package checkpoint

import (
	"encoding/base64"
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
	coreworkspace "gitea.maximumdirect.net/eric/notarius/internal/core/workspace"
	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
)

func TestWorkspaceRecorderWritesSuccessfulCheckpointFiles(t *testing.T) {
	root := t.TempDir()
	recorder := newTestRecorder(t, root)
	doc := &source.SourceDocument{
		ID:     "source-1",
		Kind:   "document",
		Format: "text/plain",
		Digest: "sha256:source",
		Units:  []source.SourceUnit{{ID: 1, Kind: "line", Text: "hello", Ref: source.SourceRef{SourceID: "source-1", StartUnitID: 1, EndUnitID: 1}}},
	}
	chunks := []contracts.SourceChunk{
		{
			ID:          "chunk-1",
			SourceID:    "source-1",
			Index:       0,
			StartUnitID: 1,
			EndUnitID:   1,
			Content:     []byte("chunk content"),
			MediaType:   "text/plain",
			Units:       doc.Units,
		},
	}

	if err := recorder.SourceRunning("seriatim"); err != nil {
		t.Fatalf("SourceRunning: %v", err)
	}
	assertManifestStatus(t, filepath.Join(root, "source", "manifest.json"), coreworkspace.StatusRunning)
	if err := recorder.SourceSucceeded("seriatim", doc); err != nil {
		t.Fatalf("SourceSucceeded: %v", err)
	}
	assertManifestStatus(t, filepath.Join(root, "source", "manifest.json"), coreworkspace.StatusSucceeded)
	if _, err := os.Stat(filepath.Join(root, "source", "source-document.json")); err != nil {
		t.Fatalf("expected source checkpoint payload: %v", err)
	}

	if err := recorder.ChunkRunning("generic", doc.Digest); err != nil {
		t.Fatalf("ChunkRunning: %v", err)
	}
	if err := recorder.ChunkSucceeded("generic", doc.Digest, chunks, nil); err != nil {
		t.Fatalf("ChunkSucceeded: %v", err)
	}
	assertManifestStatus(t, filepath.Join(root, "chunk", "manifest.json"), coreworkspace.StatusSucceeded)
	var chunkPayload struct {
		Chunks []struct {
			Content struct {
				ContentBase64 string `json:"content_base64"`
				ContentDigest string `json:"content_digest"`
			} `json:"content"`
		} `json:"chunks"`
	}
	readJSON(t, filepath.Join(root, "chunk", "chunks.json"), &chunkPayload)
	if len(chunkPayload.Chunks) != 1 {
		t.Fatalf("checkpoint chunks = %#v, want one", chunkPayload.Chunks)
	}
	decoded, err := base64.StdEncoding.DecodeString(chunkPayload.Chunks[0].Content.ContentBase64)
	if err != nil {
		t.Fatalf("decode chunk content: %v", err)
	}
	if string(decoded) != "chunk content" {
		t.Fatalf("chunk content = %q, want original content", decoded)
	}
	if got, want := chunkPayload.Chunks[0].Content.ContentDigest, contentDigest([]byte("chunk content")); got != want {
		t.Fatalf("content digest = %q, want %q", got, want)
	}
}

