pansy/internal/api/api.go

// Package api wires pansy's HTTP surface: a gin engine with structured logging
// and panic recovery, the versioned JSON API under /api/v1, and (via spa.go) the
// embedded single-page-app fallback. Handlers stay thin — decode, call the
// service layer, encode — so all business logic and permission checks live in
// internal/service (added by later issues).
package api

import (
	"log/slog"
	"net/http"

	"github.com/gin-gonic/gin"
	sloggin "github.com/samber/slog-gin"

	"gitea.stevedudenhoeffer.com/steve/pansy/internal/agent"
	"gitea.stevedudenhoeffer.com/steve/pansy/internal/config"
	"gitea.stevedudenhoeffer.com/steve/pansy/internal/service"
)

// handlers carries the dependencies shared by every HTTP handler. Handlers stay
// thin: decode the request, call a service method, encode the result.
type handlers struct {
	cfg  *config.Config
	svc  *service.Service
	oidc *oidcClient // nil unless OIDC is configured (see config.OIDCReady)
	// agent is nil unless the assistant is configured; the chat routes are only
	// registered when it isn't, so a handler never has to check.
	agent *agent.Runner
}

// New builds the gin engine with the standard middleware stack and registers the
// API routes against the given service. The embedded SPA fallback is registered
// separately by the caller via RegisterSPA (see spa.go) so the API can be built
// and tested without a web build present.
func New(cfg *config.Config, svc *service.Service) *gin.Engine {
	gin.SetMode(gin.ReleaseMode)

	r := gin.New()
	r.Use(sloggin.New(slog.Default()), gin.Recovery())

	if err := r.SetTrustedProxies(cfg.TrustedProxies); err != nil {
		// Do not leave gin's trust-everyone default active on a parse failure —
		// that would let any client spoof X-Forwarded-For. Fall back to trusting
		// no proxies, which is also the behavior when none are configured.
		slog.Error("api: invalid trusted proxies, trusting none", "error", err)
		_ = r.SetTrustedProxies(nil)
	}

	h := &handlers{cfg: cfg, svc: svc}

	v1 := r.Group("/api/v1")
	// CSRF defense for every state-changing API call (no-op unless PANSY_BASE_URL
	// is set; see csrfGuard).
	v1.Use(h.csrfGuard())
	v1.GET("/healthz", healthz)
	// What this instance can actually do, so the UI offers only what works. The
	// agent routes 404 when unconfigured; without this the client would have to
	// probe for a 404 to find that out, and a dead button is worse than no button.
	v1.GET("/capabilities", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"agent": cfg.Agent.Ready()})
	})

	// Auth endpoints are exempt from requireAuth (you can't be logged in yet);
	// /me is the one that needs a session. Feature routers in later issues attach
	// h.requireAuth() to their own protected groups.
	auth := v1.Group("/auth")
	auth.POST("/register", h.register)
	auth.POST("/login", h.login)
	auth.POST("/logout", h.logout)
	auth.GET("/providers", h.providers)
	auth.GET("/me", h.requireAuth(), h.me)

	// OIDC routes exist only when OIDC can actually be offered, so an unconfigured
	// instance 404s them (matching what /auth/providers advertises). Provider
	// discovery is lazy (first request), so a briefly-unreachable IdP doesn't stop
	// the server — or local auth — from starting.
	switch {
	case cfg.OIDCReady():
		h.oidc = newOIDCClient(cfg)
		auth.GET("/oidc/login", h.oidcLogin)
		auth.GET("/oidc/callback", h.oidcCallback)
	case cfg.OIDC.Enabled():
		slog.Warn("api: OIDC is configured but PANSY_BASE_URL is unset; OIDC disabled (an absolute redirect URI is required)")
	}

	// Feature resources sit behind requireAuth, which resolves the session cookie
	// to the actor the service layer's permission checks key off.
	gardens := v1.Group("/gardens", h.requireAuth())
	gardens.GET("", h.listGardens)
	gardens.POST("", h.createGarden)
	gardens.GET("/:id", h.getGarden)
	gardens.PATCH("/:id", h.updateGarden)
	gardens.DELETE("/:id", h.deleteGarden)
	gardens.POST("/:id/copy", h.copyGarden)         // duplicate a garden the actor owns
	gardens.GET("/:id/full", h.getGardenFull)       // one-shot editor load
	gardens.GET("/:id/history", h.getGardenHistory) // change sets, newest first
	gardens.GET("/:id/years", h.getGardenYears)     // years with planting data
	gardens.POST("/:id/objects", h.createObject)
	// The grow journal hangs off a garden even for entries about one bed or one
	// plop, so it inherits the ordinary garden-role check.
	gardens.GET("/:id/journal", h.listJournal)
	gardens.POST("/:id/journal", h.createJournalEntry)
	gardens.GET("/:id/journal/counts", h.getJournalCounts)

