#include "../GCode.hpp"
#include "CoolingBuffer.hpp"
#include <boost/algorithm/string/predicate.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <iostream>
#include <float.h>

#if 0
    #define DEBUG
    #define _DEBUG
    #undef NDEBUG
#endif

#include <assert.h>

namespace Slic3r {

CoolingBuffer::CoolingBuffer(GCode &gcodegen) : m_gcodegen(gcodegen), m_current_extruder(0)
{
    this->reset();
}

void CoolingBuffer::reset()
{
    m_current_pos.assign(5, 0.f);
    Pointf3 pos = m_gcodegen.writer().get_position();
    m_current_pos[0] = float(pos.x);
    m_current_pos[1] = float(pos.y);
    m_current_pos[2] = float(pos.z);
    m_current_pos[4] = float(m_gcodegen.config().travel_speed.value);
}

#define EXTRUDER_CONFIG(OPT) config.OPT.get_at(m_current_extruder)

std::string CoolingBuffer::process_layer(const std::string &gcode, size_t layer_id)
{
    const FullPrintConfig &config        = m_gcodegen.config();
    const auto            &elapsed_times = m_gcodegen.writer().elapsed_times();
    const size_t           num_extruders = elapsed_times.size();

    // Calculate the required per extruder time stretches.
    struct Adjustment {
        Adjustment() {}
        // Calculate the total elapsed time per this extruder, adjusted for the slowdown.
        float elapsed_time_total() {
            float time_total = 0.f;
            for (const Line &line : lines)
                time_total += line.time;
            return time_total;
        }
        // Calculate the maximum time when slowing down.
        float maximum_time(bool slowdown_external_perimeters) {
            float time_total = 0.f;
			for (const Line &line : lines)
				if (line.adjustable(slowdown_external_perimeters)) {
					if (line.time_max == FLT_MAX)
						return FLT_MAX;
					else
						time_total += line.time_max;
				} else
					time_total += line.time;
            return time_total;
        }
        // Calculate the non-adjustable part of the total time.
        float non_adjustable_time(bool slowdown_external_perimeters) {
            float time_total = 0.f;
            for (const Line &line : lines)
                if (! line.adjustable(slowdown_external_perimeters))
                    time_total += line.time;
            return time_total;
        }
        float slow_down_maximum(bool slowdown_external_perimeters) {
            float time_total = 0.f;
            for (Line &line : lines) {
                if (line.adjustable(slowdown_external_perimeters)) {
					assert(line.time_max >= 0.f && line.time_max < FLT_MAX);
                    line.slowdown = true;
                    line.time = line.time_max;
                }
                time_total += line.time;
            }
            return time_total;
        }
        float slow_down_proportional(float factor, bool slowdown_external_perimeters) {
            assert(factor >= 1.f);
            float time_total = 0.f;
            for (Line &line : lines) {
                if (line.adjustable(slowdown_external_perimeters)) {
                    line.slowdown = true;
                    line.time = std::min(line.time_max, line.time * factor);
                }
                time_total += line.time;
            }
            return time_total;
        }

        struct Line
        {
            enum Type {
                TYPE_SET_TOOL           = 1 << 0,
                TYPE_EXTRUDE_END        = 1 << 1,
                TYPE_BRIDGE_FAN_START   = 1 << 2,
                TYPE_BRIDGE_FAN_END     = 1 << 3,
                TYPE_G0                 = 1 << 4,
                TYPE_G1                 = 1 << 5,
                TYPE_ADJUSTABLE         = 1 << 6,
                TYPE_EXTERNAL_PERIMETER = 1 << 7,
                TYPE_WIPE               = 1 << 8,
                TYPE_G4                 = 1 << 9,
                TYPE_G92                = 1 << 10,
            };

            Line(unsigned int type, size_t  line_start, size_t  line_end) :
                type(type), line_start(line_start), line_end(line_end),
                length(0.f), time(0.f), time_max(0.f), slowdown(false) {}

            bool adjustable(bool slowdown_external_perimeters) const {
                return (this->type & TYPE_ADJUSTABLE) && 
                       (! (this->type & TYPE_EXTERNAL_PERIMETER) || slowdown_external_perimeters) &&
                       this->time < this->time_max;
            }

            size_t  type;
            // Start of this line at the G-code snippet.
            size_t  line_start;
            // End of this line at the G-code snippet.
            size_t  line_end;
            // XY Euclidian length of this segment.
            float   length;
            // Current duration of this segment.
            float   time;
            // Maximum duration of this segment.
            float   time_max;
            // If marked with the "slowdown" flag, the line has been slowed down.
            bool    slowdown;
        };

