/* eslint-disable no-useless-escape */
class Resolver {

    constructor(client) {
        this.client = client;
    }

    components(str = '', type, exact = true) {

        const string = str.toLowerCase();

        const components = this.client.registry.components
            .filter((c) => c.type === type)
            .filter(exact ? filterExact(string) : filterInexact(string)) //eslint-disable-line no-use-before-define
            .array();

        return components || [];

    }

    resolveBoolean(input) {
        input = input.toLowerCase();
        const truthy = [ 'on', 'true', 'yes', 'enable', 'y' ];
        const falsey = [ 'off', 'false', 'no', 'disable', 'n' ];

        if(truthy.includes(input)) {
            return true;
        } else if (falsey.includes(input)) {
            return false;
        } 
        return null;
        
    } 

    /**
     * Resolves methods used primarily for settings, also deals with appending the arguments into existing lists
     *
     * @param {Array<String>} args The incoming arguments with the first element being the method ex. ['add','ban','kick']
     * @param {Array<String>} valid An array of items to compare to, if an argument doesn't exist in this array it'll be skipped over
     * @param {Array<String>} [existing=[]] Existing values in the array, valid elements will be appended to this
     * @returns {Object}
     * @memberof Resolver
     */
    resolveMethod(args, valid, existing = []) {

        const methods = {
            list: ['view', 'list', '?'],
            add: ['add', '+'],
            remove: ['remove', 'delete', '-']
        };

        if (!args.length) return false;
        // eslint-disable-next-line prefer-const
        let [method, ...rest] = args;
        method = method.toLowerCase();
        
        if (!rest.length) {
            if (methods.list.includes(method)) return { method: 'list', rest };
            if (methods.add.includes(method)) return { method: 'add', rest };
            if (methods.remove.includes(method)) return { method: 'remove', rest };
        }

        if (methods.list.includes(method)) {
            return { method: 'list' };
        } else if (methods.add.includes(method)) {
            const added = [];
            for (let elem of rest) {
                elem = elem.toLowerCase();
                if (existing.includes(elem) || valid && !valid.includes(elem)) continue;
                added.push(elem);
                existing.push(elem);
            }

            return { rest, method: 'add', changed: added, result: existing };
        } else if (methods.remove.includes(method)) {
            const removed = [];
            for (let elem of rest) {
                elem = elem.toLowerCase();
                if (!existing.includes(elem) || removed.includes(elem) || valid && !valid.includes(elem)) continue;
                removed.push(elem);
                existing.splice(existing.indexOf(elem), 1);
            }

            return { rest, method: 'remove', changed: removed, result: existing };
        }
        
        return false;

    }
    
    async resolveMemberAndUser(string, guild) {

        const str = string.toLowerCase();
        const index = guild ? guild.members.cache : this.client.users.cache;

        let member = null;
        if((/<@!?(\d{17,21})>/iyu).test(str)) { //mentions
            const matches = (/<@!?(\d{17,21})>/iuy).exec(str);
            member = index.get(matches[1]);
            if(!member) {
                try {
                    member = await index.fetch(matches[1]);
                } catch(e) {
                    try {
                        member = await this.client.users.cache.fetch(matches[1]);
                    } catch(e) {} //eslint-disable-line no-empty
                } //eslint-disable-line no-empty
            }
        } else if((/\d{17,21}/iuy).test(str)) { //id
            const matches = (/(\d{17,21})/iuy).exec(str);
            member = index.get(matches[1]);
            if(!member) {
                try {
                    member = await index.fetch(matches[1]);
                } catch(e) {
                    try {
                        member = await this.client.users.cache.fetch(matches[1]);
                    } catch(e) {} //eslint-disable-line no-empty
                } //eslint-disable-line no-empty
            }
        } else if((/(.{2,32})#(\d{4})/iuy).test(str)) { //username#discrim
            const matches = (/(.{2,32})#(\d{4})/iuy).exec(str);
            member = guild
                ? guild.members.cache.filter((m) => m.user.username === matches[1] && m.user.discriminator === matches[2]).first()
                : this.client.users.cache.filter((u) => u.username === matches[1] && u.discriminator === matches[2]).first();
        }

        return member || null;

