package api

import (
	"crypto/rand"
	"encoding/hex"
	"errors"
	"log/slog"
	"net/http"

	"github.com/go-chi/chi/v5"

	"github.com/alexei/tinyforge/internal/store"
)

// generateWebhookSecret returns a 256-bit hex-encoded random token. Mirrors
// the helper in internal/store; kept here to avoid an import cycle and so the
// rotation handlers don't pretend to use uuid for what is really a secret.
func generateWebhookSecret() string {
	b := make([]byte, 32)
	if _, err := rand.Read(b); err != nil {
		panic("crypto/rand failed: " + err.Error())
	}
	return hex.EncodeToString(b)
}

// webhookURLResponse is the common payload returned by every webhook endpoint.
// Clients never see raw secrets except at issue/rotate time via these fields;
// the URL shape is "/api/webhook/..." so callers can prepend their own origin.
type webhookURLResponse struct {
	WebhookURL              string `json:"webhook_url"`
	WebhookSecret           string `json:"webhook_secret"`
	HasSigningSecret        bool   `json:"has_signing_secret"`
	WebhookRequireSignature bool   `json:"webhook_require_signature"`
}

// signingSecretResponse is returned when a signing secret is issued or rotated.
type signingSecretResponse struct {
	SigningSecret string `json:"signing_secret"`
}

// signingToggleRequest is the body of the require-signature toggle endpoint.
type signingToggleRequest struct {
	RequireSignature bool `json:"require_signature"`
}

// getProjectWebhook handles GET /api/projects/{id}/webhook.
// Returns the project's webhook URL + secret, generating one lazily if the
// project predates the per-project webhook migration.
func (s *Server) getProjectWebhook(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	secret, err := s.store.EnsureProjectWebhookSecret(id)
	if err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "project")
			return
		}
		slog.Error("get project webhook: ensure secret", "project", id, "error", err)
		respondError(w, http.StatusInternalServerError, "failed to get webhook secret")
		return
	}

	project, err := s.store.GetProjectByID(id)
	if err != nil {
		respondError(w, http.StatusInternalServerError, "failed to get project")
		return
	}

	respondJSON(w, http.StatusOK, webhookURLResponse{
		WebhookURL:              "/api/webhook/" + secret,
		WebhookSecret:           secret,
		HasSigningSecret:        project.WebhookSigningSecret != "",
		WebhookRequireSignature: project.WebhookRequireSignature,
	})
}

// regenerateProjectSigningSecret handles POST /api/projects/{id}/webhook/signing-secret/regenerate.
// Issues a fresh HMAC signing secret for inbound webhook verification. The
// secret is returned exactly once — the UI is responsible for letting the
// user copy it into their CI configuration.
func (s *Server) regenerateProjectSigningSecret(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if _, err := s.store.GetProjectByID(id); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "project")
			return
		}
		respondError(w, http.StatusInternalServerError, "failed to get project")
		return
	}
	secret := generateWebhookSecret()
	if err := s.store.SetProjectWebhookSigningSecret(id, secret); err != nil {
		slog.Error("rotate project signing secret", "project", id, "error", err)
		respondError(w, http.StatusInternalServerError, "failed to rotate signing secret")
		return
	}
	slog.Info("project webhook signing secret rotated", "project", id)
	respondJSON(w, http.StatusOK, signingSecretResponse{SigningSecret: secret})
}

// disableProjectSigningSecret handles DELETE /api/projects/{id}/webhook/signing-secret.
// Clears the HMAC signing secret and disables enforcement.
func (s *Server) disableProjectSigningSecret(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if err := s.store.SetProjectWebhookSigningSecret(id, ""); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "project")
			return
		}
		respondError(w, http.StatusInternalServerError, "failed to clear signing secret")
		return
	}
	if err := s.store.SetProjectWebhookRequireSignature(id, false); err != nil {
		slog.Warn("disable project require_signature", "project", id, "error", err)
	}
	respondJSON(w, http.StatusOK, map[string]bool{"success": true})
}

// updateProjectSigningRequirement handles PUT /api/projects/{id}/webhook/require-signature.
// Toggles whether unsigned/invalidly-signed inbound webhook requests are
// rejected with 401.
func (s *Server) updateProjectSigningRequirement(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	var req signingToggleRequest
	if !decodeJSON(w, r, &req) {
		return
	}
	if req.RequireSignature {
		project, err := s.store.GetProjectByID(id)
		if err != nil {
			if errors.Is(err, store.ErrNotFound) {
				respondNotFound(w, "project")
				return
			}
			respondError(w, http.StatusInternalServerError, "failed to get project")
			return
		}
		if project.WebhookSigningSecret == "" {
			respondError(w, http.StatusBadRequest, "issue a signing secret before enabling enforcement")
			return
		}
	}
	if err := s.store.SetProjectWebhookRequireSignature(id, req.RequireSignature); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "project")
			return
		}
		respondError(w, http.StatusInternalServerError, "failed to update setting")
		return
	}
	respondJSON(w, http.StatusOK, map[string]bool{"success": true})
}

