#!/usr/bin/env runts -- --allow-env --allow-run

import {
    execCommand,
    execCommandShell,
    existsPath,
    joinPath,
    log,
    readFileToString,
    resolveFilename,
} from "https://global.hatter.ink/script/get/@16/deno-commons-mod.ts";
import { parseArgs } from "jsr:@std/cli/parse-args";
import { writeStringToFile } from "../libraries/deno-commons-mod.ts";

const PYTHON_CONFIG_FILE = "~/.config/python-config.json";
const PYTHON_VENV_DEFAULT_BASE_DIR = "~/.venv/";

interface PythonConfig {
    default_version?: string;
    default_profile?: string;
    python_venv_base_path?: string;
    versions: Map<string, PythonVersion>;
    profiles?: Map<string, PythonVenv>;
}

interface PythonVersion {
    version: string;
    path: string; // Python path dir or Python binary file
    comment?: string;
}

interface PythonVenv {
    version: string;
    path: string;
    comment?: string;
}

async function loadPythonConfig(): Promise<PythonConfig> {
    const pythonConfigFile = resolveFilename(PYTHON_CONFIG_FILE);
    const pythonConfigJson = await readFileToString(pythonConfigFile);
    if (!pythonConfigJson) {
        throw `Could not read python config file: ${pythonConfigFile}`;
    }
    return JSON.parse(pythonConfigJson) as PythonConfig;
}

async function savePythonConfig(pythonConfig: PythonConfig): Promise<void> {
    const pythonConfigFile = resolveFilename(PYTHON_CONFIG_FILE);
    await writeStringToFile(
        pythonConfigFile,
        JSON.stringify(pythonConfig, null, 2),
    );
}

async function findVirtualEnv(pythonVenvVersion: string): Promise<PythonVenv> {
    const pythonConfig = await loadPythonConfig();
    if (!pythonConfig.profiles) {
        throw "No Python venvs configured";
    }
    const pythonVenv = pythonConfig.profiles[pythonVenvVersion];
    if (!pythonVenv) {
        throw `Python venv not found: ${pythonVenvVersion}`;
    }
    return pythonVenv;
}

async function newVirtualEnv(pythonVersion: string | null, pythonVenv: string) {
    const pythonConfig = await loadPythonConfig();
    const selectedPythonVersion = pythonVersion ||
        pythonConfig.default_version || null;
    if (!selectedPythonVersion) {
        throw `No Python version assigned.`;
    }
    if (!selectedPythonVersion) {
        throw `No Python venv assigned.`;
    }
    const pythonVersionProfile = pythonConfig.versions[pythonVersion];
    if (!pythonVersionProfile) {
        throw `Python version: ${pythonVersion} not found`;
    }
    log.success(`Found Python version: ${pythonVersion}`);
    const pythonVenvProfile = pythonConfig.profiles[pythonVenv];
    if (pythonVenvProfile) {
        throw `Python venv already exists: ${pythonVenv}`;
    }
    const pythonVenvBaseDir = resolveFilename(
        pythonConfig.python_venv_base_path || PYTHON_VENV_DEFAULT_BASE_DIR,
    );
    if (!existsPath(pythonVenvBaseDir)) {
        log.info(`Make python venv base dir: ${pythonVenvBaseDir}`);
        Deno.mkdirSync(pythonVenvBaseDir);
    }
    const pythonVenvDir = joinPath(pythonVenvBaseDir, pythonVenv);
    if (existsPath(pythonVenvDir)) {
        throw `Python venv: ${pythonVenvDir} already exists`;
    }

    // python3 -m venv myenv
    const python3Cmd = pythonVersionProfile.path;
    log.success(`Found Python: ${python3Cmd}`);
    const pythonVenvArgs = ["-m", "venv", pythonVenvDir];

    log.info(
        `Create Python venv, python: ${python3Cmd}, args: ${pythonVenvArgs}`,
    );
    await execCommandShell(python3Cmd, pythonVenvArgs);
}

async function isFile(path: string): Promise<boolean> {
    const fileInfo = await Deno.stat(path);
    return fileInfo?.isFile;
}

function handleHelp(_args: string[]) {
    const help = [];
    help.push(
        `python.ts - Python version and virtual environment management tool

python.ts python     - management python version [alias: py]
python.ts add-python - add python version [alias: py]
python.ts venv       - management python virtual environment`,
    );
    // source <(cat ~/.venv-python-3.13.5/bin/activate)
    // source <(python.ts venv test1)
    console.log(help.join("\n"));
}

