import * as fs from "node:fs";
import * as path from "node:path";
import { VerificationLayer, VerificationResult, VerificationCheck } from "./types.js";

const TEST_FRAMEWORK_PATTERNS = [
  { name: "Jest", pattern: /jest\.config\.(js|ts|mjs|cjs)|"jest":\s*\{|describe\s*\(|it\s*\(|test\s*\(/ },
  { name: "Mocha", pattern: /mocha|describe\s*\(|it\s*\(/ },
  { name: "Vitest", pattern: /vitest\.config\.(ts|js)|from\s+['"]vitest['"]/ },
];

const MUST_HAVE_KEYWORDS = [
  "must", "shall", "required", "needs to", "has to", "will",
  "should", "critical", "essential", "mandatory", "necessary",
];

export class BehavioralVerification extends VerificationLayer {
  readonly layer = 2;
  readonly name = "Behavioral";

  async verify(projectPath: string, phase: number): Promise<VerificationResult> {
    const start = Date.now();
    const checks: VerificationCheck[] = [];

    checks.push(this.checkTestFramework(projectPath));
    checks.push(this.checkTestFiles(projectPath));
    checks.push(this.checkSpecificationRequirements(projectPath));
    checks.push(this.checkPlanMustHaves(projectPath, phase));
    checks.push(this.checkCodeHasExports(projectPath));

    const passed = checks.every((c) => c.status !== "fail");
    return {
      layer: this.layer,
      name: this.name,
      passed,
      checks,
      summary: `${checks.filter((c) => c.status === "pass").length}/${checks.length} checks passed`,
      duration_ms: Date.now() - start,
    };
  }

  private checkTestFramework(projectPath: string): VerificationCheck {
    const packageJsonPath = path.join(projectPath, "package.json");
    if (!fs.existsSync(packageJsonPath)) {
      return this.check("Test framework detected", "skipped", "No package.json found");
    }

    const packageJson = JSON.parse(fs.readFileSync(packageJsonPath, "utf-8"));
    const devDeps = Object.keys(packageJson.devDependencies || {});
    const deps = Object.keys(packageJson.dependencies || {});
    const allDeps = [...devDeps, ...deps];

    const testDeps = allDeps.filter((d) =>
      ["jest", "mocha", "vitest", "jasmine", "ava", "tape"].includes(d)
    );

    if (testDeps.length > 0) {
      return this.check(
        "Test framework detected",
        "pass",
        `Found test framework(s): ${testDeps.join(", ")}`
      );
    }

    const configFiles = ["jest.config.js", "jest.config.ts", "vitest.config.ts", "vitest.config.js", ".mocharc.yml", ".mocharc.json"];
    const foundConfig = configFiles.filter((f) => fs.existsSync(path.join(projectPath, f)));

    if (foundConfig.length > 0) {
      return this.check(
        "Test framework detected",
        "pass",
        `Found test config: ${foundConfig.join(", ")}`
      );
    }

    return this.check(
      "Test framework detected",
      "warning",
      "No test framework found in dependencies or config files"
    );
  }

  private checkTestFiles(projectPath: string): VerificationCheck {
    const testDirs = ["src", "test", "tests", "__tests__"];
    const testFiles: string[] = [];

    for (const dir of testDirs) {
      const fullPath = path.join(projectPath, dir);
      if (fs.existsSync(fullPath)) {
        testFiles.push(...this.findTestFiles(fullPath, projectPath));
      }
    }

    if (testFiles.length === 0) {
      return this.check(
        "Test files exist",
        "warning",
        "No test files found. Behavioral verification cannot run without tests."
      );
    }

    return this.check(
      "Test files exist",
      "pass",
      `Found ${testFiles.length} test file(s)`
    );
  }

  private checkSpecificationRequirements(projectPath: string): VerificationCheck {
    const specPath = path.join(projectPath, ".ci", "specification.md");
    if (!fs.existsSync(specPath)) {
      return this.check(
        "Specification requirements traceable",
        "skipped",
        "No specification file found"
      );
    }

