dep/lua/dep/package.lua

local logger = require('dep.log')

---@class spec
---@field [1] string id
---@field setup function? code to run before the package is loaded
---@field load function? code to run after the package is loaded
---@field config function? code to run after the package is installed/updated
---@field lazy function? code to run which determines when the package is loaded
---@field as string? overrides the short name of the package which is usually set
--- to a substring of all the chars after '/' in spec[1]
---@field url string? the url to the git repository hosting the package
---@field branch string? the branch which the version of the package resides
---@field commit string? the commit which the version of the package resides
---@field disable boolean? if true disables the package from being loaded
---@field pin boolean? if true disables the package from being installed/updated
---@field reqs spec|spec[]|string? packages that this package requires
---@field deps spec|spec[]|string? packages that depend on this package

---@class package
---@field id string id of the package
---@field enabled boolean whether it's going to be used
---@field exists boolean if the package exists on the filesystem
---@field lazy boolean if the package is lazy loaded in any way
---@field added boolean if the package has been added in vim
---@field configured boolean if the package has been configured
---@field lazied boolean if the packages lazy loading has been set
---@field loaded boolean if a package has been loaded
---@field subtree_loaded boolean is the subtree has been loaded
---@field on_config function[] table of functions to run on config
---@field on_setup function[] table of function to run on setup
---@field on_load function[] table of functions to run on load
---@field lazy_load function[] table of functions to run which will tell the package when to load
---@field requirements package[] this package's requirements
---@field dependents package[] packages that require this package
---@field perf table performance metrics for the package
---@field name string the name of the package
---@field url string the url of the package
---@field branch string the branch of the package
---@field dir string the directory of the package
---@field commit string the commit of the package
---@field pin boolean whether to pin the package or not
local package = {}

--- the base directory for the packages
---@type string
local base_dir

--- the root package
---@type package
local root

--- list of all package in dep
---@type package[]
local packages = {}

--- check a spec to see if it's correct
---@param spec spec|string the specification to check
---@return spec|false spec if the spec is ok or false
local function check_spec(spec)
  -- make sure spec is a table
  if type(spec) == "string" then
    spec = { spec }
  end

  -- make sure all the data is correct
  do -- spec[1]
    if type(spec[1]) ~= "string" then
      logger:log("spec", "spec[1] must be a string")
      return false
    end

    local name = spec[1]:match("^[%w-_.]+/([%w-_.]+)$")
    if not name then
      logger:log("spec", 'invalid name "%s"; must be in the format "user/package"', spec[1])
      return false
    end
  end

  if spec.setup ~= nil then -- spec.setup
    if type(spec.setup) ~= "function" then
      logger:log("spec", "spec.setup must be a function in %s", spec[1])
      return false
    end
  end

  if spec.load ~= nil then -- spec.load
    if type(spec.load) ~= "function" then
      logger:log("spec", "spec.load must be a function in %s", spec[1])
      return false
    end
  end

  if spec.config ~= nil then -- spec.config
    if type(spec.config) ~= "function" then
      logger:log("spec", "spec.config must be a function in %s", spec[1])
      return false
    end
  end

  if spec.lazy ~= nil then -- spec.lazy
    if type(spec.lazy) ~= "function" then
      logger:log("spec", "spec.lazy must be a function in %s", spec[1])
      return false
    end
  end

  if spec.as ~= nil then -- spec.as
    if type(spec.as) ~= "string" then
      logger:log("spec", "spec.as must be a string in %s", spec[1])
      return false
    end
  end

  if spec.url ~= nil then -- spec.url
    if type(spec.url) ~= "string" then
      logger:log("spec", "spec.url must be a string in %s", spec[1])
      return false
    end
  end

  if spec.branch ~= nil then -- spec.branch
    if type(spec.branch) ~= "string" then
      logger:log("spec", "spec.branch must be a string in %s", spec[1])
      return false
    end
  end

  if spec.commit ~= nil then -- spec.commit
    if type(spec.commit) ~= "string" then
      logger:log("spec", "spec.commit must be a string in %s", spec[1])
      return false
    end
  end

  if spec.disable ~= nil then -- spec.disable
    if type(spec.disable) ~= "boolean" then
      logger:log("spec", "spec.disable must be a boolean in %s", spec[1])
      return false
    end
  end

  if spec.pin ~= nil then -- spec.pin
    if type(spec.pin) ~= "boolean" then
      logger:log("spec", "spec.pin must be a boolean in %s", spec[1])
      return false
    end
  end

  if spec.reqs ~= nil then -- spec.reqs
    local is = type(spec.reqs)
    if is ~= "table" and is ~= "string" then
      logger:log("spec", "spec.reqs must be a table or a string in %s", spec[1])
      return false
    end

