local api = vim.api
local ts = vim.treesitter

local parsers = require "nvim-treesitter.parsers"
local configs = require "nvim-treesitter.configs"

local M = {}

-- nvim-treesitter Highlight Group Mappings
-- Note: Some highlight groups may not be applied upstream, some may be experimental
-- TODO(clason): deprecated and will be removed for Nvim 0.8

local default_map = {
  ["annotation"] = "TSAnnotation",

  ["attribute"] = "TSAttribute",

  ["boolean"] = "TSBoolean",

  ["character"] = "TSCharacter",
  ["character.special"] = "TSCharacterSpecial",

  ["comment"] = "TSComment",

  ["conditional"] = "TSConditional",

  ["constant"] = "TSConstant",
  ["constant.builtin"] = "TSConstBuiltin",
  ["constant.macro"] = "TSConstMacro",

  ["constructor"] = "TSConstructor",

  ["debug"] = "TSDebug",
  ["define"] = "TSDefine",

  ["error"] = "TSError",
  ["exception"] = "TSException",

  ["field"] = "TSField",

  ["float"] = "TSFloat",

  ["function"] = "TSFunction",
  ["function.call"] = "TSFunctionCall",
  ["function.builtin"] = "TSFuncBuiltin",
  ["function.macro"] = "TSFuncMacro",

  ["include"] = "TSInclude",

  ["keyword"] = "TSKeyword",
  ["keyword.function"] = "TSKeywordFunction",
  ["keyword.operator"] = "TSKeywordOperator",
  ["keyword.return"] = "TSKeywordReturn",

  ["label"] = "TSLabel",

  ["method"] = "TSMethod",
  ["method.call"] = "TSMethodCall",

  ["namespace"] = "TSNamespace",

  ["none"] = "TSNone",
  ["number"] = "TSNumber",

  ["operator"] = "TSOperator",

  ["parameter"] = "TSParameter",
  ["parameter.reference"] = "TSParameterReference",

  ["preproc"] = "TSPreProc",

  ["property"] = "TSProperty",

  ["punctuation.delimiter"] = "TSPunctDelimiter",
  ["punctuation.bracket"] = "TSPunctBracket",
  ["punctuation.special"] = "TSPunctSpecial",

  ["repeat"] = "TSRepeat",

  ["storageclass"] = "TSStorageClass",

  ["string"] = "TSString",
  ["string.regex"] = "TSStringRegex",
  ["string.escape"] = "TSStringEscape",
  ["string.special"] = "TSStringSpecial",

  ["symbol"] = "TSSymbol",

  ["tag"] = "TSTag",
  ["tag.attribute"] = "TSTagAttribute",
  ["tag.delimiter"] = "TSTagDelimiter",

  ["text"] = "TSText",
  ["text.strong"] = "TSStrong",
  ["text.emphasis"] = "TSEmphasis",
  ["text.underline"] = "TSUnderline",
  ["text.strike"] = "TSStrike",
  ["text.title"] = "TSTitle",
  ["text.literal"] = "TSLiteral",
  ["text.uri"] = "TSURI",
  ["text.math"] = "TSMath",
  ["text.reference"] = "TSTextReference",
  ["text.environment"] = "TSEnvironment",
  ["text.environment.name"] = "TSEnvironmentName",

  ["text.note"] = "TSNote",
  ["text.warning"] = "TSWarning",
  ["text.danger"] = "TSDanger",

  ["todo"] = "TSTodo",

  ["type"] = "TSType",
  ["type.builtin"] = "TSTypeBuiltin",
  ["type.qualifier"] = "TSTypeQualifier",
  ["type.definition"] = "TSTypeDefinition",

  ["variable"] = "TSVariable",
  ["variable.builtin"] = "TSVariableBuiltin",
}

-- compatibility shim
local link_captures
if ts.highlighter.hl_map then
  link_captures = function(capture, hlgroup)
    ts.highlighter.hl_map[capture] = hlgroup
  end
elseif not vim.g.skip_ts_default_groups then
  link_captures = function(capture, hlgroup)
    api.nvim_set_hl(0, "@" .. capture, { link = hlgroup })
  end
end

local function link_all_captures()
  if link_captures then
    for capture, hlgroup in pairs(default_map) do
      link_captures(capture, hlgroup)
    end
  end
end

link_all_captures()

local function should_enable_vim_regex(config, lang)
  local additional_hl = config.additional_vim_regex_highlighting
  local is_table = type(additional_hl) == "table"

  return additional_hl and (not is_table or vim.tbl_contains(additional_hl, lang))
end

local function enable_syntax(bufnr)
  api.nvim_buf_set_option(bufnr, "syntax", "ON")
end

function M.stop(bufnr)
  if ts.highlighter.active[bufnr] then
    ts.highlighter.active[bufnr]:destroy()
  end
end

