/*
 * Copyright 2023 Fluence Labs Limited
 *
 * 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 { CLIENT } from '../constants.js';
import { FunctionCallDef, ServiceDef } from '@fluencelabs/interfaces';
import { genTypeName, typeToTs } from '../common.js';
import { capitalize, getFuncArgs } from '../utils.js';

export interface TypeGenerator {
    type(field: string, type: string): string;
    generic(field: string, type: string): string;
    bang(field: string): string;
    funcType(funcDef: AquaFunction): string;
    serviceType(srvName: string, srvDef: ServiceDef): string;
}

export class TSTypeGenerator implements TypeGenerator {
    bang(field: string): string {
        return `${field}!`;
    }

    generic(field: string, type: string): string {
        return `${field}<${type}>`;
    }

    type(field: string, type: string): string {
        return `${field}: ${type}`;
    }

    funcType({ funcDef }: AquaFunction): string {
        const args = getFuncArgs(funcDef.arrow.domain).map(([name, type]) => {
            const [typeDesc, t] = genTypeName(type, capitalize(funcDef.functionName) + 'Arg' + capitalize(name));
            return [typeDesc, `${name}: ${t}`] as const;
        });
        args.push([undefined, `config?: {ttl?: number}`]);

        const argsDefs = args.map(([, def]) => "    " + def);
        const argsDesc = args.filter(([desc]) => desc !== undefined).map(([desc]) => desc);

        const functionOverloads = [
            argsDefs.join(',\n'),
            [`    peer: ${CLIENT}`, ...argsDefs].join(',\n')
        ];
        
        const [resTypeDesc, resType] = genTypeName(funcDef.arrow.codomain, capitalize(funcDef.functionName) + "Result");

        return [
            argsDesc.join('\n'),
            resTypeDesc || "",
            functionOverloads.flatMap(fo => [
                `export function ${funcDef.functionName}(`,
                fo,
                `): Promise<${resType}>;`,
                ''
            ]).join('\n')
        ].filter(s => s !== '').join('\n\n');
    }

    serviceType(srvName: string, srvDef: ServiceDef): string {
        const members = srvDef.functions.tag === 'nil' ? [] : Object.entries(srvDef.functions.fields);

        const interfaceDefs = members
            .map(([name, arrow]) => {
                return `    ${name}: ${typeToTs(arrow)};`;
            })
            .join('\n');

        const interfaces = [`export interface ${srvName}Def {`, interfaceDefs, '}'].join('\n');
        
        const peerDecl = `peer: ${CLIENT}`;
        const serviceDecl = `service: ${srvName}Def`;
        const serviceIdDecl = `serviceId: string`;
        const registerServiceArgs = [
            [serviceDecl],
            [serviceIdDecl, serviceDecl],
            [peerDecl, serviceDecl],
            [peerDecl, serviceIdDecl, serviceDecl]
        ];

        return [interfaces, ...registerServiceArgs.map(registerServiceArg => {
            const args = registerServiceArg.join(', ');
            return `export function register${srvName}(${args}): void;`
        })].join('\n');
    }
}

export class JSTypeGenerator implements TypeGenerator {
    bang(field: string): string {
        return field;
    }

    generic(field: string, type: string): string {
        return field;
    }

    type(field: string, type: string): string {
        return field;
    }

    funcType(): string {
        return '';
    }

    serviceType(): string {
        return '';
    }
}

export interface AquaFunction {
    funcDef: FunctionCallDef;
    script: string;
}

export interface CompilationResult {
    services: Record<string, ServiceDef>;
    functions: Record<string, AquaFunction>;
}

export interface EntityGenerator {
    generate(compilationResult: CompilationResult): string;
}

export type OutputType = 'js' | 'ts';