import type { Plugin } from "vite";
import fs from "fs";
import path from "path";

interface TokenTheme {
  [key: string]: any;
  breakpoint?: Record<string, string>;
}

interface TokenConfig {
  theme: TokenTheme;
  fonts?: Record<
    string,
    {
      "font-family": string;
      "font-weight": string | number;
      "font-style": string;
      src: string;
    }
  >;
  utilities?: Record<string, Record<string, any>>;
  components?: Record<string, Record<string, unknown>>;
}

function generateCssVariableName(path: string[]): string {
  return `--${path.join("-")}`;
}

function isObject(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}

function generateMediaQuery(breakpoint: string, styles: string): string {
  return `@media (min-width: ${breakpoint}) {\n    ${styles}\n  }`;
}

function processThemeValue(
  path: string[],
  value: unknown,
  breakpoints: Record<string, string>
): string[] {
  const cssRules: string[] = [];
  let varName = generateCssVariableName(path);

  // Special handling for colors
  if (path[0] === "color") {
    if (path.length === 2) {
      varName = `--${path.join("-")}`;
    } else if (isObject(value) && !("default" in value)) {
      // For nested color objects, use the existing path (will be handled in the object case)
      varName = `--${path.join("-")}`;
    }
  }

  if (typeof value === "string" || typeof value === "number") {
    cssRules.push(`${varName}: ${value};`);
  } else if (isObject(value)) {
    if ("default" in value) {
      cssRules.push(`${varName}: ${value.default};`);

      Object.entries(value).forEach(([key, val]) => {
        if (key !== "default" && breakpoints[key]) {
          cssRules.push(generateMediaQuery(breakpoints[key], `${varName}: ${val};`));
        }
      });
    } else {
      Object.entries(value).forEach(([key, val]) => {
        cssRules.push(...processThemeValue([...path, key], val, breakpoints));
      });
    }
  }

  return cssRules;
}

function generateThemeVariables(theme: TokenTheme): string {
  const breakpoints = theme.breakpoint || {};
  const rootRules: string[] = [];

  Object.entries(theme).forEach(([key, value]) => {
    if (key !== "breakpoint") {
      rootRules.push(...processThemeValue([key], value, breakpoints));
    }
  });

  return `:root {\n  ${rootRules.join("\n  ")}\n}`;
}

function generateThemeSection(theme: TokenTheme, fonts?: TokenConfig["fonts"]): string {
  const variables = Object.entries(theme)
    .filter(([key]) => key !== "breakpoint")
    .map(([key, value]) => {
      if (key === "color") {
        const colorVars: string[] = [];
        Object.entries(value).forEach(([colorName, colorValue]) => {
          if (typeof colorValue === "string") {
            colorVars.push(`--color-${colorName}: var(--color-${colorName});`);
          } else if (isObject(colorValue)) {
            Object.keys(colorValue).forEach((shade) => {
              colorVars.push(`--color-${colorName}-${shade}: var(--color-${colorName}-${shade});`);
            });
          }
        });
        return colorVars.join("\n  ");
      }

      if (isObject(value)) {
        return Object.keys(value)
          .map((subKey) => `--${key}-${subKey}: var(--${key}-${subKey});`)
          .join("\n  ");
      }
      return `--${key}: var(--${key});`;
    })
    .join("\n  ");

  const breakpoints = Object.entries(theme.breakpoint || {})
    .map(([key, value]) => `--breakpoint-${key}: ${value};`)
    .join("\n  ");

  const fontVariables = fonts
    ? Object.entries(fonts)
        .map(([key, font]) => `--font-${key}: "${font["font-family"]}";`)
        .join("\n  ")
    : "";

  return `@theme {\n  --*: initial;\n  ${breakpoints}\n  ${fontVariables}\n  ${variables}\n}`;
}

function generateFontFaces(fonts: NonNullable<TokenConfig["fonts"]>): string {
  return Object.entries(fonts)
    .map(([_, font]) => {
      return `@font-face {\n  font-family: "${font["font-family"]}";\n  font-weight: ${font["font-weight"]};\n  font-style: ${font["font-style"]};\n  src: ${font["src"]};\n}`;
    })
    .join("\n\n");
}

function generateComponents(
  components: NonNullable<TokenConfig["components"]>,
  breakpoints: Record<string, string>
): string {
  const processComponentStyles = (
    baseSelector: string,
    styles: Record<string, unknown>
  ): string[] => {
    const cssRules: string[] = [];

