defmodule SvEx.MixProject do
  use Mix.Project

  # `.version` is the single source of truth, bumped per commit by the lefthook
  # post-commit hook (scripts/bump_version.exs). Read it, never store it here.
  # `@external_resource` is what makes a bump recompile this file; without it
  # the version baked into the build lags the file that defines it.
  @version_path __DIR__ |> Path.join(".version")
  @external_resource @version_path
  @version @version_path |> File.read!() |> String.trim()

  # Required by hex: `mix hex.build` exits 1 with "Missing metadata fields:
  # links" without it, so this is not optional metadata.
  #
  # One repository for both outputs -- `installer/sv_ex_new/mix.exs` points
  # here too rather than at an installer repository of its own.
  @source_url "https://github.com/wimwian-org/sv_ex"

  # Set by `bin/check`, which runs every gate in every target itself with
  # arguments chosen per gate. Without this seam it would get the fan-out below
  # on top of its own loop and run the archive's dialyzer and coveralls twice --
  # minutes, in CI, for nothing. See `aliases/0`.
  @no_fanout "SVEX_NO_FANOUT"

  def project do
    [
      app: :sv_ex,
      version: @version,
      elixir: "~> 1.20",
      aliases: aliases(),
      elixirc_paths: elixirc_paths(Mix.env()),
      start_permanent: Mix.env() == :prod,
      # Test modules define structs of their own and implement Vex's Extract
      # protocol for them. Consolidation happens before those files compile, so
      # a consolidated protocol would not see them.
      consolidate_protocols: Mix.env() != :test,
      deps: deps(),
      name: "SvEx",
      description: "Scaffolder for Elixir/Phoenix projects with a Svelte 5 UI layer.",
      test_coverage: [tool: ExCoveralls],
      dialyzer: dialyzer(),
      docs: docs(),
      package: package()
    ]
  end

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      extra_applications: [:logger]
    ]
  end

  # `preferred_cli_env` as a project key is deprecated; `cli/0` is where it
  # lives from Elixir 1.15 on. Without it every coveralls task has to be
  # prefixed with `MIX_ENV=test` by hand, and forgetting once reports coverage
  # for a build that never ran the tests.
  def cli do
    [
      preferred_envs: [
        coveralls: :test,
        "coveralls.detail": :test,
        "coveralls.html": :test,
        "coveralls.json": :test,
        dialyzer: :dev,
        docs: :dev,
        doctor: :dev
      ]
    ]
  end

  # Vendored rather than resolved as Hex dependencies: SvEx is installed inside
  # someone else's project, and every requirement it declared would constrain
  # that project's resolution. They live under `lib/sv_ex/vendor/`, matching
  # their `SvEx.Vendor.*` module names, so `lib` picks them up with no separate
  # elixirc_paths entry. See lib/sv_ex/vendor/README.md.

  # The custom Credo checks under `credo/` are compiled in :test so the suite
  # can call them directly -- Credo itself loads them via `requires:` in
  # .credo.exs, which runs in :dev where they are not compiled.
  defp elixirc_paths(:test), do: ["lib", "credo/checks", "test/support"]
  defp elixirc_paths(_env), do: ["lib"]

  # `installer/sv_ex_new` is a build target of its own -- its own mix.exs, deps,
  # .credo.exs, .formatter.exs and test suite. A root `mix test` compiles `lib/`
  # and reaches not one line of it, which is why a root `mix coveralls` never
  # reported a figure for the archive. These aliases run the root task first and
  # then fan it out into every nested target.
  #
  # Targets are discovered from `installer/*/mix.exs` -- the same glob
  # `.credo.exs` and `bin/check` use -- so adding or renaming one needs no edit
  # here.
  #
  # HOW MIX SPLITS THE ARGUMENTS, because it decides what these can and cannot
  # do: in an alias list, the entry NAMED AFTER the alias receives the command
  # line's arguments and every entry after it receives NOTHING
  # (`Mix.Task.run_alias/6` in Elixir's own mix). So `mix test --seed 1` seeds
  # the root run and the archive runs its suite plain. That is the right way
  # round rather than a limitation worked around: `mix test test/sv_ex/x_test.exs`
  # names a path that exists in the root and not in the archive, so forwarding it
  # would fail rather than narrow.
  #
  # `format` is deliberately NOT here. It is the one task whose fan-out has to
  # change with the arguments, and it cannot see them: `mix format
  # --check-formatted` would check the root and REFORMAT the archive, turning
  # the read-only gate lefthook runs on pre-commit into a silent mutation.
  # `bin/check` stays the both-targets formatter gate.
  defp aliases do
    [
      "deps.get": fanout("deps.get"),
      test: fanout("test"),
      coveralls: fanout("coveralls"),
      "coveralls.json": fanout("coveralls.json"),
      # `--strict` because the archive's own .credo.exs sets `strict: false`, and
      # the strict run is this repository's standard (bin/check, ci.yml,
      # .claude/08-quality-gates.md). What the ROOT run does stays whatever was
      # typed on the command line.
      credo: fanout("credo", ["--strict"]),
      dialyzer: fanout("dialyzer"),
      doctor: fanout("doctor")
    ]
  end

  defp fanout(task, extra \\ []), do: [task, &fan_out(task, extra, &1)]

  defp fan_out(task, extra, _alias_args) do
    if System.get_env(@no_fanout) in [nil, ""] do
      Enum.each(nested_targets(), &fan_out_to(&1, task, extra))
    end
  end

