dep/lua/dep.lua

local logger = require('dep.log')
local git = require('dep.git')
local packager = require('dep.package')

---all functions for convenience
---@type table
local M = {}

---@type boolean
local initialized

---performance logging
---@type table
local perf = {}

--- get execution time of a function
---@param name string name of performance output
---@param code function function to run
---@vararg any arguments for code
function M.benchmark(name, code, ...)
  local start = os.clock()
  code(...)
  perf[name] = os.clock() - start
end

--- recurse over all packages and register them
---@param speclist spec[] table of specs
---@param overrides spec? a package spec that is used to override options
function M.registertree(speclist, overrides)
  overrides = overrides or {}

  -- recurse the packages
  for _, spec in pairs(speclist) do

    -- make sure the overrides override and take into account the packages spec
    ---@diagnostic disable-next-line: missing-fields
    overrides = {
      pin = overrides.pin or spec.pin,
      disable = overrides.disable or spec.disable
    }

    local ok = packager:new(spec, overrides)

    -- if erroring print out the spec and the error
    if not ok then
      error(string.format("%s (spec=%s)", err, vim.inspect(spec)))
    end
  end
end

--- reload all packages in package table spec
---@param force boolean|nil force all packages to load
function M.reload(force)
  local reloaded = packager.get_root():loadtree(force)

  if reloaded then
    local ok, err
    M.benchmark("reload", function()
      ok, err = pcall(vim.cmd,
        [[
        silent! helptags ALL
        silent! UpdateRemotePlugins
        ]])
    end)

    if ok then
      logger:log("vim", "reloaded helptags and remote plugins")
    else
      logger:log("error",
        "failed to reload helptags and remote plugins; reason: %s", err)
    end
  end
end

--- check if there's a circular dependency in the package tree
function M.findcycle()
  local index = 0
  local indexes = {}
  local lowlink = {}
  local stack = {}

  -- use tarjan algorithm to find circular dependencies (strongly connected
  -- components)
  local function connect(package)
    indexes[package.id], lowlink[package.id] = index, index
    stack[#stack + 1], stack[package.id] = package, true
    index = index + 1

    for i = 1, #package.dependents do
      local dependent = package.dependents[i]

      if not indexes[dependent.id] then
        local cycle = connect(dependent)
        if cycle then
          return cycle
        else
          lowlink[package.id] = math.min(lowlink[package.id], lowlink[dependent.id])
        end
      elseif stack[dependent.id] then
        lowlink[package.id] = math.min(lowlink[package.id], indexes[dependent.id])
      end
    end

    if lowlink[package.id] == indexes[package.id] then
      local cycle = { package }
      local node

      repeat
        node = stack[#stack]
        stack[#stack], stack[node.id] = nil, nil
        cycle[#cycle + 1] = node
      until node == package

      -- a node is by definition strongly connected to itself ignore single-node
      -- components unless it explicitly specified itself as a dependency
      if #cycle > 2 or package.dependents[package.id] then
        return cycle
      end
    end
  end

  for _, package in pairs(packager.get_packages()) do
    if not indexes[package.id] then
      local cycle = connect(package)
      if cycle then
        return cycle
      end
    end
  end
end

--- sync a tree of plugins
---@param tree package[] tree of plugins
---@param cb function? callback
function M.synctree(tree, cb)
  local progress = 0
  local has_errors = false

  local function done(err)
    progress = progress + 1
    has_errors = has_errors or err

    if progress == #tree then
      -- TODO: implement clean
      -- clean()
      M.reload()

      if has_errors then
        logger:log("error", "there were errors during sync; see :messages or :DepLog for more information")
      else
        logger:log("update", "synchronized %s %s", #tree, #tree == 1 and "package" or "packages")
      end

      if cb then
        cb()
      end
    end
  end

  for _, package in pairs(tree) do
    git.sync(package, done)
  end
end

-- basically the main function of our program
return function(opts)
  logger.pipe = logger:setup()

  --- make comparison for table.sort
  ---@param a table package spec a
  ---@param b table package spec b
  ---@return boolean
  local function comp(a, b)
    -- NOTE: this doesn't have to be in any real order, it just has to be
    -- consistant, thus we can just check if the unicode value of one package
    -- id is less than the other
    return a.id < b.id
  end

  initialized, err = pcall(function()
    packager.set_base_dir(opts.base_dir or vim.fn.stdpath("data").."/site/pack/deps/opt/")
    M.benchmark("load", function()
      -- register all packages
      local root = packager:new({
        "squibid/dep",
        url = "https://git.squi.bid/dep",
        pin = true
      })
      if not root then
        logger:log("error", "couldn't register root package")
        return
      end
      M.registertree(opts)

      -- sort package dependencies
      for _, package in pairs(packager.get_packages()) do
        table.sort(package.requirements, comp)
        table.sort(package.dependents, comp)
      end

      -- make sure there arent any circular dependencies
      M.findcycle()
    end)

    -- load packages
    M.reload()

    --- check if a package should be synced
    ---@param package table package table spec
    ---@return boolean sync
    local function shouldsync(package)
      if opts.sync == "new" or opts.sync == nil then
        return not package.exists
      else
        return opts.sync == "always"
      end
    end

    -- get all package that need syncing
    local targets = {}
    for i, package in pairs(packager.get_packages()) do
      if shouldsync(package) then
        targets[i] = package
      end
    end

    M.synctree(targets)
  end)

  if not initialized then
    logger:log("error", err)
  end

  vim.api.nvim_create_user_command("DepLog", function()
    vim.cmd('vsp '..logger.path)
    vim.opt_local.readonly = true

    local w = vim.uv.new_fs_event()
    local function watch_file(fname)
      local fullpath = vim.api.nvim_call_function(
        'fnamemodify', { fname, ':p' })
      w:start(fullpath, {}, vim.schedule_wrap(function(...)
        vim.api.nvim_command('checktime')
        -- Debounce: stop/start.
        w:stop()
        watch_file(fname)
      end))
    end

    watch_file(logger.path)
  end, {})

  vim.api.nvim_create_user_command("DepSync", function()
    M.synctree(packager.get_packages())
  end, {})

  vim.api.nvim_create_user_command("DepReload", function()
    M.reload()
  end, {})

  logger:cleanup()
end