'use client';
export const dynamic = 'force-dynamic';


import React, { useState, useEffect, useRef } from 'react';
import { DataTable } from 'primereact/datatable';
import { Column } from 'primereact/column';
import { Button } from 'primereact/button';
import { InputText } from 'primereact/inputtext';
import { Card } from 'primereact/card';
import { Toast } from 'primereact/toast';
import { Toolbar } from 'primereact/toolbar';
import { Tag } from 'primereact/tag';
import { Dialog } from 'primereact/dialog';
import { Calendar } from 'primereact/calendar';
import { InputTextarea } from 'primereact/inputtextarea';
import { InputNumber } from 'primereact/inputnumber';
import { Dropdown } from 'primereact/dropdown';
import { Chip } from 'primereact/chip';
import { Divider } from 'primereact/divider';
import { factureService, clientService } from '../../../../services/api';
import { formatDate, formatCurrency } from '../../../../utils/formatters';
import type { Facture } from '../../../../types/btp';
import { StatutFacture, TypeFacture } from '../../../../types/btp';

const FacturesAvoirsPage = () => {
    const [avoirs, setAvoirs] = useState<Facture[]>([]);
    const [clients, setClients] = useState<any[]>([]);
    const [loading, setLoading] = useState(true);
    const [globalFilter, setGlobalFilter] = useState('');
    const [selectedAvoirs, setSelectedAvoirs] = useState<Facture[]>([]);
    const [avoirDialog, setAvoirDialog] = useState(false);
    const [selectedAvoir, setSelectedAvoir] = useState<Facture | null>(null);
    const [isCreating, setIsCreating] = useState(false);
    const [avoir, setAvoir] = useState<Partial<Facture>>({
        id: '',
        numero: '',
        dateEmission: new Date().toISOString(),
        dateEcheance: new Date(Date.now() + 30 * 24 * 60 * 60 * 1000).toISOString(),
        datePaiement: null,
        objet: '',
        description: '',
        montantHT: 0,
        montantTTC: 0,
        tauxTVA: 20,
        statut: StatutFacture.ENVOYEE,
        typeFacture: TypeFacture.AVOIR,
        actif: true,
        client: null,
        chantier: null,
        devis: null,
        lignes: []
    });
    const [submitted, setSubmitted] = useState(false);
    const toast = useRef<Toast>(null);
    const dt = useRef<DataTable<Facture[]>>(null);

    const avoirReasons = [
        { label: 'Erreur de facturation', value: 'ERREUR_FACTURATION' },
        { label: 'Retour de marchandise', value: 'RETOUR_MARCHANDISE' },
        { label: 'Annulation partielle', value: 'ANNULATION_PARTIELLE' },
        { label: 'Remise commerciale', value: 'REMISE_COMMERCIALE' },
        { label: 'Défaut de conformité', value: 'DEFAUT_CONFORMITE' },
        { label: 'Geste commercial', value: 'GESTE_COMMERCIAL' }
    ];

    useEffect(() => {
        loadAvoirs();
        loadClients();
    }, []);

    const loadAvoirs = async () => {
        try {
            setLoading(true);
            const data = await factureService.getAll();
            // Filtrer les avoirs
            const avoirsList = data.filter(facture => facture.typeFacture === TypeFacture.AVOIR);
            setAvoirs(avoirsList);
        } catch (error) {
            console.error('Erreur lors du chargement des avoirs:', error);
            toast.current?.show({
                severity: 'error',
                summary: 'Erreur',
                detail: 'Impossible de charger les avoirs',
                life: 3000
            });
        } finally {
            setLoading(false);
        }
    };

    const loadClients = async () => {
        try {
            const data = await clientService.getAll();
            setClients(data.map(client => ({
                label: `${client.prenom} ${client.nom}${client.entreprise ? ' - ' + client.entreprise : ''}`,
                value: client.id,
                client: client
            })));
        } catch (error) {
            console.error('Erreur lors du chargement des clients:', error);
        }
    };

    const getAvoirReason = (description: string) => {
        // Simuler la détection de la raison à partir de la description
        if (description.toLowerCase().includes('erreur')) return 'ERREUR_FACTURATION';
        if (description.toLowerCase().includes('retour')) return 'RETOUR_MARCHANDISE';
        if (description.toLowerCase().includes('annulation')) return 'ANNULATION_PARTIELLE';
        if (description.toLowerCase().includes('remise')) return 'REMISE_COMMERCIALE';
        if (description.toLowerCase().includes('défaut')) return 'DEFAUT_CONFORMITE';
        return 'GESTE_COMMERCIAL';
    };

