/**
 * Smoke tests for the systemPromptMode feature.
 * Tests: frontmatter parsing, identity routing, CLI flag generation.
 */
import { mkdtempSync, writeFileSync, rmSync, mkdirSync, readFileSync, existsSync } from "node:fs";
import { join } from "node:path";
import { tmpdir } from "node:os";

let passed = 0;
let failed = 0;

function assert(condition: boolean, msg: string) {
  if (condition) {
    console.log(`  ✅ ${msg}`);
    passed++;
  } else {
    console.log(`  ❌ ${msg}`);
    failed++;
  }
}

// --- Extracted logic under test ---

function parseFrontmatter(content: string) {
  const match = content.match(/^---\n([\s\S]*?)\n---/);
  if (!match) return null;
  const frontmatter = match[1];
  const get = (key: string) => {
    const m = frontmatter.match(new RegExp(`^${key}:\\s*(.+)$`, "m"));
    return m ? m[1].trim() : undefined;
  };
  const body = content.replace(/^---\n[\s\S]*?\n---\n*/, "").trim();
  const spm = get("system-prompt");
  return {
    systemPromptMode: spm === "replace" ? "replace" : spm === "append" ? "append" : undefined,
    body: body || undefined,
  };
}

function simulateRouting(
  agentBody: string | undefined,
  systemPromptMode: "append" | "replace" | undefined,
  paramSystemPrompt: string | undefined,
) {
  const identity = agentBody ?? paramSystemPrompt ?? null;
  const identityInSystemPrompt = systemPromptMode && identity;
  const roleBlock = identity && !identityInSystemPrompt ? `\n\n${identity}` : "";

  let cliFlag: string | null = null;
  if (identityInSystemPrompt && identity) {
    cliFlag = systemPromptMode === "replace" ? "--system-prompt" : "--append-system-prompt";
  }

  return { roleBlock, cliFlag, identityInSystemPrompt: !!identityInSystemPrompt };
}

// --- Fixtures ---

const AGENT_REPLACE = `---
model: anthropic/claude-sonnet-4-20250514
system-prompt: replace
auto-exit: true
---

You are a specialized agent.`;

const AGENT_APPEND = `---
model: anthropic/claude-sonnet-4-20250514
system-prompt: append
---

You are an appended identity.`;

const AGENT_DEFAULT = `---
model: anthropic/claude-sonnet-4-20250514
---

You are a default agent.`;

const AGENT_INVALID = `---
model: anthropic/claude-sonnet-4-20250514
system-prompt: foobar
---

Body here.`;

// --- Test 1: Frontmatter parsing ---
console.log("\n🧪 Frontmatter parsing of system-prompt field");

const r1 = parseFrontmatter(AGENT_REPLACE)!;
assert(r1.systemPromptMode === "replace", "system-prompt: replace → mode is 'replace'");
assert(r1.body === "You are a specialized agent.", "body extracted correctly");

const r2 = parseFrontmatter(AGENT_APPEND)!;
assert(r2.systemPromptMode === "append", "system-prompt: append → mode is 'append'");

const r3 = parseFrontmatter(AGENT_DEFAULT)!;
assert(r3.systemPromptMode === undefined, "no system-prompt field → mode is undefined");

const r4 = parseFrontmatter(AGENT_INVALID)!;
assert(r4.systemPromptMode === undefined, "system-prompt: foobar → mode is undefined (ignored)");

// --- Test 2: Identity routing ---
console.log("\n🧪 Identity routing (system prompt vs user message)");

const s1 = simulateRouting("You are X.", "replace", undefined);
assert(s1.roleBlock === "", "replace mode: roleBlock empty (not in task)");
assert(s1.cliFlag === "--system-prompt", "replace mode: uses --system-prompt flag");

const s2 = simulateRouting("You are X.", "append", undefined);
assert(s2.roleBlock === "", "append mode: roleBlock empty (not in task)");
assert(s2.cliFlag === "--append-system-prompt", "append mode: uses --append-system-prompt flag");

const s3 = simulateRouting("You are X.", undefined, undefined);
assert(s3.roleBlock === "\n\nYou are X.", "no mode: roleBlock contains identity");
assert(s3.cliFlag === null, "no mode: no CLI flag");

const s4 = simulateRouting(undefined, undefined, undefined);
assert(s4.roleBlock === "", "no identity: roleBlock empty");
assert(s4.cliFlag === null, "no identity: no CLI flag");

const s5 = simulateRouting(undefined, "replace", undefined);
assert(s5.roleBlock === "", "mode set but no body: roleBlock empty");
assert(s5.cliFlag === null, "mode set but no body: no CLI flag");

const s6 = simulateRouting(undefined, "replace", "Param identity");
assert(s6.cliFlag === "--system-prompt", "mode + param systemPrompt: uses CLI flag");
assert(s6.roleBlock === "", "mode + param systemPrompt: roleBlock empty");

// --- Test 3: End-to-end with temp agent files ---
console.log("\n🧪 End-to-end with temp agent files");

const tmpDir = mkdtempSync(join(tmpdir(), "pi-test-spm-"));
const agentsDir = join(tmpDir, ".pi", "agents");
mkdirSync(agentsDir, { recursive: true });

writeFileSync(join(agentsDir, "test-replace.md"), AGENT_REPLACE);
writeFileSync(join(agentsDir, "test-append.md"), AGENT_APPEND);
writeFileSync(join(agentsDir, "test-default.md"), AGENT_DEFAULT);

function loadFromDir(name: string) {
  const p = join(agentsDir, `${name}.md`);
  if (!existsSync(p)) return null;
  return parseFrontmatter(readFileSync(p, "utf8"));
}

const t1 = loadFromDir("test-replace")!;
assert(t1.systemPromptMode === "replace", "file test-replace.md → replace mode");
assert(t1.body === "You are a specialized agent.", "file test-replace.md → body correct");

const t2 = loadFromDir("test-append")!;
assert(t2.systemPromptMode === "append", "file test-append.md → append mode");

const t3 = loadFromDir("test-default")!;
assert(t3.systemPromptMode === undefined, "file test-default.md → no mode");

rmSync(tmpDir, { recursive: true });

// --- Summary ---
console.log(`\n${"=".repeat(40)}`);
console.log(`Results: ${passed} passed, ${failed} failed`);
if (failed > 0) process.exit(1);
console.log("All tests passed! ✅\n");