#include "fgc/HelpText.h"

#include <algorithm>
#include <cctype>

namespace fgc {

namespace {

std::string lower(std::string s) {
    std::transform(s.begin(), s.end(), s.begin(),
                   [](unsigned char c) { return static_cast<char>(std::tolower(c)); });
    return s;
}

// First whitespace-delimited token of a syntax string (the command verb), lowercased.
std::string verbOf(const std::string& syntax) {
    auto end = syntax.find_first_of(" \t");
    return lower(syntax.substr(0, end == std::string::npos ? syntax.size() : end));
}

}  // namespace

const std::vector<HelpSection>& helpCatalog() {
    // clang-format off
    static const std::vector<HelpSection> catalog = {
        {"Modes", "What the tower is doing. MQTT StatusCode: 0 auto, 1 pan, 2 manual.", {
            {"mode", "Report the current mode.", {}},
            {"mode auto", "Sweep the scan grid, one image per waypoint (key a).", {
                "The unattended state; config [Startup] mode = auto boots into it.",
                "In auto and pan only status, logging, 'mode', 'cancel' and 'exit'",
                "are accepted."}},
            {"mode pan <heading> <span> [<pitch>]", "Sweep a span centred on a bearing, repeatedly (key p).", {
                "One image every pan_step_deg (hardware.ini), both edges included.",
                "Pitch defaults to 0 (level); a yaw-only tower ignores it. Key p pans",
                "30 deg around the current aim.",
                "Example:  mode pan 90 30"}},
            {"mode manual", "Stop scanning; aim by hand (key m). Cancels a running procedure.", {}},
        }},
        {"Capture", "Images and cameras. Manual mode, homed gimbal.", {
            {"snapshot", "Take one image now (key Space).", {
                "Waits for standstill and the exposure to settle, as a scan waypoint",
                "does, so the file and CamEvent are the same as a scan frame's."}},
            {"capture [on|off]", "Continuous capture where the gimbal is aimed (key r).", {
                "One image per [General] image_interval since the last, each once the",
                "gimbal stands still and the exposure has settled. The gimbal can still",
                "be nudged; images are kept only while it stands still. Bare 'capture'",
                "reports on/off. Ends on any mode change, homing, heading setup or test."}},
            {"set camera profile [<camera>] <name>", "Switch a camera's VimbaX settings profile.", {
                "<name> is an XML stem in that camera's profile_dir. The camera may be",
                "omitted when only one is configured.",
                "Example:  set camera profile night"}},
            {"camera reset", "Reboot the cameras and restore their profiles.", {
                "For a stream that has stopped and will not restart. Takes seconds."}},
        }},
        {"Positioning", "Yaw is a true bearing (0 = north); pitch is elevation (0 = level).", {
            {"gimbal move <yaw>[,<pitch>]", "Point at a bearing/elevation in degrees.", {
                "Bearings in the unreachable yaw arc are refused, not clamped.",
                "Without a pitch, only yaw moves. A yaw-only tower ignores the pitch",
                "and refuses the pitch-only commands below.",
                "Example:  gimbal move 30,-10   /   gimbal move 30"}},
            {"gimbal steps <yaw>[,<pitch>]", "Move to absolute encoder counts.", {
                "Example:  gimbal steps 100000,250000"}},
            {"gimbal nudge <yaw|pitch> <+/-pct>", "Relative move, percent of travel (arrow keys).", {
                "Example:  gimbal nudge yaw -5"}},
            {"gimbal jog <yaw|pitch> <+/-counts>", "Relative move in encoder counts.", {
                "Steps below ~13 counts are finer than the encoder resolves.",
                "Example:  gimbal jog yaw -25"}},
            {"gimbal home [y|p]", "Home both axes, or one.", {}},
            {"gimbal stop [y|p]", "Stop motion now (bare: every axis).", {}},
            {"gimbal heading setup|mark <deg>|fit|cancel", "Tie yaw to true north by sighting landmarks.", {
                "setup, then aim at a landmark and 'mark <its true bearing>'; repeat for",
                "at least two, far apart; then 'fit'. 'fit <counts>:<deg> ...' fits",
                "known pairs without a setup.",
                "Example:  gimbal heading mark 137.4"}},
            {"gimbal heading offset <deg>", "Shift the whole yaw map by a fixed amount.", {
                "Example:  gimbal heading offset -2.5"}},
            {"gimbal pitch setup", "Calibrate pitch against gravity (needs the IMU).", {
                "Homes if needed, sweeps pitch, fits, parks level and offers to save.",
                "Takes minutes; Esc or 'cancel' stops it."}},
        }},
        {"Motor", "Firmware-level motor controls.", {
            {"gimbal speed <y|p> <vel>", "Max slew speed, counts/s.", {}},
            {"gimbal current <y|p> <scaler> <irun> <irun_home>", "Motor current as raw TMC fields.", {
                "Normally set from hardware.ini [Motor.<axis>] in mA."}},
            {"gimbal reset|enable|disable <y|p>", "Reset, enable or disable an axis driver.", {}},
            {"gimbal setpos <y|p> <counts>", "Redefine an axis's current position.", {}},
            {"gimbal status", "Emit one telemetry line now.", {}},
            {"gimbal dump", "Fetch the firmware state; shown in the gimbal view (g).", {}},
            {"gimbal raw \"<command>\"", "Send text to the firmware verbatim.", {
                "Example:  gimbal raw \"MOVE 100000,250000\""}},
        }},
        {"IMU", "Xsens MTi orientation sensor.", {
            {"imu status", "Latest orientation reading (also in the sensors view, s).", {}},
            {"imu config", "Re-read and print the device configuration.", {}},
            {"imu profile [<type|label>]", "Select the XKF filter profile (bare: list them).", {
                "Persists on the device. Example:  imu profile General"}},
            {"imu zero", "Make the current pose yaw 0. Run 'imu norotation' first.", {}},
            {"imu norotation [<seconds>]", "Gyro-bias update; hold still (default 3 s).", {}},
        }},
        {"Tests", "Self-tests. Reports land in logs/test_*.log.", {
            {"test [<subsystem> [<leaf>]] [<profile>]", "Run the self-test suite, or part of it.", {
                "Compared with the pinned baseline and the previous run. Esc cancels.",
                "Example:  test gimbal homing   /   test list   /   test baseline"}},
            {"test hardware [axes|motor|imu|env|camera]", "Check the rig matches hardware.ini.", {}},
            {"test camera [frames|dark|bright]", "Check the camera delivers and responds.", {
                "Never judges the picture itself. Capture pauses meanwhile."}},
        }},
        {"Keys", "Dashboard shortcuts. Each sends the command shown.", {
            {"a / p / m", "mode auto / mode pan (30 deg around the aim) / mode manual.", {}},
            {"h", "gimbal home.", {}},
            {"Space / r", "snapshot / capture on|off.", {}},
            {"Arrows", "gimbal nudge: yaw 5%, pitch 10% if the tower has it (manual).", {}},
            {"Esc", "Close the view, or cancel a running procedure.", {}},
            {"? / g / s / c / n", "Views: help, gimbal, sensors, cameras, connectivity.", {}},
            {"PgUp / PgDn", "Scroll the log or the open view.", {}},
            {"f", "Freeze the screen, to select text or read back.", {}},
            {"q", "Quit, or leave the dashboard running in the background.", {}},
        }},
        {"Session", "Logging and exit.", {
            {"help [topic]", "This list; 'help <topic>' adds detail.", {
                "Example:  help capture   /   help positioning"}},
            {"cancel", "Cancel the running test, homing or calibration.", {}},
            {"debug", "Toggle debug-level logging.", {}},
            {"trace <serial|mqtt|camera|control|all|off> [on|off]", "Toggle wire-trace categories.", {
                "Example:  trace serial on"}},
            {"exit", "Shut down and quit.", {}},
        }},
    };
    // clang-format on
    return catalog;
}

