package httpapi

import (
	"errors"
	"net/http"
	"strings"

	"data-terminal-cloud/internal/concurrency"
	"data-terminal-cloud/internal/contentmodel"
)

func ListContentModelsHandler(service *contentmodel.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenantID := strings.TrimSpace(r.Header.Get("X-Tenant-Id"))
		if !validUUID(tenantID) {
			writeValidation(w, r, "租户参数不正确", FieldError{Field: "X-Tenant-Id", Message: "必须是有效UUID"})
			return
		}
		items, err := service.List(r.Context(), principal, tenantID)
		if err != nil {
			writeContentModelError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, map[string]any{"items": items})
	})
}

func CreateContentModelHandler(service *contentmodel.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		var input contentmodel.CreateInput
		if !decodeWebJSON(w, r, &input, "大模型配置参数不正确") {
			return
		}
		input.TenantID = strings.TrimSpace(r.Header.Get("X-Tenant-Id"))
		item, err := service.Create(r.Context(), principal, input, RequestID(r.Context()))
		if err != nil {
			writeContentModelError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		w.Header().Set("ETag", concurrency.FormatETag(item.Version))
		WriteJSON(w, r, http.StatusCreated, item)
	})
}

func TestContentModelHandler(service *contentmodel.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := resourcePrincipal(w, r, "id")
		if !ok {
			return
		}
		item, err := service.Test(r.Context(), principal, strings.TrimSpace(r.Header.Get("X-Tenant-Id")), r.PathValue("id"), RequestID(r.Context()))
		if err != nil {
			writeContentModelError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		w.Header().Set("ETag", concurrency.FormatETag(item.Version))
		WriteJSON(w, r, http.StatusOK, item)
	})
}

func ActivateContentModelHandler(service *contentmodel.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := resourcePrincipal(w, r, "id")
		if !ok {
			return
		}
		version, err := concurrency.ParseIfMatch(r)
		if err != nil {
			writeETagError(w, r, err)
			return
		}
		item, err := service.Activate(r.Context(), principal, strings.TrimSpace(r.Header.Get("X-Tenant-Id")), r.PathValue("id"), RequestID(r.Context()), version)
		if err != nil {
			writeContentModelError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		w.Header().Set("ETag", concurrency.FormatETag(item.Version))
		WriteJSON(w, r, http.StatusOK, item)
	})
}

func RevokeContentModelHandler(service *contentmodel.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := resourcePrincipal(w, r, "id")
		if !ok {
			return
		}
		version, err := concurrency.ParseIfMatch(r)
		if err != nil {
			writeETagError(w, r, err)
			return
		}
		item, err := service.Revoke(r.Context(), principal, strings.TrimSpace(r.Header.Get("X-Tenant-Id")), r.PathValue("id"), RequestID(r.Context()), version)
		if err != nil {
			writeContentModelError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		w.Header().Set("ETag", concurrency.FormatETag(item.Version))
		WriteJSON(w, r, http.StatusOK, item)
	})
}

func writeContentModelError(w http.ResponseWriter, r *http.Request, err error) {
	switch {
	case errors.Is(err, contentmodel.ErrInvalid):
		writeValidation(w, r, "大模型配置参数不正确", FieldError{Field: "model", Message: "请检查供应商、地址、模型ID、密钥和生成参数"})
	case errors.Is(err, contentmodel.ErrAccessDenied):
		WriteError(w, r, http.StatusForbidden, "CONTENT_MODEL_ACCESS_DENIED", "只有家庭负责人或管理员可以管理总结模型")
	case errors.Is(err, contentmodel.ErrNotFound):
		WriteError(w, r, http.StatusNotFound, "RESOURCE_NOT_FOUND", "大模型配置不存在")
	case errors.Is(err, contentmodel.ErrVersion):
		WriteError(w, r, http.StatusPreconditionFailed, "VERSION_CONFLICT", "配置已更新，请刷新后重试")
	case errors.Is(err, contentmodel.ErrTestRequired):
		WriteError(w, r, http.StatusConflict, "MODEL_TEST_REQUIRED", "请先通过连通性测试再激活")
	case errors.Is(err, contentmodel.ErrActiveRevoke):
		WriteError(w, r, http.StatusConflict, "ACTIVE_MODEL_CANNOT_REMOVE", "请先激活另一个模型，再移除当前模型")
	default:
		WriteError(w, r, http.StatusInternalServerError, "INTERNAL_ERROR", "大模型配置处理失败")
	}
}