package embedded

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"

	"github.com/fujin/anthropic-proxy/internal/config"
	"github.com/rs/zerolog/log"
)

type Perses struct {
	cfg       config.EmbeddedConfig
	proxyPort int
	cmd       *exec.Cmd
	tmpDir    string
}

func NewPerses(cfg config.EmbeddedConfig, proxyPort int) *Perses {
	return &Perses{cfg: cfg, proxyPort: proxyPort}
}

func (p *Perses) Start() error {
	bin, err := ensureBinary("perses", p.cfg.PersesBinary, p.cfg.BinDir)
	if err != nil {
		return fmt.Errorf("perses: %w", err)
	}

	p.tmpDir, err = os.MkdirTemp("", "perses-*")
	if err != nil {
		return fmt.Errorf("create temp dir: %w", err)
	}

	if err := p.writeServerConfig(); err != nil {
		return fmt.Errorf("write server config: %w", err)
	}
	if err := p.writeDatasourceProvision(); err != nil {
		return fmt.Errorf("write datasource provision: %w", err)
	}
	if err := p.writeDashboardProvision(); err != nil {
		return fmt.Errorf("write dashboard provision: %w", err)
	}

	p.cmd = exec.Command(bin,
		"--config", filepath.Join(p.tmpDir, "config.yaml"),
		"-web.listen-address", fmt.Sprintf(":%d", p.cfg.Port),
	)
	p.cmd.Dir = filepath.Dir(bin)
	p.cmd.Stdout = &logWriter{level: "info", component: "perses"}
	p.cmd.Stderr = &logWriter{level: "error", component: "perses"}

	if err := p.cmd.Start(); err != nil {
		return fmt.Errorf("start perses: %w", err)
	}

	log.Info().
		Str("binary", bin).
		Int("port", p.cfg.Port).
		Str("config", p.tmpDir).
		Msg("perses started")

	return nil
}

func (p *Perses) Stop() {
	if p.cmd != nil && p.cmd.Process != nil {
		_ = p.cmd.Process.Kill()
		_ = p.cmd.Wait()
	}
	if p.tmpDir != "" {
		_ = os.RemoveAll(p.tmpDir)
	}
}

func (p *Perses) Running() bool {
	return p.cmd != nil && p.cmd.Process != nil && p.cmd.ProcessState == nil
}

func (p *Perses) writeServerConfig() error {
	provisionDir := filepath.Join(p.tmpDir, "provisions")
	if err := os.MkdirAll(filepath.Join(provisionDir, "datasources"), 0o755); err != nil {
		return err
	}
	if err := os.MkdirAll(filepath.Join(provisionDir, "dashboards"), 0o755); err != nil {
		return err
	}

	cfg := fmt.Sprintf(`provisioning:
  interval: 1m
  folders:
    - %s
database:
  file:
    folder: %s/data
    extension: json
security:
  readonly: false
  enable_auth: false
`, provisionDir, p.tmpDir)

	return os.WriteFile(filepath.Join(p.tmpDir, "config.yaml"), []byte(cfg), 0o644)
}

func (p *Perses) writeDatasourceProvision() error {
	ds := fmt.Sprintf(`kind: Datasource
metadata:
  name: victoria-metrics
  project: anthropic-proxy
spec:
  default: true
  plugin:
    kind: PrometheusDatasource
    spec:
      directUrl: http://localhost:%d
`, p.cfg.VMPort)

	return os.WriteFile(
		filepath.Join(p.tmpDir, "provisions", "datasources", "vm.yaml"),
		[]byte(ds), 0o644,
	)
}

func (p *Perses) writeDashboardProvision() error {
	dashData, err := DashboardJSON()
	if err != nil {
		return err
	}
	return os.WriteFile(
		filepath.Join(p.tmpDir, "provisions", "dashboards", "proxy.json"),
		dashData, 0o644,
	)
}