"use client";

import { create } from "zustand";
import { persist } from "zustand/middleware";
import type { GammeCode, GridFilters, GridSummary, ProductRow } from "@/types/grid";

interface GridState {
    /** Source data from server */
    rows: ProductRow[];
    /** Index O(1) pour les lookups par codein (Map<codein, ProductRow>) */
    rowsIndex: Map<string, ProductRow>;
    /** Draft edits: codein → new GammeCode */
    draftChanges: Record<string, GammeCode>;
    filters: GridFilters;
    summary: GridSummary;
    displayDensity: "compact" | "normal" | "comfortable";
    /** The active URL search parameters (e.g. ?fournisseur=123&magasin=TOTAL) */
    activeGridQuery: string;
    /** Persisted column visibility state */
    columnVisibility: Record<string, boolean>;
    /** Persisted column sizing state */
    columnSizing: Record<string, number>;

    /** Currently displayed store: "TOTAL" | "292" | "579" */
    activeMagasin: string;
    setActiveMagasin: (code: string) => void;

    // Actions
    setRows: (rows: ProductRow[]) => void;
    appendRows: (newRows: ProductRow[]) => void;
    setDraftGamme: (codein: string, gamme: GammeCode) => void;
    resetDrafts: () => void;
    /** Clear specific draft changes by codein */
    clearDrafts: (codeins: string[]) => void;
    /** Apply saved drafts onto row.codeGamme so change indicators persist after save */
    applyDraftsToRows: (draftsToApply: Record<string, GammeCode>) => void;
    setFilter: (key: keyof GridFilters, value: string | null) => void;
    setDisplayDensity: (density: "compact" | "normal" | "comfortable") => void;
    setActiveGridQuery: (query: string) => void;
    restoreSnapshot: (changes: Record<string, GammeCode>) => void;
    batchSetDraftGamme: (changes: Record<string, GammeCode>) => void;
    setColumnVisibility: (updater: Record<string, boolean> | ((old: Record<string, boolean>) => Record<string, boolean>)) => void;
    setColumnSizing: (updater: Record<string, number> | ((old: Record<string, number>) => Record<string, number>)) => void;
}

function computeSummary(rows: ProductRow[], drafts: Record<string, GammeCode>, magasin = "TOTAL"): GridSummary {
    const active = rows.filter((r) => {
        const g = drafts[r.codein] ?? r.codeGamme;
        return g !== "Z";
    });
    const getCa    = (r: ProductRow) => magasin === "TOTAL" ? (r.totalCa     ?? 0) : (r.caByStore?.[magasin]       ?? 0);
    const getQte   = (r: ProductRow) => magasin === "TOTAL" ? (r.totalQuantite ?? 0) : (r.quantiteByStore?.[magasin] ?? 0);
    const getMarge = (r: ProductRow) => magasin === "TOTAL" ? (r.totalMarge  ?? 0) : (r.margeByStore?.[magasin]    ?? 0);
    const totalCa    = active.reduce((s, r) => s + getCa(r),    0);
    const totalMarge = active.reduce((s, r) => s + getMarge(r), 0);
    return {
        totalProducts: rows.length,
        totalRows: active.length,
        totalQuantite: active.reduce((s, r) => s + getQte(r), 0),
        totalCa,
        totalMarge,
        tauxMargeGlobal: totalCa > 0 ? (totalMarge / totalCa) * 100 : 0,
    };
}

export const useGridStore = create<GridState>()(
    persist(
        (set, get) => ({
            rows: [],
            rowsIndex: new Map(),
            activeMagasin: "TOTAL",
            draftChanges: {},
            filters: {
                magasin: null,
                codeFournisseur: null,
                code1: null,
                code2: null,
                code3: null,
                codeGamme: null,
                search: "",
            },
            summary: {
                totalProducts: 0,
                totalRows: 0,
                totalQuantite: 0,
                totalCa: 0,
                totalMarge: 0,
                tauxMargeGlobal: 0,
            },
            displayDensity: "normal",
            activeGridQuery: "",
            columnVisibility: {},
            columnSizing: {},

            setActiveMagasin: (code) => {
                const { rows, draftChanges } = get();
                set({ activeMagasin: code, summary: computeSummary(rows, draftChanges, code) });
            },

