#include "water.h"
#include <string.h>
#include <ctype.h>

PetscErrorCode PumpHeadCurveResidual(SNES snes, Vec X, Vec F, void *ctx)
{
  const PetscScalar *x;
  PetscScalar       *f;
  Pump              *pump = (Pump *)ctx;
  PetscScalar       *head = pump->headcurve.head, *flow = pump->headcurve.flow;
  PetscInt           i;

  PetscFunctionBegin;
  PetscCall(VecGetArrayRead(X, &x));
  PetscCall(VecGetArray(F, &f));

  f[0] = f[1] = f[2] = 0;
  for (i = 0; i < pump->headcurve.npt; i++) {
    f[0] += x[0] - x[1] * PetscPowScalar(flow[i], x[2]) - head[i];                                                          /* Partial w.r.t x[0] */
    f[1] += (x[0] - x[1] * PetscPowScalar(flow[i], x[2]) - head[i]) * -1 * PetscPowScalar(flow[i], x[2]);                   /* Partial w.r.t x[1] */
    f[2] += (x[0] - x[1] * PetscPowScalar(flow[i], x[2]) - head[i]) * -1 * x[1] * x[2] * PetscPowScalar(flow[i], x[2] - 1); /* Partial w.r.t x[2] */
  }

  PetscCall(VecRestoreArrayRead(X, &x));
  PetscCall(VecRestoreArray(F, &f));
  PetscFunctionReturn(PETSC_SUCCESS);
}

PetscErrorCode SetPumpHeadCurveParams(Pump *pump)
{
  SNES                snes;
  Vec                 X, F;
  PetscScalar        *head, *flow, *x;
  SNESConvergedReason reason;

  PetscFunctionBegin;
  head = pump->headcurve.head;
  flow = pump->headcurve.flow;
  if (pump->headcurve.npt == 1) {
    /* Single point head curve, set the other two data points */
    flow[1] = 0;
    head[1] = 1.33 * head[0]; /* 133% of design head -- From EPANET manual */
    flow[2] = 2 * flow[0];    /* 200% of design flow -- From EPANET manual */
    head[2] = 0;
    pump->headcurve.npt += 2;
  }

  PetscCall(SNESCreate(PETSC_COMM_SELF, &snes));

  PetscCall(VecCreate(PETSC_COMM_SELF, &X));
  PetscCall(VecSetSizes(X, 3, 3));
  PetscCall(VecSetFromOptions(X));
  PetscCall(VecDuplicate(X, &F));

  PetscCall(SNESSetFunction(snes, F, PumpHeadCurveResidual, (void *)pump));
  PetscCall(SNESSetJacobian(snes, NULL, NULL, SNESComputeJacobianDefault, NULL));
  PetscCall(SNESSetFromOptions(snes));

  PetscCall(VecGetArray(X, &x));
  x[0] = head[1];
  x[1] = 10;
  x[2] = 3;
  PetscCall(VecRestoreArray(X, &x));

  PetscCall(SNESSolve(snes, NULL, X));

  PetscCall(SNESGetConvergedReason(snes, &reason));
  PetscCheck(reason >= 0, PETSC_COMM_SELF, PETSC_ERR_CONV_FAILED, "Pump head curve did not converge");

  PetscCall(VecGetArray(X, &x));
  pump->h0 = x[0];
  pump->r  = x[1];
  pump->n  = x[2];
  PetscCall(VecRestoreArray(X, &x));

  PetscCall(VecDestroy(&X));
  PetscCall(VecDestroy(&F));
  PetscCall(SNESDestroy(&snes));
  PetscFunctionReturn(PETSC_SUCCESS);
}

int LineStartsWith(const char *a, const char *b)
{
  if (strncmp(a, b, strlen(b)) == 0) return 1;
  return 0;
}

int CheckDataSegmentEnd(const char *line)
{
  if (LineStartsWith(line, "[JUNCTIONS]") || LineStartsWith(line, "[RESERVOIRS]") || LineStartsWith(line, "[TANKS]") || LineStartsWith(line, "[PIPES]") || LineStartsWith(line, "[PUMPS]") || LineStartsWith(line, "[CURVES]") || LineStartsWith(line, "[VALVES]") || LineStartsWith(line, "[PATTERNS]") || LineStartsWith(line, "[VALVES]") || LineStartsWith(line, "[QUALITY]") || LineStartsWith(line, "\n") || LineStartsWith(line, "\r\n")) {
    return 1;
  }
  return 0;
}

/* Gets the file pointer positiion for the start of the data segment and the
   number of data segments (lines) read
*/
PetscErrorCode GetDataSegment(FILE *fp, char *line, fpos_t *data_segment_start_pos, PetscInt *ndatalines)
{
  PetscInt data_segment_end;
  PetscInt nlines = 0;

