package store

import (
	"database/sql"
	"fmt"
	"os"
	"path/filepath"
	"time"

	_ "modernc.org/sqlite"

	"ncore-hnr/internal/model"
)

type Store struct {
	db *sql.DB
}

type State struct {
	FirstSeenAt time.Time
	LastSeenAt  time.Time
}

func Open(path string) (*Store, error) {
	if dir := filepath.Dir(path); dir != "." && dir != "" {
		if err := os.MkdirAll(dir, 0o755); err != nil {
			return nil, err
		}
	}

	db, err := sql.Open("sqlite", path)
	if err != nil {
		return nil, err
	}
	store := &Store{db: db}
	if err := store.migrate(); err != nil {
		_ = db.Close()
		return nil, err
	}
	return store, nil
}

func (s *Store) Close() error {
	return s.db.Close()
}

func (s *Store) UpsertSeen(torrent model.Torrent, now time.Time) (State, error) {
	existing, err := s.state(torrent.ID)
	if err != nil {
		return State{}, err
	}

	firstSeen := now
	if !existing.FirstSeenAt.IsZero() {
		firstSeen = existing.FirstSeenAt
	}

	_, err = s.db.Exec(`
		INSERT INTO torrents (
			ncore_id, name, first_seen_at, last_seen_at, status, hnr_marked,
			uploaded_text, downloaded_text, remaining_text, ratio_text
		)
		VALUES (?, ?, ?, ?, 'active', ?, ?, ?, ?, ?)
		ON CONFLICT(ncore_id) DO UPDATE SET
			name = excluded.name,
			last_seen_at = excluded.last_seen_at,
			status = 'active',
			hnr_marked = excluded.hnr_marked,
			uploaded_text = excluded.uploaded_text,
			downloaded_text = excluded.downloaded_text,
			remaining_text = excluded.remaining_text,
			ratio_text = excluded.ratio_text
	`, torrent.ID, torrent.Name, firstSeen.Format(time.RFC3339), now.Format(time.RFC3339), boolInt(torrent.HnRMarked), torrent.Uploaded, torrent.Downloaded, torrent.Remaining, torrent.Ratio)
	if err != nil {
		return State{}, err
	}

	return State{FirstSeenAt: firstSeen, LastSeenAt: now}, nil
}

func (s *Store) MarkResolved(activeIDs map[int64]bool, now time.Time) error {
	rows, err := s.db.Query(`SELECT ncore_id FROM torrents WHERE status = 'active'`)
	if err != nil {
		return err
	}
	defer rows.Close()

	var resolved []int64
	for rows.Next() {
		var id int64
		if err := rows.Scan(&id); err != nil {
			return err
		}
		if !activeIDs[id] {
			resolved = append(resolved, id)
		}
	}
	if err := rows.Err(); err != nil {
		return err
	}

	for _, id := range resolved {
		if _, err := s.db.Exec(`UPDATE torrents SET status = 'resolved', last_resolved_at = ? WHERE ncore_id = ?`, now.Format(time.RFC3339), id); err != nil {
			return err
		}
	}
	return nil
}

func (s *Store) RecordQBit(torrent model.Torrent, qbit model.QBitTorrent, now time.Time, forceStarted bool, reannounced bool) error {
	_, err := s.db.Exec(`
		UPDATE torrents SET
			qbit_hash = ?,
			qbit_name = ?,
			qbit_state = ?,
			qbit_progress = ?,
			qbit_ratio = ?,
			qbit_uploaded = ?,
			qbit_downloaded = ?,
			qbit_last_activity = ?,
			last_action_at = CASE WHEN ? OR ? THEN ? ELSE last_action_at END
		WHERE ncore_id = ?
	`, qbit.Hash, qbit.Name, qbit.State, qbit.Progress, qbit.Ratio, qbit.Uploaded, qbit.Downloaded, qbit.LastActivity, forceStarted, reannounced, now.Format(time.RFC3339), torrent.ID)
	return err
}

func (s *Store) MarkManualNeeded(id int64, now time.Time) error {
	_, err := s.db.Exec(`
		UPDATE torrents
		SET status = 'manual_needed',
			manual_needed_at = COALESCE(manual_needed_at, ?)
		WHERE ncore_id = ?
	`, now.Format(time.RFC3339), id)
	return err
}

func (s *Store) InsertRun(summary model.RunSummary) error {
	_, err := s.db.Exec(`
		INSERT INTO runs (started_at, dry_run, total_risk, matched, unmatched, force_started, reannounced, manual_needed)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?)
	`, summary.StartedAt.Format(time.RFC3339), boolInt(summary.DryRun), summary.TotalRisk, summary.Matched, summary.Unmatched, summary.ForceStarted, summary.Reannounced, summary.ManualNeeded)
	return err
}

func (s *Store) Status() (model.StatusSnapshot, error) {
	torrents, err := s.torrentStatuses("")
	if err != nil {
		return model.StatusSnapshot{}, err
	}
	return model.StatusSnapshot{Torrents: torrents}, nil
}

func (s *Store) Stats() (model.StatsSnapshot, error) {
	counts, err := s.statusCounts()
	if err != nil {
		return model.StatsSnapshot{}, err
	}
	lastRun, err := s.lastRun()
	if err != nil {
		return model.StatsSnapshot{}, err
	}
	manualNeeded, err := s.torrentStatuses("manual_needed")
	if err != nil {
		return model.StatsSnapshot{}, err
	}

