package postgres

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

	"github.com/google/uuid"
	"github.com/kms/api-key-service/internal/domain"
	"github.com/kms/api-key-service/internal/repository"
	"github.com/lib/pq"
)

// PermissionRepository implements the PermissionRepository interface for PostgreSQL
type PermissionRepository struct {
	db repository.DatabaseProvider
}

// NewPermissionRepository creates a new PostgreSQL permission repository
func NewPermissionRepository(db repository.DatabaseProvider) repository.PermissionRepository {
	return &PermissionRepository{db: db}
}

// CreateAvailablePermission creates a new available permission
func (r *PermissionRepository) CreateAvailablePermission(ctx context.Context, permission *domain.AvailablePermission) error {
	query := `
		INSERT INTO available_permissions (
			id, scope, name, description, category, parent_scope, 
			is_system, created_by, updated_by, created_at, updated_at
		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)
	`

	db := r.db.GetDB().(*sql.DB)
	now := time.Now()

	if permission.ID == uuid.Nil {
		permission.ID = uuid.New()
	}

	_, err := db.ExecContext(ctx, query,
		permission.ID,
		permission.Scope,
		permission.Name,
		permission.Description,
		permission.Category,
		permission.ParentScope,
		permission.IsSystem,
		permission.CreatedBy,
		permission.UpdatedBy,
		now,
		now,
	)

	if err != nil {
		return fmt.Errorf("failed to create available permission: %w", err)
	}

	permission.CreatedAt = now
	permission.UpdatedAt = now

	return nil
}

// GetAvailablePermission retrieves an available permission by ID
func (r *PermissionRepository) GetAvailablePermission(ctx context.Context, permissionID uuid.UUID) (*domain.AvailablePermission, error) {
	query := `
		SELECT id, scope, name, description, category, parent_scope, 
		       is_system, created_at, created_by, updated_at, updated_by
		FROM available_permissions 
		WHERE id = $1
	`

	db := r.db.GetDB().(*sql.DB)
	row := db.QueryRowContext(ctx, query, permissionID)

	permission := &domain.AvailablePermission{}
	err := row.Scan(
		&permission.ID,
		&permission.Scope,
		&permission.Name,
		&permission.Description,
		&permission.Category,
		&permission.ParentScope,
		&permission.IsSystem,
		&permission.CreatedAt,
		&permission.CreatedBy,
		&permission.UpdatedAt,
		&permission.UpdatedBy,
	)

	if err != nil {
		if err == sql.ErrNoRows {
			return nil, fmt.Errorf("permission with ID '%s' not found", permissionID)
		}
		return nil, fmt.Errorf("failed to get available permission: %w", err)
	}

	return permission, nil
}

// GetAvailablePermissionByScope retrieves an available permission by scope
func (r *PermissionRepository) GetAvailablePermissionByScope(ctx context.Context, scope string) (*domain.AvailablePermission, error) {
	query := `
		SELECT id, scope, name, description, category, parent_scope, 
		       is_system, created_at, created_by, updated_at, updated_by
		FROM available_permissions 
		WHERE scope = $1
	`

	db := r.db.GetDB().(*sql.DB)
	row := db.QueryRowContext(ctx, query, scope)

	permission := &domain.AvailablePermission{}
	err := row.Scan(
		&permission.ID,
		&permission.Scope,
		&permission.Name,
		&permission.Description,
		&permission.Category,
		&permission.ParentScope,
		&permission.IsSystem,
		&permission.CreatedAt,
		&permission.CreatedBy,
		&permission.UpdatedAt,
		&permission.UpdatedBy,
	)

	if err != nil {
		if err == sql.ErrNoRows {
			return nil, fmt.Errorf("permission with scope '%s' not found", scope)
		}
		return nil, fmt.Errorf("failed to get available permission by scope: %w", err)
	}

	return permission, nil
}

// ListAvailablePermissions retrieves available permissions with pagination and filtering
func (r *PermissionRepository) ListAvailablePermissions(ctx context.Context, category string, includeSystem bool, limit, offset int) ([]*domain.AvailablePermission, error) {
	// TODO: Implement actual permission listing
	return []*domain.AvailablePermission{}, nil
}

