/**
 * Crawler LLM — Transceiver spec physical plausibility validator.
 *
 * Runs AFTER LLM extraction to catch technically impossible combinations
 * (e.g. 100G over SFP, 850nm on SMF, 80km over MMF). Complements
 * validator.ts which checks stock/price sanity.
 *
 * Returns a SpecValidationResult with:
 *   - passed: false blocks DB write and lowers training data confidence tier
 *   - warnings: still writes to DB but flags for human review
 *   - confidence_delta: adjustment applied to the LLM confidence score
 */

// ─────────────────────────────────────────────────────────────────────────────
// Type definitions
// ─────────────────────────────────────────────────────────────────────────────

export interface ExtractedSpec {
  part_number?: string | null;
  form_factor?: string | null;
  speed_gbps?: number | null;
  reach_meters?: number | null;
  fiber_type?: string | null;    // "SMF" | "MMF" | "CU" | "DAC" | "AOC"
  connector?: string | null;
  wavelengths?: string | null;   // e.g. "850nm" or "1310nm TX / 1490nm RX"
  ieee_standard?: string | null; // e.g. "100GBASE-SR4"
  dom_support?: boolean | null;
}

export interface SpecValidationResult {
  passed: boolean;
  errors: string[];
  warnings: string[];
  confidence_delta: number;   // negative = reduce LLM confidence score
  tier: "high" | "medium" | "low" | "rejected";
}

// ─────────────────────────────────────────────────────────────────────────────
// Compatibility tables
// ─────────────────────────────────────────────────────────────────────────────

/** Max rated speed per form factor (Gbps).  DAC/AOC = same form factor shell. */
const FORM_FACTOR_MAX_SPEED: Record<string, number> = {
  "GBIC":     1,
  "SFP":      4.25,   // 4G FC max; 1G Ethernet common
  "SFP+":     28.05,  // nominally 10G but 16G FC / 25G variants exist
  "SFP28":    28.05,
  "SFP56":    56,
  "SFP-DD":   100,    // dual-lane SFP
  "QSFP":     40,
  "QSFP+":    40,
  "QSFP28":   112,    // 4×25G = 100G; some push 112G
  "QSFP56":   224,    // 4×56G = 200G
  "QSFP-DD":  800,    // 8×100G
  "QSFP112":  800,
  "OSFP":     800,
  "OSFP-RHS": 800,
  "CFP":      100,
  "CFP2":     400,
  "CFP4":     100,
  "CFP8":     400,
  "XFP":      10,
  "X2":       10,
  "XENPAK":   10,
  "DSFP":     100,
  "CSFP":     2.5,
};

/** Min rated speed per form factor (Gbps). Catches wild mismatches. */
const FORM_FACTOR_MIN_SPEED: Record<string, number> = {
  "GBIC":    0.1,
  "SFP":     0.1,
  "SFP+":    1,
  "SFP28":   10,
  "SFP56":   25,
  "SFP-DD":  50,
  "QSFP":    4,
  "QSFP+":   10,
  "QSFP28":  40,
  "QSFP56":  100,
  "QSFP-DD": 100,
  "QSFP112": 200,
  "OSFP":    200,
  "OSFP-RHS":200,
  "CFP":     10,
  "CFP2":    40,
  "CFP4":    10,
  "CFP8":    100,
  "XFP":     10,
  "X2":      10,
  "XENPAK":  10,
  "DSFP":    25,
  "CSFP":    0.1,
};

/**
 * Wavelength → expected fiber type.
 * 850 nm is classically MMF; 1270–1610 nm is SMF.
 * Exceptions: some 1310nm SFP (1000BASE-LX) work on MMF with mode-conditioning.
 */
function expectedFiberForWavelength(nm: number): "MMF" | "SMF" | "either" {
  if (nm <= 900) return "MMF";
  if (nm >= 1260) return "SMF";
  return "either";
}

/** Max practical reach per fiber type (meters). Soft sanity limit. */
const MAX_REACH: Record<string, number> = {
  MMF: 4000,    // OM5 push ~3.5km; 4km is outer limit for 100M FX
  SMF: 200_000, // 200km coherent ZR is real
  CU:  100,
  DAC: 30,
  AOC: 200,
};