	return model.StatsSnapshot{
		Counts:       counts,
		LastRun:      lastRun,
		ManualNeeded: manualNeeded,
	}, nil
}

func (s *Store) state(id int64) (State, error) {
	var firstText string
	var lastText string
	err := s.db.QueryRow(`SELECT first_seen_at, last_seen_at FROM torrents WHERE ncore_id = ?`, id).Scan(&firstText, &lastText)
	if err == sql.ErrNoRows {
		return State{}, nil
	}
	if err != nil {
		return State{}, err
	}

	firstSeen, err := time.Parse(time.RFC3339, firstText)
	if err != nil {
		return State{}, fmt.Errorf("parse first_seen_at for %d: %w", id, err)
	}
	lastSeen, err := time.Parse(time.RFC3339, lastText)
	if err != nil {
		return State{}, fmt.Errorf("parse last_seen_at for %d: %w", id, err)
	}
	return State{FirstSeenAt: firstSeen, LastSeenAt: lastSeen}, nil
}

func (s *Store) statusCounts() ([]model.StatusCount, error) {
	rows, err := s.db.Query(`SELECT status, COUNT(*) FROM torrents GROUP BY status ORDER BY status`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var counts []model.StatusCount
	for rows.Next() {
		var count model.StatusCount
		if err := rows.Scan(&count.Status, &count.Count); err != nil {
			return nil, err
		}
		counts = append(counts, count)
	}
	return counts, rows.Err()
}

func (s *Store) lastRun() (*model.RunRecord, error) {
	var run model.RunRecord
	var dryRun int
	err := s.db.QueryRow(`
		SELECT started_at, dry_run, total_risk, matched, unmatched, force_started, reannounced, manual_needed
		FROM runs
		ORDER BY id DESC
		LIMIT 1
	`).Scan(&run.StartedAt, &dryRun, &run.TotalRisk, &run.Matched, &run.Unmatched, &run.ForceStarted, &run.Reannounced, &run.ManualNeeded)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	run.DryRun = dryRun != 0
	return &run, nil
}

func (s *Store) torrentStatuses(status string) ([]model.TorrentStatus, error) {
	query := `
		SELECT
			ncore_id,
			name,
			status,
			first_seen_at,
			last_seen_at,
			COALESCE(last_resolved_at, ''),
			hnr_marked,
			COALESCE(qbit_name, ''),
			COALESCE(qbit_state, ''),
			COALESCE(qbit_progress, 0),
			COALESCE(qbit_ratio, 0),
			COALESCE(last_action_at, ''),
			COALESCE(manual_needed_at, '')
		FROM torrents
	`
	var args []any
	if status != "" {
		query += ` WHERE status = ?`
		args = append(args, status)
	}
	query += `
		ORDER BY
			CASE status
				WHEN 'manual_needed' THEN 0
				WHEN 'active' THEN 1
				WHEN 'resolved' THEN 2
				ELSE 3
			END,
			last_seen_at DESC,
			name ASC
	`

	rows, err := s.db.Query(query, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var torrents []model.TorrentStatus
	for rows.Next() {
		var torrent model.TorrentStatus
		var hnrMarked int
		if err := rows.Scan(
			&torrent.ID,
			&torrent.Name,
			&torrent.Status,
			&torrent.FirstSeenAt,
			&torrent.LastSeenAt,
			&torrent.LastResolvedAt,
			&hnrMarked,
			&torrent.QBitName,
			&torrent.QBitState,
			&torrent.QBitProgress,
			&torrent.QBitRatio,
			&torrent.LastActionAt,
			&torrent.ManualNeededAt,
		); err != nil {
			return nil, err
		}
		torrent.HnRMarked = hnrMarked != 0
		torrents = append(torrents, torrent)
	}
	return torrents, rows.Err()
}

func (s *Store) migrate() error {
	_, err := s.db.Exec(`
		CREATE TABLE IF NOT EXISTS torrents (
			ncore_id INTEGER PRIMARY KEY,
			name TEXT NOT NULL,
			first_seen_at TEXT NOT NULL,
			last_seen_at TEXT NOT NULL,
			last_resolved_at TEXT,
			status TEXT NOT NULL,
			hnr_marked INTEGER NOT NULL DEFAULT 0,
			uploaded_text TEXT,
			downloaded_text TEXT,
			remaining_text TEXT,
			ratio_text TEXT,
			qbit_hash TEXT,
			qbit_name TEXT,
			qbit_state TEXT,
			qbit_progress REAL,
			qbit_ratio REAL,
			qbit_uploaded INTEGER,
			qbit_downloaded INTEGER,
			qbit_last_activity INTEGER,
			last_action_at TEXT,
			manual_needed_at TEXT
		);

		CREATE TABLE IF NOT EXISTS runs (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			started_at TEXT NOT NULL,
			dry_run INTEGER NOT NULL,
			total_risk INTEGER NOT NULL,
			matched INTEGER NOT NULL,
			unmatched INTEGER NOT NULL,
			force_started INTEGER NOT NULL,
			reannounced INTEGER NOT NULL,
			manual_needed INTEGER NOT NULL
		);
	`)
	return err
}

func boolInt(value bool) int {
	if value {
		return 1
	}
	return 0
}