// Package tui is the impure shell layer for the TUI.
// It converts pure Intent values into real I/O via tea.Cmd.
package tui

import (
	"fmt"
	"time"

	tea "github.com/charmbracelet/bubbletea"

	puretui "github.com/enmanuel/agents/pkg/tui"
	"github.com/enmanuel/agents/shell/process"
)

// Adapter bridges pure Intents with the process Manager.
type Adapter struct {
	mgr *process.Manager
}

// NewAdapter creates an Adapter with the given Manager.
func NewAdapter(mgr *process.Manager) *Adapter {
	return &Adapter{mgr: mgr}
}

// RunIntent converts a pure Intent into a bubbletea Cmd that performs I/O.
func (a *Adapter) RunIntent(intent puretui.Intent) tea.Cmd {
	switch intent.Kind {

	case puretui.IntentLoadAgents:
		return a.loadAgents()

	case puretui.IntentStartAgent:
		return a.startAgent(intent.AgentID)

	case puretui.IntentStopAgent:
		return a.stopAgent(intent.AgentID)

	case puretui.IntentKillAgent:
		return a.killAgent(intent.AgentID)

	case puretui.IntentRestartAgent:
		return a.restartAgent(intent.AgentID)

	case puretui.IntentLoadLogs:
		return a.loadLogs(intent.AgentID)

	case puretui.IntentTick:
		return a.tick()

	case puretui.IntentQuit:
		return tea.Quit

	default:
		return nil
	}
}

func (a *Adapter) loadAgents() tea.Cmd {
	return func() tea.Msg {
		statuses, err := a.mgr.StatusAll()
		if err != nil {
			return puretui.MsgAgentsLoaded{}
		}

		views := make([]puretui.AgentView, len(statuses))
		for i, s := range statuses {
			v := puretui.AgentView{
				ID:      s.ID,
				Name:    s.Name,
				Version: s.Version,
				Desc:    s.Desc,
				Enabled: s.Enabled,
				Running: s.Running,
				PID:     s.PID,
			}

			if s.Running {
				if stats, err := a.mgr.Stats(s.ID); err == nil {
					v.Uptime = formatUptime(stats.UptimeSecs)
					v.Memory = formatBytes(stats.MemRSSKB * 1024)
					v.CPU = fmt.Sprintf("%.1f%%", stats.CPUPct)
					v.LogSize = formatBytes(stats.LogBytes)
				}
			}

			views[i] = v
		}

		return puretui.MsgAgentsLoaded{Agents: views}
	}
}

func (a *Adapter) startAgent(id string) tea.Cmd {
	return func() tea.Msg {
		agents, err := a.mgr.Scan()
		if err != nil {
			return puretui.MsgActionDone{AgentID: id, Action: "Start", Err: err}
		}
		for _, agent := range agents {
			if agent.ID == id {
				err = a.mgr.Start(agent)
				// Give the process a moment to start.
				if err == nil {
					time.Sleep(500 * time.Millisecond)
				}
				return puretui.MsgActionDone{AgentID: id, Action: "Start", Err: err}
			}
		}
		return puretui.MsgActionDone{AgentID: id, Action: "Start", Err: fmt.Errorf("agent not found")}
	}
}

func (a *Adapter) stopAgent(id string) tea.Cmd {
	return func() tea.Msg {
		err := a.mgr.Stop(id)
		return puretui.MsgActionDone{AgentID: id, Action: "Stop", Err: err}
	}
}

func (a *Adapter) killAgent(id string) tea.Cmd {
	return func() tea.Msg {
		err := a.mgr.Kill(id)
		return puretui.MsgActionDone{AgentID: id, Action: "Kill", Err: err}
	}
}

func (a *Adapter) restartAgent(id string) tea.Cmd {
	return func() tea.Msg {
		// Stop first (ignore error if not running)
		_ = a.mgr.Stop(id)
		time.Sleep(300 * time.Millisecond)

		agents, err := a.mgr.Scan()
		if err != nil {
			return puretui.MsgActionDone{AgentID: id, Action: "Restart", Err: err}
		}
		for _, agent := range agents {
			if agent.ID == id {
				err = a.mgr.Start(agent)
				if err == nil {
					time.Sleep(500 * time.Millisecond)
				}
				return puretui.MsgActionDone{AgentID: id, Action: "Restart", Err: err}
			}
		}
		return puretui.MsgActionDone{AgentID: id, Action: "Restart", Err: fmt.Errorf("agent not found")}
	}
}

func (a *Adapter) loadLogs(id string) tea.Cmd {
	return func() tea.Msg {
		lines, err := a.mgr.LogTail(id, 100)
		if err != nil {
			return puretui.MsgLogsLoaded{Lines: []string{"Error: " + err.Error()}}
		}
		return puretui.MsgLogsLoaded{Lines: lines}
	}
}

func (a *Adapter) tick() tea.Cmd {
	return tea.Tick(3*time.Second, func(time.Time) tea.Msg {
		return puretui.MsgTick{}
	})
}

// ── formatting helpers ───────────────────────────────────────────────────

func formatUptime(secs int64) string {
	if secs < 0 {
		return "n/a"
	}
	d := secs / 86400
	h := (secs % 86400) / 3600
	m := (secs % 3600) / 60
	if d > 0 {
		return fmt.Sprintf("%dd %dh", d, h)
	}
	if h > 0 {
		return fmt.Sprintf("%dh %dm", h, m)
	}
	return fmt.Sprintf("%dm", m)
}

func formatBytes(bytes int64) string {
	switch {
	case bytes >= 1<<30:
		return fmt.Sprintf("%.1f GB", float64(bytes)/float64(1<<30))
	case bytes >= 1<<20:
		return fmt.Sprintf("%.1f MB", float64(bytes)/float64(1<<20))
	case bytes >= 1<<10:
		return fmt.Sprintf("%.1f KB", float64(bytes)/float64(1<<10))
	default:
		return fmt.Sprintf("%d B", bytes)
	}
}