// 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 (
	"errors"
	"fmt"
	"time"

	"github.com/gofiber/fiber/v3"
	"github.com/versity/versitygw/debuglogger"
	"github.com/versity/versitygw/iamapi/iamerr"
	"github.com/versity/versitygw/iamapi/internal/iamutil"
	"github.com/versity/versitygw/iamapi/policy"
	"github.com/versity/versitygw/iamapi/storage"
	"github.com/versity/versitygw/iamapi/types"
)

type IAMApiController struct {
	store storage.Storer
}

func NewController(store storage.Storer) IAMApiController {
	return IAMApiController{store: store}
}

func (c IAMApiController) CreateUser(ctx fiber.Ctx) (*Response, error) {
	userName, err := iamutil.GetUserName(ctx, "CreateUser", iamutil.MaxUserNameLen, iamerr.MissingValue("userName"))
	if err != nil {
		return nil, err
	}

	path, ok := iamutil.RequestParam(ctx, "Path")
	if !ok || path == "" {
		path = iamutil.DefaultUserPath
	}
	if err := iamutil.ValidatePath("path", path); err != nil {
		return nil, err
	}

	tags, err := iamutil.ParseTags(ctx)
	if err != nil {
		return nil, err
	}

	for range 3 {
		userID, err := iamutil.GenerateUserID()
		if err != nil {
			return nil, err
		}

		user := types.User{
			Path:       path,
			UserName:   userName,
			UserID:     userID,
			Arn:        iamutil.BuildUserArn(iamutil.DefaultAccountID, path, userName),
			CreateDate: time.Now().UTC().Truncate(time.Second),
			Tags:       tags,
		}

		stored, err := c.store.CreateUser(ctx.Context(), user)
		if errors.Is(err, storage.ErrUserIDAlreadyExists) {
			debuglogger.Logf("IAM user ID collision while creating user %q: %v", userName, err)
			continue
		}
		if err != nil {
			debuglogger.Logf("failed to create IAM user %q: %v", userName, err)
			return nil, err
		}

		return &Response{Data: &types.CreateUserResponse{
			Result: types.CreateUserResult{User: *stored},
		}}, nil
	}

	err = fmt.Errorf("generate IAM user id: exhausted collision retries")
	debuglogger.Logf("failed to create IAM user %q: %v", userName, err)
	return nil, err
}

func (c IAMApiController) DeleteUser(ctx fiber.Ctx) (*Response, error) {
	username, err := iamutil.GetUserName(ctx, "DeleteUser", iamutil.MaxUserLookupLen, iamerr.MissingParameter("UserName"))
	if err != nil {
		return nil, err
	}

	if err := c.store.DeleteUser(ctx.Context(), username); err != nil {
		debuglogger.Logf("failed to delete IAM user %q: %v", username, err)
		return nil, err
	}

	return &Response{Data: &types.DeleteUserResponse{}}, nil
}

func (c IAMApiController) GetUser(ctx fiber.Ctx) (*Response, error) {
	username, ok := iamutil.RequestParam(ctx, "UserName")
	if !ok {
		debuglogger.Logf("missing required GetUser parameter: UserName")
		return nil, iamerr.MissingParameter("UserName")
	}
	if username == "" {
		return &Response{Data: &types.GetUserResponse{
			Result: types.GetUserResult{User: types.User{
				UserID: iamutil.DefaultAccountID,
				Arn:    fmt.Sprintf("arn:aws:iam::%s:root", iamutil.DefaultAccountID),
			}},
		}}, nil
	}
	if err := iamutil.ValidateName("userName", username, iamutil.MaxUserLookupLen); err != nil {
		return nil, err
	}

	user, err := c.store.GetUser(ctx.Context(), username)
	if err != nil {
		debuglogger.Logf("failed to get IAM user %q: %v", username, err)
		return nil, err
	}

	return &Response{Data: &types.GetUserResponse{
		Result: types.GetUserResult{User: *user},
	}}, nil
}

func (c IAMApiController) ListUsers(ctx fiber.Ctx) (*Response, error) {
	pathPrefix, ok := iamutil.RequestParam(ctx, "PathPrefix")
	if !ok || pathPrefix == "" {
		pathPrefix = iamutil.DefaultUserPath
	}
	if err := iamutil.ValidatePathPrefix(pathPrefix); err != nil {
		return nil, err
	}

	maxItems, err := iamutil.ParseMaxItems(ctx, "ListUsers")
	if err != nil {
		return nil, err
	}

	marker, _ := iamutil.RequestParam(ctx, "Marker")
	out, err := c.store.ListUsers(ctx.Context(), storage.ListUsersInput{
		PathPrefix: pathPrefix,
		Marker:     marker,
		MaxItems:   maxItems,
	})
	if err != nil {
		debuglogger.Logf("failed to list IAM users: %v", err)
		return nil, err
	}