    }

    /**
     * Resolve several user resolveables
     *
     * @param {array<string>} [resolveables=[]] an array of user resolveables (name, id, tag)
     * @param {boolean} [strict=false] whether or not to attempt resolving by partial usernames
     * @returns {array || boolean} Array of resolved users or false if none were resolved
     * @memberof Resolver
     */
    async resolveUsers(resolveables = [], strict = false) {

        if(typeof resolveables === 'string') resolveables = [ resolveables ];
        if(resolveables.length === 0) return false;
        const { users } = this.client;
        const resolved = [];
        
        for(const resolveable of resolveables) {

            if((/<@!?([0-9]{17,21})>/u).test(resolveable)) {

                const [, id] = resolveable.match(/<@!?([0-9]{17,21})>/u);
                const user = await users.fetch(id).catch((err) => {
                    if(err.code === 10013) return false; 
                    this.client.logger.warn(err); return false; 
 
                });
                if(user) resolved.push(user);

            } else if((/(id:)?([0-9]{17,21})/u).test(resolveable)) {

                const [,, id] = resolveable.match(/(id:)?([0-9]{17,21})/u);
                const user = await users.fetch(id).catch((err) => {
                    if(err.code === 10013) return false; 
                    this.client.logger.warn(err); return false; 
 
                });
                if(user) resolved.push(user);

            } else if((/^@?([\S\s]{1,32})#([0-9]{4})/u).test(resolveable)) {

                const m = resolveable.match(/^@?([\S\s]{1,32})#([0-9]{4})/u);
                const username = m[1].toLowerCase();
                const discrim = m[2].toLowerCase();
                const user = users.cache.filter((u) => u.username.toLowerCase() === username && u.discriminator === discrim).first();
                if(user) resolved.push(user);

            } else if(!strict) {

                const name = resolveable.toLowerCase();
                const user = users.cache.filter((u) => u.username.toLowerCase().includes(name)).first();
                if(user) resolved.push(user);

            }

        }

        return resolved.length ? resolved : false;

    }

    async resolveUser(resolveable, strict) {

        if (!resolveable) return false;
        const result = await this.resolveUsers([ resolveable ], strict);
        return result ? result[0] : false;
        
    }

    /**
     * Resolve multiple member resolveables
     *
     * @param {array<string>} [resolveables=[]] an array of member resolveables (name, nickname, tag, id)
     * @param {boolean} [strict=false] whether or not to attempt resolving by partial matches
     * @param {Guild} guild the guild in which to look for members
     * @returns {array<GuildMember> || boolean} an array of resolved members or false if none were resolved
     * @memberof Resolver
     */
    async resolveMembers(resolveables = [], guild, strict = false) {

        if(typeof resolveables === 'string') resolveables = [ resolveables ];
        if(resolveables.length === 0) return false;
        const { members } = guild;
        const resolved = [];

        for(const resolveable of resolveables) {

            if((/<@!?([0-9]{17,21})>/u).test(resolveable)) {

                const [, id] = resolveable.match(/<@!?([0-9]{17,21})>/u);
                const member = await members.fetch(id).catch((err) => {
                    if(err.code === 10007) return false; 
                    this.client.logger.warn(err); return false; 
 
                });
                if(member) resolved.push(member);

            } else if((/(id:)?([0-9]{17,21})/u).test(resolveable)) {

                const [,, id] = resolveable.match(/(id:)?([0-9]{17,21})/u);
                const member = await members.fetch(id).catch((err) => {
                    if(err.code === 10007) return false; 
                    this.client.logger.warn(err); return false; 
 
                });
                if(member) resolved.push(member);

            } else if((/^@?([\S\s]{1,32})#([0-9]{4})/u).test(resolveable)) {

                const m = resolveable.match(/^@?([\S\s]{1,32})#([0-9]{4})/u);
                const username = m[1].toLowerCase();
                const discrim = m[2].toLowerCase();
                const member = members.cache.filter((m) => m.user.username.toLowerCase() === username && m.user.discriminator === discrim).first();
                if(member) resolved.push(member);

            } else if((/^@?([\S\s]{1,32})/u).test(resolveable) && guild && !strict) {

                const nickname = resolveable.match(/^@?([\S\s]{1,32})/u)[0].toLowerCase();
                const member = members.cache.filter((m) => m && m.user && 
                        ((!m.nickname ? false : m.nickname.toLowerCase() === nickname) || 
                        (!m.nickname ? false : m.nickname.toLowerCase().includes(nickname)) || 
                        m.user.username.toLowerCase().includes(nickname) || 
                        m.user.username.toLowerCase() === nickname)).first();
                if(member) resolved.push(member);
          