// UpdateAvailablePermission updates an available permission
func (r *PermissionRepository) UpdateAvailablePermission(ctx context.Context, permissionID uuid.UUID, permission *domain.AvailablePermission) error {
	// TODO: Implement actual permission update
	return nil
}

// DeleteAvailablePermission deletes an available permission
func (r *PermissionRepository) DeleteAvailablePermission(ctx context.Context, permissionID uuid.UUID) error {
	// TODO: Implement actual permission deletion
	return nil
}

// ValidatePermissionScopes checks if all given scopes exist and are valid
func (r *PermissionRepository) ValidatePermissionScopes(ctx context.Context, scopes []string) ([]string, error) {
	if len(scopes) == 0 {
		return []string{}, nil
	}

	query := `
		SELECT scope 
		FROM available_permissions 
		WHERE scope = ANY($1)
	`

	db := r.db.GetDB().(*sql.DB)
	rows, err := db.QueryContext(ctx, query, pq.Array(scopes))
	if err != nil {
		return nil, fmt.Errorf("failed to validate permission scopes: %w", err)
	}
	defer rows.Close()

	validScopes := make(map[string]bool)
	for rows.Next() {
		var scope string
		if err := rows.Scan(&scope); err != nil {
			return nil, fmt.Errorf("failed to scan scope: %w", err)
		}
		validScopes[scope] = true
	}

	if err = rows.Err(); err != nil {
		return nil, fmt.Errorf("error iterating scopes: %w", err)
	}

	var result []string
	for _, scope := range scopes {
		if validScopes[scope] {
			result = append(result, scope)
		}
	}

	return result, nil
}

// GetPermissionHierarchy returns all parent and child permissions for given scopes
func (r *PermissionRepository) GetPermissionHierarchy(ctx context.Context, scopes []string) ([]*domain.AvailablePermission, error) {
	// TODO: Implement actual permission hierarchy retrieval
	return []*domain.AvailablePermission{}, nil
}

// GrantedPermissionRepository implements the GrantedPermissionRepository interface for PostgreSQL
type GrantedPermissionRepository struct {
	db repository.DatabaseProvider
}

// NewGrantedPermissionRepository creates a new PostgreSQL granted permission repository
func NewGrantedPermissionRepository(db repository.DatabaseProvider) repository.GrantedPermissionRepository {
	return &GrantedPermissionRepository{db: db}
}

// GrantPermissions grants multiple permissions to a token
func (r *GrantedPermissionRepository) GrantPermissions(ctx context.Context, grants []*domain.GrantedPermission) error {
	if len(grants) == 0 {
		return nil
	}

	db := r.db.GetDB().(*sql.DB)
	tx, err := db.BeginTx(ctx, nil)
	if err != nil {
		return fmt.Errorf("failed to begin transaction: %w", err)
	}
	defer tx.Rollback()

	query := `
		INSERT INTO granted_permissions (
			id, token_type, token_id, permission_id, scope, created_by, created_at
		) VALUES ($1, $2, $3, $4, $5, $6, $7)
		ON CONFLICT (token_type, token_id, permission_id) DO NOTHING
	`

	stmt, err := tx.PrepareContext(ctx, query)
	if err != nil {
		return fmt.Errorf("failed to prepare statement: %w", err)
	}
	defer stmt.Close()

	now := time.Now()
	for _, grant := range grants {
		if grant.ID == uuid.Nil {
			grant.ID = uuid.New()
		}

