// 回响星核 / Echo Nexus — 深空信标
// v0.5：每日挑战 + 本地排行榜
// v0.8：周挑战 + 信标链（连续完成奖励）
// 一个自包含的"每日挑战 + 周挑战 + 连续完成链"元系统，纯 localStorage 持久化。

/** 每日挑战类型 */
export type BeaconChallengeType =
  | "decode" // 解码 N 颗晶体
  | "expedition" // 完成 N 次探险
  | "pulse" // 发起 N 次脉冲
  | "boss" // 击破 N 处 BOSS
  | "insight"; // 累计 N 洞见

/** 挑战难度档位 */
export type BeaconDifficulty = "routine" | "anomaly" | "singular";

/** 一条排行榜记录 */
export interface BeaconScoreEntry {
  /** 提交时间戳 */
  timestamp: number;
  /** 日期 key（YYYY-MM-DD）或周 key（YYYY-Www） */
  dateKey: string;
  /** 挑战类型 */
  challenge: BeaconChallengeType;
  /** 难度 */
  difficulty: BeaconDifficulty;
  /** 完成度（0-1，1 = 完成） */
  progress: number;
  /** 最终得分 */
  score: number;
  /** 完成时长（秒），未完成则记 0 */
  durationSec: number;
  /** v0.8：是否为周挑战记录（日挑战默认 false / undefined） */
  isWeekly?: boolean;
}

/** 每日挑战定义 */
export interface BeaconDailyChallenge {
  /** 日期 key（YYYY-MM-DD，UTC） */
  dateKey: string;
  /** 挑战类型 */
  type: BeaconChallengeType;
  /** 难度 */
  difficulty: BeaconDifficulty;
  /** 目标数值 */
  goal: number;
  /** 奖励：完成时洞见 */
  rewardInsight: number;
  /** 奖励：完成时接触进度 */
  rewardContact: number;
  /** 使用的种子（可复现） */
  seed: number;
  /** 友好标题 */
  title: string;
  /** 描述 */
  desc: string;
}

/** 难度配置 */
export const BEACON_DIFFICULTY: Record<
  BeaconDifficulty,
  { label: string; color: string; glow: string; mult: number; icon: string }
> = {
  routine: {
    label: "常规信标",
    color: "#34d399",
    glow: "rgba(52,211,153,0.45)",
    mult: 1,
    icon: "◍",
  },
  anomaly: {
    label: "异常波动",
    color: "#fbbf24",
    glow: "rgba(251,191,36,0.45)",
    mult: 1.6,
    icon: "◈",
  },
  singular: {
    label: "奇点回响",
    color: "#f43f5e",
    glow: "rgba(244,63,94,0.5)",
    mult: 2.4,
    icon: "✶",
  },
};

/** 挑战类型元信息 */
export const BEACON_TYPE_META: Record<
  BeaconChallengeType,
  { label: string; icon: string; unit: string; verb: string }
> = {
  decode: { label: "解码协议", icon: "❖", unit: "颗", verb: "解码记忆晶体" },
  expedition: { label: "远征指令", icon: "⬢", unit: "次", verb: "完成遗迹探险" },
  pulse: { label: "脉冲任务", icon: "✺", unit: "次", verb: "发起脉冲扫描" },
  boss: { label: "猎杀契约", icon: "☠", unit: "处", verb: "击破维度 BOSS" },
  insight: { label: "洞见采集", icon: "✦", unit: "点", verb: "累计获取洞见" },
};

/** 取今日日期 key（UTC，保证全球同一天同一挑战） */
export function getTodayKey(now: Date = new Date()): string {
  const y = now.getUTCFullYear();
  const m = String(now.getUTCMonth() + 1).padStart(2, "0");
  const d = String(now.getUTCDate()).padStart(2, "0");
  return `${y}-${m}-${d}`;
}

/** 把日期 key 转成数值种子 */
function dateKeyToSeed(dateKey: string): number {
  let h = 2166136261 >>> 0;
  for (let i = 0; i < dateKey.length; i++) {
    h ^= dateKey.charCodeAt(i);
    h = Math.imul(h, 16777619) >>> 0;
  }
  return h >>> 0;
}

