#! /usr/bin/gawk -f
# Last edited on 2014-03-18 01:43:40 by stolfilocal

BEGIN \
  { # Caller must define (with "-v") {DB,D0,D1,H0,H1,P0,P1,R}
    # Outputs "-line" commands from {D0-0.5} to {D1+0.5}.
    # The horiz position is {h(D) = H0 + H1*(d-DB)}.
    # The Huobi price is {pH(D) = P0 + P1*(d - DB)}.
    # The Bitstamp price is {pB(D) = pH(D)/R}.
    
    # Will plot from {D0-0.25} tp {D1+0.25}

    if (DB == "") { arg_error(("must define {DB}")); } # Reference day.
    if (D0 == "") { arg_error(("must define {D0}")); } # First day to plot.
    if (D1 == "") { arg_error(("must define {D1}")); } # Last day to plot.
    if (H0 == "") { arg_error(("must define {H0}")); } # H-coordinate of day {DB} (before "-hshift")
    if (H1 == "") { arg_error(("must define {H1}")); } # Increment in H-coordinate for 1 day.
    if (P0 == "") { arg_error(("must define {P0}")); } # Price at day {DB}.
    if (P1 == "") { arg_error(("must define {P1}")); } # Price increment per day.
    if (R == "")  { arg_error(("must define {R}")); }  # Currency conversion factor.
    
    for (k = 0; k < 2; k++)
      { d = (k == 0 ? D0 - 0.5 : D1 + 0.5); # Day number.
        h = int(H0 + H1*(d - DB) + 0.5);
        p = int((P0 + P1*(d - DB))/R + 0.5);
        if (k > 0) { printf "    -line  \"+\" %5d %5d  %5d %5d \\\n", h_ant, p_ant, h, p; }
        h_ant = h;
        p_ant = p;
      }
  }

#    echo 'd = 27.25; h = 2168 + 120*(d - 24); p = 9881.67 - 263*d; d; h; p; p/6.12'| bc -lq