// Kimi-architect check — second-pass senior architectural review using
// kimi-for-coding (Kimi K2.6) via /v1/chat provider=kimi.
//
// Runs AFTER the deepseek inference check (N=3 consensus) and the
// static/kb_query checks. Reads their findings as context and asks Kimi
// "what did everyone else miss?" — complementing the cheap-consensus
// voting with a sparse senior pass that catches load-bearing issues
// (compile errors, false telemetry, schema bypasses, etc.) which the
// voting structure can't see.
//
// Why Kimi here and not in the inner inference loop:
// - Cost: ~3min wall-clock per call vs ~30s for deepseek consensus.
// - TOS: api.kimi.com is User-Agent-gated (see crates/gateway/src/v1/
//   kimi.rs); cost-bounded calls only.
// - Value: experiment 2026-04-27 showed 7/7 grounding rate with full
//   files vs ~50% on truncated input. Best as a sparse complement, not
//   a replacement.
//
// Failure-isolated: any Kimi error returns a single info-level Finding
// "kimi_architect skipped — <reason>" so the existing audit pipeline
// is never blocked by a Kimi outage / TOS revocation / 429.
//
// Cost cap: if a kimi_verdicts/<pr>-<sha>.json file exists less than 24h
// old, return cached findings without calling upstream. New commits
// produce new SHAs so this is per-head, not per-day.
//
// Off by default: caller checks LH_AUDITOR_KIMI=1 before invoking.

import { readFile, writeFile, mkdir, appendFile, stat, realpath } from "node:fs/promises";
import { existsSync, realpathSync } from "node:fs";
import { dirname, join, resolve } from "node:path";
import type { Finding, CheckKind } from "../types.ts";

const GATEWAY = process.env.LH_GATEWAY_URL ?? "http://localhost:3100";
const KIMI_VERDICTS_DIR = "/home/profit/lakehouse/data/_auditor/kimi_verdicts";
const KIMI_AUDITS_JSONL = "/home/profit/lakehouse/data/_kb/kimi_audits.jsonl";
const REPO_ROOT = "/home/profit/lakehouse";
// Canonicalize at module load — REPO_ROOT itself may be a symlink in
// some environments (e.g. /home/profit is a bind-mount). Computing
// once at startup means the per-finding grounding loop can compare
// realpath(target) against this stable anchor.
const REPO_ROOT_REAL = (() => {
  try { return realpathSync(REPO_ROOT); }
  catch { return REPO_ROOT; }
})();
// 15 min budget. Bun's fetch has an intrinsic ~300s limit that our
// AbortController + setTimeout combo could not override; we use curl
// via Bun.spawn instead (callKimi below). Curl honors -m for max
// transfer time without a hard intrinsic ceiling.
const CALL_TIMEOUT_MS = 900_000;
const CACHE_TTL_MS = 24 * 60 * 60 * 1000;
const MAX_DIFF_CHARS = 180_000;
const MAX_PRIOR_FINDINGS = 50;
// Default provider/model = ollama_cloud/kimi-k2.6. Pre-2026-04-27 we
// went direct to api.kimi.com, but Ollama Cloud Pro now exposes the
// same model legitimately, so we route there to avoid User-Agent
// gating. The api.kimi.com path (provider=kimi) remains wired in the
// gateway as a fallback for when Ollama Cloud is upstream-broken.
const KIMI_PROVIDER = process.env.LH_AUDITOR_KIMI_PROVIDER ?? "ollama_cloud";
const KIMI_MODEL = process.env.LH_AUDITOR_KIMI_MODEL ?? "kimi-k2.6";
// Cross-lineage alternation. 2026-04-27 J's call: Opus is too
// expensive to auto-fire (~$0.30/audit). Kimi K2.6 via Go-sub is
// effectively free; Haiku 4.5 via Zen is ~$0.04. Alternate between
// them so we get cross-lineage signal (Moonshot vs Anthropic) on
// every PR's audit history without burning the budget.
//
// Default: Kimi K2.6 on even audits, Haiku 4.5 on odd. Each PR's
// audits flip between vendors as new SHAs come in.
//
// Frontier models (Opus 4.7, GPT-5.5, Gemini 3.1) are NOT in the
// auto path. Operator hands distilled findings to a frontier model
// manually when high-leverage decisions need it. Removing Opus from
// auto-promotion saves ~$1-3/day on the daemon at our cadence.
//
// Override the alternation entirely with LH_AUDITOR_KIMI_MODEL
// (forces one model regardless of audit count); set
// LH_AUDITOR_KIMI_ALT_MODEL to the alternate.
const ALT_MODEL = process.env.LH_AUDITOR_KIMI_ALT_MODEL ?? "claude-haiku-4-5";
const ALT_PROVIDER = process.env.LH_AUDITOR_KIMI_ALT_PROVIDER ?? "opencode";
const FORCE_DEFAULT = process.env.LH_AUDITOR_KIMI_MODEL !== undefined && process.env.LH_AUDITOR_KIMI_MODEL !== "";

