#pragma once

#include <optional>
#include <string>
#include <vector>

namespace fgc::paths {

// Expand a leading "~" (to $HOME) and any "$VAR" / "${VAR}" environment
// references in `path`. Returns the expanded path (unchanged if nothing to do).
std::string expandUser(const std::string& path);

// Absolute directory containing the running executable (via /proc/self/exe).
// Returns empty string if it cannot be determined.
std::string executableDir();

// The ordered list of locations searched for a config file, given an optional
// explicit --config argument. Exposed so callers can report what was tried.
std::vector<std::string> configSearchPaths(const std::string& cliArg = "");

// Resolve the config file path using configSearchPaths(): the first existing,
// readable file wins. Returns nullopt if none is found.
std::optional<std::string> resolveConfigPath(const std::string& cliArg = "");

// The ordered list of locations searched for hardware.ini - the assembly-time
// description of THIS machine (which board, which sensors are fitted, which
// device nodes they are on). Deliberately NOT derived from the config.ini path:
//
//   --hardware <path>                        explicit, for dev and testing
//   $FGC_HARDWARE                            the service environment
//   /etc/fire_gimbal_control/hardware.ini    the normal answer on a tower
//   <dir of config.ini>/hardware.ini         so a dev checkout just works
//
// /etc is where credentials.env already lives: root-owned, per-device, and
// OUTSIDE the deploy tree, so an rsync cannot overwrite or delete it. Keeping the
// assembly description there makes "a deploy never touches it" a property of
// where the file is, not of an exclude rule someone has to maintain.
std::vector<std::string> hardwareSearchPaths(const std::string& cliArg      = "",
                                             const std::string& configPath = "");

// Resolve hardware.ini using hardwareSearchPaths(); first existing file wins.
// Returns nullopt when there is none - which is not an error: the program then
// falls back to reading the assembly keys from config.ini as it always has.
std::optional<std::string> resolveHardwarePath(const std::string& cliArg      = "",
                                               const std::string& configPath = "");

// Default image output directory when none is configured
// ($XDG_DATA_HOME/fire_gimbal_control/images, else ~/.local/share/...).
std::string defaultOutputDir();

// Directory for diagnostic/calibration logfiles
// ($XDG_DATA_HOME/fire_gimbal_control/logs, else ~/.local/share/...).
std::string defaultLogDir();

// "<prefix>_YYYYMMDD-HHMMSS.log" using the local clock.
std::string timestampedLogName(const std::string& prefix);

// How many <prefix>_*.log reports to keep per kind. Generous: these are a few
// hundred bytes each and written by hand-run commands, so the cap is about
// keeping the directory greppable rather than about disk.
inline constexpr int kDefaultReportsKept = 50;

// Delete all but the `keep` newest "<prefix>_*.log" in defaultLogDir().
//
// Only files this program GENERATED are eligible: the name must be exactly
// "<prefix>_YYYYMMDD-HHMMSS.log", as timestampedLogName() builds it. A
// prefix-only match would also cover `[Test] baseline_file`, which is
// configurable and may live in this directory - the pinned reference every
// self-test compares against. keep <= 0 prunes nothing.
void pruneLogFiles(const std::string& prefix, int keep);

// Write `text` to `defaultLogDir()/<name>`, creating the directory if needed.
// Returns the full path written, or "" on failure (and logs a warning).
//
// Then prunes older files of the same kind, the prefix being whatever precedes
// the first '_' in `name` - so `test_*.log`, `diag_*.log` and `pitch_setup_*.log`
// stay bounded without each caller having to remember. Pass keep = 0 to opt out.
std::string writeLogFile(const std::string& name, const std::string& text,
                         int keep = kDefaultReportsKept);

}  // namespace fgc::paths