeQL bundle. */
  useAllPlatformBundle?: string;
  /** Values for the `analysis-kinds` matrix dimension. */
  analysisKinds?: string[];

  installNode?: boolean;
  installGo?: boolean;
  installJava?: boolean;
  installPython?: boolean;
  installDotNet?: boolean;
  installYq?: boolean;

  /** Container image configuration for the job. */
  container?: any;
  /** Service containers for the job. */
  services?: any;

  /** Custom permissions override for the job. */
  permissions?: Record<string, string>;
  /** Extra environment variables for the job. */
  env?: Record<string, any>;

  /** If set, this check is part of a named collection that gets its own caller workflow. */
  collection?: string;
}

// The default set of CodeQL Bundle versions to use for the PR checks.
const defaultTestVersions = [
  // The oldest supported CodeQL version. If bumping, update `CODEQL_MINIMUM_VERSION` in `codeql.ts`
  "stable-v2.17.6",
  // The last CodeQL release in the 2.18 series.
  "stable-v2.18.4",
  // The last CodeQL release in the 2.19 series.
  "stable-v2.19.4",
  // The last CodeQL release in the 2.20 series.
  "stable-v2.20.7",
  // The last CodeQL release in the 2.21 series.
  "stable-v2.21.4",
  // The last CodeQL release in the 2.22 series.
  "stable-v2.22.4",
  // The default version of CodeQL for Dotcom, as determined by feature flags.
  "default",
  // The version of CodeQL shipped with the Action in `defaults.json`. During the release process
  // for a new CodeQL release, there will be a period of time during which this will be newer than
  // the default version on Dotcom.
  "linked",
  // A nightly build directly from the our private repo, built in the last 24 hours.
  "nightly-latest",
];

const THIS_DIR = __dirname;
const CHECKS_DIR = path.join(THIS_DIR, "checks");
const OUTPUT_DIR = path.join(THIS_DIR, "..", ".github", "workflows");

/**
 * Loads and parses a YAML file.
 */
function loadYaml(filePath: string): yaml.Document {
  const content = fs.readFileSync(filePath, "utf8");
  return yaml.parseDocument(content);
}

/**
 * Serialize a value to YAML and write it to a file, prepended with the
 * standard header comment.
 */
function writeYaml(filePath: string, workflow: any): void {
  const header = `# Warning: This file is generated automatically, and should not be modified.
# Instead, please modify the template in the pr-checks directory and run:
#     pr-checks/sync.sh
# to regenerate this file.

`;
  const workflowDoc = new yaml.Document(workflow, {
    aliasDuplicateObjects: false,
  });
  const yamlStr = yaml.stringify(workflowDoc, {
    aliasDuplicateObjects: false,
    singleQuote: true,
    lineWidth: 0,
  });
  fs.writeFileSync(filePath, stripTrailingWhitespace(header + yamlStr), "utf8");
}

/**
 * Strip trailing whitespace from each line.
 */
function stripTrailingWhitespace(content: string): string {
  return content
    .split("\n")
    .map((line) => line.trimEnd())
    .join("\n");
}

/**
 * Main entry point for the sync script.
 */
function main(): void {
  // Ensure the output directory exists.
  fs.mkdirSync(OUTPUT_DIR, { recursive: true });

  // Discover and sort all check specification files.
  const checkFiles = fs
    .readdirSync(CHECKS_DIR)
    .filter((f) => f.endsWith(".yml"))
    .sort()
    .map((f) => path.join(CHECKS_DIR, f));

  console.log(`Found ${checkFiles.length} check specification(s).`);

  const collections: Record<
    string,
    Array<{
      specification: Specification;
      checkName: string;
      inputs: Record<string, WorkflowInput>;
    }>
  > = {};

  for (const file of checkFiles) {
    const checkName = path.basename(file, ".yml");
    const specDocument = loadYaml(file);
    const checkSpecification = specDocument.toJS() as Specification;

    console.log(`Processing: ${checkName} — "${checkSpecification.name}"`);

    const workflowInputs: WorkflowInputs = {};
    let matrix: Array<Record<string, any>> = [];

    for (const version of checkSpecification.versions ?? defaultTestVersions) {
      if (version === "latest") {
        throw new Error(
          'Did not recognise "version: latest". Did you mean "version: linked"?',
        );
      }

      const runnerImages = ["ubuntu-latest", "macos-latest", "windows-latest"];
      const operatingSystems = checkSpecification.operatingSystems ?? [
        "ubuntu",
      ];

      for (const operatingSystem of operatingSystems) {
        const runnerImagesForOs = runnerImages.filter((image) =>
          image.startsWith(operatingSystem),
        );

