local api = vim.api
local fn = vim.fn
local luv = vim.loop

local utils = require "nvim-treesitter.utils"
local parsers = require "nvim-treesitter.parsers"
local info = require "nvim-treesitter.info"
local configs = require "nvim-treesitter.configs"
local shell = require "nvim-treesitter.shell_command_selectors"

local M = {}

---@class LockfileInfo
---@field revision string

---@type table<string, LockfileInfo>
local lockfile = {}

M.compilers = { vim.fn.getenv "CC", "cc", "gcc", "clang", "cl", "zig" }
M.prefer_git = fn.has "win32" == 1
M.command_extra_args = {}
M.ts_generate_args = nil

local started_commands = 0
local finished_commands = 0
local failed_commands = 0
local complete_std_output = {}
local complete_error_output = {}

local function reset_progress_counter()
  if started_commands ~= finished_commands then
    return
  end
  started_commands = 0
  finished_commands = 0
  failed_commands = 0
  complete_std_output = {}
  complete_error_output = {}
end

local function get_job_status()
  return "[nvim-treesitter] ["
    .. finished_commands
    .. "/"
    .. started_commands
    .. (failed_commands > 0 and ", failed: " .. failed_commands or "")
    .. "]"
end

---@param lang string
---@return function
local function reattach_if_possible_fn(lang, error_on_fail)
  return function()
    for _, buf in ipairs(vim.api.nvim_list_bufs()) do
      if parsers.get_buf_lang(buf) == lang then
        vim._ts_remove_language(lang)
        local ok, err
        if vim.treesitter.language.add then
          local ft = vim.bo[buf].filetype
          ok, err = pcall(vim.treesitter.language.add, lang, { filetype = ft })
        else
          ok, err = pcall(vim.treesitter.language.require_language, lang)
        end
        if not ok and error_on_fail then
          vim.notify("Could not load parser for " .. lang .. ": " .. vim.inspect(err))
        end
        for _, mod in ipairs(require("nvim-treesitter.configs").available_modules()) do
          if ok then
            require("nvim-treesitter.configs").reattach_module(mod, buf, lang)
          else
            require("nvim-treesitter.configs").detach_module(mod, buf)
          end
        end
      end
    end
  end
end

---@param lang string
---@param validate boolean|nil
---@return InstallInfo
local function get_parser_install_info(lang, validate)
  local parser_config = parsers.get_parser_configs()[lang]

  if not parser_config then
    error('Parser not available for language "' .. lang .. '"')
  end

  local install_info = parser_config.install_info

  if validate then
    vim.validate {
      url = { install_info.url, "string" },
      files = { install_info.files, "table" },
    }
  end

  return install_info
end

local function load_lockfile()
  local filename = utils.join_path(utils.get_package_path(), "lockfile.json")
  lockfile = vim.fn.filereadable(filename) == 1 and vim.fn.json_decode(vim.fn.readfile(filename)) or {}
end

local function is_ignored_parser(lang)
  return vim.tbl_contains(configs.get_ignored_parser_installs(), lang)
end

---@param lang string
---@return string|nil
local function get_revision(lang)
  if #lockfile == 0 then
    load_lockfile()
  end

  local install_info = get_parser_install_info(lang)
  if install_info.revision then
    return install_info.revision
  end

  if lockfile[lang] then
    return lockfile[lang].revision
  end
end

---@param lang string
---@return string|nil
local function get_installed_revision(lang)
  local lang_file = utils.join_path(configs.get_parser_info_dir(), lang .. ".revision")
  if vim.fn.filereadable(lang_file) == 1 then
    return vim.fn.readfile(lang_file)[1]
  end
end

-- Clean path for use in a prefix comparison
---@param input string
---@return string
local function clean_path(input)
  local pth = vim.fn.fnamemodify(input, ":p")
  if fn.has "win32" == 1 then
    pth = pth:gsub("/", "\\")
  end
  return pth
end

-- Checks if parser is installed with nvim-treesitter
---@param lang string
---@return boolean
local function is_installed(lang)
  local matched_parsers = vim.api.nvim_get_runtime_file("parser/" .. lang .. ".so", true) or {}
  local install_dir = configs.get_parser_install_dir()
  if not install_dir then
    return false
  end
  install_dir = clean_path(install_dir)
  for _, path in ipairs(matched_parsers) do
    local abspath = clean_path(path)
    if vim.startswith(abspath, install_dir) then
      return true
    end
  end
  return false
end

---@param lang string
---@return boolean
local function needs_update(lang)
  local revision = get_revision(lang)
  return not revision or revision ~= get_installed_revision(lang)
end

