package nixbuild_test

import (
	"errors"
	"os"
	"runtime"
	"slices"
	"strings"
	"testing"

	"git.gensokyo.uk/yonah/nixbuild"
)

func TestDecodeInstantiated(t *testing.T) {
	testCases := []struct {
		name    string
		out     string
		want    []string
		wantErr error
	}{
		{"bad fields", segmentPrefix + `instantiated 'config.sub-948ae97' ` + segmentSuffix, nil,
			&nixbuild.MalformedInstantiatedError{Type: nixbuild.InstantiatedBadFields}},
		{"unexpected quotes left", segmentPrefix + `instantiated 'config.sub-948ae97' -> /n'` + segmentSuffix, nil,
			&nixbuild.MalformedInstantiatedError{Type: nixbuild.InstantiatedUnexpectedQuotes}},
		{"unexpected quotes right", segmentPrefix + `instantiated 'config.sub-948ae97' -> '/n` + segmentSuffix, nil,
			&nixbuild.MalformedInstantiatedError{Type: nixbuild.InstantiatedUnexpectedQuotes}},
		{"unexpected quotes short", segmentPrefix + `instantiated 'config.sub-948ae97' -> ''` + segmentSuffix, nil,
			&nixbuild.MalformedInstantiatedError{Type: nixbuild.InstantiatedUnexpectedQuotes}},
		{"not absolute", segmentPrefix + `instantiated 'config.sub-948ae97' -> ' '` + segmentSuffix, nil,
			&nixbuild.MalformedInstantiatedError{Type: nixbuild.InstantiatedNotAbsolute}},
		{"good segment", segmentPrefix + segmentBody + segmentSuffix, []string{
			"/nix/store/3zilrlmq7r6rpzfd94mwss32b62yinj5-bootstrap-stage0-stdenv-linux.drv",
			"/nix/store/7yfwy95p6lcdpljdajs5aw10h6q0sfx0-update-autotools-gnu-config-scripts-hook.drv",
			"/nix/store/bamwxswxacs3cjdcydv0z7bj22d7g2kc-config.guess-948ae97.drv",
			"/nix/store/gyks6vvl7x0gq214ldjhi3w4rg37nh8i-zlib-1.3.1.tar.gz.drv",
			"/nix/store/nbsdqpfzh1jlpmh95s69b3iivfcvv3lh-config.sub-948ae97.drv",
			"/nix/store/ysp83x9nrks28zkblqmnc1s1kb68dr69-gnu-config-2024-01-01.drv",
		}, nil},

		{"getchoo atlas", getchooAtlasOut, getchooAtlas, nil},
		{"getchoo glados", getchooGladosOut, getchooGlados, nil},
		{"pluiedev pappardelle", pluiedevPappardelleOut, pluiedevPappardelle, nil},
	}
	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			if tc.wantErr != nil {
				w := nixbuild.Stderr
				nixbuild.Stderr = os.Stderr
				t.Cleanup(func() { nixbuild.Stderr = w })
			}

			stderr := strings.NewReader(tc.out)
			got, err := nixbuild.NewInstantiatedDecoder(stderr).Decode()
			if !errors.Is(err, tc.wantErr) {
				t.Fatalf("DecodeInstantiated: error = %v, want %v", err, tc.wantErr)
			}
			if tc.wantErr != nil {
				t.Logf("DecodeInstantiated: error = %v", err)
				return
			}
			if !slices.Equal(got, tc.want) {
				t.Errorf("DecodeInstantiated: %#v, want %#v", got, tc.want)
			}
		})
	}

	t.Run("stop early", func(t *testing.T) {
		want := []string{
			"/nix/store/gyks6vvl7x0gq214ldjhi3w4rg37nh8i-zlib-1.3.1.tar.gz.drv",
			"/nix/store/bamwxswxacs3cjdcydv0z7bj22d7g2kc-config.guess-948ae97.drv",
			"/nix/store/nbsdqpfzh1jlpmh95s69b3iivfcvv3lh-config.sub-948ae97.drv",
		}

		decoder := nixbuild.NewInstantiatedDecoder(strings.NewReader(segmentPrefix + segmentBody + segmentSuffix))
		counter := 3
		got := make([]string, 0, counter)
		for drv := range decoder.Drv() {
			got = append(got, drv)
			counter--
			if counter == 0 {
				break
			}
		}

		if !slices.Equal(got, want) {
			t.Errorf("Drv: %#v, want %#v", got, want)
		}
	})

	t.Run("errors", func(t *testing.T) {
		t.Run("bad type", func(t *testing.T) {
			badErr := errors.New("")
			if errors.Is(new(nixbuild.MalformedInstantiatedError), badErr) {
				t.Error("unexpected MalformedInstantiatedError equivalence")
			}
		})

