# Run `npm run watch:textmate-yaml` while working on this file.
# roughly based on this grammar:
# ```ebnf
# JSONSelection        ::= PathSelection | NamedSelection*
# SubSelection         ::= "{" NamedSelection* "}"
# NamedSelection       ::= (Alias | "...")? PathSelection | Alias SubSelection
# Alias                ::= Key ":"
# Path                 ::= VarPath | KeyPath | AtPath | ExprPath
# PathSelection        ::= Path SubSelection?
# VarPath              ::= "$" (NO_SPACE Identifier)? PathTail
# KeyPath              ::= Key NonEmptyPathTail
# AtPath               ::= "@" PathTail
# ExprPath             ::= "$(" LitExpr ")" PathTail
# PathTail             ::= "?"? (PathStep "?"?)*
# NonEmptyPathTail     ::= "?"? (PathStep "?"?)+
# PathStep             ::= "." Key | "->" Identifier MethodArgs?
# Key                  ::= Identifier | LitString
# Identifier           ::= [a-zA-Z_] NO_SPACE [0-9a-zA-Z_]*
# MethodArgs           ::= "(" (LitExpr ("," LitExpr)* ","?)? ")"
# LitExpr              ::= LitPath | LitOpChain | LitPrimitive | LitObject | LitArray | PathSelection
# LitPath              ::= (LitPrimitive | LitObject | LitArray) NonEmptyPathTail
# LitOpChain           ::= LitExpr LitOp LitExpr
# LitPrimitive         ::= LitString | LitNumber | "true" | "false" | "null"
# LitString            ::= "'" ("\\'" | [^'])* "'" | '"' ('\\"' | [^"])* '"'
# LitNumber            ::= "-"? ([0-9]+ ("." [0-9]*)? | "." [0-9]+)
# LitObject            ::= "{" (LitProperty ("," LitProperty)* ","?)? "}"
# LitProperty          ::= Key ":" LitExpr
# LitArray             ::= "[" (LitExpr ("," LitExpr)* ","?)? "]"
# LitOp                ::= "??" | "?!" | "&&" | "||" | "==" | "!=" | "<" | "<=" | ">" | ">=" | +" | "-" | "*" | "/" | "%"
# NO_SPACE             ::= !SpacesOrComments
# SpacesOrComments     ::= (Spaces | Comment)+
# Spaces               ::= ("⎵" | "\t" | "\r" | "\n")+
# Comment              ::= "#" [^\n]*
# ```
$schema: https://raw.githubusercontent.com/martinring/tmlanguage/master/tmlanguage.json
name: "Apollo Connectors Mapping Syntax"
scopeName: "source.apollo.connectors.mapping"
patterns:
  - include: "#JSONSelection"
  - include: "#Comment"
  - include: "source.graphql#graphql-skip-newlines"
# can be referenced from `begin`, `end` or `match` properties like `{{identifier}}` or `{{key}}`
# within those fields, it's also possible to reference evaluated earlier patterns like `{{#PathSelection.begin}}`
variables:
  identifier: "[a-zA-Z_][0-9a-zA-Z_]*"
  # prettier-ignore
  string: "\"[^\"]*\"|'[^']*'"
  key: "{{identifier}}|{{string}}"
  operator: "[?][?]|[?][!]|&&|[|][|]|==|!=|<|<=|(?<!-)>|(?<!-)>=|[+]|-(?!>)|[*]|/|%"
  operatorCharacter: "[?!&|=<>*/%+-]"
  alias: "{{key}}\\s*:"
  varPathMatch: "[$]"
  keyPathMatch: "({{key}})(?={{pathTailMatch}})"
  pathStepMatch: "[.]{{key}}|->{{identifier}}"
  pathTailMatch: "\\s*(?:[?])?(?=\\s*{{pathStepMatch}})"
  atPathMatch: "@"
  exprPathMatch: "$[(]"
  notEscaped: "(?<![\\\\])(?:[\\\\]{2})*"
  builtinMethod: "echo|map|eq|match|first|last|slice|size|entries|or|and|jsonStringify|joinNotNull|filter|gte|lte|ne|gt|lt"
  reservedMethod: "typeof|matchIf|match_if|add|sub|mul|div|mod|has|get|keys|values|not"
# can be referenced from `name` properties or other styles like `{{.identifier}}` or `{{.key}}`
styles:
  alias: "variable.other.property.alias"
  alias_colon: "{{.colon}}" # just an example - we can reference other styles here
  colon: "punctuation.colon.alias"
  field: "variable.graphql"
  property: "variable.other.property"
  method: "support.function"
  builtinMethod: "support.function.builtin"
  arrow: "keyword.operator.arrow"
  comma: "punctuation.separator.comma"
  brace_open: "punctuation.brace.open" #{
  brace_close: "punctuation.brace.close" #}
  paren_open: "punctuation.paren.open" #(