        for (const runnerImage of runnerImagesForOs) {
          matrix.push({
            os: runnerImage,
            version,
          });
        }
      }
    }

    const useAllPlatformBundle = checkSpecification.useAllPlatformBundle
      ? checkSpecification.useAllPlatformBundle
      : "false";

    if (checkSpecification.analysisKinds) {
      const newMatrix: Array<Record<string, any>> = [];
      for (const matrixInclude of matrix) {
        for (const analysisKind of checkSpecification.analysisKinds) {
          newMatrix.push({
            ...matrixInclude,
            "analysis-kinds": analysisKind,
          });
        }
      }
      matrix = newMatrix;
    }

    // Construct the workflow steps needed for this check.
    const steps: any[] = [
      {
        name: "Check out repository",
        uses: "actions/checkout@v6",
      },
    ];

    const installNode = checkSpecification.installNode;

    if (installNode) {
      steps.push(
        {
          name: "Install Node.js",
          uses: "actions/setup-node@v6",
          with: {
            "node-version": "20.x",
            cache: "npm",
          },
        },
        {
          name: "Install dependencies",
          run: "npm ci",
        },
      );
    }

    steps.push({
      name: "Prepare test",
      id: "prepare-test",
      uses: "./.github/actions/prepare-test",
      with: {
        version: "${{ matrix.version }}",
        "use-all-platform-bundle": useAllPlatformBundle,
        // If the action is being run from a container, then do not setup kotlin.
        // This is because the kotlin binaries cannot be downloaded from the container.
        "setup-kotlin": "container" in checkSpecification ? "false" : "true",
      },
    });

    const installGo = checkSpecification.installGo;

    if (installGo) {
      const baseGoVersionExpr = ">=1.21.0";
      workflowInputs[KnownInputName.GoVersion] = {
        type: "string",
        description: "The version of Go to install",
        required: false,
        default: baseGoVersionExpr,
      };

      steps.push({
        name: "Install Go",
        uses: "actions/setup-go@v6",
        with: {
          "go-version":
            "${{ inputs.go-version || '" + baseGoVersionExpr + "' }}",
          // to avoid potentially misleading autobuilder results where we expect it to download
          // dependencies successfully, but they actually come from a warm cache
          cache: false,
        },
      });
    }

    const installJava = checkSpecification.installJava;

    if (installJava) {
      const baseJavaVersionExpr = "17";
      workflowInputs[KnownInputName.JavaVersion] = {
        type: "string",
        description: "The version of Java to install",
        required: false,
        default: baseJavaVersionExpr,
      };

      steps.push({
        name: "Install Java",
        uses: "actions/setup-java@v5",
        with: {
          "java-version":
            "${{ inputs.java-version || '" + baseJavaVersionExpr + "' }}",
          distribution: "temurin",
        },
      });
    }

    const installPython = checkSpecification.installPython;

    if (installPython) {
      const basePythonVersionExpr = "3.13";
      workflowInputs[KnownInputName.PythonVersion] = {
        type: "string",
        description: "The version of Python to install",
        required: false,
        default: basePythonVersionExpr,
      };

      steps.push({
        name: "Install Python",
        if: "matrix.version != 'nightly-latest'",
        uses: "actions/setup-python@v6",
        with: {
          "python-version":
            "${{ inputs.python-version || '" + basePythonVersionExpr + "' }}",
        },
      });
    }

    const installDotNet = checkSpecification.installDotNet;

    if (installDotNet) {
      const baseDotNetVersionExpr = "9.x";
      workflowInputs[KnownInputName.DotnetVersion] = {
        type: "string",
        description: "The version of .NET to install",
        required: false,
        default: baseDotNetVersionExpr,
      };

      steps.push({
        name: "Install .NET",
        uses: "actions/setup-dotnet@v5",
        with: {
          "dotnet-version":
            "${{ inputs.dotnet-version || '" + baseDotNetVersionExpr + "' }}",
        },
      });
    }

    const installYq = checkSpecification.installYq;

    if (installYq) {
      steps.push({
        name: "Install yq",
        if: "runner.os == 'Windows'",
        env: {
          YQ_PATH: "${{ runner.temp }}/yq",
          // This is essentially an arbitrary version of `yq`, which happened to be the one that
          // `choco` fetched when we moved away from using that here.
          // See https://github.com/github/codeql-action/pull/3423
          YQ_VERSION: "v4.50.1",
        },
        run:
          'gh release download --repo mikefarah/yq --pattern "yq_windows_amd64.exe" "$YQ_VERSION" -O "$YQ_PATH/yq.exe"\n' +
          'echo "$YQ_PATH" >> "$GITHUB_PATH"',
      });
    }

