/**
# Copyright (c) NVIDIA CORPORATION.  All rights reserved.
#
# 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 image

import (
	"fmt"
	"strings"

	"github.com/opencontainers/runtime-spec/specs-go"
)

type builder struct {
	spec           *specs.Spec
	env            map[string]string
	mounts         []specs.Mount
	disableRequire bool

	swarmResourceEnvvars []string
}

// New creates a new CUDA image from the input options.
func New(opt ...Option) (CUDA, error) {
	b := &builder{}
	for _, o := range opt {
		if err := o(b); err != nil {
			return CUDA{}, err
		}
	}
	if b.env == nil {
		b.env = make(map[string]string)
	}

	return b.build()
}

// build creates a CUDA image from the builder.
func (b builder) build() (CUDA, error) {
	if b.disableRequire {
		b.env[EnvVarNvidiaDisableRequire] = "true"
	}

	c := CUDA{
		env:                  b.env,
		mounts:               b.mounts,
		spec:                 b.spec,
		swarmResourceEnvvars: b.swarmResourceEnvvars,
	}
	return c, nil
}

// Option is a functional option for creating a CUDA image.
type Option func(*builder) error

// WithDisableRequire sets the disable require option.
func WithDisableRequire(disableRequire bool) Option {
	return func(b *builder) error {
		b.disableRequire = disableRequire
		return nil
	}
}

// WithEnv sets the environment variables to use when creating the CUDA image.
// Note that this also overwrites the values set with WithEnvMap.
func WithEnv(env []string) Option {
	return func(b *builder) error {
		envmap := make(map[string]string)
		for _, e := range env {
			parts := strings.SplitN(e, "=", 2)
			if len(parts) != 2 {
				return fmt.Errorf("invalid environment variable: %v", e)
			}
			envmap[parts[0]] = parts[1]
		}
		return WithEnvMap(envmap)(b)
	}
}

// WithEnvMap sets the environment variable map to use when creating the CUDA image.
// Note that this also overwrites the values set with WithEnv.
func WithEnvMap(env map[string]string) Option {
	return func(b *builder) error {
		b.env = env
		return nil
	}
}

// WithMounts sets the mounts associated with the CUDA image.
func WithMounts(mounts []specs.Mount) Option {
	return func(b *builder) error {
		b.mounts = mounts
		return nil
	}
}

// WithSpec sets the OCI spec to use when creating the CUDA image.
func WithSpec(s *specs.Spec) Option {
	return func(b *builder) error {
		b.spec = s
		return nil
	}
}

// WithSwarmResource sets the swarm resource for the CUDA image.
func WithSwarmResource(resource ...string) Option {
	return func(b *builder) error {
		if len(resource) == 0 {
			return fmt.Errorf("swarm resource cannot be empty")
		}
		b.swarmResourceEnvvars = []string{}
		// if resource is a single string, split it by comma
		if len(resource) == 1 && strings.Contains(resource[0], ",") {
			candidates := strings.Split(resource[0], ",")
			for _, c := range candidates {
				trimmed := strings.TrimSpace(c)
				if len(trimmed) > 0 {
					b.swarmResourceEnvvars = append(b.swarmResourceEnvvars, trimmed)
				}
			}
			return nil
		}

		b.swarmResourceEnvvars = append(b.swarmResourceEnvvars, resource...)
		return nil
	}
}

// WithPrivileged sets the privileged option for the CUDA image.
// This is to allow testing the privileged mode of the container.
// DO NOT USE THIS IN PRODUCTION CODE. FOR TESTING PURPOSES ONLY.
func WithPrivileged(privileged bool) Option {
	return func(b *builder) error {
		b.spec = &specs.Spec{
			Process: &specs.Process{
				Capabilities: &specs.LinuxCapabilities{
					Bounding: []string{"CAP_SYS_FOO"},
				},
			},
		}
		if privileged {
			if b.spec.Process.Capabilities == nil {
				b.spec.Process.Capabilities = &specs.LinuxCapabilities{}
			}
			b.spec.Process.Capabilities.Bounding = append(b.spec.Process.Capabilities.Bounding, "CAP_SYS_ADMIN")
		}
		return nil
	}
}