import type { EventQrInviteLayout } from '../../api';

export const CANVAS_WIDTH = 1240;
export const CANVAS_HEIGHT = 1754;

export type LayoutElementType =
  | 'qr'
  | 'headline'
  | 'subtitle'
  | 'description'
  | 'link'
  | 'badge'
  | 'logo'
  | 'cta'
  | 'text';

export type LayoutTextAlign = 'left' | 'center' | 'right';

export interface LayoutElement {
  id: string;
  type: LayoutElementType;
  x: number;
  y: number;
  width: number;
  height: number;
  rotation?: number;
  fontSize?: number;
  align?: LayoutTextAlign;
  content?: string | null;
  fontFamily?: string | null;
  letterSpacing?: number;
  lineHeight?: number;
  fill?: string | null;
  locked?: boolean;
  initial?: boolean;
}

type PresetValue = number | ((context: LayoutPresetContext) => number);

type LayoutPresetElement = {
  id: string;
  type: LayoutElementType;
  x: PresetValue;
  y: PresetValue;
  width?: PresetValue;
  height?: PresetValue;
  fontSize?: number;
  align?: LayoutTextAlign;
  locked?: boolean;
  initial?: boolean;
};

type LayoutPreset = LayoutPresetElement[];

interface LayoutPresetContext {
  qrSize: number;
  canvasWidth: number;
  canvasHeight: number;
}

export interface LayoutElementPayload {
  id: string;
  type: LayoutElementType;
  x: number;
  y: number;
  width: number;
  height: number;
  rotation?: number;
  font_size?: number;
  align?: LayoutTextAlign;
  content?: string | null;
  font_family?: string | null;
  letter_spacing?: number;
  line_height?: number;
  fill?: string | null;
  locked?: boolean;
  initial?: boolean;
}

export interface LayoutSerializationContext {
  form: QrLayoutCustomization;
  eventName: string;
  inviteUrl: string;
  instructions: string[];
  qrSize: number;
  badgeFallback: string;
  logoUrl: string | null;
}

export type QrLayoutCustomization = {
  layout_id?: string;
  headline?: string;
  subtitle?: string;
  description?: string;
  badge_label?: string;
  instructions_heading?: string;
  instructions?: string[];
  link_heading?: string;
  link_label?: string;
  cta_label?: string;
  accent_color?: string;
  text_color?: string;
  background_color?: string;
  secondary_color?: string;
  badge_color?: string;
  background_gradient?: { angle?: number; stops?: string[] } | null;
  logo_data_url?: string | null;
  logo_url?: string | null;
  mode?: 'standard' | 'advanced';
  elements?: LayoutElementPayload[];
};

export const MIN_QR_SIZE = 240;
export const MAX_QR_SIZE = 720;
export const MIN_TEXT_WIDTH = 160;
export const MIN_TEXT_HEIGHT = 80;

export function clamp(value: number, min: number, max: number): number {
  if (Number.isNaN(value)) {
    return min;
  }
  return Math.min(Math.max(value, min), max);
}

export function clampElement(element: LayoutElement): LayoutElement {
  return {
    ...element,
    x: clamp(element.x, 0, CANVAS_WIDTH - element.width),
    y: clamp(element.y, 0, CANVAS_HEIGHT - element.height),
    width: clamp(element.width, 40, CANVAS_WIDTH),
    height: clamp(element.height, 40, CANVAS_HEIGHT),
  };
}

const DEFAULT_TYPE_STYLES: Record<LayoutElementType, { width: number; height: number; fontSize?: number; align?: LayoutTextAlign; locked?: boolean }> = {
  headline: { width: 620, height: 200, fontSize: 68, align: 'left' },
  subtitle: { width: 580, height: 140, fontSize: 34, align: 'left' },
  description: { width: 620, height: 280, fontSize: 28, align: 'left' },
  link: { width: 400, height: 110, fontSize: 28, align: 'center' },
  badge: { width: 280, height: 80, fontSize: 24, align: 'center' },
  logo: { width: 240, height: 180, align: 'center' },
  cta: { width: 400, height: 110, fontSize: 26, align: 'center' },
  qr: { width: 520, height: 520 },
  text: { width: 560, height: 200, fontSize: 26, align: 'left' },
};