function selectModel(diffLen: number, auditIndex: number = 0): { provider: string; model: string; promoted: boolean } {
  // Operator override — env-pinned model wins.
  if (FORCE_DEFAULT) {
    return { provider: KIMI_PROVIDER, model: KIMI_MODEL, promoted: false };
  }
  // Alternate Kimi (default, even index) ↔ Haiku (alt, odd index).
  // diffLen kept in the signature for future "big diff → Haiku
  // anyway" logic; not used yet so we don't auto-burn on big PRs.
  void diffLen;
  if (auditIndex % 2 === 1) {
    return { provider: ALT_PROVIDER, model: ALT_MODEL, promoted: true };
  }
  return { provider: KIMI_PROVIDER, model: KIMI_MODEL, promoted: false };
}
// Model-aware max_tokens. Different upstream APIs cap at different
// limits and reject requests that exceed them:
//   - Anthropic Opus 4.x: 32K output (with extended-output header)
//   - Anthropic Haiku 4.5: 8K output
//   - Kimi K2.6 (reasoning): 128K — needs headroom because
//     reasoning_content counts against the budget
//   - Default: 16K, conservative middle ground
//
// 2026-04-27 BLOCK from Opus self-audit: the prior single-default of
// 128K worked silently (Anthropic clamps server-side) but was
// technically invalid. Per-model caps make it explicit. Override via
// LH_AUDITOR_KIMI_MAX_TOKENS to force a value (also fixes the empty-
// env Number("") -> 0 trap by using `||` not `??`).
const MAX_TOKENS_OVERRIDE = Number(process.env.LH_AUDITOR_KIMI_MAX_TOKENS) || 0;
function maxTokensFor(model: string): number {
  if (MAX_TOKENS_OVERRIDE > 0) return MAX_TOKENS_OVERRIDE;
  if (model.startsWith("claude-opus")) return 32_000;
  if (model.startsWith("claude-haiku") || model.startsWith("claude-sonnet")) return 8_192;
  if (model.startsWith("kimi-")) return 128_000;
  if (model.startsWith("gpt-5") || model.startsWith("o1") || model.startsWith("o3") || model.startsWith("o4")) return 32_000;
  return 16_000;
}

export interface KimiArchitectContext {
  pr_number: number;
  head_sha: string;
}

interface KimiVerdictFile {
  pr_number: number;
  head_sha: string;
  cached_at: string;
  model: string;
  latency_ms: number;
  finish_reason: string;
  usage: { prompt_tokens: number; completion_tokens: number; total_tokens: number };
  raw_content: string;
  findings: Finding[];
  grounding: { total: number; verified: number; rate: number };
}

export async function runKimiArchitectCheck(
  diff: string,
  priorFindings: Finding[],
  ctx: KimiArchitectContext,
): Promise<Finding[]> {
  const cachePath = join(KIMI_VERDICTS_DIR, `${ctx.pr_number}-${ctx.head_sha.slice(0, 12)}.json`);
  const outageSentinel = `${cachePath}.outage`;
  const OUTAGE_TTL_MS = 10 * 60 * 1000;

  // Outage negative-cache — if upstream failed within OUTAGE_TTL_MS,
  // skip this audit and return immediately. Prevents the daemon from
  // hammering a downed Kimi/Anthropic upstream every 90s.
  if (existsSync(outageSentinel)) {
    try {
      const s = await stat(outageSentinel);
      if (Date.now() - s.mtimeMs < OUTAGE_TTL_MS) {
        const note = JSON.parse(await readFile(outageSentinel, "utf8"));
        return [skipFinding(`upstream still down (cached ${Math.round((Date.now() - s.mtimeMs) / 1000)}s ago): ${String(note.reason).slice(0, 160)}`)];
      }
    } catch { /* malformed sentinel — fall through to fresh call */ }
  }

  // Cost cap — return cached findings if a verdict for this exact head
  // SHA was generated within the TTL.
  const cached = await loadCachedVerdict(cachePath);
  if (cached) {
    return cached.findings.length > 0
      ? cached.findings
      : [{ check: "kimi_architect" as CheckKind, severity: "info", summary: "kimi_architect cached — 0 findings", evidence: [`cache: ${cachePath}`] }];
  }

