// Command antidriftd is the AntiDrift focus daemon: it serves a local web UI
// and owns the commitment state machine.
package main

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

	"antidrift/internal/ai"
	"antidrift/internal/enforce"
	"antidrift/internal/evidence"
	"antidrift/internal/knowledge"
	"antidrift/internal/session"
	"antidrift/internal/settings"
	"antidrift/internal/statusfile"
	"antidrift/internal/store"
	"antidrift/internal/tasks"
	"antidrift/internal/web"
)

const addr = "localhost:7777"

func main() {
	path, err := store.DefaultPath()
	if err != nil {
		log.Fatalf("resolve snapshot path: %v", err)
	}
	ctrl, err := session.New(path)
	if err != nil {
		log.Fatalf("load session: %v", err)
	}

	srv := web.NewServer(ctrl)
	srv.Init() // re-arm or expire a restored Active session

	// Resolve and load settings, seeding from the legacy ANTIDRIFT_* 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)
		}
	}

	// The knowledge source is a single file adapter whose path is driven entirely
	// by SetKnowledgePath, so startup and live settings edits share one code path.
	ctrl.SetKnowledge(knowledge.NewFileSource(""))

	// applyFn re-wires the running daemon from a Settings value: AI backend +
	// service (coach/drift/nudge/reviewer), tasks command, and knowledge path. It
	// validates the backend FIRST and mutates nothing on failure, so POST /settings
	// can reject an invalid backend atomically.
	applyFn := func(s settings.Settings) error {
		backend, err := ai.NewBackend(s.AIBackend)
		if err != nil {
			return fmt.Errorf("%w: %v", settings.ErrInvalidBackend, err)
		}
		svc := ai.NewService(backend)
		ctrl.SetCoach(svc)
		ctrl.SetDriftJudge(svc)
		ctrl.SetNudge(svc)
		ctrl.SetReviewer(svc)
		ctrl.SetTasks(tasks.NewMarvin(s.MarvinCmd))
		ctrl.SetKnowledgePath(s.KnowledgePath)
		return nil
	}

	// Apply once at startup. A bad persisted backend should not be fatal: fall back
	// to claude (always valid), persist the correction, and re-apply.
	if err := applyFn(cfg); 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)
		}
		if err := applyFn(cfg); err != nil {
			log.Fatalf("settings: apply failed even with claude: %v", err)
		}
	}
	srv.SetSettings(settingsPath, cfg, applyFn)
	log.Printf("settings: ai=%s, marvin=%q, knowledge=%q", cfg.AIBackend, cfg.MarvinCmd, cfg.KnowledgePath)

	// Mirror runtime status to ~/.antidrift_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 {
		go statusfile.NewWriter(statusPath, ctrl.State).Run(context.Background())
		log.Printf("status: writing %s", statusPath)
	}

	ctrl.SetGuard(enforce.NewGuard())
	log.Printf("enforce: window-minimize guard")

	src := evidence.NewSource()
	go src.Watch(context.Background(), ctrl.RecordWindow)

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

	log.Printf("antidriftd 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)
	}
}