const DEFAULT_PRESET: LayoutPreset = [
  { id: 'badge', type: 'badge', x: 120, y: 140, width: 320, height: 80, align: 'center', fontSize: 24 },
  { id: 'headline', type: 'headline', x: 120, y: 260, width: 620, height: 200, fontSize: 68, align: 'left' },
  { id: 'subtitle', type: 'subtitle', x: 120, y: 440, width: 600, height: 140, fontSize: 34, align: 'left' },
  { id: 'description', type: 'description', x: 120, y: 600, width: 620, height: 280, fontSize: 28, align: 'left' },
  {
    id: 'qr',
    type: 'qr',
    x: (context) => context.canvasWidth - context.qrSize - 140,
    y: 360,
    width: (context) => context.qrSize,
    height: (context) => context.qrSize,
  },
  {
    id: 'link',
    type: 'link',
    x: (context) => context.canvasWidth - 420,
    y: (context) => 400 + context.qrSize,
    width: 400,
    height: 110,
    fontSize: 28,
    align: 'center',
  },
  {
    id: 'cta',
    type: 'cta',
    x: (context) => context.canvasWidth - 420,
    y: (context) => 420 + context.qrSize + 140,
    width: 400,
    height: 110,
    fontSize: 26,
    align: 'center',
  },
];
const evergreenVowsPreset: LayoutPreset = [
  { id: 'logo', type: 'logo', x: 120, y: 140, width: 240, height: 180 },
  { id: 'badge', type: 'badge', x: 400, y: 160, width: 320, height: 80, align: 'center', fontSize: 24 },
  { id: 'headline', type: 'headline', x: 120, y: 360, width: 620, height: 220, fontSize: 70, align: 'left' },
  { id: 'subtitle', type: 'subtitle', x: 120, y: 560, width: 600, height: 140, fontSize: 34, align: 'left' },
  { id: 'description', type: 'description', x: 120, y: 720, width: 620, height: 280, fontSize: 28, align: 'left' },
  {
    id: 'qr',
    type: 'qr',
    x: (context) => context.canvasWidth - context.qrSize - 160,
    y: 460,
    width: (context) => context.qrSize,
    height: (context) => context.qrSize,
  },
  {
    id: 'link',
    type: 'link',
    x: (context) => context.canvasWidth - 420,
    y: (context) => 500 + context.qrSize,
    width: 400,
    height: 110,
    align: 'center',
  },
  {
    id: 'cta',
    type: 'cta',
    x: (context) => context.canvasWidth - 420,
    y: (context) => 520 + context.qrSize + 150,
    width: 400,
    height: 110,
    align: 'center',
  },
];

const midnightGalaPreset: LayoutPreset = [
  { id: 'badge', type: 'badge', x: 360, y: 160, width: 520, height: 90, align: 'center', fontSize: 26 },
  { id: 'headline', type: 'headline', x: 220, y: 300, width: 800, height: 220, fontSize: 76, align: 'center' },
  { id: 'subtitle', type: 'subtitle', x: 260, y: 520, width: 720, height: 140, fontSize: 36, align: 'center' },
  {
    id: 'qr',
    type: 'qr',
    x: (context) => (context.canvasWidth - context.qrSize) / 2,
    y: 700,
    width: (context) => context.qrSize,
    height: (context) => context.qrSize,
  },
  {
    id: 'link',
    type: 'link',
    x: (context) => (context.canvasWidth - 420) / 2,
    y: (context) => 740 + context.qrSize,
    width: 420,
    height: 120,
    align: 'center',
  },
  {
    id: 'cta',
    type: 'cta',
    x: (context) => (context.canvasWidth - 420) / 2,
    y: (context) => 770 + context.qrSize + 150,
    width: 420,
    height: 120,
    align: 'center',
  },
  { id: 'description', type: 'description', x: 200, y: 1040, width: 840, height: 260, fontSize: 28, align: 'center' },
];

const gardenBrunchPreset: LayoutPreset = [
  { id: 'badge', type: 'badge', x: 160, y: 160, width: 360, height: 80, align: 'center', fontSize: 24 },
  { id: 'headline', type: 'headline', x: 160, y: 300, width: 560, height: 200, fontSize: 66, align: 'left' },
  { id: 'description', type: 'description', x: 160, y: 520, width: 560, height: 260, fontSize: 28, align: 'left' },
  {
    id: 'qr',
    type: 'qr',
    x: 160,
    y: 840,
    width: (context) => Math.min(context.qrSize, 520),
    height: (context) => Math.min(context.qrSize, 520),
  },
  {
    id: 'link',
    type: 'link',
    x: 160,
    y: (context) => 880 + Math.min(context.qrSize, 520),
    width: 420,
    height: 110,
    align: 'center',
  },
  {
    id: 'cta',
    type: 'cta',
    x: 160,
    y: (context) => 910 + Math.min(context.qrSize, 520) + 140,
    width: 420,
    height: 110,
    align: 'center',
  },
  { id: 'subtitle', type: 'subtitle', x: 780, y: 320, width: 320, height: 140, fontSize: 32, align: 'left' },
  { id: 'text-strip', type: 'text', x: 780, y: 480, width: 320, height: 320, fontSize: 24, align: 'left' },
];