	return &Response{Data: &types.ListUsersResponse{
		Result: types.ListUsersResult{
			Users:       types.Users{Members: out.Users},
			IsTruncated: out.IsTruncated,
			Marker:      out.Marker,
		},
	}}, nil
}

func (c IAMApiController) UpdateUser(ctx fiber.Ctx) (*Response, error) {
	username, err := iamutil.GetUserName(ctx, "UpdateUser", iamutil.MaxUserLookupLen, iamerr.MissingParameter("UserName"))
	if err != nil {
		return nil, err
	}

	newPath, _ := iamutil.RequestParam(ctx, "NewPath")
	if newPath != "" {
		if err := iamutil.ValidatePath("newPath", newPath); err != nil {
			return nil, err
		}
	}
	newUserName, _ := iamutil.RequestParam(ctx, "NewUserName")
	if newUserName != "" {
		if err := iamutil.ValidateName("newUserName", newUserName, iamutil.MaxUserNameLen); err != nil {
			return nil, err
		}
	}

	user, err := c.store.GetUser(ctx.Context(), username)
	if err != nil {
		debuglogger.Logf("failed to get IAM user %q for update: %v", username, err)
		return nil, err
	}

	finalPath := user.Path
	if newPath != "" {
		finalPath = newPath
	}
	finalUserName := user.UserName
	if newUserName != "" {
		finalUserName = newUserName
	}

	updated, err := c.store.UpdateUser(ctx.Context(), storage.UpdateUserInput{
		UserName:    username,
		NewPath:     newPath,
		NewUserName: newUserName,
		NewArn:      iamutil.BuildUserArn(iamutil.DefaultAccountID, finalPath, finalUserName),
	})
	if err != nil {
		debuglogger.Logf("failed to update IAM user %q: %v", finalUserName, err)
		return nil, err
	}

	return &Response{Data: &types.UpdateUserResponse{
		Result: types.UpdateUserResult{User: updated},
	}}, nil
}

func (c IAMApiController) CreateAccessKey(ctx fiber.Ctx) (*Response, error) {
	userName, err := iamutil.GetUserName(ctx, "CreateAccessKey", iamutil.MaxUserLookupLen, iamerr.MissingParameter("UserName"))
	if err != nil {
		return nil, err
	}

	for range 3 {
		accessKeyID, err := iamutil.GenerateAccessKeyID()
		if err != nil {
			return nil, err
		}
		secretAccessKey, err := iamutil.GenerateSecretAccessKey()
		if err != nil {
			return nil, err
		}

		stored, err := c.store.CreateAccessKey(ctx.Context(), storage.CreateAccessKeyInput{
			UserName:        userName,
			AccessKeyID:     accessKeyID,
			SecretAccessKey: secretAccessKey,
			Status:          iamutil.AccessKeyStatusActive,
			CreateDate:      time.Now().UTC().Truncate(time.Second),
		})
		if errors.Is(err, storage.ErrAccessKeyIDAlreadyExists) {
			debuglogger.Logf("IAM access key id collision for user %q: %v", userName, err)
			continue
		}
		if err != nil {
			debuglogger.Logf("failed to create IAM access key for user %q: %v", userName, err)
			return nil, err
		}

		return &Response{
			Data: &types.CreateAccessKeyResponse{
				Result: types.CreateAccessKeyResult{AccessKey: *stored},
			},
		}, nil
	}

	err = fmt.Errorf("generate IAM access key id: exhausted collision retries")
	debuglogger.Logf("failed to create IAM access key for user %q: %v", userName, err)
	return nil, err
}

func (c IAMApiController) UpdateAccessKey(ctx fiber.Ctx) (*Response, error) {
	userName, err := iamutil.GetUserName(ctx, "UpdateAccessKey", iamutil.MaxUserLookupLen, iamerr.MissingParameter("UserName"))
	if err != nil {
		return nil, err
	}

	accessKeyID, ok := iamutil.RequestParam(ctx, "AccessKeyId")
	if !ok || accessKeyID == "" {
		debuglogger.Logf("missing required UpdateAccessKey parameter: AccessKeyId")
		return nil, iamerr.MissingParameter("AccessKeyId")
	}
	if err := iamutil.ValidateAccessKeyID(accessKeyID); err != nil {
		return nil, err
	}

	status, ok := iamutil.RequestParam(ctx, "Status")
	if !ok || status == "" {
		debuglogger.Logf("missing required UpdateAccessKey parameter: Status")
		return nil, iamerr.MissingParameter("Status")
	}
	if err := iamutil.ValidateAccessKeyStatus(status); err != nil {
		return nil, err
	}

