const PackageManager = require('./PackageManager')

class APTManager extends PackageManager {
    _command_install_package = 'apt-get install -y %%PACKAGE%%'
    _command_uninstall_package = 'apt-get purge -y %%PACKAGE%%'
    _command_update_package = 'apt-get upgrade -y %%PACKAGE%%'
    _command_reinstall_package = 'apt-get install -y --reinstall %%PACKAGE%%'
    _command_clear_cache = 'apt-get clean'
    _command_count_installed = 'dpkg --list | wc -l'
    _command_count_available = 'apt-cache pkgnames | wc -l'
    _command_add_repo = `add-apt-repository '%%URI%%`
    _command_preflight = 'apt-get update'

    _status_keymap = {
        package: 'name',
        filename: 'source',
        section: 'repository',
        'description-en': 'summary',
    }

    async status(pkg) {
        await this.preflight()
        const result = await this._host.execute(`apt-cache show ${pkg}`)
        if ( ![0, 100].includes(result.exit_code) ) {
            throw new Error('Unable to determine package information: '+result.stderr.join('\n'))
        }

        if ( result.exit_code === 100 ) {
            return {
                name: pkg,
                state: this.constructor.PACKAGE_STATE_UNKNOWN,
            }
        }

        const data = {}
        let last_data_key = false
        for ( const line of result.clean_out ) {
            if ( last_data_key && line.startsWith(' ') ) {
                data[last_data_key] += line
            } else {
                const parts = line.trim().split(':')
                const key = parts[0].toLowerCase()
                const value = parts.slice(1).join(':').trim()
                data[key] = value
                last_data_key = key
            }
        }

        for ( const key in this._status_keymap ) {
            if ( !this._status_keymap.hasOwnProperty(key) ) continue
            if ( data[key] ) {
                data[this._status_keymap[key]] = data[key]
                delete data[key]
            }
        }

        // check installation state
        const install_result = await this._host.execute(`dpkg -s ${pkg}`)
        data.state = install_result.exit_code === 0 ? this.constructor.PACKAGE_STATE_INSTALLED : this.constructor.PACKAGE_STATE_AVAILABLE

        return data
    }

    async list_updates() {
        await this.preflight()
        const result = await this._host.execute(`apt-get --just-print upgrade`)
        if ( result.exit_code !== 0 ) {
            throw new Error('Unable to determine packages for update: '+result.stderr.join('\n'))
        }

        let start_index = -1
        let end_index = -1
        for ( let i in result.clean_out ) {
            const line = result.clean_out[i]
            if ( line.toLowerCase().indexOf('packages will be upgraded') > -1 ) {
                start_index = Number(i)+1
            } else if ( start_index > -1 && i >= start_index ) {
                if ( line.indexOf('newly installed,') > -1 ) break
                else {
                    end_index = Number(i)
                }
            }
        }

        const package_strings = result.clean_out.slice(start_index, end_index+1).join(' ').split(' ').filter(Boolean).map(x => x.trim())
        const updates = result.clean_out.filter(x => x.startsWith('Inst ')).map(x => {
            x = x.substring(5)
            x = x.split(' ')
            const data = {
                name: x[0],
                version: x[1].slice(1, -1),
                repository: x[3].replace(/,/g, ''),
                architecture: x.reverse()[0].replace(/[\[\])(]/g, '')
            }
            return data
        }).filter(x => package_strings.includes(x.name))
        return updates
    }

    async list_repos() {
        await this.preflight()
        const result = await this._host.execute(`apt-cache policy`)
        if ( result.exit_code !== 0 ) {
            throw new Error('Unable to read repository list: '+result.stderr.join('\n'))
        }

        const lines = []
        for ( const line of result.clean_out ) {
            if ( line.trim().startsWith('500') ) {
                lines.push(line)
            } else if ( line.toLowerCase().startsWith('pinned packages') ) {
                break
            }
        }

        return lines.map(x => x.trim()).filter(x => x.startsWith('500')).map(x => x.split(' ')[2])
    }

    async list_installed() {
        const result = await this._host.execute(`dpkg --list`)
        if ( result.exit_code !== 0 ) {
            throw new Error('Unable to determine installed packages: '+result.stderr.join('\n'))
        }

        let header_line = result.clean_out.filter(x => x.trim().startsWith('+'))[0]
        let drop_count = 0
        while ( header_line.startsWith('+') ) {
            drop_count += 1
            header_line = header_line.substring(1)
        }

        let start_at = 0
        for ( let i in result.clean_out ) {
            if ( result.clean_out[i].startsWith('+') ) {
                start_at = Number(i)+1
                break
            }
        }

        return result.clean_out.slice(start_at).map(x => {
            x = x.substring(drop_count).trim().split(' ').filter(Boolean)
            return {
                name: x[0],
                version: x[1],
                architecture: x[2],
                summary: x.slice(3).join(' ')
            }
        })
    }

    async search(pkg) {
        await this.preflight()
        const result = await this._host.execute(`apt-cache search ${pkg}`)
        if ( result.exit_code !== 0 ) {
            throw new Error('Unable to search the package cache: '+result.stderr.join('\n'))
        }

        const results = []
        for ( const line of result.clean_out ) {
            const parts = line.trim().split(' - ').map(x => x.trim())
            results.push({
                name: parts[0],
                summary: parts[1]
            })
        }
        return results
    }

    async preflight() {
        const result = await this._host.execute(this._command_preflight)
        if ( result.exit_code !== 0 ) {
            throw new Error('Error encountered during preflight for APTManager: '+result.stderr.join('\n'))
        }
    }
}

module.exports = exports = APTManager