require_relative "test_helper"
require "maptool/pmtiles_builder"
require "tmpdir"
require "fileutils"

# Network calls (the protomaps build index, individual Terrarium tile
# fetches) are never exercised here — same "keep this offline/deterministic"
# reasoning test_helper.rb already gives for /api/plugins staying off the
# real Overpass API — build_offline/build_terrain take fetch_build_url/
# fetch_tile precisely so tests can swap those out. A fake `pmtiles` CLI
# (PMTILES_BIN) stands in for the real go-pmtiles binary.
class PmtilesBuilderTest < Minitest::Test
  def setup
    @data_dir = Dir.mktmpdir("maptool-pmtiles-test-data")
    @bin_dir = Dir.mktmpdir("maptool-pmtiles-test-bin")

    # $3 is the output path either way: `extract SOURCE OUTPUT --bbox=...
    # --maxzoom=...` and `convert INPUT OUTPUT` both put it 3rd, even though
    # it's not the *last* arg in the extract case (the --flags follow it).
    @pmtiles_ok = File.join(@bin_dir, "pmtiles-ok")
    File.write(@pmtiles_ok, "#!/bin/sh\necho fake > \"$3\"\n")
    File.chmod(0o755, @pmtiles_ok)

    @pmtiles_fail = File.join(@bin_dir, "pmtiles-fail")
    File.write(@pmtiles_fail, "#!/bin/sh\necho 'boom' >&2\nexit 1\n")
    File.chmod(0o755, @pmtiles_fail)

    @original_pmtiles_bin = ENV["PMTILES_BIN"]
    Maptool::PmtilesBuilder.reset!
  end

  def teardown
    FileUtils.remove_entry(@data_dir)
    FileUtils.remove_entry(@bin_dir)
    ENV["PMTILES_BIN"] = @original_pmtiles_bin
    Maptool::PmtilesBuilder.reset!
  end

  def test_offline_and_terrain_status_start_idle
    assert_equal({ state: "idle" }, Maptool::PmtilesBuilder.offline_status)
    assert_equal({ state: "idle" }, Maptool::PmtilesBuilder.terrain_status)
  end

  def test_build_offline_writes_the_file_and_reports_done
    ENV["PMTILES_BIN"] = @pmtiles_ok
    thread = Maptool::PmtilesBuilder.build_offline(
      [1, 2, 3, 4],
      data_dir: @data_dir,
      fetch_build_url: -> { "https://example.com/fake.pmtiles" },
    )
    thread.join

    assert_path_exists File.join(@data_dir, "offline.pmtiles")
    refute_path_exists File.join(@data_dir, "offline.pmtiles.tmp")
    assert_equal "done", Maptool::PmtilesBuilder.offline_status[:state]
  end

  def test_build_offline_reports_an_error_status_on_non_zero_exit
    ENV["PMTILES_BIN"] = @pmtiles_fail
    thread = Maptool::PmtilesBuilder.build_offline(
      [1, 2, 3, 4],
      data_dir: @data_dir,
      fetch_build_url: -> { "https://example.com/fake.pmtiles" },
    )
    thread.join

    refute_path_exists File.join(@data_dir, "offline.pmtiles")
    status = Maptool::PmtilesBuilder.offline_status
    assert_equal "error", status[:state]
    assert_match(/exited with status/, status[:message])
  end

  def test_build_offline_reports_a_clear_error_when_the_binary_is_missing
    ENV["PMTILES_BIN"] = File.join(@bin_dir, "does-not-exist")
    thread = Maptool::PmtilesBuilder.build_offline(
      [1, 2, 3, 4],
      data_dir: @data_dir,
      fetch_build_url: -> { "https://example.com/fake.pmtiles" },
    )
    thread.join

    status = Maptool::PmtilesBuilder.offline_status
    assert_equal "error", status[:state]
    assert_match(/go-pmtiles installed/, status[:message])
  end

  # fetch_build_url blocks on a Queue so the build is deterministically
  # still "running" when the second call happens, rather than racing a real
  # one to see which state wins.
  def test_build_offline_raises_when_one_is_already_running
    ENV["PMTILES_BIN"] = @pmtiles_ok
    gate = Queue.new
    thread = Maptool::PmtilesBuilder.build_offline([1, 2, 3, 4], data_dir: @data_dir, fetch_build_url: -> { gate.pop })

    assert_raises(Maptool::PmtilesBuilder::BuildError) do
      Maptool::PmtilesBuilder.build_offline([1, 2, 3, 4], data_dir: @data_dir, fetch_build_url: -> { "unused" })
    end
  ensure
    gate.push("https://example.com/fake.pmtiles")
    thread&.join
  end

  # A tiny real-world bbox (a few blocks of central Bratislava) keeps the
  # z0..15 tile_range small at every zoom level, so this stays fast even
  # though it iterates all 16 levels.
  def test_build_terrain_packs_fetched_tiles_and_converts
    ENV["PMTILES_BIN"] = @pmtiles_ok
    thread = Maptool::PmtilesBuilder.build_terrain(
      [48.140, 17.100, 48.141, 17.101],
      data_dir: @data_dir,
      fetch_tile: ->(_z, _x, _y) { "not a real png, write_terrarium_mbtiles just stores opaque bytes" },
    )
    thread.join

    assert_path_exists File.join(@data_dir, "terrain.pmtiles")
    status = Maptool::PmtilesBuilder.terrain_status
    assert_equal "done", status[:state]
    assert_operator status[:tiles_total], :>, 0
    assert_equal status[:tiles_total], status[:tiles_done]
  end

  # Every fetch_tile call blocks on a gate until explicitly told not to —
  # with CONCURRENT_TILE_FETCHES workers pulling from a shared queue, that
  # holds the whole pool at "in flight, none finished yet" deterministically
  # (a big enough bbox that z0..15 yields far more tiles than worker slots,
  # so most of the job is still queued up behind the blocked pool).
  def test_build_terrain_reports_progress_while_running
    ENV["PMTILES_BIN"] = @pmtiles_ok
    concurrency = Maptool::PmtilesBuilder::CONCURRENT_TILE_FETCHES
    gate = Queue.new
    unblocked = false
    fetch_tile = lambda do |_z, _x, _y|
      gate.pop unless unblocked
      "bytes"
    end
    thread = Maptool::PmtilesBuilder.build_terrain([47.5, 16.5, 48.5, 17.5], data_dir: @data_dir, fetch_tile: fetch_tile)

    # Let exactly one batch through (fills every worker's first call) then
    # check before releasing the rest — done should be capped at the pool
    # size, nowhere near the real total.
    concurrency.times { gate.push(nil) }
    sleep 0.05
    status = Maptool::PmtilesBuilder.terrain_status
    assert_equal "running", status[:state]
    assert_operator status[:tiles_total], :>, concurrency
    assert_operator status[:tiles_done], :<, status[:tiles_total]
  ensure
    unblocked = true
    concurrency.times { gate.push(nil) } # release whatever's still blocked in an in-progress gate.pop
    thread&.join
  end

  def test_build_terrain_still_succeeds_when_some_tiles_are_missing
    ENV["PMTILES_BIN"] = @pmtiles_ok
    thread = Maptool::PmtilesBuilder.build_terrain(
      [48.140, 17.100, 48.141, 17.101],
      data_dir: @data_dir,
      fetch_tile: ->(_z, _x, _y) { nil }, # every tile "missing" — should skip, not fail, the same way HillshadeControl's own source tolerates gaps
    )
    thread.join

    assert_equal "done", Maptool::PmtilesBuilder.terrain_status[:state]
  end
end