// Command keeld is the Keel daemon: it serves a local web UI and drives the
// harness — the general collect→brain→act loop that hosts one mode at a time
// (focus or offscreen).
package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"time"

	"keel/internal/ai"
	"keel/internal/aw"
	"keel/internal/enforce"
	"keel/internal/evidence"
	"keel/internal/harness"
	"keel/internal/knowledge"
	"keel/internal/memory"
	"keel/internal/mode"
	"keel/internal/mode/focus"
	"keel/internal/mode/offscreen"
	"keel/internal/settings"
	"keel/internal/statusfile"
	"keel/internal/tasks"
	"keel/internal/web"
)

const addr = "localhost:7777"

func main() {
	home, err := os.UserHomeDir()
	if err != nil {
		log.Fatalf("resolve home dir: %v", err)
	}
	root := filepath.Join(home, ".keel")

	// Resolve and load settings, seeding from the legacy KEEL_* env vars on
	// first run. After first run the file is the sole source of truth; env is
	// ignored. A missing file is the first-run signal.
	settingsPath, err := settings.DefaultPath()
	if err != nil {
		log.Fatalf("resolve settings path: %v", err)
	}
	cfg, err := settings.Load(settingsPath)
	if err != nil {
		cfg = settings.SeedFromEnv()
		if err := settings.Save(settingsPath, cfg); err != nil {
			log.Printf("settings: could not write %s (continuing): %v", settingsPath, err)
		} else {
			log.Printf("settings: seeded %s from environment", settingsPath)
		}
	}

	// buildServices turns a Settings value into a fresh harness.Services. It
	// validates the AI backend FIRST and returns an error before constructing any
	// ports, so an invalid backend never half-rewires the harness. The same code
	// path serves startup and live POST /settings edits.
	buildServices := func(s settings.Settings) (harness.Services, error) {
		backend, err := ai.NewBackend(s.AIBackend)
		if err != nil {
			return harness.Services{}, fmt.Errorf("%w: %v", settings.ErrInvalidBackend, err)
		}
		svc := ai.NewService(backend)

		// Defend against a hand-blanked aw_url: SeedFromEnv defaults this only on
		// first run, but Load returns whatever the JSON file holds on later starts.
		awURL := s.AWURL
		if awURL == "" {
			awURL = "http://localhost:5600"
		}
		var mem memory.Store = memory.NewNop()
		awc := aw.New(awURL)
		if err := awc.EnsureBucket(context.Background(), "keel.events", "keel.event", "keel"); err != nil {
			log.Printf("memory: AW unavailable at %s (%v); running without memory", awURL, err)
		} else {
			mem = memory.NewAWStore(awc, "keel.events")
			log.Printf("memory: keel.events ready at %s", awURL)
		}

		return harness.Services{
			AI:        svc,
			Tasks:     tasks.NewMarvin(s.MarvinCmd),
			Knowledge: knowledge.NewFileSource(s.KnowledgePath),
			Enforce:   enforce.NewGuard(),
			Memory:    mem,
			Clock:     time.Now,
		}, nil
	}

	// Build the base services at startup. A bad persisted backend should not be
	// fatal: fall back to claude (always valid), persist the correction, and retry.
	base, err := buildServices(cfg)
	if err != nil {
		log.Printf("settings: %v; falling back to claude backend", err)
		cfg.AIBackend = "claude"
		if err := settings.Save(settingsPath, cfg); err != nil {
			log.Printf("settings: could not persist claude fallback to %s: %v", settingsPath, err)
		}
		base, err = buildServices(cfg)
		if err != nil {
			log.Fatalf("settings: build failed even with claude: %v", err)
		}
	}
	log.Printf("settings: ai=%s, marvin=%q, knowledge=%q", cfg.AIBackend, cfg.MarvinCmd, cfg.KnowledgePath)
	log.Printf("enforce: window-minimize guard")

	// withDir namespaces a factory's persistence under ~/.keel/modes/<kind>; the
	// mode builds its own file paths under Services.Dir.
	withDir := func(dir string, f harness.Factory) harness.Factory {
		return func(s harness.Services) mode.Mode {
			s.Dir = dir
			return f(s)
		}
	}

	focusDir := filepath.Join(root, "modes", "focus")
	offscreenDir := filepath.Join(root, "modes", "offscreen")
	h := harness.New(base, map[string]harness.Factory{
		"focus":     withDir(focusDir, focus.Factory),
		"offscreen": withDir(offscreenDir, offscreen.Factory),
	})

	// Re-adopt a live focus session restored from disk, if one was in flight.
	// Use h.Services() (Notify wired) rather than base (Notify nil) so the
	// restored mode's async completions reach the harness's onChange listeners.
	focusSvc := h.Services()
	focusSvc.Dir = focusDir
	if m, live, err := focus.Restore(focusSvc); err != nil {
		log.Printf("focus: restore failed (continuing idle): %v", err)
	} else if live {
		if err := h.Adopt(m); err != nil {
			log.Printf("focus: adopt restored session failed: %v", err)
		} else {
			log.Printf("focus: restored a live session")
		}
	}

	srv := web.NewServer(h)
	srv.Init() // re-arm or expire a restored deadline-bearing session

	// applyFn re-wires the running daemon from a new Settings value: it rebuilds a
	// fresh harness.Services and installs it via SetServices. Per the harness
	// contract this affects the NEXT mode start; an already-active mode keeps the
	// services it was built with. It validates the backend before mutating, so
	// POST /settings can reject an invalid backend atomically.
	applyFn := func(s settings.Settings) error {
		next, err := buildServices(s)
		if err != nil {
			return err
		}
		h.SetServices(next)
		return nil
	}
	srv.SetSettings(settingsPath, cfg, applyFn)

	// Mirror runtime status to ~/.keel_status for a window-manager bar.
	// A misconfigured home dir degrades to no status file, not a failed start.
	if statusPath, err := statusfile.DefaultPath(); err != nil {
		log.Printf("status file disabled: %v", err)
	} else {
		writer := statusfile.NewWriter(statusPath, h.State)
		// Re-render the bar on every harness change, not just the coarse tick, so a
		// drift transition reaches the status bar as fast as it reaches the web UI.
		h.AddOnChange(writer.Wake)
		go writer.Run(context.Background())
		log.Printf("status: writing %s", statusPath)
	}

	// Feed the window sensor stream into the harness, which forwards it to the
	// active mode iff that mode consumes evidence. On a headless box the source is
	// a no-op, so this degrades gracefully without new X11 requirements.
	src := evidence.NewSource()
	go src.Watch(context.Background(), h.RecordWindow)

	go openBrowser("http://" + addr)

	log.Printf("keeld listening on http://%s", addr)
	if err := srv.Router().Run(addr); err != nil {
		log.Fatalf("server: %v", err)
	}
}

// openBrowser best-effort launches the default browser after a short delay so
// the server is listening first. Failures are logged, not fatal.
func openBrowser(url string) {
	time.Sleep(300 * time.Millisecond)
	var cmd string
	var args []string
	switch runtime.GOOS {
	case "linux":
		cmd, args = "xdg-open", []string{url}
	case "darwin":
		cmd, args = "open", []string{url}
	case "windows":
		cmd, args = "rundll32", []string{"url.dll,FileProtocolHandler", url}
	default:
		log.Printf("open browser manually: %s", url)
		return
	}
	if err := exec.Command(cmd, args...).Start(); err != nil {
		log.Printf("could not open browser (%v); visit %s", err, url)
	}
}