package sqlite

import (
	"context"
	"database/sql"
	"encoding/json"
	"errors"
	"strings"

	"cmroubao/backend-api/internal/domain"
	"cmroubao/backend-api/internal/usecase"
)

type executionResultRequestRecord struct {
	RequestHash    string
	ClaimTokenHash string
	TaskID         string
	ExecutionID    string
	ResourceID     *string
}

func (s *Store) GetExecutionEvidence(
	ctx context.Context,
	taskID string,
	evidenceID string,
) (domain.ExecutionEvidenceAsset, error) {
	return getExecutionEvidenceForTask(ctx, s.db, taskID, evidenceID)
}

func (s *Store) AppendExecutionEvents(
	ctx context.Context,
	write usecase.ExecutionResultWrite,
	events []domain.ExecutionEvent,
) (bool, error) {
	tx, err := s.db.BeginTx(ctx, nil)
	if err != nil {
		return false, repositoryFailure(err)
	}
	defer func() { _ = tx.Rollback() }()
	if replayed, err := replayExecutionResultRequest(
		ctx, tx, write,
	); err != nil || replayed {
		return replayed, err
	}
	_, _, expired, err := authorizeExecutionResult(ctx, tx, write)
	if err != nil {
		return false, err
	}
	for _, event := range events {
		_, err = tx.ExecContext(
			ctx,
			`INSERT INTO execution_events (
				id, task_id, execution_id, step, event_type, message,
				occurred_at, received_at, received_after_execution_expiry
			) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`,
			event.ID,
			write.TaskID,
			write.ExecutionID,
			event.Step,
			event.Type,
			event.Message,
			formatTimestamp(event.OccurredAt),
			formatTimestamp(write.Now),
			expired,
		)
		if err != nil {
			return false, repositoryFailure(err)
		}
	}
	if err := insertExecutionResultRequest(ctx, tx, write, nil); err != nil {
		return false, err
	}
	if err := tx.Commit(); err != nil {
		return false, repositoryFailure(err)
	}
	return false, nil
}

func (s *Store) CreateExecutionEvidence(
	ctx context.Context,
	write usecase.ExecutionResultWrite,
	candidate domain.ExecutionEvidenceAsset,
) (domain.ExecutionEvidenceAsset, bool, error) {
	tx, err := s.db.BeginTx(ctx, nil)
	if err != nil {
		return domain.ExecutionEvidenceAsset{}, false, repositoryFailure(err)
	}
	defer func() { _ = tx.Rollback() }()
	record, found, err := lookupExecutionResultRequest(ctx, tx, write)
	if err != nil {
		return domain.ExecutionEvidenceAsset{}, false, err
	}
	if found {
		if err := validateExecutionResultReplay(record, write); err != nil {
			return domain.ExecutionEvidenceAsset{}, false, err
		}
		if record.ResourceID == nil {
			return domain.ExecutionEvidenceAsset{}, false, usecase.ErrRepositoryInvariant
		}
		evidence, err := getExecutionEvidence(ctx, tx, *record.ResourceID)
		if err != nil {
			return domain.ExecutionEvidenceAsset{}, false, err
		}
		if err := tx.Commit(); err != nil {
			return domain.ExecutionEvidenceAsset{}, false, repositoryFailure(err)
		}
		return evidence, true, nil
	}
	_, _, expired, err := authorizeExecutionResult(ctx, tx, write)
	if err != nil {
		return domain.ExecutionEvidenceAsset{}, false, err
	}
	candidate.ReceivedAfterExecutionExpiry = expired
	_, err = tx.ExecContext(
		ctx,
		`INSERT INTO execution_evidence_assets (
			id, task_id, execution_id, media_type, size_bytes, sha256,
			storage_key, created_at, received_after_execution_expiry
		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`,
		candidate.ID,
		write.TaskID,
		write.ExecutionID,
		candidate.MediaType,
		candidate.SizeBytes,
		candidate.SHA256,
		candidate.StorageKey,
		formatTimestamp(candidate.CreatedAt),
		expired,
	)
	if err != nil {
		return domain.ExecutionEvidenceAsset{}, false, repositoryFailure(err)
	}
	if err := insertExecutionResultRequest(ctx, tx, write, &candidate.ID); err != nil {
		return domain.ExecutionEvidenceAsset{}, false, err
	}
	if err := tx.Commit(); err != nil {
		return domain.ExecutionEvidenceAsset{}, false, repositoryFailure(err)
	}
	return candidate, false, nil
}