async function handlePython(args: string[]) {
    const flags = parseArgs(Deno.args, {
        boolean: ["help"],
        string: ["version"],
        alias: {
            V: "version",
        },
    });
    if (flags.help) {
        console.log("Help massage for python");
        return;
    }
    if (!flags.version) {
        const pythonConfig = await loadPythonConfig();
        if (!pythonConfig.versions) {
            log.error("No Python versions configured");
            return;
        }

        const versions = [];
        let maxVersionLength = 0;
        for (let version in pythonConfig.versions) {
            versions.push(version);
            if (version.length > maxVersionLength) {
                maxVersionLength = version.length;
            }
        }
        versions.sort();

        console.log(`Found ${versions.length} Python version(s)`);
        for (let version in pythonConfig.versions) {
            const pythonVersion = pythonConfig.versions[version];
            const versionPadding = " ".repeat(
                maxVersionLength - version.length,
            );
            console.log(
                `- Python ${version} ${versionPadding}: ${pythonVersion.path} [version: ${
                    pythonVersion.version || "unknown"
                }]`,
            );
        }

        return;
    }
    const pythonVirtualEnv = await findVirtualEnv(flags.version);

    // TODO
}

async function getPythonVersion(pythonBinPath: string): Promise<string> {
    const pythonVersion = await execCommand(pythonBinPath, ["--version"]);
    const pythonVersionLower = pythonVersion.assertSuccess()
        .getStdoutAsStringThenTrim().toLowerCase();
    if (!pythonVersionLower.startsWith("python ")) {
        throw new Error(`Invalid Python version: ${pythonVersionLower}`);
    }
    return pythonVersionLower.substring("python ".length).trim();
}

async function handleAddPython(args: string[]) {
    const flags = parseArgs(Deno.args, {
        boolean: ["help"],
        string: ["path"],
    });
    if (flags.help) {
        console.log("Help massage for python add-python");
        return;
    }
    if (!flags.path) {
        throw new Error("Path is empty");
    }
    const path = flags.path as string;
    let pythonPath = path;
    if (!path.includes("/")) {
        const whichPath = await execCommand("which", [path]);
        pythonPath = whichPath.assertSuccess().getStdoutAsStringThenTrim();
    }
    log.info(`Python path: ${pythonPath}`);
    const isPythonPathFile = await isFile(pythonPath);
    let pythonBinPath = "";
    if (!isPythonPathFile) {
        const pythonPath1 = joinPath(pythonPath, "bin", "python3");
        if (await isFile(pythonPath1)) {
            pythonBinPath = pythonPath1;
        } else {
            const pythonPath2 = joinPath(pythonPath, "bin", "python");
            if (await isFile(pythonPath2)) {
                pythonBinPath = pythonPath2;
            } else {
                throw new Error(
                    `Python bin path not found, python path: ${pythonPath}`,
                );
            }
        }
    } else {
        pythonBinPath = pythonPath;
    }
    const pythonVersion = await getPythonVersion(pythonBinPath);
    log.info(`Python version: ${pythonVersion}`);

    const pythonConfig = await loadPythonConfig();

    if (!pythonConfig.versions) {
        pythonConfig.versions = {};
    }
    if (pythonConfig.versions[pythonVersion]) {
        throw new Error(`Python version ${pythonVersion} exists`);
    }
    const pyVersion: PythonVersion = {
        version: pythonVersion,
        path: pythonBinPath,
        comment: `Python v${pythonVersion}`,
    };
    log.info("Found Python version", pyVersion);
    pythonConfig.versions[pythonVersion] = pyVersion;

    log.info("Save to Python config");
    await savePythonConfig(pythonConfig);
}

async function handleVenv(args: string[]) {
    const flags = parseArgs(Deno.args, {
        boolean: ["help"],
        string: ["version"],
        alias: {
            V: "version",
        },
    });
    if (flags.help) {
        console.log("Help massage for venv");
        return;
    }
    if (!flags.version) {
        log.warn("Version missing");
        return;
    }
    const pythonVirtualEnv = await findVirtualEnv(flags.version);

    // TODO
}

async function main() {
    const args = parseArgs(Deno.args);
    const [subcommand, ...remainingArgs] = args._;

    if (!subcommand) {
        log.warn("Subcommand not found, `python.ts help` for help message");
        return;
    }

    switch (subcommand) {
        case "help":
            handleHelp(remainingArgs);
            break;
        case "py":
        case "python":
            await handlePython(remainingArgs);
            break;
        case "add-py":
        case "add-python":
            await handleAddPython(remainingArgs);
            break;
        case "venv":
            await handleVenv(remainingArgs);
            break;
        default:
            log.error(`Unknown subcommand: ${subcommand}`);
            break;
    }
}

main().catch((e) => log.error(e));