package httpapi

import (
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"strings"

	"github.com/easyai/easyai-ai-gateway/apps/api/internal/store"
)

// listRuntimePolicySets godoc
// @Summary 列出运行策略集
// @Description 管理端返回可分配给平台、模型或用户组的运行策略集。
// @Tags runtime
// @Produce json
// @Security BearerAuth
// @Success 200 {object} RuntimePolicySetListResponse
// @Failure 401 {object} ErrorEnvelope
// @Failure 403 {object} ErrorEnvelope
// @Failure 500 {object} ErrorEnvelope
// @Router /api/admin/runtime/policy-sets [get]
func (s *Server) listRuntimePolicySets(w http.ResponseWriter, r *http.Request) {
	items, err := s.store.ListRuntimePolicySets(r.Context())
	if err != nil {
		s.logger.Error("list runtime policy sets failed", "error", err)
		writeError(w, http.StatusInternalServerError, "list runtime policy sets failed")
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"items": items})
}

// getRunnerPolicy godoc
// @Summary 获取 Runner 策略
// @Description 管理端获取当前生效的默认 Runner 调度策略。
// @Tags runtime
// @Produce json
// @Security BearerAuth
// @Success 200 {object} store.RunnerPolicy
// @Failure 401 {object} ErrorEnvelope
// @Failure 403 {object} ErrorEnvelope
// @Failure 500 {object} ErrorEnvelope
// @Router /api/admin/runtime/runner-policy [get]
func (s *Server) getRunnerPolicy(w http.ResponseWriter, r *http.Request) {
	item, err := s.store.GetActiveRunnerPolicy(r.Context())
	if err != nil {
		s.logger.Error("get runner policy failed", "error", err)
		writeError(w, http.StatusInternalServerError, "get runner policy failed")
		return
	}
	writeJSON(w, http.StatusOK, item)
}

// updateRunnerPolicy godoc
// @Summary 更新 Runner 策略
// @Description 管理端写入默认 Runner 调度策略。
// @Tags runtime
// @Accept json
// @Produce json
// @Security BearerAuth
// @Param input body store.RunnerPolicyInput true "Runner 策略请求"
// @Success 200 {object} store.RunnerPolicy
// @Failure 400 {object} ErrorEnvelope
// @Failure 401 {object} ErrorEnvelope
// @Failure 403 {object} ErrorEnvelope
// @Failure 500 {object} ErrorEnvelope
// @Router /api/admin/runtime/runner-policy [patch]
func (s *Server) updateRunnerPolicy(w http.ResponseWriter, r *http.Request) {
	var input store.RunnerPolicyInput
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeError(w, http.StatusBadRequest, "invalid json body")
		return
	}
	if err := validateRunnerPolicyInput(input); err != nil {
		writeError(w, http.StatusBadRequest, err.Error(), "invalid_parameter")
		return
	}
	item, err := s.store.UpsertDefaultRunnerPolicy(r.Context(), input)
	if err != nil {
		s.logger.Error("update runner policy failed", "error", err)
		writeError(w, http.StatusInternalServerError, "update runner policy failed")
		return
	}
	writeJSON(w, http.StatusOK, item)
}

func validateRunnerPolicyInput(input store.RunnerPolicyInput) error {
	rawRules, exists := input.FailoverPolicy["actionRules"]
	if !exists {
		return nil
	}
	rules, ok := rawRules.([]any)
	if !ok {
		return errors.New("failoverPolicy.actionRules must be an array")
	}
	validActions := map[string]bool{
		"stop": true, "next": true, "cooldown_and_next": true, "demote_and_next": true, "disable_and_next": true,
	}
	for index, rawRule := range rules {
		rule, ok := rawRule.(map[string]any)
		if !ok {
			return fmt.Errorf("failoverPolicy.actionRules[%d] must be an object", index)
		}
		action := strings.TrimSpace(stringValue(rule["action"]))
		if !validActions[action] {
			return fmt.Errorf("failoverPolicy.actionRules[%d].action is invalid", index)
		}
		if target, present := rule["target"]; present {
			targetValue := strings.TrimSpace(stringValue(target))
			if targetValue != "model" && targetValue != "platform" {
				return fmt.Errorf("failoverPolicy.actionRules[%d].target is invalid", index)
			}
		}
		if !runnerActionRuleHasMatch(rule) {
			return fmt.Errorf("failoverPolicy.actionRules[%d] must include at least one match condition", index)
		}
		if action == "cooldown_and_next" && positiveJSONInteger(rule["cooldownSeconds"]) <= 0 {
			return fmt.Errorf("failoverPolicy.actionRules[%d].cooldownSeconds must be a positive integer", index)
		}
		if action == "demote_and_next" && positiveJSONInteger(rule["demoteSteps"]) <= 0 {
			return fmt.Errorf("failoverPolicy.actionRules[%d].demoteSteps must be a positive integer", index)
		}
	}
	return nil
}

