"use client";

import { useCallback, useEffect, useState } from "react";

export type HeatmapColorScheme = "green-red" | "blue-orange" | "purple-yellow" | "mono";

export interface AppPreferences {
  /** Hide allocations that belong to COMPLETED or CANCELLED projects. Default: true. */
  hideCompletedProjects: boolean;
  /**
   * Timeline row rendering style.
   * "strip"   — horizontal colored blocks per allocation (classic Gantt) + load graph
   * "bar"     — stacked vertical bars per day showing hours by project
   * "heatmap" — strips overlaid with a green→red utilization colour per day column
   */
  timelineDisplayMode: "strip" | "bar" | "heatmap";
  /** Color palette used for heatmap overlays and bar-mode project view bars. */
  heatmapColorScheme: HeatmapColorScheme;
  /** Show open demand / placeholder entries by default when loading the timeline. Default: true. */
  showDemandProjects: boolean;
  /** Blink overbooked days (>8h) as a warning on the timeline. Default: false. */
  blinkOverbookedDays: boolean;
}

const STORAGE_KEY = "capakraken_prefs";
const CHANGE_EVENT = "capakraken-prefs-changed";

const DEFAULT: AppPreferences = {
  hideCompletedProjects: true,
  timelineDisplayMode: "strip",
  heatmapColorScheme: "green-red",
  showDemandProjects: true,
  blinkOverbookedDays: false,
};

export function readAppPreferences(): AppPreferences {
  if (typeof window === "undefined") return DEFAULT;
  try {
    const raw = localStorage.getItem(STORAGE_KEY);
    if (!raw) return DEFAULT;
    return { ...DEFAULT, ...(JSON.parse(raw) as Partial<AppPreferences>) };
  } catch {
    return DEFAULT;
  }
}

function saveAppPreferences(prefs: AppPreferences) {
  localStorage.setItem(STORAGE_KEY, JSON.stringify(prefs));
  // Broadcast to all hook instances in the same tab
  window.dispatchEvent(new CustomEvent<AppPreferences>(CHANGE_EVENT, { detail: prefs }));
}

export function useAppPreferences() {
  const [prefs, setPrefs] = useState<AppPreferences>(DEFAULT);

  useEffect(() => {
    // Sync from storage on mount
    setPrefs(readAppPreferences());

    // Keep in sync when any hook instance saves a change
    function handleChange(e: Event) {
      setPrefs((e as CustomEvent<AppPreferences>).detail);
    }
    window.addEventListener(CHANGE_EVENT, handleChange);
    return () => window.removeEventListener(CHANGE_EVENT, handleChange);
  }, []);

  const setHideCompletedProjects = useCallback((value: boolean) => {
    setPrefs((prev) => {
      const next = { ...prev, hideCompletedProjects: value };
      saveAppPreferences(next);
      return next;
    });
  }, []);

  const setTimelineDisplayMode = useCallback((value: AppPreferences["timelineDisplayMode"]) => {
    setPrefs((prev) => {
      const next = { ...prev, timelineDisplayMode: value };
      saveAppPreferences(next);
      return next;
    });
  }, []);

  const setHeatmapColorScheme = useCallback((value: HeatmapColorScheme) => {
    setPrefs((prev) => {
      const next = { ...prev, heatmapColorScheme: value };
      saveAppPreferences(next);
      return next;
    });
  }, []);

  const setShowDemandProjects = useCallback((value: boolean) => {
    setPrefs((prev) => {
      const next = { ...prev, showDemandProjects: value };
      saveAppPreferences(next);
      return next;
    });
  }, []);

  const setBlinkOverbookedDays = useCallback((value: boolean) => {
    setPrefs((prev) => {
      const next = { ...prev, blinkOverbookedDays: value };
      saveAppPreferences(next);
      return next;
    });
  }, []);

  return { prefs, setHideCompletedProjects, setTimelineDisplayMode, setHeatmapColorScheme, setShowDemandProjects, setBlinkOverbookedDays };
}