---@return string[]
local function outdated_parsers()
  return vim.tbl_filter(function(lang) ---@param lang string
    return is_installed(lang) and needs_update(lang)
  end, info.installed_parsers())
end

---@param handle userdata
---@param is_stderr boolean
local function onread(handle, is_stderr)
  return function(_, data)
    if data then
      if is_stderr then
        complete_error_output[handle] = (complete_error_output[handle] or "") .. data
      else
        complete_std_output[handle] = (complete_std_output[handle] or "") .. data
      end
    end
  end
end

function M.iter_cmd(cmd_list, i, lang, success_message)
  if i == 1 then
    started_commands = started_commands + 1
  end
  if i == #cmd_list + 1 then
    finished_commands = finished_commands + 1
    return print(get_job_status() .. " " .. success_message)
  end

  local attr = cmd_list[i]
  if attr.info then
    print(get_job_status() .. " " .. attr.info)
  end

  if attr.opts and attr.opts.args and M.command_extra_args[attr.cmd] then
    vim.list_extend(attr.opts.args, M.command_extra_args[attr.cmd])
  end

  if type(attr.cmd) == "function" then
    local ok, err = pcall(attr.cmd)
    if ok then
      M.iter_cmd(cmd_list, i + 1, lang, success_message)
    else
      failed_commands = failed_commands + 1
      finished_commands = finished_commands + 1
      return api.nvim_err_writeln(
        (attr.err or ("Failed to execute the following command:\n" .. vim.inspect(attr))) .. "\n" .. vim.inspect(err)
      )
    end
  else
    local handle
    local stdout = luv.new_pipe(false)
    local stderr = luv.new_pipe(false)
    attr.opts.stdio = { nil, stdout, stderr }
    ---@type userdata
    handle = luv.spawn(
      attr.cmd,
      attr.opts,
      vim.schedule_wrap(function(code)
        if code ~= 0 then
          stdout:read_stop()
          stderr:read_stop()
        end
        stdout:close()
        stderr:close()
        handle:close()
        if code ~= 0 then
          failed_commands = failed_commands + 1
          finished_commands = finished_commands + 1
          if complete_std_output[handle] and complete_std_output[handle] ~= "" then
            print(complete_std_output[handle])
          end

          local err_msg = complete_error_output[handle] or ""
          api.nvim_err_writeln(
            "nvim-treesitter["
              .. lang
              .. "]: "
              .. (attr.err or ("Failed to execute the following command:\n" .. vim.inspect(attr)))
              .. "\n"
              .. err_msg
          )
          return
        end
        M.iter_cmd(cmd_list, i + 1, lang, success_message)
      end)
    )
    luv.read_start(stdout, onread(handle, false))
    luv.read_start(stderr, onread(handle, true))
  end
end

---@param cmd Command
---@return string command
local function get_command(cmd)
  local options = ""
  if cmd.opts and cmd.opts.args then
    if M.command_extra_args[cmd.cmd] then
      vim.list_extend(cmd.opts.args, M.command_extra_args[cmd.cmd])
    end
    for _, opt in ipairs(cmd.opts.args) do
      options = string.format("%s %s", options, opt)
    end
  end

  local command = string.format("%s %s", cmd.cmd, options)
  if cmd.opts and cmd.opts.cwd then
    command = shell.make_directory_change_for_command(cmd.opts.cwd, command)
  end
  return command
end

---@param cmd_list Command[]
---@return boolean
local function iter_cmd_sync(cmd_list)
  for _, cmd in ipairs(cmd_list) do
    if cmd.info then
      print(cmd.info)
    end

    if type(cmd.cmd) == "function" then
      cmd.cmd()
    else
      local ret = vim.fn.system(get_command(cmd))
      if vim.v.shell_error ~= 0 then
        print(ret)
        api.nvim_err_writeln(
          (cmd.err and cmd.err .. "\n" or "") .. "Failed to execute the following command:\n" .. vim.inspect(cmd)
        )
        return false
      end
    end
  end

  return true
end

---@param cache_folder string
---@param install_folder string
---@param lang string
---@param repo InstallInfo
---@param with_sync boolean
---@param generate_from_grammar boolean
local function run_install(cache_folder, install_folder, lang, repo, with_sync, generate_from_grammar)
  parsers.reset_cache()

  local path_sep = utils.get_path_sep()

  local project_name = "tree-sitter-" .. lang
  local maybe_local_path = vim.fn.expand(repo.url)
  local from_local_path = vim.fn.isdirectory(maybe_local_path) == 1
  if from_local_path then
    repo.url = maybe_local_path
  end

