/**
 * DOT / FMCSA motor carrier compliance lookup.
 *
 * GET /api/v1/dot/lookup?dot=1234567
 * GET /api/v1/dot/search?name=Acme+Trucking
 *
 * Combines local census data with live FMCSA QCMobile API for
 * real-time compliance status checks.
 */

import { Router } from "express";
import { pool } from "../db.js";

const router = Router();
const FMCSA_API_KEY = process.env.FMCSA_API_KEY || "";
const FMCSA_BASE = "https://mobile.fmcsa.dot.gov/qc/services/carriers";

// ── Helpers ─────────────────────────────────────────────────────────

async function fmcsaFetch(path: string): Promise<any> {
  if (!FMCSA_API_KEY) return null;
  try {
    const url = `${FMCSA_BASE}/${path}${path.includes("?") ? "&" : "?"}webKey=${FMCSA_API_KEY}`;
    const resp = await fetch(url, {
      signal: AbortSignal.timeout(10000),
      headers: { "Accept": "application/json" },
    });
    if (!resp.ok) return null;
    return await resp.json();
  } catch {
    return null;
  }
}

type CheckStatus = "green" | "yellow" | "red" | "unknown";

interface ComplianceCheck {
  id: string;
  label: string;
  status: CheckStatus;
  detail: string;
  action_url?: string | null;
}

function twoYearsAgo(): Date {
  const d = new Date();
  d.setFullYear(d.getFullYear() - 2);
  return d;
}

// ── DOT Lookup ──────────────────────────────────────────────────────

router.get("/api/v1/dot/lookup", async (req, res) => {
  const rawDot = (req.query.dot as string || "").trim().replace(/\D/g, "");
  if (!rawDot) {
    res.status(400).json({ error: "Provide a DOT number." });
    return;
  }

  try {
    // 1. Local census data
    const local = await pool.query(
      "SELECT * FROM fmcsa_carriers WHERE dot_number = $1",
      [rawDot],
    );
    const census = local.rows[0] || null;

    // 2. Live FMCSA API
    const snapshot = await fmcsaFetch(rawDot);
    const carrier = snapshot?.content?.carrier || null;

    // 3. Authority check
    const authorityData = await fmcsaFetch(`${rawDot}/authority`);
    const authorities = (authorityData?.content || []).map((a: any) => a.carrierAuthority);

    if (!census && !carrier) {
      res.status(404).json({ error: `DOT# ${rawDot} not found.` });
      return;
    }

    // Build compliance checks
    const checks: ComplianceCheck[] = [];
    const name = carrier?.legalName || census?.legal_name || "Unknown";
    const dba = carrier?.dbaName || census?.dba_name || "";

    // ── Check 1: Operating Status ──
    if (carrier) {
      const allowed = carrier.allowedToOperate === "Y";
      const status = carrier.statusCode;
      checks.push({
        id: "operating_status",
        label: "Operating Status",
        status: allowed ? "green" : "red",
        detail: allowed
          ? `Authorized to operate. Status: ${status === "A" ? "Active" : status}.`
          : `NOT authorized to operate. Status: ${status}. This carrier cannot legally operate.`,
      });
    }

    // ── Check 2: MCS-150 Biennial Update ──
    {
      const outdated = carrier?.mcs150Outdated === "Y";
      const mcs150Date = census?.mcs150_parsed || null;
      const isOverdue = mcs150Date ? new Date(mcs150Date) < twoYearsAgo() : null;

      if (outdated || isOverdue) {
        checks.push({
          id: "mcs150",
          label: "MCS-150 Biennial Update",
          status: "red",
          detail: `OVERDUE — last filed ${mcs150Date || "unknown date"}. The MCS-150 must be updated every 2 years. `
            + `Failure to update can result in USDOT deactivation and fines up to $1,000/day (capped at $10,000). `
            + `File at: https://safer.fmcsa.dot.gov/CompanyUpdateSearch.aspx`,
          action_url: "https://safer.fmcsa.dot.gov/CompanyUpdateSearch.aspx",
        });
      } else if (mcs150Date) {
        checks.push({
          id: "mcs150",
          label: "MCS-150 Biennial Update",
          status: "green",
          detail: `Current — last filed ${mcs150Date}.`,
        });
      } else {
        checks.push({
          id: "mcs150",
          label: "MCS-150 Biennial Update",
          status: "unknown",
          detail: "Filing date not available. Verify at SAFER.",
        });
      }
    }

