import * as color from 'colors/safe'
import {Logging} from "../service/Logging";
import {Inject} from "../di";
import {ErrorWithContext} from "../util";

/**
 * Class with logic for handling errors that are thrown at the run-level of the application.
 *
 * Colloquially, these are errors thrown ourside the request-lifecycle that are not caught by a unit.
 */
export class RunLevelErrorHandler {
    @Inject()
    protected logging!: Logging

    /**
     * Get the error handler function.
     * @type (e: Error) => void
     */
    get handle(): (e: Error) => void {
        return (e: Error) => {
            this.display(e)
            process.exit(1)
        }
    }

    /**
     * Wrap the given base Error instance into an ErrorWithContext.
     * @param e
     * @param context
     */
    wrapContext(e: Error, context: {[key: string]: any}): ErrorWithContext {
        if ( e instanceof ErrorWithContext ) {
            e.context = {...e.context, ...context}
            return e
        }

        const error = new ErrorWithContext(e.message)
        error.originalError = e
        error.context = context
        error.stack = e.stack
        return error
    }

    /**
     * Log the error to the logger.
     * @param {Error} e
     */
    display(e: Error) {
        let operativeError = e
        let context: {[key: string]: string} = {}
        if ( e instanceof ErrorWithContext ) {
            if ( e.originalError ) operativeError = e.originalError
            context = e.context
        }

        const contextDisplay = Object.keys(context).map(key => ` - ${key}: ${context[key]}`).join('\n')

        try {
            let errorString = `RunLevelErrorHandler invoked:

${color.bgRed('                                ')}
${color.bgRed('    UNCAUGHT RUN-LEVEL ERROR    ')}
${color.bgRed('                                ')}

${operativeError.constructor ? operativeError.constructor.name : operativeError.name}
${color.red(`---------------------------------------------------`)}
${operativeError.stack}
`

            if ( contextDisplay ) {
                errorString += `
With the following context:
${contextDisplay}
`
            }
            
            this.logging.error(errorString, true)
        } catch (display_e) {
            // The error display encountered an error...
            // just throw the original so it makes it out
            console.error('RunLevelErrorHandler encountered an error:', display_e.message)
            throw operativeError
        }
    }
}