package httpapi

import (
	"errors"
	"log/slog"
	"net/http"

	"data-terminal-cloud/internal/alerts"
	"data-terminal-cloud/internal/concurrency"
	"data-terminal-cloud/internal/idempotency"
)

func ListOpsAlertRoutingPoliciesHandler(service *alerts.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenant, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		items, e := service.ListRoutingPolicies(r.Context(), p, tenant)
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, map[string]any{"items": items})
	})
}
func CreateOpsAlertRoutingPolicyHandler(service *alerts.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenant, key, ok := opsCreateHeaders(w, r)
		if !ok {
			return
		}
		var body alerts.RoutingInput
		if !decodeWebJSON(w, r, &body, "告警路由参数不正确") {
			return
		}
		item, created, e := service.CreateRoutingPolicy(r.Context(), p, tenant, key, RequestID(r.Context()), body)
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		status := http.StatusCreated
		if !created {
			status = http.StatusOK
			w.Header().Set("Idempotency-Replayed", "true")
		}
		w.Header().Set("ETag", concurrency.FormatETag(item.RowVersion))
		WriteJSON(w, r, status, item)
	})
}
func ListOpsAlertDeliveryTestsHandler(service *alerts.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenant, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		items, e := service.ListDeliveryTests(r.Context(), p, tenant)
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, map[string]any{"items": items})
	})
}
func CreateOpsAlertDeliveryTestHandler(service *alerts.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := resourcePrincipal(w, r, "id")
		if !ok {
			return
		}
		tenant, key, ok := opsCreateHeaders(w, r)
		if !ok {
			return
		}
		var body alerts.DeliveryTestInput
		if !decodeWebJSON(w, r, &body, "告警接收器联通测试参数不正确") {
			return
		}
		item, created, e := service.CreateDeliveryTest(r.Context(), p, tenant, r.PathValue("id"), key, RequestID(r.Context()), body)
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		status := http.StatusCreated
		if !created {
			status = http.StatusOK
			w.Header().Set("Idempotency-Replayed", "true")
		}
		WriteJSON(w, r, status, item)
	})
}
func ListOpsAlertsHandler(service *alerts.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenant, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		items, e := service.ListIncidents(r.Context(), p, tenant, r.URL.Query().Get("status"))
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, map[string]any{"items": items})
	})
}
func GetOpsAlertHandler(service *alerts.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := resourcePrincipal(w, r, "id")
		if !ok {
			return
		}
		tenant, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		item, e := service.GetIncident(r.Context(), p, tenant, r.PathValue("id"))
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		w.Header().Set("ETag", concurrency.FormatETag(item.RowVersion))
		WriteJSON(w, r, http.StatusOK, item)
	})
}
func TransitionOpsAlertHandler(service *alerts.Service, action string) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := resourcePrincipal(w, r, "id")
		if !ok {
			return
		}
		tenant, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		version, e := concurrency.ParseIfMatch(r)
		if e != nil {
			writeETagError(w, r, e)
			return
		}
		var body struct {
			Note string `json:"note"`
		}
		if !decodeWebJSON(w, r, &body, "告警处置参数不正确") {
			return
		}
		item, e := service.TransitionIncident(r.Context(), p, tenant, r.PathValue("id"), RequestID(r.Context()), action, body.Note, version)
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		w.Header().Set("ETag", concurrency.FormatETag(item.RowVersion))
		WriteJSON(w, r, http.StatusOK, item)
	})
}
func ListOpsAlertSilencesHandler(service *alerts.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenant, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		items, e := service.ListSilences(r.Context(), p, tenant)
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		WriteJSON(w, r, http.StatusOK, map[string]any{"items": items})
	})
}
func CreateOpsAlertSilenceHandler(service *alerts.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenant, key, ok := opsCreateHeaders(w, r)
		if !ok {
			return
		}
		var body alerts.SilenceInput
		if !decodeWebJSON(w, r, &body, "告警静默参数不正确") {
			return
		}
		item, created, e := service.CreateSilence(r.Context(), p, tenant, key, RequestID(r.Context()), body)
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		status := http.StatusCreated
		if !created {
			status = http.StatusOK
			w.Header().Set("Idempotency-Replayed", "true")
		}
		w.Header().Set("ETag", concurrency.FormatETag(item.RowVersion))
		WriteJSON(w, r, status, item)
	})
}
func RevokeOpsAlertSilenceHandler(service *alerts.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, ok := resourcePrincipal(w, r, "id")
		if !ok {
			return
		}
		tenant, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		version, e := concurrency.ParseIfMatch(r)
		if e != nil {
			writeETagError(w, r, e)
			return
		}
		var body struct {
			Reason string `json:"reason"`
		}
		if !decodeWebJSON(w, r, &body, "静默撤销参数不正确") {
			return
		}
		item, e := service.RevokeSilence(r.Context(), p, tenant, r.PathValue("id"), RequestID(r.Context()), body.Reason, version)
		if e != nil {
			writeAlertError(w, r, e)
			return
		}
		w.Header().Set("ETag", concurrency.FormatETag(item.RowVersion))
		WriteJSON(w, r, http.StatusOK, item)
	})
}

func writeAlertError(w http.ResponseWriter, r *http.Request, e error) {
	switch {
	case errors.Is(e, alerts.ErrInvalid):
		writeValidation(w, r, "告警参数不正确", FieldError{Field: "alert", Message: "字段、状态、时间范围或引用不符合约束"})
	case errors.Is(e, alerts.ErrAccessDenied):
		WriteError(w, r, http.StatusForbidden, "OPS_ACCESS_DENIED", "当前账号没有所需的内部运营权限")
	case errors.Is(e, alerts.ErrNotFound):
		WriteError(w, r, http.StatusNotFound, "ALERT_NOT_FOUND", "告警、路由或静默记录不存在")
	case errors.Is(e, alerts.ErrVersionConflict):
		WriteError(w, r, http.StatusPreconditionFailed, "VERSION_CONFLICT", "资源版本已变化，请重新读取后再操作")
	case errors.Is(e, alerts.ErrStateConflict):
		WriteError(w, r, http.StatusConflict, "ALERT_STATE_CONFLICT", "当前告警或静默状态不允许该操作")
	case errors.Is(e, idempotency.ErrKeyConflict):
		WriteError(w, r, http.StatusConflict, "IDEMPOTENCY_KEY_CONFLICT", "重复请求识别码已被不同请求使用")
	default:
		slog.ErrorContext(r.Context(), "alert operation failed", "request_id", RequestID(r.Context()), "error", e)
		WriteError(w, r, http.StatusInternalServerError, "INTERNAL_ERROR", "告警处理失败")
	}
}