  ---@type string compile_location only needed for typescript installs.
  local compile_location
  if from_local_path then
    compile_location = repo.url
  else
    local repo_location = project_name
    if repo.location then
      repo_location = repo_location .. "/" .. repo.location
    end
    repo_location = repo_location:gsub("/", path_sep)
    compile_location = utils.join_path(cache_folder, repo_location)
  end
  local parser_lib_name = utils.join_path(install_folder, lang) .. ".so"

  generate_from_grammar = repo.requires_generate_from_grammar or generate_from_grammar

  if generate_from_grammar and vim.fn.executable "tree-sitter" ~= 1 then
    api.nvim_err_writeln "tree-sitter CLI not found: `tree-sitter` is not executable!"
    if repo.requires_generate_from_grammar then
      api.nvim_err_writeln(
        "tree-sitter CLI is needed because `"
          .. lang
          .. "` is marked that it needs "
          .. "to be generated from the grammar definitions to be compatible with nvim!"
      )
    end
    return
  else
    if not M.ts_generate_args then
      local ts_cli_version = utils.ts_cli_version()
      if ts_cli_version and vim.split(ts_cli_version, " ")[1] > "0.20.2" then
        M.ts_generate_args = { "generate", "--abi", vim.treesitter.language_version }
      else
        M.ts_generate_args = { "generate" }
      end
    end
  end
  if generate_from_grammar and vim.fn.executable "node" ~= 1 then
    api.nvim_err_writeln "Node JS not found: `node` is not executable!"
    return
  end
  local cc = shell.select_executable(M.compilers)
  if not cc then
    api.nvim_err_writeln('No C compiler found! "' .. table.concat(
      vim.tbl_filter(function(c) ---@param c string
        return type(c) == "string"
      end, M.compilers),
      '", "'
    ) .. '" are not executable.')
    return
  end

  local revision = repo.revision
  if not revision and configs.get_update_strategy() == "lockfile" then
    revision = get_revision(lang)
  end

  ---@class Command
  ---@field cmd string
  ---@field info string
  ---@field err string
  ---@field opts CmdOpts

  ---@class CmdOpts
  ---@field args string[]
  ---@field cwd string

  ---@type Command[]
  local command_list = {}
  if not from_local_path then
    vim.list_extend(command_list, { shell.select_install_rm_cmd(cache_folder, project_name) })
    vim.list_extend(
      command_list,
      shell.select_download_commands(repo, project_name, cache_folder, revision, M.prefer_git)
    )
  end
  if generate_from_grammar then
    if repo.generate_requires_npm then
      if vim.fn.executable "npm" ~= 1 then
        api.nvim_err_writeln("`" .. lang .. "` requires NPM to be installed from grammar.js")
        return
      end
      vim.list_extend(command_list, {
        {
          cmd = "npm",
          info = "Installing NPM dependencies of " .. lang .. " parser",
          err = "Error during `npm install` (required for parser generation of " .. lang .. " with npm dependencies)",
          opts = {
            args = { "install" },
            cwd = compile_location,
          },
        },
      })
    end
    vim.list_extend(command_list, {
      {
        cmd = vim.fn.exepath "tree-sitter",
        info = "Generating source files from grammar.js...",
        err = 'Error during "tree-sitter generate"',
        opts = {
          args = M.ts_generate_args,
          cwd = compile_location,
        },
      },
    })
  end
  vim.list_extend(command_list, {
    shell.select_compile_command(repo, cc, compile_location),
    shell.select_mv_cmd("parser.so", parser_lib_name, compile_location),
    {
      cmd = function()
        vim.fn.writefile({ revision or "" }, utils.join_path(configs.get_parser_info_dir() or "", lang .. ".revision"))
      end,
    },
    { -- auto-attach modules after installation
      cmd = reattach_if_possible_fn(lang, true),
    },
  })
  if not from_local_path then
    vim.list_extend(command_list, { shell.select_install_rm_cmd(cache_folder, project_name) })
  end

  if with_sync then
    if iter_cmd_sync(command_list) == true then
      print("Treesitter parser for " .. lang .. " has been installed")
    end
  else
    M.iter_cmd(command_list, 1, lang, "Treesitter parser for " .. lang .. " has been installed")
  end
end

