import type {
  CourseList,
  CourseListParams,
  CourseRow,
  FitnessGroup,
  TimeSlot,
  YesNo,
} from "@/api/types";
import { defineStore } from "pinia";
import { computed, ref } from "vue";
import {
  fetchCourseList,
  fetchGroup,
  fetchMorning,
  fetchNight,
  fetchNoon,
} from "@/api/course";

/** 後端尚未完成，預設走前端模擬資料；設定 VITE_USE_MOCK=false 即改打真實 API */
const USE_MOCK = import.meta.env.VITE_USE_MOCK !== "false";

/** 模擬網路延遲，讓載入狀態在開發時可被觀察到 */
const MOCK_DELAY = 300;

export interface GroupMeta {
  label: string;
  color: string;
  /** 以活動強度遞增的圖示表達組別高低，讓組別不只靠顏色辨識 */
  icon: string;
  description: string;
}

/** 組別的顯示資訊，文案取自 doc/課程說明.md */
export const GROUP_META: Record<FitnessGroup, GroupMeta> = {
  low: {
    label: "低體適能",
    color: "warning",
    icon: "mdi-walk",
    description:
      "肌力、平衡與心肺功能較弱，以降低跌倒風險、重建日常生活功能為優先。",
  },
  medium: {
    label: "中體適能",
    color: "info",
    icon: "mdi-run",
    description:
      "尚未失能但已出現部分衰退，重點在累積功能儲備、增加肌肉量與心肺能力。",
  },
  high: {
    label: "高體適能",
    color: "success",
    icon: "mdi-run-fast",
    description:
      "功能儲備高、跌倒風險低，目標是延緩衰退速度並長期維持既有功能。",
  },
};

/**
 * 三組一週課表，內容逐格轉錄自 doc/課程表.png。
 * 後端完成後這份資料會由第 5 支 API 提供。
 */
function createCourseTable(): Record<FitnessGroup, CourseRow[]> {
  return {
    low: [
      {
        day: 1,
        morning: "慢走 15 分鐘",
        noon: "正常飲食，多吃蔬菜與蛋白質",
        night: "坐站訓練 10 次 ×2 組＋伸展 10 分鐘",
      },
      {
        day: 2,
        morning: "公園散步 20 分鐘",
        noon: "1 顆蛋＋豆漿",
        night: "單腳站立和平衡訓練 15 分鐘",
      },
      {
        day: 3,
        morning: "慢走 15 分鐘",
        noon: "魚肉與青菜",
        night: "扶牆踮腳 15 次 ×2 組",
      },
      {
        day: 4,
        morning: "休閒散步 20 分鐘",
        noon: "補充水果",
        night: "伸展運動 10 分鐘",
      },
      {
        day: 5,
        morning: "慢走 20 分鐘",
        noon: "雞肉與蔬菜",
        night: "坐站訓練＋平衡訓練",
      },
      {
        day: 6,
        morning: "腳踏車或散步 30 分鐘",
        noon: "均衡飲食",
        night: "全身伸展",
      },
      { day: 7, morning: "輕鬆散步", noon: "與家人共餐", night: "早睡休息" },
    ],
    medium: [
      {
        day: 1,
        morning: "快走 30 分鐘",
        noon: "高蛋白午餐",
        night: "深蹲 15 次 ×3 組",
      },
      {
        day: 2,
        morning: "騎腳踏車 40 分鐘",
        noon: "水果與豆類",
        night: "伸展 15 分鐘",
      },
      {
        day: 3,
        morning: "快走 30 分鐘",
        noon: "魚肉與蔬菜",
        night: "彈力帶訓練",
      },
      {
        day: 4,
        morning: "游泳或太極 40 分鐘",
        noon: "均衡飲食",
        night: "核心訓練 15 分鐘",
      },
      {
        day: 5,
        morning: "快走 30 分鐘",
        noon: "高蛋白午餐",
        night: "深蹲＋彈力帶",
      },
      {
        day: 6,
        morning: "郊山健行 60 分鐘",
        noon: "補充水分",
        night: "輕鬆散步",
      },
      { day: 7, morning: "休息", noon: "家人聚餐", night: "伸展 10 分鐘" },
    ],
    high: [
      {
        day: 1,
        morning: "重量訓練 60 分鐘",
        noon: "蛋白質與蔬菜",
        night: "散步 20 分鐘",
      },
      {
        day: 2,
        morning: "快走或慢跑 45 分鐘",
        noon: "水果與堅果",
        night: "核心訓練 20 分鐘",
      },
      {
        day: 3,
        morning: "平衡與敏捷訓練 40 分鐘",
        noon: "均衡飲食",
        night: "伸展 15 分鐘",
      },
      {
        day: 4,
        morning: "重量訓練 60 分鐘",
        noon: "高蛋白午餐",
        night: "散步 20 分鐘",
      },
      {
        day: 5,
        morning: "間歇跑 30 分鐘",
        noon: "補充水分",
        night: "輕量伸展",
      },
      {
        day: 6,
        morning: "登山、羽球或游泳 90 分鐘",
        noon: "魚類與蔬菜",
        night: "放鬆休息",
      },
      {
        day: 7,
        morning: "輕鬆散步 30 分鐘",
        noon: "家人聚餐",
        night: "早睡恢復",
      },
    ],
  };
}