    const content = fs.readFileSync(specPath, "utf-8");
    const requirements = content
      .split("\n")
      .filter((line) => line.trim().startsWith("- "))
      .map((line) => line.trim().slice(2));

    const mustHaves = requirements.filter((r) =>
      MUST_HAVE_KEYWORDS.some((kw) => r.toLowerCase().includes(kw))
    );

    if (mustHaves.length === 0 && requirements.length === 0) {
      return this.check(
        "Specification requirements traceable",
        "warning",
        "No requirements found in specification"
      );
    }

    return this.check(
      "Specification requirements traceable",
      "pass",
      `Found ${requirements.length} requirement(s), ${mustHaves.length} must-have(s)`
    );
  }

  private checkPlanMustHaves(projectPath: string, phase: number): VerificationCheck {
    const roadmapPath = path.join(
      projectPath,
      ".ci",
      "ROADMAP.md"
    );

    if (!fs.existsSync(roadmapPath)) {
      return this.check(
        "Plan must-haves covered",
        "skipped",
        "No ROADMAP.md found — run 'ci init' first"
      );
    }

    const content = fs.readFileSync(roadmapPath, "utf-8");
    const hasMustHaves = content.toLowerCase().includes("must");
    const hasPhases = content.includes("Phase") || content.includes("phase");

    if (!hasPhases && !hasMustHaves) {
      return this.check(
        "Plan must-haves covered",
        "warning",
        "ROADMAP.md has no phases or must-have items"
      );
    }

    return this.check(
      "Plan must-haves covered",
      "pass",
      "ROADMAP.md contains phase definitions"
    );
  }

  private checkCodeHasExports(projectPath: string): VerificationCheck {
    const srcDir = path.join(projectPath, "src");
    if (!fs.existsSync(srcDir)) {
      return this.check("Source code has exports", "skipped", "No src/ directory found");
    }

    const tsFiles = this.collectTsFiles(srcDir);
    const filesWithoutExports: string[] = [];

    for (const file of tsFiles) {
      const content = fs.readFileSync(file, "utf-8");
      const hasExport = /\bexport\s+/.test(content);
      if (!hasExport && content.trim().length > 0) {
        filesWithoutExports.push(path.relative(projectPath, file));
      }
    }

    if (filesWithoutExports.length === 0) {
      return this.check(
        "Source code has exports",
        "pass",
        `All ${tsFiles.length} source files have exports`
      );
    }

    if (filesWithoutExports.length > tsFiles.length * 0.5) {
      return this.check(
        "Source code has exports",
        "warning",
        `${filesWithoutExports.length}/${tsFiles.length} files have no exports`
      );
    }

    return this.check(
      "Source code has exports",
      "pass",
      `Most files export symbols (${tsFiles.length - filesWithoutExports.length}/${tsFiles.length})`
    );
  }

  private collectTsFiles(dir: string): string[] {
    const files: string[] = [];
    if (!fs.existsSync(dir)) return files;
    const entries = fs.readdirSync(dir, { withFileTypes: true });
    for (const entry of entries) {
      const fullPath = path.join(dir, entry.name);
      if (entry.isDirectory() && entry.name !== "node_modules") {
        files.push(...this.collectTsFiles(fullPath));
      } else if (entry.name.endsWith(".ts") && !entry.name.endsWith(".d.ts") && !entry.name.endsWith(".test.ts")) {
        files.push(fullPath);
      }
    }
    return files;
  }

  private findTestFiles(dir: string, projectPath: string): string[] {
    const files: string[] = [];
    if (!fs.existsSync(dir)) return files;
    const entries = fs.readdirSync(dir, { withFileTypes: true });
    for (const entry of entries) {
      const fullPath = path.join(dir, entry.name);
      if (entry.isDirectory() && entry.name !== "node_modules") {
        files.push(...this.findTestFiles(fullPath, projectPath));
      } else if (
        entry.name.endsWith(".test.ts") ||
        entry.name.endsWith(".test.js") ||
        entry.name.endsWith(".spec.ts") ||
        entry.name.endsWith(".spec.js")
      ) {
        files.push(path.relative(projectPath, fullPath));
      }
    }
    return files;
  }
}