  paren_close: "punctuation.paren.close" #)
  bracket_open: "punctuation.bracket.open" #[
  bracket_close: "punctuation.bracket.close" #]
  optional_chain: "variable.question.mark"
  expr_dollar: "variable.other.constant"
  var_dollar: "variable.other.constant"
  at: "variable.other.constant"
  spread: "keyword.operator.spread"
  dot: "variable.dot"
  operator: "keyword.operator"
  fixedPrimitive: "constant.language"
  string: "string.quoted.graphql"
  string_single: "string.quoted.single.graphql"
  string_double: "string.quoted.double.graphql"
  string_open: "punctuation.definition.string.begin.graphql"
  string_close: "punctuation.definition.string.end.graphql"
  number: "constant.numeric"
  comment: "comment.line.connectors.mapping"
  comment_leading_ws: "punctuation.whitespace.comment.leading.connectors.mapping"

repository:
  # JSONSelection        ::= PathSelection | NamedSelection*
  JSONSelection:
    patterns:
      - include: "#NamedSelection"
      - include: "#PathSelection"
      - include: "#Comment"
  # SubSelection         ::= "{" NamedSelection* "}"
  SubSelection:
    begin: "\\s*({)"
    beginCaptures:
      "1":
        name: "{{.brace_open}}"
    end: "\\s*(})"
    endCaptures:
      "1":
        name: "{{.brace_close}}"
    patterns:
      - include: "#NamedSelection"
      - include: "#Comment"
  # NamedSelection       ::= (Alias | "...")? PathSelection | Alias SubSelection
  # Alias                ::= Key ":"
  # Path                 ::= VarPath | KeyPath | AtPath | ExprPath
  # PathSelection        ::= Path SubSelection?
  PathSelection:
    begin: "(?={{varPathMatch}}|{{keyPathMatch}}|{{atPathMatch}}|{{exprPathMatch}})"
    end: "(?=.)"
    applyEndPatternLast: 1
    patterns:
      - include: "#ExprPath" # needs higher priority that `VarPath`
      - include: "#VarPath"
      - include: "#KeyPath"
      - include: "#AtPath"
  NamedSelection:
    patterns:
      - begin: "({{key}})\\s*(:)\\s*{{#PathSelection.begin}}"
        beginCaptures:
          "1":
            name: "{{.alias}}"
          "2":
            name: "{{.alias_colon}}"
        end: "(?=.)"
        applyEndPatternLast: 1
        patterns:
          - include: "#PathSelection"
      - begin: "([.][.][.])\\s*{{#PathSelection.begin}}"
        beginCaptures:
          "1":
            name: "{{.spread}}"
        end: "(?=.)"
        applyEndPatternLast: 1
        patterns:
          - include: "#PathSelection"
      - include: "#PathSelection"
      - begin: "({{key}})\\s*(:)\\s*(?={{#SubSelection.begin}})"
        beginCaptures:
          "1":
            name: "{{.alias}}"
          "2":
            name: "{{.alias_colon}}"
        end: "(?=.)"
        applyEndPatternLast: 1
        patterns:
          - include: "#SubSelection"
      # added back even though it's not part of the current spec: NamedFieldSelection
      - include: "#NamedFieldSelection"
  # temporarily added back
  # NamedFieldSelection  ::= Alias? Key SubSelection?
  NamedFieldSelection:
    begin: "(?:({{key}})\\s*(:)\\s*)?({{key}})"
    beginCaptures:
      "1":
        name: "{{.alias}}"
      "2":
        name: "{{.alias_colon}}"
      "3":
        name: "{{.field}}"
    end: "(?=.)"
    applyEndPatternLast: 1
    patterns:
      - include: "#SubSelection"
  # VarPath              ::= "$" (NO_SPACE Identifier)? PathTail
  VarPath:
    begin: "([$])({{identifier}})?(?!\\w)"
    beginCaptures:
      "1":
        name: "{{.var_dollar}}"
      "2":
        name: "{{.field}}"
    end: "(?=.)"
    applyEndPatternLast: 1
    patterns:
      - include: "#PathTail"
  # KeyPath              ::= Key NonEmptyPathTail
  KeyPath:
    begin: "({{key}})(?={{pathTailMatch}})"
    beginCaptures:
      "1":
        name: "{{.field}}"
    end: "(?=.)"