            }

        }

        return resolved.length > 0 ? resolved : false;

    }

    async resolveMember(resolveable, guild, strict) {

        if (!resolveable) return false;
        const result = await this.resolveMembers([ resolveable ], guild, strict);
        return result ? result[0] : false;

    }

    /**
     * Resolve multiple channels
     *
     * @param {array<string>} [resolveables=[]] an array of channel resolveables (name, id)
     * @param {guild} guild the guild in which to look for channels
     * @param {boolean} [strict=false] whether or not partial names are resolved
     * @returns {array<GuildChannel> || false} an array of guild channels or false if none were resolved
     * @memberof Resolver
     */
    resolveChannels(resolveables = [], guild, strict = false) {

        if(typeof resolveables === 'string') resolveables = [ resolveables ];
        if(resolveables.length === 0) return false;
        const { channels } = guild;
        const resolved = [];

        for(const resolveable of resolveables) {

            const channel = channels.resolve(resolveable);
            if(channel) {
                resolved.push(channel);
                continue;
            }

            const name = /^#?([a-z0-9\-_0]*)/iu;
            const id = /^<#([0-9]*)>/iu;

            if (id.test(resolveable)) {

                const match = resolveable.match(id);
                const [, ch] = match;

                const channel = channels.resolve(ch);

                if (channel) resolved.push(channel);

            } else if (name.test(resolveable)) {

                const match = resolveable.match(name);
                const ch = match[1].toLowerCase();

                const [ channel ] = channels.cache.filter((c) => {
                    if(!strict) return c.name.toLowerCase().includes(ch);
                    return c.name.toLowerCase() === ch;
                }).first(1);

                if(channel) resolved.push(channel);

            } 

        }

        return resolved.length > 0 ? resolved : false;

    }
    
    resolveChannel(resolveable, guild, strict) {

        if (!resolveable) return false;
        const result = this.resolveChannels([resolveable], guild, strict);
        return result ? result[0] : false;

    }

    /**
     * Resolve multiple roles
     *
     * @param {array<string>} [resolveables=[]] an array of roles resolveables (name, id)
     * @param {Guild} guild the guild in which to look for roles
     * @param {boolean} [strict=false] whether or not partial names are resolved
     * @returns {array<GuildRole> || false} an array of roles or false if none were resolved
     * @memberof Resolver
     */
    async resolveRoles(resolveables = [], guild, strict = false) {

        if(typeof resolveables === 'string') resolveables = [ resolveables ];
        if(resolveables.length === 0) return false;
        const { roles } = guild;
        const resolved = [];

        for(const resolveable of resolveables) {

            const id = /^(<@&)?([0-9]{16,22})>?/iu;

            if(id.test(resolveable)) {

                const match = resolveable.match(id);
                const [,, rId] = match;

                const role = await roles.fetch(rId).catch(this.client.logger.error);

                if(role) resolved.push(role);

            } else {

                const role = roles.cache.filter((r) => {
                    if(!strict) return r.name.toLowerCase().includes(resolveable.toLowerCase());
                    return r.name.toLowerCase() === resolveable.toLowerCase();
                }).first();

                if(role) resolved.push(role);

            }

        }

        return resolved.length > 0 ? resolved : false;

    }

    async resolveRole(resolveable, guild, strict) {

        if (!resolveable) return false;
        const result = await this.resolveRoles([resolveable], guild, strict);
        return result ? result[0] : false;

    }
    
}

module.exports = Resolver;

const filterExact = (search) => (comp) => comp.id.toLowerCase() === search ||
        comp.resolveable.toLowerCase() === search ||
        comp.aliases && (comp.aliases.some((ali) => `${comp.type}:${ali}`.toLowerCase() === search) ||
        comp.aliases.some((ali) => ali.toLowerCase() === search));

const filterInexact = (search) => (comp) => comp.id.toLowerCase().includes(search) ||
        comp.resolveable.toLowerCase().includes(search) ||
        comp.aliases && (comp.aliases.some((ali) => `${comp.type}:${ali}`.toLowerCase().includes(search)) ||
        comp.aliases.some((ali) => ali.toLowerCase().includes(search)));