func (s *Store) StoreExecutionCandidates(
	ctx context.Context,
	write usecase.ExecutionResultWrite,
	candidate domain.ExecutionCandidateBatch,
) (bool, error) {
	tx, err := s.db.BeginTx(ctx, nil)
	if err != nil {
		return false, repositoryFailure(err)
	}
	defer func() { _ = tx.Rollback() }()
	if replayed, err := replayExecutionResultRequest(ctx, tx, write); err != nil || replayed {
		return replayed, err
	}
	task, _, expired, err := authorizeExecutionResult(ctx, tx, write)
	if err != nil {
		return false, err
	}
	if usecase.TaskContentSHA256(task) != candidate.TaskContentSHA256 {
		return false, usecase.ErrTaskVersionConflict
	}
	if err := validateCandidateEvidence(ctx, tx, write, candidate.CandidatesJSON); err != nil {
		return false, err
	}
	_, err = tx.ExecContext(
		ctx,
		`INSERT INTO execution_candidate_batches (
			execution_id, task_id, task_content_sha256, execution_mode,
			search_query, provenance_json, candidates_json, recommendation_json,
			received_at, received_after_execution_expiry
		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
		write.ExecutionID,
		write.TaskID,
		candidate.TaskContentSHA256,
		candidate.ExecutionMode,
		candidate.SearchQuery,
		nullableString(candidate.ProvenanceJSON),
		candidate.CandidatesJSON,
		nullableString(candidate.RecommendationJSON),
		formatTimestamp(write.Now),
		expired,
	)
	if err != nil {
		return false, repositoryFailure(err)
	}
	if err := insertExecutionResultRequest(ctx, tx, write, nil); err != nil {
		return false, err
	}
	if err := tx.Commit(); err != nil {
		return false, repositoryFailure(err)
	}
	return false, nil
}

func (s *Store) CompleteExecution(
	ctx context.Context,
	write usecase.ExecutionResultWrite,
	outcome domain.ExecutionOutcome,
) (domain.PurchaseTask, bool, error) {
	return s.finishExecution(ctx, write, outcome, domain.TaskStatusSucceeded)
}

func (s *Store) FailExecution(
	ctx context.Context,
	write usecase.ExecutionResultWrite,
	outcome domain.ExecutionOutcome,
) (domain.PurchaseTask, bool, error) {
	return s.finishExecution(ctx, write, outcome, domain.TaskStatusFailed)
}

