package httpapi

import (
	"errors"
	"net/http"
	"time"

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

func CreateOpsPriceBookHandler(service *billing.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenantID, key, ok := opsCreateHeaders(w, r)
		if !ok {
			return
		}
		var body billing.CreatePriceBookInput
		if !decodeWebJSON(w, r, &body, "费用单价版本参数不正确") {
			return
		}
		body.TenantID = tenantID
		item, created, err := service.CreatePriceBook(r.Context(), principal, key, RequestID(r.Context()), body)
		if err != nil {
			writeBillingError(w, r, err)
			return
		}
		status := http.StatusCreated
		if !created {
			status = http.StatusOK
			w.Header().Set("Idempotency-Replayed", "true")
		}
		w.Header().Set("ETag", concurrency.FormatETag(item.RowVersion))
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, status, item)
	})
}

func ListOpsPriceBooksHandler(service *billing.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenantID, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		items, err := service.ListPriceBooks(r.Context(), principal, tenantID)
		if err != nil {
			writeBillingError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, map[string]any{"items": items})
	})
}

func PublishOpsPriceBookHandler(service *billing.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := resourcePrincipal(w, r, "id")
		if !ok {
			return
		}
		tenantID, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		expected, err := concurrency.ParseIfMatch(r)
		if err != nil {
			writeETagError(w, r, err)
			return
		}
		var body struct {
			Reason string `json:"reason"`
		}
		if !decodeWebJSON(w, r, &body, "费用版本发布参数不正确") {
			return
		}
		item, err := service.PublishPriceBook(r.Context(), principal, tenantID, r.PathValue("id"), RequestID(r.Context()), body.Reason, expected)
		if err != nil {
			writeBillingError(w, r, err)
			return
		}
		w.Header().Set("ETag", concurrency.FormatETag(item.RowVersion))
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, item)
	})
}

func CreateOpsQuotaPolicyHandler(service *billing.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenantID, key, ok := opsCreateHeaders(w, r)
		if !ok {
			return
		}
		var body billing.QuotaInput
		if !decodeWebJSON(w, r, &body, "用量额度策略参数不正确") {
			return
		}
		item, created, err := service.CreateQuotaPolicy(r.Context(), principal, tenantID, key, RequestID(r.Context()), body)
		if err != nil {
			writeBillingError(w, r, err)
			return
		}
		status := http.StatusCreated
		if !created {
			status = http.StatusOK
			w.Header().Set("Idempotency-Replayed", "true")
		}
		w.Header().Set("ETag", concurrency.FormatETag(item.RowVersion))
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, status, item)
	})
}

func ListOpsQuotaPoliciesHandler(service *billing.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenantID, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		items, err := service.ListQuotaPolicies(r.Context(), principal, tenantID)
		if err != nil {
			writeBillingError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, map[string]any{"items": items})
	})
}

func GetOpsCostSummaryHandler(service *billing.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenantID, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		from, fromErr := time.Parse(time.RFC3339, r.URL.Query().Get("from"))
		to, toErr := time.Parse(time.RFC3339, r.URL.Query().Get("to"))
		if fromErr != nil || toErr != nil {
			writeValidation(w, r, "费用汇总时间范围不正确", FieldError{Field: "from/to", Message: "必须是RFC3339时间且范围不超过366天"})
			return
		}
		item, err := service.CostSummary(r.Context(), principal, tenantID, from, to)
		if err != nil {
			writeBillingError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, item)
	})
}

func GetFamilyUsageOverviewHandler(service *billing.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		from, to, timezone, ok := usageOverviewQuery(w, r)
		if !ok {
			return
		}
		item, err := service.FamilyUsageOverview(
			r.Context(), principal, r.PathValue("id"), r.URL.Query().Get("device_id"), timezone, from, to,
		)
		if err != nil {
			writeBillingError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, item)
	})
}

func GetOpsUsageOverviewHandler(service *billing.Service) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, ok := webPrincipal(w, r)
		if !ok {
			return
		}
		tenantID, ok := opsTenantHeader(w, r)
		if !ok {
			return
		}
		from, to, timezone, ok := usageOverviewQuery(w, r)
		if !ok {
			return
		}
		item, err := service.OpsUsageOverview(
			r.Context(), principal, tenantID, r.URL.Query().Get("household_id"), r.URL.Query().Get("device_id"), timezone, from, to,
		)
		if err != nil {
			writeBillingError(w, r, err)
			return
		}
		w.Header().Set("Cache-Control", "no-store")
		WriteJSON(w, r, http.StatusOK, item)
	})
}

func usageOverviewQuery(w http.ResponseWriter, r *http.Request) (time.Time, time.Time, string, bool) {
	from, fromErr := time.Parse(time.RFC3339, r.URL.Query().Get("from"))
	to, toErr := time.Parse(time.RFC3339, r.URL.Query().Get("to"))
	timezone := r.URL.Query().Get("timezone")
	if timezone == "" {
		timezone = "Asia/Shanghai"
	}
	if fromErr != nil || toErr != nil {
		writeValidation(w, r, "通话用量时间范围不正确", FieldError{Field: "from/to", Message: "必须是RFC3339时间且范围不超过366天"})
		return time.Time{}, time.Time{}, "", false
	}
	if _, err := time.LoadLocation(timezone); err != nil {
		writeValidation(w, r, "通话用量时区不正确", FieldError{Field: "timezone", Message: "必须是有效的IANA时区"})
		return time.Time{}, time.Time{}, "", false
	}
	return from, to, timezone, true
}

func writeBillingError(w http.ResponseWriter, r *http.Request, err error) {
	switch {
	case errors.Is(err, billing.ErrInvalid):
		writeValidation(w, r, "用量、费用或额度参数不正确", FieldError{Field: "billing", Message: "字段、单位、时区、金额或范围不符合约束"})
	case errors.Is(err, billing.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(err, billing.ErrNotFound):
		WriteError(w, r, http.StatusNotFound, "RESOURCE_NOT_FOUND", "费用或额度资源不存在")
	case errors.Is(err, billing.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(err, billing.ErrSelfApproval):
		WriteError(w, r, http.StatusConflict, "SELF_APPROVAL_FORBIDDEN", "费用版本创建人不能审批自己的变更")
	case errors.Is(err, billing.ErrStateConflict):
		WriteError(w, r, http.StatusConflict, "BILLING_STATE_CONFLICT", "当前状态不允许执行该操作")
	case errors.Is(err, 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")
	case errors.Is(err, idempotency.ErrInProgress):
		WriteError(w, r, http.StatusConflict, "IDEMPOTENCY_IN_PROGRESS", "相同请求正在处理中")
	default:
		WriteError(w, r, http.StatusInternalServerError, "INTERNAL_ERROR", "用量费用处理失败")
	}
}