/** mulberry32 PRNG（可复现） */
function mulberry32(seed: number): () => number {
  let a = seed >>> 0;
  return () => {
    a |= 0;
    a = (a + 0x6d2b79f5) | 0;
    let t = Math.imul(a ^ (a >>> 15), 1 | a);
    t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
  };
}

/** 生成今日每日挑战（确定性：同一天同一种子 → 同一挑战） */
export function generateDailyChallenge(now: Date = new Date()): BeaconDailyChallenge {
  const dateKey = getTodayKey(now);
  const seed = dateKeyToSeed(dateKey);
  const rng = mulberry32(seed);

  // 选类型（5 种）
  const types: BeaconChallengeType[] = ["decode", "expedition", "pulse", "boss", "insight"];
  const type = types[Math.floor(rng() * types.length)];

  // 选难度（加权：常规 55% / 异常 33% / 奇点 12%）
  const dr = rng();
  const difficulty: BeaconDifficulty =
    dr < 0.55 ? "routine" : dr < 0.88 ? "anomaly" : "singular";

  const diffMult = BEACON_DIFFICULTY[difficulty].mult;

  // 按类型定 goal 与奖励
  let goal = 0;
  let rewardInsight = 0;
  let rewardContact = 0;
  let title = "";
  let desc = "";

  switch (type) {
    case "decode":
      goal = Math.round((6 + Math.floor(rng() * 10)) * diffMult); // 6-15 × mult
      rewardInsight = Math.round(goal * 4 * diffMult);
      rewardContact = goal * 0.8;
      title = `解码 ${goal} 颗记忆晶体`;
      desc = `深空信标要求解码 ${goal} 颗晶体。谐振风暴期间效率更高。`;
      break;
    case "expedition":
      goal = Math.max(1, Math.round((1 + Math.floor(rng() * 3)) * diffMult)); // 1-3 × mult
      rewardInsight = Math.round(goal * 12 * diffMult);
      rewardContact = goal * 1.5;
      title = `完成 ${goal} 次遗迹探险`;
      desc = `派出探险队完成 ${goal} 次远征，无论胜负均计入。`;
      break;
    case "pulse":
      goal = Math.round((20 + Math.floor(rng() * 30)) * diffMult); // 20-49 × mult
      rewardInsight = Math.round(goal * 1.2 * diffMult);
      rewardContact = goal * 0.3;
      title = `发起 ${goal} 次脉冲扫描`;
      desc = `主动点击晶体发起 ${goal} 次脉冲。连击可叠加加成。`;
      break;
    case "boss":
      goal = Math.max(1, Math.round(diffMult)); // 奇点至少 2-3
      rewardInsight = Math.round(goal * 30 * diffMult);
      rewardContact = goal * 3;
      title = `击破 ${goal} 处维度 BOSS`;
      desc = `在探险终点击破 ${goal} 处 BOSS。提升探险力后再挑战。`;
      break;
    case "insight":
      goal = Math.round((40 + Math.floor(rng() * 80)) * diffMult); // 40-119 × mult
      rewardInsight = 0; // 洞见挑战不给洞见，给接触
      rewardContact = goal * 0.1;
      title = `累计获取 ${goal} 洞见`;
      desc = `通过解码、探险、星潮等途径累计 ${goal} 洞见。`;
      break;
  }

  return {
    dateKey,
    type,
    difficulty,
    goal,
    rewardInsight,
    rewardContact,
    seed,
    title,
    desc,
  };
}

/** 计算挑战得分（用于排行榜） */
export function computeBeaconScore(
  challenge: BeaconDailyChallenge,
  progress: number,
  durationSec: number
): number {
  const completion = Math.min(1, progress / challenge.goal);
  const diffMult = BEACON_DIFFICULTY[challenge.difficulty].mult;
  // 基础分 = 完成度 × 难度 × 1000；完成时长越短加分越多（上限 +500）
  const base = completion * 1000 * diffMult;
  const speedBonus =
    completion >= 1 && durationSec > 0 ? Math.max(0, 500 - durationSec * 0.5) : 0;
  return Math.round(base + speedBonus);
}

