package shared

import (
	"reflect"
	"strings"
	"testing"

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

func TestChunkPromptMaterial(t *testing.T) {
	chunk := &source.Chunk{
		ID:        "session-alpha:chunk:0",
		Content:   []byte(`{"units":[1,2]}`),
		MediaType: "application/json",
	}
	tests := []struct {
		name         string
		sourceInput  contracts.LLMInputMaterial
		want         contracts.LLMInputMaterial
		wantErr      string
		mutateOutput bool
	}{
		{
			name: "fallback to chunk content",
			want: contracts.NewLLMInputMaterial("source", chunk.MediaType, chunk.Content, "", ""),
		},
		{
			name:         "clone isolation",
			sourceInput:  contracts.NewLLMInputMaterial("source", chunk.MediaType, chunk.Content, "sha256:source", "file:///source.json"),
			want:         contracts.NewLLMInputMaterial("source", chunk.MediaType, chunk.Content, "sha256:source", "file:///source.json"),
			mutateOutput: true,
		},
		{
			name:        "mismatched content",
			sourceInput: contracts.NewLLMInputMaterial("source", chunk.MediaType, []byte(`{"units":[9]}`), "sha256:other", "file:///other.json"),
			wantErr:     "source input must match chunk",
		},
		{
			name: "default fields",
			sourceInput: contracts.LLMInputMaterial{
				Content:   append([]byte(nil), chunk.Content...),
				Digest:    "sha256:source",
				OriginURI: "file:///source.json",
			},
			want: contracts.LLMInputMaterial{
				Name:      "source",
				MediaType: chunk.MediaType,
				Content:   append([]byte(nil), chunk.Content...),
				Digest:    "sha256:source",
				OriginURI: "file:///source.json",
				SizeBytes: int64(len(chunk.Content)),
			},
		},
		{
			name: "preserve explicit metadata",
			sourceInput: contracts.LLMInputMaterial{
				Name:      "transcript",
				MediaType: "text/plain",
				Content:   append([]byte(nil), chunk.Content...),
				Digest:    "sha256:explicit",
				OriginURI: "file:///explicit.txt",
				SizeBytes: 42,
			},
			want: contracts.LLMInputMaterial{
				Name:      "transcript",
				MediaType: "text/plain",
				Content:   append([]byte(nil), chunk.Content...),
				Digest:    "sha256:explicit",
				OriginURI: "file:///explicit.txt",
				SizeBytes: 42,
			},
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			req := contracts.TypedExtractionRequest{Chunk: chunk, SourceInput: test.sourceInput}
			got, err := ChunkPromptMaterial(req)
			if test.wantErr != "" {
				if err == nil || !strings.Contains(err.Error(), test.wantErr) {
					t.Fatalf("ChunkPromptMaterial() error = %v, want %q", err, test.wantErr)
				}
				return
			}
			if err != nil {
				t.Fatalf("ChunkPromptMaterial() error = %v, want nil", err)
			}
			if !reflect.DeepEqual(got, test.want) {
				t.Fatalf("ChunkPromptMaterial() = %#v, want %#v", got, test.want)
			}
			if test.mutateOutput {
				got.Content[0] = 'x'
				if string(test.sourceInput.Content) != string(chunk.Content) {
					t.Fatalf("ChunkPromptMaterial() output shares content with source input")
				}
			}
		})
	}
}