package usecase

import (
	"context"
	"errors"
	"reflect"
	"testing"

	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
	"gitea.maximumdirect.net/eric/promptkit/internal/promptdef"
)

type inspectionPromptRepository struct {
	definition *domain.PromptDefinition
	err        error
	calls      int
	id         string
}

type promptMetadataRepository struct {
	inspection    domain.PromptInspection
	inspectionErr error
	lookupID      string
}

func (r *inspectionPromptRepository) GetPromptDefinition(
	_ context.Context,
	id string,
) (*domain.PromptDefinition, error) {
	r.calls++
	r.id = id
	if r.err != nil {
		return nil, r.err
	}
	return r.definition, nil
}

func (r *promptMetadataRepository) GetPromptDefinition(context.Context, string) (*domain.PromptDefinition, error) {
	return nil, errors.New("full prompt definition should not be requested")
}

func (r *promptMetadataRepository) GetPromptInspection(
	_ context.Context,
	id string,
) (*domain.PromptInspection, error) {
	r.lookupID = id
	inspection := r.inspection
	inspection.Inputs = append([]domain.PromptInput(nil), inspection.Inputs...)
	return &inspection, r.inspectionErr
}

func TestRunnerInspectPromptResolvesOneDefinitionWithoutExecutionCollaborators(t *testing.T) {
	definition := &domain.PromptDefinition{
		ID:             "normalized.prompt",
		Version:        "1.2.3",
		DefaultProfile: "not-resolved",
		Inputs: []domain.PromptInput{
			{Name: "document", Required: true, ContentType: "text/plain", Description: "Source document."},
			{Name: "audience", ContentType: "text/plain", Description: "Intended reader."},
		},
		Validation: domain.OutputContract{
			Format:         domain.FormatJSON,
			ValidationMode: domain.ValidationJSONSchema,
			SchemaPath:     "schemas/result.json",
			RepairAttempts: 2,
		},
	}
	repository := &inspectionPromptRepository{definition: definition}
	runner := &Runner{promptDefs: repository}

	inspection, err := runner.InspectPrompt(context.Background(), " prompt-id ")
	if err != nil {
		t.Fatalf("inspect prompt: %v", err)
	}
	wantHash, err := hashPromptDefinition(definition)
	if err != nil {
		t.Fatalf("hash prompt definition: %v", err)
	}
	if repository.calls != 1 || repository.id != " prompt-id " {
		t.Fatalf("prompt lookup=(calls=%d id=%q), want one unchanged ID lookup", repository.calls, repository.id)
	}
	if inspection.PromptID != definition.ID ||
		inspection.PromptVersion != definition.Version ||
		inspection.PromptHash != wantHash ||
		inspection.DefaultProfileID != definition.DefaultProfile ||
		!reflect.DeepEqual(inspection.Inputs, definition.Inputs) ||
		inspection.OutputContract != definition.Validation {
		t.Fatalf("inspection=%#v, want definition metadata", inspection)
	}

	inspection.Inputs[0].Name = "changed"
	second, err := runner.InspectPrompt(context.Background(), " prompt-id ")
	if err != nil {
		t.Fatalf("inspect prompt again: %v", err)
	}
	if definition.Inputs[0].Name != "document" || second.Inputs[0].Name != "document" {
		t.Fatalf("inspection input mutation escaped caller result: definition=%#v next=%#v", definition.Inputs, second.Inputs)
	}
}

func TestRunnerInspectPromptUsesOwnedMetadataWhenRepositorySupportsIt(t *testing.T) {
	repository := &promptMetadataRepository{inspection: domain.PromptInspection{
		PromptID: "captured.prompt", PromptVersion: "v2", PromptHash: "cached-prompt-hash",
		DefaultProfileID: "partial-profile",
		Inputs:           []domain.PromptInput{{Name: "document", Required: true, ContentType: "text/plain", Description: "Captured."}},
		OutputContract:   domain.OutputContract{Format: domain.FormatJSON, ValidationMode: domain.ValidationJSON},
	}}
	runner := &Runner{promptDefs: repository}
	inspection, err := runner.InspectPrompt(context.Background(), " requested-id ")
	if err != nil || repository.lookupID != " requested-id " ||
		inspection.PromptID != "captured.prompt" || inspection.PromptVersion != "v2" ||
		inspection.PromptHash != "cached-prompt-hash" || inspection.DefaultProfileID != "partial-profile" ||
		!reflect.DeepEqual(inspection.Inputs, repository.inspection.Inputs) || inspection.OutputContract != repository.inspection.OutputContract {
		t.Fatalf("metadata inspection=(%+v, %v), lookup=%q", inspection, err, repository.lookupID)
	}
	inspection.Inputs[0].Name = "caller mutation"
	inspection.OutputContract.SchemaPath = "caller mutation"
	second, err := runner.InspectPrompt(context.Background(), "requested-id")
	if err != nil || second.Inputs[0].Name != "document" || second.OutputContract.SchemaPath != "" {
		t.Fatalf("metadata inspection was not caller-owned: (%+v, %v)", second, err)
	}
}