    const getReasonLabel = (reason: string) => {
        const reasonObj = avoirReasons.find(r => r.value === reason);
        return reasonObj ? reasonObj.label : 'Autre';
    };

    const getAvoirSeverity = (reason: string) => {
        switch (reason) {
            case 'ERREUR_FACTURATION':
            case 'DEFAUT_CONFORMITE':
                return 'danger';
            case 'RETOUR_MARCHANDISE':
            case 'ANNULATION_PARTIELLE':
                return 'warning';
            case 'REMISE_COMMERCIALE':
            case 'GESTE_COMMERCIAL':
                return 'info';
            default:
                return 'secondary';
        }
    };

    const openNew = () => {
        setAvoir({
            id: '',
            numero: '',
            dateEmission: new Date().toISOString(),
            dateEcheance: new Date(Date.now() + 30 * 24 * 60 * 60 * 1000).toISOString(),
            datePaiement: null,
            objet: '',
            description: '',
            montantHT: 0,
            montantTTC: 0,
            tauxTVA: 20,
            statut: StatutFacture.ENVOYEE,
            typeFacture: TypeFacture.AVOIR,
            actif: true,
            client: null,
            chantier: null,
            devis: null,
            lignes: []
        });
        setSubmitted(false);
        setIsCreating(true);
        setAvoirDialog(true);
    };

    const viewDetails = (avoirItem: Facture) => {
        setSelectedAvoir(avoirItem);
        setIsCreating(false);
        setAvoirDialog(true);
    };

    const hideDialog = () => {
        setSubmitted(false);
        setAvoirDialog(false);
        setSelectedAvoir(null);
        setIsCreating(false);
    };

    const saveAvoir = async () => {
        setSubmitted(true);

        if (avoir.objet.trim() && avoir.client && avoir.montantHT > 0) {
            try {
                const avoirToSave = {
                    ...avoir,
                    client: avoir.client ? { id: avoir.client } : null,
                    montantTTC: avoir.montantHT * (1 + avoir.tauxTVA / 100),
                    numero: `AV-${new Date().getFullYear()}-${String(avoirs.length + 1).padStart(4, '0')}`
                };

                // TODO: Implémenter la création d'avoir quand l'API sera disponible
                console.log('Création d\'avoir:', avoirToSave);

                // Simulation
                setAvoirs(prev => [...prev, { ...avoirToSave, id: Date.now().toString() } as unknown as Facture]);
                
                setAvoirDialog(false);
                
                toast.current?.show({
                    severity: 'success',
                    summary: 'Succès',
                    detail: 'Avoir créé avec succès (simulation)',
                    life: 3000
                });
            } catch (error) {
                console.error('Erreur lors de la sauvegarde:', error);
                toast.current?.show({
                    severity: 'error',
                    summary: 'Erreur',
                    detail: 'Impossible de sauvegarder l\'avoir',
                    life: 3000
                });
            }
        }
    };

    const exportCSV = () => {
        dt.current?.exportCSV();
    };

    const generateAvoirReport = () => {
        const totalAvoirs = avoirs.reduce((sum, a) => sum + (a.montantTTC || 0), 0);
        const reasonStats = {};
        
        avoirs.forEach(a => {
            const reason = getAvoirReason(a.description || '');
            const label = getReasonLabel(reason);
            if (!reasonStats[label]) {
                reasonStats[label] = { count: 0, value: 0 };
            }
            reasonStats[label].count++;
            reasonStats[label].value += a.montantTTC || 0;
        });
        
        const report = `
=== RAPPORT AVOIRS ===
Date du rapport: ${new Date().toLocaleDateString('fr-FR')}

STATISTIQUES GÉNÉRALES:
- Nombre total d'avoirs: ${avoirs.length}
- Montant total des avoirs: ${formatCurrency(totalAvoirs)}
- Montant moyen par avoir: ${formatCurrency(totalAvoirs / (avoirs.length || 1))}

