const { Injectable } = require('flitter-di')

class ServiceConfig extends Injectable {
    static get services() {
        return [...super.services, 'utility']
    }

    _data = {
        after: ['syslog.target', 'network.target'],
        type: 'simple',
        restart: 'always',
        restart_after: '2s',
        install_to: 'multi-user.target',
    }

    constructor(merge_data = {}) {
        super()
        this._data = {...this._data, ...merge_data}
    }

    name(set) { return this._get_or_set('name', set) }

    description(set) { return this._get_or_set('description', set) }

    after(set) { return this._get_or_set('after', set, true) }

    restart(set) { return this._get_or_set('restart', set) }

    restart_after(set) { return this._get_or_set('restart_after', set) }

    type(set) { return this._get_or_set('type', set) }

    user(set) { return this._get_or_set('user', set) }

    group(set) { return this._get_or_set('group', set) }

    directory(set) { return this._get_or_set('directory', set) }

    execute(set) { return this._get_or_set('execute', set) }

    env(set) { return this._get_or_set('env', set) }

    install_to(set) { return this._get_or_set('install_to', set) }

    _export() {
        return this.utility.deep_copy(this._data)
    }

    _build() {
        this._validate()
        const lines = []
        lines.push('[Unit]')
        if ( this.description() ) lines.push(`Description=${this.description()}`)
        if ( this.after() ) {
            for ( const item of this.after() ) {
                lines.push(`After=${item}`)
            }
        }
        lines.push('\n[Service]')
        if ( this.restart() ) {
            lines.push(`Restart=${this.restart()}`)

            if ( this.restart_after() ) {
                lines.push(`RestartSec=${this.restart_after()}`)
            }
        }

        if ( this.user() ) {
            lines.push(`User=${this.user()}`)
        }

        if ( this.group() ) {
            lines.push(`Group=${this.group()}`)
        }

        if ( this.directory() ) {
            lines.push(`WorkingDirectory=${this.directory()}`)
        }

        if ( this.execute() ) {
            lines.push(`ExecStart=${this.execute()}`)
        }

        if ( this.env() ) {
            lines.push(`Environment=${this.env()}`)
        }

        if ( this.install_to() ) {
            lines.push('\n[Install]')
            lines.push(`WantedBy=${this.install_to()}`)
        }

        return lines.join('\n')
    }

    _validate() {
        const required_fields = ['name', 'description', 'after', 'type', 'user', 'group', 'directory', 'execute']
        for ( const field of required_fields ) {
            if ( !this[field]() ) throw new Error(`Missing required service config field: ${field}`)
        }
    }
    
    _get_or_set(field, value, arr = false) {
        if ( value ) {
            if ( arr ) {
                if ( !this._data[field] ) this._data[field] = []
                this._data[field].push(value)
            } else this._data[field] = value
            return this
        }
        
        return this._data[field]
    }
}

module.exports = exports = ServiceConfig