package collect

import (
	"errors"
	"fmt"
	"time"

	"git.opencomputing.cn/yumoqing/host-metrics-collector/internal/model"
)

// Collector 将 System 的原始读数转换为 HMS 指标样本。
type Collector struct {
	sys     System
	hostID  string
	service string
}

// NewCollector 创建指标采集器；sys 为空时使用 gopsutil 实现。
func NewCollector(sys System, hostID, service string) *Collector {
	if sys == nil {
		sys = GopsutilSystem{}
	}
	return &Collector{sys: sys, hostID: hostID, service: service}
}

func (c *Collector) baseLabels(group string) map[string]string {
	return map[string]string{
		model.LabelHostID:      c.hostID,
		model.LabelService:     c.service,
		model.LabelMetricGroup: group,
	}
}

func withLabels(base, extra map[string]string) map[string]string {
	out := make(map[string]string, len(base)+len(extra))
	for k, v := range base {
		out[k] = v
	}
	for k, v := range extra {
		out[k] = v
	}
	return out
}

// CollectCore 采集核心指标（15s）：cpu.usage、mem.used_percent、load.1m。
func (c *Collector) CollectCore() ([]model.Sample, error) {
	var out []model.Sample
	var errs []error
	at := time.Now()
	base := c.baseLabels(model.GroupCore)

	if v, err := c.sys.CPUUsage(); err == nil {
		out = append(out, model.NewSample(model.MetricCPUUsage, v, at, base))
	} else {
		errs = append(errs, fmt.Errorf("cpu usage: %w", err))
	}

	if per, err := c.sys.PerCPUUsage(); err == nil {
		for i, v := range per {
			l := withLabels(base, map[string]string{"core": fmt.Sprintf("%d", i)})
			out = append(out, model.NewSample(model.MetricCPUUsage, v, at, l))
		}
	}

	if v, err := c.sys.MemUsedPercent(); err == nil {
		out = append(out, model.NewSample(model.MetricMemUsedPercent, v, at, base))
	} else {
		errs = append(errs, fmt.Errorf("mem usage: %w", err))
	}

	if v, err := c.sys.Load1(); err == nil {
		out = append(out, model.NewSample(model.MetricLoad1m, v, at, base))
	} else {
		errs = append(errs, fmt.Errorf("load1: %w", err))
	}

	return out, errors.Join(errs...)
}

// CollectDisk 采集磁盘指标（30s）：disk.used_percent、disk.io.read_bytes/write_bytes。
func (c *Collector) CollectDisk() ([]model.Sample, error) {
	var out []model.Sample
	var errs []error
	at := time.Now()
	base := c.baseLabels(model.GroupDisk)

	if usages, err := c.sys.DiskUsages(); err == nil {
		for _, u := range usages {
			l := withLabels(base, map[string]string{"mountpoint": u.Mountpoint})
			out = append(out, model.NewSample(model.MetricDiskUsedPercent, u.UsedPercent, at, l))
		}
	} else {
		errs = append(errs, fmt.Errorf("disk usage: %w", err))
	}

	if ios, err := c.sys.DiskIOCounters(); err == nil {
		for dev, io := range ios {
			l := withLabels(base, map[string]string{"device": dev})
			out = append(out, model.NewSample(model.MetricDiskIOReadBytes, float64(io.ReadBytes), at, l))
			out = append(out, model.NewSample(model.MetricDiskIOWriteBytes, float64(io.WriteBytes), at, l))
		}
	} else {
		errs = append(errs, fmt.Errorf("disk io: %w", err))
	}

	return out, errors.Join(errs...)
}

// CollectNetwork 采集网络指标（30s）：net.bytes_sent/recv、net.pkt_drop。
func (c *Collector) CollectNetwork() ([]model.Sample, error) {
	at := time.Now()
	base := c.baseLabels(model.GroupNetwork)

	ios, err := c.sys.NetIOCounters()
	if err != nil {
		return nil, fmt.Errorf("net io: %w", err)
	}

	out := make([]model.Sample, 0, len(ios)*3)
	for iface, io := range ios {
		l := withLabels(base, map[string]string{"interface": iface})
		out = append(out, model.NewSample(model.MetricNetBytesSent, float64(io.BytesSent), at, l))
		out = append(out, model.NewSample(model.MetricNetBytesRecv, float64(io.BytesRecv), at, l))
		out = append(out, model.NewSample(model.MetricNetPktDrop, float64(io.DropOut+io.DropIn), at, l))
	}
	return out, nil
}

// CollectProcess 采集进程指标（60s）：process.count、process.cpu、process.mem。
func (c *Collector) CollectProcess() ([]model.Sample, error) {
	at := time.Now()
	base := c.baseLabels(model.GroupProcess)

	procs, err := c.sys.Processes()
	if err != nil {
		return nil, fmt.Errorf("process list: %w", err)
	}

	out := make([]model.Sample, 0, len(procs)*2+1)
	out = append(out, model.NewSample(model.MetricProcessCount, float64(len(procs)), at, base))
	for _, p := range procs {
		l := withLabels(base, map[string]string{
			"pid":  fmt.Sprintf("%d", p.PID),
			"name": p.Name,
		})
		out = append(out, model.NewSample(model.MetricProcessCPU, p.CPUPercent, at, l))
		out = append(out, model.NewSample(model.MetricProcessMem, float64(p.MemBytes), at, l))
	}
	return out, nil
}