function delay(ms: number) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

/** 模擬後端依 Y/N 篩選時段欄位的行為 */
function mockCourseList(params: CourseListParams): CourseList {
  return createCourseTable()[params.group].map((row) => {
    const filtered: CourseRow = { day: row.day };

    if (params.morning === "Y") {
      filtered.morning = row.morning;
    }
    if (params.noon === "Y") {
      filtered.noon = row.noon;
    }
    if (params.night === "Y") {
      filtered.night = row.night;
    }

    return filtered;
  });
}

export const useCourseStore = defineStore("course", () => {
  const group = ref<FitnessGroup>("medium");
  const morning = ref<YesNo>("Y");
  const noon = ref<YesNo>("Y");
  const night = ref<YesNo>("Y");
  const courseList = ref<CourseList>([]);
  const loading = ref(false);
  const error = ref("");

  const groupMeta = computed(() => GROUP_META[group.value]);

  /** 目前被選取的時段，供畫面判斷要顯示哪些欄位 */
  const selectedSlots = computed<TimeSlot[]>(() => {
    const slots: TimeSlot[] = [];

    if (morning.value === "Y") {
      slots.push("morning");
    }
    if (noon.value === "Y") {
      slots.push("noon");
    }
    if (night.value === "Y") {
      slots.push("night");
    }

    return slots;
  });

  const hasCourse = computed(
    () => selectedSlots.value.length > 0 && courseList.value.length > 0,
  );

  /** 前 4 支 API：平行取得組別與三個時段設定 */
  async function loadPreferences() {
    if (USE_MOCK) {
      await delay(MOCK_DELAY);
      group.value = "medium";
      morning.value = "Y";
      noon.value = "Y";
      night.value = "Y";
      return;
    }

    // 真實後端：course/group 由登入 Cookie 識別使用者；
    // course/morning、noon、night 需要 group，兩者有相依順序。
    const groupValue = await fetchGroup();

    const [morningValue, noonValue, nightValue] = await Promise.all([
      fetchMorning(groupValue),
      fetchNoon(groupValue),
      fetchNight(groupValue),
    ]);

    group.value = groupValue;
    morning.value = morningValue;
    noon.value = noonValue;
    night.value = nightValue;
  }

  /** 第 5 支 API：以前 4 個值為參數取得課表 */
  async function loadCourseList() {
    const params: CourseListParams = {
      group: group.value,
      morning: morning.value,
      noon: noon.value,
      night: night.value,
    };

    if (USE_MOCK) {
      await delay(MOCK_DELAY);
      courseList.value = mockCourseList(params);
      return;
    }

    courseList.value = await fetchCourseList(params);
  }

  /** 頁面進入時呼叫：先取設定再取課表 */
  async function loadAll() {
    loading.value = true;
    error.value = "";

    try {
      await loadPreferences();
      await loadCourseList();
    } catch (error_) {
      error.value =
        error_ instanceof Error
          ? error_.message
          : "課程資料載入失敗，請稍後再試。";
      courseList.value = [];
    } finally {
      loading.value = false;
    }
  }

  /** 使用者切換時段後重新取課表 */
  async function setSlot(slot: TimeSlot, value: YesNo) {
    const target = { morning, noon, night }[slot];

    if (target.value === value) {
      return;
    }

    target.value = value;
    loading.value = true;
    error.value = "";

    try {
      await loadCourseList();
    } catch (error_) {
      error.value =
        error_ instanceof Error
          ? error_.message
          : "課程資料載入失敗，請稍後再試。";
      courseList.value = [];
    } finally {
      loading.value = false;
    }
  }

  return {
    group,
    morning,
    noon,
    night,
    courseList,
    loading,
    error,
    groupMeta,
    selectedSlots,
    hasCourse,
    loadAll,
    loadCourseList,
    loadPreferences,
    setSlot,
  };
});