/** 排行榜 localStorage key */
export const BEACON_LEADERBOARD_KEY = "echo-nexus-beacon-lb-v1";
/** 每日进度 localStorage key（记录今日进度 + 是否领奖） */
export const BEACON_PROGRESS_KEY = "echo-nexus-beacon-prog-v1";

/** 排行榜上限 */
export const BEACON_LB_MAX = 20;

/** 今日进度记录 */
export interface BeaconDailyProgress {
  dateKey: string;
  progress: number;
  startedAt: number;
  completedAt: number | null;
  claimed: boolean;
  durationSec: number;
}

/** 读取本地排行榜（按分数降序） */
export function loadLeaderboard(): BeaconScoreEntry[] {
  if (typeof localStorage === "undefined") return [];
  try {
    const raw = localStorage.getItem(BEACON_LEADERBOARD_KEY);
    if (!raw) return [];
    const arr = JSON.parse(raw) as BeaconScoreEntry[];
    return arr.sort((a, b) => b.score - a.score).slice(0, BEACON_LB_MAX);
  } catch {
    return [];
  }
}

/** 写入一条排行榜记录 */
export function pushLeaderboardEntry(entry: BeaconScoreEntry): BeaconScoreEntry[] {
  const lb = loadLeaderboard();
  lb.push(entry);
  lb.sort((a, b) => b.score - a.score);
  const trimmed = lb.slice(0, BEACON_LB_MAX);
  if (typeof localStorage !== "undefined") {
    localStorage.setItem(BEACON_LEADERBOARD_KEY, JSON.stringify(trimmed));
  }
  return trimmed;
}

/** 读取今日进度（若 dateKey 不匹配则重置） */
export function loadDailyProgress(now: Date = new Date()): BeaconDailyProgress {
  const todayKey = getTodayKey(now);
  if (typeof localStorage === "undefined") {
    return { dateKey: todayKey, progress: 0, startedAt: Date.now(), completedAt: null, claimed: false, durationSec: 0 };
  }
  try {
    const raw = localStorage.getItem(BEACON_PROGRESS_KEY);
    if (!raw) {
      return { dateKey: todayKey, progress: 0, startedAt: Date.now(), completedAt: null, claimed: false, durationSec: 0 };
    }
    const prog = JSON.parse(raw) as BeaconDailyProgress;
    if (prog.dateKey !== todayKey) {
      // 新的一天，重置
      return { dateKey: todayKey, progress: 0, startedAt: Date.now(), completedAt: null, claimed: false, durationSec: 0 };
    }
    return prog;
  } catch {
    return { dateKey: todayKey, progress: 0, startedAt: Date.now(), completedAt: null, claimed: false, durationSec: 0 };
  }
}

/** 保存今日进度 */
export function saveDailyProgress(prog: BeaconDailyProgress): void {
  if (typeof localStorage === "undefined") return;
  localStorage.setItem(BEACON_PROGRESS_KEY, JSON.stringify(prog));
}

/** 增量更新进度，返回新进度 + 是否刚完成 */
export function addBeaconProgress(
  current: BeaconDailyProgress,
  challenge: BeaconDailyChallenge,
  delta: number
): { progress: BeaconDailyProgress; justCompleted: boolean } {
  const newProgressVal = Math.min(challenge.goal, current.progress + delta);
  const justCompleted = current.completedAt === null && newProgressVal >= challenge.goal;
  const completedAt = justCompleted ? Date.now() : current.completedAt;
  const durationSec =
    completedAt !== null ? Math.floor((completedAt - current.startedAt) / 1000) : current.durationSec;
  const next: BeaconDailyProgress = {
    ...current,
    progress: newProgressVal,
    completedAt,
    durationSec,
  };
  saveDailyProgress(next);
  return { progress: next, justCompleted };
}

