package main

import (
	"fmt"
	"runtime"
	"spitfire-installer/spm"
)

// Installer manages the download, decompression, and installation processes.
type Installer struct {
	// Progress info from SPM
	Progress int
	Task     string

	// Internal states
	IsDownloading  bool
	IsInstalling   bool
	DoneDownload   bool
	DoneInstall    bool
	LastError      error
	PendingInstall bool
}

// NewInstaller creates a new Installer with initial state.
func NewInstaller() *Installer {
	return &Installer{}
}

// StartDownloadDecompress starts the download and decompression in a background goroutine.
func (inst *Installer) StartDownloadDecompress() {
	inst.IsDownloading = true
	go func() {
		defer func() {
			inst.IsDownloading = false
			// Signal that download phase is complete.
			inst.DoneDownload = (inst.LastError == nil)
			// If a final install was requested, go ahead.
			if inst.PendingInstall && inst.DoneDownload && !inst.IsInstalling && !inst.DoneInstall {
				inst.doFinalInstall()
			}
		}()

		spm.UpdateProgress(0, "Preparing to download...")

		// Define the package specifications.
		specs := []spm.AppIndexEntry{
			{
				Name:    "spitfire-luncher",
				Release: "nightly",
				OS:      runtime.GOOS,
				Arch:    runtime.GOARCH,
				Type:    "luncher",
			},
			{
				Name:    "spitfire-browser",
				Release: "nightly",
				OS:      runtime.GOOS,
				Arch:    runtime.GOARCH,
				Type:    "browser",
			},
		}

		spm.UpdateProgress(0, "Downloading specified packages...")
		if err := spm.AutoDownloadSpecified(specs); err != nil {
			fmt.Println("AutoDownloadSpecifiedPackages failed:", err)
			inst.LastError = err
			return
		}

		spm.UpdateProgress(0, "Download and decompression complete!")
		// Here, update your installer state so FinalInstall() can proceed.
		inst.DoneDownload = true
	}()
}

// FinalInstall is called by the UI to request installation.
// If download is done, it runs immediately, otherwise sets PendingInstall=true.
func (inst *Installer) FinalInstall() {
	// Already installed or installing => ignore repeated calls.
	if inst.IsInstalling || inst.DoneInstall {
		return
	}

	// If not done downloading, mark that we want to install once finished.
	if !inst.DoneDownload {
		fmt.Println("Cannot install now: download and decompression not complete -> pending install.")
		inst.PendingInstall = true
		return
	}

	// Otherwise, go ahead and install now.
	inst.doFinalInstall()
}

// doFinalInstall does the actual installation by invoking AutoInstallUpdates.
func (inst *Installer) doFinalInstall() {
	inst.IsInstalling = true
	inst.PendingInstall = false // we are fulfilling the install now

	go func() {
		defer func() {
			inst.IsInstalling = false
			inst.DoneInstall = (inst.LastError == nil)
		}()

		spm.UpdateProgress(0, "Installing updates...")
		if err := spm.AutoInstallUpdates(); err != nil {
			inst.LastError = err
			return
		}

		spm.UpdateProgress(100, "Installation complete!")
	}()
}

// PollProgress fetches the latest progress and task from SPM.
func (inst *Installer) PollProgress() {
	p, t := spm.GetProgress()
	inst.Progress, inst.Task = p, t
}