    // Extract the sequence of steps from the YAML document to persist as much formatting as possible.
    const specSteps = specDocument.get("steps") as yaml.YAMLSeq;

    // A handful of workflow specifications use double quotes for values, while we generally use single quotes.
    // This replaces double quotes with single quotes for consistency.
    yaml.visit(specSteps, {
      Scalar(_key, node) {
        if (node.type === "QUOTE_DOUBLE") {
          node.type = "QUOTE_SINGLE";
        }
      },
    });

    // Add the generated steps in front of the ones from the specification.
    specSteps.items.unshift(...steps);

    const checkJob: Record<string, any> = {
      strategy: {
        "fail-fast": false,
        matrix: {
          include: matrix,
        },
      },
      name: checkSpecification.name,
      if: "github.triggering_actor != 'dependabot[bot]'",
      permissions: {
        contents: "read",
        "security-events": "read",
      },
      "timeout-minutes": 45,
      "runs-on": "${{ matrix.os }}",
      steps: specSteps,
    };

    if (checkSpecification.permissions) {
      checkJob.permissions = checkSpecification.permissions;
    }

    for (const key of ["env", "container", "services"] as const) {
      if (checkSpecification[key] !== undefined) {
        checkJob[key] = checkSpecification[key];
      }
    }

    checkJob.env = checkJob.env ?? {};
    if (!("CODEQL_ACTION_TEST_MODE" in checkJob.env)) {
      checkJob.env.CODEQL_ACTION_TEST_MODE = true;
    }

    // If this check belongs to a named collection, record it.
    if (checkSpecification.collection) {
      const collectionName = checkSpecification.collection;
      if (!collections[collectionName]) {
        collections[collectionName] = [];
      }
      collections[collectionName].push({
        specification: checkSpecification,
        checkName,
        inputs: workflowInputs,
      });
    }

    let extraGroupName = "";
    for (const inputName of Object.keys(workflowInputs)) {
      extraGroupName += "-${{inputs." + inputName + "}}";
    }

    const cron = new yaml.Scalar("0 5 * * *");
    cron.type = yaml.Scalar.QUOTE_SINGLE;

    const workflow = {
      name: `PR Check - ${checkSpecification.name}`,
      env: {
        GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}",
        GO111MODULE: "auto",
      },
      on: {
        push: {
          branches: ["main", "releases/v*"],
        },
        pull_request: {
          types: ["opened", "synchronize", "reopened", "ready_for_review"],
        },
        merge_group: {
          types: ["checks_requested"],
        },
        schedule: [{ cron }],
        workflow_dispatch: {
          inputs: workflowInputs,
        },
        workflow_call: {
          inputs: workflowInputs,
        },
      },
      defaults: {
        run: {
          shell: "bash",
        },
      },
      concurrency: {
        "cancel-in-progress":
          "${{ github.event_name == 'pull_request' || false }}",
        group: checkName + "-${{github.ref}}" + extraGroupName,
      },
      jobs: {
        [checkName]: checkJob,
      },
    };

    const outputPath = path.join(OUTPUT_DIR, `__${checkName}.yml`);
    writeYaml(outputPath, workflow);
  }

  // Write workflow files for collections.
  for (const collectionName of Object.keys(collections)) {
    const jobs: Record<string, any> = {};
    let combinedInputs: Record<string, WorkflowInput> = {};

    for (const check of collections[collectionName]) {
      const { checkName, specification, inputs: checkInputs } = check;
      const checkWith: Record<string, string> = {};

      combinedInputs = { ...combinedInputs, ...checkInputs };

      for (const inputName of Object.keys(checkInputs)) {
        checkWith[inputName] = "${{ inputs." + inputName + " }}";
      }

      jobs[checkName] = {
        name: specification.name,
        permissions: {
          contents: "read",
          "security-events": "read",
        },
        uses: `./.github/workflows/__${checkName}.yml`,
        with: checkWith,
      };
    }

    const collectionWorkflow = {
      name: `Manual Check - ${collectionName}`,
      env: {
        GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}",
        GO111MODULE: "auto",
      },
      on: {
        workflow_dispatch: {
          inputs: combinedInputs,
        },
      },
      jobs,
    };

    const outputPath = path.join(OUTPUT_DIR, `__${collectionName}.yml`);
    writeYaml(outputPath, collectionWorkflow);
  }

  console.log(
    `\nDone. Wrote ${checkFiles.length} workflow file(s) to ${OUTPUT_DIR}`,
  );
}

main();