/** 领取奖励：返回奖励数值 + 推送排行榜 */
export function claimBeaconReward(
  challenge: BeaconDailyChallenge,
  progress: BeaconDailyProgress
): { rewardInsight: number; rewardContact: number; score: number; leaderboard: BeaconScoreEntry[] } {
  if (progress.claimed || progress.completedAt === null) {
    return { rewardInsight: 0, rewardContact: 0, score: 0, leaderboard: loadLeaderboard() };
  }
  const score = computeBeaconScore(challenge, progress.progress, progress.durationSec);
  const entry: BeaconScoreEntry = {
    timestamp: Date.now(),
    dateKey: challenge.dateKey,
    challenge: challenge.type,
    difficulty: challenge.difficulty,
    progress: progress.progress / challenge.goal,
    score,
    durationSec: progress.durationSec,
  };
  const leaderboard = pushLeaderboardEntry(entry);
  const updated: BeaconDailyProgress = { ...progress, claimed: true };
  saveDailyProgress(updated);
  return {
    rewardInsight: challenge.rewardInsight,
    rewardContact: challenge.rewardContact,
    score,
    leaderboard,
  };
}

/** 距离 UTC 次日 0 点的毫秒数（用于倒计时） */
export function msUntilNextDay(now: Date = new Date()): number {
  const next = Date.UTC(
    now.getUTCFullYear(),
    now.getUTCMonth(),
    now.getUTCDate() + 1,
    0,
    0,
    0
  );
  return Math.max(0, next - now.getTime());
}

/** 格式化倒计时为 HH:MM:SS */
export function formatCountdown(ms: number): string {
  const total = Math.max(0, Math.floor(ms / 1000));
  const h = String(Math.floor(total / 3600)).padStart(2, "0");
  const m = String(Math.floor((total % 3600) / 60)).padStart(2, "0");
  const s = String(total % 60).padStart(2, "0");
  return `${h}:${m}:${s}`;
}

// ===========================================================================
// 周挑战（WEEKLY CHALLENGE）— v0.8
// 每周一 UTC 0 点刷新一个"周挑战"，目标更大、奖励更好，与日挑战并行存在。
// 同一周同一种子 → 同一挑战（确定性）。难度强制 anomaly/singular（加权 60/40）。
// ===========================================================================

/** 周挑战 localStorage key */
export const BEACON_WEEKLY_KEY = "echo-nexus-beacon-weekly-v1";

/** 周挑战定义 */
export interface BeaconWeeklyChallenge {
  /** ISO 周键（YYYY-Www，如 "2026-W26"） */
  weekKey: string;
  /** 挑战类型 */
  type: BeaconChallengeType;
  /** 难度（固定 anomaly 或 singular） */
  difficulty: "anomaly" | "singular";
  /** 目标数值（日挑战的 3-5 倍） */
  goal: number;
  /** 奖励：完成时洞见 */
  rewardInsight: number;
  /** 奖励：完成时接触进度 */
  rewardContact: number;
  /** 使用的种子（可复现） */
  seed: number;
  /** 友好标题 */
  title: string;
  /** 描述 */
  desc: string;
}

/** 周挑战进度 */
export interface BeaconWeeklyProgress {
  weekKey: string;
  progress: number;
  startedAt: number;
  completedAt: number | null;
  claimed: boolean;
  durationSec: number;
}

/**
 * 计算 ISO 8601 周键（YYYY-Www），如 "2026-W26"。
 * 规则：周一为一周开始；第一周是该年至少含 4 天的第一周（即包含第一个周四）。
 */
export function getWeekKey(now: Date = new Date()): string {
  // 取 UTC 日期，避免时区偏移
  const tmp = new Date(
    Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate())
  );
  // ISO 周以周一为起点：(getUTCDay + 6) % 7 → 0=Mon, 6=Sun
  const dayNum = (tmp.getUTCDay() + 6) % 7;
  // 把日期调整到本周四（ISO 周归属年份由该周四所在的年份决定）
  tmp.setUTCDate(tmp.getUTCDate() - dayNum + 3);
  const isoYear = tmp.getUTCFullYear();
  const yearStart = Date.UTC(isoYear, 0, 1);
  const weekNum = Math.ceil(((tmp.getTime() - yearStart) / 86400000 + 1) / 7);
  return `${isoYear}-W${String(weekNum).padStart(2, "0")}`;
}