func TestRunnerInspectPromptUsesCapturedHashWhenMetadataCapabilityIsAbsent(t *testing.T) {
	repository := &requirementInspectionPromptRepository{
		definition: &domain.PromptDefinition{
			ID: "captured.prompt", Version: "v1", Inputs: []domain.PromptInput{{Name: "document"}},
		},
	}
	inspection, err := (&Runner{promptDefs: repository}).InspectPrompt(context.Background(), " requested-id ")
	if err != nil || inspection.PromptID != "captured.prompt" || inspection.PromptVersion != "v1" ||
		inspection.PromptHash != "captured-hash" || inspection.Inputs[0].Name != "document" {
		t.Fatalf("captured-hash fallback inspection=(%+v, %v)", inspection, err)
	}
}

func TestRunnerInspectPromptClassifiesFailuresWithoutRepositoryWorkAfterCancellation(t *testing.T) {
	t.Run("blank ID", func(t *testing.T) {
		repository := &inspectionPromptRepository{}
		_, err := (&Runner{promptDefs: repository}).InspectPrompt(context.Background(), " \t ")
		if !errors.Is(err, ErrInvalidRequest) || repository.calls != 0 {
			t.Fatalf("blank inspection=(%v, calls=%d), want invalid request without lookup", err, repository.calls)
		}
	})

	t.Run("canceled context", func(t *testing.T) {
		ctx, cancel := context.WithCancel(context.Background())
		cancel()
		repository := &inspectionPromptRepository{}
		_, err := (&Runner{promptDefs: repository}).InspectPrompt(ctx, "prompt")
		if !errors.Is(err, ErrPromptLoad) || !errors.Is(err, context.Canceled) || repository.calls != 0 {
			t.Fatalf("canceled inspection=(%v, calls=%d), want prompt load and context identities without lookup", err, repository.calls)
		}
	})

	t.Run("missing prompt", func(t *testing.T) {
		repository := &inspectionPromptRepository{err: promptdef.ErrPromptDefinitionNotFound}
		_, err := (&Runner{promptDefs: repository}).InspectPrompt(context.Background(), "missing")
		if !errors.Is(err, ErrPromptLoad) || !errors.Is(err, promptdef.ErrPromptDefinitionNotFound) {
			t.Fatalf("missing prompt error=%v, want prompt load and not-found identities", err)
		}
	})

	t.Run("defensive prompt dependencies", func(t *testing.T) {
		var nilRunner *Runner
		cases := []struct {
			name   string
			runner *Runner
		}{
			{name: "nil runner", runner: nilRunner},
			{name: "nil repository", runner: &Runner{}},
			{name: "nil definition", runner: &Runner{promptDefs: &inspectionPromptRepository{}}},
		}
		for _, tc := range cases {
			t.Run(tc.name, func(t *testing.T) {
				_, err := tc.runner.InspectPrompt(context.Background(), "prompt")
				if !errors.Is(err, ErrPromptLoad) {
					t.Fatalf("inspection error=%v, want prompt load", err)
				}
			})
		}
	})
}

func TestRunnerPrepareUsesThePromptInspectionSelectionAndHash(t *testing.T) {
	definition := promptDef(domain.FormatMarkdown, domain.ValidationBasic, 0)
	repository := &fakePromptRepo{def: definition}
	runner := NewRunner(
		repository,
		&fakeExecutionProfileRepo{profiles: map[string]*domain.ExecutionProfile{"exec": defaultExecutionProfile()}},

		&fakeArtifactReader{},
		&fakeRenderer{rendered: &domain.RenderedPrompt{Messages: []domain.RenderedMessage{{Role: "user", Content: "hello"}}}},
		nil,
		nil,
		nil,
	)

	inspection, err := runner.InspectPrompt(context.Background(), definition.ID)
	if err != nil {
		t.Fatalf("inspect prompt: %v", err)
	}
	prepared, err := runner.Prepare(context.Background(), domain.RunRequest{PromptID: definition.ID, ProfileID: "exec"})
	if err != nil {
		t.Fatalf("prepare prompt: %v", err)
	}
	if inspection.PromptHash != prepared.PromptHash {
		t.Fatalf("inspection hash=%q, preparation hash=%q", inspection.PromptHash, prepared.PromptHash)
	}
}