/*
 *                 GRAPH, Version 1.00 - 4 August 1989
 *
 *            Copyright 1989, David Gay. All Rights Reserved.
 *            This software is freely redistrubatable.
 */

#include <exec/types.h>
#include <intuition/intuition.h>
#include <graphics/text.h>
#include <math.h>
#include <string.h>

#include "object.h"
#include "object/function.h"
#include "file.h"
#include "graph.h"
#include "uio.h"
#include "coords.h"
#include "list.h"
#include "grph.h"
#include "user/eval.h"
#include "user/gadgets.h"
#include "tracker.h"

#include <proto/exec.h>
#include <proto/intuition.h>
#include <proto/graphics.h>

struct x_y {
    struct function f;
    char x[EXPRLEN], y[EXPRLEN];
    value x_t, y_t, dx, dy;
};

struct point_x_y {
    point p;
    double t;
};

typedef struct point_x_y point_x_y;

/*-------------------------------------------------------------------------*/
/*                        x_y class implementation                         */
/*-------------------------------------------------------------------------*/

/* Is the function displayable ? */
static int x_y_ok(const struct x_y *this)
{
    return this->f.min != NOVAL && this->f.max != NOVAL &&
           this->f.min < this->f.max &&
           (this->f.steps == INOVAL || this->f.steps >= 3);
}

/* Free resources */
static void destroy_x_y(struct x_y *this)
{
    free_var_list(&this->f.used);
    if (this->f.calc) free_list(&this->f.pts, this->f.sizept);
    this->f.calc = FALSE;
    if (this->x_t) free_expr(this->x_t);
    if (this->dx) free_expr(this->dx);
    if (this->y_t) free_expr(this->y_t);
    if (this->dy) free_expr(this->dy);
    this->dx = this->dy = this->x_t = this->y_t = NULL;
}

/* Init dependant parts of function */
static int create_x_y(struct x_y *this)
{
    this->f.calc = FALSE;
    this->f.var.name = this->f.vname;
    this->x_t = compile(this->x);
    if (eval_error != 0)
    {
        message(this->f.o.g, "Compilation error in x(t):", eval_messages[eval_e
rror], (char *)NULL);
        return FALSE;
    }
    this->dx = differentiate(this->x_t, this->f.vname);
    if (eval_error != NOT_DIFFERENTIABLE && eval_error != 0)
    {
        message(this->f.o.g, "Differentiation error (x):", eval_messages[eval_e
rror], (char *)NULL);
        return FALSE;
    }
    this->y_t = compile(this->y);
    if (eval_error != 0)
    {
        message(this->f.o.g, "Compilation error in y(t):", eval_messages[eval_e
rror], (char *)NULL);
        return FALSE;
    }
    this->dy = differentiate(this->y_t, this->f.vname);
    if (eval_error != NOT_DIFFERENTIABLE && eval_error != 0)
    {
        message(this->f.o.g, "Differentiation error(y):", eval_messages[eval_er
ror], (char *)NULL);
        return FALSE;
    }
    if (!make_var_list(this->x_t, &this->f.used) || !make_var_list(this->y_t, &
this->f.used))
        init_var_list(&this->f.used);
    return TRUE;
}

/* Allow user to define function */
static int edit_x_y(struct x_y *this, struct Region **ref)
{
    struct Requester *req;
    struct Memory *m;
    struct Gadget *gl = NULL, *sd, *nd;
    char from[NBLEN], to[NBLEN], steps[INTLEN], x[EXPRLEN], y[EXPRLEN], tname[V
ARLEN], colour[INTLEN];
    int ret = FALSE;

    *ref = NULL;

    /* Create requester */
    double2str(from, this->f.min);
    double2str(to, this->f.max);
    int2str(steps, this->f.steps);
    int2str(colour, this->f.colour);
    strcpy(x, this->x);
    strcpy(y, this->y);
    strcpy(tname, this->f.vname);

    if ((m = NewMemory()) &&
        (req = InitReq(50, 20, 255, 165, m)) &&
        SetReqBorder(req, 1, m) &&
        AddIntuiText(&req->ReqText, "Function", 95, 6, m) &&
        AddText(&gl, 0, "x(", FALSE, tname, VARLEN, TRUE, 0, RELVERIFY, 25, 20,
 24, 10, TRUE, m) &&
        AddText(&gl, 0, ")=", FALSE, x, EXPRLEN, TRUE, 0, RELVERIFY, 81, 20, 16
0, 10, TRUE, m) &&
        AddText(&gl, 0, "y(   )=", FALSE, y, EXPRLEN, TRUE, 0, RELVERIFY, 81, 4
0, 160, 10, TRUE, m) &&
        AddText(&gl, 0, "from ", FALSE, from, NBLEN, TRUE, 0, RELVERIFY, 49, 60
, 80, 10, TRUE, m) &&
        AddText(&gl, 0, "to ", FALSE, to, NBLEN, TRUE, 0, RELVERIFY, 167, 60, 8
0, 10, TRUE, m) &&
        AddText(&gl, 0, "steps ", FALSE, steps, INTLEN, TRUE, 0, RELVERIFY, 57,
 80, 32, 10, TRUE, m) &&
        AddText(&gl, 0, "colour ", FALSE, colour, INTLEN, TRUE, 0, RELVERIFY, 1
56, 80, 32, 10, TRUE, m) &&
        (sd = AddOption(&gl, 0, "Show discontinuities", TRUE, this->f.showdisc
* SELECTED, 0, 9, 100, 10, 10, m)) &&
        (nd = AddOption(&gl, 0, "Allow flat discontinuities", TRUE, this->f.nic
edisc * SELECTED, 0, 9, 120, 10, 10, m)) &&
        AddBox(&gl, TRUE, "Ok", 0, RELVERIFY | ENDGADGET, 40, 140, 65, 15, FALS
E, m) &&
        AddBox(&gl, FALSE, "Cancel", 0, RELVERIFY | ENDGADGET, 145, 140, 65, 15
, FALSE, m))
    {
        SetReqGadgets(req, gl);
        if (ret = DoRequest(req, this->f.o.g, std_ghandler))
        {
            *ref = full_refresh(this->f.o.g);

