type CommentObjectType = "function" | "trigger" | "column" | "index";
export interface CommentParams {
    objectType: CommentObjectType;
    cacheSignature?: string;
    cacheSelect?: string;
    frozen?: boolean;
    legacyInfo?: Record<string, any>;
    migrationIsStarted?: boolean;
    migrationIsFinished?: boolean;
}

export class Comment {

    static empty(objectType: CommentObjectType) {
        return new Comment({
            objectType,
            frozen: false
        });
    }

    static frozen(objectType: CommentObjectType) {
        return new Comment({
            objectType,
            frozen: true
        });
    }

    static fromTotalString(objectType: CommentObjectType, total: string | null) {
        total = total || "";
        const frozen = (
            !total.includes("ddl-manager-sync") &&
            !total.includes("ddl-manager-helper")
        );
        const cacheSignature = parseCacheSignature(total);
        const cacheSelect = parseCacheSelect(total);
        const legacyInfo = parseLegacyInfo(total);
        const migrationIsStarted = total.includes("ddl-manager-migration-is-started") || undefined;
        const migrationIsFinished = total.includes("ddl-manager-migration-is-finished") || undefined;

        const comment = new Comment({
            objectType,
            frozen,
            cacheSignature,
            cacheSelect,
            legacyInfo,
            migrationIsStarted,
            migrationIsFinished
        });
        return comment;
    }

    static fromFs(params: CommentParams) {
        return new Comment({
            ...params,
            frozen: false
        });
    }

    readonly objectType: CommentObjectType;
    readonly frozen: boolean;
    readonly cacheSignature?: string;
    readonly cacheSelect?: string;
    readonly legacyInfo?: Readonly<Record<string, any>>;
    readonly migrationIsStarted?: boolean;
    readonly migrationIsFinished?: boolean;

    private constructor(params: CommentParams) {
        this.objectType = params.objectType;
        this.frozen = !!params.frozen;
        this.cacheSignature = params.cacheSignature;
        this.cacheSelect = params.cacheSelect;
        this.legacyInfo = params.legacyInfo;
        this.migrationIsStarted = params.migrationIsStarted;
        this.migrationIsFinished = params.migrationIsFinished;
    }

    isEmpty() {
        return this.frozen && !this.cacheSelect;
    }

    equal(otherComment: Comment) {
        return (
            this.cacheSelect == otherComment.cacheSelect &&
            this.cacheSignature == otherComment.cacheSignature
        );
    }

    markAsFrozen(legacyInfo: Record<string, any>) {
        return new Comment({
            ...this,
            frozen: true,
            legacyInfo
        });
    }

    hasNotFinishedMigration() {
        return this.migrationIsStarted && !this.migrationIsFinished;
    }


    startMigration() {
        return new Comment({
            ...this,
            migrationIsStarted: true,
            migrationIsFinished: false
        });
    }

    finishMigration() {
        return new Comment({
            ...this,
            migrationIsStarted: true,
            migrationIsFinished: true
        });
    }

    toString() {
        let comment = "";

        if ( !this.frozen ) {
            comment += "\nddl-manager-sync";
        }
        if ( this.cacheSelect ) {
            comment += `\nddl-manager-select(${ this.cacheSelect })`;
        }
        if ( this.cacheSignature ) {
            comment += `\nddl-manager-cache(${ this.cacheSignature })`;
        }
        if ( this.legacyInfo ) {
            comment += `\nddl-manager-legacy-info(${ JSON.stringify(this.legacyInfo) })`;
        }
        if ( this.migrationIsStarted ) {
            comment += `\nddl-manager-migration-is-started`;
        }
        if ( this.migrationIsFinished ) {
            comment += `\nddl-manager-migration-is-finished`;
        }

        return comment;
    }
}

function parseCacheSignature(totalComment: string) {
    const comment = (totalComment || "").trim();
    const matchedResult = comment.match(/ddl-manager-cache\(([^\\)]+)\)/) || [];
    const cacheSignature = matchedResult[1];
    return cacheSignature;
}

function parseCacheSelect(totalComment: string) {
    return extractContent({
        totalComment,
        codePhrase: "ddl-manager-select"
    });
}

function parseLegacyInfo(totalComment: string) {
    const legacyInfoStr = extractContent({
        totalComment,
        codePhrase: "ddl-manager-legacy-info"
    });
    if ( legacyInfoStr ) {
        try {
            return JSON.parse(legacyInfoStr);
        } catch {}
    }
}

function extractContent({
    totalComment, codePhrase
}: {
    codePhrase: string;
    totalComment: string
}) {
    const comment = (totalComment || "").trim();

    const startParsing = comment.indexOf(codePhrase + "(");
    if ( startParsing === -1 ) {
        return undefined;
    }

    let content = "";
    let openedBracketsCount = 1;
    for (let i = startParsing + codePhrase.length + 1; i < comment.length; i++) {
        const symbol = comment[i];

        if ( symbol === "(" ) {
            openedBracketsCount++;
        }
        if ( symbol === ")" ) {
            openedBracketsCount--;
            if ( openedBracketsCount === 0 ) {
                break;
            }
        }

        content += symbol;
    }

    return content;
}