package main

import (
	"flag"
	"log"
	"os"
	"path/filepath"
	"sync"

	"gioui.org/app"
	"gioui.org/op"
	"gioui.org/text"
	"gioui.org/unit"
	"gioui.org/font/gofont"
	"gioui.org/io/key"
	"gioui.org/widget"

	"pad/internal/editor"
	"pad/internal/io/pool/real"
	"pad/internal/ui"
)

func main() {
	go func() {
		w := new(app.Window)
		w.Option(app.Title("Pad"))
		w.Option(app.Size(unit.Dp(390), unit.Dp(844)))
		if err := run(w); err != nil {
			log.Fatal(err)
		}
		os.Exit(0)
	}()
	app.Main()
}

func run(w *app.Window) error {
	log.Printf("run: starting")
	var ops op.Ops
	shaper := text.NewShaper(text.WithCollection(gofont.Collection()))

	// Determine root directory for real filesystem
	rootDir := flag.String("root", startpath, "root directory for the filesystem")
	flag.Parse()

	// Initialize the real filesystem rooted at the system root "/"
	// so that the browser can navigate the entire system.
	fs := real.NewRealFileSystem("/")
	
	// Get the absolute path of the startup directory
	startAbs, err := filepath.Abs(*rootDir)
	if err != nil {
		startAbs = *rootDir
	}
	log.Printf("using filesystem at / (startup directory: %s)", startAbs)

	logic := editor.NewLogic(fs, startAbs, OpenFile)
	renderer := ui.New(ui.Theme{FontSize: 14}, shaper)

	// The search bar's widget.Editor is owned by the MAIN goroutine: Gio
	// mutates it during draw, and the logic goroutine must never touch it
	// (architecture.md §1). Its text is forwarded to the logic goroutine via
	// SearchQueryChan; the logic only stores the result in Browser.Query.
	var searchEditor widget.Editor
	renderer.RegisterGioEditor("search_bar", &searchEditor)

	// frame is the frame-receiver-stored handoff (architecture.md §2.2/§9):
	// the ONLY data the main goroutine reads from the logic side.
	var mu sync.Mutex
	var frame editor.Frame

	log.Printf("run: starting frameReceiver")
	go frameReceiver(w, &mu, &frame, logic.FrameChan())
	log.Printf("run: starting logic.Run")
	go logic.Run()

	for {
		switch e := w.Event().(type) {
		case app.DestroyEvent:
			logic.Shutdown()
			return e.Err
		case app.ConfigEvent:
			// ConfigEvent: raw pixel dimensions only.
			logic.ConfigChan() <- editor.ConfigEvent{
				PixelWidth:  e.Config.Size.X,
				PixelHeight: e.Config.Size.Y,
			}
		case app.FrameEvent:
			gtx := app.NewContext(&ops, e)
			newScale := gtx.Metric.PxPerDp
			// Read ONLY the frame-receiver-stored snapshot; the main goroutine
			// never touches logic State (architecture.md §1).
			mu.Lock()
			curScale := frame.Scale
			if curScale <= 0 {
				curScale = 1 // no frame yet
			}
			renderer.Draw(gtx, frame.Elems, curScale)
			glyphLayout := renderer.GlyphLayout()
			// Send search query update to the logic goroutine when it changes.
			// The logic goroutine handles filtering and triggers a new frame.
			newQuery := searchEditor.Text()
			sendQuery := newQuery != frame.Query
			events := renderer.CheckGestures(e.Source, gtx.Metric)

			// Gather key events
			focusedID := frame.FocusedElementID
			if focusedID != "" {
				if reg, ok := renderer.Keys[focusedID]; ok {
					// Use key.Filter to only receive events destined for the focused element.
					// We need both Key events (for arrow keys) and Edit events (for text input).
					// In Gio, key.Filter covers key presses, while key.FocusFilter covers
					// focus and text edit events.
					for {
						// Filter for key events and focus/edit events targeted at focusedID
						evt, ok := gtx.Event(key.Filter{Focus: focusedID}, key.FocusFilter{Target: focusedID})
						if !ok {
							break
						}
						//log.Printf("found an event: %T", evt)
						switch k := evt.(type) {
						case key.Event:
							//log.Printf("key event: %v state=%v", k.Name, k.State)
							if k.State == key.Press {
								events = append(events, ui.InputEvent{
									Handler: reg.Handler,
									Data:    k.Name,
								})
							}
						case key.EditEvent:
							//log.Printf("edit event text: %q", k.Text)
							events = append(events, ui.InputEvent{
								Handler: reg.Handler,
								Data:    k,
							})
						case key.SnippetEvent:
							//log.Printf("snippet event: %v", k)
							// Handle snippet event if necessary, or ignore
						default:
							log.Printf("unexpected event type: %T", k)
						}
					}
				}
			}
			e.Frame(&ops)
			mu.Unlock()
			if newScale != curScale {
				logic.ConfigChan() <- editor.ScaleEvent{Scale: newScale}
			}
			if len(events) > 0 {
				logic.InputChan() <- events
			}
			if sendQuery {
				logic.SearchQueryChan() <- newQuery
			}
			logic.LayoutChan() <- glyphLayout
		default:
			//log.Printf("pad: default event")
			handleEvent(e)
		}
	}
}

func frameReceiver(w *app.Window, mu *sync.Mutex, frame *editor.Frame, frameChan <-chan editor.Frame) {
	log.Printf("frameReceiver: loop starting")
	for {
		f := <-frameChan
		//log.Printf("frameReceiver: received frame")
		mu.Lock()
		*frame = f
		w.Invalidate()
		mu.Unlock()
	}
}