import {
  fileBasename,
  formatFilePathPosition,
  inlineCodeFilePathCandidate,
  normalizeMarkdownLinkDestination,
  parseMarkdownFileLink,
} from "@t3tools/client-runtime/markdown-links";
import { videoMimeType } from "@t3tools/shared/video";

import type { MARKDOWN_FILE_ICON_SOURCES } from "./markdownFileIcons.generated";

const POSITION_SUFFIX_PATTERN = /:\d+(?::\d+)?$/;

export type MarkdownLinkPresentation =
  | {
      readonly kind: "external";
      readonly href: string;
      readonly host: string;
    }
  | {
      readonly kind: "file";
      readonly href: string;
      readonly icon: MarkdownFileIcon;
      readonly label: string;
      readonly path: string;
      readonly line?: number;
      readonly column?: number;
    }
  | {
      readonly kind: "link";
      readonly href: string | null;
    };

export type MarkdownFileIcon = keyof typeof MARKDOWN_FILE_ICON_SOURCES;

export type MarkdownLinkIcon = "github";

/**
 * Sites whose brand mark replaces the generic external-link glyph. The marks
 * are monochrome and tinted with the link color, so they follow the theme.
 */
export function resolveMarkdownLinkIcon(host: string): MarkdownLinkIcon | null {
  const hostname = host.toLowerCase();
  if (hostname === "github.com" || hostname.endsWith(".github.com")) return "github";
  return null;
}

const FILE_ICON_BY_NAME: Readonly<Record<string, MarkdownFileIcon>> = {
  ".babelrc": "babel",
  ".babelrc.json": "babel",
  ".bash_profile": "bash",
  ".bashrc": "bash",
  ".browserslistrc": "browserslist",
  ".dockerignore": "docker",
  ".eslintignore": "eslint",
  ".eslintrc": "eslint",
  ".eslintrc.cjs": "eslint",
  ".eslintrc.js": "eslint",
  ".eslintrc.json": "eslint",
  ".eslintrc.yaml": "eslint",
  ".eslintrc.yml": "eslint",
  ".gitattributes": "git",
  ".gitignore": "git",
  ".gitkeep": "git",
  ".gitmodules": "git",
  ".oxlintrc.json": "oxc",
  ".postcssrc": "postcss",
  ".postcssrc.json": "postcss",
  ".postcssrc.yaml": "postcss",
  ".postcssrc.yml": "postcss",
  ".prettierignore": "prettier",
  ".prettierrc": "prettier",
  ".prettierrc.json": "prettier",
  ".prettierrc.cjs": "prettier",
  ".prettierrc.js": "prettier",
  ".prettierrc.mjs": "prettier",
  ".prettierrc.toml": "prettier",
  ".prettierrc.yaml": "prettier",
  ".prettierrc.yml": "prettier",
  ".stylelintignore": "stylelint",
  ".stylelintrc": "stylelint",
  ".stylelintrc.cjs": "stylelint",
  ".stylelintrc.js": "stylelint",
  ".stylelintrc.json": "stylelint",
  ".stylelintrc.mjs": "stylelint",
  ".stylelintrc.yaml": "stylelint",
  ".stylelintrc.yml": "stylelint",
  ".terraform.lock.hcl": "terraform",
  ".zprofile": "bash",
  ".zshenv": "bash",
  ".zshrc": "bash",
  "agents.md": "agents",
  "babel.config.js": "babel",
  "babel.config.cjs": "babel",
  "babel.config.json": "babel",
  "babel.config.mjs": "babel",
  "biome.json": "biome",
  "biome.jsonc": "biome",
  "bun.lock": "bun",
  "bun.lockb": "bun",
  "bunfig.toml": "bun",
  "claude.md": "claude",
  "compose.yaml": "docker",
  "compose.yml": "docker",
  "docker-compose.yaml": "docker",
  "docker-compose.yml": "docker",
  "docker-compose.override.yml": "docker",
  dockerfile: "docker",
  "eslint.config.js": "eslint",
  "eslint.config.cjs": "eslint",
  "eslint.config.mjs": "eslint",
  "eslint.config.mts": "eslint",
  "eslint.config.ts": "eslint",
  gemfile: "ruby",
  "next.config.js": "nextjs",
  "next.config.mjs": "nextjs",
  "next.config.mts": "nextjs",
  "next.config.ts": "nextjs",
  "package.json": "package",
  "pnpm-lock.yaml": "pnpm",
  "pnpm-workspace.yaml": "pnpm",
  "postcss.config.js": "postcss",
  "postcss.config.cjs": "postcss",
  "postcss.config.mjs": "postcss",
  "postcss.config.ts": "postcss",
  "prettier.config.js": "prettier",
  "prettier.config.cjs": "prettier",
  "prettier.config.mjs": "prettier",
  rakefile: "ruby",
  "readme.md": "readme",
  "stylelint.config.js": "stylelint",
  "stylelint.config.cjs": "stylelint",
  "stylelint.config.mjs": "stylelint",
  "svgo.config.js": "svgo",
  "svgo.config.cjs": "svgo",
  "svgo.config.mjs": "svgo",
  "svgo.config.ts": "svgo",
  "tailwind.config.js": "tailwind",
  "tailwind.config.cjs": "tailwind",
  "tailwind.config.mjs": "tailwind",
  "tailwind.config.ts": "tailwind",
  "tsconfig.json": "tsconfig",
  "vite.config.js": "vite",
  "vite.config.mjs": "vite",
  "vite.config.mts": "vite",
  "vite.config.ts": "vite",
  "webpack.config.js": "webpack",
  "webpack.config.babel.js": "webpack",
  "webpack.config.cjs": "webpack",
  "webpack.config.mjs": "webpack",
  "webpack.config.ts": "webpack",
};

