package require http
 package require tdom
 package require tls
 package require vfs::zip

 http::register https 443 [list ::tls::socket]

 set tz "America/Los_Angeles"
 set datadir /usr/backup/power
 set user USER
 set pass PASSWORD

 if {$argc > 0} {
    set date [clock scan [lindex $argv 0]]
 } else {
    set date [clock seconds]
 }
 set month [clock format $date -format "%Y-%m"]

 proc cookies {t} {
    set cookies [list]

    foreach {k v} [http::meta $t] {
        if {[string tolower $k] eq "set-cookie"} {
            set v [split $v \;]
            set v [lindex $v 0]
            if {[lindex [split $v =] 1] == ""} continue
            lappend cookies $v
        }
    }
    return [list Cookie [join $cookies "; "]]
 }

 proc get_usage {month user pass} {
    set t [http::geturl "https://www.pge.com/eum/login" -query [http::formatQuery USER $user PASSWORD $pass pass_placeholder Password TARGET https://www.pge.com/myenergyweb/appmanager/pge/customer]]
 
    set cookies [cookies $t]
    http::cleanup $t

    # all this should need is EUMSessionID and SMSESSION
    set t [http::geturl "https://www.pge.com/affwebservices/public/saml2sso?SPID=sso.opower.com&RelayState=https%3A%2F%2Fpge.opower.com%2Fei%2Fapp%2FmyEnergyUse" -headers $cookies]
    set body [http::data $t]
    #parray $t
    http::cleanup $t

    set query [list]
    set html [dom parse -html $body]
    set root [$html documentElement]
    set action [[$root getElementsByTagName form] getAttribute action]
    foreach input [$root getElementsByTagName input] {
        if {[$input getAttribute type] != "hidden"} continue
        lappend query [$input getAttribute name] [$input getAttribute value]
    }
    
    
    set t [http::geturl $action -query [http::formatQuery {*}$query]]
    set body [http::data $t]
    http::cleanup $t

    set query [list]
    set html [dom parse -html $body]
    set root [$html documentElement]
    set action [[$root getElementsByTagName form] getAttribute action]
    foreach input [$root getElementsByTagName input] {
        if {[$input getAttribute type] != "hidden"} continue
        lappend query [$input getAttribute name] [$input getAttribute value]
    }
    
    set t [http::geturl $action -query [http::formatQuery {*}$query]]
    set cookies [cookies $t]
    http::cleanup $t

    set t [http::geturl "https://pge.opower.com/ei/app/myEnergyUse" -headers $cookies]
    #<a data-trigger-dialog="href" href="/ei/app/modules/customer/610138/bill_periods/export-dialog">Export your data</a>
    regexp {modules/customer/(\d+)/bill_periods} [http::data $t] -> customer
    http::cleanup $t

    set t [http::geturl "https://pge.opower.com/ei/app/modules/customer/$customer/energy/download?billing=false&bill=$month" -headers $cookies]

    if {[http::ncode $t] != 200} {
        return
    }

    set zip "/tmp/usage-$month.zip"
    set fh [open $zip w+]
    fconfigure $fh -translation binary
    puts -nonewline $fh [http::data $t]
    close $fh
    http::cleanup $t
    return $zip
 }

 proc write_csv {zip} {
    global datadir tz
    set mnt_file [vfs::zip::Mount $zip $zip]
    
    set in [open "$zip/DailyNaturalGasUsage.csv"]
    set csv [read $in]
    close $in
    #TYPE,DATE,USAGE,UNITS,NOTES
    #Natural gas usage,2011-10-27,1.03,therms,

    array set data {}
    foreach line [split $csv \n] {
        set line [split $line ,]
        if {[lindex $line 0] != "Natural gas usage"} continue
        set start [clock scan [lindex $line 1] -timezone $tz]
        set day [clock format $start -format "%Y-%m-%d"]
        lappend data($day) "$start,[lindex $line 2]"
    }
    foreach {day vals} [array get data] {
        set fn "$datadir/gas-$day.csv"
        if {[file exists $fn] && [file size $fn] != 0} continue
        set fh [open $fn w+]
        puts "writing $fn"
        puts $fh [join $vals \n]
        close $fh
    }


    set in [open "$zip/DailyElectricUsage.csv"]
    set csv [read $in]
    close $in
    #TYPE,DATE,START TIME,END TIME,USAGE,UNITS,NOTES
    #Electric usage,2011-09-28,00:00,00:59,0.16,kWh,
    
    unset -nocomplain data
    array set data {}
    foreach line [split $csv \n] {
        set line [split $line ,]
        if {[lindex $line 0] != "Electric usage"} continue
        set start [clock scan "[lindex $line 1] [lindex $line 2]" -timezone $tz]
        set day [clock format $start -format "%Y-%m-%d"]
        lappend data($day) "$start,[lindex $line 4]"
    }
    foreach {day vals} [array get data] {
        set fn "$datadir/electric-$day.csv"
        if {[file exists $fn] && [file size $fn] != 0} continue
        set fh [open $fn w+]
        puts "writing $fn"
        puts $fh [join $vals \n]
        close $fh
    }
    
    vfs::unmount $zip
 }

 set zip [get_usage $month $user $pass]
 if {$zip == ""} exit 1
 write_csv $zip
 file delete $zip