package services

import (
	"fmt"
	"strings"
)

// PromtailConfig 主机 Promtail 配置（推送至 lokiEndpoint，采集 logPath）
func PromtailConfig(lokiEndpoint, logPath string) string {
	return fmt.Sprintf(`server:
  http_listen_port: 9080
  grpc_listen_port: 0
  log_level: info

positions:
  filename: /tmp/positions.yaml

clients:
  - url: %s/loki/api/v1/push

scrape_configs:
  - job_name: app
    static_configs:
      - targets: [localhost]
        labels:
          job: app
          host: ${HOSTNAME}
          __path__: %s
`, lokiEndpoint, logPath)
}

// PromtailHelmValues DaemonSet 模式 Promtail Helm values
func PromtailHelmValues(lokiEndpoint string) string {
	return fmt.Sprintf(`config:
  clients:
    - url: %s/loki/api/v1/push

daemonset:
  enabled: true

serviceAccount:
  create: true

resources:
  limits:
    cpu: 200m
    memory: 128Mi
  requests:
    cpu: 100m
    memory: 64Mi

extraVolumes:
  - name: varlog
    hostPath:
      path: /var/log
  - name: varlibdockercontainers
    hostPath:
      path: /var/lib/docker/containers

extraVolumeMounts:
  - name: varlog
    mountPath: /var/log
    readOnly: true
  - name: varlibdockercontainers
    mountPath: /var/lib/docker/containers
    readOnly: true
`, lokiEndpoint)
}

// FluentbitConfig Sidecar 模式 Fluent Bit 配置（采集 logPath，推送至 lokiHost:lokiPort）
func FluentbitConfig(lokiHost, lokiPort, logPath, app, namespace string) string {
	return fmt.Sprintf(`[SERVICE]
    Flush          5
    Log_Level      info
    HTTP_Server    On
    HTTP_Listen    0.0.0.0
    HTTP_Port      2020

[INPUT]
    Name              tail
    Path              %s
    Tag               app.%s
    Refresh_Interval  5
    Mem_Buf_Limit     5MB
    Skip_Long_Lines   On
    Read_from_Head    True
    DB                /tmp/flb.db

[FILTER]
    Name    modify
    Match   app.*
    Add     namespace %s
    Add     app %s

[OUTPUT]
    Name                loki
    Match               *
    Host                %s
    Port                %s
    Labels              job=fluent-bit, app=%s, namespace=%s
`, logPath, app, namespace, app, lokiHost, lokiPort, app, namespace)
}

// FluentbitConfigMapYAML 包装 fluent-bit.conf 为 ConfigMap YAML（部署到 namespace）
func FluentbitConfigMapYAML(conf, namespace string) string {
	return fmt.Sprintf(`apiVersion: v1
kind: ConfigMap
metadata:
  name: fluent-bit-config
  namespace: %s
data:
  fluent-bit.conf: |
%s
`, namespace, indentBlock(conf, "    "))
}

// SidecarPatchYAML strategic merge patch：为 Deployment 注入 Fluent Bit sidecar 容器
const SidecarPatchYAML = `spec:
  template:
    spec:
      volumes:
      - name: app-logs
        emptyDir: {}
      - name: fluent-bit-config
        configMap:
          name: fluent-bit-config
      containers:
      - name: fluent-bit
        image: cr.fluentbit.io/fluent/fluent-bit:3.1.1
        imagePullPolicy: IfNotPresent
        volumeMounts:
        - name: app-logs
          mountPath: /var/log/app
          readOnly: true
        - name: fluent-bit-config
          mountPath: /fluent-bit/etc/
        resources:
          limits:
            cpu: 200m
            memory: 256Mi
          requests:
            cpu: 100m
            memory: 128Mi
`

// SidecarRemovePatchYAML strategic merge patch：从 Deployment 移除 Fluent Bit sidecar（卸载）
const SidecarRemovePatchYAML = `spec:
  template:
    spec:
      containers:
      - name: fluent-bit
        $patch: delete
      volumes:
      - name: app-logs
        $patch: delete
      - name: fluent-bit-config
        $patch: delete
`

// indentBlock 给每行加前缀（ConfigMap 嵌入配置需缩进）
func indentBlock(s, pad string) string {
	lines := strings.Split(s, "\n")
	for i, l := range lines {
		if l != "" {
			lines[i] = pad + l
		}
	}
	return strings.Join(lines, "\n")
}

// parseLokiURL 从 http://host:port 提取 host 与 port（Fluent Bit OUTPUT 需要）
func parseLokiURL(endpoint string) (host, port string) {
	u := strings.TrimSpace(endpoint)
	u = strings.TrimPrefix(u, "http://")
	u = strings.TrimPrefix(u, "https://")
	if i := strings.Index(u, "/"); i >= 0 {
		u = u[:i]
	}
	if i := strings.LastIndex(u, ":"); i >= 0 {
		return u[:i], u[i+1:]
	}
	return u, "3100"
}