package store

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

	"gitea.stevedudenhoeffer.com/steve/pansy/internal/domain"
)

// shareColumns lists garden_shares columns in the order scanShare expects.
const shareColumns = `id, garden_id, user_id, role, created_by, version, created_at, updated_at`

func scanShare(s scanner) (*domain.GardenShare, error) {
	var sh domain.GardenShare
	if err := s.Scan(
		&sh.ID, &sh.GardenID, &sh.UserID, &sh.Role, &sh.CreatedBy,
		&sh.Version, &sh.CreatedAt, &sh.UpdatedAt,
	); err != nil {
		return nil, err
	}
	return &sh, nil
}

// GetShareRole returns the role a user holds on a garden via a share row, and
// whether such a row exists. Owner access is NOT a share row (it's implicit via
// gardens.owner_id) — this only reports viewer/editor grants. It is the lookup
// requireGardenRole uses to consult shares.
func (d *DB) GetShareRole(ctx context.Context, gardenID, userID int64) (role string, found bool, err error) {
	err = d.sql.QueryRowContext(ctx,
		`SELECT role FROM garden_shares WHERE garden_id = ? AND user_id = ?`, gardenID, userID,
	).Scan(&role)
	if errors.Is(err, sql.ErrNoRows) {
		return "", false, nil
	}
	if err != nil {
		return "", false, fmt.Errorf("store: get share role: %w", err)
	}
	return role, true, nil
}

// ListSharesForGarden returns a garden's shares joined with each recipient's
// email and display name, for the sharing UI. Always a non-nil slice.
func (d *DB) ListSharesForGarden(ctx context.Context, gardenID int64) ([]domain.ShareWithUser, error) {
	rows, err := d.sql.QueryContext(ctx,
		`SELECT `+qualifyColumns("s", shareColumns)+`, u.email, u.display_name
		   FROM garden_shares s JOIN users u ON u.id = s.user_id
		  WHERE s.garden_id = ?
		  ORDER BY u.display_name COLLATE NOCASE, s.id`,
		gardenID,
	)
	if err != nil {
		return nil, fmt.Errorf("store: list shares: %w", err)
	}
	defer rows.Close()

	shares := []domain.ShareWithUser{}
	for rows.Next() {
		var sh domain.ShareWithUser
		if err := rows.Scan(
			&sh.ID, &sh.GardenID, &sh.UserID, &sh.Role, &sh.CreatedBy,
			&sh.Version, &sh.CreatedAt, &sh.UpdatedAt, &sh.Email, &sh.DisplayName,
		); err != nil {
			return nil, fmt.Errorf("store: scan share: %w", err)
		}
		shares = append(shares, sh)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("store: iterate shares: %w", err)
	}
	return shares, nil
}

// CreateShare inserts a share (fields validated by the service) and returns the
// stored row. A duplicate (garden_id, user_id) trips the UNIQUE index and maps to
// domain.ErrShareExists.
func (d *DB) CreateShare(ctx context.Context, sh *domain.GardenShare) (*domain.GardenShare, error) {
	created, err := scanShare(d.sql.QueryRowContext(ctx,
		`INSERT INTO garden_shares (garden_id, user_id, role, created_by)
		 VALUES (?, ?, ?, ?)
		 RETURNING `+shareColumns,
		sh.GardenID, sh.UserID, sh.Role, sh.CreatedBy,
	))
	if err != nil {
		if isUniqueViolation(err) {
			return nil, domain.ErrShareExists
		}
		return nil, fmt.Errorf("store: insert share: %w", err)
	}
	return created, nil
}

// UpdateShareRole changes a share's role, returning the updated row or
// domain.ErrNotFound if no such share exists.
func (d *DB) UpdateShareRole(ctx context.Context, gardenID, userID int64, role string) (*domain.GardenShare, error) {
	updated, err := scanShare(d.sql.QueryRowContext(ctx,
		`UPDATE garden_shares
		    SET role = ?, version = version + 1,
		        updated_at = strftime('%Y-%m-%dT%H:%M:%SZ', 'now')
		  WHERE garden_id = ? AND user_id = ?
		  RETURNING `+shareColumns,
		role, gardenID, userID,
	))
	if errors.Is(err, sql.ErrNoRows) {
		return nil, domain.ErrNotFound
	}
	if err != nil {
		return nil, fmt.Errorf("store: update share role: %w", err)
	}
	return updated, nil
}

// DeleteShare removes a share. Returns domain.ErrNotFound if no row was deleted.
func (d *DB) DeleteShare(ctx context.Context, gardenID, userID int64) error {
	res, err := d.sql.ExecContext(ctx,
		`DELETE FROM garden_shares WHERE garden_id = ? AND user_id = ?`, gardenID, userID)
	if err != nil {
		return fmt.Errorf("store: delete share: %w", err)
	}
	n, err := res.RowsAffected()
	if err != nil {
		return fmt.Errorf("store: share delete rows: %w", err)
	}
	if n == 0 {
		return domain.ErrNotFound
	}
	return nil
}