---@param lang string
---@param ask_reinstall boolean|string
---@param cache_folder string
---@param install_folder string
---@param with_sync boolean
---@param generate_from_grammar boolean
local function install_lang(lang, ask_reinstall, cache_folder, install_folder, with_sync, generate_from_grammar)
  if is_installed(lang) and ask_reinstall ~= "force" then
    if not ask_reinstall then
      return
    end

    local yesno = fn.input(lang .. " parser already available: would you like to reinstall ? y/n: ")
    print "\n "
    if not string.match(yesno, "^y.*") then
      return
    end
  end

  local ok, install_info = pcall(get_parser_install_info, lang, true)
  if not ok then
    vim.notify("Installation not possible: " .. install_info, vim.log.levels.ERROR)
    if not parsers.get_parser_configs()[lang] then
      vim.notify(
        "See https://github.com/nvim-treesitter/nvim-treesitter/#adding-parsers on how to add a new parser!",
        vim.log.levels.INFO
      )
    end
    return
  end

  run_install(cache_folder, install_folder, lang, install_info, with_sync, generate_from_grammar)
end

---@class InstallOptions
---@field with_sync boolean
---@field ask_reinstall boolean|string
---@field generate_from_grammar boolean
---@field exclude_configured_parsers boolean

-- Install a parser
---@param options? InstallOptions
---@return function
local function install(options)
  options = options or {}
  local with_sync = options.with_sync
  local ask_reinstall = options.ask_reinstall
  local generate_from_grammar = options.generate_from_grammar
  local exclude_configured_parsers = options.exclude_configured_parsers

  return function(...)
    if fn.executable "git" == 0 then
      return api.nvim_err_writeln "Git is required on your system to run this command"
    end

    local cache_folder, err = utils.get_cache_dir()
    if err then
      return api.nvim_err_writeln(err)
    end
    assert(cache_folder)

    local install_folder
    install_folder, err = configs.get_parser_install_dir()
    if err then
      return api.nvim_err_writeln(err)
    end
    assert(install_folder)

    local languages ---@type string[]
    local ask ---@type boolean|string
    if ... == "all" then
      languages = parsers.available_parsers()
      ask = false
    else
      languages = vim.tbl_flatten { ... }
      ask = ask_reinstall
    end

    if exclude_configured_parsers then
      languages = utils.difference(languages, configs.get_ignored_parser_installs())
    end

    if #languages > 1 then
      reset_progress_counter()
    end

    for _, lang in ipairs(languages) do
      install_lang(lang, ask, cache_folder, install_folder, with_sync, generate_from_grammar)
    end
  end
end

function M.setup_auto_install()
  vim.api.nvim_create_autocmd("FileType", {
    pattern = { "*" },
    callback = function()
      local lang = parsers.get_buf_lang()
      if parsers.get_parser_configs()[lang] and not is_installed(lang) and not is_ignored_parser(lang) then
        install() { lang }
      end
    end,
  })
end

function M.update(options)
  options = options or {}
  return function(...)
    M.lockfile = {}
    reset_progress_counter()
    if ... and ... ~= "all" then
      ---@type string[]
      local languages = vim.tbl_flatten { ... }
      local installed = 0
      for _, lang in ipairs(languages) do
        if (not is_installed(lang)) or (needs_update(lang)) then
          installed = installed + 1
          install {
            ask_reinstall = "force",
            with_sync = options.with_sync,
          }(lang)
        end
      end
      if installed == 0 then
        utils.notify "Parsers are up-to-date!"
      end
    else
      local parsers_to_update = configs.get_update_strategy() == "lockfile" and outdated_parsers()
        or info.installed_parsers()
      if #parsers_to_update == 0 then
        utils.notify "All parsers are up-to-date!"
      end
      for _, lang in pairs(parsers_to_update) do
        install {
          ask_reinstall = "force",
          exclude_configured_parsers = true,
          with_sync = options.with_sync,
        }(lang)
      end
    end
  end
end

function M.uninstall(...)
  if vim.tbl_contains({ "all" }, ...) then
    reset_progress_counter()
    local installed = info.installed_parsers()
    for _, langitem in pairs(installed) do
      M.uninstall(langitem)
    end
  elseif ... then
    local ensure_installed_parsers = configs.get_ensure_installed_parsers()
    if ensure_installed_parsers == "all" then
      ensure_installed_parsers = parsers.available_parsers()
    end
    ensure_installed_parsers = utils.difference(ensure_installed_parsers, configs.get_ignored_parser_installs())

