/**
 * https://github.com/kawanet/git-cat-file
 */

import type {GCF} from "../types/git-cat-file.d.ts"
import {ObjItem} from "./obj-item.ts"
import type {ObjStore} from "./obj-store.ts"
import {Tree} from "./tree.ts"

export class Commit extends ObjItem<GCF.CommitMeta> implements GCF.Commit {
    constructor(obj: GCF.IObject, store: ObjStore) {
        super(obj, store)

        if (obj.type !== "commit" && obj.type !== "tag") {
            throw new TypeError(`Invalid commit object: ${obj.oid} (${obj.type})`)
        }
    }

    getDate(): Date {
        const author = this.getMeta("author") || this.getMeta("committer")
        const match = author?.match(/\s+(\d+)(\s+[+\-]\d+)?$/)
        if (match) return new Date(+match[1] * 1000)
    }

    async getTree(): Promise<GCF.Tree> {
        const oid = this.getMeta("tree")
        const obj = await this.store.getObject(oid)
        return new Tree(obj, this.store)
    }

    async getFile(path: string): Promise<GCF.File> {
        const tree = await this.getTree()
        const entry = await tree.getEntry(path)
        if (!entry) return

        const {oid, mode} = entry
        const obj = await this.store.getObject(oid)
        if (obj.type !== "blob") return

        const {data} = obj
        return {oid, mode, data}
    }

    async getParents(): Promise<GCF.Commit[]> {
        const parent = this.getMetaArray("parent")
        if (!parent) return

        const array: GCF.Commit[] = []
        for (const oid of parent) {
            const obj = await this.store.getObject(oid)
            if (obj) array.push(new Commit(obj, this.store))
        }
        return array
    }
}