package api

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

// LauncherAPIHost is the official JP launcher API host observed from the PC launcher.
const LauncherAPIHost = "api-launcher-jp.yo-star.com"

func (s *Server) handleLauncherBootstrap(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		writeErrorJSON(w, http.StatusMethodNotAllowed, "method_not_allowed", "method not allowed")
		return
	}
	sum := s.releaseSummary()
	status := http.StatusOK
	if !sum.Ready || sum.Snapshot == nil {
		status = http.StatusServiceUnavailable
	}
	writeNoStoreJSON(w, status, s.launcherBootstrapBody(sum))
}

func (s *Server) handleLauncherGameConfig(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		writeErrorJSON(w, http.StatusMethodNotAllowed, "method_not_allowed", "method not allowed")
		return
	}
	sum := s.releaseSummary()
	if !sum.Ready || sum.Snapshot == nil {
		writeLauncherEnvelope(w, http.StatusServiceUnavailable, 503, "release not ready", LauncherGameConfigJSONData{
			ResourceBootstrapURL: s.launcherBootstrapURL(),
			Scope:                "resource_bootstrap_only",
		})
		return
	}
	snap := sum.Snapshot
	data := LauncherGameConfigData{
		GameLatestVersion:    defaultString(s.launcherLatestVersion(snap), snap.AppVersion),
		GameLatestFilePath:   s.launcherLatestFilePath(snap),
		GameStartExeName:     s.launcherStartExeName(snap),
		GameStartParams:      s.launcherStartParams(snap),
		ResourceBootstrapURL: s.launcherBootstrapURL(),
		ServerInfoURL:        s.serverInfoURL(),
		ClientPatchBaseURL:   s.clientPatchBaseURL(),
		Scope:                "resource_bootstrap_only",
	}
	if snap.LauncherMetadata != nil && snap.LauncherMetadata.GameLowestVersion != "" {
		data.GameLowestVersion = snap.LauncherMetadata.GameLowestVersion
	}
	writeLauncherEnvelope(w, http.StatusOK, 200, "ok", data)
}

func (s *Server) handleLauncherGameConfigJSON(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		writeErrorJSON(w, http.StatusMethodNotAllowed, "method_not_allowed", "method not allowed")
		return
	}
	sum := s.releaseSummary()
	if !sum.Ready || sum.Snapshot == nil {
		writeLauncherEnvelope(w, http.StatusServiceUnavailable, 503, "release not ready", LauncherGameConfigJSONData{
			URL:                  s.launcherBootstrapURL(),
			ResourceBootstrapURL: s.launcherBootstrapURL(),
			Scope:                "resource_bootstrap_only",
		})
		return
	}
	writeLauncherEnvelope(w, http.StatusOK, 200, "ok", LauncherGameConfigJSONData{
		URL:                   s.launcherBootstrapJSONURL(r.URL.Query()),
		ResourceBootstrapURL:  s.launcherBootstrapURL(),
		PackageUpdateManifest: false,
		Scope:                 "resource_bootstrap_only",
	})
}

func (s *Server) handleLauncherCdnConfig(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		writeErrorJSON(w, http.StatusMethodNotAllowed, "method_not_allowed", "method not allowed")
		return
	}
	writeLauncherEnvelope(w, http.StatusOK, 200, "ok", LauncherCdnConfigData{
		PrimaryCDN:            strings.TrimRight(s.cfg.PublicBaseURL, "/"),
		BackupCDN:             strings.TrimRight(s.cfg.PublicBaseURL, "/"),
		ResourceBootstrapURL:  s.launcherBootstrapURL(),
		PackageUpdateManifest: false,
		Scope:                 "resource_bootstrap_only",
	})
}