func (s *Store) finishExecution(
	ctx context.Context,
	write usecase.ExecutionResultWrite,
	outcome domain.ExecutionOutcome,
	terminalStatus domain.TaskStatus,
) (domain.PurchaseTask, bool, error) {
	tx, err := s.db.BeginTx(ctx, nil)
	if err != nil {
		return domain.PurchaseTask{}, false, repositoryFailure(err)
	}
	defer func() { _ = tx.Rollback() }()
	record, found, err := lookupExecutionResultRequest(ctx, tx, write)
	if err != nil {
		return domain.PurchaseTask{}, false, err
	}
	if found {
		if err := validateExecutionResultReplay(record, write); err != nil {
			return domain.PurchaseTask{}, false, err
		}
		task, err := getLifecycleTask(ctx, tx, write.TaskID)
		if err != nil {
			return domain.PurchaseTask{}, false, err
		}
		if task.Status != terminalStatus {
			return domain.PurchaseTask{}, false, usecase.ErrTaskStateConflict
		}
		if err := tx.Commit(); err != nil {
			return domain.PurchaseTask{}, false, repositoryFailure(err)
		}
		return task, true, nil
	}
	task, execution, expired, err := authorizeExecutionResult(ctx, tx, write)
	if err != nil {
		return domain.PurchaseTask{}, false, err
	}
	if task.CancelRequestedAt != nil {
		return domain.PurchaseTask{}, false, usecase.ErrTaskStateConflict
	}
	if outcome.ResultType == "COMPLETE" {
		if outcome.TaskContentSHA256 == nil ||
			*outcome.TaskContentSHA256 != usecase.TaskContentSHA256(task) {
			return domain.PurchaseTask{}, false, usecase.ErrTaskVersionConflict
		}
		if err := validateCompleteCandidate(ctx, tx, write, outcome); err != nil {
			return domain.PurchaseTask{}, false, err
		}
		if err := validateSelectedEvidence(ctx, tx, write, outcome.SelectedCandidateJSON); err != nil {
			return domain.PurchaseTask{}, false, err
		}
	} else if err := validateEvidenceIDsFromOutcome(
		ctx, tx, write, outcome.EvidenceAssetIDsJSON,
	); err != nil {
		return domain.PurchaseTask{}, false, err
	}
	_ = execution
	outcome.ReceivedAfterExecutionExpiry = expired
	_, err = tx.ExecContext(
		ctx,
		`INSERT INTO execution_outcomes (
			execution_id, task_id, result_type, execution_mode, task_content_sha256,
			outcome, operator_reason, selected_candidate_json, evidence_asset_ids_json,
			error_code, error_message, error_step, retryable, order_submitted, received_at,
			received_after_execution_expiry
		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 0, ?, ?)`,
		write.ExecutionID,
		write.TaskID,
		outcome.ResultType,
		nullableString(outcome.ExecutionMode),
		nullableString(outcome.TaskContentSHA256),
		nullableString(outcome.Outcome),
		nullableString(outcome.OperatorReason),
		nullableString(outcome.SelectedCandidateJSON),
		nullableString(outcome.EvidenceAssetIDsJSON),
		nullableString(outcome.ErrorCode),
		nullableString(outcome.ErrorMessage),
		nullableString(outcome.ErrorStep),
		nullableBool(outcome.Retryable),
		formatTimestamp(write.Now),
		expired,
	)
	if err != nil {
		return domain.PurchaseTask{}, false, repositoryFailure(err)
	}
	step := "COMPLETED"
	if terminalStatus == domain.TaskStatusFailed {
		step = "FAILED"
	}
	result, err := tx.ExecContext(
		ctx,
		`UPDATE task_executions
		SET current_step = ?,
			last_heartbeat_at = ?,
			finished_at = ?
		WHERE id = ? AND finished_at IS NULL`,
		step,
		formatTimestamp(write.Now),
		formatTimestamp(write.Now),
		write.ExecutionID,
	)
	if err != nil {
		return domain.PurchaseTask{}, false, repositoryFailure(err)
	}
	if affected, err := result.RowsAffected(); err != nil || affected != 1 {
		if err != nil {
			return domain.PurchaseTask{}, false, repositoryFailure(err)
		}
		return domain.PurchaseTask{}, false, usecase.ErrExecutionMismatch
	}
	result, err = tx.ExecContext(
		ctx,
		`UPDATE purchase_tasks
		SET status = ?,
			version = version + 1,
			claimed_by_user_id = NULL,
			claimed_by_device_id = NULL,
			claim_token_hash = NULL,
			claim_issued_at = NULL,
			claim_expires_at = NULL,
			updated_at = ?
		WHERE id = ?
			AND status IN ('RUNNING', 'WAITING_CONFIRMATION')
			AND claim_generation = ?`,
		terminalStatus,
		formatTimestamp(write.Now),
		write.TaskID,
		write.ClaimGeneration,
	)
	if err != nil {
		return domain.PurchaseTask{}, false, repositoryFailure(err)
	}
	if affected, err := result.RowsAffected(); err != nil || affected != 1 {
		if err != nil {
			return domain.PurchaseTask{}, false, repositoryFailure(err)
		}
		return domain.PurchaseTask{}, false, usecase.ErrTaskStateConflict
	}
	if err := insertExecutionResultRequest(ctx, tx, write, nil); err != nil {
		return domain.PurchaseTask{}, false, err
	}
	task, err = getLifecycleTask(ctx, tx, write.TaskID)
	if err != nil {
		return domain.PurchaseTask{}, false, err
	}
	if err := tx.Commit(); err != nil {
		return domain.PurchaseTask{}, false, repositoryFailure(err)
	}
	return task, false, nil
}