// regenerateProjectWebhook handles POST /api/projects/{id}/webhook/regenerate.
// Rotates the project's webhook secret, invalidating the old URL.
func (s *Server) regenerateProjectWebhook(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	// Verify project exists before rotating.
	if _, err := s.store.GetProjectByID(id); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "project")
			return
		}
		slog.Error("regenerate project webhook: lookup", "project", id, "error", err)
		respondError(w, http.StatusInternalServerError, "failed to get project")
		return
	}

	secret := generateWebhookSecret()
	if err := s.store.SetProjectWebhookSecret(id, secret); err != nil {
		slog.Error("regenerate project webhook: set secret", "project", id, "error", err)
		respondError(w, http.StatusInternalServerError, "failed to rotate webhook secret")
		return
	}

	slog.Info("project webhook secret rotated", "project", id)
	respondJSON(w, http.StatusOK, webhookURLResponse{
		WebhookURL:    "/api/webhook/" + secret,
		WebhookSecret: secret,
	})
}

// getStaticSiteWebhook handles GET /api/sites/{id}/webhook.
func (s *Server) getStaticSiteWebhook(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	secret, err := s.store.EnsureStaticSiteWebhookSecret(id)
	if err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "static site")
			return
		}
		slog.Error("get site webhook: ensure secret", "site", id, "error", err)
		respondError(w, http.StatusInternalServerError, "failed to get webhook secret")
		return
	}

	site, err := s.store.GetStaticSiteByID(id)
	if err != nil {
		respondError(w, http.StatusInternalServerError, "failed to get static site")
		return
	}

	respondJSON(w, http.StatusOK, webhookURLResponse{
		WebhookURL:              "/api/webhook/sites/" + secret,
		WebhookSecret:           secret,
		HasSigningSecret:        site.WebhookSigningSecret != "",
		WebhookRequireSignature: site.WebhookRequireSignature,
	})
}

// regenerateStaticSiteSigningSecret handles POST /api/sites/{id}/webhook/signing-secret/regenerate.
func (s *Server) regenerateStaticSiteSigningSecret(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if _, err := s.store.GetStaticSiteByID(id); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "static site")
			return
		}
		respondError(w, http.StatusInternalServerError, "failed to get static site")
		return
	}
	secret := generateWebhookSecret()
	if err := s.store.SetStaticSiteWebhookSigningSecret(id, secret); err != nil {
		slog.Error("rotate site signing secret", "site", id, "error", err)
		respondError(w, http.StatusInternalServerError, "failed to rotate signing secret")
		return
	}
	slog.Info("static site webhook signing secret rotated", "site", id)
	respondJSON(w, http.StatusOK, signingSecretResponse{SigningSecret: secret})
}

// disableStaticSiteSigningSecret handles DELETE /api/sites/{id}/webhook/signing-secret.
func (s *Server) disableStaticSiteSigningSecret(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if err := s.store.SetStaticSiteWebhookSigningSecret(id, ""); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "static site")
			return
		}
		respondError(w, http.StatusInternalServerError, "failed to clear signing secret")
		return
	}
	if err := s.store.SetStaticSiteWebhookRequireSignature(id, false); err != nil {
		slog.Warn("disable site require_signature", "site", id, "error", err)
	}
	respondJSON(w, http.StatusOK, map[string]bool{"success": true})
}

// updateStaticSiteSigningRequirement handles PUT /api/sites/{id}/webhook/require-signature.
func (s *Server) updateStaticSiteSigningRequirement(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	var req signingToggleRequest
	if !decodeJSON(w, r, &req) {
		return
	}
	if req.RequireSignature {
		site, err := s.store.GetStaticSiteByID(id)
		if err != nil {
			if errors.Is(err, store.ErrNotFound) {
				respondNotFound(w, "static site")
				return
			}
			respondError(w, http.StatusInternalServerError, "failed to get static site")
			return
		}
		if site.WebhookSigningSecret == "" {
			respondError(w, http.StatusBadRequest, "issue a signing secret before enabling enforcement")
			return
		}
	}
	if err := s.store.SetStaticSiteWebhookRequireSignature(id, req.RequireSignature); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "static site")
			return
		}
		respondError(w, http.StatusInternalServerError, "failed to update setting")
		return
	}
	respondJSON(w, http.StatusOK, map[string]bool{"success": true})
}

// regenerateStaticSiteWebhook handles POST /api/sites/{id}/webhook/regenerate.
func (s *Server) regenerateStaticSiteWebhook(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	if _, err := s.store.GetStaticSiteByID(id); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "static site")
			return
		}
		slog.Error("regenerate site webhook: lookup", "site", id, "error", err)
		respondError(w, http.StatusInternalServerError, "failed to get static site")
		return
	}

	secret := generateWebhookSecret()
	if err := s.store.SetStaticSiteWebhookSecret(id, secret); err != nil {
		slog.Error("regenerate site webhook: set secret", "site", id, "error", err)
		respondError(w, http.StatusInternalServerError, "failed to rotate webhook secret")
		return
	}

	slog.Info("static site webhook secret rotated", "site", id)
	respondJSON(w, http.StatusOK, webhookURLResponse{
		WebhookURL:    "/api/webhook/sites/" + secret,
		WebhookSecret: secret,
	})
}