            /* Extract info */
            this->f.min = str2double(from);
            this->f.max = str2double(to);
            this->f.steps = str2int(steps);
            if ((this->f.colour = str2int(colour)) == INOVAL) this->f.colour =
1;
            this->f.showdisc = (sd->Flags & SELECTED) != 0;
            this->f.nicedisc = (nd->Flags & SELECTED) != 0;
            strcpy(this->x, x);
            strcpy(this->y, y);
            strcpy(this->f.vname, tname);

            /* Create function */
            destroy_x_y(this);
            if (this->f.o.ok = x_y_ok(this)) this->f.o.ok = create_x_y(this);
        }
    }
    Free(m);

    return ret;
}

/* Calculate points of function */
static int calc_x_y(struct x_y *this, int allow_mes)
{
    double t;
    int i;
    struct graph *const g = this->f.o.g;
    double const tmin = this->f.min;
    double const tmax = this->f.max;
    int const steps = this->f.steps == INOVAL ? DEFSTEPS : this->f.steps;
    double const step = (tmax - tmin) / (steps - 1);
    static char func[FNAMELEN + 30];

    strcpy(func, "Can't calculate points for ");
    strcat(func, this->f.o.name);
    strcat(func, ":");

    new_list(&this->f.pts);

    if (!create_quick(&this->f.var))
    {
        if (allow_mes) message(g, func, "Couldn't create variable", (char *)NUL
L);
        else alert(g->io.win, func, "Couldn't create variable");
        return FALSE;
    }

    /* Calculate steps points, spread evenly from min to max */
    for (i = 0, t = tmin; i < steps; i++, t += step)
    {
        point_x_y *pt = alloc_node(this->f.sizept);

        if (!pt)
        { /* No mem */
            free_list(&this->f.pts, this->f.sizept);
            free_quick(&this->f.var);
            if (allow_mes) message(g, func, "No memory", (char *)NULL);
            else alert(g->io.win, func, "No memory");
            return FALSE;
        }
        add_tail(&this->f.pts, pt);

        set_quick(&this->f.var, t);
        pt->t = t;

        pt->p.x = quick_eval(this->x_t);
        pt->p.state = (eval_error == 0) ? EXISTS : 0;
        if (pt->p.state == EXISTS)
        {
            pt->p.y = quick_eval(this->y_t);
            pt->p.state = (eval_error == 0) ? EXISTS : 0;
        }
    }
    free_quick(&this->f.var);
    return TRUE;
}

/* Try to improve look of function by adding points. If fails, decides that
   there is a discontinuity */
/* see f_of_x.c for details */
static int improve_x_y(struct x_y *this)
{
    struct graph *const g = this->f.o.g;
    point_x_y *pt, *next;
    int ok = FALSE, iter, abort = FALSE;
    double flatx = FLAT * (g->a.y.max - g->a.y.min) / g->io.win->Height;
    double flaty = FLAT * (g->a.x.max - g->a.x.min) / g->io.win->Width;
    char msg[FNAMELEN + 30];
    char pass[20];
    struct Requester *req;
    struct Region *full = NULL;

    /* Flat has no meaning when graph incorrect */
    if (!this->f.o.g->ok) flatx = flaty = 0.0;

    if (!this->f.calc)
    {
        strcpy(msg, this->f.o.name);
        strcpy(msg, "not calculated!");
        message(g, msg, (char *)NULL);
        return NULL;
    }
    if (!this->dx || !this->dy)
    {
        strcpy(msg, this->f.o.name);
        strcat(msg, " wasn't differentiable");
        message(g, msg, (char *)NULL);
        return NULL;
    }
    if (!create_quick(&this->f.var))
    {
        message(g, "Couldn't create variable", (char *)NULL);
        return NULL;
    }

    if (!(req = abort_request(g, "Improve: Pass 1")))
        message(g, "No Memory !", (char *)NULL);
    else
    {
        full = full_refresh(this->f.o.g);

