package workspace

import (
	"path/filepath"
	"strings"
	"testing"

	"gitea.maximumdirect.net/eric/notarius/internal/core/artifacts"
	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
)

func TestCheckpointIdentityIsDeterministic(t *testing.T) {
	first := mustIdentity(t, identityInput())
	second := mustIdentity(t, identityInput())

	if first.Digest != second.Digest {
		t.Fatalf("digest changed for same input: %q != %q", first.Digest, second.Digest)
	}
	if !strings.HasPrefix(first.Digest, "sha256:") {
		t.Fatalf("digest = %q, want sha256 prefix", first.Digest)
	}
}

func TestCheckpointIdentityChangesWhenInputsChange(t *testing.T) {
	base := mustIdentity(t, identityInput())
	tests := []struct {
		name   string
		mutate func(CheckpointIdentityInput) CheckpointIdentityInput
	}{
		{
			name: "pipeline digest",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.Pipeline.Digest = "sha256:pipeline-b"
				return input
			},
		},
		{
			name: "raw input digest",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.RawInputDigest = "sha256:raw-b"
				return input
			},
		},
		{
			name: "selected lanes",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.SelectedLanes = []string{"items"}
				return input
			},
		},
		{
			name: "reference digest",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.References[0].Digest = "sha256:reference-b"
				return input
			},
		},
		{
			name: "runtime override",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.RuntimeOverrides = []Fingerprint{{Name: "llm_profile", Value: "careful"}}
				return input
			},
		},
		{
			name: "provenance fingerprint",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.ProvenanceFingerprints = []Fingerprint{{Name: "prompt:dnd.spells", Value: "sha256:prompt-b"}}
				return input
			},
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			changed := mustIdentity(t, tc.mutate(identityInput()))
			if changed.Digest == base.Digest {
				t.Fatalf("digest did not change after %s mutation: %q", tc.name, changed.Digest)
			}
		})
	}
}

func TestCheckpointIdentityNormalizesOrder(t *testing.T) {
	input := identityInput()
	input.SelectedLanes = []string{"spells", "items", "spells"}
	input.RuntimeOverrides = []Fingerprint{
		{Name: "z", Value: "2"},
		{Name: "a", Value: "1"},
	}
	input.ProvenanceFingerprints = []Fingerprint{
		{Name: "schema", Value: "sha256:schema"},
		{Name: "prompt", Value: "sha256:prompt"},
	}

	identity := mustIdentity(t, input)

	if got := strings.Join(identity.SelectedLanes, ","); got != "items,spells" {
		t.Fatalf("selected lanes = %q, want sorted unique values", got)
	}
	if identity.RuntimeOverrides[0].Name != "a" || identity.ProvenanceFingerprints[0].Name != "prompt" {
		t.Fatalf("fingerprints not sorted: runtime=%+v provenance=%+v", identity.RuntimeOverrides, identity.ProvenanceFingerprints)
	}
}

func TestCheckpointIdentityPathIsFilesystemSafe(t *testing.T) {
	input := identityInput()
	input.Pipeline.ID = "campaign/main"
	input.InputKey = "seriatim/input"
	input.SourceDigest = "sha256:abcdef0123456789ffffffff"
	input.Pipeline.Digest = "sha256:1234567890abcdefeeeeeeee"
	identity := mustIdentity(t, input)

	relative, err := identity.RelativePath()
	if err != nil {
		t.Fatalf("RelativePath: %v", err)
	}
	if strings.Contains(relative, `\`) || strings.Contains(relative, "..") {
		t.Fatalf("relative path is not filesystem safe: %q", relative)
	}
	if relative != "campaign~2fmain/seriatim~2finput-abcdef0123456789/1234567890abcdef" {
		t.Fatalf("relative path = %q", relative)
	}

	root := t.TempDir()
	settings := Settings{
		CheckpointsRoot: filepath.Join(root, "checkpoints"),
		ResumeEnabled:   true,
	}
	got, err := settings.CheckpointDirectory(identity)
	if err != nil {
		t.Fatalf("CheckpointDirectory: %v", err)
	}
	want := filepath.Join(root, "checkpoints", "campaign~2fmain", "seriatim~2finput-abcdef0123456789", "1234567890abcdef")
	if got != want {
		t.Fatalf("checkpoint directory = %q, want %q", got, want)
	}
}

func TestCheckpointDirectoryDisabledReturnsEmptyPath(t *testing.T) {
	settings := Settings{CheckpointsRoot: filepath.Join(t.TempDir(), "checkpoints")}
	got, err := settings.CheckpointDirectory(mustIdentity(t, identityInput()))
	if err != nil {
		t.Fatalf("CheckpointDirectory: %v", err)
	}
	if got != "" {
		t.Fatalf("CheckpointDirectory = %q, want empty path", got)
	}
}

func TestNewCheckpointIdentityRequiresCoreInputs(t *testing.T) {
	tests := []struct {
		name   string
		mutate func(CheckpointIdentityInput) CheckpointIdentityInput
		want   string
	}{
		{
			name: "pipeline id",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.Pipeline.ID = ""
				return input
			},
			want: "pipeline id",
		},
		{
			name: "pipeline digest",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.Pipeline.Digest = ""
				return input
			},
			want: "pipeline digest",
		},
		{
			name: "input key",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.InputKey = ""
				input.Pipeline.Input.Module = ""
				return input
			},
			want: "input key",
		},
		{
			name: "input digest",
			mutate: func(input CheckpointIdentityInput) CheckpointIdentityInput {
				input.RawInputDigest = ""
				input.SourceDigest = ""
				return input
			},
			want: "raw input digest or source digest",
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			_, err := NewCheckpointIdentity(tc.mutate(identityInput()))
			if err == nil || !strings.Contains(err.Error(), tc.want) {
				t.Fatalf("expected error containing %q, got %v", tc.want, err)
			}
		})
	}
}

func identityInput() CheckpointIdentityInput {
	return CheckpointIdentityInput{
		Pipeline: pipeline.ResolvedPipeline{
			ID:     "dnd-session",
			Digest: "sha256:pipeline-a",
			Input:  pipeline.Binding("seriatim"),
			ArtifactLanes: []pipeline.ResolvedArtifactLane{
				{ID: "spells"},
				{ID: "items"},
			},
		},
		InputKey:       "seriatim",
		RawInputDigest: "sha256:raw-a",
		SelectedLanes:  []string{"spells"},
		RuntimeOverrides: []Fingerprint{
			{Name: "llm_profile", Value: "fast"},
		},
		References: []artifacts.ReferenceProvenance{
			{
				Stage:     "extract",
				LaneID:    "spells",
				SlotName:  "party",
				OriginURI: "file:///party.yml",
				Digest:    "sha256:reference-a",
			},
		},
		ProvenanceFingerprints: []Fingerprint{
			{Name: "prompt:dnd.spells", Value: "sha256:prompt-a"},
		},
	}
}

func mustIdentity(t *testing.T, input CheckpointIdentityInput) CheckpointIdentity {
	t.Helper()
	identity, err := NewCheckpointIdentity(input)
	if err != nil {
		t.Fatalf("NewCheckpointIdentity: %v", err)
	}
	return identity
}