package app

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"net/http"
	"time"

	"git.warky.dev/wdevs/amcs/internal/ai"
	"git.warky.dev/wdevs/amcs/internal/auth"
	"git.warky.dev/wdevs/amcs/internal/config"
	"git.warky.dev/wdevs/amcs/internal/mcpserver"
	"git.warky.dev/wdevs/amcs/internal/observability"
	"git.warky.dev/wdevs/amcs/internal/session"
	"git.warky.dev/wdevs/amcs/internal/store"
	"git.warky.dev/wdevs/amcs/internal/tools"
)

func Run(ctx context.Context, configPath string) error {
	cfg, loadedFrom, err := config.Load(configPath)
	if err != nil {
		return err
	}

	logger, err := observability.NewLogger(cfg.Logging)
	if err != nil {
		return err
	}

	logger.Info("loaded configuration",
		slog.String("path", loadedFrom),
		slog.String("provider", cfg.AI.Provider),
	)

	db, err := store.New(ctx, cfg.Database)
	if err != nil {
		return err
	}
	defer db.Close()

	if err := db.VerifyRequirements(ctx); err != nil {
		return err
	}

	httpClient := &http.Client{Timeout: 30 * time.Second}
	provider, err := ai.NewProvider(cfg.AI, httpClient, logger)
	if err != nil {
		return err
	}

	keyring, err := auth.NewKeyring(cfg.Auth.Keys)
	if err != nil {
		return err
	}
	activeProjects := session.NewActiveProjects()

	logger.Info("database connection verified",
		slog.String("provider", provider.Name()),
	)

	server := &http.Server{
		Addr:         fmt.Sprintf("%s:%d", cfg.Server.Host, cfg.Server.Port),
		Handler:      routes(logger, cfg, db, provider, keyring, activeProjects),
		ReadTimeout:  cfg.Server.ReadTimeout,
		WriteTimeout: cfg.Server.WriteTimeout,
		IdleTimeout:  cfg.Server.IdleTimeout,
	}

	errCh := make(chan error, 1)
	go func() {
		logger.Info("starting HTTP server",
			slog.String("addr", server.Addr),
			slog.String("mcp_path", cfg.MCP.Path),
		)

		if err := server.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			errCh <- err
		}
	}()

	select {
	case <-ctx.Done():
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()

		logger.Info("shutting down HTTP server")
		return server.Shutdown(shutdownCtx)
	case err := <-errCh:
		return fmt.Errorf("run server: %w", err)
	}
}

func routes(logger *slog.Logger, cfg *config.Config, db *store.DB, provider ai.Provider, keyring *auth.Keyring, activeProjects *session.ActiveProjects) http.Handler {
	mux := http.NewServeMux()

	toolSet := mcpserver.ToolSet{
		Capture:   tools.NewCaptureTool(db, provider, cfg.Capture, activeProjects, logger),
		Search:    tools.NewSearchTool(db, provider, cfg.Search, activeProjects),
		List:      tools.NewListTool(db, cfg.Search, activeProjects),
		Stats:     tools.NewStatsTool(db),
		Get:       tools.NewGetTool(db),
		Update:    tools.NewUpdateTool(db, provider, cfg.Capture, logger),
		Delete:    tools.NewDeleteTool(db),
		Archive:   tools.NewArchiveTool(db),
		Projects:  tools.NewProjectsTool(db, activeProjects),
		Context:   tools.NewContextTool(db, provider, cfg.Search, activeProjects),
		Recall:    tools.NewRecallTool(db, provider, cfg.Search, activeProjects),
		Summarize: tools.NewSummarizeTool(db, provider, cfg.Search, activeProjects),
		Links:     tools.NewLinksTool(db, provider, cfg.Search),
	}

	mcpHandler := mcpserver.New(cfg.MCP, toolSet)
	mux.Handle(cfg.MCP.Path, auth.Middleware(cfg.Auth, keyring, logger)(mcpHandler))
	mux.HandleFunc("/favicon.ico", serveFavicon)

	mux.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte("ok"))
	})

	mux.HandleFunc("/readyz", func(w http.ResponseWriter, r *http.Request) {
		if err := db.Ready(r.Context()); err != nil {
			logger.Error("readiness check failed", slog.String("error", err.Error()))
			http.Error(w, "not ready", http.StatusServiceUnavailable)
			return
		}

		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte("ready"))
	})

	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte("amcs is running"))
	})

	return observability.Chain(
		mux,
		observability.RequestID(),
		observability.Recover(logger),
		observability.AccessLog(logger),
		observability.Timeout(cfg.Server.WriteTimeout),
	)
}