function M.start(bufnr, lang)
  local parser = parsers.get_parser(bufnr, lang)
  ts.highlighter.new(parser, {})
end

function M.attach(bufnr, lang)
  local config = configs.get_module "highlight"
  M.start(bufnr, lang)
  if should_enable_vim_regex(config, lang) then
    enable_syntax(bufnr)
  end
end

function M.detach(bufnr)
  M.stop(bufnr)
  enable_syntax(bufnr)
end

-- TODO(clason): remove obsolete function after bump to 0.8
function M.set_custom_captures(captures)
  for capture, hlgroup in pairs(captures) do
    link_captures(capture, hlgroup)
  end
end

function M.set_default_hlgroups()
  if not ts.highlighter.hl_map and not vim.g.skip_ts_default_groups then
    link_all_captures()
  end
  local highlights = {
    TSNone = { default = true },
    TSPunctDelimiter = { link = "Delimiter", default = true },
    TSPunctBracket = { link = "Delimiter", default = true },
    TSPunctSpecial = { link = "Delimiter", default = true },

    TSConstant = { link = "Constant", default = true },
    TSConstBuiltin = { link = "Special", default = true },
    TSConstMacro = { link = "Define", default = true },
    TSString = { link = "String", default = true },
    TSStringRegex = { link = "String", default = true },
    TSStringEscape = { link = "SpecialChar", default = true },
    TSStringSpecial = { link = "SpecialChar", default = true },
    TSCharacter = { link = "Character", default = true },
    TSCharacterSpecial = { link = "SpecialChar", default = true },
    TSNumber = { link = "Number", default = true },
    TSBoolean = { link = "Boolean", default = true },
    TSFloat = { link = "Float", default = true },

    TSFunction = { link = "Function", default = true },
    TSFunctionCall = { link = "TSFunction", default = true },
    TSFuncBuiltin = { link = "Special", default = true },
    TSFuncMacro = { link = "Macro", default = true },
    TSParameter = { link = "Identifier", default = true },
    TSParameterReference = { link = "TSParameter", default = true },
    TSMethod = { link = "Function", default = true },
    TSMethodCall = { link = "TSMethod", default = true },
    TSField = { link = "Identifier", default = true },
    TSProperty = { link = "Identifier", default = true },
    TSConstructor = { link = "Special", default = true },
    TSAnnotation = { link = "PreProc", default = true },
    TSAttribute = { link = "PreProc", default = true },
    TSNamespace = { link = "Include", default = true },
    TSSymbol = { link = "Identifier", default = true },

    TSConditional = { link = "Conditional", default = true },
    TSRepeat = { link = "Repeat", default = true },
    TSLabel = { link = "Label", default = true },
    TSOperator = { link = "Operator", default = true },
    TSKeyword = { link = "Keyword", default = true },
    TSKeywordFunction = { link = "Keyword", default = true },
    TSKeywordOperator = { link = "TSOperator", default = true },
    TSKeywordReturn = { link = "TSKeyword", default = true },
    TSException = { link = "Exception", default = true },
    TSDebug = { link = "Debug", default = true },
    TSDefine = { link = "Define", default = true },
    TSPreProc = { link = "PreProc", default = true },
    TSStorageClass = { link = "StorageClass", default = true },

    TSTodo = { link = "Todo", default = true },

    TSType = { link = "Type", default = true },
    TSTypeBuiltin = { link = "Type", default = true },
    TSTypeQualifier = { link = "Type", default = true },
    TSTypeDefinition = { link = "Typedef", default = true },

    TSInclude = { link = "Include", default = true },

    TSVariableBuiltin = { link = "Special", default = true },

    TSText = { link = "TSNone", default = true },
    TSStrong = { bold = true, default = true },
    TSEmphasis = { italic = true, default = true },
    TSUnderline = { underline = true },
    TSStrike = { strikethrough = true },

    TSMath = { link = "Special", default = true },
    TSTextReference = { link = "Constant", default = true },
    TSEnvironment = { link = "Macro", default = true },
    TSEnvironmentName = { link = "Type", default = true },
    TSTitle = { link = "Title", default = true },
    TSLiteral = { link = "String", default = true },
    TSURI = { link = "Underlined", default = true },

    TSComment = { link = "Comment", default = true },
    TSNote = { link = "SpecialComment", default = true },
    TSWarning = { link = "Todo", default = true },
    TSDanger = { link = "WarningMsg", default = true },

    TSTag = { link = "Label", default = true },
    TSTagDelimiter = { link = "Delimiter", default = true },
    TSTagAttribute = { link = "TSProperty", default = true },
  }

  for k, v in pairs(highlights) do
    api.nvim_set_hl(0, k, v)
  end
end

return M