package restore

import (
	"context"
	"fmt"
	"time"

	"recover-server/internal/backup"
	"recover-server/internal/providers"
)

// Stage represents a restore stage
type Stage int

const (
	StageSync Stage = iota + 1
	StageEtc
	StageSelectiveEtc
	StageSSHKeys
	StageServices
	StageHealth
)

func (s Stage) String() string {
	names := map[Stage]string{
		StageSync:         "Sync /root and /opt",
		StageEtc:          "Stage /etc backup",
		StageSelectiveEtc: "Selective /etc restore",
		StageSSHKeys:      "Merge SSH keys",
		StageServices:     "Start services",
		StageHealth:       "Health verification",
	}
	return names[s]
}

// StageResult contains the result of a stage execution
type StageResult struct {
	Stage     Stage
	Success   bool
	Message   string
	Duration  time.Duration
	Error     error
}

// Pipeline orchestrates the restore process
type Pipeline struct {
	VM           *providers.VM
	BackupSource backup.BackupSource
	HostName     string
	SSHKeyPath   string      // Path to ephemeral private key
	SSHUser      string      // Usually "root"
	DryRun       bool
	Verbose      bool

	results []StageResult
}

// NewPipeline creates a new restore pipeline
func NewPipeline(vm *providers.VM, source backup.BackupSource, host, sshKeyPath string) *Pipeline {
	return &Pipeline{
		VM:           vm,
		BackupSource: source,
		HostName:     host,
		SSHKeyPath:   sshKeyPath,
		SSHUser:      "root",
		results:      make([]StageResult, 0),
	}
}

// Run executes all stages
func (p *Pipeline) Run(ctx context.Context) error {
	stages := []struct {
		stage Stage
		fn    func(context.Context) error
	}{
		{StageSync, p.runSync},
		{StageEtc, p.runEtcStaging},
		{StageSelectiveEtc, p.runSelectiveEtc},
		{StageSSHKeys, p.runSSHKeyMerge},
		{StageServices, p.runServices},
		{StageHealth, p.runHealth},
	}

	for _, s := range stages {
		start := time.Now()

		if p.Verbose {
			fmt.Printf("\n=== Stage %d: %s ===\n", s.stage, s.stage)
		}

		if p.DryRun {
			p.results = append(p.results, StageResult{
				Stage:    s.stage,
				Success:  true,
				Message:  "[DRY RUN] Would execute: " + s.stage.String(),
				Duration: 0,
			})
			continue
		}

		err := s.fn(ctx)
		result := StageResult{
			Stage:    s.stage,
			Success:  err == nil,
			Duration: time.Since(start),
			Error:    err,
		}

		if err != nil {
			result.Message = err.Error()
			p.results = append(p.results, result)
			return fmt.Errorf("stage %d (%s) failed: %w", s.stage, s.stage, err)
		}

		result.Message = "Completed successfully"
		p.results = append(p.results, result)
	}

	return nil
}

// Results returns all stage results
func (p *Pipeline) Results() []StageResult {
	return p.results
}

// sshTarget returns the SSH target string
func (p *Pipeline) sshTarget() string {
	return fmt.Sprintf("%s@%s", p.SSHUser, p.VM.PublicIP)
}