/*
 * Copyright © 2020 Atomist, Inc.
 *
 * 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.
 */

import { AutomationContextAware, HandlerContext } from "@atomist/automation-client/lib/HandlerContext";
import { Arg, CommandIncoming } from "@atomist/automation-client/lib/internal/transport/RequestProcessor";
import { HandlerResponse } from "@atomist/automation-client/lib/internal/transport/websocket/WebSocketMessageClient";
import { Parameter } from "@atomist/automation-client/lib/metadata/automationMetadata";
import * as _ from "lodash";
import { CommandListenerExecutionInterruptError } from "../../api-helper/machine/handlerRegistrations";
import { ParameterStyle } from "../registration/CommandRegistration";
import { ParametersObjectValue } from "../registration/ParametersDefinition";

/**
 * Object with properties defining parameters. Useful for combination via spreads.
 */
export type ParametersPromptObject<PARAMS, K extends keyof PARAMS = keyof PARAMS> = Record<K, ParametersObjectValue & { force?: boolean }>;

/**
 * Factory to create a ParameterPrompt
 */
export type ParameterPromptFactory<PARAMS> = (ctx: HandlerContext) => ParameterPrompt<PARAMS>;

/**
 * Options to configure the parameter prompt
 */
export interface ParameterPromptOptions {
    /** Optional thread identifier to send this message to or true to send
     * this to the message that triggered this command.
     */
    thread?: boolean | string;

    /**
     * Configure strategy on how to ask for parameters in chat or web
     */
    parameterStyle?: ParameterStyle;

    /**
     * Configure auto submit strategy for when all required parameters are collected
     */
    autoSubmit?: boolean;
}

/**
 * ParameterPrompts let the caller prompt for the provided parameters
 */
export type ParameterPrompt<PARAMS> = (
    parameters: ParametersPromptObject<PARAMS>,
    options?: ParameterPromptOptions,
) => Promise<PARAMS>;

/* tslint:disable:cyclomatic-complexity */
/**
 * No-op NoParameterPrompt implementation that never prompts for new parameters
 * @constructor
 */
export const NoParameterPrompt: ParameterPrompt<any> = async () => ({});

export const AtomistContinuationMimeType = "application/x-atomist-continuation+json";

/* tslint:disable:cyclomatic-complexity */
/**
 * Default ParameterPromptFactory that uses the WebSocket connection to send parameter prompts to the backend.
 * @param ctx
 */
export function commandRequestParameterPromptFactory<T>(ctx: HandlerContext): ParameterPrompt<T> {
    return async (parameters, options = {}) => {
        const trigger = ((ctx as any) as AutomationContextAware).trigger as CommandIncoming;

        const existingParameters = trigger.parameters;
        const newParameters = _.cloneDeep(parameters);

        // Find out if - and if - which parameters are actually missing
        let requiredMissing = false;
        const params: any = {};
        for (const parameter in parameters) {
            if (parameters.hasOwnProperty(parameter)) {
                const existingParameter = existingParameters.find(p => p.name === parameter);
                if (!existingParameter) {
                    // If required isn't defined it means the parameter is required
                    if (newParameters[parameter].required || newParameters[parameter].required === undefined) {
                        requiredMissing = true;
                    }
                } else {
                    // Do some validation against the rules
                    const parameterDefinition = newParameters[parameter];
                    const value = existingParameter.value;

                    // Force question
                    if (parameterDefinition.force) {
                        trigger.parameters = trigger.parameters.filter(p => p.name !== parameter);
                        requiredMissing = true;
                        continue;
                    }
                    // Verify pattern
                    if (parameterDefinition.pattern && !!value && !value.match(parameterDefinition.pattern)) {
                        requiredMissing = true;
                        continue;
                    }
                    // Verify minLength
                    const minLength = parameterDefinition.minLength || (parameterDefinition as any).min_length;
                    if (minLength !== undefined && !!value && value.length < minLength) {
                        requiredMissing = true;
                        continue;
                    }
                    // Verify maxLength
                    const maxLength = parameterDefinition.maxLength || (parameterDefinition as any).max_length;
                    if (maxLength !== undefined && !!value && value.length > maxLength) {
                        requiredMissing = true;
                        continue;
                    }

                    params[parameter] = existingParameter.value;
                    delete newParameters[parameter];
                }
            }
        }

        // If no parameters are missing we can return the already collected parameters
        if (!requiredMissing) {
            return params;
        }

        // Set up the thread_ts for this response message
        let threadTs: string;
        if (options.thread === true && !!trigger.source) {
            threadTs = _.get(trigger.source, "slack.message.ts");
        } else if (typeof options.thread === "string") {
            threadTs = options.thread;
        }

        const destination = _.cloneDeep(trigger.source);
        _.set(destination, "slack.thread_ts", threadTs);

        // Create a continuation message using the existing HandlerResponse and mixing in parameters
        // and parameter_specs
        const response: HandlerResponse & {
            parameters: Arg[];
            parameter_specs: Parameter[];
            question: any;
            auto_submit: boolean;
        } = {
            api_version: "1",
            correlation_id: trigger.correlation_id,
            team: trigger.team,
            command: trigger.command,
            source: trigger.source,
            destinations: [destination],
            parameters: [...(trigger.parameters || []), ...(trigger.mapped_parameters || [])],
            auto_submit: !!options.autoSubmit ? options.autoSubmit : undefined,
            question: !!options.parameterStyle ? options.parameterStyle.toString() : undefined,
            parameter_specs: _.map(newParameters, (v, k) => ({
                name: k,
                description: v.description,
                required: v.required !== undefined ? v.required : true,
                pattern: v.pattern ? v.pattern.source : undefined,
                valid_input: v.validInput,
                max_length: v.maxLength,
                min_length: v.minLength,
                display_name: v.displayName,
                default_value: v.defaultValue,
                type: v.type,
            })),
            content_type: AtomistContinuationMimeType,
        };

        await ctx.messageClient.respond(response);
        throw new CommandListenerExecutionInterruptError(
            `Prompting for new parameters: ${_.map(newParameters, (v, k) => k).join(", ")}`,
        );
    };
}
/* tslint:enable:cyclomatic-complexity */