import type { BaseLayer } from "./base-layer";
import type { Size } from "./geometry";

export const builtInTextFonts = ["Arial", "Georgia", "Courier New", "Trebuchet MS"] as const;
export type TextFontFamily = typeof builtInTextFonts[number];
export type TextAlignment = "left" | "center" | "right";
export type TextFontStyle = "normal" | "italic";
export type TextFontWeight = 400 | 700;

export type TextStyle = {
  fontFamily: TextFontFamily;
  fontSize: number;
  fontWeight: TextFontWeight;
  fontStyle: TextFontStyle;
  color: string;
  alignment: TextAlignment;
  lineHeight: number;
};

export type TextLayer = BaseLayer & {
  type: "text";
  content: string;
  style: TextStyle;
};

/** Deterministic layout box shared by selection, renderer and export. */
export function measureTextLayer(layer: Pick<TextLayer, "content" | "style">): Size {
  const lines = layer.content.split("\n");
  const weightFactor = layer.style.fontWeight === 700 ? 1.04 : 1;
  const italicFactor = layer.style.fontStyle === "italic" ? 1.03 : 1;
  const familyFactor = layer.style.fontFamily === "Courier New" ? 0.62 : layer.style.fontFamily === "Georgia" ? 0.56 : 0.54;
  const longest = Math.max(1, ...lines.map((line) => [...line].length));
  return {
    w: Math.max(1, longest * layer.style.fontSize * familyFactor * weightFactor * italicFactor),
    h: Math.max(1, lines.length * layer.style.fontSize * layer.style.lineHeight),
  };
}

export function isValidTextStyle(style: TextStyle): boolean {
  return builtInTextFonts.includes(style.fontFamily) && Number.isFinite(style.fontSize) && style.fontSize >= 1 && style.fontSize <= 1000
    && (style.fontWeight === 400 || style.fontWeight === 700) && (style.fontStyle === "normal" || style.fontStyle === "italic")
    && /^#[0-9a-f]{6}$/i.test(style.color) && (style.alignment === "left" || style.alignment === "center" || style.alignment === "right")
    && Number.isFinite(style.lineHeight) && style.lineHeight >= 0.5 && style.lineHeight <= 5;
}