        // Parsed lines.
        std::vector<Line>   lines;
    };
    std::vector<Adjustment> adjustments(num_extruders, Adjustment());
    const std::string       toolchange_prefix = m_gcodegen.writer().toolchange_prefix();
    // Parse the layer G-code for the moves, which could be adjusted.
    {
        float             min_print_speed   = float(EXTRUDER_CONFIG(min_print_speed));
        auto              it_elapsed_time   = std::lower_bound(elapsed_times.begin(), elapsed_times.end(), ElapsedTime(m_current_extruder));
        Adjustment       *adjustment        = &adjustments[it_elapsed_time - elapsed_times.begin()];
        unsigned int      initial_extruder  = m_current_extruder;
		const char       *line_start = gcode.c_str();
		const char		 *line_end   = line_start;
        const char        extrusion_axis = config.get_extrusion_axis()[0];
        // Index of an existing Adjustment::Line of the current adjustment, which holds the feedrate setting command
        // for a sequence of extrusion moves.
        size_t            active_speed_modifier = size_t(-1);
		for (; *line_start != 0; line_start = line_end) {
            while (*line_end != '\n' && *line_end != 0)
                ++ line_end;
            std::string sline(line_start, line_end);
            Adjustment::Line line(0, line_start - gcode.c_str(), line_end - gcode.c_str());
            if (boost::starts_with(sline, "G0 "))
                line.type = Adjustment::Line::TYPE_G0;
            else if (boost::starts_with(sline, "G1 "))
                line.type = Adjustment::Line::TYPE_G1;
            else if (boost::starts_with(sline, "G92 "))
                line.type = Adjustment::Line::TYPE_G92;
            if (line.type) {
                // G0, G1 or G92
                // Parse the G-code line.
                std::vector<float> new_pos(m_current_pos);
                const char *c = sline.data() + 3;
                for (;;) {
                    // Skip whitespaces.
                    for (; *c == ' ' || *c == '\t'; ++ c);
                    if (*c == 0 || *c == ';')
                        break;
                    // Parse the axis.
                    size_t axis = (*c >= 'X' && *c <= 'Z') ? (*c - 'X') :
                                  (*c == extrusion_axis) ? 3 : (*c == 'F') ? 4 : size_t(-1);
					if (axis != size_t(-1)) {
						new_pos[axis] = float(atof(++c));
						if (axis == 4)
							// Convert mm/min to mm/sec.
							new_pos[4] /= 60.f;
					}
                    // Skip this word.
                    for (; *c != ' ' && *c != '\t' && *c != 0; ++ c);
                }
                bool external_perimeter = boost::contains(sline, ";_EXTERNAL_PERIMETER");
                bool wipe               = boost::contains(sline, ";_WIPE");
                if (external_perimeter)
                    line.type |= Adjustment::Line::TYPE_EXTERNAL_PERIMETER;
                if (wipe)
                    line.type |= Adjustment::Line::TYPE_WIPE;
                if (boost::contains(sline, ";_EXTRUDE_SET_SPEED") && ! wipe) {
                    line.type |= Adjustment::Line::TYPE_ADJUSTABLE;
                    active_speed_modifier = adjustment->lines.size();
                }
                if ((line.type & Adjustment::Line::TYPE_G92) == 0) {
                    // G0 or G1. Calculate the duration.
                    if (config.use_relative_e_distances.value)
                        // Reset extruder accumulator.
                        m_current_pos[3] = 0.f;
                    float dif[4];
                    for (size_t i = 0; i < 4; ++ i)
                        dif[i] = new_pos[i] - m_current_pos[i];
                    float dxy2 = dif[0] * dif[0] + dif[1] * dif[1];
                    float dxyz2 = dxy2 + dif[2] * dif[2];
                    if (dxyz2 > 0.f) {
                        // Movement in xyz, calculate time from the xyz Euclidian distance.
                        line.length = sqrt(dxyz2);
                    } else if (std::abs(dif[3]) > 0.f) {
                        // Movement in the extruder axis.
                        line.length = std::abs(dif[3]);
                    }
                    if (line.length > 0)
                        line.time   = line.length / new_pos[4]; // current F
                    line.time_max = line.time;
					if ((line.type & Adjustment::Line::TYPE_ADJUSTABLE) || active_speed_modifier != size_t(-1))
                        line.time_max = (min_print_speed == 0.f) ? FLT_MAX : std::max(line.time, line.length / min_print_speed);
					if (active_speed_modifier < adjustment->lines.size() && (line.type & Adjustment::Line::TYPE_G1)) {
						Adjustment::Line &sm = adjustment->lines[active_speed_modifier];
						sm.length   += line.length;
						sm.time     += line.time;
						if (sm.time_max != FLT_MAX) {
							if (line.time_max == FLT_MAX)
								sm.time_max = FLT_MAX;
							else
								sm.time_max += line.time_max;
						}
						// Don't store this line.
						line.type = 0;
					}
				}
                m_current_pos = std::move(new_pos);
            } else if (boost::starts_with(sline, ";_EXTRUDE_END")) {
                line.type = Adjustment::Line::TYPE_EXTRUDE_END;
                active_speed_modifier = size_t(-1);
            } else if (boost::starts_with(sline, toolchange_prefix)) {
                // Switch the tool.
                unsigned int new_extruder = (unsigned int)atoi(sline.c_str() + toolchange_prefix.size());
                if (new_extruder != m_current_extruder) {
                    m_current_extruder = new_extruder;
                    min_print_speed    = float(EXTRUDER_CONFIG(min_print_speed));
                    it_elapsed_time    = std::lower_bound(elapsed_times.begin(), elapsed_times.end(), ElapsedTime(m_current_extruder));
                    adjustment         = &adjustments[it_elapsed_time - elapsed_times.begin()];
                }
            } else if (boost::starts_with(sline, ";_BRIDGE_FAN_START")) {
                line.type = Adjustment::Line::TYPE_BRIDGE_FAN_START;
            } else if (boost::starts_with(sline, ";_BRIDGE_FAN_END")) {
                line.type = Adjustment::Line::TYPE_BRIDGE_FAN_END;
            } else if (boost::starts_with(sline, "G4 ")) {
                // Parse the wait time.
                line.type = Adjustment::Line::TYPE_G4;
                size_t pos_S = sline.find('S', 3);
                size_t pos_P = sline.find('P', 3);
                line.time = line.time_max = float(
                    (pos_S > 0) ? atof(sline.c_str() + pos_S + 1) :
                    (pos_P > 0) ? atof(sline.c_str() + pos_P + 1) * 0.001 : 0.);
            }
            if (line.type != 0)
                adjustment->lines.emplace_back(std::move(line));
			while (*line_end == '\n')
				++ line_end;
		}
        m_current_extruder = initial_extruder;
    }