  // Alternate model based on how many audits this PR has had — gives
  // cross-lineage signal (Kimi/Moonshot ↔ Haiku/Anthropic) on every
  // PR's audit history. Count is derived from existing kimi_verdicts
  // files for this PR; cheap O(N_PRs) directory read.
  let auditIndex = 0;
  try {
    const dir = "/home/profit/lakehouse/data/_auditor/kimi_verdicts";
    if (existsSync(dir)) {
      const all = require("node:fs").readdirSync(dir) as string[];
      auditIndex = all.filter((f) => f.startsWith(`${ctx.pr_number}-`)).length;
    }
  } catch { /* default 0 — Kimi */ }

  const selected = selectModel(diff.length, auditIndex);
  let response: { content: string; usage: any; finish_reason: string; latency_ms: number };
  try {
    response = await callKimi(buildPrompt(diff, priorFindings, ctx), selected.provider, selected.model);
  } catch (e) {
    // Negative-cache for 10 min on outage (caught 2026-04-27 by Opus
    // self-audit): without this, every audit cycle within the 24h
    // TTL re-calls upstream while it's still down. Use a sentinel
    // file with mtime check rather than persisting a verdict so the
    // happy-path cache reader doesn't have to special-case it.
    const sentinel = `${cachePath}.outage`;
    try { await writeFile(sentinel, JSON.stringify({ at: new Date().toISOString(), reason: (e as Error).message.slice(0, 200) })); } catch {}
    return [skipFinding(`kimi call failed (${selected.model}): ${(e as Error).message.slice(0, 200)}`)];
  }

  const findings = parseFindings(response.content);
  const grounding = await computeGrounding(findings);

  const verdict: KimiVerdictFile = {
    pr_number: ctx.pr_number,
    head_sha: ctx.head_sha,
    cached_at: new Date().toISOString(),
    model: selected.model,
    latency_ms: response.latency_ms,
    finish_reason: response.finish_reason,
    usage: {
      prompt_tokens: response.usage?.prompt_tokens ?? 0,
      completion_tokens: response.usage?.completion_tokens ?? 0,
      total_tokens: response.usage?.total_tokens ?? 0,
    },
    raw_content: response.content,
    findings,
    grounding,
  };

  // Cache-poisoning guard (caught 2026-04-27 by Opus self-audit):
  // when parseFindings returns 0 findings (Kimi rambled, prompt too
  // big, or the markdown shape changed and our regex missed every
  // block), persisting the empty verdict short-circuits all future
  // audits in the 24h TTL window with a useless cached "0 findings"
  // result. Better to leave no cache and re-call upstream next time.
  // Always append metrics — observability shouldn't depend on whether
  // findings parsed.
  await appendMetrics(verdict);
  if (findings.length > 0) {
    await persistVerdict(cachePath, verdict);
    return findings;
  }
  return [{
    check: "kimi_architect" as CheckKind,
    severity: "info",
    summary: `kimi_architect produced 0 ranked findings (${response.finish_reason}, ${verdict.usage.completion_tokens} tokens) — not cached`,
    evidence: [`raw saved (no cache): see kimi_audits.jsonl ${verdict.cached_at}`],
  }];
}

async function loadCachedVerdict(path: string): Promise<KimiVerdictFile | null> {
  if (!existsSync(path)) return null;
  try {
    const s = await stat(path);
    if (Date.now() - s.mtimeMs > CACHE_TTL_MS) return null;
    return JSON.parse(await readFile(path, "utf8")) as KimiVerdictFile;
  } catch { return null; }
}

function buildPrompt(diff: string, priorFindings: Finding[], ctx: KimiArchitectContext): string {
  const truncatedDiff = diff.length > MAX_DIFF_CHARS
    ? diff.slice(0, MAX_DIFF_CHARS) + `\n\n... [truncated; original diff was ${diff.length} chars]`
    : diff;

  const priorBlock = priorFindings
    .filter(f => f.severity !== "info")
    .slice(0, MAX_PRIOR_FINDINGS)
    .map(f => `- [${f.check}/${f.severity}] ${f.summary}${f.evidence?.[0] ? ` — ${f.evidence[0].slice(0, 160)}` : ""}`)
    .join("\n");

  return `You are a senior software architect doing a second-pass review on PR #${ctx.pr_number} (head ${ctx.head_sha.slice(0, 12)}). The team's automated auditor (deepseek-v3.1:671b, N=3 consensus) already produced findings. Your job is NOT to repeat what they found — your job is to catch what their voting structure CAN'T see: compile errors, type-system bypasses, false telemetry, silent determinism leaks, schema-bypass anti-patterns, load-bearing assumptions that look fine line-by-line.

