import "server-only";
import { rawDb } from "./client";
import { isValidSort, type SortKey } from "../sort";

export interface AppSettings {
  fadeTransitions: boolean;
  fadeDurationMs: number;
  /** When emptying the recycle bin (or hard-deleting), also remove the file from disk. */
  purgeFilesOnDelete: boolean;
  /** When true, delete sends to the recycle bin instead of removing immediately. */
  useRecycleBin: boolean;
  /** Auto-purge trashed items after this many days. 0 = never auto-purge. */
  trashRetentionDays: number;
  /** Auto-purge files in library/.superseded/ after this many days. 0 = never. */
  supersededRetentionDays: number;
  defaultSort: SortKey;
  /** Hex color overriding --color-cyan / --color-cyan-glow. Empty string = use default. */
  accentPrimary: string;
  /** Hex color overriding --color-violet / --color-violet-glow. Empty string = use default. */
  accentSecondary: string;
  /** Number of cover columns in the masonry grid (2–4). */
  gridColumns: number;
  /** Number of cover columns in the portrait/front-only view (4–10). */
  gridColumnsPortrait: number;
  /** Cover grid page size — items fetched per page on `/` and per
   *  infinite-scroll append. */
  coverPageSize: number;
  /** Which layout the Settings drawer renders. "sidebar" = vertical nav
   *  with focused single-section content. "three-column" = everything
   *  visible in a 3-column wide layout. */
  settingsLayout: "sidebar" | "three-column";
  /** Absolute path to the main video library folder. Walked recursively,
   *  expected to follow the same letter-bucket structure as library/
   *  (e.g. D:\JAV\A-E\A\AOZ-200Z.mp4). Empty string disables. */
  videoLibraryPath: string;
  /** Additional video folders. These are also walked recursively, but
   *  the user typically points them at flat folders that hold files
   *  directly (e.g. E:\JAV\IBW-203.mp4). One absolute path per entry. */
  videoExtraPaths: string[];
  /** Folders scanned recursively for subtitle sidecars whose filename
   *  matches the playing video's stem or code. Empty by default — the
   *  player still finds same-folder sidecars without this. */
  subtitleExtraPaths: string[];
  /** Soft cap on data/subtitle-cache/ size in MB. When the cache grows
   *  beyond this, an LRU sweep deletes oldest-mtime entries until the
   *  total drops below 80% of the cap. 0 = unlimited. */
  subtitleCacheLimitMb: number;
  /** Playback path selector — controls how video files are streamed.
   *  - "off": always serve the original file directly via HTTP Range.
   *  - "always": always transcode through ffmpeg+NVENC HLS pipeline.
   *  - "auto-predicate": transcode only if a quick ffprobe says the file
   *    is H.264 with B-frames (the trigger profile for Chromium's sink
   *    reorder bug). Other codecs / no-B-frame H.264 → direct.
   *  - "auto-runtime": play direct first, measure dropped frames over
   *    a short pre-roll, decide per file, persist the decision. */
  transcodeMode: "off" | "always" | "auto-predicate" | "auto-runtime";
  /** Token-grammar suffix patterns used to classify video files into
   *  sequential parts. Patterns are matched at the end of the filename
   *  stem. `{N}` = digits (captured as part index), `{L}` = letter
   *  (A=1, B=2…), all other characters literal. Files in the same code
   *  group whose stem matches none of these patterns are treated as
   *  variants of the matched files (alternate encodes). */
  partSuffixPatterns: string[];
  /** WhisperJAV subtitle-generator integration. Empty cliPath disables
   *  the picker's Generate action. */
  whisperjav: WhisperJavSettings;
  /** How the pagination bar's Prev/Next/Jump buttons behave.
   *  - "url": always push a new URL, full page remount. Predictable.
   *  - "scroll": scroll within the loaded buffer; prefetch forward
   *    pages on demand; fall back to URL push only when the target is
   *    behind the SSR anchor. */
  paginationMode: "url" | "scroll";
}

export type PaginationMode = AppSettings["paginationMode"];

export interface WhisperJavSettings {
  /** Resolved CLI path. Empty string = feature disabled. */
  cliPath: string;
  quality: "fast" | "balanced" | "qwen";
  sourceLanguage: "japanese" | "korean" | "chinese" | "english";
  outputMode: "native" | "direct-to-english";
  sensitivity: "conservative" | "balanced" | "aggressive";
  outputLocation: "beside-video" | "data-folder";
  /** When true, append --no-signature so generated subs don't include
   *  WhisperJAV's trailing technical signature cue. */
  noSignature: boolean;
  /** Days to keep failed / cancelled job temp directories. Successful
   *  job dirs are deleted immediately. 0 = keep forever. */
  retentionDays: number;
}