RÉPARTITION PAR MOTIF:
${Object.entries(reasonStats)
    .sort((a: [string, any], b: [string, any]) => b[1].value - a[1].value)
    .map(([reason, data]: [string, any]) => `- ${reason}: ${data.count} avoirs, ${formatCurrency(data.value)} (${Math.round((data.value / totalAvoirs) * 100)}%)`)
    .join('\n')}

ANALYSE PAR MOIS:
${getMonthlyAvoirBreakdown()}

CLIENTS AVEC LE PLUS D'AVOIRS:
${getClientAvoirAnalysis()}

IMPACT SUR LE CHIFFRE D'AFFAIRES:
- Pourcentage du CA en avoirs: ${getCAImpact()}%
- Tendance mensuelle: ${getTrend()}

RECOMMANDATIONS:
- Analyser les causes récurrentes d'avoirs
- Mettre en place des mesures préventives
- Former les équipes pour réduire les erreurs
- Améliorer les processus de contrôle qualité
        `;
        
        const blob = new Blob([report], { type: 'text/plain;charset=utf-8;' });
        const link = document.createElement('a');
        link.href = URL.createObjectURL(blob);
        link.download = `rapport_avoirs_${new Date().toISOString().split('T')[0]}.txt`;
        link.click();
        
        toast.current?.show({
            severity: 'success',
            summary: 'Rapport généré',
            detail: 'Le rapport d\'avoirs a été téléchargé',
            life: 3000
        });
    };

    const getMonthlyAvoirBreakdown = () => {
        const months = {};
        avoirs.forEach(a => {
            const month = new Date(a.dateEmission).toLocaleDateString('fr-FR', { year: 'numeric', month: 'long' });
            if (!months[month]) {
                months[month] = { count: 0, value: 0 };
            }
            months[month].count++;
            months[month].value += a.montantTTC || 0;
        });
        
        return Object.entries(months)
            .sort((a, b) => new Date(a[0]).getTime() - new Date(b[0]).getTime())
            .map(([month, data]: [string, any]) => `- ${month}: ${data.count} avoirs, ${formatCurrency(data.value)}`)
            .join('\n');
    };

    const getClientAvoirAnalysis = () => {
        const clientStats = {};
        avoirs.forEach(a => {
            if (a.client) {
                const clientKey = `${a.client.prenom} ${a.client.nom}`;
                if (!clientStats[clientKey]) {
                    clientStats[clientKey] = { count: 0, value: 0 };
                }
                clientStats[clientKey].count++;
                clientStats[clientKey].value += a.montantTTC || 0;
            }
        });
        
        return Object.entries(clientStats)
            .sort((a: [string, any], b: [string, any]) => b[1].count - a[1].count)
            .slice(0, 5)
            .map(([client, data]: [string, any]) => `- ${client}: ${data.count} avoirs, ${formatCurrency(data.value)}`)
            .join('\n');
    };

    const getCAImpact = () => {
        // Simulation - calcul de l'impact sur le CA
        const totalCA = 500000; // CA simulé
        const totalAvoirs = avoirs.reduce((sum, a) => sum + (a.montantTTC || 0), 0);
        return ((totalAvoirs / totalCA) * 100).toFixed(2);
    };

    const getTrend = () => {
        // Simulation de tendance
        const thisMonth = avoirs.filter(a => {
            const avoirDate = new Date(a.dateEmission);
            const now = new Date();
            return avoirDate.getMonth() === now.getMonth() && avoirDate.getFullYear() === now.getFullYear();
        }).length;
        
        const lastMonth = avoirs.filter(a => {
            const avoirDate = new Date(a.dateEmission);
            const lastMonthDate = new Date();
            lastMonthDate.setMonth(lastMonthDate.getMonth() - 1);
            return avoirDate.getMonth() === lastMonthDate.getMonth() && avoirDate.getFullYear() === lastMonthDate.getFullYear();
        }).length;
        
        if (thisMonth > lastMonth) return 'En hausse';
        if (thisMonth < lastMonth) return 'En baisse';
        return 'Stable';
    };

    const onInputChange = (e: React.ChangeEvent<HTMLInputElement | HTMLTextAreaElement>, name: string) => {
        const val = (e.target && e.target.value) || '';
        let _avoir = { ...avoir };
        (_avoir as any)[name] = val;
        setAvoir(_avoir);
    };

    const onNumberChange = (e: any, name: string) => {
        let _avoir = { ...avoir };
        (_avoir as any)[name] = e.value;
        setAvoir(_avoir);