GROUNDING RULES (non-negotiable):
- Cite file:line for EVERY finding. Lines you cite must actually contain what you claim. Confabulating a finding wastes more time than missing one.
- If the diff is truncated and you can't verify a claim, say "diff-truncated, can't verify" — DO NOT guess.
- Distinguish architectural concerns (no specific line) from concrete bugs (specific line). Don't dress one as the other.

PRIOR FINDINGS FROM DEEPSEEK CONSENSUS (do not repeat these):
${priorBlock || "(none)"}

OUTPUT FORMAT (markdown):
- ## Verdict (one sentence)
- ## Findings (5-10 items, each formatted EXACTLY as below)

For each finding use this exact shape so a parser can lift them:

### F1: <one-line summary>
- **Severity:** block | warn | info
- **File:** path/to/file.ext:LINE
- **Rationale:** one or two sentences

THE DIFF:

${truncatedDiff}
`;
}

async function callKimi(prompt: string, provider: string, model: string): Promise<{ content: string; usage: any; finish_reason: string; latency_ms: number }> {
  const t0 = Date.now();
  const body = JSON.stringify({
    provider,
    model,
    messages: [{ role: "user", content: prompt }],
    max_tokens: maxTokensFor(model),
    temperature: 0.2,
  });
  // curl via Bun.spawn — bypasses Bun fetch's ~300s intrinsic ceiling.
  // -m sets the max transfer time honored end-to-end. Body is piped via
  // stdin to avoid argv length limits on big audit prompts (~50K+ tokens).
  const proc = Bun.spawn({
    cmd: [
      "curl", "-sS", "-X", "POST",
      "-m", String(Math.ceil(CALL_TIMEOUT_MS / 1000)),
      "-H", "content-type: application/json",
      "--data-binary", "@-",
      `${GATEWAY}/v1/chat`,
    ],
    stdin: "pipe",
    stdout: "pipe",
    stderr: "pipe",
  });
  proc.stdin.write(body);
  await proc.stdin.end();
  const [stdout, stderr, exitCode] = await Promise.all([
    new Response(proc.stdout).text(),
    new Response(proc.stderr).text(),
    proc.exited,
  ]);
  if (exitCode !== 0) {
    throw new Error(`curl exit ${exitCode}: ${stderr.slice(0, 300)}`);
  }
  let j: any;
  try { j = JSON.parse(stdout); }
  catch (e) {
    throw new Error(`bad response (${stdout.length} bytes): ${stdout.slice(0, 300)}`);
  }
  if (j.error || !j.choices) {
    throw new Error(`gateway error: ${JSON.stringify(j).slice(0, 300)}`);
  }
  return {
    content: j.choices?.[0]?.message?.content ?? "",
    usage: j.usage ?? {},
    finish_reason: j.choices?.[0]?.finish_reason ?? "unknown",
    latency_ms: Date.now() - t0,
  };
}

// Parse Kimi's markdown into Finding[]. Format expected (per buildPrompt):
//   ### F<N>: <summary>
//   - **Severity:** block | warn | info
//   - **File:** path:line
//   - **Rationale:** ...
function parseFindings(content: string): Finding[] {
  const findings: Finding[] = [];
  const blocks = content.split(/^###\s+F\d+:\s*/m).slice(1);
  for (const block of blocks) {
    const summary = (block.split("\n")[0] ?? "").trim();
    if (!summary) continue;
    const sev = /\*\*Severity:\*\*\s*(block|warn|info)/i.exec(block)?.[1]?.toLowerCase();
    const fileLine = /\*\*File:\*\*\s*(\S+)/i.exec(block)?.[1] ?? "unknown";
    const rationale = /\*\*Rationale:\*\*\s*([\s\S]+?)(?=\n###|\n\*\*|$)/i.exec(block)?.[1]?.trim() ?? "";
    const severity: Finding["severity"] = sev === "block" ? "block" : sev === "warn" ? "warn" : "info";
    findings.push({
      check: "kimi_architect" as CheckKind,
      severity,
      summary: summary.slice(0, 240),
      evidence: [fileLine, rationale.slice(0, 360)].filter(Boolean),
    });
  }
  return findings;
}