/** weekKey → 数值种子（FNV-1a 哈希） */
function weekKeyToSeed(weekKey: string): number {
  let h = 2166136261 >>> 0;
  for (let i = 0; i < weekKey.length; i++) {
    h ^= weekKey.charCodeAt(i);
    h = Math.imul(h, 16777619) >>> 0;
  }
  return h >>> 0;
}

/**
 * 生成本周周挑战（确定性：同一周同一种子 → 同一挑战）。
 * 难度强制 anomaly（60%）或 singular（40%），goal 为日挑战基准 ×3-5 倍。
 */
export function generateWeeklyChallenge(
  now: Date = new Date()
): BeaconWeeklyChallenge {
  const weekKey = getWeekKey(now);
  const seed = weekKeyToSeed(weekKey);
  const rng = mulberry32(seed);

  const types: BeaconChallengeType[] = [
    "decode",
    "expedition",
    "pulse",
    "boss",
    "insight",
  ];
  const type = types[Math.floor(rng() * types.length)];

  // 难度加权：anomaly 60% / singular 40%
  const dr = rng();
  const difficulty: "anomaly" | "singular" = dr < 0.6 ? "anomaly" : "singular";
  const diffMult = BEACON_DIFFICULTY[difficulty].mult;

  // 3-5 倍
  const mult = 3 + Math.floor(rng() * 3);

  let goal = 0;
  let rewardInsight = 0;
  let rewardContact = 0;
  let title = "";
  let desc = "";

  switch (type) {
    case "decode":
      // 日基准 6-15 × mult(3-5) → 18-75
      goal = Math.max(18, Math.round((6 + Math.floor(rng() * 10)) * diffMult * mult));
      rewardInsight = Math.round(goal * 5 * diffMult);
      rewardContact = goal * 1.2;
      title = `周界解码 · ${goal} 颗晶体`;
      desc = `本周深空信标要求解码 ${goal} 颗记忆晶体，强度为日挑战的 ${mult} 倍。`;
      break;
    case "expedition":
      // 日基准 1-3 × mult(3-5) → 3-15
      goal = Math.max(3, Math.round((1 + Math.floor(rng() * 3)) * diffMult * mult));
      rewardInsight = Math.round(goal * 14 * diffMult);
      rewardContact = goal * 2;
      title = `周界远征 · ${goal} 次探险`;
      desc = `本周派出探险队完成 ${goal} 次远征，无论胜负均计入。`;
      break;
    case "pulse":
      // 日基准 20-49 × mult(3-5) → 60-245
      goal = Math.max(60, Math.round((20 + Math.floor(rng() * 30)) * diffMult * mult));
      rewardInsight = Math.round(goal * 1.5 * diffMult);
      rewardContact = goal * 0.4;
      title = `周界脉冲 · ${goal} 次扫描`;
      desc = `本周发起 ${goal} 次脉冲扫描。连击可叠加加成。`;
      break;
    case "boss":
      // 日基准 1 × mult(3-5) → 3-12（singular mult=2.4 时上限 12）
      goal = Math.max(3, Math.round(mult * diffMult));
      rewardInsight = Math.round(goal * 35 * diffMult);
      rewardContact = goal * 4;
      title = `周界猎杀 · ${goal} 处 BOSS`;
      desc = `本周在探险终点击破 ${goal} 处维度 BOSS。提升探险力后再挑战。`;
      break;
    case "insight":
      // 日基准 40-119 × mult(3-5) → 120-595
      goal = Math.max(120, Math.round((40 + Math.floor(rng() * 80)) * diffMult * mult));
      rewardInsight = 0; // 洞见挑战不给洞见，给接触
      rewardContact = goal * 0.15;
      title = `周界洞见 · ${goal} 点`;
      desc = `本周通过解码、探险、星潮等途径累计 ${goal} 洞见。`;
      break;
  }

  return {
    weekKey,
    type,
    difficulty,
    goal,
    rewardInsight,
    rewardContact,
    seed,
    title,
    desc,
  };
}

