package store

import (
	"context"
	"fmt"
	"time"
)

// Finding ist das Ergebnis einer Regel für einen Beitrag. Append-only:
// siehe Migration. ExtractionID ist optional (nil wenn ein Finding nicht
// direkt aus einer Extraktion, sondern z. B. manuell erzeugt wurde).
type Finding struct {
	ID           string
	SubmissionID string
	ExtractionID *string
	RuleID       string
	RuleVersion  int
	Severity     string
	Message      string
	CreatedAt    time.Time
}

// CreateFinding speichert ein Finding.
func (s *Store) CreateFinding(ctx context.Context, submissionID string, extractionID *string, ruleID string, ruleVersion int, severity, message string) (Finding, error) {
	var f Finding
	err := s.Pool.QueryRow(ctx, `
		INSERT INTO finding (submission_id, extraction_id, rule_id, rule_version, severity, message)
		VALUES ($1, $2, $3, $4, $5, $6)
		RETURNING id, submission_id, extraction_id, rule_id, rule_version, severity, message, created_at
	`, submissionID, extractionID, ruleID, ruleVersion, severity, message).Scan(
		&f.ID, &f.SubmissionID, &f.ExtractionID, &f.RuleID, &f.RuleVersion, &f.Severity, &f.Message, &f.CreatedAt,
	)
	if err != nil {
		return Finding{}, fmt.Errorf("store: create finding: %w", err)
	}
	return f, nil
}

// ListCurrentFindings liefert die aktuell gültigen Findings eines
// Beitrags — Zeilen, die von keiner anderen Zeile per supersedes
// ersetzt wurden (siehe Migrationskommentar zu finding.supersedes).
func (s *Store) ListCurrentFindings(ctx context.Context, submissionID string) ([]Finding, error) {
	rows, err := s.Pool.Query(ctx, `
		SELECT f.id, f.submission_id, f.extraction_id, f.rule_id, f.rule_version, f.severity, f.message, f.created_at
		FROM finding f
		WHERE f.submission_id = $1
		  AND NOT EXISTS (SELECT 1 FROM finding f2 WHERE f2.supersedes = f.id)
		ORDER BY f.created_at
	`, submissionID)
	if err != nil {
		return nil, fmt.Errorf("store: list current findings: %w", err)
	}
	defer rows.Close()

	var findings []Finding
	for rows.Next() {
		var f Finding
		if err := rows.Scan(&f.ID, &f.SubmissionID, &f.ExtractionID, &f.RuleID, &f.RuleVersion, &f.Severity, &f.Message, &f.CreatedAt); err != nil {
			return nil, fmt.Errorf("store: scan finding: %w", err)
		}
		findings = append(findings, f)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("store: list current findings: %w", err)
	}
	return findings, nil
}