  # `mix cmd` aborts on a non-zero exit, so a failing archive fails the root task
  # rather than being reported and passed over.
  defp fan_out_to(dir, task, extra) do
    Mix.shell().info("==> #{dir}: mix #{Enum.join([task | extra], " ")}")
    Mix.Task.run("cmd", ["--cd", dir, "mix", task | extra])
  end

  defp nested_targets do
    "installer/*/mix.exs" |> Path.wildcard() |> Enum.map(&Path.dirname/1)
  end

  # Run "mix help deps" to learn about dependencies.
  defp deps do
    [
      {:credo, "~> 1.7", only: [:dev, :test], runtime: false},
      {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false},
      {:doctor, "~> 0.22", only: :dev, runtime: false},
      {:ex_doc, "~> 0.34", only: :dev, runtime: false},
      {:ex_machina, "~> 2.8", only: :test},
      {:excoveralls, "~> 0.18", only: :test},
      {:faker, "~> 0.19", only: :test},
      # `lefthook.yml` runs `mix git_ops.check_message` as the commit-msg hook,
      # so without this dep `lefthook install` makes every commit fail on a
      # missing task. `~> 2.12` and not the `~> 2.6` the rulebook used to
      # document: 2.11.4 fixed UTF-8 commit-message parsing, and this repo
      # writes em dashes in commit bodies routinely.
      {:git_ops, "~> 2.12", only: :dev, runtime: false}
    ]
  end

  # Vendored source lives under `lib/`, which hex ships by default -- that is a
  # side benefit of the move, not the reason for it.
  # There is no exclude form in hex -- `files:` is an allowlist, and hex's own
  # default would ship `priv` WHOLE -- so `priv` is enumerated. `priv/meta/**`
  # and `priv/baselines.exs` are deliberately absent: the three tasks that read
  # them build a CWD-relative "priv/meta" path, which in a consuming project
  # resolves against THAT project's root and fails whether or not the trees
  # shipped. The baselines travel as content-addressed release archives
  # instead -- see `mix sv_ex.baseline.record`.
  #
  # `priv/boilerplate` must ship: it is the payload rendered into every
  # generated project, and `installer/sv_ex_new` carries no `priv/` at all, so
  # the archive cannot deliver it. Without it a generated project gets no
  # `.credo.exs` and the whole comment-tag gate silently never arrives.
  #
  # An entry matching NOTHING is a hard `mix hex.build` failure ("Missing
  # files: ..."), not a no-op -- which is why there is no speculative
  # `CHANGELOG*`. Add that in the commit that first writes CHANGELOG.md.
  # Adding a new priv/ payload directory means adding it HERE too.
  defp package do
    [
      licenses: ["MIT"],
      links: %{"GitHub" => @source_url},
      files: ~w(
        lib
        priv/boilerplate
        priv/templates
        mix.exs
        .formatter.exs
        .version
        README.md
        GOAL.md
        LICENSE*
      )
    ]
  end

  # The PLT lives in `_build/` and is gitignored, so a clean checkout rebuilds
  # it rather than trusting a stale one. `:mix` and `:ex_unit` are added because
  # both the scripts and the checks call into them.
  defp dialyzer do
    [
      plt_add_apps: [:eex, :mix, :ex_unit],
      flags: [:error_handling, :extra_return, :missing_return],
      ignore_warnings: ".dialyzer_ignore.exs",
      list_unused_filters: true
    ]
  end

  # Vendored modules live under `SvEx.Vendor.*` since the namespacing rewrite,
  # so a `^SvEx` prefix match would now publish them. Their API is not ours to
  # document, so the namespace is excluded explicitly.
  defp ours?(module, _metadata) do
    name = inspect(module)
    String.starts_with?(name, "SvEx.") and not String.starts_with?(name, "SvEx.Vendor.")
  end

  defp docs do
    [
      main: "readme",
      source_ref: "v#{@version}",
      filter_modules: &ours?/2,
      extras: [
        "README.md",
        "GOAL.md": [title: "Goal"]
      ],
      formatters: ["html"]
    ]
  end
end