package server

import (
	"net/http"
	"strings"

	"forgejo.riotpiao.com/rock/homelab-frontend/internal/serviceadapter"
)

// Router implements an HTTP handler that routes health endpoints,
// ServiceAdapter X-Service requests, Temporal workflow endpoints,
// S3/SigV4 endpoints, and other requests to upstream handlers.
type Router struct {
	healthChecker     *HealthChecker
	dispatcher        *serviceadapter.Dispatcher
	temporalHandler   http.Handler
	s3Handler         http.Handler // S3/SigV4 proxy
	upstreamHandler   http.Handler
}

// NewRouter creates a new router with health endpoints.
// Health endpoints (/healthz and /readyz) are handled locally.
// X-Service requests are dispatched via ServiceAdapter CRD.
// Temporal endpoints (/workflow*) are routed to temporalHandler.
// S3 endpoints (/v1/s3/*) are routed to s3Handler.
// All other paths are passed to the upstream handler.
func NewRouter(healthChecker *HealthChecker, dispatcher *serviceadapter.Dispatcher, temporalHandler http.Handler, s3Handler http.Handler, upstreamHandler http.Handler) *Router {
	return &Router{
		healthChecker:   healthChecker,
		dispatcher:      dispatcher,
		temporalHandler: temporalHandler,
		s3Handler:       s3Handler,
		upstreamHandler: upstreamHandler,
	}
}

// ServeHTTP implements http.Handler.
// Priority order:
// 1. /healthz and /readyz to health handlers
// 2. X-Service header to ServiceAdapter dispatcher (phase 8)
// 3. /workflow* to temporal handler
// 4. /v1/s3/* to S3/SigV4 handler
// 5. All other paths to upstream handler (phase 0-7)
func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	// Health endpoints first
	switch req.URL.Path {
	case "/healthz":
		LivenessHandler(r.healthChecker)(w, req)
		return
	case "/readyz":
		ReadinessHandler(r.healthChecker)(w, req)
		return
	}

	// X-Service (ServiceAdapter) routing - checked before path-based routing
	if req.Header.Get("X-Service") != "" {
		if r.dispatcher != nil {
			r.dispatcher.Dispatch(w, req)
			return
		}
	}

	// Workflow endpoints
	switch req.URL.Path {
	case "/workflow", "/workflow/health", "/workflow/metrics":
		r.temporalHandler.ServeHTTP(w, req)
		return
	}

	// S3/SigV4 proxy endpoints
	if req.URL.Path != "" && req.URL.Path[0] == '/' && len(req.URL.Path) > 1 {
		// Check for /v1/s3/* pattern
		parts := strings.Split(strings.TrimPrefix(req.URL.Path, "/"), "/")
		if len(parts) >= 3 && parts[0] == "v1" && parts[1] == "s3" {
			if r.s3Handler != nil {
				r.s3Handler.ServeHTTP(w, req)
				return
			}
		}
	}

	// Default: upstream handler (all other paths)
	r.upstreamHandler.ServeHTTP(w, req)
}