// Copyright 2026 Versity Software
// This file is licensed under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package iamapi

import (
	"net/http"

	"github.com/gofiber/fiber/v3"
	"github.com/versity/versitygw/iamapi/iamerr"
	"github.com/versity/versitygw/iamapi/internal/iammiddleware"
	"github.com/versity/versitygw/iamapi/internal/iamutil"
	"github.com/versity/versitygw/iamapi/storage"
	"github.com/versity/versitygw/internal/sigv4auth"
)

const (
	iamAPIVersion                   = "2010-05-08"
	stsAPIVersion                   = "2011-06-15"
	noVersionSpecified              = "NO_VERSION_SPECIFIED"
	productURL                      = "https://www.versity.com/products/versitygw/"
	actionAssumeRoleWithWebIdentity = "AssumeRoleWithWebIdentity"
)

// stsActions are routed through this same IAM endpoint but, being real STS
// actions, are versioned against stsAPIVersion rather than iamAPIVersion —
// and (see response.go's ProcessController) render under STS's own XML
// namespace rather than IAM's.
var stsActions = map[string]bool{
	"AssumeRoleWithWebIdentity": true,
	"GetCallerIdentity":         true,
}

var unknownOperationBody = []byte("<UnknownOperationException/>\n")

type IAMApiRouter struct {
	app       *fiber.App
	store     storage.Storer
	Ctrl      IAMApiController
	actions   map[string]ActionHandler
	rootCreds *RootCredentials
	// oidcThumbprintAutoFetchDisabled is threaded into the controller;
	// see IAMApiController.oidcThumbprintAutoFetchDisabled.
	oidcThumbprintAutoFetchDisabled bool
}

func (r *IAMApiRouter) Init() {
	r.Ctrl = NewController(r.store, r.oidcThumbprintAutoFetchDisabled)

	r.actions = map[string]ActionHandler{
		// User CRUD
		"CreateUser": r.Ctrl.CreateUser,
		"DeleteUser": r.Ctrl.DeleteUser,
		"GetUser":    r.Ctrl.GetUser,
		"ListUsers":  r.Ctrl.ListUsers,
		"UpdateUser": r.Ctrl.UpdateUser,
		// User Access Key CRUD
		"CreateAccessKey":      r.Ctrl.CreateAccessKey,
		"UpdateAccessKey":      r.Ctrl.UpdateAccessKey,
		"DeleteAccessKey":      r.Ctrl.DeleteAccessKey,
		"GetAccessKeyLastUsed": r.Ctrl.GetAccessKeyLastUsed,
		"ListAccessKeys":       r.Ctrl.ListAccessKeys,
		// User Inline Policy CRUD
		"PutUserPolicy":    r.Ctrl.PutUserPolicy,
		"GetUserPolicy":    r.Ctrl.GetUserPolicy,
		"DeleteUserPolicy": r.Ctrl.DeleteUserPolicy,
		"ListUserPolicies": r.Ctrl.ListUserPolicies,
		// Role CRUD
		"CreateRole":             r.Ctrl.CreateRole,
		"GetRole":                r.Ctrl.GetRole,
		"ListRoles":              r.Ctrl.ListRoles,
		"DeleteRole":             r.Ctrl.DeleteRole,
		"UpdateAssumeRolePolicy": r.Ctrl.UpdateAssumeRolePolicy,
		// Role Inline Policy CRUD
		"PutRolePolicy":    r.Ctrl.PutRolePolicy,
		"GetRolePolicy":    r.Ctrl.GetRolePolicy,
		"DeleteRolePolicy": r.Ctrl.DeleteRolePolicy,
		"ListRolePolicies": r.Ctrl.ListRolePolicies,
		// OIDC Provider CRUD
		"CreateOpenIDConnectProvider":             r.Ctrl.CreateOpenIDConnectProvider,
		"GetOpenIDConnectProvider":                r.Ctrl.GetOpenIDConnectProvider,
		"ListOpenIDConnectProviders":              r.Ctrl.ListOpenIDConnectProviders,
		"DeleteOpenIDConnectProvider":             r.Ctrl.DeleteOpenIDConnectProvider,
		"AddClientIDToOpenIDConnectProvider":      r.Ctrl.AddClientIDToOpenIDConnectProvider,
		"RemoveClientIDFromOpenIDConnectProvider": r.Ctrl.RemoveClientIDFromOpenIDConnectProvider,
		"UpdateOpenIDConnectProviderThumbprint":   r.Ctrl.UpdateOpenIDConnectProviderThumbprint,
		// STS actions (routed through this same endpoint; see stsActions)
		"AssumeRoleWithWebIdentity": r.Ctrl.AssumeRoleWithWebIdentity,
		"GetCallerIdentity":         r.Ctrl.GetCallerIdentity,
	}

	iamRoute := ProcessHandlers(r.routeAction,
		iammiddleware.VerifyIAMAuth(sigv4auth.ServiceIAM, r.rootCreds, r.store),
		iammiddleware.VerifyIAMPolicy(r.store),
	)
	stsAuthRoute := ProcessHandlers(r.routeAction,
		iammiddleware.VerifyIAMAuth(sigv4auth.ServiceSTS, r.rootCreds, r.store),
	)
	stsOpenRoute := ProcessHandlers(r.routeAction)

	dispatch := func(ctx fiber.Ctx) error {
		action, _ := iamutil.RequestParam(ctx, "Action")
		switch {
		case action == actionAssumeRoleWithWebIdentity:
			return stsOpenRoute(ctx)
		case stsActions[action]:
			return stsAuthRoute(ctx)
		default:
			return iamRoute(ctx)
		}
	}

	r.app.Get("/*", iamutil.MatchQueryOrFormArgs("Action"), dispatch)
	r.app.Post("/*", iamutil.MatchQueryOrFormArgs("Action"), dispatch)

	r.app.All("/", r.redirectRoot)
	r.app.All("*", r.unknownOperation)
}

func (r *IAMApiRouter) routeAction(ctx fiber.Ctx) (*Response, error) {
	action, _ := iamutil.RequestParam(ctx, "Action")
	version, versionSpecified := iamutil.RequestParam(ctx, "Version")
	if !versionSpecified {
		version = noVersionSpecified
	}

	expectedVersion := iamAPIVersion
	if stsActions[action] {
		expectedVersion = stsAPIVersion
	}
	if version != expectedVersion {
		return &Response{}, iamerr.InvalidAction(action, version)
	}

	handler, ok := r.actions[action]
	if !ok {
		return &Response{}, iamerr.InvalidAction(action, version)
	}

	return handler(ctx)
}

func (r *IAMApiRouter) redirectRoot(ctx fiber.Ctx) error {
	iammiddleware.EnsureRequestID(ctx)
	ctx.Set(fiber.HeaderLocation, productURL)
	ctx.Status(http.StatusFound)
	return nil
}

func (r *IAMApiRouter) unknownOperation(ctx fiber.Ctx) error {
	iammiddleware.EnsureRequestID(ctx)
	return ctx.Status(http.StatusNotFound).Send(unknownOperationBody)
}