export type TranscodeMode = AppSettings["transcodeMode"];

export const APP_SETTINGS_DEFAULTS: AppSettings = {
  fadeTransitions: true,
  fadeDurationMs: 400,
  purgeFilesOnDelete: true,
  useRecycleBin: true,
  trashRetentionDays: 30,
  supersededRetentionDays: 30,
  defaultSort: "newest",
  accentPrimary: "",
  accentSecondary: "",
  gridColumns: 3,
  gridColumnsPortrait: 6,
  coverPageSize: 100,
  settingsLayout: "sidebar",
  videoLibraryPath: "",
  videoExtraPaths: [],
  subtitleExtraPaths: [],
  subtitleCacheLimitMb: 100,
  transcodeMode: "off",
  partSuffixPatterns: ["-cd{N}", ".part{N}", "_{N}", "_{L}"],
  whisperjav: {
    cliPath: "",
    quality: "balanced",
    sourceLanguage: "japanese",
    outputMode: "native",
    sensitivity: "balanced",
    outputLocation: "beside-video",
    noSignature: true,
    retentionDays: 30,
  },
  paginationMode: "scroll",
};

const HEX_RE = /^#([0-9a-fA-F]{6})$/;
function decodeHex(raw: string): string | undefined {
  if (raw === "") return "";
  return HEX_RE.test(raw) ? raw.toLowerCase() : undefined;
}

// Pin cache to globalThis so multiple bundle copies of this module
// (Turbopack dev can produce more than one) share state — otherwise
// the server action that saves a setting writes to one cache while
// the queue worker keeps reading a stale value from another.
declare global {
  // eslint-disable-next-line no-var
  var __pinkudexAppSettingsCache: Map<string, string | undefined> | undefined;
}
const cache: Map<string, string | undefined> =
  global.__pinkudexAppSettingsCache ?? (global.__pinkudexAppSettingsCache = new Map());

function getRaw(key: string): string | undefined {
  if (cache.has(key)) return cache.get(key);
  const row = rawDb.prepare(`SELECT value FROM app_settings WHERE key = ?`).get(key) as
    | { value: string }
    | undefined;
  cache.set(key, row?.value);
  return row?.value;
}

function setRaw(key: string, value: string): void {
  rawDb.prepare(`
    INSERT INTO app_settings (key, value) VALUES (?, ?)
    ON CONFLICT(key) DO UPDATE SET value = excluded.value
  `).run(key, value);
  cache.set(key, value);
}