    ---@type string[]
    local languages = vim.tbl_flatten { ... }
    for _, lang in ipairs(languages) do
      local install_dir, err = configs.get_parser_install_dir()
      if err then
        return api.nvim_err_writeln(err)
      end

      if vim.tbl_contains(ensure_installed_parsers, lang) then
        vim.notify(
          "Uninstalling "
            .. lang
            .. '. But the parser is still configured in "ensure_installed" setting of nvim-treesitter.'
            .. " Please consider updating your config!",
          vim.log.levels.ERROR
        )
      end

      local parser_lib = utils.join_path(install_dir, lang) .. ".so"
      local all_parsers = vim.api.nvim_get_runtime_file("parser/" .. lang .. ".so", true)
      if vim.fn.filereadable(parser_lib) == 1 then
        local command_list = {
          shell.select_rm_file_cmd(parser_lib, "Uninstalling parser for " .. lang),
          {
            cmd = function()
              local all_parsers_after_deletion = vim.api.nvim_get_runtime_file("parser/" .. lang .. ".so", true)
              if #all_parsers_after_deletion > 0 then
                vim.notify(
                  "Tried to uninstall parser for "
                    .. lang
                    .. "! But the parser is still installed (not by nvim-treesitter)."
                    .. " Please delete the following files manually: "
                    .. table.concat(all_parsers_after_deletion, ", "),
                  vim.log.levels.ERROR
                )
              end
            end,
          },
          { -- auto-reattach or detach modules after uninstallation
            cmd = reattach_if_possible_fn(lang, false),
          },
        }
        M.iter_cmd(command_list, 1, lang, "Treesitter parser for " .. lang .. " has been uninstalled")
      elseif #all_parsers > 0 then
        vim.notify(
          "Parser for "
            .. lang
            .. " is installed! But not by nvim-treesitter! Please manually remove the following files: "
            .. table.concat(all_parsers, ", "),
          vim.log.levels.ERROR
        )
      end
    end
  end
end

function M.write_lockfile(verbose, skip_langs)
  local sorted_parsers = {} ---@type Parser[]
  -- Load previous lockfile
  load_lockfile()
  skip_langs = skip_langs or {}

  for k, v in pairs(parsers.get_parser_configs()) do
    table.insert(sorted_parsers, { name = k, parser = v })
  end

  ---@param a Parser
  ---@param b Parser
  table.sort(sorted_parsers, function(a, b)
    return a.name < b.name
  end)

  for _, v in ipairs(sorted_parsers) do
    if not vim.tbl_contains(skip_langs, v.name) then
      -- I'm sure this can be done in aync way with iter_cmd
      local sha ---@type string
      if v.parser.install_info.branch then
        sha = vim.split(
          vim.fn.systemlist(
            "git ls-remote " .. v.parser.install_info.url .. " | grep refs/heads/" .. v.parser.install_info.branch
          )[1],
          "\t"
        )[1]
      else
        sha = vim.split(vim.fn.systemlist("git ls-remote " .. v.parser.install_info.url)[1], "\t")[1]
      end
      lockfile[v.name] = { revision = sha }
      if verbose then
        print(v.name .. ": " .. sha)
      end
    else
      print("Skipping " .. v.name)
    end
  end

  if verbose then
    print(vim.inspect(lockfile))
  end
  vim.fn.writefile(
    vim.fn.split(vim.fn.json_encode(lockfile), "\n"),
    utils.join_path(utils.get_package_path(), "lockfile.json")
  )
end

M.ensure_installed = install { exclude_configured_parsers = true }
M.ensure_installed_sync = install { with_sync = true, exclude_configured_parsers = true }

M.commands = {
  TSInstall = {
    run = install { ask_reinstall = true },
    ["run!"] = install { ask_reinstall = "force" },
    args = {
      "-nargs=+",
      "-bang",
      "-complete=custom,nvim_treesitter#installable_parsers",
    },
  },
  TSInstallFromGrammar = {
    run = install { generate_from_grammar = true, ask_reinstall = true },
    ["run!"] = install { generate_from_grammar = true, ask_reinstall = "force" },
    args = {
      "-nargs=+",
      "-bang",
      "-complete=custom,nvim_treesitter#installable_parsers",
    },
  },
  TSInstallSync = {
    run = install { with_sync = true, ask_reinstall = true },
    ["run!"] = install { with_sync = true, ask_reinstall = "force" },
    args = {
      "-nargs=+",
      "-bang",
      "-complete=custom,nvim_treesitter#installable_parsers",
    },
  },
  TSUpdate = {
    run = M.update {},
    args = {
      "-nargs=*",
      "-complete=custom,nvim_treesitter#installed_parsers",
    },
  },
  TSUpdateSync = {
    run = M.update { with_sync = true },
    args = {
      "-nargs=*",
      "-complete=custom,nvim_treesitter#installed_parsers",
    },
  },
  TSUninstall = {
    run = M.uninstall,
    args = {
      "-nargs=+",
      "-complete=custom,nvim_treesitter#installed_parsers",
    },
  },
}

return M