		t.Run("nil", func(t *testing.T) {
			if errors.Is(new(nixbuild.MalformedInstantiatedError), (*nixbuild.MalformedInstantiatedError)(nil)) {
				t.Error("unexpected MalformedInstantiatedError equivalence")
			}
		})

		t.Run("unreachable", func(t *testing.T) {
			defer func() {
				wantPanic := "unreachable"
				if r := recover(); r != wantPanic {
					t.Errorf("Error: panic = %q, want %q", r, wantPanic)
				}
			}()
			_ = (&nixbuild.MalformedInstantiatedError{Type: -1}).Error()
		})
	})
}

const (
	segmentPrefix = `evaluating file '/nix/store/vdzlppvrdkz9rv14q4j02g9kpjbww2ww-source/pkgs/development/libraries/zlib/default.nix'
evaluating file '/nix/store/vdzlppvrdkz9rv14q4j02g9kpjbww2ww-source/pkgs/build-support/fetchurl/boot.nix'
performing daemon worker op: 7
instantiated 'zlib-1.3.1.tar.gz' -> '/nix/store/gyks6vvl7x0gq214ldjhi3w4rg37nh8i-zlib-1.3.1.tar.gz.drv'
source path '/nix/store/vdzlppvrdkz9rv14q4j02g9kpjbww2ww-source/pkgs/build-support/setup-hooks/update-autotools-gnu-config-scripts.sh' is uncacheable
copying '/nix/store/vdzlppvrdkz9rv14q4j02g9kpjbww2ww-source/pkgs/build-support/setup-hooks/update-autotools-gnu-config-scripts.sh' to the store...
performing daemon worker op: 7
copied '/nix/store/vdzlppvrdkz9rv14q4j02g9kpjbww2ww-source/pkgs/build-support/setup-hooks/update-autotools-gnu-config-scripts.sh' to '/nix/store/96rvfw5vlv1hwwm9sdxhdkkpjyym6p2x-update-autotools-gnu-config-scripts.sh'
copied source '/nix/store/vdzlppvrdkz9rv14q4j02g9kpjbww2ww-source/pkgs/build-support/setup-hooks/update-autotools-gnu-config-scripts.sh' -> '/nix/store/96rvfw5vlv1hwwm9sdxhdkkpjyym6p2x-update-autotools-gnu-config-scripts.sh'
evaluating file '/nix/store/vdzlppvrdkz9rv14q4j02g9kpjbww2ww-source/pkgs/by-name/gn/gnu-config/package.nix'
performing daemon worker op: 7
instantiated 'config.guess-948ae97' -> '/nix/store/bamwxswxacs3cjdcydv0z7bj22d7g2kc-config.guess-948ae97.drv'
performing daemon worker op: 7
`

	segmentBody = `instantiated 'config.sub-948ae97' -> '/nix/store/nbsdqpfzh1jlpmh95s69b3iivfcvv3lh-config.sub-948ae97.drv'`

	segmentSuffix = `
performing daemon worker op: 7
instantiated 'gnu-config-2024-01-01' -> '/nix/store/ysp83x9nrks28zkblqmnc1s1kb68dr69-gnu-config-2024-01-01.drv'
performing daemon worker op: 7
instantiated 'bootstrap-stage0-stdenv-linux' -> '/nix/store/3zilrlmq7r6rpzfd94mwss32b62yinj5-bootstrap-stage0-stdenv-linux.drv'
performing daemon worker op: 7
instantiated 'update-autotools-gnu-config-scripts-hook' -> '/nix/store/7yfwy95p6lcdpljdajs5aw10h6q0sfx0-update-autotools-gnu-config-scripts-hook.drv'
source path '/nix/store/vdzlppvrdkz9rv14q4j02g9kpjbww2ww-source/pkgs/build-support/bintools-wrapper/ld-wrapper.sh' is uncacheable
copying '/nix/store/vdzlppvrdkz9rv14q4j02g9kpjbww2ww-source/pkgs/build-support/bintools-wrapper/ld-wrapper.sh' to the store...`
)

func BenchmarkDecodeInstantiated(b *testing.B) {
	stderr := strings.NewReader(pluiedevPappardelleOut)
	var v []string
	for i := 0; i < b.N; i++ {
		v, _ = nixbuild.NewInstantiatedDecoder(stderr).Decode()
		runtime.KeepAlive(v)
	}
}

func BenchmarkDecodeInstantiatedCopy(b *testing.B) {
	stderr := strings.NewReader(getchooAtlasOut)
	var v []string
	for i := 0; i < b.N; i++ {
		v, _ = nixbuild.NewInstantiatedDecoder(stderr).Decode()
		runtime.KeepAlive(v)
	}
}