// For each finding's cited file:line, grep the actual file to verify
// the line exists. Returns total + verified counts; per-finding metadata
// is appended into the evidence array so the reader can see which
// citations were verified.
async function computeGrounding(findings: Finding[]): Promise<{ total: number; verified: number; rate: number }> {
  // readFile (async) instead of readFileSync — caught 2026-04-27 by
  // Kimi's self-audit. Sync I/O in an async fn blocks the event loop
  // for every cited file; doesn't matter at 10 findings, would matter
  // at 100+.
  const checks = await Promise.all(findings.map(async (f) => {
    const cite = f.evidence[0] ?? "";
    const m = /^(\S+?):(\d+)/.exec(cite);
    if (!m) return false;
    const [, relpath, lineStr] = m;
    const line = Number(lineStr);
    if (!line || !relpath) return false;

    // Path-traversal guard, two-layer (caught 2026-04-27 by Kimi
    // self-audits on dd77632 then 2d9cb12).
    //
    // Layer 1 (lexical): resolve() normalizes `..` segments. Refuse
    // any path that doesn't anchor under REPO_ROOT.
    //
    // Layer 2 (symlink): even if the lexical path is anchored, it
    // could be a symlink whose target escapes. realpath() resolves
    // symlinks; compare the real path against REPO_ROOT_REAL.
    //
    // Both layers exist because attackers might bypass either alone:
    // raw `../etc/passwd` triggers layer 1; a planted symlink at
    // ./safe-looking-name → /etc/passwd triggers layer 2.
    const abs = resolve(REPO_ROOT, relpath);
    if (!abs.startsWith(REPO_ROOT + "/") && abs !== REPO_ROOT) {
      f.evidence.push(`[grounding: path escapes repo root, refusing]`);
      return false;
    }

    if (!existsSync(abs)) {
      f.evidence.push("[grounding: file not found]");
      return false;
    }
    try {
      // Symlink-resolution check before any read. realpath() throws
      // if the file doesn't exist; existsSync above shields the
      // common case but a TOCTOU race could still error here — the
      // outer catch handles it.
      const realPath = await realpath(abs);
      if (!realPath.startsWith(REPO_ROOT_REAL + "/") && realPath !== REPO_ROOT_REAL) {
        f.evidence.push(`[grounding: symlink target escapes repo root, refusing]`);
        return false;
      }
      const lines = (await readFile(realPath, "utf8")).split("\n");
      if (line < 1 || line > lines.length) {
        f.evidence.push(`[grounding: line ${line} > EOF (${lines.length})]`);
        return false;
      }
      f.evidence.push(`[grounding: verified at ${relpath}:${line}]`);
      return true;
    } catch (e) {
      f.evidence.push(`[grounding: read failed: ${(e as Error).message.slice(0, 80)}]`);
      return false;
    }
  }));
  const verified = checks.filter(Boolean).length;
  const total = findings.length;
  return { total, verified, rate: total === 0 ? 0 : verified / total };
}

async function persistVerdict(path: string, v: KimiVerdictFile): Promise<void> {
  await mkdir(KIMI_VERDICTS_DIR, { recursive: true });
  await writeFile(path, JSON.stringify(v, null, 2));
}

async function appendMetrics(v: KimiVerdictFile): Promise<void> {
  // dirname() instead of join(path, "..") — caught 2026-04-27 by both
  // Haiku and Opus self-audits. The "/.." idiom resolves correctly
  // via Node path normalization but is non-idiomatic + breaks if the
  // path ever has trailing dots.
  await mkdir(dirname(KIMI_AUDITS_JSONL), { recursive: true });
  await appendFile(KIMI_AUDITS_JSONL, JSON.stringify({
    pr_number: v.pr_number,
    head_sha: v.head_sha,
    audited_at: v.cached_at,
    model: v.model,
    latency_ms: v.latency_ms,
    finish_reason: v.finish_reason,
    prompt_tokens: v.usage.prompt_tokens,
    completion_tokens: v.usage.completion_tokens,
    findings_total: v.findings.length,
    findings_block: v.findings.filter(f => f.severity === "block").length,
    findings_warn: v.findings.filter(f => f.severity === "warn").length,
    grounding_verified: v.grounding.verified,
    grounding_rate: Number(v.grounding.rate.toFixed(3)),
  }) + "\n");
}

function skipFinding(why: string): Finding {
  return {
    check: "kimi_architect" as CheckKind,
    severity: "info",
    summary: `kimi_architect skipped — ${why}`,
    evidence: [why],
  };
}