import { Router, type IRouter } from "express";
import { db } from "@workspace/db";
import {
  scansTable,
  scanFilesTable,
  findingsTable,
  type Scan,
  type ScanFile,
  type Finding,
} from "@workspace/db";
import { eq, desc } from "drizzle-orm";
import {
  ListScansResponse,
  CreateScanBody,
  GetScanParams,
  GetScanResponse,
  DeleteScanParams,
} from "@workspace/api-zod";
import {
  parseZip,
  parseSingleFile,
  parseText,
  deriveScanName,
} from "../lib/skillParser";
import { analyzeSkill, type EngineResult } from "../lib/scanEngine";
import { STATIC_RULES, AI_RULES, type ParsedFile } from "../lib/ruleCatalog";
import { logger } from "../lib/logger";

const router: IRouter = Router();

type CreateScanInput = ReturnType<typeof CreateScanBody.parse>;

export function serializeScan(scan: Scan) {
  return {
    id: scan.id,
    name: scan.name,
    source: scan.source,
    status: scan.status,
    verdict: scan.verdict,
    riskScore: scan.riskScore,
    fileCount: scan.fileCount,
    aiUsed: scan.aiUsed,
    aiError: scan.aiError,
    findingCounts: scan.findingCounts,
    createdAt: scan.createdAt.toISOString(),
  };
}

function serializeFile(f: ScanFile) {
  return {
    path: f.path,
    kind: f.kind,
    language: f.language,
    size: f.size,
  };
}

function serializeFinding(f: Finding) {
  return {
    id: f.id,
    ruleId: f.ruleId,
    axis: f.axis,
    severity: f.severity,
    title: f.title,
    description: f.description,
    remediation: f.remediation,
    file: f.file,
    line: f.line,
    snippet: f.snippet,
    detectedBy: f.detectedBy,
  };
}

function serializeScanDetail(
  scan: Scan,
  files: ScanFile[],
  findings: Finding[],
) {
  return {
    ...serializeScan(scan),
    checkpoints: scan.checkpoints ?? [],
    files: files.map(serializeFile),
    findings: [...findings].sort((a, b) => a.id - b.id).map(serializeFinding),
  };
}

type ParseResult =
  | { ok: true; files: ParsedFile[] }
  | { ok: false; status: number; message: string };

function parseScanInput(input: CreateScanInput): ParseResult {
  try {
    let files: ParsedFile[];
    if (input.source === "zip") {
      if (!input.contentBase64)
        return { ok: false, status: 400, message: "ZIP-Inhalt fehlt." };
      files = parseZip(Buffer.from(input.contentBase64, "base64"));
    } else if (input.source === "file") {
      if (!input.contentBase64)
        return { ok: false, status: 400, message: "Dateiinhalt fehlt." };
      files = [
        parseSingleFile(
          input.filename ?? "datei",
          Buffer.from(input.contentBase64, "base64"),
        ),
      ];
    } else {
      if (!input.text || !input.text.trim())
        return { ok: false, status: 400, message: "Text fehlt." };
      files = [parseText(input.text, input.name ?? "SKILL.md")];
    }
    if (files.length === 0)
      return {
        ok: false,
        status: 400,
        message: "Keine analysierbaren Dateien gefunden.",
      };
    return { ok: true, files };
  } catch (err) {
    logger.error({ err }, "Skill-Parsing fehlgeschlagen");
    return {
      ok: false,
      status: 400,
      message:
        "Das Skill konnte nicht gelesen werden. Bitte prüfen Sie das Format (gültiges ZIP / Textdatei).",
    };
  }
}

async function persistScan(
  input: CreateScanInput,
  name: string,
  files: ParsedFile[],
  result: EngineResult,
): Promise<{ scan: Scan; files: ScanFile[]; findings: Finding[] }> {
  const [scan] = await db
    .insert(scansTable)
    .values({
      name,
      source: input.source,
      status: "completed",
      verdict: result.verdict,
      riskScore: result.riskScore,
      fileCount: files.length,
      aiUsed: result.aiUsed,
      aiError: result.aiError,
      findingCounts: result.counts,
      checkpoints: result.checkpoints,
    })
    .returning();

  let insertedFiles: ScanFile[] = [];
  if (files.length > 0) {
    insertedFiles = await db
      .insert(scanFilesTable)
      .values(
        files.map((f) => ({
          scanId: scan.id,
          path: f.path,
          kind: f.kind,
          language: f.language,
          size: f.size,
        })),
      )
      .returning();
  }

  let insertedFindings: Finding[] = [];
  if (result.findings.length > 0) {
    insertedFindings = await db
      .insert(findingsTable)
      .values(
        result.findings.map((f) => ({
          scanId: scan.id,
          ruleId: f.ruleId,
          axis: f.axis,
          severity: f.severity,
          title: f.title,
          description: f.description,
          remediation: f.remediation,
          file: f.file,
          line: f.line,
          snippet: f.snippet,
          detectedBy: f.detectedBy,
        })),
      )
      .returning();
  }