func runnerActionRuleHasMatch(rule map[string]any) bool {
	for _, key := range []string{"categories", "codes", "errorCodes", "statusCodes", "keywords"} {
		switch values := rule[key].(type) {
		case []any:
			for _, value := range values {
				if strings.TrimSpace(fmt.Sprint(value)) != "" {
					return true
				}
			}
		case []string:
			for _, value := range values {
				if strings.TrimSpace(value) != "" {
					return true
				}
			}
		}
	}
	return false
}

func positiveJSONInteger(value any) int {
	switch typed := value.(type) {
	case int:
		if typed > 0 {
			return typed
		}
	case int64:
		if typed > 0 {
			return int(typed)
		}
	case float64:
		if typed > 0 && typed == float64(int(typed)) {
			return int(typed)
		}
	case json.Number:
		parsed, err := typed.Int64()
		if err == nil && parsed > 0 {
			return int(parsed)
		}
	}
	return 0
}

type updatePlatformDynamicPriorityRequest struct {
	DynamicPriority *int `json:"dynamicPriority" example:"10"`
	Reset           bool `json:"reset" example:"false"`
}

// updatePlatformDynamicPriority godoc
// @Summary 更新平台动态优先级
// @Description 管理端调整平台运行时动态优先级；reset 为 true 时清空动态值。
// @Tags runtime
// @Accept json
// @Produce json
// @Security BearerAuth
// @Param platformID path string true "平台 ID"
// @Param input body updatePlatformDynamicPriorityRequest true "动态优先级请求"
// @Success 200 {object} store.Platform
// @Failure 400 {object} ErrorEnvelope
// @Failure 401 {object} ErrorEnvelope
// @Failure 403 {object} ErrorEnvelope
// @Failure 404 {object} ErrorEnvelope
// @Failure 500 {object} ErrorEnvelope
// @Router /api/admin/platforms/{platformID}/dynamic-priority [patch]
func (s *Server) updatePlatformDynamicPriority(w http.ResponseWriter, r *http.Request) {
	var input updatePlatformDynamicPriorityRequest
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeError(w, http.StatusBadRequest, "invalid json body")
		return
	}
	var dynamicPriority *int
	if input.Reset {
		dynamicPriority = nil
	} else {
		if input.DynamicPriority == nil {
			writeError(w, http.StatusBadRequest, "dynamicPriority is required unless reset is true")
			return
		}
		if *input.DynamicPriority < 0 {
			writeError(w, http.StatusBadRequest, "dynamicPriority must be greater than or equal to 0")
			return
		}
		dynamicPriority = input.DynamicPriority
	}
	item, err := s.store.UpdatePlatformDynamicPriority(r.Context(), r.PathValue("platformID"), dynamicPriority)
	if err != nil {
		if store.IsNotFound(err) {
			writeError(w, http.StatusNotFound, "platform not found")
			return
		}
		s.logger.Error("update platform dynamic priority failed", "error", err)
		writeError(w, http.StatusInternalServerError, "update platform dynamic priority failed")
		return
	}
	writeJSON(w, http.StatusOK, item)
}

// restorePlatformModelRuntimeStatus godoc
// @Summary 恢复平台模型运行状态
// @Description 管理端手动解除平台模型停用、模型冷却、平台冷却或平台禁用状态，使其重新参与路由。
// @Tags runtime
// @Produce json
// @Security BearerAuth
// @Param platformModelID path string true "平台模型 ID"
// @Success 200 {object} store.ModelRateLimitStatus
// @Failure 401 {object} ErrorEnvelope
// @Failure 403 {object} ErrorEnvelope
// @Failure 404 {object} ErrorEnvelope
// @Failure 500 {object} ErrorEnvelope
// @Router /api/admin/runtime/model-rate-limits/{platformModelID}/restore [post]
func (s *Server) restorePlatformModelRuntimeStatus(w http.ResponseWriter, r *http.Request) {
	item, err := s.store.RestorePlatformModelRuntimeStatus(r.Context(), r.PathValue("platformModelID"))
	if err != nil {
		if store.IsNotFound(err) {
			writeError(w, http.StatusNotFound, "platform model not found")
			return
		}
		s.logger.Error("restore platform model runtime status failed", "error", err)
		writeError(w, http.StatusInternalServerError, "restore platform model runtime status failed")
		return
	}
	writeJSON(w, http.StatusOK, item)
}

