#!/usr/bin/perl

use strict;
use warnings;
use POSIX qw(strftime);
use utf8;
use open qw(:std :utf8);
use Encode qw(encode decode);

my $p_flag = 0;

my $date = time;
my $data_d = '/home/ghz/solar_power_wx/data';

my $out_dat_f = "$data_d/2-3_day.power";
my $out_dat_f_t = "$out_dat_f.tmp";

unlink $out_dat_f or printf "could not delete $out_dat_f\n";
if (-e $out_dat_f_t) {
	unlink $out_dat_f_t or printf "could not delete $out_dat_f_t\n";
}

open(OUT, ">>", $out_dat_f) or die "omg! can't open output file: $out_dat_f";
open(OUT_t, ">>", $out_dat_f_t) or die "omg! can't open output file: $out_dat_f_t";

my $date_pat = strftime "%Y%m%d%H", localtime($date - (2 * 86400));

for (my $nday = 2; $nday >= 0; $nday--) {
	my $date_it = $date - ($nday * 86400);

	my $datey = strftime "%Y", localtime($date_it);
	my $tdatey = strftime "%Y%m%d", localtime($date_it);

	my $in_dat_f = "$data_d/$datey/solar_power.$tdatey";

	if (-e $in_dat_f) {
		open(IN, "<", $in_dat_f) or die "omg! can't open input file: $in_dat_f";

		while (<IN>) {
			$p_flag = 1 if(/^$date_pat/);
			printf OUT;
			printf OUT_t if($p_flag);
		}
		close(IN);
	}
}
close(OUT);
close(OUT_t);

if (-e $out_dat_f_t && -s $out_dat_f_t >= 100000) {
	rename $out_dat_f_t, $out_dat_f; 
} elsif (-e $out_dat_f_t) {
	unlink $out_dat_f_t or printf "could not delete $out_dat_f_t\n";
}