	// Sharing (owner-managed; a recipient may remove their own share).
	gardens.GET("/:id/shares", h.listShares)
	gardens.POST("/:id/shares", h.addShare)
	gardens.PATCH("/:id/shares/:userId", h.updateShare)
	gardens.DELETE("/:id/shares/:userId", h.removeShare)

	// Public read-only share link (owner-managed): GET reports state, POST
	// enables/rotates, DELETE disables. The link itself is served unauthenticated
	// below.
	gardens.GET("/:id/share-link", h.getShareLink)
	gardens.POST("/:id/share-link", h.createShareLink)
	gardens.DELETE("/:id/share-link", h.deleteShareLink)

	// Objects are addressed by their own id; the service resolves the owning
	// garden for the permission check.
	objects := v1.Group("/objects", h.requireAuth())
	objects.PATCH("/:id", h.updateObject)
	objects.DELETE("/:id", h.deleteObject)
	objects.POST("/:id/plantings", h.createPlanting) // place a plop in this object

	// Plantings ("plops") are addressed by their own id; the service resolves the
	// owning object/garden for the permission check.
	plantings := v1.Group("/plantings", h.requireAuth())
	plantings.PATCH("/:id", h.updatePlanting)
	plantings.DELETE("/:id", h.deletePlanting)

	// The garden assistant, registered only when it can actually be offered —
	// the same shape as OIDC. An instance with no API key serves the app
	// normally and simply doesn't have these routes.
	if cfg.Agent.Ready() {
		runner, err := agent.NewRunner(svc, cfg)
		if err != nil {
			// Configured but unusable (an unresolvable model spec, say). Log it and
			// carry on without the assistant rather than refusing to start: a
			// garden planner that won't boot because of a chat feature is worse
			// than one without chat.
			slog.Error("api: garden assistant disabled", "error", err)
		} else {
			h.agent = runner
			agentGroup := v1.Group("/agent", h.requireAuth())
			agentGroup.POST("/chat", h.agentChat)
			gardens.GET("/:id/agent/history", h.getAgentHistory)
			gardens.DELETE("/:id/agent/history", h.deleteAgentHistory)
			slog.Info("api: garden assistant enabled", "model", cfg.Agent.Model)
		}
	}

	// Undo. A change set is addressed by its own id; the service resolves the
	// owning garden for the permission check, same as objects and plantings.
	changeSets := v1.Group("/change-sets", h.requireAuth())
	changeSets.POST("/:id/revert", h.revertChangeSet)

	// Journal entries are addressed by their own id; the service resolves the
	// owning garden for the permission check, same as objects and plantings.
	journal := v1.Group("/journal", h.requireAuth())
	journal.PATCH("/:id", h.updateJournalEntry)
	journal.DELETE("/:id", h.deleteJournalEntry)

	// Plant catalog: built-ins (seeded, read-only) plus the actor's own rows.
	plants := v1.Group("/plants", h.requireAuth())
	plants.GET("", h.listPlants)
	plants.POST("", h.createPlant)
	plants.PATCH("/:id", h.updatePlant)
	plants.DELETE("/:id", h.deletePlant)

	// Seed lots: what the actor bought, and what's left. Private to the buyer,
	// so these hang off the session actor rather than off a garden.
	seedLots := v1.Group("/seed-lots", h.requireAuth())
	seedLots.GET("", h.listSeedLots)
	seedLots.POST("", h.createSeedLot)
	seedLots.GET("/:id", h.getSeedLot)
	seedLots.PATCH("/:id", h.updateSeedLot)
	seedLots.DELETE("/:id", h.deleteSeedLot)

	// Public, unauthenticated read of a garden by its share token. Deliberately
	// NOT behind requireAuth: the token is the capability, so a logged-out visitor
	// opens a shared link without being redirected to /login or OIDC. Only GET,
	// only the read-only /full payload — never a mutation.
	public := v1.Group("/public")
	public.GET("/gardens/:token", h.getPublicGarden)

	return r
}

// healthz is a liveness probe: always returns {"ok": true} when the server is up.
func healthz(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{"ok": true})
}