    applyEndPatternLast: 1
    patterns:
      # "nonEmpty" part already covered through `(?={{pathTailMatch}})` in `begin`
      #- include: "#NonEmptyPathTail"
      - include: "#PathTail"
  # AtPath               ::= "@" PathTail
  AtPath:
    begin: "(@)"
    beginCaptures:
      "1":
        name: "{{.at}}"
    end: "(?=.)"
    applyEndPatternLast: 1
    patterns:
      - include: "#PathTail"
  # ExprPath             ::= "$(" LitExpr ")" PathTail
  ExprPath:
    begin: "([$])(?=[(])"
    beginCaptures:
      "1":
        name: "{{.expr_dollar}}"
    end: "(?=.)"
    applyEndPatternLast: 1
    patterns:
      - begin: "([(])"
        beginCaptures:
          "1":
            name: "{{.paren_open}}"
        end: "([)])"
        endCaptures:
          "1":
            name: "{{.paren_close}}"
        patterns:
          - include: "#LitExpr"
      - include: "#PathStep"
  # PathTail             ::= "?"? (PathStep "?"?)*
  # optional chaining moved into `PathStep` later
  PathTail:
    begin: "([?])?(?=\\s*{{pathStepMatch}})"
    beginCaptures:
      "1":
        name: "{{.optional_chain}}"
    end: "(?=.)"
    applyEndPatternLast: 1
    patterns:
      - include: "#PathStep"
  # NonEmptyPathTail     ::= "?"? (PathStep "?"?)+
  # PathStep             ::= "." Key | "->" Identifier MethodArgs?
  # changed to and added optional chaining that would usually live in `PathTail`|`NonEmptyPathTail`:
  # PathStepDotAccess    ::= "." Key "?"?
  # PathStepArrowMethodArgs ::= "->" Identifier MethodArgs "?"?
  # PathStepArrowAccess  ::= "->" Identifier "?"?
  # PathStep             ::= PathStepDotAccess | PathStepArrowMethodArgs | PathStepArrowAccess
  PathStepDotAccess:
    match: "([.])({{key}})([?]?)"
    captures:
      "1":
        name: "{{.dot}}"
      "2":
        name: "{{.field}}"
      "3":
        name: "{{.optional_chain}}"
  PathStepArrowMethodArgs:
    begin: "(->)(({{builtinMethod}})|{{identifier}})([(])"
    end: "([)])([?]?)"
    applyEndPatternLast: 1
    beginCaptures:
      "1":
        name: "{{.arrow}}"
      "2":
        name: "{{.method}}"
      "3":
        name: "{{.builtinMethod}}"
      "4":
        name: "{{.brace_open}}"
    endCaptures:
      "1":
        name: "{{.brace_close}}"
      "2":
        name: "{{.optional_chain}}"
    patterns:
      - include: "#LitExpr"
      - match: ","
        name: "{{.comma}}"
  PathStepArrowAccess:
    match: "(->)({{identifier}})([?]?)"
    captures:
      "1":
        name: "{{.arrow}}"
      "2":
        name: "{{.field}}"
      "3":
        name: "{{.optional_chain}}"
  PathStep:
    patterns:
      - include: "#PathStepDotAccess"
      - include: "#PathStepArrowMethodArgs"
      - include: "#PathStepArrowAccess"
  # Key (in variables)                 ::= Identifier | LitString
  # Identifier (in variables)          ::= [a-zA-Z_] NO_SPACE [0-9a-zA-Z_]*
  # MethodArgs (inlined into PathStepArrowMethodArgs)            ::= "(" (LitExpr ("," LitExpr)* ","?)? ")"
  # LitExpr              ::= LitPath | LitOpChain | LitPrimitive | LitObject | LitArray | PathSelection
  LitExpr:
    patterns:
      # - include: "#LitOpChain"
      - include: "#LitOpChainCenter"
      # - include: "#LitPath"
      - include: "#LitPathTail"
      - include: "#LitPrimitive"
      - include: "#LitObject"
      - include: "#LitArray"
      - include: "#PathSelection"
      - include: "#Comment"
  # LitPath              ::= (LitPrimitive | LitObject | LitArray) NonEmptyPathTail
  # changed to
  # LitPathTail              ::= NonEmptyPathTail
  # but ensures that it's not the first `LitExpr` by doing a negative lookbehind for `(`, which would indicate we're the first entry in a `ExprPath`.
