const DEFAULT_CODE_LANGUAGE = 'plaintext'

const BASENAME_LANGUAGE_MAP: Record<string, string> = {
 dockerfile: 'dockerfile',
 '.dockerfile': 'dockerfile',
 '.npmrc': 'ini',
 '.babelrc': 'json',
 '.eslintrc': 'json',
 '.eslintignore': 'gitignore',
 '.prettierrc': 'json',
 '.gitignore': 'gitignore',
 '.dockerignore': 'gitignore',
 '.editorconfig': 'ini',
 '.htaccess': 'apacheconf',
 '.nginx': 'nginx'
}

const SUFFIX_LANGUAGE_MAP: Record<string, string> = {
 '.babel.config.js': 'json'
}

const EXTENSION_LANGUAGE_MAP: Record<string, string> = {
 '.js': 'javascript',
 '.jsx': 'javascript',
 '.ts': 'typescript',
 '.tsx': 'typescript',
 '.py': 'python',
 '.java': 'java',
 '.c': 'c',
 '.cpp': 'cpp',
 '.cc': 'cpp',
 '.cxx': 'cpp',
 '.h': 'c',
 '.hpp': 'cpp',
 '.hxx': 'cpp',
 '.hh': 'cpp',
 '.cs': 'csharp',
 '.go': 'go',
 '.rb': 'ruby',
 '.php': 'php',
 '.rs': 'rust',
 '.swift': 'swift',
 '.kt': 'kotlin',
 '.scala': 'scala',
 '.pl': 'perl',
 '.lua': 'lua',
 '.sh': 'shell',
 '.html': 'html',
 '.htm': 'html',
 '.css': 'css',
 '.dart': 'dart',
 '.r': 'r',
 '.m': 'matlab',
 '.sql': 'sql',
 '.json': 'json',
 '.yaml': 'yaml',
 '.yml': 'yaml',
 '.xml': 'xml',
 '.md': 'markdown',
 '.vue': 'vue',
 '.svelte': 'svelte',
 '.sass': 'scss',
 '.scss': 'scss',
 '.less': 'less',
 '.f90': 'fortran',
 '.f95': 'fortran',
 '.f03': 'fortran',
 '.jl': 'julia',
 '.ex': 'elixir',
 '.exs': 'elixir',
 '.elm': 'elm',
 '.clj': 'clojure',
 '.cljs': 'clojure',
 '.fs': 'fsharp',
 '.fsx': 'fsharp',
 '.hs': 'haskell',
 '.ml': 'ocaml',
 '.mli': 'ocaml',
 '.nim': 'nim',
 '.proto': 'protobuf',
 '.groovy': 'groovy',
 '.tf': 'terraform',
 '.tfvars': 'terraform',
 '.dockerfile': 'dockerfile',
 '.toml': 'toml',
 '.graphql': 'graphql',
 '.gql': 'graphql',
 '.astro': 'astro',
 '.zig': 'zig',
 '.v': 'v',
 '.ini': 'ini',
 '.env': 'dotenv',
 '.conf': 'configuration',
 '.config': 'configuration',
 '.properties': 'properties',
 '.lock': 'yaml'
}

const normalizeFilename = (filename: string): string => filename.replace(/\\/g, '/').toLowerCase()

const getBasename = (filename: string): string => {
 const normalized = normalizeFilename(filename)
 const parts = normalized.split('/')
 return parts[parts.length - 1] || normalized
}

const getExtension = (basename: string): string => {
 const dotIndex = basename.lastIndexOf('.')
 if (dotIndex === 0 && basename.indexOf('.', 1) === -1) {
 return basename
 }
 if (dotIndex > 0) {
 return basename.slice(dotIndex)
 }
 return ''
}

export const getLanguageFromFilename = (filename?: string): string => {
 if (!filename) return DEFAULT_CODE_LANGUAGE
 const basename = getBasename(filename)

 for (const [suffix, language] of Object.entries(SUFFIX_LANGUAGE_MAP)) {
 if (basename.endsWith(suffix)) {
 return language
 }
 }

 if (basename in BASENAME_LANGUAGE_MAP) {
 return BASENAME_LANGUAGE_MAP[basename]
 }

 const extension = getExtension(basename)
 return EXTENSION_LANGUAGE_MAP[extension] ?? DEFAULT_CODE_LANGUAGE
}

export { DEFAULT_CODE_LANGUAGE }