package main

import (
	"context"
	"strings"

	"atlas9.dev/c/core"
	"atlas9.dev/c/core/dbi"
	"atlas9.dev/c/core/iam"
)

type SqliteGrantStore struct {
	db dbi.DBI
}

var _ iam.GrantStore = (*SqliteGrantStore)(nil)

func NewSqliteGrantStore(db dbi.DBI) *SqliteGrantStore {
	return &SqliteGrantStore{db: db}
}

func (s *SqliteGrantStore) Add(ctx context.Context, g iam.Grant) error {
	if err := g.RoleID.Valid(); err != nil {
		return err
	}
	_, err := s.db.Exec(ctx, `
		INSERT INTO grants (principal_id, role_id) VALUES ($1, $2)
		ON CONFLICT (principal_id, role_id) DO NOTHING
	`, g.PrincipalID, g.RoleID)
	return err
}

func (s *SqliteGrantStore) Remove(ctx context.Context, g iam.Grant) error {
	_, err := s.db.Exec(ctx, `
		DELETE FROM grants WHERE principal_id = $1 AND role_id = $2
	`, g.PrincipalID, g.RoleID)
	return err
}

func (s *SqliteGrantStore) ListAll(ctx context.Context, page core.PageReq) (core.Page[iam.Grant], error) {
	limit := page.Limit
	if limit <= 0 {
		limit = 100
	}
	rows, err := s.db.Query(ctx, `
		SELECT principal_id, role_id FROM grants
		ORDER BY principal_id, role_id LIMIT $1
	`, limit)
	if err != nil {
		return core.Page[iam.Grant]{}, err
	}
	defer rows.Close()

	var items []iam.Grant
	for rows.Next() {
		var g iam.Grant
		if err := rows.Scan(&g.PrincipalID, &g.RoleID); err != nil {
			return core.Page[iam.Grant]{}, err
		}
		items = append(items, g)
	}
	if err := rows.Err(); err != nil {
		return core.Page[iam.Grant]{}, err
	}
	return core.Page[iam.Grant]{Items: items}, nil
}

func (s *SqliteGrantStore) ListByNamespace(ctx context.Context, namespace string, page core.PageReq) (core.Page[iam.Grant], error) {
	limit := page.Limit
	if limit <= 0 {
		limit = 100
	}
	pattern := escapeLikeGrant(namespace) + ".%"
	rows, err := s.db.Query(ctx, `
		SELECT principal_id, role_id FROM grants
		WHERE role_id LIKE $1 ESCAPE '\'
		ORDER BY principal_id, role_id LIMIT $2
	`, pattern, limit)
	if err != nil {
		return core.Page[iam.Grant]{}, err
	}
	defer rows.Close()

	var items []iam.Grant
	for rows.Next() {
		var g iam.Grant
		if err := rows.Scan(&g.PrincipalID, &g.RoleID); err != nil {
			return core.Page[iam.Grant]{}, err
		}
		items = append(items, g)
	}
	if err := rows.Err(); err != nil {
		return core.Page[iam.Grant]{}, err
	}
	return core.Page[iam.Grant]{Items: items}, nil
}

func (s *SqliteGrantStore) List(ctx context.Context, principalID core.ID, page core.PageReq) (core.Page[iam.Grant], error) {
	limit := page.Limit
	if limit <= 0 {
		limit = 100
	}
	rows, err := s.db.Query(ctx, `
		SELECT principal_id, role_id
		FROM grants
		WHERE principal_id = $1
		ORDER BY role_id
		LIMIT $2
	`, principalID, limit)
	if err != nil {
		return core.Page[iam.Grant]{}, err
	}
	defer rows.Close()

	var items []iam.Grant
	for rows.Next() {
		var g iam.Grant
		if err := rows.Scan(&g.PrincipalID, &g.RoleID); err != nil {
			return core.Page[iam.Grant]{}, err
		}
		items = append(items, g)
	}
	if err := rows.Err(); err != nil {
		return core.Page[iam.Grant]{}, err
	}
	return core.Page[iam.Grant]{Items: items}, nil
}

func escapeLikeGrant(s string) string {
	s = strings.ReplaceAll(s, `\`, `\\`)
	s = strings.ReplaceAll(s, `%`, `\%`)
	s = strings.ReplaceAll(s, `_`, `\_`)
	return s
}