/**
 * Felddefinitionen und Helfer für den Datenexport.
 *
 * Lagen bis v1.118.1 in `app/api/user/export/route.ts`. Next.js erlaubt in einer route.ts
 * nur Route-Handler als Exporte — alles andere lässt die generierte Typprüfung auflaufen
 * ("does not satisfy the constraint"). Ausserdem importierte SettingsSidebar EXPORT_FIELDS
 * aus der Route und zog damit einen Server-Handler in den Client-Graphen.
 *
 * Diese Datei bleibt bewusst frei von Server-only-Importen (prisma, next-auth) — sie wird
 * von SettingsSidebar (Client-Komponente) importiert, und jeder Top-Level-Import hier landet
 * sonst im Client-Bundle ("PrismaClient is unable to run in this browser environment"),
 * selbst wenn nur EXPORT_FIELDS gebraucht wird. Das DB-lesende fetchExportData liegt darum
 * in export-data-server.ts.
 */

// ── Field registry ─────────────────────────────────────────────────────────

export type ExportFieldKey =
    | 'week'
    | 'weekGoal'
    | 'completedDate'
    | 'scheduledDate'
    | 'createdDate'
    | 'project'
    | 'list'
    | 'priority'
    | 'url'
    | 'notes'
    | 'description'
    | 'delegatedTo'
    | 'delegationNote'
    | 'startTime'
    | 'kanbanStage';

export const EXPORT_FIELDS: {
    key: ExportFieldKey;
    labelDe: string;
    labelEn: string;
    defaultOn: boolean;
    csvOnly?: boolean; // not a table column, only used as a section in PDF/CSV
}[] = [
    { key: 'week',           labelDe: 'Kalenderwoche',      labelEn: 'Calendar week',    defaultOn: true,  csvOnly: true },
    { key: 'weekGoal',       labelDe: 'Wochenziel',         labelEn: 'Goal of the week', defaultOn: true,  csvOnly: true },
    { key: 'completedDate',  labelDe: 'Erledigt am',        labelEn: 'Completed',        defaultOn: true  },
    { key: 'scheduledDate',  labelDe: 'Geplant für',        labelEn: 'Scheduled for',    defaultOn: true  },
    { key: 'createdDate',    labelDe: 'Erstellt am',        labelEn: 'Created',          defaultOn: false },
    { key: 'project',        labelDe: 'Projekt',            labelEn: 'Project',          defaultOn: true  },
    { key: 'list',           labelDe: 'Liste',              labelEn: 'List',             defaultOn: true  },
    { key: 'priority',       labelDe: 'Priorität',          labelEn: 'Priority',         defaultOn: true  },
    { key: 'url',            labelDe: 'Link / URL',         labelEn: 'Link / URL',       defaultOn: false },
    { key: 'notes',          labelDe: 'Notiz',              labelEn: 'Notes',            defaultOn: false },
    { key: 'description',    labelDe: 'Beschreibung',       labelEn: 'Description',      defaultOn: false },
    { key: 'delegatedTo',    labelDe: 'Delegiert an',       labelEn: 'Delegated to',     defaultOn: false },
    { key: 'delegationNote', labelDe: 'Delegationsnotiz',   labelEn: 'Delegation note',  defaultOn: false },
    { key: 'startTime',      labelDe: 'Uhrzeit',            labelEn: 'Start time',       defaultOn: false },
    { key: 'kanbanStage',    labelDe: 'Kanban-Stage',       labelEn: 'Kanban stage',     defaultOn: false },
];

// ── Shared helpers (also used by export-pdf route) ─────────────────────────

export function isoWeek(date: Date): string {
    const d = new Date(Date.UTC(date.getFullYear(), date.getMonth(), date.getDate()));
    const dayNum = d.getUTCDay() || 7;
    d.setUTCDate(d.getUTCDate() + 4 - dayNum);
    const yearStart = new Date(Date.UTC(d.getUTCFullYear(), 0, 1));
    const weekNo = Math.ceil((((d.getTime() - yearStart.getTime()) / 86400000) + 1) / 7);
    return `${d.getUTCFullYear()}-W${String(weekNo).padStart(2, '0')}`;
}

export function weekMondaySunday(weekKey: string): { mon: Date; sun: Date } {
    const [year, w] = weekKey.split('-W');
    const d = new Date(Date.UTC(parseInt(year), 0, 1));
    d.setUTCDate(d.getUTCDate() + (parseInt(w) - 1) * 7 - (d.getUTCDay() || 7) + 1);
    const sun = new Date(d); sun.setUTCDate(d.getUTCDate() + 6);
    return { mon: d, sun };
}

export function weekLabel(weekKey: string, de: boolean): string {
    const [, w] = weekKey.split('-W');
    const year = weekKey.split('-W')[0];
    const { mon, sun } = weekMondaySunday(weekKey);
    const fmt = (x: Date) => x.toLocaleDateString(de ? 'de-DE' : 'en-GB', { day: '2-digit', month: 'short', timeZone: 'UTC' });
    return de
        ? `KW ${w} — ${year}  (${fmt(mon)} – ${fmt(sun)})`
        : `Week ${w} — ${year}  (${fmt(mon)} – ${fmt(sun)})`;
}

export function fmtDate(d: Date | null | undefined, de: boolean): string {
    if (!d) return '';
    return de
        ? d.toLocaleDateString('de-DE', { day: '2-digit', month: '2-digit', year: 'numeric' })
        : d.toLocaleDateString('en-GB', { day: '2-digit', month: 'short', year: 'numeric' });
}

export function priorityLabel(task: any, de: boolean): string {
    if (task.urgency != null && task.importance != null) {
        if (task.urgency && task.importance)  return de ? 'Sofort erledigen' : 'Do now';
        if (!task.urgency && task.importance) return de ? 'Planen'           : 'Schedule';
        if (task.urgency && !task.importance) return de ? 'Delegieren'       : 'Delegate';
        return de ? 'Eliminieren' : 'Eliminate';
    }
    if (task.priority) return task.priority;
    return '';
}

export function priorityColor(task: any): string {
    if (task.urgency != null && task.importance != null) {
        if (task.urgency && task.importance)  return '#ef4444';
        if (!task.urgency && task.importance) return '#3b82f6';
        if (task.urgency && !task.importance) return '#f97316';
        return '#9ca3af';
    }
    const map: Record<string, string> = { A: '#ef4444', B: '#f97316', C: '#eab308', D: '#3b82f6', E: '#9ca3af' };
    return task.priority ? (map[task.priority] || '#6b7280') : '#6b7280';
}

export function csvCell(value: string): string {
    return `"${(value ?? '').replace(/"/g, '""').replace(/\n/g, ' ')}"`;
}

// ── CSV route ──────────────────────────────────────────────────────────────