package worker

import (
	"context"
	"fmt"
	"log/slog"
	"strings"
	"time"

	"github.com/TopherMayor/unified-media-manager/internal/config"
	"github.com/TopherMayor/unified-media-manager/internal/db"
)

type CleanupWorker struct {
	database *db.DB
	cfg      *config.Config
}

func NewCleanupWorker(database *db.DB, cfg *config.Config) *CleanupWorker {
	return &CleanupWorker{
		database: database,
		cfg:      cfg,
	}
}

func (w *CleanupWorker) Name() string {
	return "cleanup"
}

func (w *CleanupWorker) CronExpr() string {
	return w.cfg.WorkerCleanupInterval
}

func (w *CleanupWorker) Run(ctx context.Context) error {
	ctx, cancel := context.WithTimeout(ctx, 30*time.Second)
	defer cancel()

	partitionsDropped := 0

	rows, err := w.database.Pool.Query(ctx,
		`SELECT inhrelid::regclass::text FROM pg_inherits
		 JOIN pg_class ON (inhrelid = oid)
		 WHERE inhparent = 'download_history'::regclass`)
	if err != nil {
		return fmt.Errorf("query download_history partitions: %w", err)
	}
	defer rows.Close()

	cutoff := time.Now().AddDate(0, 0, -90)
	for rows.Next() {
		var partName string
		if err := rows.Scan(&partName); err != nil {
			slog.Error("failed to scan partition name", "error", err)
			continue
		}

		partLower := strings.ToLower(partName)
		if strings.HasPrefix(partLower, "download_history_") {
			dateStr := strings.TrimPrefix(partLower, "download_history_")
			partTime, err := time.Parse("2006_01_02", dateStr)
			if err != nil {
				continue
			}
			if partTime.Before(cutoff) {
				_, err := w.database.Pool.Exec(ctx, fmt.Sprintf("DROP TABLE IF EXISTS %s", partName))
				if err != nil {
					slog.Error("failed to drop partition", "partition", partName, "error", err)
					continue
				}
				partitionsDropped++
			}
		}
	}

	tag, err := w.database.Pool.Exec(ctx,
		"DELETE FROM task_executions WHERE started_at < NOW() - INTERVAL '7 days'")
	if err != nil {
		slog.Error("failed to clean old task executions", "error", err)
	}
	executionsCleaned := tag.RowsAffected()

	slog.Info("cleanup completed",
		"partitions_dropped", partitionsDropped,
		"executions_cleaned", executionsCleaned)

	return nil
}