/** 读取本周进度（若 weekKey 不匹配则重置） */
export function loadWeeklyProgress(now: Date = new Date()): BeaconWeeklyProgress {
  const weekKey = getWeekKey(now);
  const empty: BeaconWeeklyProgress = {
    weekKey,
    progress: 0,
    startedAt: Date.now(),
    completedAt: null,
    claimed: false,
    durationSec: 0,
  };
  if (typeof localStorage === "undefined") return empty;
  try {
    const raw = localStorage.getItem(BEACON_WEEKLY_KEY);
    if (!raw) return empty;
    const prog = JSON.parse(raw) as BeaconWeeklyProgress;
    if (prog.weekKey !== weekKey) return empty; // 新的一周，重置
    return prog;
  } catch {
    return empty;
  }
}

/** 保存本周进度 */
export function saveWeeklyProgress(prog: BeaconWeeklyProgress): void {
  if (typeof localStorage === "undefined") return;
  localStorage.setItem(BEACON_WEEKLY_KEY, JSON.stringify(prog));
}

/** 增量更新周挑战进度，返回新进度 + 是否刚完成 */
export function addWeeklyProgress(
  current: BeaconWeeklyProgress,
  challenge: BeaconWeeklyChallenge,
  delta: number
): { progress: BeaconWeeklyProgress; justCompleted: boolean } {
  const newProgressVal = Math.min(challenge.goal, current.progress + delta);
  const justCompleted =
    current.completedAt === null && newProgressVal >= challenge.goal;
  const completedAt = justCompleted ? Date.now() : current.completedAt;
  const durationSec =
    completedAt !== null
      ? Math.floor((completedAt - current.startedAt) / 1000)
      : current.durationSec;
  const next: BeaconWeeklyProgress = {
    ...current,
    progress: newProgressVal,
    completedAt,
    durationSec,
  };
  saveWeeklyProgress(next);
  return { progress: next, justCompleted };
}

/** 领取周挑战奖励：返回奖励数值 + 推送排行榜 */
export function claimWeeklyReward(
  challenge: BeaconWeeklyChallenge,
  progress: BeaconWeeklyProgress
): {
  rewardInsight: number;
  rewardContact: number;
  score: number;
  leaderboard: BeaconScoreEntry[];
} {
  if (progress.claimed || progress.completedAt === null) {
    return {
      rewardInsight: 0,
      rewardContact: 0,
      score: 0,
      leaderboard: loadLeaderboard(),
    };
  }
  // 借用 computeBeaconScore：把 weekly 包装成 daily 接口（dateKey 字段不影响计分逻辑）
  const score = computeBeaconScore(
    { ...(challenge as unknown as BeaconDailyChallenge), dateKey: challenge.weekKey },
    progress.progress,
    progress.durationSec
  );
  const entry: BeaconScoreEntry = {
    timestamp: Date.now(),
    dateKey: challenge.weekKey,
    challenge: challenge.type,
    difficulty: challenge.difficulty,
    progress: progress.progress / challenge.goal,
    score,
    durationSec: progress.durationSec,
    isWeekly: true,
  };
  const leaderboard = pushLeaderboardEntry(entry);
  const updated: BeaconWeeklyProgress = { ...progress, claimed: true };
  saveWeeklyProgress(updated);
  return {
    rewardInsight: challenge.rewardInsight,
    rewardContact: challenge.rewardContact,
    score,
    leaderboard,
  };
}

/** 距离下周一 UTC 0 点的毫秒数（用于周挑战倒计时） */
export function msUntilNextWeek(now: Date = new Date()): number {
  const dayNum = (now.getUTCDay() + 6) % 7; // 0 = Mon
  const mondayThisWeek = Date.UTC(
    now.getUTCFullYear(),
    now.getUTCMonth(),
    now.getUTCDate() - dayNum,
    0,
    0,
    0
  );
  const nextMonday = mondayThisWeek + 7 * 86400000;
  return Math.max(0, nextMonday - now.getTime());
}