func authorizeExecutionResult(
	ctx context.Context,
	tx *sql.Tx,
	write usecase.ExecutionResultWrite,
) (domain.PurchaseTask, domain.TaskExecution, bool, error) {
	task, err := getClaimProtectedTask(ctx, tx, write.TaskID)
	if err != nil {
		return domain.PurchaseTask{}, domain.TaskExecution{}, false, err
	}
	if err := validateClaimOwner(
		task,
		write.UserID,
		write.DeviceID,
		write.ClaimGeneration,
		write.ClaimTokenHash,
	); err != nil {
		return domain.PurchaseTask{}, domain.TaskExecution{}, false, err
	}
	if !domain.CanHeartbeat(task.Status) {
		return domain.PurchaseTask{}, domain.TaskExecution{}, false, usecase.ErrTaskStateConflict
	}
	execution, err := getExecutionByID(ctx, tx, write.ExecutionID)
	if err != nil {
		return domain.PurchaseTask{}, domain.TaskExecution{}, false, err
	}
	if execution.TaskID != write.TaskID || execution.UserID != write.UserID ||
		execution.DeviceID != write.DeviceID ||
		execution.ClaimGeneration != write.ClaimGeneration || execution.FinishedAt != nil {
		return domain.PurchaseTask{}, domain.TaskExecution{}, false, usecase.ErrExecutionMismatch
	}
	expired := task.ClaimExpiresAt == nil || !task.ClaimExpiresAt.After(write.Now)
	return task, execution, expired, nil
}

func replayExecutionResultRequest(
	ctx context.Context,
	tx *sql.Tx,
	write usecase.ExecutionResultWrite,
) (bool, error) {
	record, found, err := lookupExecutionResultRequest(ctx, tx, write)
	if err != nil || !found {
		return false, err
	}
	if err := validateExecutionResultReplay(record, write); err != nil {
		return false, err
	}
	if err := tx.Commit(); err != nil {
		return false, repositoryFailure(err)
	}
	return true, nil
}

func lookupExecutionResultRequest(
	ctx context.Context,
	tx *sql.Tx,
	write usecase.ExecutionResultWrite,
) (executionResultRequestRecord, bool, error) {
	var record executionResultRequestRecord
	var resourceID sql.NullString
	err := tx.QueryRowContext(
		ctx,
		`SELECT request_sha256, claim_token_sha256, task_id, execution_id, resource_id
		FROM execution_result_requests
		WHERE user_id = ? AND device_id = ? AND operation = ? AND idempotency_key = ?`,
		write.UserID,
		write.DeviceID,
		write.Operation,
		write.IdempotencyKey,
	).Scan(
		&record.RequestHash,
		&record.ClaimTokenHash,
		&record.TaskID,
		&record.ExecutionID,
		&resourceID,
	)
	if errors.Is(err, sql.ErrNoRows) {
		return executionResultRequestRecord{}, false, nil
	}
	if err != nil {
		return executionResultRequestRecord{}, false, repositoryFailure(err)
	}
	if resourceID.Valid {
		record.ResourceID = &resourceID.String
	}
	return record, true, nil
}

func validateExecutionResultReplay(
	record executionResultRequestRecord,
	write usecase.ExecutionResultWrite,
) error {
	if record.RequestHash != write.RequestHash ||
		record.ClaimTokenHash != write.ClaimTokenHash ||
		record.TaskID != write.TaskID || record.ExecutionID != write.ExecutionID {
		return usecase.ErrIdempotencyConflict
	}
	return nil
}

func insertExecutionResultRequest(
	ctx context.Context,
	tx *sql.Tx,
	write usecase.ExecutionResultWrite,
	resourceID *string,
) error {
	_, err := tx.ExecContext(
		ctx,
		`INSERT INTO execution_result_requests (
			user_id, device_id, operation, idempotency_key, request_sha256,
			claim_token_sha256, task_id, execution_id, resource_id, created_at
		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
		write.UserID,
		write.DeviceID,
		write.Operation,
		write.IdempotencyKey,
		write.RequestHash,
		write.ClaimTokenHash,
		write.TaskID,
		write.ExecutionID,
		nullableString(resourceID),
		formatTimestamp(write.Now),
	)
	if err != nil {
		return repositoryFailure(err)
	}
	return nil
}