/** Known IEEE standards and their canonical speed (Gbps) + form factor hints */
const IEEE_STANDARDS: Record<string, { speedGbps: number; fiberType?: string; reachKm?: number }> = {
  "100BASE-FX":    { speedGbps: 0.1,  fiberType: "MMF",  reachKm: 2 },
  "100BASE-LX10":  { speedGbps: 0.1,  fiberType: "SMF",  reachKm: 10 },
  "1000BASE-SX":   { speedGbps: 1,    fiberType: "MMF",  reachKm: 0.55 },
  "1000BASE-LX":   { speedGbps: 1,    fiberType: "SMF",  reachKm: 10 },
  "1000BASE-EX":   { speedGbps: 1,    fiberType: "SMF",  reachKm: 40 },
  "1000BASE-ZX":   { speedGbps: 1,    fiberType: "SMF",  reachKm: 80 },
  "1000BASE-T":    { speedGbps: 1,    fiberType: "CU" },
  "10GBASE-SR":    { speedGbps: 10,   fiberType: "MMF",  reachKm: 0.3 },
  "10GBASE-LR":    { speedGbps: 10,   fiberType: "SMF",  reachKm: 10 },
  "10GBASE-ER":    { speedGbps: 10,   fiberType: "SMF",  reachKm: 40 },
  "10GBASE-ZR":    { speedGbps: 10,   fiberType: "SMF",  reachKm: 80 },
  "25GBASE-SR":    { speedGbps: 25,   fiberType: "MMF",  reachKm: 0.1 },
  "25GBASE-LR":    { speedGbps: 25,   fiberType: "SMF",  reachKm: 10 },
  "25GBASE-ER":    { speedGbps: 25,   fiberType: "SMF",  reachKm: 40 },
  "40GBASE-SR4":   { speedGbps: 40,   fiberType: "MMF",  reachKm: 0.15 },
  "40GBASE-LR4":   { speedGbps: 40,   fiberType: "SMF",  reachKm: 10 },
  "40GBASE-ER4":   { speedGbps: 40,   fiberType: "SMF",  reachKm: 40 },
  "100GBASE-SR4":  { speedGbps: 100,  fiberType: "MMF",  reachKm: 0.1 },
  "100GBASE-SR10": { speedGbps: 100,  fiberType: "MMF",  reachKm: 0.15 },
  "100GBASE-LR4":  { speedGbps: 100,  fiberType: "SMF",  reachKm: 10 },
  "100GBASE-ER4":  { speedGbps: 100,  fiberType: "SMF",  reachKm: 40 },
  "100GBASE-ZR":   { speedGbps: 100,  fiberType: "SMF",  reachKm: 80 },
  "400GBASE-SR4":  { speedGbps: 400,  fiberType: "MMF",  reachKm: 0.1 },
  "400GBASE-SR8":  { speedGbps: 400,  fiberType: "MMF",  reachKm: 0.1 },
  "400GBASE-LR4":  { speedGbps: 400,  fiberType: "SMF",  reachKm: 10 },
  "400GBASE-LR8":  { speedGbps: 400,  fiberType: "SMF",  reachKm: 10 },
  "400GBASE-ER8":  { speedGbps: 400,  fiberType: "SMF",  reachKm: 40 },
  "400GBASE-ZR":   { speedGbps: 400,  fiberType: "SMF",  reachKm: 80 },
  "400ZR":         { speedGbps: 400,  fiberType: "SMF",  reachKm: 120 },
  "800GBASE-SR8":  { speedGbps: 800,  fiberType: "MMF",  reachKm: 0.1 },
  "800GBASE-LR4":  { speedGbps: 800,  fiberType: "SMF",  reachKm: 2 },
};

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

/** Parse first numeric wavelength from a string like "850nm" or "1310nm TX / 1490nm RX" */
function parsePrimaryWavelength(wl: string): number | null {
  const match = wl.match(/(\d{3,4})\s*nm/);
  return match ? parseInt(match[1], 10) : null;
}

function normalizeFormFactor(ff: string): string {
  return ff.trim().toUpperCase().replace(/\s+/g, "");
}

function normalizeStandard(s: string): string {
  return s.trim().toUpperCase().replace(/\s+/g, "").replace("BASE-", "BASE-");
}