// ===========================================================================
// 信标链（BEACON CHAIN）— v0.8
// 连续完成日挑战形成"链"，达成里程碑（3/7/14/30 天）领取递增大奖。
// 断链有宽容机制（1 天 miss 不断链，用"信标续命"概念），每条链只能用 1 次。
// ===========================================================================

/** 信标链 localStorage key */
export const BEACON_CHAIN_KEY = "echo-nexus-beacon-chain-v1";

/** 里程碑天数 */
export const BEACON_CHAIN_MILESTONES = [3, 7, 14, 30] as const;

/** 里程碑奖励配置 */
export interface BeaconChainReward {
  milestone: number;
  rewardInsight: number;
  rewardContact: number;
  label: string;
}

export const BEACON_CHAIN_REWARDS: BeaconChainReward[] = [
  { milestone: 3, rewardInsight: 50, rewardContact: 5, label: "三日谐振" },
  { milestone: 7, rewardInsight: 120, rewardContact: 12, label: "七日回响" },
  { milestone: 14, rewardInsight: 280, rewardContact: 28, label: "半月星潮" },
  { milestone: 30, rewardInsight: 680, rewardContact: 68, label: "满月飞升" },
];

/** 信标链状态 */
export interface BeaconChainState {
  /** 上次完成日（YYYY-MM-DD） */
  lastCompletedDateKey: string;
  /** 当前连续天数 */
  currentStreak: number;
  /** 历史最长 */
  longestStreak: number;
  /** 累计完成总数 */
  totalCompletions: number;
  /** 本周期已用续命数（上限 1） */
  graceUsed: number;
  /** 已领取的里程碑数组 */
  milestonesClaimed: number[];
}

/** 读取信标链状态 */
export function loadChainState(): BeaconChainState {
  const fresh = (): BeaconChainState => ({
    lastCompletedDateKey: "",
    currentStreak: 0,
    longestStreak: 0,
    totalCompletions: 0,
    graceUsed: 0,
    milestonesClaimed: [],
  });
  if (typeof localStorage === "undefined") return fresh();
  try {
    const raw = localStorage.getItem(BEACON_CHAIN_KEY);
    if (!raw) return fresh();
    const s = JSON.parse(raw) as Partial<BeaconChainState>;
    return {
      lastCompletedDateKey: s.lastCompletedDateKey ?? "",
      currentStreak: s.currentStreak ?? 0,
      longestStreak: s.longestStreak ?? 0,
      totalCompletions: s.totalCompletions ?? 0,
      graceUsed: s.graceUsed ?? 0,
      milestonesClaimed: Array.isArray(s.milestonesClaimed)
        ? [...s.milestonesClaimed]
        : [],
    };
  } catch {
    return fresh();
  }
}

/** 保存信标链状态 */
export function saveChainState(state: BeaconChainState): void {
  if (typeof localStorage === "undefined") return;
  localStorage.setItem(BEACON_CHAIN_KEY, JSON.stringify(state));
}

/** dateKey → UTC 0 点时间戳 */
function dateKeyToTimestamp(dateKey: string): number {
  const [y, m, d] = dateKey.split("-").map(Number);
  return Date.UTC(y, m - 1, d, 0, 0, 0);
}

/** 计算 b - a 相差的天数（UTC 0 点对齐） */
function dateKeyDiffDays(a: string, b: string): number {
  if (!a || !b) return Number.MAX_SAFE_INTEGER;
  return Math.round((dateKeyToTimestamp(b) - dateKeyToTimestamp(a)) / 86400000);
}

/**
 * 记录一次日挑战完成（核心逻辑）。
 * - dateKey === lastCompletedDateKey：同一天重复完成，忽略，返回 newMilestones: []
 * - dateKey 是 lastCompletedDateKey 的次日：currentStreak++
 * - dateKey 是 lastCompletedDateKey 的后两天（隔了一天 miss）且 graceUsed < 1：续命一次，currentStreak++
 * - 其他：currentStreak = 1（断链重来），graceUsed = 0
 * 更新 longestStreak 与 totalCompletions。
 * @returns { state, newMilestones } 刚达成但未领取的里程碑数组
 */
export function recordChainCompletion(dateKey: string): {
  state: BeaconChainState;
  newMilestones: number[];
} {
  const state = loadChainState();

