// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package testsharder

import (
	"fmt"
	"testing"

	"github.com/google/go-cmp/cmp"

	"go.fuchsia.dev/fuchsia/tools/build"
)

// Note that just printing a list of shard pointers will print a list of memory addresses,
// which would make for an unhelpful error message.
func assertEqual(t *testing.T, expected, actual []*Shard) {
	if diff := cmp.Diff(expected, actual); diff != "" {
		t.Fatalf("shards mismatch: (-want + got):\n%s", diff)
	}
}

func fullTestName(id int, os string) string {
	if os == "fuchsia" {
		return fmt.Sprintf("fuchsia-pkg://fuchsia.com/test%d", id)
	}
	return fmt.Sprintf("/path/to/test%d", id)
}

func makeTest(id int, os string) Test {
	return Test{
		Test: build.Test{
			Name:       fullTestName(id, os),
			PackageURL: fullTestName(id, "fuchsia"),
			Path:       fullTestName(id, "linux"),
			OS:         os,
		},
		Runs: 1,
	}
}

func spec(id int, envs ...build.Environment) build.TestSpec {
	return build.TestSpec{
		Test: makeTest(id, "fuchsia").Test,
		Envs: envs,
	}
}

func fuchsiaShard(env build.Environment, ids ...int) *Shard {
	return shard(env, "fuchsia", ids...)
}

func shard(env build.Environment, os string, ids ...int) *Shard {
	var tests []Test
	for _, id := range ids {
		tests = append(tests, makeTest(id, os))
	}
	return &Shard{
		Name:  environmentName(env),
		Tests: tests,
		Env:   env,
	}
}

func TestMakeShards(t *testing.T) {
	env1 := build.Environment{
		Dimensions: build.DimensionSet{DeviceType: "QEMU"},
		Tags:       []string{},
	}
	env2 := build.Environment{
		Dimensions: build.DimensionSet{DeviceType: "NUC"},
		Tags:       []string{},
	}
	env3 := build.Environment{
		Dimensions: build.DimensionSet{OS: "Linux"},
		Tags:       []string{},
	}

	basicOpts := &ShardOptions{
		Mode: Normal,
		Tags: []string{},
	}

	t.Run("environments have nonempty names", func(t *testing.T) {
		envs := []build.Environment{env1, env2, env3}
		for _, env := range envs {
			if environmentName(env) == "" {
				t.Fatalf("build.Environment\n%+v\n has an empty name", env)
			}
		}
	})

	t.Run("tests of same environment are grouped", func(t *testing.T) {
		actual := MakeShards(
			[]build.TestSpec{spec(1, env1, env2), spec(2, env1, env3), spec(3, env3)},
			basicOpts,
		)
		expected := []*Shard{fuchsiaShard(env1, 1, 2), fuchsiaShard(env2, 1), fuchsiaShard(env3, 2, 3)}
		assertEqual(t, expected, actual)
	})

	t.Run("there is no deduplication of tests", func(t *testing.T) {
		actual := MakeShards(
			[]build.TestSpec{spec(1, env1), spec(1, env1), spec(1, env1)},
			basicOpts,
		)
		expected := []*Shard{fuchsiaShard(env1, 1, 1, 1)}
		assertEqual(t, expected, actual)
	})

	// Ensure that the order of the shards is the order in which their
	// corresponding environments appear in the input. This is the simplest
	// deterministic order we can produce for the shards.
	t.Run("shards are ordered", func(t *testing.T) {
		actual := MakeShards(
			[]build.TestSpec{spec(1, env2, env3), spec(2, env1), spec(3, env3)},
			basicOpts,
		)
		expected := []*Shard{fuchsiaShard(env2, 1), fuchsiaShard(env3, 1, 3), fuchsiaShard(env1, 2)}
		assertEqual(t, expected, actual)
	})

	t.Run("tags are respected", func(t *testing.T) {
		tagger := func(env build.Environment, tags ...string) build.Environment {
			env2 := env
			env2.Tags = tags
			return env2
		}

		actual := MakeShards(
			[]build.TestSpec{
				spec(1, tagger(env1, "A")),
				spec(2, tagger(env1, "A", "B", "C")),
				spec(3, tagger(env2, "B", "C")),
				spec(4, tagger(env3, "C", "A")),
				spec(5, tagger(env3, "A", "C")),
			},
			&ShardOptions{
				Mode: Normal,
				Tags: []string{"A", "C"},
			},
		)
		expected := []*Shard{
			// "C", "A" and "A", "C" should define the same tags.
			fuchsiaShard(tagger(env3, "A", "C"), 4, 5),
		}
		assertEqual(t, expected, actual)
	})

	t.Run("different service accounts get different shards", func(t *testing.T) {
		withAcct := func(env build.Environment, acct string) build.Environment {
			env2 := env
			env2.ServiceAccount = acct
			return env2
		}

		actual := MakeShards(
			[]build.TestSpec{
				spec(1, env1),
				spec(1, withAcct(env1, "acct1")),
				spec(1, withAcct(env1, "acct2")),
			},
			basicOpts,
		)
		expected := []*Shard{
			fuchsiaShard(env1, 1),
			fuchsiaShard(withAcct(env1, "acct1"), 1),
			fuchsiaShard(withAcct(env1, "acct2"), 1),
		}
		assertEqual(t, expected, actual)
	})

	t.Run("restricted mode is respected", func(t *testing.T) {
		withAcct := func(env build.Environment, acct string) build.Environment {
			env2 := env
			env2.ServiceAccount = acct
			return env2
		}

		actual := MakeShards(
			[]build.TestSpec{
				spec(1, env1),
				spec(2, withAcct(env1, "acct1")),
				spec(3, withAcct(env1, "acct2")),
			},
			&ShardOptions{
				Mode: Restricted,
				Tags: []string{},
			},
		)
		expected := []*Shard{
			fuchsiaShard(env1, 1),
		}
		assertEqual(t, expected, actual)
	})
	t.Run("netboot envs get different shards", func(t *testing.T) {
		withNetboot := func(env build.Environment) build.Environment {
			env2 := env
			env2.Netboot = true
			return env2
		}

		actual := MakeShards(
			[]build.TestSpec{
				spec(1, env1),
				spec(1, withNetboot(env1)),
			},
			basicOpts,
		)
		expected := []*Shard{
			fuchsiaShard(env1, 1),
			fuchsiaShard(withNetboot(env1), 1),
		}
		assertEqual(t, expected, actual)
	})
}