const sparklerSoireePreset: LayoutPreset = [
  { id: 'badge', type: 'badge', x: 360, y: 150, width: 520, height: 90, align: 'center', fontSize: 26 },
  { id: 'headline', type: 'headline', x: 200, y: 300, width: 840, height: 220, fontSize: 72, align: 'center' },
  { id: 'subtitle', type: 'subtitle', x: 260, y: 520, width: 720, height: 140, fontSize: 34, align: 'center' },
  { id: 'description', type: 'description', x: 220, y: 680, width: 800, height: 240, fontSize: 28, align: 'center' },
  {
    id: 'qr',
    type: 'qr',
    x: (context) => (context.canvasWidth - context.qrSize) / 2,
    y: 960,
    width: (context) => context.qrSize,
    height: (context) => context.qrSize,
  },
  {
    id: 'link',
    type: 'link',
    x: (context) => (context.canvasWidth - 420) / 2,
    y: (context) => 1000 + context.qrSize,
    width: 420,
    height: 110,
    align: 'center',
  },
  {
    id: 'cta',
    type: 'cta',
    x: (context) => (context.canvasWidth - 420) / 2,
    y: (context) => 1030 + context.qrSize + 140,
    width: 420,
    height: 110,
    align: 'center',
  },
];

const confettiBashPreset: LayoutPreset = [
  { id: 'badge', type: 'badge', x: 140, y: 180, width: 360, height: 90, align: 'center', fontSize: 24 },
  { id: 'headline', type: 'headline', x: 140, y: 320, width: 520, height: 220, fontSize: 68, align: 'left' },
  { id: 'subtitle', type: 'subtitle', x: 140, y: 520, width: 520, height: 140, fontSize: 34, align: 'left' },
  { id: 'description', type: 'description', x: 140, y: 680, width: 520, height: 240, fontSize: 26, align: 'left' },
  {
    id: 'qr',
    type: 'qr',
    x: (context) => context.canvasWidth - context.qrSize - 200,
    y: 360,
    width: (context) => context.qrSize,
    height: (context) => context.qrSize,
  },
  {
    id: 'link',
    type: 'link',
    x: (context) => context.canvasWidth - 420,
    y: (context) => 400 + context.qrSize,
    width: 400,
    height: 110,
    align: 'center',
  },
  {
    id: 'cta',
    type: 'cta',
    x: (context) => context.canvasWidth - 420,
    y: (context) => 430 + context.qrSize + 140,
    width: 400,
    height: 110,
    align: 'center',
  },
  { id: 'text-strip', type: 'text', x: 140, y: 960, width: 860, height: 220, fontSize: 26, align: 'left' },
];

const LAYOUT_PRESETS: Record<string, LayoutPreset> = {
  'default': DEFAULT_PRESET,
  'evergreen-vows': evergreenVowsPreset,
  'midnight-gala': midnightGalaPreset,
  'garden-brunch': gardenBrunchPreset,
  'sparkler-soiree': sparklerSoireePreset,
  'confetti-bash': confettiBashPreset,
};

function resolvePresetValue(value: PresetValue | undefined, context: LayoutPresetContext, fallback: number): number {
  if (typeof value === 'function') {
    const resolved = value(context);
    return typeof resolved === 'number' ? resolved : fallback;
  }
  if (typeof value === 'number') {
    return value;
  }
  return fallback;
}

export function buildDefaultElements(
  layout: EventQrInviteLayout,
  form: QrLayoutCustomization,
  eventName: string,
  qrSize: number
): LayoutElement[] {
  const size = clamp(qrSize, MIN_QR_SIZE, MAX_QR_SIZE);
  const context: LayoutPresetContext = {
    qrSize: size,
    canvasWidth: CANVAS_WIDTH,
    canvasHeight: CANVAS_HEIGHT,
  };

  const preset = LAYOUT_PRESETS[layout.id ?? ''] ?? DEFAULT_PRESET;

  const instructionsHeading = form.instructions_heading ?? layout.instructions_heading ?? "So funktioniert's";
  const instructionsList = Array.isArray(form.instructions) && form.instructions.length
    ? form.instructions
    : (layout.instructions ?? []);