            setRows: (rows) => {
                // Construire l'index en O(n) une seule fois au lieu de O(n) à chaque lookup.
                const rowsIndex = new Map<string, ProductRow>(rows.map(r => [r.codein, r]));
                set({ rows, rowsIndex, summary: computeSummary(rows, get().draftChanges, get().activeMagasin) });
            },

            appendRows: (newRows) => {
                const { rows, rowsIndex, draftChanges, activeMagasin } = get();
                // O(n) uniquement sur les nouveaux éléments, au lieu de re-calculer les 130k existants
                const mergedRows = [...rows, ...newRows];
                newRows.forEach(r => rowsIndex.set(r.codein, r));
                set({
                    rows: mergedRows,
                    rowsIndex,
                    summary: computeSummary(mergedRows, draftChanges, activeMagasin)
                });
            },

            setDraftGamme: (codein, gamme) => {
                const { rows, rowsIndex, draftChanges: oldDrafts } = get();
                // Lookup O(1) via l'index au lieu de O(n) via .find()
                const originalRow = rowsIndex.get(codein);
                const originalGamme = originalRow?.codeGamme;

                const draftChanges = { ...oldDrafts };

                if (gamme === originalGamme) {
                    // If the new value matches initial, remove it from drafts
                    delete draftChanges[codein];
                } else {
                    // Otherwise, record the change
                    draftChanges[codein] = gamme;
                }

                set({ draftChanges, summary: computeSummary(rows, draftChanges, get().activeMagasin) });
            },

            resetDrafts: () => {
                set({ draftChanges: {}, summary: computeSummary(get().rows, {}, get().activeMagasin) });
            },
            clearDrafts: (codeins) => {
                const draftChanges = { ...get().draftChanges };
                codeins.forEach((id) => delete draftChanges[id]);
                set({ draftChanges, summary: computeSummary(get().rows, draftChanges, get().activeMagasin) });
            },
            /** Apply saved drafts onto row.codeGamme so isModified works after clearing drafts */
            applyDraftsToRows: (draftsToApply: Record<string, GammeCode>) => {
                const rows = get().rows.map(r => {
                    const newGamme = draftsToApply[r.codein];
                    if (newGamme !== undefined) {
                        return { ...r, codeGamme: newGamme };
                    }
                    return r;
                });
                set({ rows });
            },
            setFilter: (key, value) => {
                set((state) => ({ ...state, filters: { ...state.filters, [key]: value } }));
            },
            setDisplayDensity: (density) => set({ displayDensity: density }),
            setActiveGridQuery: (query) => set({ activeGridQuery: query }),
            restoreSnapshot: (changes) => {
                set({ draftChanges: changes, summary: computeSummary(get().rows, changes, get().activeMagasin) });
            },

            batchSetDraftGamme: (newChanges) => {
                const { rows, rowsIndex, draftChanges: oldDrafts } = get();
                const updatedDrafts = { ...oldDrafts };

                Object.entries(newChanges).forEach(([codein, gamme]) => {
                    // Lookup O(1) via l'index au lieu de O(n) via .find()
                    const originalRow = rowsIndex.get(codein);
                    const originalGamme = originalRow?.codeGamme;

                    if (gamme === originalGamme) {
                        delete updatedDrafts[codein];
                    } else {
                        updatedDrafts[codein] = gamme;
                    }
                });

                set({ draftChanges: updatedDrafts, summary: computeSummary(rows, updatedDrafts, get().activeMagasin) });
            },

            setColumnVisibility: (updater) => {
                set((state) => ({
                    columnVisibility: typeof updater === 'function' ? updater(state.columnVisibility) : updater
                }));
            },
            setColumnSizing: (updater) => {
                set((state) => ({
                    columnSizing: typeof updater === 'function' ? updater(state.columnSizing) : updater
                }));
            },
        }),
        {
            name: "collectflow-grid-storage",
            // Only persist filters, display density, drafts, active grid query, and column visibility/sizing
            partialize: (state) => ({
                filters: state.filters,
                displayDensity: state.displayDensity,
                draftChanges: state.draftChanges,
                activeGridQuery: state.activeGridQuery,
                columnVisibility: state.columnVisibility,
                columnSizing: state.columnSizing,
            }),
        }
    )
);