// Command server is the GitManager entrypoint. It wires config, logging, the
// Git boundary, the repo scanner, and the Echo HTTP server, then serves the
// dashboard shell and the JSON endpoints the web components fetch from.
package main

import (
	"context"
	"encoding/json"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"

	"gitmanager/internal/activity"
	"gitmanager/internal/config"
	"gitmanager/internal/git"
	"gitmanager/internal/logging"
	mcpserver "gitmanager/internal/mcp"
	"gitmanager/internal/render"
	"gitmanager/internal/repos"
	"gitmanager/internal/service"
)

func main() {
	cfg, err := config.Load()
	if err != nil {
		panic(err)
	}

	log, closer, err := logging.Setup(cfg.Dev, cfg.LogFile)
	if err != nil {
		panic(err)
	}
	if closer != nil {
		defer closer.Close()
	}

	g := git.New(cfg.GitBin)
	if v, err := g.Version(context.Background()); err != nil {
		log.Warn("git binary not usable — repo operations will fail", "bin", cfg.GitBin, "err", err)
	} else {
		log.Info("git detected", "version", v)
	}

	// Start the read-only scanner in the background.
	scanner := repos.NewScanner(g, log, cfg.RepoRoots, cfg.ScanMaxDepth, cfg.ScanIgnore, cfg.ScanInterval, cfg.ScanFetchEnabled)
	scanCtx, stopScan := context.WithCancel(context.Background())
	defer stopScan()
	go scanner.Run(scanCtx)
	log.Info("scanner started", "roots", cfg.RepoRoots, "interval", cfg.ScanInterval.String(), "fetch", cfg.ScanFetchEnabled)

	// Coordination state: active project + activity feed (§8.2).
	feed := activity.New(log, 200)

	// The one service layer both the HTTP API and the MCP server call (§1.7).
	svc := service.New(g, scanner.Index, feed)

	tmpl, err := render.New("web/templates")
	if err != nil {
		log.Error("failed to parse templates", "err", err)
		os.Exit(1)
	}

	e := echo.New()
	e.HideBanner = true
	e.Renderer = tmpl
	e.Use(middleware.Recover())
	e.Use(middleware.RequestID())

	// Static assets and component sources.
	e.Static("/static", "web/static")
	e.Static("/components", "components")

	// Page shells.
	e.GET("/", func(c echo.Context) error {
		return c.Render(http.StatusOK, "index.html", nil)
	})
	e.GET("/help", func(c echo.Context) error {
		return c.Render(http.StatusOK, "help.html", nil)
	})

	// JSON API — components self-fetch from here.
	e.GET("/healthz", func(c echo.Context) error {
		return c.JSON(http.StatusOK, map[string]string{"status": "ok"})
	})
	e.GET("/api/repos", func(c echo.Context) error {
		return c.JSON(http.StatusOK, svc.ListRepos())
	})
	e.GET("/api/repo", func(c echo.Context) error {
		// The service only serves details for an already-discovered repo — it
		// never runs git against an arbitrary caller-supplied path (§1.3).
		detail, ok := svc.RepoDetail(c.Request().Context(), c.QueryParam("path"))
		if !ok {
			return c.JSON(http.StatusNotFound, map[string]string{"error": "unknown repository"})
		}
		return c.JSON(http.StatusOK, detail)
	})

	// Active project + activity (§8.2).
	e.GET("/api/active-project", func(c echo.Context) error {
		return c.JSON(http.StatusOK, map[string]string{"path": svc.ActiveProject()})
	})
	e.POST("/api/active-project", func(c echo.Context) error {
		var body struct {
			Path string `json:"path"`
		}
		if err := c.Bind(&body); err != nil {
			return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid body"})
		}
		// A user action in the UI (actor=user) — distinct from Claude's own switches.
		if _, _, err := svc.SetActiveProject(activity.ActorUser, body.Path); err != nil {
			return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
		}
		return c.JSON(http.StatusOK, map[string]string{"path": svc.ActiveProject()})
	})
	e.GET("/api/activity", func(c echo.Context) error {
		return c.JSON(http.StatusOK, svc.Activity(0))
	})