  // 同一天重复完成：忽略
  if (state.lastCompletedDateKey === dateKey) {
    return { state, newMilestones: [] };
  }

  let next: BeaconChainState;

  if (state.lastCompletedDateKey === "") {
    // 首次完成
    next = {
      ...state,
      lastCompletedDateKey: dateKey,
      currentStreak: 1,
      longestStreak: Math.max(state.longestStreak, 1),
      totalCompletions: state.totalCompletions + 1,
    };
  } else {
    const diff = dateKeyDiffDays(state.lastCompletedDateKey, dateKey);
    if (diff === 1) {
      // 次日：链 +1
      const newStreak = state.currentStreak + 1;
      next = {
        ...state,
        lastCompletedDateKey: dateKey,
        currentStreak: newStreak,
        longestStreak: Math.max(state.longestStreak, newStreak),
        totalCompletions: state.totalCompletions + 1,
      };
    } else if (diff === 2 && state.graceUsed < 1) {
      // 隔一天 miss，续命一次
      const newStreak = state.currentStreak + 1;
      next = {
        ...state,
        lastCompletedDateKey: dateKey,
        currentStreak: newStreak,
        longestStreak: Math.max(state.longestStreak, newStreak),
        totalCompletions: state.totalCompletions + 1,
        graceUsed: state.graceUsed + 1,
      };
    } else {
      // 断链重来
      next = {
        ...state,
        lastCompletedDateKey: dateKey,
        currentStreak: 1,
        totalCompletions: state.totalCompletions + 1,
        graceUsed: 0,
        longestStreak: Math.max(state.longestStreak, 1),
      };
    }
  }

  // 检查新里程碑（刚达成但未领取）
  const newMilestones: number[] = [];
  for (const m of BEACON_CHAIN_MILESTONES) {
    if (
      next.currentStreak >= m &&
      !next.milestonesClaimed.includes(m)
    ) {
      newMilestones.push(m);
    }
  }

  saveChainState(next);
  return { state: next, newMilestones };
}

/** 领取里程碑奖励，加入 milestonesClaimed */
export function claimChainMilestone(milestone: number): {
  rewardInsight: number;
  rewardContact: number;
  label: string;
  state: BeaconChainState;
} {
  const reward = BEACON_CHAIN_REWARDS.find((r) => r.milestone === milestone);
  const state = loadChainState();
  if (
    !reward ||
    state.milestonesClaimed.includes(milestone) ||
    state.currentStreak < milestone
  ) {
    return { rewardInsight: 0, rewardContact: 0, label: "", state };
  }
  const next: BeaconChainState = {
    ...state,
    milestonesClaimed: [...state.milestonesClaimed, milestone],
  };
  saveChainState(next);
  return {
    rewardInsight: reward.rewardInsight,
    rewardContact: reward.rewardContact,
    label: reward.label,
    state: next,
  };
}

/** 返回下一个目标里程碑（如 streak=5 → 7；streak=30+ → null） */
export function getNextMilestone(streak: number): number | null {
  for (const m of BEACON_CHAIN_MILESTONES) {
    if (streak < m) return m;
  }
  return null;
}

/**
 * 返回信标链进度信息（用于 UI 进度条）。
 * - current：当前连续天数
 * - next：下一个目标里程碑（null 表示已通关全部）
 * - progressPct：当前进度（基于上一个里程碑 → 下一个里程碑）
 */
export function getChainProgress(streak: number): {
  current: number;
  next: number | null;
  prev: number;
  progressPct: number;
} {
  const next = getNextMilestone(streak);
  let prev = 0;
  for (const m of BEACON_CHAIN_MILESTONES) {
    if (streak >= m) prev = m;
  }
  if (next === null) {
    return { current: streak, next: null, prev, progressPct: 100 };
  }
  const span = next - prev;
  const done = streak - prev;
  const pct = span > 0 ? Math.round((done / span) * 100) : 100;
  return {
    current: streak,
    next,
    prev,
    progressPct: Math.min(100, Math.max(0, pct)),
  };
}