    Object.entries(styles).forEach(([selector, value]) => {
      if (isObject(value)) {
        const rules: string[] = [];

        Object.entries(value).forEach(([prop, propValue]) => {
          if (isObject(propValue) && "default" in propValue) {
            // Handle responsive properties
            rules.push(`    ${prop}: ${propValue.default};`);

            Object.entries(propValue).forEach(([bp, val]) => {
              if (bp !== "default" && breakpoints[bp]) {
                rules.push(`    @media (min-width: ${breakpoints[bp]}) {`);
                rules.push(`      ${prop}: ${val};`);
                rules.push(`    }`);
              }
            });
          } else {
            // Handle regular properties
            rules.push(`    ${prop}: ${propValue};`);
          }
        });

        cssRules.push(`  ${baseSelector}-${selector} {`);
        cssRules.push(rules.join("\n"));
        cssRules.push(`  }`);
      }
    });

    return cssRules;
  };

  const componentRules = Object.entries(components)
    .map(([selector, styles]) => {
      if (isObject(styles)) {
        const processedStyles = processComponentStyles(selector, styles);
        return processedStyles.join("\n");
      }
      return "";
    })
    .filter(Boolean)
    .join("\n\n");

  return `@layer components {\n${componentRules}\n}`;
}

function generateUtilities(
  utilities: NonNullable<TokenConfig["utilities"]>,
  breakpoints: Record<string, string>
): string {
  const processUtilityStyles = (selector: string, styles: Record<string, unknown>): string[] => {
    const cssRules: string[] = [];

    Object.entries(styles).forEach(([prop, value]) => {
      if (isObject(value) && "default" in value) {
        cssRules.push(`  ${prop}: ${value.default};`);

        Object.entries(value).forEach(([bp, val]) => {
          if (bp !== "default" && breakpoints[bp]) {
            cssRules.push(`  @media (min-width: ${breakpoints[bp]}) {`);
            cssRules.push(`    ${prop}: ${val};`);
            cssRules.push(`  }`);
          }
        });
      } else if (typeof value === "string" || typeof value === "number") {
        cssRules.push(`  ${prop}: ${value};`);
      }
    });

    return [`@utility ${selector} {`, ...cssRules, `}`];
  };

  return Object.entries(utilities)
    .map(([selector, styles]) => {
      if (isObject(styles)) {
        return processUtilityStyles(selector, styles).join("\n");
      }
      return "";
    })
    .filter(Boolean)
    .join("\n\n");
}

export default function tokensToTw(
  tokenUrl: string = "assets/css/tokens.json",
  outputUrl: string = "assets/css/tokens.css"
): Plugin {
  const tokenPath = path.resolve(tokenUrl);
  const outputPath = path.resolve(outputUrl);

  return {
    name: "tokens-to-tw",
    async buildStart() {
      await generateCSS();
    },
    async hotUpdate({ file, server }) {
      if (file.endsWith("tokens.json")) {
        await generateCSS();
      }
    },
  };

  async function generateCSS() {
    try {
      const tokenContent = await fs.promises.readFile(tokenPath, "utf-8");
      const tokens = JSON.parse(tokenContent) as TokenConfig;

      const cssContent = [
        generateThemeVariables(tokens.theme),
        tokens.fonts ? generateFontFaces(tokens.fonts) : "",
        generateThemeSection(tokens.theme, tokens.fonts),
        tokens.components
          ? generateComponents(tokens.components, tokens.theme.breakpoint || {})
          : "",
        tokens.utilities ? generateUtilities(tokens.utilities, tokens.theme.breakpoint || {}) : "",
        // v-lay from gds-style :')
        `@utility lay {
  display: grid;
  grid-auto-flow: initial;
  grid-auto-columns: minmax(0, 1fr);
  grid-auto-rows: minmax(0, auto);
}
@utility lay-v {
  grid-auto-flow: row;
}
@utility lay-h {
    grid-auto-flow: column;
  }
@utility lay-o {
  &>* {
    grid-area: 1 / 1;
  }
}
@utility lay-fluid {
  grid-auto-columns: initial;
  grid-auto-rows: initial;
  justify-content: flex-start;
}`,
      ]
        .filter(Boolean)
        .join("\n\n");

      await fs.promises.writeFile(outputPath, cssContent);
    } catch (error) {
      console.error("Error generating CSS:", error);
    }
  }
}