import { getFilterShortName } from "@/lib/peqAudio";
import {
  BAND_FREQ_MAX,
  BAND_FREQ_MIN,
  BAND_GAIN_MAX,
  BAND_GAIN_MIN,
  BAND_Q_MAX,
  BAND_Q_MIN,
} from "./eqConstants";
import type { BandParamKind } from "./types";

export function eqInterp(template: string | undefined, vars: Record<string, string | number>): string {
  if (!template) return "";
  let s = template;
  for (const [k, v] of Object.entries(vars)) {
    s = s.split(`{{${k}}}`).join(String(v));
  }
  return s;
}

/** 将设备/表单中的频率统一为 Hz 数值；无法解析时返回 null */
export function normalizeBandFreqHz(freq: unknown): number | null {
  if (typeof freq === "number" && Number.isFinite(freq)) return freq;
  if (typeof freq === "string") {
    const trimmed = freq.trim().replace(/,/g, "");
    if (!trimmed) return null;
    let s = trimmed.toLowerCase().replace(/hz$/, "");
    const kHz = /k(hz)?$/.test(s);
    if (kHz) s = s.replace(/k(hz)?$/, "");
    const num = Number.parseFloat(s);
    return Number.isFinite(num) ? (kHz ? num * 1000 : num) : null;
  }
  return null;
}

export function formatBandGainDisplay(gain: unknown) {
  const db = typeof gain === "number" && Number.isFinite(gain) ? gain : Number(gain);
  if (!Number.isFinite(db)) return "0.0 dB";
  const text = db.toFixed(1);
  return `${db >= 0 ? `+${text}` : text} dB`;
}

export function formatBandQDisplay(q: unknown) {
  const n = typeof q === "number" && Number.isFinite(q) ? q : Number(q);
  return Number.isFinite(n) ? n.toFixed(2) : "—";
}

export function formatBandFreqDisplay(freq: unknown) {
  const hz = normalizeBandFreqHz(freq);
  if (hz === null) return "—";
  if (hz >= 1000) {
    return `${(hz / 1000).toFixed(2).replace(/\.?0+$/, "")} kHz`;
  }
  return `${Math.round(hz)} Hz`;
}

export function formatBandParamForInput(
  kind: BandParamKind,
  band: { freq: number; gain: number; q: number },
) {
  switch (kind) {
    case "freq":
      return String(band.freq);
    case "gain":
      return band.gain.toFixed(1);
    case "q":
      return band.q.toFixed(2);
  }
}

export function parseBandParamInput(
  kind: BandParamKind,
  raw: string,
  messages: { invalid: string; outOfRange: string },
): { ok: true; value: number } | { ok: false; message: string } {
  const trimmed = raw.trim();
  if (!trimmed) return { ok: false, message: messages.invalid };

  if (kind === "freq") {
    let s = trimmed.replace(/\s+/g, "").toLowerCase().replace(/hz$/, "");
    const kHz = /k(hz)?$/.test(s);
    if (kHz) s = s.replace(/k(hz)?$/, "");
    const num = Number.parseFloat(s);
    if (!Number.isFinite(num)) return { ok: false, message: messages.invalid };
    const hz = Math.round(kHz ? num * 1000 : num);
    if (hz < BAND_FREQ_MIN || hz > BAND_FREQ_MAX) {
      return { ok: false, message: messages.outOfRange };
    }
    return { ok: true, value: hz };
  }

  if (kind === "gain") {
    const s = trimmed.replace(/\s*dB\s*$/i, "").trim();
    const num = Number.parseFloat(s);
    if (!Number.isFinite(num)) return { ok: false, message: messages.invalid };
    const gain = Number(num.toFixed(1));
    if (gain < BAND_GAIN_MIN || gain > BAND_GAIN_MAX) {
      return { ok: false, message: messages.outOfRange };
    }
    return { ok: true, value: gain };
  }

  const num = Number.parseFloat(trimmed);
  if (!Number.isFinite(num)) return { ok: false, message: messages.invalid };
  const q = Number(num.toFixed(2));
  if (q < BAND_Q_MIN || q > BAND_Q_MAX) {
    return { ok: false, message: messages.outOfRange };
  }
  return { ok: true, value: q };
}

export function normalizeFilterType(type: string | number | undefined): string {
  if (type === undefined || type === null) return "PEAK";
  if (typeof type === "number") {
    switch (type) {
      case 0:
        return "LPF";
      case 1:
        return "HPF";
      case 2:
        return "BPF";
      case 3:
        return "NOTCH";
      case 4:
        return "PEAK";
      case 5:
        return "LSHELF";
      case 6:
        return "HSHELF";
      case 7:
        return "APF";
      default:
        return "PEAK";
    }
  }
  return getFilterShortName(type);
}

/** 10 段滤波器按钮上的紧凑频率标签（始终为数字，避免被翻译插件改成英文单词） */
export function freqLabel(freq: unknown) {
  const hz = normalizeBandFreqHz(freq);
  if (hz === null) return "—";
  if (hz >= 1000) {
    const k = hz / 1000;
    const text = k >= 10 ? String(Math.round(k)) : k.toFixed(1).replace(/\.0$/, "");
    return `${text}K`;
  }
  return String(Math.round(hz));
}