func getExecutionEvidence(
	ctx context.Context,
	queryer queryRower,
	evidenceID string,
) (domain.ExecutionEvidenceAsset, error) {
	var evidence domain.ExecutionEvidenceAsset
	var createdAt string
	var receivedAfter bool
	err := queryer.QueryRowContext(
		ctx,
		`SELECT id, task_id, execution_id, media_type, size_bytes, sha256,
			storage_key, created_at, received_after_execution_expiry
		FROM execution_evidence_assets WHERE id = ?`, evidenceID,
	).Scan(
		&evidence.ID,
		&evidence.TaskID,
		&evidence.ExecutionID,
		&evidence.MediaType,
		&evidence.SizeBytes,
		&evidence.SHA256,
		&evidence.StorageKey,
		&createdAt,
		&receivedAfter,
	)
	if errors.Is(err, sql.ErrNoRows) {
		return domain.ExecutionEvidenceAsset{}, usecase.ErrRepositoryInvariant
	}
	if err != nil {
		return domain.ExecutionEvidenceAsset{}, repositoryFailure(err)
	}
	evidence.CreatedAt, err = parseTimestamp(createdAt)
	if err != nil {
		return domain.ExecutionEvidenceAsset{}, repositoryFailure(err)
	}
	evidence.ReceivedAfterExecutionExpiry = receivedAfter
	return evidence, nil
}

func getExecutionEvidenceForTask(
	ctx context.Context,
	queryer queryRower,
	taskID string,
	evidenceID string,
) (domain.ExecutionEvidenceAsset, error) {
	evidence, err := getExecutionEvidence(ctx, queryer, evidenceID)
	if err != nil {
		if errors.Is(err, usecase.ErrRepositoryInvariant) {
			return domain.ExecutionEvidenceAsset{}, usecase.ErrRepositoryNotFound
		}
		return domain.ExecutionEvidenceAsset{}, err
	}
	if evidence.TaskID != taskID {
		return domain.ExecutionEvidenceAsset{}, usecase.ErrRepositoryNotFound
	}
	return evidence, nil
}

func validateCandidateEvidence(
	ctx context.Context,
	tx *sql.Tx,
	write usecase.ExecutionResultWrite,
	candidatesJSON string,
) error {
	var candidates []struct {
		EvidenceAssetIDs []string `json:"evidence_asset_ids"`
	}
	if err := json.Unmarshal([]byte(candidatesJSON), &candidates); err != nil {
		return usecase.ErrRepositoryInvariant
	}
	for _, candidate := range candidates {
		if err := verifyExecutionEvidenceIDs(
			ctx, tx, write.TaskID, write.ExecutionID, candidate.EvidenceAssetIDs,
		); err != nil {
			return err
		}
	}
	return nil
}

func validateSelectedEvidence(
	ctx context.Context,
	tx *sql.Tx,
	write usecase.ExecutionResultWrite,
	selectedJSON *string,
) error {
	if selectedJSON == nil {
		return nil
	}
	var selected struct {
		EvidenceAssetIDs []string `json:"evidence_asset_ids"`
	}
	if err := json.Unmarshal([]byte(*selectedJSON), &selected); err != nil {
		return usecase.ErrRepositoryInvariant
	}
	return verifyExecutionEvidenceIDs(
		ctx, tx, write.TaskID, write.ExecutionID, selected.EvidenceAssetIDs,
	)
}

func validateCompleteCandidate(
	ctx context.Context,
	tx *sql.Tx,
	write usecase.ExecutionResultWrite,
	outcome domain.ExecutionOutcome,
) error {
	if outcome.Outcome == nil || *outcome.Outcome != "CANDIDATE_ACCEPTED" {
		return nil
	}
	if outcome.ExecutionMode == nil || outcome.SelectedCandidateJSON == nil {
		return usecase.ErrRepositoryInvariant
	}
	var mode string
	var candidatesJSON string
	err := tx.QueryRowContext(
		ctx,
		`SELECT execution_mode, candidates_json
		FROM execution_candidate_batches
		WHERE execution_id = ? AND task_id = ?`,
		write.ExecutionID,
		write.TaskID,
	).Scan(&mode, &candidatesJSON)
	if errors.Is(err, sql.ErrNoRows) {
		return usecase.ErrTaskStateConflict
	}
	if err != nil {
		return repositoryFailure(err)
	}
	if mode != *outcome.ExecutionMode {
		return usecase.ErrTaskStateConflict
	}
	var selected usecase.ExecutionCandidate
	var candidates []usecase.ExecutionCandidate
	if err := json.Unmarshal([]byte(*outcome.SelectedCandidateJSON), &selected); err != nil {
		return usecase.ErrRepositoryInvariant
	}
	if err := json.Unmarshal([]byte(candidatesJSON), &candidates); err != nil {
		return usecase.ErrRepositoryInvariant
	}
	for _, candidate := range candidates {
		if candidate.Ordinal != selected.Ordinal {
			continue
		}
		stored, storedErr := json.Marshal(candidate)
		selectedJSON, selectedErr := json.Marshal(selected)
		if storedErr != nil || selectedErr != nil {
			return usecase.ErrRepositoryInvariant
		}
		if string(stored) == string(selectedJSON) {
			return nil
		}
		return usecase.ErrTaskStateConflict
	}
	return usecase.ErrTaskStateConflict
}