        for (iter = 1; iter <= MAXITER && !ok && !abort; iter++)
        {
            sprintf(pass, "Improve: Pass %d", iter);
            set_abort_msg(req, pass);
            ok = TRUE;

            for (pt = first(&this->f.pts); succ(next = succ(pt)); pt = next)
            {
                if ((pt->p.state & (EXISTS | OK)) == EXISTS) /* Only exists */
                {
                    double dx, dy;

                    pt->p.state |= OK;
                    pt->p.state &= ~DISC;

                    set_quick(&this->f.var, pt->t);
                    dx = quick_eval(this->dx);
                    if (eval_error == 0)
                    {
                        dy = quick_eval(this->dy);
                        if (eval_error == 0)
                        {
                            double ecartx = next->p.x - pt->p.x;
                            double errorx = fabs(ecartx - (next->t - pt->t) * d
x);
                            double ecarty = next->p.y - pt->p.y;
                            double errory = fabs(ecarty - (next->t - pt->t) * d
y);

                            /* Check both axes */
                            if ((errorx > fabs(ecartx) * MAXERROR && (!this->f.
nicedisc || errorx > flatx)) ||
                                (errory > fabs(ecarty) * MAXERROR && (!this->f.
nicedisc || errory > flaty)))
                            {
                                pt->p.state &= ~OK;
                                ok = FALSE;

                                if (iter == MAXITER) pt->p.state |= DISC;
                                else /* cut interval in 2 */
                                {
                                    point_x_y *newpt = alloc_node(this->f.sizep
t);

                                    if (!newpt)
                                    {
                                        nomem(g->io.win);
                                        abort = TRUE;
                                        break;
                                    }

                                    newpt->t = (pt->t + next->t) / 2;
                                    set_quick(&this->f.var, newpt->t);
                                    newpt->p.x = quick_eval(this->x_t);
                                    newpt->p.state = (eval_error == 0) ? EXISTS
 : 0;
                                    if (newpt->p.state == EXISTS)
                                    {
                                        newpt->p.y = quick_eval(this->y_t);
                                        newpt->p.state = (eval_error == 0) ? EX
ISTS : 0;
                                    }
                                    insert(&this->f.pts, newpt, pt);
                                }
                            }
                        }
                    }
                }
            }
        }
        end_abort_request(req);
    }
    free_quick(&this->f.var);
    return full;
}

/* String representation of function */
static char *f2str_x_y(struct x_y *this, char *buf, int maxlen)
{
    buf[maxlen - 1] = '\0';
    strncpy(buf, this->f.o.name, maxlen - 1);
    strncat(buf, ": x(", maxlen - strlen(buf) - 1);
    strncat(buf, this->f.vname, maxlen - strlen(buf) - 1);
    strncat(buf, ")=", maxlen - strlen(buf) - 1);
    strncat(buf, this->x, maxlen - strlen(buf) - 1);
    strncat(buf, ", y(", maxlen - strlen(buf) - 1);
    strncat(buf, this->f.vname, maxlen - strlen(buf) - 1);
    strncat(buf, ")=", maxlen - strlen(buf) - 1);
    strncat(buf, this->y, maxlen - strlen(buf) - 1);

    return buf;
}

/* Save local data to file */
static int save_x_y(struct x_y *this, FILE *f)
{
    short tag = X_Y_TAG;
    short end = X_Y_END;

    return WRITE(f, tag) &&
           WRITE(f, this->x) &&
           WRITE(f, this->y) &&
           WRITE(f, end);
}

/* free function */
static struct Region *delete_x_y(struct x_y *this)
{
    struct Region *full = full_refresh(this->f.o.g);

    destroy_x_y(this);
    FreeMem(this, sizeof(struct x_y));

    return full;
}

/* Create a new function */
struct x_y *new_x_y(struct graph *g, char *name)
{
    struct x_y *this = AllocMem(sizeof(struct x_y), MEMF_CLEAR);

    if (this)
    {
        /* Standard init */
        init_function(&this->f, g, name);
        /* Local methods */
        this->f.o.delete = (void *)delete_x_y;
        this->f.o.edit = (void *)edit_x_y;
        this->f.o.improve = (void *)improve_x_y;
        this->f.o.f2str = (void *)f2str_x_y;
        this->f.calcf = (void *)calc_x_y;
        this->f.save = (void *)save_x_y;
        this->f.sizept = sizeof(point_x_y);
        return this;
    }
    message(g, "Couldn't create function:", "No memory", (char *)NULL);
    return NULL;
}

/* load from file */
struct x_y *load_x_y(struct graph *g, FILE *f)
{
    struct x_y *this = new_x_y(g, "");

    if (this)
    {
        short end;

        /* Read local data */
        if (READ(f, this->x) &&
            READ(f, this->y) &&
            READ(f, end) &&
            end == X_Y_END)
        {
            load_rest(&this->f, f); /* Read standard data */
            if (this->f.o.ok = x_y_ok(this)) this->f.o.ok = create_x_y(this);

            return this;
        }
        delete_x_y(this);
    }
    return NULL;
}