package store

import (
	"context"
	"database/sql"

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

// SettingsStore handles persistence for settings history.
type SettingsStore struct {
	db *sql.DB
}

func NewSettingsStore(db *sql.DB) *SettingsStore {
	return &SettingsStore{db: db}
}

// Current returns the most recent settings effective on or before the given day key.
func (s *SettingsStore) Current(ctx context.Context, asOfDayKey string) (*domain.Settings, error) {
	row := s.db.QueryRowContext(ctx,
		`SELECT id, effective_from, hours_per_week, workdays_mask, timezone, created_at, updated_at
		 FROM settings_history
		 WHERE effective_from <= ?
		 ORDER BY effective_from DESC, id DESC
		 LIMIT 1`, asOfDayKey)
	return scanSettings(row)
}

// Latest returns the most recently created settings row.
func (s *SettingsStore) Latest(ctx context.Context) (*domain.Settings, error) {
	row := s.db.QueryRowContext(ctx,
		`SELECT id, effective_from, hours_per_week, workdays_mask, timezone, created_at, updated_at
		 FROM settings_history
		 ORDER BY effective_from DESC, id DESC
		 LIMIT 1`)
	return scanSettings(row)
}

// History returns all settings rows ordered by effective_from DESC.
func (s *SettingsStore) History(ctx context.Context) ([]*domain.Settings, error) {
	rows, err := s.db.QueryContext(ctx,
		`SELECT id, effective_from, hours_per_week, workdays_mask, timezone, created_at, updated_at
		 FROM settings_history ORDER BY effective_from DESC, id DESC`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var result []*domain.Settings
	for rows.Next() {
		var s domain.Settings
		if err := rows.Scan(&s.ID, &s.EffectiveFrom, &s.HoursPerWeek, &s.WorkdaysMask, &s.Timezone, &s.CreatedAt, &s.UpdatedAt); err != nil {
			return nil, err
		}
		result = append(result, &s)
	}
	return result, rows.Err()
}

// Insert inserts a new settings row.
func (s *SettingsStore) Insert(ctx context.Context, set *domain.Settings) error {
	_, err := s.db.ExecContext(ctx,
		`INSERT INTO settings_history (id, effective_from, hours_per_week, workdays_mask, timezone, created_at, updated_at)
		 VALUES (?, ?, ?, ?, ?, ?, ?)`,
		set.ID, set.EffectiveFrom, set.HoursPerWeek, set.WorkdaysMask, set.Timezone, set.CreatedAt, set.UpdatedAt)
	return err
}

// Update overwrites an existing settings row by ID.
func (s *SettingsStore) Update(ctx context.Context, set *domain.Settings) error {
	_, err := s.db.ExecContext(ctx,
		`UPDATE settings_history
		 SET effective_from=?, hours_per_week=?, workdays_mask=?, timezone=?, updated_at=?
		 WHERE id=?`,
		set.EffectiveFrom, set.HoursPerWeek, set.WorkdaysMask, set.Timezone, set.UpdatedAt, set.ID)
	return err
}

// Upsert inserts or replaces a settings row (used by sync push; last updated_at wins).
func (s *SettingsStore) Upsert(ctx context.Context, set *domain.Settings) error {
	_, err := s.db.ExecContext(ctx,
		`INSERT INTO settings_history (id, effective_from, hours_per_week, workdays_mask, timezone, created_at, updated_at)
		 VALUES (?, ?, ?, ?, ?, ?, ?)
		 ON CONFLICT(id) DO UPDATE SET
		   effective_from=excluded.effective_from,
		   hours_per_week=excluded.hours_per_week,
		   workdays_mask=excluded.workdays_mask,
		   timezone=excluded.timezone,
		   updated_at=excluded.updated_at
		 WHERE excluded.updated_at > settings_history.updated_at`,
		set.ID, set.EffectiveFrom, set.HoursPerWeek, set.WorkdaysMask, set.Timezone, set.CreatedAt, set.UpdatedAt)
	return err
}

// Delete removes a settings row by ID.
func (s *SettingsStore) Delete(ctx context.Context, id string) error {
	_, err := s.db.ExecContext(ctx, `DELETE FROM settings_history WHERE id=?`, id)
	return err
}

// Count returns the total number of settings rows.
func (s *SettingsStore) Count(ctx context.Context) (int, error) {
	var n int
	err := s.db.QueryRowContext(ctx, `SELECT COUNT(*) FROM settings_history`).Scan(&n)
	return n, err
}

// GetByID returns a single settings row by ID.
func (s *SettingsStore) GetByID(ctx context.Context, id string) (*domain.Settings, error) {
	row := s.db.QueryRowContext(ctx,
		`SELECT id, effective_from, hours_per_week, workdays_mask, timezone, created_at, updated_at
		 FROM settings_history WHERE id=?`, id)
	return scanSettings(row)
}

func scanSettings(row *sql.Row) (*domain.Settings, error) {
	var s domain.Settings
	err := row.Scan(&s.ID, &s.EffectiveFrom, &s.HoursPerWeek, &s.WorkdaysMask, &s.Timezone, &s.CreatedAt, &s.UpdatedAt)
	if err != nil {
		return nil, err
	}
	return &s, nil
}