  const baseContent: Record<string, string | null> = {
    headline: form.headline ?? eventName,
    subtitle: form.subtitle ?? layout.subtitle ?? '',
    description: form.description ?? layout.description ?? '',
    badge: form.badge_label ?? layout.badge_label ?? 'Digitale Gästebox',
    link: form.link_label ?? '',
    cta: form.cta_label ?? layout.cta_label ?? 'Scan mich & starte direkt',
    instructions_heading: instructionsHeading,
    instructions_text: instructionsList[0] ?? null,
  };

  const elements = preset.map((config) => {
    const typeStyle = DEFAULT_TYPE_STYLES[config.type] ?? { width: 420, height: 160 };
    const widthFallback = config.type === 'qr' ? size : typeStyle.width;
    const heightFallback = config.type === 'qr' ? size : typeStyle.height;
    const element: LayoutElement = {
      id: config.id,
      type: config.type,
      x: resolvePresetValue(config.x, context, 0),
      y: resolvePresetValue(config.y, context, 0),
      width: resolvePresetValue(config.width, context, widthFallback),
      height: resolvePresetValue(config.height, context, heightFallback),
      fontSize: config.fontSize ?? typeStyle.fontSize,
      align: config.align ?? typeStyle.align ?? 'left',
      content: null,
      locked: config.locked ?? typeStyle.locked ?? false,
      initial: config.initial ?? true,
    };

    if (config.type === 'description') {
      element.lineHeight = 1.4;
    }

    switch (config.id) {
      case 'headline':
        element.content = baseContent.headline;
        break;
      case 'subtitle':
        element.content = baseContent.subtitle;
        break;
      case 'description':
        element.content = baseContent.description;
        break;
      case 'badge':
        element.content = baseContent.badge;
        break;
      case 'link':
        element.content = baseContent.link;
        break;
      case 'cta':
        element.content = baseContent.cta;
        break;
      case 'text-strip':
        element.content = instructionsList.join('\n').trim() || layout.description || 'Nutze diesen Bereich für zusätzliche Hinweise oder Storytelling.';
        break;
      case 'logo':
        element.content = form.logo_data_url ?? form.logo_url ?? layout.logo_url ?? null;
        break;
      default:
        if (config.type === 'text') {
          element.content = element.content ?? 'Individualisiere diesen Textblock mit eigenen Infos.';
        }
        break;
    }

    if (config.type === 'qr') {
      element.locked = false;
    }

    const clamped = clampElement(element);
    return {
      ...clamped,
      initial: element.initial ?? true,
    };
  });

  return elements;
}

export function payloadToElements(payload?: LayoutElementPayload[] | null): LayoutElement[] {
  if (!Array.isArray(payload)) {
    return [];
  }

  return payload.map((entry) =>
    clampElement({
      id: entry.id,
      type: entry.type,
      x: Number(entry.x ?? 0),
      y: Number(entry.y ?? 0),
      width: Number(entry.width ?? 100),
      height: Number(entry.height ?? 100),
      rotation: typeof entry.rotation === 'number' ? entry.rotation : 0,
      fontSize: typeof entry.font_size === 'number' ? entry.font_size : undefined,
      align: entry.align ?? 'left',
      content: entry.content ?? null,
      fontFamily: entry.font_family ?? null,
      letterSpacing: entry.letter_spacing ?? undefined,
      lineHeight: entry.line_height ?? undefined,
      fill: entry.fill ?? null,
      locked: Boolean(entry.locked),
      initial: Boolean(entry.initial),
    })
  );
}

export function elementsToPayload(elements: LayoutElement[]): LayoutElementPayload[] {
  return elements.map((element) => ({
    id: element.id,
    type: element.type,
    x: element.x,
    y: element.y,
    width: element.width,
    height: element.height,
    rotation: element.rotation ?? 0,
    font_size: element.fontSize,
    align: element.align,
    content: element.content ?? null,
    font_family: element.fontFamily ?? null,
    letter_spacing: element.letterSpacing,
    line_height: element.lineHeight,
    fill: element.fill ?? null,
    locked: element.locked ?? false,
    initial: element.initial ?? false,
  }));
}

export function normalizeElements(elements: LayoutElement[]): LayoutElement[] {
  const seen = new Set<string>();
  return elements
    .filter((element) => {
      if (!element.id) {
        return false;
      }
      if (seen.has(element.id)) {
        return false;
      }
      seen.add(element.id);
      return true;
    })
    .map(clampElement);
}