#include "common.h"
#include "files.h"
#include "handles.h"
#include <algorithm>
#include <cctype>
#include <map>
#include <optional>
#include <strings.h>
#include <string>

namespace files {

	static std::vector<std::string> splitList(const std::string &value, char delimiter) {
		std::vector<std::string> entries;
		size_t start = 0;
		while (start <= value.size()) {
			size_t end = value.find(delimiter, start);
			if (end == std::string::npos) {
				end = value.size();
			}
			entries.emplace_back(value.substr(start, end - start));
			if (end == value.size()) {
				break;
			}
			start = end + 1;
		}
		return entries;
	}

	static std::string toWindowsPathEntry(const std::string &entry) {
		if (entry.empty()) {
			return std::string();
		}
		bool looksWindows = entry.find('\\') != std::string::npos ||
					(entry.size() >= 2 && entry[1] == ':' && entry[0] != '/');
		if (looksWindows) {
			std::string normalized = entry;
			std::replace(normalized.begin(), normalized.end(), '/', '\\');
			return normalized;
		}
		return pathToWindows(std::filesystem::path(entry));
	}

	static std::string toHostPathEntry(const std::string &entry) {
		if (entry.empty()) {
			return std::string();
		}
		auto converted = pathFromWindows(entry.c_str());
		if (!converted.empty()) {
			return converted.string();
		}
		std::string normalized = entry;
		std::replace(normalized.begin(), normalized.end(), '\\', '/');
		return normalized;
	}

	static void *stdinHandle;
	static void *stdoutHandle;
	static void *stderrHandle;

	std::filesystem::path pathFromWindows(const char *inStr) {
		// Convert to forward slashes
		std::string str = inStr;
		std::replace(str.begin(), str.end(), '\\', '/');

		// Remove "//?/" prefix
		if (str.rfind("//?/", 0) == 0) {
			str.erase(0, 4);
		}

		// Remove the drive letter
		if (str.rfind("z:/", 0) == 0 || str.rfind("Z:/", 0) == 0) {
			str.erase(0, 2);
		}

		// Return as-is if it exists, else traverse the filesystem looking for
		// a path that matches case insensitively
		std::filesystem::path path = std::filesystem::path(str).lexically_normal();
		if (std::filesystem::exists(path)) {
			return path;
		}

		std::filesystem::path newPath = ".";
		bool followingExisting = true;
		for (const auto& component : path) {
			std::filesystem::path newPath2 = newPath / component;
			if (followingExisting && !std::filesystem::exists(newPath2) && (component != ".." && component != "." && component != "")) {
				followingExisting = false;
				try {
					for (std::filesystem::path entry : std::filesystem::directory_iterator{newPath}) {
						if (strcasecmp(entry.filename().c_str(), component.c_str()) == 0) {
							followingExisting = true;
							newPath2 = entry;
							break;
						}
					}
				} catch (const std::filesystem::filesystem_error&) {
					// not a directory
				}
			}
			newPath = newPath2;
		}
		if (followingExisting) {
			DEBUG_LOG("Resolved case-insensitive path: %s\n", newPath.c_str());
		} else {
			DEBUG_LOG("Failed to resolve path: %s\n", newPath.c_str());
		}

		return newPath;
	}

	std::string pathToWindows(const std::filesystem::path &path) {
		std::string str = path.lexically_normal();

		if (path.is_absolute()) {
			str.insert(0, "Z:");
		}

		std::replace(str.begin(), str.end(), '/', '\\');
		return str;
	}

	FILE *fpFromHandle(void *handle, bool pop) {
		handles::Data data = handles::dataFromHandle(handle, pop);
		if (data.type == handles::TYPE_FILE) {
			return (FILE*)data.ptr;
		} else if (data.type == handles::TYPE_UNUSED && pop) {
			return 0;
		} else {
			printf("Invalid file handle %p\n", handle);
			assert(0);
		}
	}

	void *allocFpHandle(FILE *fp) {
		return handles::allocDataHandle(handles::Data{handles::TYPE_FILE, fp, 0});
	}

	void *getStdHandle(uint32_t nStdHandle) {
		switch (nStdHandle) {
			case ((uint32_t) -10): // STD_INPUT_HANDLE
				return stdinHandle;
			case ((uint32_t) -11): // STD_OUTPUT_HANDLE
				return stdoutHandle;
			case ((uint32_t) -12): // STD_ERROR_HANDLE
				return stderrHandle;
			default:
				return (void *) 0xFFFFFFFF;
		}
	}

	unsigned int setStdHandle(uint32_t nStdHandle, void *hHandle) {
		switch (nStdHandle) {
			case ((uint32_t) -10): // STD_INPUT_HANDLE
				stdinHandle = hHandle;
				break;
			case ((uint32_t) -11): // STD_OUTPUT_HANDLE
				stdoutHandle = hHandle;
				break;
			case ((uint32_t) -12): // STD_ERROR_HANDLE
				stderrHandle = hHandle;
				break;
			default:
				return 0; // fail
		}
		return 1; // success
	}

	void init() {
		stdinHandle = allocFpHandle(stdin);
		stdoutHandle = allocFpHandle(stdout);
		stderrHandle = allocFpHandle(stderr);
	}

	std::optional<std::filesystem::path> findCaseInsensitiveFile(const std::filesystem::path &directory,
														 const std::string &filename) {
		std::error_code ec;
		if (directory.empty()) {
			return std::nullopt;
		}
		if (!std::filesystem::exists(directory, ec) || !std::filesystem::is_directory(directory, ec)) {
			return std::nullopt;
		}
		std::string needle = filename;
		std::transform(needle.begin(), needle.end(), needle.begin(), [](unsigned char ch) { return std::tolower(ch); });
		for (const auto &entry : std::filesystem::directory_iterator(directory, ec)) {
			if (ec) {
				break;
			}
			std::string candidate = entry.path().filename().string();
			std::transform(candidate.begin(), candidate.end(), candidate.begin(), [](unsigned char ch) { return std::tolower(ch); });
			if (candidate == needle) {
				return canonicalPath(entry.path());
			}
		}
		auto direct = directory / filename;
		if (std::filesystem::exists(direct, ec)) {
			return canonicalPath(direct);
		}
		return std::nullopt;
	}

	std::filesystem::path canonicalPath(const std::filesystem::path &path) {
		std::error_code ec;
		auto canonical = std::filesystem::weakly_canonical(path, ec);
		if (!ec) {
			return canonical;
		}
		return std::filesystem::absolute(path);
	}

	std::string hostPathListToWindows(const std::string &value) {
		if (value.empty()) {
			return value;
		}
		char delimiter = value.find(';') != std::string::npos ? ';' : ':';
		auto entries = splitList(value, delimiter);
		std::string result;
		for (size_t i = 0; i < entries.size(); ++i) {
			if (i != 0) {
				result.push_back(';');
			}
			if (!entries[i].empty()) {
				result += toWindowsPathEntry(entries[i]);
			}
		}
		return result;
	}

	std::string windowsPathListToHost(const std::string &value) {
		if (value.empty()) {
			return value;
		}
		auto entries = splitList(value, ';');
		std::string result;
		for (size_t i = 0; i < entries.size(); ++i) {
			if (i != 0) {
				result.push_back(':');
			}
			if (!entries[i].empty()) {
				result += toHostPathEntry(entries[i]);
			}
		}
		return result;
	}
}