local Context = require "cave.context"
local Meta = require "cave.meta"
local Module = require "cave.python.module"
local Path = require "cave.path"
local Runnable = require "cave.python.runnable"
local Script = require "cave.python.script"
local Task = require "cave.task"

local List = Meta.List
local Map = Meta.Map
local Str = Meta.String
local validate = Meta.validate

---@class cave.Python.Interpreter
---@field id string
---@field path cave.Path
---@field args string[]
---@field env table<string, string>
---@field runnables table<string, cave.Python.Runnable>
---@field context cave.Context
local Interpreter = Meta.derive "Python.Interpreter"

---@return string
function Interpreter:valid_path() return self.path:executable():tostring() end

---@return overseer.TemplateDefinition[]
function Interpreter:templates()
  local templates = {}
  for _, runnable in pairs(self.runnables) do
    vim.list_extend(templates, { self:run_template(runnable), self:debug_template(runnable) })
  end
  return templates
end

---@param runnable cave.Python.Runnable
---@return overseer.TemplateDefinition
function Interpreter:run_template(runnable)
  local name = ("python.%s.run.%s"):format(self.id, runnable.id)
  local script, module = runnable:concrete()
  local args = vim.list_extend({}, self.args)
  vim.list_extend(
    args,
    (script and { script:valid_file() }) or (module and { "-m", module.name }) or error "Unsupported runnable"
  )
  vim.list_extend(args, runnable.args)
  local template_definition = {
    name = name,
    builder = function()
      ---@type overseer.TaskDefinition
      local task_definition = {
        name = name,
        cmd = { self:valid_path() },
        args = args,
        env = vim.tbl_extend("keep", runnable.env, self.env),
        cwd = runnable:valid_cwd(),
        components = { { "defaults" } },
      }
      return task_definition
    end,
    params = {},
    tags = { Task.Tag.Run },
  }
  return template_definition
end

---@param runnable cave.Python.Runnable
---@return overseer.TemplateDefinition
function Interpreter:debug_template(runnable)
  local name = ("python.%s.debug.%s"):format(self.id, runnable.id)
  local template_definition = {}
  template_definition.builder = function()
    local script, module = runnable:concrete()

    ---@type DebugpyLaunchConfig
    local dap_config = {
      name = name,
      type = "python",
      request = "launch",
      module = module and module.name,
      program = script and script:valid_file(),
      cwd = runnable:valid_cwd(),
      args = runnable.args,
      env = vim.tbl_extend("keep", runnable.env, self.env),
      python = vim.list_extend({ self:valid_path() }, self.args),
    }

    if vim.tbl_isempty(dap_config.env) then dap_config.env = nil end

    ---@type overseer.TaskDefinition
    local task_definition = {
      name = name,
      cmd = {},
      components = { { "defaults" }, { "dap", config = dap_config } },
    }
    return task_definition
  end
  template_definition.params = {}
  template_definition.tags = { Task.Tag.Debug }
  template_definition.name = name
  return template_definition
end

---@class cave.Python.Interpreter.Factory
---@field id_ string?
---@field path_ cave.Path?
---@field args_ string[]
---@field env_ table<string, string>
---@field runnables_ cave.Python.Runnable.Factory[]
---@field context_ cave.Context
local Factory = Meta.derive "Python.Interpreter.Factory"

---@param context cave.Context
function Factory:init(context)
  self.args_ = {}
  self.env_ = {}
  self.runnables_ = {}
  self.context_ = context
end

---@param context cave.Context
---@return cave.Python.Interpreter.Factory
function Factory.new(context)
  validate { context = { context, Context } }
  local factory = setmetatable({}, Factory)
  factory:init(context)
  return factory
end

---@return string
function Factory:get_id() return self.id_ or "python" end

---@return cave.Path
function Factory:get_path() return self.path_ or Path.new "python" end

---@return string[]
function Factory:get_args() return self.args_ end

---@return table<string, string>
function Factory:get_env() return self.env_ end

---@return cave.Python.Runnable.Factory[]
function Factory:get_runnables() return self.runnables_ end

---@param id string
---@return cave.Python.Interpreter.Factory
function Factory:id(id)
  validate { id = { id, Str } }
  self.id_ = id
  return self
end

---@param path_like cave.PathLike
---@return cave.Python.Interpreter.Factory
function Factory:path(path_like)
  validate { path_like = { path_like, Path.Like } }
  self.path_ = Path.like(path_like)
  return self
end

---@param args string[]
---@return cave.Python.Interpreter.Factory
function Factory:args(args)
  validate { args = { args, List(Str) } }
  vim.list_extend(self.args_, args)
  return self
end

---@param arg string
---@return cave.Python.Interpreter.Factory
function Factory:arg(arg) return self:args { arg } end

---@param env table<string, string>
---@return cave.Python.Interpreter.Factory
function Factory:env(env)
  validate { env = { env, Map(Str, Str) } }
  vim.tbl_extend("error", self.env_, env)
  return self
end

---@param name string
---@return cave.Python.Module.Factory
function Factory:module(name)
  validate { name = { name, Str } }
  local module_factory = Module.Factory.new(name, self.context_)
  table.insert(self.runnables_, module_factory)
  return module_factory
end

---@param file_path_like cave.PathLike
---@return cave.Python.Script.Factory
function Factory:script(file_path_like)
  validate { file = { file_path_like, Path.Like } }
  local file = Path.like(file_path_like)
  local script_factory = Script.Factory.new(file, self.context_)
  table.insert(self.runnables_, script_factory)
  return script_factory
end

---@param runnables cave.Python.Runnable.Factory[]
---@return cave.Python.Interpreter.Factory
function Factory:runnables(runnables)
  validate { runnables = { runnables, List(Runnable.Factory) } }
  for _, runnable in ipairs(runnables) do
    table.insert(self.runnables_, runnable:copy())
  end
  return self
end

---@param runnable cave.Python.Runnable.Factory
---@return cave.Python.Interpreter.Factory
function Factory:runnable(runnable) return self:runnables { runnable } end

---@param interpreter cave.Python.Interpreter
function Factory:init_interpreter(interpreter)
  interpreter.id = self:get_id()
  interpreter.path = self:get_path()
  interpreter.args = self:get_args()
  interpreter.env = self:get_env()
  interpreter.runnables = {}
  for _, runnable_factory in pairs(self:get_runnables()) do
    local runnable = runnable_factory:build()
    assert(interpreter.runnables[runnable.id] == nil)
    interpreter.runnables[runnable.id] = runnable
  end
end

---@return cave.Python.Interpreter
function Factory:build()
  local interpreter = setmetatable({}, Interpreter)
  self:init_interpreter(interpreter)
  return interpreter
end

Interpreter.Factory = Factory

return Interpreter