  PetscFunctionBegin;
  data_segment_end = 0;
  fgetpos(fp, data_segment_start_pos);
  PetscCheck(fgets(line, MAXLINE, fp), PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Cannot read data segment from file");
  while (LineStartsWith(line, ";")) {
    fgetpos(fp, data_segment_start_pos);
    PetscCheck(fgets(line, MAXLINE, fp), PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Cannot read data segment from file");
  }
  while (!data_segment_end) {
    PetscCheck(fgets(line, MAXLINE, fp), PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Cannot read data segment from file");
    nlines++;
    data_segment_end = CheckDataSegmentEnd(line);
  }
  *ndatalines = nlines;
  PetscFunctionReturn(PETSC_SUCCESS);
}

PetscErrorCode WaterReadData(WATERDATA *water, char *filename)
{
  FILE        *fp = NULL;
  VERTEX_Water vert;
  EDGE_Water   edge;
  fpos_t       junc_start_pos, res_start_pos, tank_start_pos, pipe_start_pos, pump_start_pos;
  fpos_t       curve_start_pos, title_start_pos;
  char         line[MAXLINE];
  PetscInt     i, j, nv = 0, ne = 0, ncurve = 0, ntitle = 0, nlines, ndata, curve_id;
  Junction    *junction  = NULL;
  Reservoir   *reservoir = NULL;
  Tank        *tank      = NULL;
  Pipe        *pipe      = NULL;
  Pump        *pump      = NULL;
  PetscScalar  curve_x, curve_y;
  double       v1, v2, v3, v4, v5, v6;

  PetscFunctionBegin;
  water->nvertex = water->nedge = 0;
  fp                            = fopen(filename, "rb");
  /* Check for valid file */
  PetscCheck(fp, PETSC_COMM_SELF, PETSC_ERR_FILE_OPEN, "Can't open EPANET data file %s", filename);

  /* Read file and get line numbers for different data segments */
  while (fgets(line, MAXLINE, fp)) {
    if (strstr(line, "[TITLE]")) PetscCall(GetDataSegment(fp, line, &title_start_pos, &ntitle));

    if (strstr(line, "[JUNCTIONS]")) {
      PetscCall(GetDataSegment(fp, line, &junc_start_pos, &nlines));
      water->nvertex += nlines;
      water->njunction = nlines;
    }

    if (strstr(line, "[RESERVOIRS]")) {
      PetscCall(GetDataSegment(fp, line, &res_start_pos, &nlines));
      water->nvertex += nlines;
      water->nreservoir = nlines;
    }

    if (strstr(line, "[TANKS]")) {
      PetscCall(GetDataSegment(fp, line, &tank_start_pos, &nlines));
      water->nvertex += nlines;
      water->ntank = nlines;
    }

    if (strstr(line, "[PIPES]")) {
      PetscCall(GetDataSegment(fp, line, &pipe_start_pos, &nlines));
      water->nedge += nlines;
      water->npipe = nlines;
    }

    if (strstr(line, "[PUMPS]")) {
      PetscCall(GetDataSegment(fp, line, &pump_start_pos, &nlines));
      water->nedge += nlines;
      water->npump = nlines;
    }

    if (strstr(line, "[CURVES]")) PetscCall(GetDataSegment(fp, line, &curve_start_pos, &ncurve));
  }

  /* Allocate vertex and edge data structs */
  PetscCall(PetscCalloc1(water->nvertex, &water->vertex));
  PetscCall(PetscCalloc1(water->nedge, &water->edge));
  vert = water->vertex;
  edge = water->edge;

  /* Junctions */
  fsetpos(fp, &junc_start_pos);
  for (i = 0; i < water->njunction; i++) {
    int id = 0, pattern = 0;
    PetscCheck(fgets(line, MAXLINE, fp), PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Cannot read junction from file");
    vert[nv].type = VERTEX_TYPE_JUNCTION;
    junction      = &vert[nv].junc;
    ndata         = sscanf(line, "%d %lf %lf %d", &id, &v1, &v2, &pattern);
    PetscCheck(ndata >= 3, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read junction data");
    vert[nv].id          = id;
    junction->dempattern = pattern;
    junction->elev       = (PetscScalar)v1;
    junction->demand     = (PetscScalar)v2;
    junction->demand *= GPM_CFS;
    junction->id = vert[nv].id;
    nv++;
  }

  /* Reservoirs */
  fsetpos(fp, &res_start_pos);
  for (i = 0; i < water->nreservoir; i++) {
    int id = 0, pattern = 0;
    PetscCheck(fgets(line, MAXLINE, fp), PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Cannot read reservoir from file");
    vert[nv].type = VERTEX_TYPE_RESERVOIR;
    reservoir     = &vert[nv].res;
    ndata         = sscanf(line, "%d %lf %d", &id, &v1, &pattern);
    PetscCheck(ndata >= 2, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read reservoir data");
    vert[nv].id            = id;
    reservoir->headpattern = pattern;
    reservoir->head        = (PetscScalar)v1;
    reservoir->id          = vert[nv].id;
    nv++;
  }

