package store

import (
	"context"
	"database/sql"
	"fmt"

	"github.com/wotra/wotra/internal/domain"
)

// EntryStore handles persistence for entries.
type EntryStore struct {
	db *sql.DB
}

func NewEntryStore(db *sql.DB) *EntryStore {
	return &EntryStore{db: db}
}

func (s *EntryStore) Create(ctx context.Context, e *domain.Entry) error {
	_, err := s.db.ExecContext(ctx,
		`INSERT INTO entries (id, start_time, end_time, auto_stopped, note, day_key, updated_at)
		 VALUES (?, ?, ?, ?, ?, ?, ?)`,
		e.ID, e.StartTime, e.EndTime, boolToInt(e.AutoStopped), e.Note, e.DayKey, e.UpdatedAt,
	)
	return err
}

func (s *EntryStore) Update(ctx context.Context, e *domain.Entry) error {
	_, err := s.db.ExecContext(ctx,
		`UPDATE entries SET start_time=?, end_time=?, auto_stopped=?, note=?, day_key=?, updated_at=?
		 WHERE id=? AND deleted_at IS NULL`,
		e.StartTime, e.EndTime, boolToInt(e.AutoStopped), e.Note, e.DayKey, e.UpdatedAt, e.ID,
	)
	return err
}

func (s *EntryStore) SoftDelete(ctx context.Context, id string, nowMs int64) error {
	_, err := s.db.ExecContext(ctx,
		`UPDATE entries SET deleted_at=?, updated_at=? WHERE id=? AND deleted_at IS NULL`,
		nowMs, nowMs, id,
	)
	return err
}

func (s *EntryStore) GetByID(ctx context.Context, id string) (*domain.Entry, error) {
	row := s.db.QueryRowContext(ctx,
		`SELECT id, start_time, end_time, auto_stopped, note, day_key, updated_at, deleted_at
		 FROM entries WHERE id=?`, id)
	return scanEntry(row)
}

func (s *EntryStore) ListByDayKey(ctx context.Context, dayKey string) ([]*domain.Entry, error) {
	rows, err := s.db.QueryContext(ctx,
		`SELECT id, start_time, end_time, auto_stopped, note, day_key, updated_at, deleted_at
		 FROM entries WHERE day_key=? AND deleted_at IS NULL ORDER BY start_time ASC`, dayKey)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	return scanEntries(rows)
}

func (s *EntryStore) ListByDateRange(ctx context.Context, fromDayKey, toDayKey string) ([]*domain.Entry, error) {
	rows, err := s.db.QueryContext(ctx,
		`SELECT id, start_time, end_time, auto_stopped, note, day_key, updated_at, deleted_at
		 FROM entries WHERE day_key >= ? AND day_key <= ? AND deleted_at IS NULL ORDER BY start_time ASC`,
		fromDayKey, toDayKey)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	return scanEntries(rows)
}

// RunningEntry returns the currently running entry (no end_time), if any.
func (s *EntryStore) RunningEntry(ctx context.Context) (*domain.Entry, error) {
	row := s.db.QueryRowContext(ctx,
		`SELECT id, start_time, end_time, auto_stopped, note, day_key, updated_at, deleted_at
		 FROM entries WHERE end_time IS NULL AND deleted_at IS NULL LIMIT 1`)
	e, err := scanEntry(row)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	return e, err
}

// RunningEntryForDay returns a running entry for a specific day, if any.
func (s *EntryStore) RunningEntryForDay(ctx context.Context, dayKey string) (*domain.Entry, error) {
	row := s.db.QueryRowContext(ctx,
		`SELECT id, start_time, end_time, auto_stopped, note, day_key, updated_at, deleted_at
		 FROM entries WHERE day_key=? AND end_time IS NULL AND deleted_at IS NULL LIMIT 1`, dayKey)
	e, err := scanEntry(row)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	return e, err
}

// StopAllRunningBefore stops all entries whose day_key < dayKey with the given end time.
// Used for the midnight auto-stop.
func (s *EntryStore) StopAllRunningBefore(ctx context.Context, dayKey string, endTimeMs int64, nowMs int64) ([]string, error) {
	rows, err := s.db.QueryContext(ctx,
		`SELECT id FROM entries WHERE end_time IS NULL AND deleted_at IS NULL AND day_key < ?`, dayKey)
	if err != nil {
		return nil, err
	}
	var ids []string
	for rows.Next() {
		var id string
		if err := rows.Scan(&id); err != nil {
			rows.Close()
			return nil, err
		}
		ids = append(ids, id)
	}
	rows.Close()
	for _, id := range ids {
		if _, err := s.db.ExecContext(ctx,
			`UPDATE entries SET end_time=?, auto_stopped=1, updated_at=? WHERE id=?`,
			endTimeMs, nowMs, id); err != nil {
			return nil, fmt.Errorf("auto-stop %s: %w", id, err)
		}
	}
	return ids, nil
}

func scanEntry(row *sql.Row) (*domain.Entry, error) {
	var e domain.Entry
	var endTime sql.NullInt64
	var deletedAt sql.NullInt64
	var autoStopped int
	err := row.Scan(&e.ID, &e.StartTime, &endTime, &autoStopped, &e.Note, &e.DayKey, &e.UpdatedAt, &deletedAt)
	if err != nil {
		return nil, err
	}
	if endTime.Valid {
		e.EndTime = &endTime.Int64
	}
	if deletedAt.Valid {
		e.DeletedAt = &deletedAt.Int64
	}
	e.AutoStopped = autoStopped != 0
	return &e, nil
}

func scanEntries(rows *sql.Rows) ([]*domain.Entry, error) {
	var result []*domain.Entry
	for rows.Next() {
		var e domain.Entry
		var endTime sql.NullInt64
		var deletedAt sql.NullInt64
		var autoStopped int
		if err := rows.Scan(&e.ID, &e.StartTime, &endTime, &autoStopped, &e.Note, &e.DayKey, &e.UpdatedAt, &deletedAt); err != nil {
			return nil, err
		}
		if endTime.Valid {
			e.EndTime = &endTime.Int64
		}
		if deletedAt.Valid {
			e.DeletedAt = &deletedAt.Int64
		}
		e.AutoStopped = autoStopped != 0
		result = append(result, &e)
	}
	return result, rows.Err()
}

func boolToInt(b bool) int {
	if b {
		return 1
	}
	return 0
}