        // Recalcul automatique du TTC
        if (name === 'montantHT' || name === 'tauxTVA') {
            const montantHT = name === 'montantHT' ? e.value : _avoir.montantHT;
            const tauxTVA = name === 'tauxTVA' ? e.value : _avoir.tauxTVA;
            _avoir.montantTTC = montantHT * (1 + tauxTVA / 100);
            setAvoir(_avoir);
        }
    };

    const onDropdownChange = (e: any, name: string) => {
        let _avoir = { ...avoir };
        (_avoir as any)[name] = e.value;
        setAvoir(_avoir);
    };

    const leftToolbarTemplate = () => {
        return (
            <div className="my-2 flex gap-2">
                <h5 className="m-0 flex align-items-center text-purple-600">
                    <i className="pi pi-minus-circle mr-2"></i>
                    Avoirs ({avoirs.length})
                </h5>
                <Chip 
                    label={`Montant total: ${formatCurrency(avoirs.reduce((sum, a) => sum + (a.montantTTC || 0), 0))}`} 
                    className="bg-purple-100 text-purple-800"
                />
                <Button 
                    label="Nouveau" 
                    icon="pi pi-plus" 
                    severity="success" 
                    size="small"
                    onClick={openNew}
                />
                <Button 
                    label="Rapport d'analyse" 
                    icon="pi pi-chart-pie" 
                    severity="help" 
                    size="small"
                    onClick={generateAvoirReport}
                />
            </div>
        );
    };

    const rightToolbarTemplate = () => {
        return (
            <Button 
                label="Exporter" 
                icon="pi pi-upload" 
                severity="help" 
                onClick={exportCSV} 
            />
        );
    };

    const actionBodyTemplate = (rowData: Facture) => {
        return (
            <div className="flex gap-1">
                <Button 
                    icon="pi pi-eye" 
                    rounded 
                    severity="info" 
                    size="small"
                    tooltip="Voir détails"
                    onClick={() => viewDetails(rowData)}
                />
                <Button 
                    icon="pi pi-print" 
                    rounded 
                    severity="help" 
                    size="small"
                    tooltip="Imprimer l'avoir"
                    onClick={() => {
                        toast.current?.show({
                            severity: 'info',
                            summary: 'Impression',
                            detail: `Impression de l'avoir ${rowData.numero}`,
                            life: 3000
                        });
                    }}
                />
                <Button 
                    icon="pi pi-send" 
                    rounded 
                    severity={"secondary" as any} 
                    size="small"
                    tooltip="Envoyer au client"
                    onClick={() => {
                        toast.current?.show({
                            severity: 'success',
                            summary: 'Envoi',
                            detail: `Avoir ${rowData.numero} envoyé au client`,
                            life: 3000
                        });
                    }}
                />
            </div>
        );
    };

    const statusBodyTemplate = (rowData: Facture) => {
        return (
            <div className="flex align-items-center gap-2">
                <Tag value="Avoir" severity="info" />
                <Tag
                    value={rowData.statut === StatutFacture.ENVOYEE ? 'Émis' : rowData.statut}
                    severity="success"
                />
            </div>
        );
    };

    const reasonBodyTemplate = (rowData: Facture) => {
        const reason = getAvoirReason(rowData.description || '');
        const label = getReasonLabel(reason);
        const severity = getAvoirSeverity(reason);
        
        return (
            <Tag 
                value={label} 
                severity={severity as any}
                className="text-xs"
            />
        );
    };

    const clientBodyTemplate = (rowData: Facture) => {
        if (!rowData.client) return '';
        return `${rowData.client.prenom} ${rowData.client.nom}`;
    };

    const header = (
        <div className="flex flex-column md:flex-row md:justify-content-between md:align-items-center">
            <h5 className="m-0">Avoirs - Gestion des remboursements</h5>
            <span className="block mt-2 md:mt-0 p-input-icon-left">
                <i className="pi pi-search" />
                <InputText 
                    type="search" 
                    placeholder="Rechercher..." 
                    onInput={(e) => setGlobalFilter(e.currentTarget.value)} 
                />
            </span>
        </div>
    );

    const avoirDialogFooter = (
        <>
            <Button label="Annuler" icon="pi pi-times" text onClick={hideDialog} />
            {isCreating && (
                <Button label="Créer l'avoir" icon="pi pi-check" text onClick={saveAvoir} />
            )}
        </>
    );

    return (
        <div className="grid">
            <div className="col-12">
                <Card>
                    <Toast ref={toast} />
                    <Toolbar className="mb-4" left={leftToolbarTemplate} right={rightToolbarTemplate} />