    -- turn an id into a spec
    if (is == "string") then
      spec.reqs = { spec.reqs }
    end
  end

  if spec.deps ~= nil then -- spec.deps
    local is = type(spec.deps)
    if is ~= "table" and is ~= "string" then
      logger:log("spec", "spec.deps must be a table or a string in %s", spec[1])
      return false
    end

    -- turn an id into a spec
    if (is == "string") then
      spec.deps = { spec.deps }
    end
  end

  return spec
end

--- tell the parent it has a child and the child it has a parent
---@param parent package? parent package if nil defaults to self
---@param child package child package
function package:link_dependency(parent, child)
  parent = parent or self

  if not parent.dependents[child.id] then
    parent.dependents[child.id] = child
    table.insert(parent.dependents, child)
  end

  if not child.requirements[parent.id] then
    child.requirements[parent.id] = parent
    table.insert(child.requirements, parent)
  end
end

--- create a new package instance
---@param spec spec|string a package spec to use for the new package
---@param overrides spec? a package spec that is used to overried this package
---@return package|false package an instance of the package or false on failure
---@nodisacard
function package:new(spec, overrides)
  overrides = overrides or {}

  -- ensure that the spec is ok
  local new_spec = check_spec(spec)
  if new_spec == false then
    logger:log("spec", vim.inspect(spec))
    logger:log("error", "spec check failed, check DepLog")
    return false
  else
    spec = new_spec
  end

  -- start initializing the package
  local id = spec[1]

  local o = packages[id] or {}
  self.__index = self
  setmetatable(o, self)

  -- if package hasn't been registered already, get the inital spec regisitered
  if not o.id then
    o.id = id
    o.enabled = true
    o.exists = false
    o.lazy = false
    o.added = false
    o.lazied = false
    o.configured = false
    o.loaded = false
    o.subtree_loaded = false
    o.on_config = {}
    o.on_setup = {}
    o.on_load = {}
    o.lazy_load = {}

    o.requirements = {}
    o.dependents = {}
    o.perf = {}

    packages[id] = o
  end

  o.name = spec.as or o.name or id:match("^[%w-_.]+/([%w-_.]+)$")
  o.url = spec.url or o.url or ("https://github.com/"..id..".git")
  o.branch = spec.branch or o.branch
  o.dir = base_dir..o.name
  o.commit = spec.commit
  o.pin = overrides.pin or spec.pin or o.pin
  o.enabled = not overrides.disable and not spec.disable and o.enabled
  o.lazy = spec.lazy ~= nil or o.lazy

  -- make sure that the package exists
  o.exists = vim.fn.isdirectory(o.dir) ~= 0
  o.configured = o.exists

  -- register all the callback functions
  if spec.config ~= nil then
    table.insert(o.on_config, spec.config)
  end
  if spec.setup ~= nil then
    table.insert(o.on_setup, spec.setup)
  end
  if spec.load ~= nil then
    table.insert(o.on_load, spec.load)
  end
  if spec.lazy ~= nil then
    table.insert(o.lazy_load, spec.lazy)
  end

  -- if the current package isn't the root package then it depends on the root
  -- package
  if root and o ~= root then
    o:link_dependency(root, o)
  elseif not root then
    root = o
  end

  -- link the dependencies
  if spec.reqs then
    ---it is the correct type as asserted in check_spec()
    ---@diagnostic disable-next-line: param-type-mismatch
    for _, req in pairs(spec.reqs) do
      local pkg = package:new(req)
      if type(pkg) == "table" then
        o:link_dependency(pkg, o)
      end
    end
  end

  -- and link the dependents
  if spec.deps then
    ---it is the correct type as asserted in check_spec()
    ---@diagnostic disable-next-line: param-type-mismatch
    for _, dep in pairs(spec.deps) do
      local pkg = package:new(dep)
      if not pkg then
        return false
      end
      o:link_dependency(o, pkg)

      -- if the child package is lazy loaded make sure the child package
      -- is only loaded when the parent package has finished loading
      if o.lazy then
        table.insert(o.on_load, function()
          local ok = o:loadtree(true)
          if not ok then
            logger:log("lazy",
              "failed to run loadtree for %s, some packages may not be loaded",
              o.id)
          end
        end)

        -- tell the dep that it's gonna be lazy
        pkg.lazy = true
        table.insert(pkg.lazy_load, function(_) end)
      end
    end
  end

  return o
end

--- set the base directory for packages
---@param _base_dir string base directory
function package.set_base_dir(_base_dir)
  base_dir = _base_dir
end

--- get the base directory for packages
---@return string base_dir
---@nodiscard
function package.get_base_dir()
  return base_dir
end

--- get the root directory
---@return package root
---@nodiscard
function package.get_root()
  return root
end

--- get the packages in dep
---@return package root
---@nodiscard
function package.get_packages()
  return packages
end

--- run specified hooks on the current package
---@param type "on_load"|"on_config"|"on_setup" which hook to run
---@return boolean, string|nil
function package:runhooks(type)
  local hooks = self[type]
  if #hooks == 0 then
    return true
  end

  local start = os.clock()