func validateEvidenceIDsFromOutcome(
	ctx context.Context,
	tx *sql.Tx,
	write usecase.ExecutionResultWrite,
	evidenceJSON *string,
) error {
	if evidenceJSON == nil {
		return nil
	}
	var evidenceIDs []string
	if err := json.Unmarshal([]byte(*evidenceJSON), &evidenceIDs); err != nil {
		return usecase.ErrRepositoryInvariant
	}
	return verifyExecutionEvidenceIDs(
		ctx, tx, write.TaskID, write.ExecutionID, evidenceIDs,
	)
}

func verifyExecutionEvidenceIDs(
	ctx context.Context,
	tx *sql.Tx,
	taskID string,
	executionID string,
	ids []string,
) error {
	seen := map[string]struct{}{}
	for _, evidenceID := range ids {
		evidenceID = strings.TrimSpace(evidenceID)
		if _, duplicate := seen[evidenceID]; duplicate {
			return usecase.ErrTaskStateConflict
		}
		seen[evidenceID] = struct{}{}
		var exists int
		err := tx.QueryRowContext(
			ctx,
			`SELECT EXISTS (
				SELECT 1 FROM execution_evidence_assets
				WHERE id = ? AND task_id = ? AND execution_id = ?
			)`,
			evidenceID,
			taskID,
			executionID,
		).Scan(&exists)
		if err != nil {
			return repositoryFailure(err)
		}
		if exists != 1 {
			return usecase.ErrTaskStateConflict
		}
	}
	return nil
}

