package navigation

import (
	"strings"
)

// Core routing logic separated from UI dependencies

type RoutePattern struct {
	parts  []string
	params []string
}

func CompileRoutePattern(path string) RoutePattern {
	var params []string
	parts := strings.Split(strings.Trim(path, "/"), "/")
	if len(parts) == 1 && parts[0] == "" {
		parts = []string{} // Handle root path
	}
	
	// Find parameters like :id, :name, etc.
	for _, part := range parts {
		if strings.HasPrefix(part, ":") {
			paramName := part[1:] // Remove the ':'
			// Simple validation: param name should start with letter
			if len(paramName) > 0 && isLetterCore(paramName[0]) {
				params = append(params, paramName)
			}
		}
	}
	
	return RoutePattern{parts, params}
}

func MatchRoute(routePattern RoutePattern, path string) map[string]string {
	pathParts := strings.Split(strings.Trim(path, "/"), "/")
	if len(pathParts) == 1 && pathParts[0] == "" {
		pathParts = []string{} // Handle root path
	}
	
	if len(pathParts) != len(routePattern.parts) {
		return nil
	}
	
	params := make(map[string]string)
	paramIndex := 0
	
	for i, routePart := range routePattern.parts {
		if strings.HasPrefix(routePart, ":") {
			// This is a parameter
			if paramIndex < len(routePattern.params) {
				params[routePattern.params[paramIndex]] = pathParts[i]
				paramIndex++
			}
		} else {
			// Static part must match exactly
			if routePart != pathParts[i] {
				return nil
			}
		}
	}
	
	return params
}

// isLetterCore checks if a byte is a letter
func isLetterCore(b byte) bool {
	return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z')
}