package service

import (
	"log/slog"

	"io"

	"codespace/internal/shell"
	"codespace/internal/workspace"
)

// ShellService manages interactive shells for workspaces.
type ShellService struct {
	workspaces workspace.Manager
	shells     shell.Manager
	logger     *slog.Logger
}

// NewShellService creates a ShellService.
// If lg is nil, slog.Default() is used.
func NewShellService(workspaces workspace.Manager, shells shell.Manager, lg *slog.Logger) *ShellService {
	if lg == nil {
		lg = slog.Default()
	}
	return &ShellService{workspaces: workspaces, shells: shells, logger: lg}
}

// Start starts an interactive shell for the given workspace.
func (s *ShellService) Start(workspaceID string) (string, error) {
	ws, err := s.workspaces.Get(workspaceID)
	if err != nil {
		return "", err
	}
	shellID, err := s.shells.Start(workspaceID, ws.Root)
	if err != nil {
		s.logger.Error("shell start failed", "workspace_id", workspaceID, "error", err)
		return "", err
	}
	status := s.shells.Status(workspaceID, shellID)
	s.logger.Info("shell started", "workspace_id", workspaceID, "shell_id", shellID, "pid", status.PID)
	return shellID, nil
}

// Stop stops the interactive shell for the given workspace.
func (s *ShellService) Stop(workspaceID string, shellID string) error {
	if _, err := s.workspaces.Get(workspaceID); err != nil {
		return err
	}
	if err := s.shells.Stop(workspaceID, shellID); err != nil {
		s.logger.Error("shell stop failed", "workspace_id", workspaceID, "error", err)
		return err
	}
	s.logger.Info("shell stopped", "workspace_id", workspaceID, "shell_id", shellID)
	return nil
}

// Restart restarts the interactive shell for the given workspace.
func (s *ShellService) Restart(workspaceID string, shellID string) (string, error) {
	ws, err := s.workspaces.Get(workspaceID)
	if err != nil {
		return "", err
	}
	newShellID, err := s.shells.Restart(workspaceID, shellID, ws.Root)
	if err != nil {
		s.logger.Error("shell restart failed", "workspace_id", workspaceID, "error", err)
		return "", err
	}
	status := s.shells.Status(workspaceID, newShellID)
	s.logger.Info("shell restarted", "workspace_id", workspaceID, "old_shell_id", shellID, "new_shell_id", newShellID, "pid", status.PID)
	return newShellID, nil
}

// Resize resizes the PTY for the given workspace.
func (s *ShellService) Resize(workspaceID string, shellID string, cols, rows int) error {
	if _, err := s.workspaces.Get(workspaceID); err != nil {
		return err
	}
	if err := s.shells.Resize(workspaceID, shellID, cols, rows); err != nil {
		s.logger.Error("shell resize failed", "workspace_id", workspaceID, "error", err)
		return err
	}
	s.logger.Info("shell resized", "workspace_id", workspaceID, "shell_id", shellID, "cols", cols, "rows", rows)
	return nil
}

// Status returns the shell status for the given workspace.
func (s *ShellService) Status(workspaceID string, shellID string) (shell.Status, error) {
	if _, err := s.workspaces.Get(workspaceID); err != nil {
		return shell.Status{}, err
	}
	return s.shells.Status(workspaceID, shellID), nil
}

// Subscribe subscribes to output events for the workspace shell.
func (s *ShellService) Subscribe(workspaceID string, shellID string) (shell.Subscription, error) {
	if _, err := s.workspaces.Get(workspaceID); err != nil {
		return nil, err
	}
	return s.shells.Subscribe(workspaceID, shellID)
}

// Input returns the stdin writer for the workspace shell.
func (s *ShellService) Input(workspaceID string, shellID string) (io.WriteCloser, error) {
	if _, err := s.workspaces.Get(workspaceID); err != nil {
		return nil, err
	}
	return s.shells.Stdin(workspaceID, shellID)
}

// ExitStatus returns the exit status for the workspace shell.
func (s *ShellService) ExitStatus(workspaceID string, shellID string) (shell.ExitInfo, error) {
	if _, err := s.workspaces.Get(workspaceID); err != nil {
		return shell.ExitInfo{}, err
	}
	return s.shells.ExitStatus(workspaceID, shellID)
}

// List returns all shells for the workspace.
func (s *ShellService) List(workspaceID string) ([]shell.ShellInfo, error) {
	if _, err := s.workspaces.Get(workspaceID); err != nil {
		return nil, err
	}
	return s.shells.List(workspaceID), nil
}