    // ── Check 3: Insurance ──
    if (carrier) {
      const bipdRequired = carrier.bipdInsuranceRequired === "Y";
      const bipdOnFile = carrier.bipdInsuranceOnFile !== null && carrier.bipdInsuranceOnFile !== "0";
      const cargoRequired = carrier.cargoInsuranceRequired === "Y";
      const cargoOnFile = carrier.cargoInsuranceOnFile !== null && carrier.cargoInsuranceOnFile !== "0";
      const bondRequired = carrier.bondInsuranceRequired === "Y";
      const bondOnFile = carrier.bondInsuranceOnFile !== null && carrier.bondInsuranceOnFile !== "0";

      const issues: string[] = [];
      if (bipdRequired && !bipdOnFile) issues.push("Liability (BIPD) insurance required but not on file");
      if (cargoRequired && !cargoOnFile) issues.push("Cargo insurance required but not on file");
      if (bondRequired && !bondOnFile) issues.push("Bond/trust fund required but not on file");

      if (issues.length > 0) {
        checks.push({
          id: "insurance",
          label: "Insurance Filing",
          status: "red",
          detail: issues.join(". ") + ". Operating without required insurance can result in immediate out-of-service order and operating authority revocation.",
        });
      } else if (bipdRequired || cargoRequired) {
        checks.push({
          id: "insurance",
          label: "Insurance Filing",
          status: "green",
          detail: "Required insurance is on file with FMCSA.",
        });
      }
    }

    // ── Check 4: Safety Rating ──
    if (carrier && carrier.safetyRating) {
      const rating = carrier.safetyRating;
      const ratingDate = carrier.safetyRatingDate || "";
      const ratingMap: Record<string, { status: CheckStatus; label: string }> = {
        S: { status: "green", label: "Satisfactory" },
        C: { status: "yellow", label: "Conditional" },
        U: { status: "red", label: "Unsatisfactory" },
      };
      const r = ratingMap[rating] || { status: "unknown", label: rating };
      checks.push({
        id: "safety_rating",
        label: "Safety Rating",
        status: r.status,
        detail: `${r.label}${ratingDate ? ` (rated ${ratingDate})` : ""}. `
          + (rating === "U" ? "An Unsatisfactory rating may lead to an operations out-of-service order." : "")
          + (rating === "C" ? "A Conditional rating indicates deficiencies that need correction." : ""),
      });
    }

    // ── Check 5: Operating Authority ──
    if (carrier) {
      const commonActive = carrier.commonAuthorityStatus === "A";
      const contractActive = carrier.contractAuthorityStatus === "A";
      const brokerActive = carrier.brokerAuthorityStatus === "A";
      const isForHire = census?.authorized_for_hire || false;

      if (isForHire && !commonActive && !contractActive) {
        checks.push({
          id: "authority",
          label: "Operating Authority",
          status: "red",
          detail: "For-hire carrier without active operating authority. Common authority: "
            + (carrier.commonAuthorityStatus || "None") + ", Contract authority: "
            + (carrier.contractAuthorityStatus || "None")
            + ". You cannot legally transport freight for compensation without active authority.",
        });
      } else if (commonActive || contractActive || brokerActive) {
        const types: string[] = [];
        if (commonActive) types.push("Common");
        if (contractActive) types.push("Contract");
        if (brokerActive) types.push("Broker");
        checks.push({
          id: "authority",
          label: "Operating Authority",
          status: "green",
          detail: `Active authority: ${types.join(", ")}.`,
        });
      }
    }

