/*
 * Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
 */

#include <ox/fs/fs.hpp>
#include <ox/model/modelvalue.hpp>
#include <ox/std/utility.hpp>

#include <keel/media.hpp>

#include "pack.hpp"

namespace keel {

static ox::Error pathToInode(
		[[maybe_unused]] keel::Context *ctx, ox::FileSystem *dest, ox::ModelObject *obj) noexcept {
	auto &o = *obj;
	auto type = static_cast<ox::FileAddressType>(o["type"].get<int8_t>());
	auto &data = o["data"].get<ox::ModelUnion>();
	ox::String path;
	switch (type) {
		case ox::FileAddressType::Path:
			path = data["path"].get<ox::String>();
			break;
		case ox::FileAddressType::ConstPath:
			path = data["constPath"].get<ox::String>();
			break;
		case ox::FileAddressType::Inode:
		case ox::FileAddressType::None:
			return {};
	}
	if (beginsWith(path, "uuid://")) {
#ifndef OX_BARE_METAL
		const auto uuid = ox::StringView(path).substr(7);
		path = ctx->uuidToPath[uuid];
#else
		return OxError(1, "UUID to path conversion not supported on this platform");
#endif
	}
	oxRequire(s, dest->stat(path));
	oxReturnError(o["type"].set(static_cast<int8_t>(ox::FileAddressType::Inode)));
	return data.set(2, s.inode);
}

static ox::Error transformFileAddressesObj(keel::Context *ctx, ox::FileSystem *dest, ox::ModelObject *obj) noexcept;
static ox::Error transformFileAddressesVec(keel::Context *ctx, ox::FileSystem *dest, ox::ModelValueVector *v) noexcept;

static ox::Error transformFileAddresses(keel::Context *ctx, ox::FileSystem *dest, ox::ModelValue *v) noexcept {
	if (v->type() == ox::ModelValue::Type::Object) {
		auto &obj = v->get<ox::ModelObject>();
		return transformFileAddressesObj(ctx, dest, &obj);
	} else if (v->type() == ox::ModelValue::Type::Vector) {
		auto &vec = v->get<ox::ModelValueVector>();
		return transformFileAddressesVec(ctx, dest, &vec);
	}
	return {};
}

static ox::Error transformFileAddressesVec(keel::Context *ctx, ox::FileSystem *dest, ox::ModelValueVector *v) noexcept {
	for (auto &f : *v) {
		oxReturnError(transformFileAddresses(ctx, dest, &f));
	}
	return {};
}

/**
 * Convert path references in Claw data to inodes to save space
 * @return error
 */
static ox::Error transformFileAddressesObj(keel::Context *ctx, ox::FileSystem *dest, ox::ModelObject *obj) noexcept {
	if (obj->typeName() == "net.drinkingtea.ox.FileAddress" && obj->typeVersion() == 1) {
		return pathToInode(ctx, dest, obj);
	}
	for (auto &f : *obj) {
		auto &v = f->value;
		oxReturnError(transformFileAddresses(ctx, dest, &v));
	}
	return {};
}

static ox::Error doTransformations(
		[[maybe_unused]] keel::Context *ctx,
		[[maybe_unused]] ox::TypeStore *ts,
		[[maybe_unused]] ox::FileSystem *dest,
		[[maybe_unused]] ox::CRStringView filePath) noexcept {
#ifndef OX_BARE_METAL
	// load file
	oxRequire(s, dest->stat(filePath));
	// do transformations
	oxRequireM(buff, dest->read(s.inode));
	for (auto tr : ctx->packTransforms) {
		oxReturnError(tr(ctx, &buff));
	}
	// transform FileAddresses
	oxRequireM(obj, keel::readAsset(ts, buff));
	oxReturnError(transformFileAddressesObj(ctx, dest, &obj));
	oxReturnError(ox::writeClaw(obj).moveTo(&buff));
	// write file to dest
	oxReturnError(dest->write(s.inode, buff.data(), buff.size()));
	return {};
#else
	return OxError(1, "Transformations not supported on this platform");
#endif
}

// claw file transformations are broken out from copy because path to inode
// transformations need to be done after the copy to the new FS is complete
static ox::Error transformClaw(keel::Context *ctx, ox::TypeStore *ts, ox::FileSystem *dest, ox::CRStringView path) noexcept {
	// copy
	oxTracef("pack::transformClaw", "path: {}", path);
	oxRequire(fileList, dest->ls(path));
	for (const auto &name : fileList) {
		const auto filePath = ox::sfmt("{}{}", path, name);
		oxRequire(stat, dest->stat(filePath));
		if (stat.fileType == ox::FileType::Directory) {
			const auto dir = ox::sfmt("{}{}/", path, name);
			oxReturnError(transformClaw(ctx, ts, dest, dir));
		} else {
			oxReturnError(doTransformations(ctx, ts, dest, filePath));
		}
	}
	return {};
}

static ox::Error verifyFile(ox::FileSystem *fs, ox::CRStringView path, const ox::Buffer &expected) noexcept {
	ox::Buffer buff(expected.size());
	oxReturnError(fs->read(path, buff.data(), buff.size()));
	return OxError(buff == expected ? 0 : 1);
}

struct VerificationPair {
	ox::String path;
	ox::Buffer buff;
	VerificationPair(ox::String &&pPath, ox::Buffer &&pBuff) noexcept:
		path(ox::forward<ox::String>(pPath)),
		buff(ox::forward<ox::Buffer>(pBuff)) {
	}
};

static ox::Error copy(ox::FileSystem *src, ox::FileSystem *dest, ox::CRStringView path, ox::Vector<VerificationPair> *verificationPairs) noexcept {
	oxOutf("copying directory: {}\n", path);
	// copy
	oxRequire(fileList, src->ls(path));
	for (const auto &name : fileList) {
		auto currentFile = ox::sfmt("{}{}", path, name);
		if (beginsWith(name, ".")) {
			continue;
		}
		oxOutf("reading {}\n", currentFile);
		oxRequire(stat, src->stat(currentFile));
		if (stat.fileType == ox::FileType::Directory) {
			oxReturnError(dest->mkdir(currentFile, true));
			oxReturnError(copy(src, dest, currentFile + '/', verificationPairs));
		} else {
			// load file
			oxRequireM(buff, src->read(currentFile));
			// write file to dest
			oxOutf("writing {}\n", currentFile);
			oxReturnError(dest->write(currentFile, buff.data(), buff.size()));
			oxReturnError(verifyFile(dest, currentFile, buff));
			verificationPairs->emplace_back(std::move(currentFile), std::move(buff));
		}
	}
	return {};
}

static ox::Error copyFS(ox::FileSystem *src, ox::FileSystem *dest) noexcept {
	ox::Vector<VerificationPair> verificationPairs;
	oxReturnError(copy(src, dest, "/", &verificationPairs));
	// verify all at once in addition to right after the files are written
	oxOut("Verifying completed destination\n");
	for (const auto &v : verificationPairs) {
		oxReturnError(verifyFile(dest, v.path, v.buff));
	}
	return {};
}

ox::Error pack(keel::Context *ctx, ox::TypeStore *ts, ox::FileSystem *dest) noexcept {
	oxReturnError(copyFS(ctx->rom.get(), dest));
	oxOut("Doing transforms\n");
	oxReturnError(transformClaw(ctx, ts, dest, "/"));
	return {};
}

}