  -- chdir into the package directory to make running external commands
  -- from hooks easier.
  local last_cwd = vim.fn.getcwd()
  vim.fn.chdir(self.dir)

  for i = 1, #hooks do
    local ok, err = pcall(hooks[i])
    if not ok then
      vim.fn.chdir(last_cwd)

      return false, err
    end
  end

  vim.fn.chdir(last_cwd)
  self.perf[type] = os.clock() - start

  logger:log("hook", "triggered %d %s %s for %s", #hooks, type,
    #hooks == 1 and "hook" or "hooks", self.id)

  return true
end

--- make sure a package has been loaded
---@param force boolean? force lazy packages to load
---@return boolean|table return true or false if loaded or package spec if lazy loaded
function package:ensureadded(force)
  --- load a package
  ---@param pkg package
  local function loadpkg(pkg)
    -- make sure to load the dependencies first
    for _, p in pairs(pkg.requirements) do
      if not p.loaded then
        p:ensureadded(true)
      end
    end

    -- run setup hooks
    pkg:runhooks("on_setup")

    -- now start loading our plugin
    local start = os.clock()

    -- trigger the packadd for the plugin
    ---@diagnostic disable-next-line: param-type-mismatch
    local ok, err = pcall(vim.cmd, "packadd "..pkg.name)
    if not ok then
      return false, err
    end

    pkg.added = true
    pkg.perf.pack = os.clock() - start
    logger:log("vim", "packadd completed for %s", pkg.id)

    -- set the package to loaded
    pkg.loaded = true
    logger:log("load", "loaded %s", pkg.id)

    -- trigger the on_load hooks
    ok, err = pkg:runhooks("on_load")
    if not ok then
      logger:log("error", "failed to load %s; reason: %s", pkg.id, err)
      return
    end
  end

  -- make sure the package is lazy loaded if need be
  if not self.added and not self.loaded and not self.lazy or force then
    loadpkg(self)
  elseif not self.added and self.lazy then
    logger:log("lazy", "registering %d lazy hooks for %s", #self.lazy_load,
      self.id)
    self.lazied = true
    for _, load_cond in pairs(self.lazy_load) do
      -- configure the lazy loader for the user
      local l = require('lazy.utils'):new()
      if l == true then
        logger:log("lazy", "failed to get lazy utils")
        return false
      end
      l:set_load(function()
        logger:log("lazy", "triggered %d lazy hooks for %s", #self.lazy_load,
          self.id)
        loadpkg(self)
      end)

      -- run it
      load_cond(l)
    end
    return self
  end

  return true
end

--- load all packages in package tree
---@param force boolean? force lazy packages to load
---@return boolean boolean if tree was successfully loaded
---@nodiscard
function package:loadtree(force)
  -- if the package doesn't exist or isn't enabled then don't load it
  if not self.exists or not self.enabled then
    return false
  end

  -- if the subtree is loaded then it's already loaded unless it needs forcing
  if not force and self.subtree_loaded then
    return true
  end

  -- if the package isn't lazy check that it's requirements are loaded
  if not self.lazy then
    for _, requirement in pairs(self.requirements) do
      if not requirement.loaded and not requirement.lazy then
        logger:log("error", "failed to load %s; requirement: %s isn't loaded",
          self.id, requirement.id)
        return false
      end
    end
  end

  -- if the package isn't loaded and isn't lazy then it should probably be
  -- loaded
  if not self.loaded then
    local ok, err = self:ensureadded(force)
    if not ok then
      logger:log("error", "failed to load %s; reason: %s", self.id, err)
      return false
    end
  end

  self.subtree_loaded = true

  -- make sure the dependants are loaded
  for _, dependant in pairs(self.dependents) do
    self.subtree_loaded = dependant:loadtree(force) and self.subtree_loaded
  end

  return self.subtree_loaded
end

--- unconfigure a packages tree
function package:unconfiguretree()
  -- unconfigure requirements
  for _, requirement in pairs(self.requirements) do
    requirement.subtree_loaded = false
  end

  -- unconfigure dependents
  for _, dependant in pairs(self.dependents) do
    dependant.loaded = false
    dependant.added = false
    dependant.configured = false

    dependant.subtree_loaded = false
  end
end

--- check a list of packages for any cycles
---@param pkgs package[] list of packages
---@return package[]|false cycle the cycle that was found or false if not found
---@nodisacard
function package.findcycle(pkgs)
  local index = 0
  local indexes = {}
  local lowlink = {}
  local stack = {}

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

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

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

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

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

      -- 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 pkg.dependents[pkg.id] then
        return cycle
      end
    end
  end

  -- actually check the cycle
  for _, pkg in pairs(pkgs) do
    if not indexes[package.id] then
      local cycle = connect(pkg)
      if cycle then
        return cycle
      end
    end
  end

  return false
end

return package