	if err := c.store.UpdateAccessKey(ctx.Context(), storage.UpdateAccessKeyInput{
		UserName:    userName,
		AccessKeyID: accessKeyID,
		Status:      status,
	}); err != nil {
		debuglogger.Logf("failed to update IAM access key %q for user %q: %v", accessKeyID, userName, err)
		return nil, err
	}

	return &Response{Data: &types.UpdateAccessKeyResponse{}}, nil
}

func (c IAMApiController) DeleteAccessKey(ctx fiber.Ctx) (*Response, error) {
	userName, err := iamutil.GetUserName(ctx, "DeleteAccessKey", iamutil.MaxUserLookupLen, iamerr.MissingParameter("UserName"))
	if err != nil {
		return nil, err
	}

	accessKeyID, ok := iamutil.RequestParam(ctx, "AccessKeyId")
	if !ok || accessKeyID == "" {
		debuglogger.Logf("missing required DeleteAccessKey parameter: AccessKeyId")
		return nil, iamerr.MissingParameter("AccessKeyId")
	}
	if err := iamutil.ValidateAccessKeyID(accessKeyID); err != nil {
		return nil, err
	}

	if err := c.store.DeleteAccessKey(ctx.Context(), userName, accessKeyID); err != nil {
		debuglogger.Logf("failed to delete IAM access key %q for user %q: %v", accessKeyID, userName, err)
		return nil, err
	}

	return &Response{Data: &types.DeleteAccessKeyResponse{}}, nil
}

func (c IAMApiController) GetAccessKeyLastUsed(ctx fiber.Ctx) (*Response, error) {
	accessKeyID, ok := iamutil.RequestParam(ctx, "AccessKeyId")
	if !ok || accessKeyID == "" {
		debuglogger.Logf("missing required GetAccessKeyLastUsed parameter: AccessKeyId")
		return nil, iamerr.MissingParameter("AccessKeyId")
	}
	if err := iamutil.ValidateAccessKeyID(accessKeyID); err != nil {
		return nil, err
	}

	out, err := c.store.GetAccessKeyLastUsed(ctx.Context(), accessKeyID)
	if err != nil {
		debuglogger.Logf("failed to get IAM access key last used %q: %v", accessKeyID, err)
		return nil, err
	}

	serviceName := out.ServiceName
	if serviceName == "" {
		serviceName = "N/A"
	}
	region := out.Region
	if region == "" {
		region = "N/A"
	}

	var lastUsedDate *time.Time
	if !out.LastUsedDate.IsZero() {
		lastUsedDate = &out.LastUsedDate
	}

	return &Response{Data: &types.GetAccessKeyLastUsedResponse{
		Result: types.GetAccessKeyLastUsedResult{
			UserName: out.UserName,
			AccessKeyLastUsed: types.AccessKeyLastUsed{
				LastUsedDate: lastUsedDate,
				ServiceName:  serviceName,
				Region:       region,
			},
		},
	}}, nil
}

func (c IAMApiController) ListAccessKeys(ctx fiber.Ctx) (*Response, error) {
	userName, err := iamutil.GetUserName(ctx, "ListAccessKeys", iamutil.MaxUserLookupLen, iamerr.MissingParameter("UserName"))
	if err != nil {
		return nil, err
	}

	maxItems, err := iamutil.ParseMaxItems(ctx, "ListAccessKeys")
	if err != nil {
		return nil, err
	}

	marker, _ := iamutil.RequestParam(ctx, "Marker")
	out, err := c.store.ListAccessKeys(ctx.Context(), storage.ListAccessKeysInput{
		UserName: userName,
		Marker:   marker,
		MaxItems: maxItems,
	})
	if err != nil {
		debuglogger.Logf("failed to list IAM access keys for user %q: %v", userName, err)
		return nil, err
	}

	return &Response{Data: &types.ListAccessKeysResponse{
		Result: types.ListAccessKeysResult{
			AccessKeyMetadata: types.AccessKeyMetadataList{Members: out.AccessKeys},
			IsTruncated:       out.IsTruncated,
			Marker:            out.Marker,
		},
	}}, nil
}

func (c IAMApiController) PutUserPolicy(ctx fiber.Ctx) (*Response, error) {
	policyDocument, ok := iamutil.RequestParam(ctx, "PolicyDocument")
	if !ok {
		debuglogger.Logf("missing required PutUserPolicy parameter: PolicyDocument")
		return nil, iamerr.MissingValue("policyDocument")
	}
	if err := policy.Validate("policyDocument", policyDocument); err != nil {
		return nil, err
	}

	policyName, ok := iamutil.RequestParam(ctx, "PolicyName")
	if !ok {
		debuglogger.Logf("missing required PutUserPolicy parameter: PolicyName")
		return nil, iamerr.MissingValue("policyName")
	}
	if err := iamutil.ValidateName("policyName", policyName, iamutil.MaxUserLookupLen); err != nil {
		return nil, err
	}

	userName, err := iamutil.GetUserName(ctx, "PutUserPolicy", iamutil.MaxUserLookupLen, iamerr.MissingValue("userName"))
	if err != nil {
		return nil, err
	}