    // ── Check 6: Out-of-Service Rates ──
    if (carrier) {
      const driverOos = parseFloat(carrier.driverOosRate) || 0;
      const driverNat = parseFloat(carrier.driverOosRateNationalAverage) || 5.51;
      const vehicleOos = parseFloat(carrier.vehicleOosRate) || 0;
      const vehicleNat = parseFloat(carrier.vehicleOosRateNationalAverage) || 20.72;

      if (driverOos > driverNat * 1.5 || vehicleOos > vehicleNat * 1.5) {
        checks.push({
          id: "oos_rate",
          label: "Out-of-Service Rate",
          status: "red",
          detail: `Driver OOS: ${driverOos.toFixed(1)}% (national avg: ${driverNat}%). `
            + `Vehicle OOS: ${vehicleOos.toFixed(1)}% (national avg: ${vehicleNat}%). `
            + `Significantly above national average — targeted for increased inspections.`,
        });
      } else if (driverOos > driverNat || vehicleOos > vehicleNat) {
        checks.push({
          id: "oos_rate",
          label: "Out-of-Service Rate",
          status: "yellow",
          detail: `Driver OOS: ${driverOos.toFixed(1)}% (national avg: ${driverNat}%). `
            + `Vehicle OOS: ${vehicleOos.toFixed(1)}% (national avg: ${vehicleNat}%). `
            + `Above national average.`,
        });
      } else if (carrier.vehicleInsp > 0 || carrier.driverInsp > 0) {
        checks.push({
          id: "oos_rate",
          label: "Out-of-Service Rate",
          status: "green",
          detail: `Driver OOS: ${driverOos.toFixed(1)}% (national avg: ${driverNat}%). `
            + `Vehicle OOS: ${vehicleOos.toFixed(1)}% (national avg: ${vehicleNat}%). Within normal range.`,
        });
      }
    }

    // ── Check 7: Crash History ──
    if (carrier) {
      const crashes = carrier.crashTotal || 0;
      const fatal = carrier.fatalCrash || 0;
      const injury = carrier.injCrash || 0;
      if (fatal > 0) {
        checks.push({
          id: "crashes",
          label: "Crash Record",
          status: "red",
          detail: `${crashes} total crashes on record, including ${fatal} fatal and ${injury} injury crashes.`,
        });
      } else if (crashes > 0) {
        checks.push({
          id: "crashes",
          label: "Crash Record",
          status: "yellow",
          detail: `${crashes} crash(es) on record, ${injury} with injuries. No fatalities.`,
        });
      } else {
        checks.push({
          id: "crashes",
          label: "Crash Record",
          status: "green",
          detail: "No crashes on record.",
        });
      }
    }

    // Build response
    const redCount = checks.filter(c => c.status === "red").length;
    const yellowCount = checks.filter(c => c.status === "yellow").length;

    res.json({
      dot_number: rawDot,
      legal_name: name,
      dba_name: dba || null,
      phy_city: carrier?.phyCity || census?.phy_city || null,
      phy_state: carrier?.phyState || census?.phy_state || null,
      telephone: census?.telephone || null,
      email: census?.email_address || null,
      fleet: {
        power_units: carrier?.totalPowerUnits ?? census?.nbr_power_unit ?? null,
        drivers: carrier?.totalDrivers ?? census?.driver_total ?? null,
      },
      mcs150_date: census?.mcs150_parsed || null,
      carrier_type: carrier?.censusTypeId?.censusTypeDesc || census?.carrier_operation || null,
      for_hire: census?.authorized_for_hire || false,
      checks,
      summary: {
        red: redCount,
        yellow: yellowCount,
        green: checks.filter(c => c.status === "green").length,
        total: checks.length,
      },
      checked_at: new Date().toISOString(),
    });
  } catch (err) {
    console.error("[dot-lookup] Error:", err);
    res.status(500).json({ error: "DOT lookup failed." });
  }
});

// ── Name Search ─────────────────────────────────────────────────────

router.get("/api/v1/dot/search", async (req, res) => {
  const name = (req.query.name as string || "").trim();
  if (!name || name.length < 2) {
    res.status(400).json({ error: "Provide a business name (at least 2 characters)." });
    return;
  }

  try {
    const result = await pool.query(
      `SELECT dot_number, legal_name, dba_name, phy_city, phy_state,
              nbr_power_unit, authorized_for_hire, mcs150_parsed
       FROM fmcsa_carriers
       WHERE legal_name ILIKE $1 OR dba_name ILIKE $1
       ORDER BY legal_name
       LIMIT 50`,
      [`%${name}%`],
    );

    res.json({
      results: result.rows,
      count: result.rows.length,
      query: name,
      source: "FMCSA Motor Carrier Census",
    });
  } catch (err) {
    console.error("[dot-search] Error:", err);
    res.status(500).json({ error: "Search failed." });
  }
});

export default router;