const { Controller } = require('libflitter')

class IAMController extends Controller {
    static get services() {
        return [...super.services, 'models']
    }

    async check_entity_access(req, res, next) {
        const Policy = this.models.get('iam:Policy')

        if ( !req.body.entity_id && !req.body.target_id )
            return res.status(400)
                .message('Missing one or more required fields: entity_id, target_id')
                .api()

        return res.api(await Policy.check_entity_access(req.body.entity_id, req.body.target_id))
    }

    async check_user_access(req, res, next) {
        const User = this.models.get('auth:User')
        const Policy = this.models.get('iam:Policy')

        if ( !req.body.target_id )
            return res.status(400)
                .message('Missing required field: target_id')
                .api()

        let user = req.user
        if ( req.body.user_id && req.body.user_id !== 'me' )
            user = await User.findById(req.body.user_id)

        if ( !user )
            return res.status(404)
                .message('User not found with that ID.')
                .api()

        if ( !req.user.can(`auth:user:${user.id}:view`) )
            return res.status(401)
                .message('Insufficient permissions.')
                .api()

        return res.api(await Policy.check_user_access(user, req.body.target_id))
    }

    async get_policies(req, res, next) {
        const Policy = this.models.get('iam:Policy')
        const policies = await Policy.find({ active: true })
        const data = []

        for ( const policy of policies ) {
            if ( req.user.can(`iam:policy:${policy.id}:view`) ) {
                data.push(await policy.to_api())
            }
        }

        return res.api(data)
    }

    async get_policy(req, res, next) {
        const Policy = this.models.get('iam:Policy')
        const policy = await Policy.findById(req.params.id)

        if ( !policy )
            return res.status(404)
                .message('Policy not found with that ID.')
                .api()

        if ( !req.user.can(`iam:policy:${policy.id}:view`) )
            return res.status(401)
                .message('Insufficient permissions.')
                .api()

        return res.api(await policy.to_api())
    }

    async create_policy(req, res, next) {
        const Policy = this.models.get('iam:Policy')

        const required_fields = ['entity_type', 'entity_id', 'access_type', 'target_type', 'target_id']
        for ( const field of required_fields ) {
            if ( !req.body[field] )
                return res.status(400)
                    .message(`Missing required field: ${field}`)
                    .api()
        }

        if ( !['user', 'group'].includes(req.body.entity_type) )
            return res.status(400)
                .message('Invalid entity_type. Must be one of: user, group.')
                .api()

        // Make sure the entity_id is valid
        if ( req.body.entity_type === 'user' ) {
            const User = this.models.get('auth:User')
            const user = await User.findById(req.body.entity_id)
            if ( !user || !req.user.can(`auth:user:${user.id}:view`) )
                return res.status(400)
                    .message('Invalid entity_id.')
                    .api()
        } else if ( req.body.entity_type === 'group' ) {
            const Group = this.models.get('auth:Group')
            const group = await Group.findById(req.body.entity_id)
            if ( !group || !group.active || !req.user.can(`auth:group:${group.id}:view`) )
                return res.status(400)
                    .message('Invalid entity_id.')
                    .api()
        }

        if ( !['allow', 'deny'].includes(req.body.access_type) )
            return res.status(400)
                .message('Invalid access_type. Must be one of: allow, deny.')
                .api()

        if ( !['application'].includes(req.body.target_type) )
            return res.status(400)
                .message('Invalid target_type. Must be one of: application.')
                .api()

        // Make sure the target_id is valid
        if ( req.body.target_type === 'application' ) {
            const Application = this.models.get('Application')
            const app = await Application.findById(req.body.target_id)
            if ( !app || !app.active || !req.user.can(`app:${app.id}:view`) )
                return res.status(400)
                    .message('Invalid target_id.')
                    .api()
        }

        const policy = new Policy({
            entity_type: req.body.entity_type,
            entity_id: req.body.entity_id,
            access_type: req.body.access_type,
            target_type: req.body.target_type,
            target_id: req.body.target_id,
        })

        await policy.save()
        req.user.allow(`iam:policy:${policy.id}`)
        await req.user.save()
        return res.api(await policy.to_api())
    }

    async update_policy(req, res, next) {
        const Policy = this.models.get('iam:Policy')
        const policy = await Policy.findById(req.params.id)

        if ( !policy || !policy.active )
            return res.status(404)
                .message('Policy not found with that ID.')
                .api()

        if ( !req.user.can(`iam:policy:${policy.id}:update`) )
            return res.status(401)
                .message('Insufficient permissions.')
                .api()

        const required_fields = ['entity_type', 'entity_id', 'access_type', 'target_type', 'target_id']
        for ( const field of required_fields ) {
            if ( !req.body[field] )
                return res.status(400)
                    .message(`Missing required field: ${field}`)
                    .api()
        }

        if ( !['user', 'group'].includes(req.body.entity_type) )
            return res.status(400)
                .message('Invalid entity_type. Must be one of: user, group.')
                .api()

        // Make sure the entity_id is valid
        if ( req.body.entity_type === 'user' ) {
            const User = this.models.get('auth:User')
            const user = await User.findById(req.body.entity_id)
            if ( !user || !req.user.can(`auth:user:${user.id}:view`) )
                return res.status(400)
                    .message('Invalid entity_id.')
                    .api()
        } else if ( req.body.entity_type === 'group' ) {
            const Group = this.models.get('auth:Group')
            const group = await Group.findById(req.body.entity_id)
            if ( !group || !group.active || !req.user.can(`auth:group:${group.id}:view`) )
                return res.status(400)
                    .message('Invalid entity_id.')
                    .api()
        }

        if ( !['allow', 'deny'].includes(req.body.access_type) )
            return res.status(400)
                .message('Invalid access_type. Must be one of: allow, deny.')
                .api()

        if ( !['application'].includes(req.body.target_type) )
            return res.status(400)
                .message('Invalid target_type. Must be one of: application.')
                .api()

        // Make sure the target_id is valid
        if ( req.body.target_type === 'application' ) {
            const Application = this.models.get('Application')
            const app = await Application.findById(req.body.target_id)
            if ( !app || !app.active || !req.user.can(`app:${app.id}:view`) )
                return res.status(400)
                    .message('Invalid target_id.')
                    .api()
        }

        policy.entity_type = req.body.entity_type
        policy.entity_id = req.body.entity_id
        policy.access_type = req.body.access_type
        policy.target_type = req.body.target_type
        policy.target_id = req.body.target_id
        await policy.save()
        return res.api()
    }

    async delete_policy(req, res, next) {
        const Policy = this.models.get('iam:Policy')
        const policy = await Policy.findById(req.params.id)

        if ( !policy || !policy.active )
            return res.status(404)
                .message('Policy not found with that ID.')
                .api()

        if ( !req.user.can(`iam:policy:${policy.id}:delete`) )
            return res.status(401)
                .message('Insufficient permissions.')
                .api()

        policy.active = false
        await policy.save()
        return res.api()
    }
}

module.exports = exports = IAMController