  /* Tanks */
  fsetpos(fp, &tank_start_pos);
  for (i = 0; i < water->ntank; i++) {
    int id = 0, curve = 0;
    PetscCheck(fgets(line, MAXLINE, fp), PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Cannot read data tank from file");
    vert[nv].type = VERTEX_TYPE_TANK;
    tank          = &vert[nv].tank;
    ndata         = sscanf(line, "%d %lf %lf %lf %lf %lf %lf %d", &id, &v1, &v2, &v3, &v4, &v5, &v6, &curve);
    PetscCheck(ndata >= 7, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read tank data");
    vert[nv].id       = id;
    tank->volumecurve = curve;
    tank->elev        = (PetscScalar)v1;
    tank->initlvl     = (PetscScalar)v2;
    tank->minlvl      = (PetscScalar)v3;
    tank->maxlvl      = (PetscScalar)v4;
    tank->diam        = (PetscScalar)v5;
    tank->minvolume   = (PetscScalar)v6;
    tank->id          = vert[nv].id;
    nv++;
  }

  /* Pipes */
  fsetpos(fp, &pipe_start_pos);
  for (i = 0; i < water->npipe; i++) {
    int id = 0, node1 = 0, node2 = 0;
    PetscCheck(fgets(line, MAXLINE, fp), PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Cannot read data pipe from file");
    edge[ne].type   = EDGE_TYPE_PIPE;
    pipe            = &edge[ne].pipe;
    ndata           = sscanf(line, "%d %d %d %lf %lf %lf %lf %s", &id, &node1, &node2, &v1, &v2, &v3, &v4, pipe->stat);
    pipe->id        = id;
    pipe->node1     = node1;
    pipe->node2     = node2;
    pipe->length    = (PetscScalar)v1;
    pipe->diam      = (PetscScalar)v2;
    pipe->roughness = (PetscScalar)v3;
    pipe->minorloss = (PetscScalar)v4;
    edge[ne].id     = pipe->id;
    if (strcmp(pipe->stat, "OPEN") == 0) pipe->status = PIPE_STATUS_OPEN;
    if (ndata < 8) {
      strcpy(pipe->stat, "OPEN"); /* default OPEN */
      pipe->status = PIPE_STATUS_OPEN;
    }
    if (ndata < 7) pipe->minorloss = 0.;
    pipe->n = 1.85;
    pipe->k = 4.72 * pipe->length / (PetscPowScalar(pipe->roughness, pipe->n) * PetscPowScalar(0.0833333 * pipe->diam, 4.87));
    ne++;
  }

  /* Pumps */
  fsetpos(fp, &pump_start_pos);
  for (i = 0; i < water->npump; i++) {
    int id = 0, node1 = 0, node2 = 0, paramid = 0;
    PetscCheck(fgets(line, MAXLINE, fp), PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Cannot read data pump from file");
    edge[ne].type = EDGE_TYPE_PUMP;
    pump          = &edge[ne].pump;
    ndata         = sscanf(line, "%d %d %d %s %d", &id, &node1, &node2, pump->param, &paramid);
    PetscCheck(ndata == 5, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read pump data");
    pump->id      = id;
    pump->node1   = node1;
    pump->node2   = node2;
    pump->paramid = paramid;
    edge[ne].id   = pump->id;
    ne++;
  }

  /* Curves */
  fsetpos(fp, &curve_start_pos);
  for (i = 0; i < ncurve; i++) {
    int icurve_id = 0;
    PetscCheck(fgets(line, MAXLINE, fp), PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Cannot read data curve from file");
    ndata = sscanf(line, "%d %lf %lf", &icurve_id, &v1, &v2);
    PetscCheck(ndata == 3, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read curve data");
    curve_id = icurve_id;
    curve_x  = (PetscScalar)v1;
    curve_y  = (PetscScalar)v2;
    /* Check for pump with the curve_id */
    for (j = water->npipe; j < water->npipe + water->npump; j++) {
      if (water->edge[j].pump.paramid == curve_id) {
        PetscCheck(pump->headcurve.npt != 3, PETSC_COMM_SELF, PETSC_ERR_SUP, "Pump %" PetscInt_FMT " [%" PetscInt_FMT " --> %" PetscInt_FMT "]: No support for more than 3-pt head-flow curve", pump->id, pump->node1, pump->node2);
        pump                                      = &water->edge[j].pump;
        pump->headcurve.flow[pump->headcurve.npt] = curve_x * GPM_CFS;
        pump->headcurve.head[pump->headcurve.npt] = curve_y;
        pump->headcurve.npt++;
        break;
      }
    }
  }

  fclose(fp);

  /* Get pump curve parameters */
  for (j = water->npipe; j < water->npipe + water->npump; j++) {
    pump = &water->edge[j].pump;
    if (strcmp(pump->param, "HEAD") == 0) {
      /* Head-flow curve */
      PetscCall(SetPumpHeadCurveParams(pump));
    }
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}