const FILE_ICON_BY_EXTENSION: Readonly<Record<string, MarkdownFileIcon>> = {
  "7z": "zip",
  astro: "astro",
  avif: "image",
  "code-workspace": "vscode",
  bash: "bash",
  bmp: "image",
  bz2: "zip",
  c: "c",
  cc: "cpp",
  cpp: "cpp",
  cxx: "cpp",
  css: "css",
  csv: "table",
  cts: "typescript",
  db: "database",
  env: "text",
  "env.development": "text",
  "env.local": "text",
  "env.production": "text",
  eot: "font",
  erb: "ruby",
  fish: "bash",
  gif: "image",
  go: "go",
  gql: "graphql",
  graphql: "graphql",
  gz: "zip",
  h: "c",
  hh: "cpp",
  hpp: "cpp",
  hxx: "cpp",
  htm: "html",
  html: "html",
  ico: "image",
  icns: "image",
  ini: "text",
  inl: "cpp",
  jar: "zip",
  jpeg: "image",
  jpg: "image",
  js: "javascript",
  jsx: "react",
  json: "json",
  jsonc: "json",
  less: "css",
  md: "markdown",
  mdx: "markdown",
  "mdx.tsx": "markdown",
  mjs: "javascript",
  mts: "typescript",
  png: "image",
  postcss: "css",
  py: "python",
  pyi: "python",
  pyw: "python",
  pyx: "python",
  rake: "ruby",
  rar: "zip",
  rb: "ruby",
  rs: "rust",
  sass: "sass",
  scss: "sass",
  sh: "bash",
  sql: "database",
  sqlite: "database",
  sqlite3: "database",
  svelte: "svelte",
  svg: "svg",
  swift: "swift",
  tar: "zip",
  tf: "terraform",
  tfstate: "terraform",
  tfvars: "terraform",
  tgz: "zip",
  ts: "typescript",
  tsv: "table",
  tsx: "react",
  txt: "text",
  woff: "font",
  woff2: "font",
  vue: "vue",
  wasm: "wasm",
  webp: "image",
  yml: "yml",
  yaml: "yml",
  zig: "zig",
  zip: "zip",
  zsh: "bash",
};

/** Native link and media APIs have no document scheme to inherit from protocol-relative URLs. */
export function normalizeNativeMarkdownUrl(value: string): string {
  return value.startsWith("//") ? `https:${value}` : value;
}

export function resolveMarkdownFileIcon(value: string): MarkdownFileIcon {
  const basename = fileBasename(value).replace(POSITION_SUFFIX_PATTERN, "").toLowerCase();
  if (videoMimeType({ name: basename, mimeType: "" }) !== null) return "video";
  const exactIcon = FILE_ICON_BY_NAME[basename];
  if (exactIcon) return exactIcon;
  if (basename.startsWith("tsconfig.") && basename.endsWith(".json")) {
    return "tsconfig";
  }
  const segments = basename.split(".");
  for (let index = 1; index < segments.length; index += 1) {
    const icon = FILE_ICON_BY_EXTENSION[segments.slice(index).join(".")];
    if (icon) return icon;
  }
  return "default";
}

export function resolveMarkdownLinkPresentation(href: string): MarkdownLinkPresentation {
  const normalized = normalizeMarkdownLinkDestination(href);
  try {
    const parsed = new URL(normalizeNativeMarkdownUrl(normalized));
    if (parsed.protocol === "http:" || parsed.protocol === "https:") {
      return {
        kind: "external",
        href: parsed.toString(),
        host: parsed.hostname,
      };
    }
  } catch {
    // Relative paths and non-URL link destinations are handled below.
  }

  const target = parseMarkdownFileLink(normalized);
  if (target) {
    return {
      kind: "file",
      href: normalized,
      icon: resolveMarkdownFileIcon(target.path),
      label: fileBasename(formatFilePathPosition(target)),
      path: target.path,
      ...(target.line ? { line: target.line } : {}),
      ...(target.column ? { column: target.column } : {}),
    };
  }

  return {
    kind: "link",
    href: /^(?:mailto|tel):/i.test(normalized) ? normalized : null,
  };
}

/** Backticks become file references only when the shared path heuristic recognizes the whole span. */
export function resolveMarkdownInlineCodePresentation(
  content: string,
): Extract<MarkdownLinkPresentation, { readonly kind: "file" }> | null {
  const candidate = inlineCodeFilePathCandidate(content);
  if (candidate === null) return null;
  const presentation = resolveMarkdownLinkPresentation(candidate);
  return presentation.kind === "file" ? presentation : null;
}