const fs = require("fs");
const path = require("path");

const depts = {};

async function handle(filename) {
    // 找clzName
    const code = fs.readFileSync(filename);
    const inheritRegResult = /BI\.(.*?)\s=\sBI\.inherit\(/.exec(code);
    let clzName;
    if (inheritRegResult) {
        clzName = inheritRegResult[1];
    } else {
        const clzRegResult = /export\sclass\s(.*?)\sextend/.exec(code);
        if (clzRegResult) {
            clzName = clzRegResult[1];
        }
    }
    depts[clzName] = filename;
}

function isExist(filePath) {
    return fs.existsSync(filePath);
}

async function bfs(filename) {
    const stat = fs.statSync(filename);
    const isDir = stat.isDirectory();
    if (isDir) {
        const files = fs.readdirSync(filename);
        for (let i = 0; i < files.length; i++) {
            const file = files[i];
            await bfs(path.resolve(filename, file));
        }
    } else {
        await handle(filename);
    }
}

async function initDepts() {
    // dfs 构建依赖关系
    await bfs(path.resolve("src"));
}


function search(src, clzName) {
    if (!depts[clzName]) {
        return "";
    }

    const dstName = path.basename(depts[clzName]).replace(/.js$/g, "");
    const dstPath = path.normalize(depts[clzName]).split("src")[1].split("\\").join("/").split("/");
    const srcPath = path.normalize(src).split("src")[1].split("\\").join("/").split("/");

    // console.log("src", src);
    // console.log("dst", depts[clzName]);

    dstPath.shift();
    dstPath.pop();
    srcPath.shift();
    srcPath.pop();

    const findDstIndexPath = (dstArr, startIndex) => {
        let i = startIndex;

        while (!isExist(path.resolve("src", dstArr.slice(0, i + 1).join("/"), "index.js"))) {
            i++;
        }
        if (i < dstArr.length) {
            return dstArr.slice(startIndex, i + 1).join("/");
        } else {
            return `${dstArr.slice(startIndex).join("/")}/${dstName}`;
        }
    };

    // 不同包
    if (dstPath[0] !== srcPath[0]) {
        return `@/${dstPath[0]}`;
    }

    // 同包
    let i = 0;
    while (dstPath[i] === srcPath[i] && i < dstPath.length && i < srcPath.length) {
       i++;
    }

    if (i < srcPath.length) {
        let result = "";
        const rawI = i;
    
        // 回溯
        for (let j = 0; j < srcPath.length - rawI; j++) {
            result += "../";
            i--;
        }
        i++;
        // dstPath 也没有了
        if (i < dstPath.length) {
            return result + findDstIndexPath(dstPath, i);
            // 还有好多没有匹配完
            // while (i < srcPath) {
            //     // exists(srcPath.slice(0, i).join())
            //     result += srcPath[i];
            //     i++;
            // }
        } else if (i === dstPath.length) {
            return `${result}${dstName}`;
        }
    } else if (i === srcPath.length) {
        if (i === dstPath.length) {
            return dstName;
        } else if (i < dstPath.length) {
            return findDstIndexPath(dstPath, i);
        }
    }
}

// search(process.argv[2], "Text").then(res => {
//     console.log(res);
// });

exports.initDepts = initDepts;
exports.search = search;