package dnf90

import (
	"errors"
	"io"
	"net/http"

	dnfcompanion "longheng.io/server/internal/modules/dnf/companion"
	dnfrepo "longheng.io/server/internal/modules/dnf/repository"
	appkit "longheng.io/server/internal/platform/app"
	httpx "longheng.io/server/internal/platform/httpx"
	"longheng.io/server/internal/services/dnfbridge"
)

const companionAdminPath = "/local/companion"

func registerCompanionAdmin(env *appkit.Env, bridge *dnfbridge.Service) {
	if env == nil || env.AdminMux == nil || bridge == nil {
		return
	}

	readHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// 同时接受 character_id（内部/Server-90）与 characterId（GM 工具页面）。
		value, ok := dnfbridge.DecodeCompanionToolCharacterID(r.URL.RawQuery)
		if !ok {
			httpx.WriteJSON(w, http.StatusBadRequest, map[string]string{
				"error": "character_id (or characterId) must be a non-zero uint16",
			})
			return
		}
		state, err := bridge.CompanionControlState(r.Context(), value)
		if err != nil {
			httpx.WriteJSON(w, companionAdminErrorStatus(err), map[string]any{
				"error":        err.Error(),
				"character_id": value,
			})
			return
		}
		httpx.WriteJSON(w, http.StatusOK, map[string]any{
			"available": true,
			"mode":      "next_dungeon_frozen_snapshot",
			"state":     state,
		})
	})
	if env.AdminAuth != nil {
		readHandler = env.AdminAuth("platform", readHandler)
	}

	writeHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// 同时接受内部/Server-90 的 snake_case 与 GM 工具页面的 camelCase 协议
		// （含字符串形式的角色 ID）。解析细节见 dnfbridge/companion_tool_protocol.go。
		body, err := io.ReadAll(io.LimitReader(r.Body, 1<<20))
		if err != nil {
			httpx.WriteJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
			return
		}
		request, err := dnfbridge.DecodeCompanionToolRequest(body)
		if err != nil {
			httpx.WriteJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
			return
		}
		sources := append([]uint16(nil), request.SourceCharacterIDs...)
		if len(sources) == 0 && request.SourceCharacterID != 0 {
			sources = append(sources, request.SourceCharacterID)
		}
		if request.CharacterID == 0 || (request.Enabled && len(sources) == 0) {
			httpx.WriteJSON(w, http.StatusBadRequest, map[string]string{
				"error": "character_id and at least one enabled source_character_id must be non-zero uint16",
			})
			return
		}
		for _, source := range sources {
			if source == 0 {
				httpx.WriteJSON(w, http.StatusBadRequest, map[string]string{
					"error": "source_character_ids must contain only non-zero uint16 values",
				})
				return
			}
		}
		state, err := bridge.CompanionControlUpdateManyWithAIProfiles(
			r.Context(), request.CharacterID, request.ExpectedRevision,
			request.Enabled, sources, request.AI, request.AIProfiles,
			request.BalanceEnabled, request.ProgressionEnabled, request.RandomEquipmentEnabled,
		)
		if err != nil {
			httpx.WriteJSON(w, companionAdminErrorStatus(err), map[string]any{
				"error":             err.Error(),
				"character_id":      request.CharacterID,
				"expected_revision": request.ExpectedRevision,
			})
			return
		}
		httpx.WriteJSON(w, http.StatusOK, map[string]any{
			"available": true,
			"mode":      "next_dungeon_frozen_snapshot",
			"state":     state,
		})
	})
	if env.AdminDangerous != nil {
		writeHandler = env.AdminDangerous(
			"platform",
			httpx.AdminOperationID(http.MethodPost, companionAdminPath),
			writeHandler,
		)
	} else if env.AdminAuth != nil {
		writeHandler = env.AdminAuth("platform", writeHandler)
	}

	env.AdminMux.HandleFunc(companionAdminPath, func(w http.ResponseWriter, r *http.Request) {
		switch r.Method {
		case http.MethodGet:
			readHandler(w, r)
		case http.MethodPost:
			writeHandler(w, r)
		default:
			w.Header().Set("Allow", http.MethodGet+", "+http.MethodPost)
			httpx.WriteJSON(w, http.StatusMethodNotAllowed, map[string]string{"error": "method not allowed"})
		}
	})
}

func companionAdminErrorStatus(err error) int {
	switch {
	case errors.Is(err, dnfcompanion.ErrSelection),
		errors.Is(err, dnfcompanion.ErrSelf):
		return http.StatusBadRequest
	case errors.Is(err, dnfcompanion.ErrRevision),
		errors.Is(err, dnfcompanion.ErrAccount),
		errors.Is(err, dnfcompanion.ErrOnline),
		errors.Is(err, dnfcompanion.ErrSource),
		errors.Is(err, dnfcompanion.ErrSnapshot),
		errors.Is(err, dnfrepo.ErrCompanionAccountMismatch),
		errors.Is(err, dnfrepo.ErrCompanionCharacterUnavailable):
		return http.StatusConflict
	case errors.Is(err, dnfrepo.ErrCompanionReadUnavailable):
		return http.StatusServiceUnavailable
	default:
		return http.StatusInternalServerError
	}
}