    // Sort the extruders by the increasing slowdown_below_layer_time.
    std::vector<size_t> by_slowdown_layer_time;
    by_slowdown_layer_time.reserve(num_extruders);
    // Only insert entries, which are adjustable (have cooling enabled and non-zero stretchable time).
    // Collect total print time of non-adjustable extruders.
    float elapsed_time_total_non_adjustable = 0.f;
    for (size_t i = 0; i < num_extruders; ++ i) {
        if (config.cooling.get_at(elapsed_times[i].extruder_id))
            by_slowdown_layer_time.emplace_back(i);
        else
            elapsed_time_total_non_adjustable += adjustments[i].elapsed_time_total();
    }
    std::sort(by_slowdown_layer_time.begin(), by_slowdown_layer_time.end(),
        [&config, &elapsed_times](const size_t idx1, const size_t idx2){
            return config.slowdown_below_layer_time.get_at(elapsed_times[idx1].extruder_id) < 
                   config.slowdown_below_layer_time.get_at(elapsed_times[idx2].extruder_id);
        });

    // Elapsed time after adjustment.
    float elapsed_time_total = 0.f;
    {
        // Elapsed time for the already adjusted extruders.
		float elapsed_time_total0 = elapsed_time_total_non_adjustable;
        for (size_t i_by_slowdown_layer_time = 0; i_by_slowdown_layer_time < by_slowdown_layer_time.size(); ++ i_by_slowdown_layer_time) {
            // Idx in elapsed_times and adjustments.
            size_t idx = by_slowdown_layer_time[i_by_slowdown_layer_time];
            // Macro to sum or adjust all sections starting with i_by_slowdown_layer_time.
            #define FORALL_UNPROCESSED(ACCUMULATOR, ACTION) \
                ACCUMULATOR = elapsed_time_total0;\
                for (size_t j = i_by_slowdown_layer_time; j < by_slowdown_layer_time.size(); ++ j) \
                    ACCUMULATOR += adjustments[by_slowdown_layer_time[j]].ACTION
            // Calculate the current adjusted elapsed_time_total over the non-finalized extruders.
            float        total;
            FORALL_UNPROCESSED(total, elapsed_time_total());
            float        slowdown_below_layer_time = float(config.slowdown_below_layer_time.get_at(elapsed_times[idx].extruder_id)) * 1.001f;
            if (total > slowdown_below_layer_time) {
                // The current total time is above the minimum threshold of the rest of the extruders, don't adjust anything.
            } else {
                // Adjust this and all the following (higher config.slowdown_below_layer_time) extruders.
                // Sum maximum slow down time as if everything was slowed down including the external perimeters.
                float max_time;
                FORALL_UNPROCESSED(max_time, maximum_time(true));
                if (max_time > slowdown_below_layer_time) {
                    // By slowing every possible movement, the layer time could be reached. Now decide
                    // whether the external perimeters shall be slowed down as well.
                    float max_time_nep;
                    FORALL_UNPROCESSED(max_time_nep, maximum_time(false));
                    if (max_time_nep > slowdown_below_layer_time) {
                        // It is sufficient to slow down the non-external perimeter moves to reach the target layer time.
                        // Slow down the non-external perimeters proportionally.
                        float non_adjustable_time;
                        FORALL_UNPROCESSED(non_adjustable_time, non_adjustable_time(false));
                        // The following step is a linear programming task due to the minimum movement speeds of the print moves.
                        // Run maximum 5 iterations until a good enough approximation is reached.
                        for (size_t iter = 0; iter < 5; ++ iter) {
							float factor = (slowdown_below_layer_time - non_adjustable_time) / (total - non_adjustable_time);
                            assert(factor > 1.f);
                            FORALL_UNPROCESSED(total, slow_down_proportional(factor, false));
                            if (total > 0.95f * slowdown_below_layer_time)
                                break;
                        }
                    } else {
