import fs from 'fs';
import * as S from '../syntax/index.js';
import { ArrayList, Substitution } from '../syntax/index.js';
import * as G from './grammar.js';
import { BootProc } from './internals.js';

export function main(argv: string[]) {
    let [ inputFilename ] = argv.slice(2);
    inputFilename = inputFilename ?? '/dev/stdin';
    const source = fs.readFileSync(inputFilename, 'utf-8');

    const scanner = new S.StringScanner(S.startPos(inputFilename), source);
    const reader = new S.LaxReader(scanner);
    let tree = reader.readToEnd();
    let macro = new S.Templates();

    tree = macro.template()`import * as __SYNDICATE__ from '@syndicate/core';\n${tree}`;

    let passNumber = 1;
    let expansionNeeded = true;
    function expand<T>(p: S.Pattern<T>, f: (t: T) => S.Items) {
        tree = S.replace(tree, p, t => {
            expansionNeeded = true;
            return f(t);
        });
    }

    function receiverFor(s: G.FacetAction): Substitution {
        return (s.implicitFacet) ? 'thisFacet.' : '.';
    }

    function expandFacetAction<T extends G.FacetAction>(p: S.Pattern<T>, f: (t: T) => S.Items) {
        expand(p, t => macro.template()`${receiverFor(t)}${f(t)}`);
    }

    while (expansionNeeded) {
        if (passNumber >= 128) {
            throw new Error(`Too many compiler passes (${passNumber})!`);
        }
        expansionNeeded = false;
        expandFacetAction(
            G.spawn,
            s => {
                let proc = macro.template()`function (thisFacet) {${s.bootProcBody}}`;
                if (s.isDataspace) proc = macro.template()`__SYNDICATE__.inNestedDataspace(${proc})`;
                let assertions = (s.initialAssertions.length > 0)
                    ? macro.template()`, new __SYNDICATE__.Set([${S.joinItems(s.initialAssertions, ', ')}])`
                    : ``;
                return macro.template()`_spawn(${s.name ?? 'null'}, ${proc}${assertions});`;
            });
        expandFacetAction(
            G.fieldDeclarationStatement,
            s => {
                function isArrayProp(): [S.Substitution, S.Substitution] | null {
                    if (s.member.length === 0) return null;
                    const x = s.member[s.member.length - 1];
                    if (!S.isGroup(x)) return null;
                    if (x.start.text !== '[') return null;
                    return [s.member.slice(0, s.member.length - 1), x.items];
                }
                function isSimpleProp(): [S.Substitution, S.Substitution] | null {
                    if (s.member.length < 2) return null;
                    const r = S.value<G.Identifier>(o => S.seq(S.atom('.'), S.bind(o, 'value', G.identifier)))(
                        new ArrayList(s.member, s.member.length - 2));
                    if (r === null) return null;
                    const id = r[0];
                    return [s.member.slice(0, s.member.length - 2),
                            [ { start: id.start,
                                end: id.end,
                                type: S.TokenType.STRING,
                                text: JSON.stringify(id.text) } ]];
                }
                const [obj, prop] = isArrayProp()
                    ?? isSimpleProp()
                    ?? ["__SYNDICATE__.INVALID_PROPERTY_SYNTAX", "''"];
                return macro.template()`declareField(${obj}, ${prop}, ${s.expr ?? 'void 0'});`;
            });
        expandFacetAction(
            G.assertionEndpointStatement,
            s => macro.template()`addEndpoint(thisFacet => (${s.test ?? 'true'}) && (${s.template}), ${''+s.isDynamic});`);
        expandFacetAction(
            G.dataflowStatement,
            s => macro.template()`addDataflow(function (thisFacet) {${s.body}});`);
        expandFacetAction(
            G.eventHandlerEndpointStatement,
            s => {
                return macro.template()`EVENTHANDLER[${`${s.terminal}/${s.isDynamic}`}][${s.triggerType}][${s.pattern ?? []}][${s.body}]`;
            });
        expandFacetAction(
            G.duringStatement,
            s => macro.template()`DURING[${s.pattern}][${s.body}]`);
        expand(
            G.typeDefinitionStatement,
            s => {
                const l = JSON.stringify(s.label.text);
                const fs = JSON.stringify(s.fields.map(f => f.text));
                return macro.template()`const ${[s.label]} = __SYNDICATE__.Record.makeConstructor(${s.wireName ?? l}, ${fs});`;
            });
        expandFacetAction(
            G.messageSendStatement,
            s => macro.template()`_send(${s.expr});`);
        expandFacetAction(
            G.reactStatement,
            s => macro.template()`addChildFacet(function (thisFacet) {${s.body}});`);
        expand(
            G.bootStatement,
            s => macro.template()`export function ${BootProc}(thisFacet) {${s}}`);
        expandFacetAction(
            G.stopStatement,
            s => macro.template()`_stop(function (thisFacet) {${s.body}});`);
    }

    console.log(S.itemText(tree, { color: true, missing: '\x1b[41m□\x1b[0m' }));

    const cw = new S.CodeWriter(inputFilename);
    cw.emit(tree);
    fs.writeFileSync('/tmp/adhoc.syndicate', cw.text);
    const mm = cw.map;
    mm.sourcesContent = [source];
    fs.writeFileSync('/tmp/adhoc.syndicate.map', JSON.stringify(mm));
}