  return { scan, files: insertedFiles, findings: insertedFindings };
}

router.get("/scans", async (_req, res) => {
  const rows = await db
    .select()
    .from(scansTable)
    .orderBy(desc(scansTable.createdAt));
  res.json(ListScansResponse.parse(rows.map(serializeScan)));
});

router.post("/scans", async (req, res) => {
  const parsed = CreateScanBody.safeParse(req.body);
  if (!parsed.success) {
    return res
      .status(400)
      .json({ message: "Ungültige Eingabe", details: parsed.error.issues });
  }
  const input = parsed.data;

  const parseResult = parseScanInput(input);
  if (!parseResult.ok) {
    return res.status(parseResult.status).json({ message: parseResult.message });
  }
  const files = parseResult.files;

  const name = input.name?.trim() || deriveScanName(files, "Unbenanntes Skill");
  const result = await analyzeSkill(files, input.useAi);
  const { scan, files: insertedFiles, findings } = await persistScan(
    input,
    name,
    files,
    result,
  );

  return res
    .status(201)
    .json(GetScanResponse.parse(serializeScanDetail(scan, insertedFiles, findings)));
});

const STREAM_PACING_MS = 80;
const delay = (ms: number) => new Promise<void>((resolve) => setTimeout(resolve, ms));

router.post("/scans/stream", async (req, res) => {
  const parsed = CreateScanBody.safeParse(req.body);
  if (!parsed.success) {
    res
      .status(400)
      .json({ message: "Ungültige Eingabe", details: parsed.error.issues });
    return;
  }
  const input = parsed.data;

  const parseResult = parseScanInput(input);
  if (!parseResult.ok) {
    res.status(parseResult.status).json({ message: parseResult.message });
    return;
  }
  const files = parseResult.files;
  const name = input.name?.trim() || deriveScanName(files, "Unbenanntes Skill");

  res.status(200);
  res.setHeader("Content-Type", "application/x-ndjson; charset=utf-8");
  res.setHeader("Cache-Control", "no-cache, no-transform");
  res.setHeader("X-Accel-Buffering", "no");
  res.setHeader("Connection", "keep-alive");
  res.flushHeaders();

  // Detect a genuine client disconnect. NOTE: do NOT use req.on("close") here —
  // for a POST it fires as soon as the request body is consumed, not on abort.
  // res "close" before writableFinished means the client went away.
  let aborted = false;
  res.on("close", () => {
    if (!res.writableFinished) aborted = true;
  });

  const write = (obj: unknown) => {
    if (aborted || res.writableEnded) return;
    res.write(JSON.stringify(obj) + "\n");
  };

  write({
    type: "start",
    name,
    fileCount: files.length,
    totalChecks: STATIC_RULES.length + (input.useAi ? AI_RULES.length : 0),
  });

  let cumulative = 0;
  try {
    const result = await analyzeSkill(files, input.useAi, async (event) => {
      if (event.type === "ai-start") {
        write({ type: "ai-start" });
        return;
      }
      cumulative += event.checkpoint.scoreDelta;
      write({
        type: "checkpoint",
        checkpoint: event.checkpoint,
        runningScore: Math.min(100, cumulative),
      });
      if (!aborted) await delay(STREAM_PACING_MS);
    });

    const { scan } = await persistScan(input, name, files, result);

    write({
      type: "done",
      scanId: scan.id,
      riskScore: result.riskScore,
      verdict: result.verdict,
      findingCounts: result.counts,
      aiUsed: result.aiUsed,
      aiError: result.aiError,
    });
    if (!aborted && !res.writableEnded) res.end();
  } catch (err) {
    logger.error({ err }, "Streaming-Scan fehlgeschlagen");
    write({ type: "error", message: "Die Analyse ist fehlgeschlagen." });
    if (!aborted && !res.writableEnded) res.end();
  }
});

router.get("/scans/:id", async (req, res) => {
  const params = GetScanParams.safeParse(req.params);
  if (!params.success)
    return res.status(400).json({ message: "Ungültige ID" });

  const [scan] = await db
    .select()
    .from(scansTable)
    .where(eq(scansTable.id, params.data.id));
  if (!scan) return res.status(404).json({ message: "Scan nicht gefunden" });

  const files = await db
    .select()
    .from(scanFilesTable)
    .where(eq(scanFilesTable.scanId, scan.id));
  const findings = await db
    .select()
    .from(findingsTable)
    .where(eq(findingsTable.scanId, scan.id))
    .orderBy(findingsTable.id);

  return res.json(GetScanResponse.parse(serializeScanDetail(scan, files, findings)));
});

router.delete("/scans/:id", async (req, res) => {
  const params = DeleteScanParams.safeParse(req.params);
  if (!params.success)
    return res.status(400).json({ message: "Ungültige ID" });
  await db.delete(scansTable).where(eq(scansTable.id, params.data.id));
  return res.status(204).send();
});

export default router;