refactor(api): restructured API for type safety, maintainability and docs generation

- These changes makes the API incombatible with previous versions
- Added new types for error handling, success responses, and health checks.
- Updated health check logic to utilize the new types for better clarity and structure.
- Refactored existing handlers to improve response consistency and error handling.
- Updated Makefile to include a new target for generating API types from Swagger.
- Updated "new agent" API to respond an encrypted cert pair

internal/api/v1/metrics/system_info.go

@@ -0,0 +1,71 @@
+package metrics
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	agentPkg "github.com/yusing/go-proxy/agent/pkg/agent"
+	apitypes "github.com/yusing/go-proxy/internal/api/types"
+	"github.com/yusing/go-proxy/internal/metrics/period"
+	"github.com/yusing/go-proxy/internal/metrics/systeminfo"
+	"github.com/yusing/go-proxy/internal/net/gphttp/httpheaders"
+	"github.com/yusing/go-proxy/internal/net/gphttp/reverseproxy"
+	nettypes "github.com/yusing/go-proxy/internal/net/types"
+)
+
+type SystemInfoAggregate period.ResponseType[systeminfo.Aggregated] // @name SystemInfoAggregate
+
+// @x-id				"system_info"
+// @BasePath		/api/v1
+// @Summary		Get system info
+// @Description	Get system info
+// @Tags			metrics,websocket
+// @Produce		json
+// @Param			agent_addr	query		string	false	"Agent address"
+// @Param			period		query		string	false	"Period"
+// @Success		200			{object}	systeminfo.SystemInfo "no period specified"
+// @Success		200			{object}	SystemInfoAggregate "period specified"
+// @Failure		400			{object}	apitypes.ErrorResponse
+// @Failure		403			{object}	apitypes.ErrorResponse
+// @Failure		404			{object}	apitypes.ErrorResponse
+// @Failure		500			{object}	apitypes.ErrorResponse
+// @Router	 /metrics/system_info [get]
+func SystemInfo(c *gin.Context) {
+	query := c.Request.URL.Query()
+	agentAddr := query.Get("agent_addr")
+	query.Del("agent_addr")
+	if agentAddr == "" {
+		systeminfo.Poller.ServeHTTP(c)
+		return
+	}
+
+	agent, ok := agentPkg.GetAgent(agentAddr)
+	if !ok {
+		c.JSON(http.StatusNotFound, apitypes.Error("agent_addr not found"))
+		return
+	}
+
+	isWS := httpheaders.IsWebsocket(c.Request.Header)
+	if !isWS {
+		respData, status, err := agent.Forward(c.Request, agentPkg.EndpointSystemInfo)
+		if err != nil {
+			c.Error(apitypes.InternalServerError(err, "failed to forward request to agent"))
+			return
+		}
+		if status != http.StatusOK {
+			c.JSON(status, apitypes.Error(string(respData)))
+			return
+		}
+		c.JSON(status, respData)
+	} else {
+		rp := reverseproxy.NewReverseProxy("agent", nettypes.NewURL(agentPkg.AgentURL), agent.Transport())
+		header := c.Request.Header.Clone()
+		r, err := http.NewRequestWithContext(c.Request.Context(), c.Request.Method, agentPkg.EndpointSystemInfo+"?"+query.Encode(), nil)
+		if err != nil {
+			c.Error(apitypes.InternalServerError(err, "failed to create request"))
+			return
+		}
+		r.Header = header
+		rp.ServeHTTP(c.Writer, r)
+	}
+}

internal/api/v1/metrics/upime.go

@@ -0,0 +1,34 @@
+package metrics
+
+import (
+	"github.com/gin-gonic/gin"
+	"github.com/yusing/go-proxy/internal/metrics/period"
+	"github.com/yusing/go-proxy/internal/metrics/uptime"
+)
+
+type UptimeRequest struct {
+	Limit    int           `query:"limit" example:"10"`
+	Offset   string        `query:"offset" example:"10"`
+	Interval period.Filter `query:"interval" example:"1m"`
+	Keyword  string        `query:"keyword" example:""`
+} // @name UptimeRequest
+
+type UptimeAggregate period.ResponseType[uptime.Aggregated] // @name UptimeAggregate
+
+// @x-id				"uptime"
+// @BasePath		/api/v1
+// @Summary		Get uptime
+// @Description	Get uptime
+// @Tags			metrics,websocket
+// @Produce   json
+// @Param			request	query		UptimeRequest	false	"Request"
+// @Success		200		{object}	uptime.StatusByAlias "no period specified"
+// @Success		200		{object}	UptimeAggregate "period specified"
+// @Success   204   {object}	apitypes.ErrorResponse
+// @Failure		400		{object}	apitypes.ErrorResponse
+// @Failure		403		{object}	apitypes.ErrorResponse
+// @Failure		500		{object}	apitypes.ErrorResponse
+// @Router			/metrics/uptime [get]
+func Uptime(c *gin.Context) {
+	uptime.Poller.ServeHTTP(c)
+}