package main

import (
	"fmt"
	"net/url"
	"strings"
)

type Filter struct {
	Path  string
	Value string
}

func ParseFilters(query url.Values) []Filter {
	raw := query["filter"]
	if len(raw) == 0 {
		return nil
	}
	filters := make([]Filter, 0, len(raw))
	for _, f := range raw {
		path, value, ok := strings.Cut(f, ":")
		if !ok {
			continue
		}
		filters = append(filters, Filter{Path: path, Value: value})
	}
	return filters
}

func MatchAll(filters []Filter, event *Event) bool {
	for _, f := range filters {
		if !matchOne(f, event) {
			return false
		}
	}
	return true
}

func matchOne(f Filter, event *Event) bool {
	val, ok := resolveField(f.Path, event)
	if !ok {
		return false
	}
	return val == f.Value
}

func resolveField(path string, event *Event) (string, bool) {
	parts := strings.Split(path, ".")

	switch parts[0] {
	case "id":
		return event.ID, len(parts) == 1
	case "path":
		return event.Path, len(parts) == 1
	case "timestamp":
		return event.Timestamp.Format("2006-01-02T15:04:05Z07:00"), len(parts) == 1
	case "headers":
		if len(parts) != 2 {
			return "", false
		}
		val, ok := event.Headers[parts[1]]
		return val, ok
	case "payload":
		return navigateJSON(event.Payload, parts[1:])
	default:
		return "", false
	}
}

func navigateJSON(val any, parts []string) (string, bool) {
	if len(parts) == 0 {
		return fmt.Sprintf("%v", val), true
	}

	m, ok := val.(map[string]any)
	if !ok {
		return "", false
	}
	next, ok := m[parts[0]]
	if !ok {
		return "", false
	}
	return navigateJSON(next, parts[1:])
}