import {parser as cshParser} from "./csh-parser.js"
import {
  LRLanguage,
  indentNodeProp,
  foldNodeProp,
  foldInside,
  delimitedIndent,
  continuedIndent
} from "@codemirror/language"
import {styleTags, tags as t} from "@lezer/highlight"
import {completeFromList, CompletionSource} from "@codemirror/autocomplete"

/// A language provider for the C shell, based on the Lezer grammar in
/// `csh.grammar`.
export const cshLanguage = LRLanguage.define({
  name: "csh",
  parser: cshParser.configure({
    props: [
      indentNodeProp.add({
        Group: delimitedIndent({closing: "}"}),
        Subshell: delimitedIndent({closing: ")"}),
        WhileStatement: delimitedIndent({closing: "end"}),
        ForeachStatement: delimitedIndent({closing: "end"}),
        SwitchStatement: delimitedIndent({closing: "endsw"}),
        // `then` sits on the same line as the `if` it belongs to, so what is
        // indented is everything after that line.
        IfStatement: continuedIndent({except: /^\s*(endif|else)\b/}),
        CaseClause: continuedIndent({except: /^\s*(case|default|endsw)\b/})
      }),
      foldNodeProp.add({
        Group: foldInside,
        Subshell: foldInside,
        WhileStatement: foldInside,
        ForeachStatement: foldInside,
        SwitchStatement: foldInside
      }),
      styleTags({
        "if then else endif": t.controlKeyword,
        "while foreach end repeat": t.controlKeyword,
        "switch case default endsw": t.controlKeyword,
        "set setenv unset alias": t.definitionKeyword,
        Label: t.labelName,

        Comment: t.lineComment,
        String: t.string,
        RawString: t.string,
        HeredocBody: t.special(t.string),
        Escape: t.escape,
        LineContinuation: t.escape,
        Glob: t.special(t.string),

        "SimpleCommand/CommandName ShortCommand/CommandName": t.function(t.variableName),
        VariableName: t.definition(t.variableName),

        SimpleExpansion: t.variableName,
        ParamName: t.variableName,
        ParamOp: t.operator,
        Dollar: t.variableName,
        // `:q` and its relatives say what to do with the word before them,
        // which is what an operator is.
        Modifier: t.operator,
        Number: t.number,

        RedirectOp: t.controlOperator,
        "PipeOp Background": t.controlOperator,
        "AndOp OrOp NotOp": t.logicOperator,

        "AddOp MulOp": t.arithmeticOperator,
        "ShiftOp BitAndOp BitXorOp BitOrOp BitNotOp": t.bitwiseOperator,
        "RelateOp EqualOp MatchOp": t.compareOperator,
        FileTestOp: t.operatorKeyword,
        AssignOp: t.definitionOperator,
        IncDecOp: t.updateOperator,
        // `@` is a command rather than a symbol, and reads as the arithmetic
        // it introduces.
        "@": t.definitionKeyword,

        '"\\""': t.string,
        '"${" "}" "{"': t.brace,
        '"(" ")"': t.paren,
        '"[" "]"': t.squareBracket,
        '";"': t.separator,
        Terminator: t.separator
      })
    ]
  }),
  languageData: {
    commentTokens: {line: "#"},
    closeBrackets: {brackets: ["(", "[", "{", "'", '"', "`"]},
    indentOnInput: /^\s*(endif|end|endsw|else|breaksw|\}|\))$/
  }
})

// csh has no functions, so its builtins are the whole of what it can be told
// to do on its own, and there are few enough to name.
const builtins = [
  "alias", "bg", "break", "breaksw", "case", "cd", "chdir", "continue",
  "default", "dirs", "echo", "else", "end", "endif", "endsw", "eval", "exec",
  "exit", "fg", "foreach", "glob", "goto", "hashstat", "history", "if", "jobs",
  "kill", "limit", "login", "logout", "nice", "nohup", "notify", "onintr",
  "popd", "pushd", "rehash", "repeat", "set", "setenv", "shift", "source",
  "stop", "suspend", "switch", "then", "time", "umask", "unalias", "unhash",
  "unlimit", "unset", "unsetenv", "wait", "while", "@"
].map(label => ({label, type: "keyword"}))

// The variables csh sets for you. `status` is where the last command's exit
// code lands, which is `$?` everywhere else.
const specials = [
  "argv", "cdpath", "cwd", "echo", "histchars", "history", "home", "ignoreeof",
  "mail", "noclobber", "noglob", "nonomatch", "notify", "path", "prompt",
  "savehist", "shell", "status", "term", "time", "user", "verbose"
].map(label => ({label, type: "constant"}))

/// Autocompletion for the C shell's builtins and the variables it sets.
export const cshCompletion: CompletionSource = completeFromList([...builtins, ...specials])

export {cshParser}