/**
 * complexity.test.ts — integration tests for the excessive complexity check.
 *
 * Tests verify:
 * 1. A 55-decision-point function (must-refactor band) is refactored
 * 2. A 40-decision-point function (heavy-skepticism band) is either refactored
 *    or has a documented justification in findings.md
 * 3. Deep nesting and over-abstraction are simplified
 */
import { describe, expect, it, beforeEach, afterEach } from "bun:test";
import { mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
import {
	clearChecks,
	registerCheck,
	type CheckDefinition,
} from "../src/checks/registry.js";
import {
	setAgentRunner,
	resetAgentRunner,
	fakeAgentRunner,
} from "../src/agent-runner.js";
import { handleCheckCommand, type PygieniumCtx } from "../src/commands.js";
import { loadRunState } from "../src/run-state.js";

/**
 * A synthetic check that simulates a complexity scan finding two functions:
 * - one at complexity 55 (must-refactor band)
 * - one at complexity 40 (skepticism band)
 */
function synthComplexityCheck(): CheckDefinition {
	return {
		name: "synth-complexity",
		label: "Synth Complexity",
		description: "Synthetic complexity check for integration tests",
		agentName: "scanner",
		fixAgentName: "fixer",
		phaseId: "scan",
		buildScanTask: (_cwd, scope) => {
			const findings = `# complexity — findings

## Cyclomatic complexity

| File | Function | Score | Band | Action |
|------|----------|-------|------|--------|
| target/index.ts:10 | complexFunction | 55 | 50+ | MUST refactor |
| target/index.ts:100 | moderateFunction | 40 | 35-49 | Skepticism — justify or refactor |
| target/index.ts:200 | simpleFunction | 8 | <35 | OK |

## Structural smells

- [high] target/index.ts:15 — deep nesting — 5 levels of nested if/else
- [med] target/index.ts:80 — unnecessary wrapper — trivial passthrough function
`;
			// fakeAgentRunner parses one directive per line, so flatten the content
			// onto a single escaped line; the on-disk file keeps the real text.
			const oneLine = findings.split("\n").join(" ");
			return `!write pygienium/checks/synth-complexity/findings.md "${oneLine}"\n!echo ${oneLine}`;
		},
		buildFixTask: (_cwd, _scope, findings) => {
			const changes = `# complexity — changes\n\n2 refactoring(s) applied; 0 deferred for human review.\n\n## Applied\n\n- target/index.ts:10 — complexFunction split (was 55, now 22, 28)\n- target/index.ts:15 — nested conditionals flattened\n- target/index.ts:80 — trivial wrapper inlined\n\n## Deferred (needs human review)\n\n## Justified (kept at 35–49)\n\n- target/index.ts:100 — moderateFunction (40) — kept: critical routing function on main path, would require major architectural change to split\n`;
			const oneLine = changes.split("\n").join(" ");
			return `!write pygienium/checks/synth-complexity/changes.md "${oneLine}"\n!echo ${oneLine}`;
		},
		gate: async (cwd) => {
			const { stat } = await import("node:fs/promises");
			const { resolve } = await import("node:path");
			try {
				const s = await stat(resolve(cwd));
				return s.isDirectory() || s.isFile()
					? undefined
					: `target is not a file or directory: ${resolve(cwd)}`;
			} catch {
				return `target path does not exist: ${resolve(cwd)}`;
			}
		},
	};
}

function stubCtx(cwd: string): PygieniumCtx {
	return { cwd, mode: "print", hasUI: false, ui: undefined } as PygieniumCtx;
}

describe("complexity check integration", () => {
	let cwd: string;

	beforeEach(async () => {
		clearChecks();
		setAgentRunner(fakeAgentRunner);
		cwd = await mkdtemp(join(tmpdir(), "pygienium-complexity-"));
	});

	afterEach(async () => {
		resetAgentRunner();
		await rm(cwd, { recursive: true, force: true });
	});

	it("runs a complexity scan and writes findings with cyclomatic scores", async () => {
		registerCheck(synthComplexityCheck());
		const check = synthComplexityCheck();

		await handleCheckCommand(check, "", stubCtx(cwd));

		const state = await loadRunState(cwd);
		expect(state).toBeDefined();
		expect(state?.checks["synth-complexity"].status).toBe("complete");

		// Verify findings contain complexity scores
		const findings = state?.checks["synth-complexity"].findings;
		expect(findings).toContain("55");
		expect(findings).toContain("40");
		expect(findings).toContain("MUST refactor");
	});

	it("--fix refactors the 50+ function and documents changes", async () => {
		const check = synthComplexityCheck();
		await handleCheckCommand(check, "--fix", stubCtx(cwd));

		const state = await loadRunState(cwd);
		expect(state?.checks["synth-complexity"].status).toBe("complete");

		// Verify changes document the refactoring
		const changes = state?.checks["synth-complexity"].changes;
		expect(changes).toContain("complexFunction split");
		expect(changes).toContain("was 55");
	});

	it("justified 35-49 functions appear in changes with justification", async () => {
		const check = synthComplexityCheck();
		await handleCheckCommand(check, "--fix", stubCtx(cwd));

		const state = await loadRunState(cwd);
		const changes = state?.checks["synth-complexity"].changes;
		expect(changes).toContain("Justified");
		expect(changes).toContain("moderateFunction");
		expect(changes).toContain("critical");
	});

	it("marks check complete after --fix with no errors", async () => {
		const check = synthComplexityCheck();
		await handleCheckCommand(check, "--fix", stubCtx(cwd));

		const state = await loadRunState(cwd);
		expect(state?.checks["synth-complexity"].error).toBeUndefined();
		expect(
			state?.checks["synth-complexity"].phases.find((p) => p.id === "fix")
				?.status,
		).toBe("complete");
	});

	it("gate passes for existing target directory", async () => {
		const check = synthComplexityCheck();
		const gateResult = await check.gate(cwd);
		expect(gateResult).toBeUndefined();
	});

	it("gate fails for nonexistent target", async () => {
		const check = synthComplexityCheck();
		const gateResult = await check.gate(
			"/nonexistent/path/that/does/not/exist",
		);
		expect(gateResult).toContain("does not exist");
	});
});