func getExecutionReport(
	ctx context.Context,
	queryer queryer,
	taskID string,
	executionID string,
) (*domain.ExecutionReport, error) {
	report := &domain.ExecutionReport{
		Events:         make([]domain.ExecutionEvent, 0),
		EvidenceAssets: make([]domain.ExecutionEvidenceAsset, 0),
	}
	events, err := queryer.QueryContext(
		ctx,
		`SELECT id, task_id, execution_id, step, event_type, message,
			occurred_at, received_at, received_after_execution_expiry
		FROM execution_events
		WHERE task_id = ? AND execution_id = ?
		ORDER BY occurred_at ASC, id ASC`,
		taskID,
		executionID,
	)
	if err != nil {
		return nil, repositoryFailure(err)
	}
	defer events.Close()
	for events.Next() {
		var event domain.ExecutionEvent
		var occurredAt, receivedAt string
		if err := events.Scan(
			&event.ID,
			&event.TaskID,
			&event.ExecutionID,
			&event.Step,
			&event.Type,
			&event.Message,
			&occurredAt,
			&receivedAt,
			&event.ReceivedAfterExecutionExpiry,
		); err != nil {
			return nil, repositoryFailure(err)
		}
		var parseErr error
		event.OccurredAt, parseErr = parseTimestamp(occurredAt)
		if parseErr == nil {
			event.ReceivedAt, parseErr = parseTimestamp(receivedAt)
		}
		if parseErr != nil {
			return nil, repositoryFailure(parseErr)
		}
		report.Events = append(report.Events, event)
	}
	if err := events.Err(); err != nil {
		return nil, repositoryFailure(err)
	}
	evidenceRows, err := queryer.QueryContext(
		ctx,
		`SELECT id, task_id, execution_id, media_type, size_bytes, sha256,
			storage_key, created_at, received_after_execution_expiry
		FROM execution_evidence_assets
		WHERE task_id = ? AND execution_id = ?
		ORDER BY created_at ASC, id ASC`,
		taskID,
		executionID,
	)
	if err != nil {
		return nil, repositoryFailure(err)
	}
	defer evidenceRows.Close()
	for evidenceRows.Next() {
		var evidence domain.ExecutionEvidenceAsset
		var createdAt string
		if err := evidenceRows.Scan(
			&evidence.ID,
			&evidence.TaskID,
			&evidence.ExecutionID,
			&evidence.MediaType,
			&evidence.SizeBytes,
			&evidence.SHA256,
			&evidence.StorageKey,
			&createdAt,
			&evidence.ReceivedAfterExecutionExpiry,
		); err != nil {
			return nil, repositoryFailure(err)
		}
		parsed, err := parseTimestamp(createdAt)
		if err != nil {
			return nil, repositoryFailure(err)
		}
		evidence.CreatedAt = parsed
		report.EvidenceAssets = append(report.EvidenceAssets, evidence)
	}
	if err := evidenceRows.Err(); err != nil {
		return nil, repositoryFailure(err)
	}
	var batch domain.ExecutionCandidateBatch
	var provenance, recommendation sql.NullString
	var receivedAt string
	err = queryer.QueryRowContext(
		ctx,
		`SELECT task_id, execution_id, task_content_sha256, execution_mode,
			search_query, provenance_json, candidates_json, recommendation_json,
			received_at, received_after_execution_expiry
		FROM execution_candidate_batches
		WHERE task_id = ? AND execution_id = ?`,
		taskID,
		executionID,
	).Scan(
		&batch.TaskID,
		&batch.ExecutionID,
		&batch.TaskContentSHA256,
		&batch.ExecutionMode,
		&batch.SearchQuery,
		&provenance,
		&batch.CandidatesJSON,
		&recommendation,
		&receivedAt,
		&batch.ReceivedAfterExecutionExpiry,
	)
	if err == nil {
		if provenance.Valid {
			batch.ProvenanceJSON = &provenance.String
		}
		if recommendation.Valid {
			batch.RecommendationJSON = &recommendation.String
		}
		batch.ReceivedAt, err = parseTimestamp(receivedAt)
		if err != nil {
			return nil, repositoryFailure(err)
		}
		report.CandidateBatch = &batch
	} else if !errors.Is(err, sql.ErrNoRows) {
		return nil, repositoryFailure(err)
	}
	var outcome domain.ExecutionOutcome
	var mode, hash, result, reason, selected, evidenceIDs, code, message, step sql.NullString
	var retryable sql.NullBool
	var outcomeReceivedAt string
	err = queryer.QueryRowContext(
		ctx,
		`SELECT task_id, execution_id, result_type, execution_mode,
			task_content_sha256, outcome, operator_reason, selected_candidate_json,
			evidence_asset_ids_json, error_code, error_message, error_step, retryable, order_submitted,
			received_at, received_after_execution_expiry
		FROM execution_outcomes
		WHERE task_id = ? AND execution_id = ?`,
		taskID,
		executionID,
	).Scan(
		&outcome.TaskID,
		&outcome.ExecutionID,
		&outcome.ResultType,
		&mode,
		&hash,
		&result,
		&reason,
		&selected,
		&evidenceIDs,
		&code,
		&message,
		&step,
		&retryable,
		&outcome.OrderSubmitted,
		&outcomeReceivedAt,
		&outcome.ReceivedAfterExecutionExpiry,
	)
	if err == nil {
		outcome.ExecutionMode = nullableStringFromSQL(mode)
		outcome.TaskContentSHA256 = nullableStringFromSQL(hash)
		outcome.Outcome = nullableStringFromSQL(result)
		outcome.OperatorReason = nullableStringFromSQL(reason)
		outcome.SelectedCandidateJSON = nullableStringFromSQL(selected)
		outcome.EvidenceAssetIDsJSON = nullableStringFromSQL(evidenceIDs)
		outcome.ErrorCode = nullableStringFromSQL(code)
		outcome.ErrorMessage = nullableStringFromSQL(message)
		outcome.ErrorStep = nullableStringFromSQL(step)
		if retryable.Valid {
			outcome.Retryable = &retryable.Bool
		}
		outcome.ReceivedAt, err = parseTimestamp(outcomeReceivedAt)
		if err != nil {
			return nil, repositoryFailure(err)
		}
		report.Outcome = &outcome
	} else if !errors.Is(err, sql.ErrNoRows) {
		return nil, repositoryFailure(err)
	}
	return report, nil
}

func nullableStringFromSQL(value sql.NullString) *string {
	if !value.Valid {
		return nil
	}
	return &value.String
}

var _ usecase.ExecutionResultRepository = (*Store)(nil)