std::vector<std::string> renderHelp(const std::string& topic) {
    std::vector<std::string> out;
    const std::string q = lower(topic);

    if (q.empty()) {
        // Summaries line up in one column; a syntax longer than the cap keeps its
        // own width rather than pushing every other line right.
        size_t width = 0;
        for (const auto& sec : helpCatalog())
            for (const auto& e : sec.entries) width = std::max(width, e.syntax.size());
        width = std::min<size_t>(width, 40);

        out.emplace_back("Commands ('help <topic>' for detail, e.g. 'help capture'):");
        for (const auto& sec : helpCatalog()) {
            out.emplace_back("");
            out.emplace_back(sec.title + " - " + sec.blurb);
            for (const auto& e : sec.entries) {
                std::string l = "  " + e.syntax;
                l.append(e.syntax.size() < width ? width - e.syntax.size() : 0, ' ');
                out.emplace_back(l + "  " + e.summary);
            }
        }
        return out;
    }

    // Topic mode: match a section by title, or an entry by command verb.
    bool matched = false;
    for (const auto& sec : helpCatalog()) {
        const bool sec_match = lower(sec.title).find(q) != std::string::npos;
        for (const auto& e : sec.entries) {
            if (!sec_match && verbOf(e.syntax) != q) continue;
            matched = true;
            out.emplace_back(e.syntax);
            out.emplace_back("    " + e.summary);
            for (const auto& d : e.detail) out.emplace_back("    " + d);
            out.emplace_back("");
        }
    }
    if (!matched) out.emplace_back("No help topic matching '" + topic + "'. Try 'help'.");
    return out;
}

}  // namespace fgc