func TestWorkspaceLoaderReusesSuccessfulCheckpointFiles(t *testing.T) {
	root := t.TempDir()
	recorder := newTestRecorder(t, root)
	loader := &WorkspaceLoader{root: root}
	doc := &source.SourceDocument{
		ID:     "source-1",
		Kind:   "document",
		Format: "text/plain",
		Digest: "sha256:source",
		Units:  []source.SourceUnit{{ID: 1, Kind: "line", Text: "hello", Ref: source.SourceRef{SourceID: "source-1", StartUnitID: 1, EndUnitID: 1}}},
	}
	chunks := []contracts.SourceChunk{
		{
			ID:          "chunk-1",
			SourceID:    "source-1",
			Index:       0,
			StartUnitID: 1,
			EndUnitID:   1,
			Content:     []byte("chunk content"),
			MediaType:   "text/plain",
			Units:       doc.Units,
		},
	}
	extractOutput := contracts.ExtractOutput{
		LaneID:       "spells",
		ExtractorKey: "dnd/spells",
		SourceID:     doc.ID,
		ChunkID:      "chunk-1",
		Payload: contracts.RawPayload{
			Content:   []byte(`{"spell":"cure wounds"}`),
			MediaType: "application/json",
		},
	}
	mergeOutput := contracts.MergeOutput{
		LaneID:    "spells",
		MergerKey: "appendorder",
		SourceID:  doc.ID,
		Payload: contracts.RawPayload{
			Content:   []byte(`{"merged":true}`),
			MediaType: "application/json",
		},
	}
	normalizeOutput := contracts.NormalizeOutput{
		LaneID:        "spells",
		NormalizerKey: "noop",
		SourceID:      doc.ID,
		Payload: contracts.RawPayload{
			Content:   []byte(`{"normalized":true}`),
			MediaType: "application/json",
		},
	}

	if err := recorder.SourceSucceeded("seriatim", doc); err != nil {
		t.Fatalf("SourceSucceeded: %v", err)
	}
	if err := recorder.ChunkSucceeded("generic", doc.Digest, chunks, nil); err != nil {
		t.Fatalf("ChunkSucceeded: %v", err)
	}
	extractDeps := []pipeline.CheckpointFingerprint{{Name: "chunks", Value: "sha256:chunks"}}
	if err := recorder.ExtractSucceeded("spells", "dnd/spells", extractDeps, []contracts.ExtractOutput{extractOutput}, nil, nil); err != nil {
		t.Fatalf("ExtractSucceeded: %v", err)
	}
	mergeDeps := rawOutputDigests([]contracts.RawPayload{extractOutput.Payload})
	if err := recorder.MergeSucceeded("spells", "appendorder", mergeDeps, mergeOutput, nil); err != nil {
		t.Fatalf("MergeSucceeded: %v", err)
	}
	normalizeDeps := rawOutputDigests([]contracts.RawPayload{mergeOutput.Payload})
	if err := recorder.NormalizeSucceeded("spells", "noop", normalizeDeps, normalizeOutput, nil); err != nil {
		t.Fatalf("NormalizeSucceeded: %v", err)
	}

	sourceCheckpoint, decision := loader.Source("seriatim")
	if !decision.Reused || sourceCheckpoint.Document.ID != "source-1" {
		t.Fatalf("source decision = %#v checkpoint=%#v, want reused", decision, sourceCheckpoint)
	}
	if got, want := sourceCheckpoint.Document.Units[0].Ref, doc.Units[0].Ref; got != want {
		t.Fatalf("checkpoint source unit ref = %#v, want %#v", got, want)
	}
	chunkCheckpoint, decision := loader.Chunk("generic", doc.Digest)
	if !decision.Reused || len(chunkCheckpoint.Chunks) != 1 || string(chunkCheckpoint.Chunks[0].Content) != "chunk content" {
		t.Fatalf("chunk decision = %#v checkpoint=%#v, want reused", decision, chunkCheckpoint)
	}
	extractCheckpoint, decision := loader.Extract("spells", "dnd/spells", extractDeps)
	if !decision.Reused || len(extractCheckpoint.Outputs) != 1 || string(extractCheckpoint.Outputs[0].Payload.Content) != `{"spell":"cure wounds"}` {
		t.Fatalf("extract decision = %#v checkpoint=%#v, want reused", decision, extractCheckpoint)
	}
	mergeCheckpoint, decision := loader.Merge("spells", "appendorder", mergeDeps)
	if !decision.Reused || string(mergeCheckpoint.Output.Payload.Content) != `{"merged":true}` {
		t.Fatalf("merge decision = %#v checkpoint=%#v, want reused", decision, mergeCheckpoint)
	}
	normalizeCheckpoint, decision := loader.Normalize("spells", "noop", normalizeDeps)
	if !decision.Reused || string(normalizeCheckpoint.Output.Payload.Content) != `{"normalized":true}` {
		t.Fatalf("normalize decision = %#v checkpoint=%#v, want reused", decision, normalizeCheckpoint)
	}
}