func (s *Server) launcherBootstrapBody(sum ReleaseSummary) LauncherBootstrapResponse {
	publicBase := strings.TrimRight(s.cfg.PublicBaseURL, "/")
	body := LauncherBootstrapResponse{
		Service: "bat-api",
		Ready:   sum.Ready,
		LauncherAPI: LauncherAPIInfo{
			Host: LauncherAPIHost,
			ObservedResourceRelevantEndpoints: []string{
				"/api/launcher/game/config",
				"/api/launcher/game/config/json",
				"/api/launcher/advanced/game/download/cdn",
			},
			CompatibilityScope: "resource_bootstrap_only",
		},
		Policy: LauncherPolicy{
			Source:                   "rust_bat_snapshot",
			DownloadsLauncherPackage: false,
			EmulatesLoginOrGateway:   false,
			PackageUpdateManifest:    false,
		},
		Resource: LauncherResource{
			Release:            sum.Snapshot,
			ServerInfoURL:      s.serverInfoURL(),
			ClientPatchBaseURL: s.clientPatchBaseURL(),
		},
		Endpoints: LauncherEndpointSet{
			Bootstrap:              publicBase + "/v1/bootstrap",
			LauncherBootstrap:      publicBase + "/v1/launcher/bootstrap",
			ServerInfo:             s.serverInfoURL(),
			ClientPatchBase:        s.clientPatchBaseURL(),
			LauncherGameConfig:     publicBase + "/" + LauncherAPIHost + "/api/launcher/game/config",
			LauncherGameConfigJSON: publicBase + "/" + LauncherAPIHost + "/api/launcher/game/config/json",
			LauncherCdnConfig:      publicBase + "/" + LauncherAPIHost + "/api/launcher/advanced/game/download/cdn",
		},
	}
	if sum.Snapshot != nil {
		body.GameMainConfig = sum.Snapshot.GameMainConfig
		body.LauncherMetadata = sum.Snapshot.LauncherMetadata
		if rewritten, ok := rewriteAddressablesRoot(sum.Snapshot.AddressablesRoot, publicBase); ok {
			body.AddressablesCatalogURLRoot = rewritten
		}
	}
	return body
}

func (s *Server) releaseSummary() ReleaseSummary {
	if idx := s.index(); idx != nil {
		return idx.Summary()
	}
	return ReleaseSummary{}
}

func (s *Server) serverInfoURL() string {
	return strings.TrimRight(s.cfg.PublicBaseURL, "/") + "/" + ServerInfoHost + "/server-info.json"
}

func (s *Server) clientPatchBaseURL() string {
	return strings.TrimRight(s.cfg.PublicBaseURL, "/") + "/" + ClientPatchHost
}

func (s *Server) launcherBootstrapURL() string {
	return strings.TrimRight(s.cfg.PublicBaseURL, "/") + "/v1/launcher/bootstrap"
}

func (s *Server) launcherBootstrapJSONURL(query url.Values) string {
	base := strings.TrimRight(s.cfg.PublicBaseURL, "/") + "/" + LauncherAPIHost + "/api/launcher/resource/bootstrap.json"
	values := url.Values{}
	for _, key := range []string{"version", "file_path"} {
		if value := query.Get(key); value != "" {
			values.Set(key, value)
		}
	}
	if encoded := values.Encode(); encoded != "" {
		return base + "?" + encoded
	}
	return base
}

func (s *Server) launcherLatestVersion(snap *SnapshotSummary) string {
	if snap.LauncherMetadata != nil && snap.LauncherMetadata.GameLatestVersion != "" {
		return snap.LauncherMetadata.GameLatestVersion
	}
	return snap.AppVersion
}

func (s *Server) launcherLatestFilePath(snap *SnapshotSummary) string {
	if snap.LauncherMetadata != nil {
		return snap.LauncherMetadata.GameLatestFilePath
	}
	return ""
}

func (s *Server) launcherStartExeName(snap *SnapshotSummary) string {
	if snap.LauncherMetadata != nil {
		return snap.LauncherMetadata.GameStartExeName
	}
	return ""
}

func (s *Server) launcherStartParams(snap *SnapshotSummary) []string {
	if snap.LauncherMetadata != nil && len(snap.LauncherMetadata.GameStartParams) > 0 {
		return append([]string(nil), snap.LauncherMetadata.GameStartParams...)
	}
	return []string{}
}

func writeLauncherEnvelope[T any](w http.ResponseWriter, status int, code int, message string, data T) {
	writeNoStoreJSON(w, status, LauncherEnvelope[T]{
		Code:    code,
		Message: message,
		Data:    data,
	})
}

func launcherHostPath(path string) string {
	return fmt.Sprintf("/%s%s", LauncherAPIHost, path)
}