	// Graceful handoff (§8.3): the user requests a switch; Claude completes it.
	e.GET("/api/switch", func(c echo.Context) error {
		p, ok := svc.PendingSwitch()
		if !ok {
			return c.JSON(http.StatusOK, map[string]any{"pending": false})
		}
		return c.JSON(http.StatusOK, map[string]any{
			"pending": true, "target": p.Target, "note": p.Note, "requestedAt": p.RequestedAt,
		})
	})
	e.POST("/api/switch", func(c echo.Context) error {
		var body struct {
			Target string `json:"target"`
			Note   string `json:"note"`
		}
		if err := c.Bind(&body); err != nil {
			return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid body"})
		}
		p, err := svc.RequestSwitch(activity.ActorUser, body.Target, body.Note)
		if err != nil {
			return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
		}
		return c.JSON(http.StatusOK, map[string]any{"pending": true, "target": p.Target, "note": p.Note})
	})
	e.DELETE("/api/switch", func(c echo.Context) error {
		svc.CancelSwitch(activity.ActorUser)
		return c.JSON(http.StatusOK, map[string]any{"pending": false})
	})

	// SSE stream of activity events for live UI (§8.2).
	e.GET("/events", func(c echo.Context) error {
		w := c.Response()
		w.Header().Set("Content-Type", "text/event-stream")
		w.Header().Set("Cache-Control", "no-cache")
		w.Header().Set("Connection", "keep-alive")
		w.WriteHeader(http.StatusOK)
		w.Flush()

		ch, unsub := svc.SubscribeActivity()
		defer unsub()

		keepalive := time.NewTicker(25 * time.Second)
		defer keepalive.Stop()

		for {
			select {
			case <-c.Request().Context().Done():
				return nil
			case <-keepalive.C:
				if _, err := w.Write([]byte(": ping\n\n")); err != nil {
					return nil
				}
				w.Flush()
			case ev := <-ch:
				data, err := json.Marshal(ev)
				if err != nil {
					continue
				}
				if _, err := w.Write([]byte("event: activity\ndata: " + string(data) + "\n\n")); err != nil {
					return nil
				}
				w.Flush()
			}
		}
	})

	// MCP server — Claude connects via the local stdio bridge (§8.1). Same
	// service layer as the HTTP API (§1.7); localhost-bound like everything else.
	mcpSrv := mcpserver.NewServer(svc, "0.1.0")
	e.Any("/mcp", echo.WrapHandler(mcpserver.Handler(mcpSrv)))
	log.Info("mcp server mounted", "path", "/mcp")

	// Serve with graceful shutdown.
	go func() {
		if err := e.Start(cfg.ListenAddr); err != nil && err != http.ErrServerClosed {
			log.Error("server error", "err", err)
			os.Exit(1)
		}
	}()
	log.Info("listening", "addr", cfg.ListenAddr)

	// Optional HTTPS listener (same Echo app). Required for the MCP connector,
	// which only accepts https:// URLs (§8.1). Best-effort: a missing/unreadable
	// cert logs a warning and leaves the app running over HTTP.
	if cfg.HTTPSAddr != "" && cfg.TLSCertFile != "" && cfg.TLSKeyFile != "" {
		if _, err := os.Stat(cfg.TLSCertFile); err != nil {
			log.Warn("HTTPS requested but cert not readable — serving HTTP only", "cert", cfg.TLSCertFile, "err", err)
		} else {
			go func() {
				if err := e.StartTLS(cfg.HTTPSAddr, cfg.TLSCertFile, cfg.TLSKeyFile); err != nil && err != http.ErrServerClosed {
					log.Error("TLS server error", "err", err)
				}
			}()
			log.Info("listening (https)", "addr", cfg.HTTPSAddr)
		}
	}

	quit := make(chan os.Signal, 1)
	signal.Notify(quit, os.Interrupt, syscall.SIGTERM)
	<-quit
	log.Info("shutting down")

	stopScan()
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	if err := e.Shutdown(ctx); err != nil {
		log.Error("graceful shutdown failed", "err", err)
	}
}