// ─────────────────────────────────────────────────────────────────────────────
// Main validator
// ─────────────────────────────────────────────────────────────────────────────

export function validateTransceiverSpec(spec: ExtractedSpec): SpecValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];
  let confidenceDelta = 0;

  const ff = spec.form_factor ? normalizeFormFactor(spec.form_factor) : null;
  const speedGbps = spec.speed_gbps ?? null;
  const fiberType = spec.fiber_type?.toUpperCase().trim() ?? null;
  const reachM = spec.reach_meters ?? null;
  const wavelengths = spec.wavelengths ?? null;

  // ── 1. Form factor ↔ speed compatibility ──────────────────────────────────
  if (ff && speedGbps !== null) {
    const maxSpeed = FORM_FACTOR_MAX_SPEED[ff];
    const minSpeed = FORM_FACTOR_MIN_SPEED[ff];

    if (maxSpeed !== undefined && speedGbps > maxSpeed * 1.15) {
      errors.push(
        `Speed ${speedGbps}G exceeds ${ff} maximum (${maxSpeed}G). Physically impossible.`
      );
      confidenceDelta -= 0.4;
    }

    if (minSpeed !== undefined && speedGbps < minSpeed * 0.5) {
      warnings.push(
        `Speed ${speedGbps}G is unusually low for ${ff} (typical min ${minSpeed}G). Verify.`
      );
      confidenceDelta -= 0.1;
    }
  }

  // ── 2. Wavelength ↔ fiber type consistency ────────────────────────────────
  if (wavelengths && fiberType && fiberType !== "DAC" && fiberType !== "AOC" && fiberType !== "CU") {
    const primaryNm = parsePrimaryWavelength(wavelengths);
    if (primaryNm !== null) {
      const expectedFiber = expectedFiberForWavelength(primaryNm);

      if (expectedFiber === "MMF" && fiberType === "SMF") {
        errors.push(
          `${primaryNm}nm is a multi-mode wavelength but fiber_type is SMF. Check the source.`
        );
        confidenceDelta -= 0.3;
      }

      if (expectedFiber === "SMF" && fiberType === "MMF") {
        // 1310nm LX on MMF with mode-conditioning cable is a real thing — warn, not error
        if (primaryNm >= 1260 && primaryNm <= 1360) {
          warnings.push(
            `${primaryNm}nm on MMF is unusual. Possible mode-conditioning cable — verify.`
          );
          confidenceDelta -= 0.05;
        } else {
          errors.push(
            `${primaryNm}nm (SMF wavelength) cannot work on MMF fiber at this reach.`
          );
          confidenceDelta -= 0.35;
        }
      }
    }
  }

  // ── 3. Reach ↔ fiber type sanity ─────────────────────────────────────────
  if (reachM !== null && fiberType && fiberType in MAX_REACH) {
    const maxReach = MAX_REACH[fiberType];
    if (reachM > maxReach) {
      errors.push(
        `Reach ${reachM}m exceeds physical maximum for ${fiberType} (${maxReach}m). Data error.`
      );
      confidenceDelta -= 0.4;
    }
  }

  if (reachM !== null && fiberType === "MMF" && reachM > 2000) {
    warnings.push(
      `MMF reach ${reachM}m is very high (rare). OM5 max ~3.5km, earlier OM4 max 400m at 10G+.`
    );
    confidenceDelta -= 0.1;
  }

  // ── 4. IEEE standard cross-check ─────────────────────────────────────────
  if (spec.ieee_standard) {
    const stdKey = Object.keys(IEEE_STANDARDS).find(
      (k) => normalizeStandard(k) === normalizeStandard(spec.ieee_standard!)
    );

    if (stdKey) {
      const stdDef = IEEE_STANDARDS[stdKey];