	// Confirm the user exists before inspecting policy document content
	if _, err := c.store.GetUser(ctx.Context(), userName); err != nil {
		debuglogger.Logf("failed to get IAM user %q for PutUserPolicy: %v", userName, err)
		return nil, err
	}

	if err := policy.Parse(policyDocument); err != nil {
		return nil, err
	}

	if err := c.store.PutUserPolicy(ctx.Context(), storage.PutUserPolicyInput{
		UserName:       userName,
		PolicyName:     policyName,
		PolicyDocument: policyDocument,
	}); err != nil {
		debuglogger.Logf("failed to put IAM user policy %q for user %q: %v", policyName, userName, err)
		return nil, err
	}

	return &Response{Data: &types.PutUserPolicyResponse{}}, nil
}

func (c IAMApiController) GetUserPolicy(ctx fiber.Ctx) (*Response, error) {
	policyName, ok := iamutil.RequestParam(ctx, "PolicyName")
	if !ok {
		debuglogger.Logf("missing required GetUserPolicy parameter: PolicyName")
		return nil, iamerr.MissingValue("policyName")
	}
	if err := iamutil.ValidateName("policyName", policyName, iamutil.MaxUserLookupLen); err != nil {
		return nil, err
	}

	userName, err := iamutil.GetUserName(ctx, "GetUserPolicy", iamutil.MaxUserLookupLen, iamerr.MissingValue("userName"))
	if err != nil {
		return nil, err
	}

	entry, err := c.store.GetUserPolicy(ctx.Context(), userName, policyName)
	if err != nil {
		debuglogger.Logf("failed to get IAM user policy %q for user %q: %v", policyName, userName, err)
		return nil, err
	}

	return &Response{Data: &types.GetUserPolicyResponse{
		Result: types.GetUserPolicyResult{
			UserName:       userName,
			PolicyName:     entry.PolicyName,
			PolicyDocument: iamutil.EncodePolicyDocument(entry.PolicyDocument),
		},
	}}, nil
}

func (c IAMApiController) DeleteUserPolicy(ctx fiber.Ctx) (*Response, error) {
	policyName, ok := iamutil.RequestParam(ctx, "PolicyName")
	if !ok {
		debuglogger.Logf("missing required DeleteUserPolicy parameter: PolicyName")
		return nil, iamerr.MissingValue("policyName")
	}
	if err := iamutil.ValidateName("policyName", policyName, iamutil.MaxUserLookupLen); err != nil {
		return nil, err
	}

	userName, err := iamutil.GetUserName(ctx, "DeleteUserPolicy", iamutil.MaxUserLookupLen, iamerr.MissingValue("userName"))
	if err != nil {
		return nil, err
	}

	if err := c.store.DeleteUserPolicy(ctx.Context(), userName, policyName); err != nil {
		debuglogger.Logf("failed to delete IAM user policy %q for user %q: %v", policyName, userName, err)
		return nil, err
	}

	return &Response{Data: &types.DeleteUserPolicyResponse{}}, nil
}

func (c IAMApiController) ListUserPolicies(ctx fiber.Ctx) (*Response, error) {
	userName, err := iamutil.GetUserName(ctx, "ListUserPolicies", iamutil.MaxUserLookupLen, iamerr.MissingValue("userName"))
	if err != nil {
		return nil, err
	}

	maxItems, err := iamutil.ParseMaxItems(ctx, "ListUserPolicies")
	if err != nil {
		return nil, err
	}

	marker, _ := iamutil.RequestParam(ctx, "Marker")
	out, err := c.store.ListUserPolicies(ctx.Context(), storage.ListUserPoliciesInput{
		UserName: userName,
		Marker:   marker,
		MaxItems: maxItems,
	})
	if err != nil {
		debuglogger.Logf("failed to list IAM user policies for user %q: %v", userName, err)
		return nil, err
	}

	return &Response{Data: &types.ListUserPoliciesResponse{
		Result: types.ListUserPoliciesResult{
			PolicyNames: types.PolicyNameList{Members: out.PolicyNames},
			IsTruncated: out.IsTruncated,
			Marker:      out.Marker,
		},
	}}, nil
}