                    <DataTable
                        ref={dt}
                        value={avoirs}
                        selection={selectedAvoirs}
                        onSelectionChange={(e) => setSelectedAvoirs(e.value)}
                        selectionMode="multiple"
                        dataKey="id"
                        paginator
                        rows={10}
                        rowsPerPageOptions={[5, 10, 25]}
                        className="datatable-responsive"
                        paginatorTemplate="FirstPageLink PrevPageLink PageLinks NextPageLink LastPageLink CurrentPageReport RowsPerPageDropdown"
                        currentPageReportTemplate="Affichage de {first} à {last} sur {totalRecords} avoirs"
                        globalFilter={globalFilter}
                        emptyMessage="Aucun avoir trouvé."
                        header={header}
                        responsiveLayout="scroll"
                        loading={loading}
                        sortField="dateEmission"
                        sortOrder={-1}
                    >
                        <Column selectionMode="multiple" headerStyle={{ width: '4rem' }} />
                        <Column field="numero" header="Numéro" sortable headerStyle={{ minWidth: '10rem' }} />
                        <Column field="objet" header="Objet" sortable headerStyle={{ minWidth: '15rem' }} />
                        <Column field="client" header="Client" body={clientBodyTemplate} sortable headerStyle={{ minWidth: '12rem' }} />
                        <Column field="dateEmission" header="Date émission" body={(rowData) => formatDate(rowData.dateEmission)} sortable headerStyle={{ minWidth: '10rem' }} />
                        <Column field="reason" header="Motif" body={reasonBodyTemplate} headerStyle={{ minWidth: '12rem' }} />
                        <Column field="montantTTC" header="Montant TTC" body={(rowData) => formatCurrency(rowData.montantTTC)} sortable headerStyle={{ minWidth: '10rem' }} />
                        <Column field="statut" header="Statut" body={statusBodyTemplate} headerStyle={{ minWidth: '10rem' }} />
                        <Column body={actionBodyTemplate} headerStyle={{ minWidth: '12rem' }} />
                    </DataTable>

                    <Dialog 
                        visible={avoirDialog} 
                        style={{ width: '700px' }} 
                        header={isCreating ? "Créer un avoir" : "Détails de l'avoir"}
                        modal 
                        className="p-fluid" 
                        footer={avoirDialogFooter} 
                        onHide={hideDialog}
                    >
                        {isCreating ? (
                            <div className="formgrid grid">
                                <div className="field col-12">
                                    <label htmlFor="client">Client *</label>
                                    <Dropdown 
                                        id="client" 
                                        value={avoir.client} 
                                        options={clients} 
                                        onChange={(e) => onDropdownChange(e, 'client')} 
                                        placeholder="Sélectionnez un client"
                                        required 
                                        className={submitted && !avoir.client ? 'p-invalid' : ''} 
                                    />
                                    {submitted && !avoir.client && <small className="p-invalid">Le client est requis.</small>}
                                </div>

                                <div className="field col-12">
                                    <label htmlFor="objet">Objet *</label>
                                    <InputText 
                                        id="objet" 
                                        value={avoir.objet} 
                                        onChange={(e) => onInputChange(e, 'objet')} 
                                        required 
                                        className={submitted && !avoir.objet ? 'p-invalid' : ''} 
                                        placeholder="Objet de l'avoir"
                                    />
                                    {submitted && !avoir.objet && <small className="p-invalid">L'objet est requis.</small>}
                                </div>

                                <div className="field col-12">
                                    <label htmlFor="description">Description / Motif</label>
                                    <InputTextarea 
                                        id="description" 
                                        value={avoir.description} 
                                        onChange={(e) => onInputChange(e, 'description')} 
                                        rows={4} 
                                        placeholder="Décrivez la raison de l'avoir..."
                                    />
                                </div>