// createRuntimePolicySet godoc
// @Summary 创建运行策略集
// @Description 管理端创建运行策略集，policyKey 和 name 必填。
// @Tags runtime
// @Accept json
// @Produce json
// @Security BearerAuth
// @Param input body store.RuntimePolicySetInput true "运行策略集请求"
// @Success 201 {object} store.RuntimePolicySet
// @Failure 400 {object} ErrorEnvelope
// @Failure 401 {object} ErrorEnvelope
// @Failure 403 {object} ErrorEnvelope
// @Failure 409 {object} ErrorEnvelope
// @Failure 500 {object} ErrorEnvelope
// @Router /api/admin/runtime/policy-sets [post]
func (s *Server) createRuntimePolicySet(w http.ResponseWriter, r *http.Request) {
	var input store.RuntimePolicySetInput
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeError(w, http.StatusBadRequest, "invalid json body")
		return
	}
	if !validRuntimePolicyInput(input) {
		writeError(w, http.StatusBadRequest, "policyKey and name are required")
		return
	}
	item, err := s.store.CreateRuntimePolicySet(r.Context(), input)
	if err != nil {
		if store.IsUniqueViolation(err) {
			writeError(w, http.StatusConflict, "runtime policy key already exists")
			return
		}
		s.logger.Error("create runtime policy set failed", "error", err)
		writeError(w, http.StatusInternalServerError, "create runtime policy set failed")
		return
	}
	writeJSON(w, http.StatusCreated, item)
}

// updateRuntimePolicySet godoc
// @Summary 更新运行策略集
// @Description 管理端更新运行策略集及其限流、重试、超时等策略配置。
// @Tags runtime
// @Accept json
// @Produce json
// @Security BearerAuth
// @Param policySetID path string true "运行策略集 ID"
// @Param input body store.RuntimePolicySetInput true "运行策略集请求"
// @Success 200 {object} store.RuntimePolicySet
// @Failure 400 {object} ErrorEnvelope
// @Failure 401 {object} ErrorEnvelope
// @Failure 403 {object} ErrorEnvelope
// @Failure 404 {object} ErrorEnvelope
// @Failure 409 {object} ErrorEnvelope
// @Failure 500 {object} ErrorEnvelope
// @Router /api/admin/runtime/policy-sets/{policySetID} [patch]
func (s *Server) updateRuntimePolicySet(w http.ResponseWriter, r *http.Request) {
	var input store.RuntimePolicySetInput
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeError(w, http.StatusBadRequest, "invalid json body")
		return
	}
	if !validRuntimePolicyInput(input) {
		writeError(w, http.StatusBadRequest, "policyKey and name are required")
		return
	}
	item, err := s.store.UpdateRuntimePolicySet(r.Context(), r.PathValue("policySetID"), input)
	if err != nil {
		if store.IsNotFound(err) {
			writeError(w, http.StatusNotFound, "runtime policy set not found")
			return
		}
		if store.IsUniqueViolation(err) {
			writeError(w, http.StatusConflict, "runtime policy key already exists")
			return
		}
		s.logger.Error("update runtime policy set failed", "error", err)
		writeError(w, http.StatusInternalServerError, "update runtime policy set failed")
		return
	}
	writeJSON(w, http.StatusOK, item)
}

// deleteRuntimePolicySet godoc
// @Summary 删除运行策略集
// @Description 管理端删除非默认运行策略集；默认策略集受保护。
// @Tags runtime
// @Produce json
// @Security BearerAuth
// @Param policySetID path string true "运行策略集 ID"
// @Success 204 "No Content"
// @Failure 401 {object} ErrorEnvelope
// @Failure 403 {object} ErrorEnvelope
// @Failure 404 {object} ErrorEnvelope
// @Failure 500 {object} ErrorEnvelope
// @Router /api/admin/runtime/policy-sets/{policySetID} [delete]
func (s *Server) deleteRuntimePolicySet(w http.ResponseWriter, r *http.Request) {
	if err := s.store.DeleteRuntimePolicySet(r.Context(), r.PathValue("policySetID")); err != nil {
		if store.IsNotFound(err) {
			writeError(w, http.StatusNotFound, "runtime policy set not found")
			return
		}
		if errors.Is(err, store.ErrProtectedDefault) {
			writeError(w, http.StatusForbidden, "default runtime policy set cannot be deleted")
			return
		}
		s.logger.Error("delete runtime policy set failed", "error", err)
		writeError(w, http.StatusInternalServerError, "delete runtime policy set failed")
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func validRuntimePolicyInput(input store.RuntimePolicySetInput) bool {
	return strings.TrimSpace(input.PolicyKey) != "" && strings.TrimSpace(input.Name) != ""
}