package adminapi

import (
	"context"
	"net/http"
	"strconv"
)

// LogsView is one of a node's logs, as the node sent it.
type LogsView struct {
	Node   string   `json:"node"`
	Source string   `json:"source"`
	Lines  []string `json:"lines"`
	// Sources are every log the node can show: "agent", and one per engine
	// running there.
	Sources []string `json:"sources"`
	Error   string   `json:"error,omitempty"`
}

// maxLogLines bounds a request. The agent keeps two thousand lines of its own
// and a few hundred per engine, so more would only be refused further down.
const maxLogLines = 2000

// NodeLogs asks a node for the recent lines of one of its logs.
//
// Exported because the cluster page renders it server-side, the same as
// Nodes.
func (a *API) NodeLogs(ctx context.Context, node, source string, lines int) LogsView {
	if source == "" {
		source = "agent"
	}
	v := LogsView{Node: node, Source: source}
	lr := a.ctl.LogReader()
	if lr == nil {
		v.Error = "this control plane cannot read node logs"
		return v
	}
	if lines <= 0 {
		lines = 300
	}
	out, sources, err := lr.Logs(ctx, node, source, min(lines, maxLogLines))
	v.Lines, v.Sources = out, sources
	if err != nil {
		v.Error = err.Error()
	}
	if len(v.Sources) == 0 {
		v.Sources = []string{"agent"}
	}
	return v
}

func (a *API) nodeLogs(w http.ResponseWriter, r *http.Request) {
	lines, _ := strconv.Atoi(r.URL.Query().Get("lines"))
	v := a.NodeLogs(r.Context(), r.PathValue("id"), r.URL.Query().Get("source"), lines)
	code := http.StatusOK
	if v.Error != "" && len(v.Lines) == 0 {
		code = http.StatusBadGateway
	}
	writeJSON(w, code, v)
}