                                <div className="field col-12 md:col-4">
                                    <label htmlFor="montantHT">Montant HT (€) *</label>
                                    <InputNumber 
                                        id="montantHT" 
                                        value={avoir.montantHT} 
                                        onValueChange={(e) => onNumberChange(e, 'montantHT')} 
                                        mode="currency" 
                                        currency="EUR" 
                                        locale="fr-FR" 
                                        className={submitted && avoir.montantHT <= 0 ? 'p-invalid' : ''} 
                                    />
                                    {submitted && avoir.montantHT <= 0 && <small className="p-invalid">Le montant est requis.</small>}
                                </div>

                                <div className="field col-12 md:col-4">
                                    <label htmlFor="tauxTVA">Taux TVA (%)</label>
                                    <InputNumber 
                                        id="tauxTVA" 
                                        value={avoir.tauxTVA} 
                                        onValueChange={(e) => onNumberChange(e, 'tauxTVA')} 
                                        suffix="%" 
                                        min={0} 
                                        max={100} 
                                    />
                                </div>

                                <div className="field col-12 md:col-4">
                                    <label htmlFor="montantTTC">Montant TTC (€)</label>
                                    <InputNumber 
                                        id="montantTTC" 
                                        value={avoir.montantTTC} 
                                        mode="currency" 
                                        currency="EUR" 
                                        locale="fr-FR" 
                                        disabled
                                    />
                                </div>

                                <div className="field col-12">
                                    <label htmlFor="dateEmission">Date d'émission</label>
                                    <Calendar
                                        id="dateEmission"
                                        value={avoir.dateEmission ? new Date(avoir.dateEmission) : null}
                                        onChange={(e) => setAvoir(prev => ({ ...prev, dateEmission: (e.value as Date)?.toISOString() || new Date().toISOString() }))}
                                        dateFormat="dd/mm/yy"
                                        showIcon
                                    />
                                </div>
                            </div>
                        ) : selectedAvoir && (
                            <div className="formgrid grid">
                                <div className="field col-12">
                                    <h6>Informations de l'avoir</h6>
                                    <p><strong>Numéro:</strong> {selectedAvoir.numero}</p>
                                    <p><strong>Objet:</strong> {selectedAvoir.objet}</p>
                                    <p><strong>Client:</strong> {selectedAvoir.client ? `${selectedAvoir.client.prenom} ${selectedAvoir.client.nom}` : 'N/A'}</p>
                                    <p><strong>Date d'émission:</strong> {formatDate(selectedAvoir.dateEmission)}</p>
                                    <p><strong>Montant TTC:</strong> {formatCurrency(selectedAvoir.montantTTC || 0)}</p>
                                </div>

                                <Divider />

                                <div className="field col-12">
                                    <h6>Motif de l'avoir</h6>
                                    <div className="mb-2">
                                        <Tag 
                                            value={getReasonLabel(getAvoirReason(selectedAvoir.description || ''))} 
                                            severity={getAvoirSeverity(getAvoirReason(selectedAvoir.description || '')) as any}
                                        />
                                    </div>
                                    <p><strong>Description:</strong></p>
                                    <p className="text-700">{selectedAvoir.description || 'Aucune description'}</p>
                                </div>

                                <Divider />

                                <div className="field col-12">
                                    <h6>Actions disponibles</h6>
                                    <div className="flex gap-2">
                                        <Button 
                                            label="Imprimer" 
                                            icon="pi pi-print" 
                                            size="small"
                                            onClick={() => {
                                                toast.current?.show({
                                                    severity: 'info',
                                                    summary: 'Impression',
                                                    detail: `Impression de l'avoir ${selectedAvoir.numero}`,
                                                    life: 3000
                                                });
                                            }}
                                        />
                                        <Button 
                                            label="Envoyer" 
                                            icon="pi pi-send" 
                                            severity={"secondary" as any}
                                            size="small"
                                            onClick={() => {
                                                toast.current?.show({
                                                    severity: 'success',
                                                    summary: 'Envoi',
                                                    detail: `Avoir ${selectedAvoir.numero} envoyé au client`,
                                                    life: 3000
                                                });
                                            }}
                                        />
                                    </div>
                                </div>
                            </div>
                        )}
                    </Dialog>
                </Card>
            </div>
        </div>
    );
};

export default FacturesAvoirsPage;