                        // Slow down everything. First slow down the non-external perimeters to maximum.
                        FORALL_UNPROCESSED(total, slow_down_maximum(false));
                        // Slow down the external perimeters proportionally.
                        float non_adjustable_time;
                        FORALL_UNPROCESSED(non_adjustable_time, non_adjustable_time(true));
                        for (size_t iter = 0; iter < 5; ++ iter) {
							float factor = (slowdown_below_layer_time - non_adjustable_time) / (total - non_adjustable_time);
                            assert(factor > 1.f);
                            FORALL_UNPROCESSED(total, slow_down_proportional(factor, true));
                            if (total > 0.95f * slowdown_below_layer_time)
                                break;
                        }
                    }
                } else {
                    // Slow down to maximum possible.
                    FORALL_UNPROCESSED(total, slow_down_maximum(true));
                }
            }
            #undef FORALL_UNPROCESSED
            // Sum the final elapsed time for all extruders up to i_by_slowdown_layer_time.
            if (i_by_slowdown_layer_time + 1 == by_slowdown_layer_time.size())
                // Optimization for single extruder prints.
                elapsed_time_total0 = total;
            else
                elapsed_time_total0 += adjustments[idx].elapsed_time_total();
        }
        elapsed_time_total = elapsed_time_total0;
    }

    // Transform the G-code.
    // First sort the adjustment lines by their position in the source G-code.
    std::vector<const Adjustment::Line*> lines;
    {
        size_t n_lines = 0;
        for (const Adjustment &adj : adjustments)
            n_lines += adj.lines.size();
        lines.reserve(n_lines);
        for (const Adjustment &adj : adjustments)
            for (const Adjustment::Line &line : adj.lines)
                lines.emplace_back(&line);
        std::sort(lines.begin(), lines.end(), [](const Adjustment::Line *ln1, const Adjustment::Line *ln2) { return ln1->line_start < ln2->line_start; } );
    }
    // Second generate the adjusted G-code.
    std::string new_gcode;
    new_gcode.reserve(gcode.size() * 2);
    int  fan_speed          = -1;
    bool bridge_fan_control = false;
    int  bridge_fan_speed   = 0;
    auto change_extruder_set_fan = [ this, layer_id, elapsed_time_total, &new_gcode, &fan_speed, &bridge_fan_control, &bridge_fan_speed ]() {
        const FullPrintConfig &config = m_gcodegen.config();
        int min_fan_speed = EXTRUDER_CONFIG(min_fan_speed);
        int fan_speed_new = EXTRUDER_CONFIG(fan_always_on) ? min_fan_speed : 0;
        if (layer_id >= EXTRUDER_CONFIG(disable_fan_first_layers)) {
            int   max_fan_speed             = EXTRUDER_CONFIG(max_fan_speed);
            float slowdown_below_layer_time = float(EXTRUDER_CONFIG(slowdown_below_layer_time));
            float fan_below_layer_time      = float(EXTRUDER_CONFIG(fan_below_layer_time));
            if (EXTRUDER_CONFIG(cooling)) {
                if (elapsed_time_total < slowdown_below_layer_time) {
                    // Layer time very short. Enable the fan to a full throttle.
                    fan_speed_new = max_fan_speed;
                } else if (elapsed_time_total < fan_below_layer_time) {
                    // Layer time quite short. Enable the fan proportionally according to the current layer time.
                    assert(elapsed_time_total >= slowdown_below_layer_time);
                    double t = (elapsed_time_total - slowdown_below_layer_time) / (fan_below_layer_time - slowdown_below_layer_time);
                    fan_speed_new = int(floor(t * min_fan_speed + (1. - t) * max_fan_speed) + 0.5);
                }
            }
            bridge_fan_speed   = EXTRUDER_CONFIG(bridge_fan_speed);
            bridge_fan_control = bridge_fan_speed > fan_speed_new;
        } else {
            bridge_fan_control = false;
            bridge_fan_speed   = 0;
        }
        if (fan_speed_new != fan_speed) {
            fan_speed = fan_speed_new;
            new_gcode += m_gcodegen.writer().set_fan(fan_speed);
        }
    };
	change_extruder_set_fan();