const SERIALIZERS: { [K in keyof AppSettings]: { encode: (v: AppSettings[K]) => string; decode: (raw: string) => AppSettings[K] | undefined } } = {
  fadeTransitions:      { encode: (v) => (v ? "1" : "0"), decode: (r) => r === "1" ? true : r === "0" ? false : undefined },
  fadeDurationMs:       { encode: (v) => String(v), decode: (r) => { const n = Number(r); return Number.isFinite(n) ? n : undefined; } },
  purgeFilesOnDelete:   { encode: (v) => (v ? "1" : "0"), decode: (r) => r === "1" ? true : r === "0" ? false : undefined },
  useRecycleBin:        { encode: (v) => (v ? "1" : "0"), decode: (r) => r === "1" ? true : r === "0" ? false : undefined },
  trashRetentionDays:   { encode: (v) => String(v), decode: (r) => { const n = Number(r); return Number.isFinite(n) && n >= 0 ? n : undefined; } },
  supersededRetentionDays: { encode: (v) => String(v), decode: (r) => { const n = Number(r); return Number.isFinite(n) && n >= 0 ? n : undefined; } },
  defaultSort:          { encode: (v) => v, decode: (r) => isValidSort(r) ? r : undefined },
  accentPrimary:        { encode: (v) => v, decode: decodeHex },
  accentSecondary:      { encode: (v) => v, decode: decodeHex },
  gridColumns:          { encode: (v) => String(v), decode: (r) => { const n = Number(r); return Number.isFinite(n) && n >= 2 && n <= 4 ? Math.round(n) : undefined; } },
  gridColumnsPortrait:  { encode: (v) => String(v), decode: (r) => { const n = Number(r); return Number.isFinite(n) && n >= 4 && n <= 10 ? Math.round(n) : undefined; } },
  coverPageSize:        { encode: (v) => String(v), decode: (r) => { const n = Number(r); return Number.isFinite(n) && n >= 25 && n <= 500 ? Math.round(n) : undefined; } },
  settingsLayout:       { encode: (v) => v, decode: (r) => r === "sidebar" || r === "three-column" ? r : undefined },
  videoLibraryPath:     { encode: (v) => v, decode: (r) => typeof r === "string" ? r : undefined },
  videoExtraPaths: {
    // Stored as newline-separated absolute paths so the value remains a
    // plain string at the storage layer. Empty / blank lines are stripped.
    encode: (v) => (v ?? []).filter((s) => s && s.trim()).join("\n"),
    decode: (r) => typeof r === "string"
      ? r.split(/\r?\n/).map((s) => s.trim()).filter(Boolean)
      : undefined,
  },
  subtitleExtraPaths: {
    encode: (v) => (v ?? []).filter((s) => s && s.trim()).join("\n"),
    decode: (r) => typeof r === "string"
      ? r.split(/\r?\n/).map((s) => s.trim()).filter(Boolean)
      : undefined,
  },
  subtitleCacheLimitMb: {
    encode: (v) => String(v),
    decode: (r) => {
      const n = Number(r);
      return Number.isFinite(n) && n >= 0 ? Math.floor(n) : undefined;
    },
  },
  transcodeMode: {
    encode: (v) => v,
    decode: (r) => {
      if (r === "off" || r === "always" || r === "auto-predicate" || r === "auto-runtime") return r;
      // Migrate legacy boolean values from the old `transcodePlayback` setting.
      if (r === "1") return "always";
      if (r === "0") return "off";
      return undefined;
    },
  },
  partSuffixPatterns: {
    // Newline-separated to keep the storage value a plain string. Empty
    // / blank lines are stripped on decode.
    encode: (v) => (v ?? []).map((s) => s ?? "").map((s) => s.trim()).filter(Boolean).join("\n"),
    decode: (r) => typeof r === "string"
      ? r.split(/\r?\n/).map((s) => s.trim()).filter(Boolean)
      : undefined,
  },
  paginationMode: {
    encode: (v) => v,
    decode: (r) => {
      if (r === "url" || r === "scroll") return r;
      // Migrate any persisted "split" rows to scroll (the default).
      if (r === "split") return "scroll";
      return undefined;
    },
  },
  whisperjav: {
    encode: (v) => JSON.stringify(v ?? APP_SETTINGS_DEFAULTS.whisperjav),
    decode: (r) => {
      if (typeof r !== "string") return undefined;
      try {
        const parsed = JSON.parse(r) as Partial<WhisperJavSettings>;
        // Merge with defaults so older rows missing a key still resolve.
        return { ...APP_SETTINGS_DEFAULTS.whisperjav, ...parsed };
      } catch {
        return undefined;
      }
    },
  },
};

export function getAppSetting<K extends keyof AppSettings>(key: K): AppSettings[K] {
  const raw = getRaw(key);
  const decoded = raw == null ? undefined : SERIALIZERS[key].decode(raw);
  return (decoded ?? APP_SETTINGS_DEFAULTS[key]) as AppSettings[K];
}

export function setAppSetting<K extends keyof AppSettings>(key: K, value: AppSettings[K]): void {
  setRaw(key, SERIALIZERS[key].encode(value));
}

export function getAllAppSettings(): AppSettings {
  return {
    fadeTransitions:      getAppSetting("fadeTransitions"),
    fadeDurationMs:       getAppSetting("fadeDurationMs"),
    purgeFilesOnDelete:   getAppSetting("purgeFilesOnDelete"),
    useRecycleBin:        getAppSetting("useRecycleBin"),
    trashRetentionDays:   getAppSetting("trashRetentionDays"),
    supersededRetentionDays: getAppSetting("supersededRetentionDays"),
    defaultSort:          getAppSetting("defaultSort"),
    accentPrimary:        getAppSetting("accentPrimary"),
    accentSecondary:      getAppSetting("accentSecondary"),
    gridColumns:          getAppSetting("gridColumns"),
    gridColumnsPortrait:  getAppSetting("gridColumnsPortrait"),
    coverPageSize:        getAppSetting("coverPageSize"),
    settingsLayout:       getAppSetting("settingsLayout"),
    videoLibraryPath:     getAppSetting("videoLibraryPath"),
    videoExtraPaths:      getAppSetting("videoExtraPaths"),
    subtitleExtraPaths:   getAppSetting("subtitleExtraPaths"),
    subtitleCacheLimitMb: getAppSetting("subtitleCacheLimitMb"),
    transcodeMode:        getAppSetting("transcodeMode"),
    partSuffixPatterns:   getAppSetting("partSuffixPatterns"),
    whisperjav:           getAppSetting("whisperjav"),
    paginationMode:       getAppSetting("paginationMode"),
  };
}

export function clearAppSettingsCache(): void {
  cache.clear();
}