// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

module Crafter.Review:Core_impl;
import :Core;
import :Platform;
import :Text;
import :Crypto;
import std;

namespace fs = std::filesystem;

namespace Crafter::Review {
    namespace {
        std::optional<fs::path>& HomeOverride() {
            static std::optional<fs::path> home;
            return home;
        }

        bool HoldsLenses(const fs::path& dir) {
            std::error_code error;
            return !dir.empty() && fs::is_directory(dir / "process" / "lenses", error);
        }

        fs::path FindHome() {
            if (!Platform::InSandbox()) {
                if (const std::optional<std::string> configured = Platform::GetEnv("CRAFTER_REVIEW_HOME"); configured && !configured->empty()) {
                    if (HoldsLenses(*configured)) return *configured;
                    throw std::runtime_error(std::format("CRAFTER_REVIEW_HOME={} holds no process/lenses", *configured));
                }
            }
            const fs::path exe = Platform::SelfExe();
            const fs::path installed = exe.parent_path().parent_path() / "share" / "crafter-review";
            if (HoldsLenses(installed)) return installed;
            // <checkout>/bin/crafter.review-exe-<variant>/crafter-review
            const fs::path variant = exe.parent_path();
            if (variant.filename().string().starts_with("crafter.review-exe-") && variant.parent_path().filename() == "bin") {
                const fs::path checkout = variant.parent_path().parent_path();
                if (HoldsLenses(checkout)) return checkout;
            }
            throw std::runtime_error(std::format("no process/lenses beside {} (neither {} nor a checkout's bin/): set CRAFTER_REVIEW_HOME", exe.string(), installed.string()));
        }
    }

    std::string_view Version() {
        return CRAFTER_REVIEW_VERSION;
    }

    std::string DriverLine() {
        return std::format("crafter-review {} (prompt v{})", Version(), PromptVersion);
    }

    const fs::path& Home() {
        if (!HomeOverride()) HomeOverride() = FindHome();
        return *HomeOverride();
    }

    void SetHome(fs::path home) {
        HomeOverride() = std::move(home);
    }

    fs::path LensDir() {
        return Home() / "process" / "lenses";
    }

    std::vector<std::pair<std::string, std::string>> CharterHashes() {
        std::vector<std::pair<std::string, std::string>> hashes;
        std::error_code error;
        for (const fs::directory_entry& entry : fs::directory_iterator(LensDir(), error)) {
            if (entry.path().extension() != ".md") continue;
            hashes.emplace_back(entry.path().filename().string(), Sha256Hex(Dyn::ReadText(entry.path())));
        }
        std::ranges::sort(hashes);
        return hashes;
    }
}