    size_t pos = 0;
    for (const Adjustment::Line *line : lines) {
        if (line->line_start > pos)
            new_gcode.append(gcode.c_str() + pos, line->line_start - pos);
        if (line->type & Adjustment::Line::TYPE_SET_TOOL) {
            unsigned int new_extruder = (unsigned int)atoi(gcode.c_str() + line->line_start + toolchange_prefix.size());
            if (new_extruder != m_current_extruder) {
                m_current_extruder = new_extruder;
                change_extruder_set_fan();
            }
        } else if (line->type & Adjustment::Line::TYPE_BRIDGE_FAN_START) {
            if (bridge_fan_control)
                new_gcode += m_gcodegen.writer().set_fan(bridge_fan_speed, true) + "\n";
        } else if (line->type & Adjustment::Line::TYPE_BRIDGE_FAN_END) {
            if (bridge_fan_control)
                new_gcode += m_gcodegen.writer().set_fan(fan_speed, true) + "\n";
        } else if (line->type & Adjustment::Line::TYPE_EXTRUDE_END) {
            // Just remove this comment.
        } else if (line->type & (Adjustment::Line::TYPE_ADJUSTABLE | Adjustment::Line::TYPE_EXTERNAL_PERIMETER | Adjustment::Line::TYPE_WIPE)) {
            // Start of the comment. The line type indicates there must be some comment present.
            const char *end = strchr(gcode.c_str() + line->line_start, ';');
            if (line->slowdown) {
                // Replace the feedrate.
                const char *pos = strstr(gcode.c_str() + line->line_start + 2, " F") + 2;
                new_gcode.append(gcode.c_str() + line->line_start, pos - gcode.c_str() - line->line_start);
                char buf[64];
                sprintf(buf, "%d", int(floor(60. * (line->length / line->time) + 0.5)));
                new_gcode += buf;
                // Skip the non-whitespaces up to the comment.
                for (; *pos != ' ' && *pos != ';'; ++ pos);
                // Append the rest of the line without the comment.
                if (pos < end)
                    new_gcode.append(pos, end - pos);
            } else {
                // Append the line without the comment.
                new_gcode.append(gcode.c_str() + line->line_start, end - gcode.c_str() - line->line_start);
            }
            // Process the comments, remove ";_EXTRUDE_SET_SPEED", ";_EXTERNAL_PERIMETER", ";_WIPE"
            std::string comment(end, gcode.c_str() + line->line_end);
            boost::replace_all(comment, ";_EXTRUDE_SET_SPEED", "");
            if (line->type & Adjustment::Line::TYPE_EXTERNAL_PERIMETER)
                boost::replace_all(comment, ";_EXTERNAL_PERIMETER", "");
            if (line->type & Adjustment::Line::TYPE_WIPE)
                boost::replace_all(comment, ";_WIPE", "");
            new_gcode += comment;
        } else {
			new_gcode.append(gcode.c_str() + line->line_start, line->line_end - line->line_start);
        }
        pos = line->line_end;
    }
    if (pos < gcode.size())
        new_gcode.append(gcode.c_str() + pos, gcode.size() - pos);

    m_gcodegen.writer().reset_elapsed_times();
    return new_gcode;
}

} // namespace Slic3r