  LitPathTail:
    begin: "(?<![(])(?={{pathTailMatch}})"
    end: "(?=.)"
    applyEndPatternLast: 1
    patterns:
      # "nonEmpty" part already covered through `(?={{pathTailMatch}})` in `begin`
      #- include: "#NonEmptyPathTail"
      - include: "#PathTail"
  # LitOpChain           ::= LitExpr LitOp LitExpr
  # changed to
  # LitOpChainCenter          ::= LitOp
  # as `MethodArgs` might match `LitExpr` more than once anyways.
  # Does lookarounds to ensure that it's in the middle of an expression, i.e. not at the start or end.
  LitOpChainCenter:
    match: "(?<![(]|{{operatorCharacter}})({{operator}})(?!\\s*(?:{{operatorCharacter}}|[)]))"
    captures:
      "1":
        name: "{{.operator}}"
  # LitPrimitive         ::= LitString | LitNumber | "true" | "false" | "null"
  LitPrimitive:
    patterns:
      - include: "#LitString"
      - include: "#LitNumber"
      - match: "\\b(true|false|null)\\b"
        name: "{{.fixedPrimitive}}"
  # LitString            ::= "'" ("\\'" | [^'])* "'" | '"' ('\\"' | [^"])* '"'
  LitString:
    # prettier-ignore
    begin: "((\")|('))"
    end: "{{notEscaped}}(?=\\1)((\")|('))"
    contentName: "{{.string}}"
    beginCaptures:
      "1":
        name: "{{.string_open}}"
      "2":
        name: "{{.string_double}}"
      "3":
        name: "{{.string_single}}"
    endCaptures:
      "1":
        name: "{{.string_close}}"
      "2":
        name: "{{.string_double}}"
      "3":
        name: "{{.string_single}}"

  # LitNumber            ::= "-"? ([0-9]+ ("." [0-9]*)? | "." [0-9]+)
  LitNumber:
    name: "{{.number}}"
    match: "(-?)([0-9]+([.][0-9]*)?|[.][0-9]+)"
  # LitObject            ::= "{" (LitProperty ("," LitProperty)* ","?)? "}"
  LitObject:
    begin: "\\s*({)"
    beginCaptures:
      "1":
        name: "{{.brace_open}}"
    end: "\\s*(})"
    endCaptures:
      "1":
        name: "{{.brace_close}}"
    patterns:
      - include: "#LitProperty"
      - match: ","
        name: "{{.comma}}"
      - include: "#Comment"
  # LitProperty          ::= Key ":" LitExpr
  LitProperty:
    begin: "\\b({{identifier}})\\s*(:)\\s*"
    beginCaptures:
      "1":
        name: "{{.property}}"
      "2":
        name: "{{.colon}}"
    end: "(?=.)"
    applyEndPatternLast: 1
    patterns:
      - include: "#LitExpr"
  # LitArray             ::= "[" (LitExpr ("," LitExpr)* ","?)? "]"
  LitArray:
    begin: "\\s*(\\[)"
    beginCaptures:
      "1":
        name: "{{.bracket_open}}"
    end: "\\s*(\\])"
    endCaptures:
      "1":
        name: "{{.bracket_close}}"
    patterns:
      - include: "#LitExpr"
      - match: ","
        name: "{{.comma}}"
  # LitOp                ::= "??" | "?!" | "&&" | "||" | "==" | "!=" | "<" | "<=" | ">" | ">=" | +" | "-" | "*" | "/" | "%"
  # inlined into `LitOpChainCenter`
  # NO_SPACE             ::= !SpacesOrComments
  # SpacesOrComments     ::= (Spaces | Comment)+
  # Spaces               ::= ("⎵" | "\t" | "\r" | "\n")+
  # Comment              ::= "#" [^\n]*
  Comment:
    match: "(\\s*)(#.*?)$"
    captures:
      "1":
        name: "{{.comment_leading_ws}}"
      "2":
        name: "{{.comment}}"

  # additional rules used for strings, e.g. in `POST: "/foo/bar/{$id}"`
  JSONSelectionString:
    contentName: string.quoted
    begin: '(")'
    beginCaptures:
      "1":
        name: "string.quoted.double.graphql {{.string_open}}"
    end: '(")'
    endCaptures:
      "1":
        name: "string.quoted.double.graphql {{.string_close}}"
    patterns:
      - begin: "\\s*({)"
        beginCaptures:
          "1":
            name: "punctuation.section.embedded {{.brace_open}}"
        end: "\\s*(})"
        endCaptures:
          "1":
            name: "punctuation.section.embedded {{.brace_close}}"
        contentName: meta.embedded.string.connectors.mapping.selectionstring.graphql
        debugName: "embedded"
        patterns:
          - include: "#PathSelection"