package main

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"strings"
	"time"

	"git.cin.su/m/Assistant/contracts/capability"
	fleetdomain "git.cin.su/m/Assistant/modules/capability/domain"
)

type fleetEndpoint struct {
	ProviderID string
	ModelID    string
	Tier       capability.FleetTier
	URL        string
	Headers    map[string]string
	Client     *http.Client
}

type fleetStatusResponse struct {
	Readiness capability.FleetReadiness `json:"readiness"`
	Preferred capability.FleetTier      `json:"preferred_tier"`
	Selected  capability.FleetTier      `json:"selected_tier,omitempty"`
	Error     string                    `json:"error,omitempty"`
}

func fleetReadinessHandler(client *http.Client, preferred capability.FleetTier, endpoints []fleetEndpoint) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		members := make([]capability.FleetMember, 0, len(endpoints))
		for _, endpoint := range endpoints {
			member := capability.FleetMember{ProviderInstanceID: capability.ProviderInstanceID(endpoint.ProviderID), ModelDescriptorID: capability.ModelDescriptorID(endpoint.ModelID), Tier: endpoint.Tier, Reason: "NOT_CONFIGURED"}
			if strings.TrimSpace(endpoint.URL) == "" {
				members = append(members, member)
				continue
			}
			request, err := http.NewRequestWithContext(r.Context(), http.MethodGet, endpoint.URL, nil)
			if err == nil {
				for name, value := range endpoint.Headers {
					request.Header.Set(name, value)
				}
				probeClient := endpoint.Client
				if probeClient == nil {
					probeClient = client
				}
				response, requestErr := probeClient.Do(request)
				if requestErr == nil {
					response.Body.Close()
					if response.StatusCode >= 200 && response.StatusCode < 300 {
						member.Ready, member.Reason = true, "AVAILABLE"
					} else {
						member.Reason = fmt.Sprintf("status=%s", response.Status)
					}
				} else {
					member.Reason = requestErr.Error()
				}
			}
			members = append(members, member)
		}
		readiness, err := fleetdomain.BuildFleetReadiness(time.Now().UnixMilli(), members)
		response := fleetStatusResponse{Readiness: readiness, Preferred: preferred}
		if err == nil {
			response.Selected, err = fleetdomain.SelectFleetTier(readiness, preferred)
		}
		if err != nil {
			response.Error = err.Error()
		}
		w.Header().Set("Content-Type", "application/json")
		if response.Selected == "" {
			w.WriteHeader(http.StatusServiceUnavailable)
		}
		_ = json.NewEncoder(w).Encode(response)
	})
}

func fleetContext(ctx context.Context) context.Context { return ctx }