func TestWorkspaceLoaderInvalidatesMissingCorruptAndMismatchedCheckpoints(t *testing.T) {
	t.Run("missing", func(t *testing.T) {
		loader := &WorkspaceLoader{root: t.TempDir()}
		if _, decision := loader.Source("seriatim"); decision.Reused || !strings.Contains(decision.Reason, "missing") {
			t.Fatalf("decision = %#v, want missing invalidation", decision)
		}
	})

	t.Run("dependency mismatch", func(t *testing.T) {
		root := t.TempDir()
		recorder := newTestRecorder(t, root)
		chunks := []contracts.SourceChunk{{
			ID:        "chunk-1",
			SourceID:  "source-1",
			Content:   []byte("chunk content"),
			MediaType: "text/plain",
		}}
		if err := recorder.ChunkSucceeded("generic", "sha256:source-a", chunks, nil); err != nil {
			t.Fatalf("ChunkSucceeded: %v", err)
		}
		loader := &WorkspaceLoader{root: root}
		if _, decision := loader.Chunk("generic", "sha256:source-b"); decision.Reused || !strings.Contains(decision.Reason, "dependency") {
			t.Fatalf("decision = %#v, want dependency invalidation", decision)
		}
	})

	t.Run("corrupt payload", func(t *testing.T) {
		root := t.TempDir()
		recorder := newTestRecorder(t, root)
		chunks := []contracts.SourceChunk{{
			ID:        "chunk-1",
			SourceID:  "source-1",
			Content:   []byte("chunk content"),
			MediaType: "text/plain",
		}}
		if err := recorder.ChunkSucceeded("generic", "sha256:source", chunks, nil); err != nil {
			t.Fatalf("ChunkSucceeded: %v", err)
		}
		payloadPath := filepath.Join(root, "chunk", "chunks.json")
		data := strings.ReplaceAll(string(readFile(t, payloadPath)), contentDigest([]byte("chunk content")), "sha256:bad")
		if err := os.WriteFile(payloadPath, []byte(data), 0o644); err != nil {
			t.Fatalf("corrupt chunk payload: %v", err)
		}
		loader := &WorkspaceLoader{root: root}
		if _, decision := loader.Chunk("generic", "sha256:source"); decision.Reused || !strings.Contains(decision.Reason, "invalid") {
			t.Fatalf("decision = %#v, want corrupt payload invalidation", decision)
		}
	})
}

func TestWorkspaceRecorderRecordsRejectedExtractOutputs(t *testing.T) {
	root := t.TempDir()
	recorder := newTestRecorder(t, root)
	rejected := []contracts.RejectedOutput{
		{
			Stage:         string(pipeline.StageExtract),
			LaneID:        "spells",
			ModuleKey:     "dnd/spells",
			ChunkID:       "chunk-1",
			ValidatorName: "shape",
			ReasonCode:    "invalid_shape",
			Message:       "bad shape",
		},
	}

	if err := recorder.ExtractRunning("spells", "dnd/spells", []pipeline.CheckpointFingerprint{{Name: "chunks", Value: "sha256:chunks"}}); err != nil {
		t.Fatalf("ExtractRunning: %v", err)
	}
	if err := recorder.ExtractSucceeded("spells", "dnd/spells", nil, nil, rejected, nil); err != nil {
		t.Fatalf("ExtractSucceeded: %v", err)
	}

