"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
/**
 * An operation that does nothing.
 */
class NoopChange {
    constructor() {
        this.description = 'No operation.';
        this.order = Infinity;
        this.path = null;
    }
    apply() { return Promise.resolve(); }
}
exports.NoopChange = NoopChange;
/**
 * Will add text to the source code.
 */
class InsertChange {
    constructor(path, pos, toAdd) {
        this.path = path;
        this.pos = pos;
        this.toAdd = toAdd;
        if (pos < 0) {
            throw new Error('Negative positions are invalid');
        }
        this.description = `Inserted ${toAdd} into position ${pos} of ${path}`;
        this.order = pos;
    }
    /**
     * This method does not insert spaces if there is none in the original string.
     */
    apply(host) {
        return host.read(this.path).then(content => {
            const prefix = content.substring(0, this.pos);
            const suffix = content.substring(this.pos);
            return host.write(this.path, `${prefix}${this.toAdd}${suffix}`);
        });
    }
}
exports.InsertChange = InsertChange;
/**
 * Will remove text from the source code.
 */
class RemoveChange {
    constructor(path, pos, toRemove) {
        this.path = path;
        this.pos = pos;
        this.toRemove = toRemove;
        if (pos < 0) {
            throw new Error('Negative positions are invalid');
        }
        this.description = `Removed ${toRemove} into position ${pos} of ${path}`;
        this.order = pos;
    }
    apply(host) {
        return host.read(this.path).then(content => {
            const prefix = content.substring(0, this.pos);
            const suffix = content.substring(this.pos + this.toRemove.length);
            // TODO: throw error if toRemove doesn't match removed string.
            return host.write(this.path, `${prefix}${suffix}`);
        });
    }
}
exports.RemoveChange = RemoveChange;
/**
 * Will replace text from the source code.
 */
class ReplaceChange {
    constructor(path, pos, oldText, newText) {
        this.path = path;
        this.pos = pos;
        this.oldText = oldText;
        this.newText = newText;
        if (pos < 0) {
            throw new Error('Negative positions are invalid');
        }
        this.description = `Replaced ${oldText} into position ${pos} of ${path} with ${newText}`;
        this.order = pos;
    }
    apply(host) {
        return host.read(this.path).then(content => {
            const prefix = content.substring(0, this.pos);
            const suffix = content.substring(this.pos + this.oldText.length);
            const text = content.substring(this.pos, this.pos + this.oldText.length);
            if (text !== this.oldText) {
                return Promise.reject(new Error(`Invalid replace: "${text}" != "${this.oldText}".`));
            }
            // TODO: throw error if oldText doesn't match removed string.
            return host.write(this.path, `${prefix}${this.newText}${suffix}`);
        });
    }
}
exports.ReplaceChange = ReplaceChange;