      // Speed mismatch
      if (speedGbps !== null && Math.abs(speedGbps - stdDef.speedGbps) / stdDef.speedGbps > 0.15) {
        errors.push(
          `${spec.ieee_standard} requires ${stdDef.speedGbps}G but extracted speed is ${speedGbps}G.`
        );
        confidenceDelta -= 0.35;
      }

      // Fiber type mismatch (soft — standard may have variants)
      if (fiberType && stdDef.fiberType && fiberType !== stdDef.fiberType) {
        warnings.push(
          `${spec.ieee_standard} expects ${stdDef.fiberType} but fiber_type is ${fiberType}.`
        );
        confidenceDelta -= 0.1;
      }

      // Reach mismatch: more than 3× the defined reach is suspicious
      if (reachM !== null && stdDef.reachKm !== undefined) {
        const stdReachM = stdDef.reachKm * 1000;
        if (reachM > stdReachM * 3) {
          warnings.push(
            `Reach ${reachM}m is >3× the ${spec.ieee_standard} defined reach (${stdReachM}m). Verify — may be a proprietary extended reach variant.`
          );
          confidenceDelta -= 0.05;
        }
      }
    } else {
      // Standard not in table — not an error, just warn for unknown standards
      warnings.push(`IEEE standard "${spec.ieee_standard}" not in reference table. Accepted as-is.`);
    }
  }

  // ── 5. DAC/AOC special rules ──────────────────────────────────────────────
  if (fiberType === "DAC" || fiberType === "AOC") {
    if (reachM !== null && reachM > 30 && fiberType === "DAC") {
      warnings.push(`DAC cables > 30m are unusual (passive DAC max ~7m). Verify if active DAC or AOC.`);
      confidenceDelta -= 0.1;
    }
    if (wavelengths) {
      warnings.push(`DAC/AOC have no wavelength. Extracted wavelength "${wavelengths}" may be wrong.`);
      confidenceDelta -= 0.05;
    }
  }

  // ── 6. Connector ↔ form factor ────────────────────────────────────────────
  if (spec.connector && ff) {
    const connector = spec.connector.toUpperCase();
    const mpoBased = ["QSFP", "QSFP+", "QSFP28", "QSFP56", "QSFP-DD", "OSFP", "CFP8"];
    const scBased  = ["GBIC", "CSFP"];

    if (mpoBased.includes(ff) && connector === "SC") {
      warnings.push(`${ff} modules rarely use SC connectors. LC or MPO expected. Verify.`);
      confidenceDelta -= 0.1;
    }
    if (scBased.includes(ff) && connector === "LC") {
      // GBIC can use LC — soft warning only
      warnings.push(`${ff} with LC connector is unusual. SC more common for this form factor.`);
      confidenceDelta -= 0.05;
    }
  }

  // ── Tier assignment ───────────────────────────────────────────────────────
  const passed = errors.length === 0;
  let tier: SpecValidationResult["tier"];

  if (!passed) {
    tier = "rejected";
  } else if (warnings.length === 0 && confidenceDelta >= 0) {
    tier = "high";
  } else if (warnings.length <= 2 && confidenceDelta >= -0.15) {
    tier = "medium";
  } else {
    tier = "low";
  }

  return {
    passed,
    errors,
    warnings,
    confidence_delta: Math.max(confidenceDelta, -0.9),
    tier,
  };
}

// ─────────────────────────────────────────────────────────────────────────────
// Convenience: combine with stock validation result
// ─────────────────────────────────────────────────────────────────────────────

export interface CombinedValidationResult {
  passed: boolean;
  spec_errors: string[];
  spec_warnings: string[];
  tier: SpecValidationResult["tier"];
  adjusted_confidence: number;
}

export function combineValidations(
  specResult: SpecValidationResult,
  baseLlmConfidence: number
): CombinedValidationResult {
  const adjusted = Math.min(
    1.0,
    Math.max(0.0, baseLlmConfidence + specResult.confidence_delta)
  );

  return {
    passed: specResult.passed,
    spec_errors: specResult.errors,
    spec_warnings: specResult.warnings,
    tier: specResult.tier,
    adjusted_confidence: adjusted,
  };
}