		_, err = stmt.ExecContext(ctx,
			grant.ID,
			string(grant.TokenType),
			grant.TokenID,
			grant.PermissionID,
			grant.Scope,
			grant.CreatedBy,
			now,
		)
		if err != nil {
			return fmt.Errorf("failed to grant permission: %w", err)
		}

		grant.CreatedAt = now
	}

	if err = tx.Commit(); err != nil {
		return fmt.Errorf("failed to commit transaction: %w", err)
	}

	return nil
}

// GetGrantedPermissions retrieves all granted permissions for a token
func (r *GrantedPermissionRepository) GetGrantedPermissions(ctx context.Context, tokenType domain.TokenType, tokenID uuid.UUID) ([]*domain.GrantedPermission, error) {
	// TODO: Implement actual granted permissions retrieval
	return []*domain.GrantedPermission{}, nil
}

// GetGrantedPermissionScopes retrieves only the scopes for a token (more efficient)
func (r *GrantedPermissionRepository) GetGrantedPermissionScopes(ctx context.Context, tokenType domain.TokenType, tokenID uuid.UUID) ([]string, error) {
	// TODO: Implement actual scope retrieval
	return []string{}, nil
}

// RevokePermission revokes a specific permission from a token
func (r *GrantedPermissionRepository) RevokePermission(ctx context.Context, grantID uuid.UUID, revokedBy string) error {
	// TODO: Implement actual permission revocation
	return nil
}

// RevokeAllPermissions revokes all permissions from a token
func (r *GrantedPermissionRepository) RevokeAllPermissions(ctx context.Context, tokenType domain.TokenType, tokenID uuid.UUID, revokedBy string) error {
	// TODO: Implement actual permission revocation
	return nil
}

// HasPermission checks if a token has a specific permission
func (r *GrantedPermissionRepository) HasPermission(ctx context.Context, tokenType domain.TokenType, tokenID uuid.UUID, scope string) (bool, error) {
	query := `
		SELECT 1 
		FROM granted_permissions gp
		JOIN available_permissions ap ON gp.permission_id = ap.id
		WHERE gp.token_type = $1 
		  AND gp.token_id = $2 
		  AND gp.scope = $3 
		  AND gp.revoked = false
		LIMIT 1
	`

	db := r.db.GetDB().(*sql.DB)
	var exists int
	err := db.QueryRowContext(ctx, query, string(tokenType), tokenID, scope).Scan(&exists)

	if err != nil {
		if err == sql.ErrNoRows {
			return false, nil
		}
		return false, fmt.Errorf("failed to check permission: %w", err)
	}

	return true, nil
}

// HasAnyPermission checks if a token has any of the specified permissions
func (r *GrantedPermissionRepository) HasAnyPermission(ctx context.Context, tokenType domain.TokenType, tokenID uuid.UUID, scopes []string) (map[string]bool, error) {
	if len(scopes) == 0 {
		return make(map[string]bool), nil
	}

	query := `
		SELECT gp.scope
		FROM granted_permissions gp
		JOIN available_permissions ap ON gp.permission_id = ap.id
		WHERE gp.token_type = $1 
		  AND gp.token_id = $2 
		  AND gp.scope = ANY($3)
		  AND gp.revoked = false
	`

	db := r.db.GetDB().(*sql.DB)
	rows, err := db.QueryContext(ctx, query, string(tokenType), tokenID, pq.Array(scopes))
	if err != nil {
		return nil, fmt.Errorf("failed to check permissions: %w", err)
	}
	defer rows.Close()

	result := make(map[string]bool)
	// Initialize all scopes as false
	for _, scope := range scopes {
		result[scope] = false
	}

	// Mark found permissions as true
	for rows.Next() {
		var scope string
		if err := rows.Scan(&scope); err != nil {
			return nil, fmt.Errorf("failed to scan permission scope: %w", err)
		}
		result[scope] = true
	}

	if err = rows.Err(); err != nil {
		return nil, fmt.Errorf("error iterating permission results: %w", err)
	}

	return result, nil
}