	var manifest coreworkspace.ExtractLaneManifest
	readJSON(t, filepath.Join(root, "extract", "spells", "manifest.json"), &manifest)
	if manifest.Status != coreworkspace.StatusSucceededWithRejections || manifest.ValidationStatus != "rejected" {
		t.Fatalf("extract manifest status = %q validation=%q", manifest.Status, manifest.ValidationStatus)
	}
	if len(manifest.Rejections) != 1 || manifest.Rejections[0].Count != 1 || manifest.Rejections[0].ReasonCode != "invalid_shape" {
		t.Fatalf("rejections = %#v", manifest.Rejections)
	}
	var payload struct {
		Rejected []contracts.RejectedOutput `json:"rejected"`
	}
	readJSON(t, filepath.Join(root, "extract", "spells", "outputs.json"), &payload)
	if len(payload.Rejected) != 1 || payload.Rejected[0].ChunkID != "chunk-1" {
		t.Fatalf("checkpoint rejected payload = %#v", payload.Rejected)
	}
}

func TestWorkspaceRecorderRecordsFailedStages(t *testing.T) {
	root := t.TempDir()
	recorder := newTestRecorder(t, root)

	if err := recorder.MergeRunning("spells", "appendorder", nil); err != nil {
		t.Fatalf("MergeRunning: %v", err)
	}
	if err := recorder.MergeFailed("spells", "appendorder", nil, assertErr("merge failed")); err != nil {
		t.Fatalf("MergeFailed: %v", err)
	}

	var manifest coreworkspace.MergeLaneManifest
	readJSON(t, filepath.Join(root, "merge", "spells", "manifest.json"), &manifest)
	if manifest.Status != coreworkspace.StatusFailed {
		t.Fatalf("status = %q, want failed", manifest.Status)
	}
	if !strings.Contains(manifest.Metadata["error"], "merge failed") {
		t.Fatalf("metadata = %#v, want error", manifest.Metadata)
	}
}

func TestWorkspaceRecorderRecordsWarningOnlyValidation(t *testing.T) {
	root := t.TempDir()
	recorder := newTestRecorder(t, root)
	output := contracts.NormalizeOutput{
		LaneID:        "spells",
		NormalizerKey: "noop",
		SourceID:      "source-1",
		Payload: contracts.RawPayload{
			Content:   []byte(`{"ok":true}`),
			MediaType: "application/json",
		},
	}
	warnings := []contracts.Warning{{ReasonCode: "note", Message: "warning"}}

	if err := recorder.NormalizeSucceeded("spells", "noop", nil, output, warnings); err != nil {
		t.Fatalf("NormalizeSucceeded: %v", err)
	}

	var manifest coreworkspace.NormalizeLaneManifest
	readJSON(t, filepath.Join(root, "normalize", "spells", "manifest.json"), &manifest)
	if manifest.Status != coreworkspace.StatusSucceeded || manifest.ValidationStatus != "approved_with_warnings" {
		t.Fatalf("normalize manifest status = %q validation=%q", manifest.Status, manifest.ValidationStatus)
	}
}

func newTestRecorder(t *testing.T, root string) *WorkspaceRecorder {
	t.Helper()
	return &WorkspaceRecorder{root: root}
}

func assertManifestStatus(t *testing.T, path string, want coreworkspace.StageStatus) {
	t.Helper()
	var manifest coreworkspace.StageManifest
	readJSON(t, path, &manifest)
	if manifest.Status != want {
		t.Fatalf("%s status = %q, want %q", path, manifest.Status, want)
	}
}

func readJSON(t *testing.T, path string, out any) {
	t.Helper()
	data := readFile(t, path)
	if err := json.Unmarshal(data, out); err != nil {
		t.Fatalf("decode %q: %v", path, err)
	}
}

func readFile(t *testing.T, path string) []byte {
	t.Helper()
	data, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("read %q: %v", path, err)
	}
	return data
}

type assertErr string

func (e assertErr) Error() string { return string(e) }