#! /usr/bin/env lua

require "libs.shcmd"

local tvcal = { ["desc"] = "Display TV calendar" }

local tvcaldata = {}

local tvcaldata_timestamp

-- Function from PIL

local function pairsByKeys (t, f)

    local a = {}

    for n in pairs(t) do table.insert(a, n) end

    table.sort(a, f)

    local i = 0      -- iterator variable

    local iter = function ()   -- iterator function

        i = i + 1

        if a[i] == nil then return nil

        else return a[i], t[a[i]]

        end

    end

    return iter

end

local function parse_webpage (url)

    local contents = shcmd("curl "..url)

    if not contents then

        return nil, "Could not fetch calendar, please try again later!"

    end

    -- Work around frackin ugly end of line characters... :/

    local eol = "[%s"..string.char(13).."]*"

    -- Regex for each day

    local tabregex = '<td id="d_(%d+_%d+_%d%d%d%d)" class="t?o?day"%s*>'..

                     '%s*(.-)%s*</td>'

    -- Regex for parsing one day

    local epregex = '<p[^>]*>'..

                      '<a href=[^>]+>([^<]+)</a>'..eol..        -- Name

                      '<br /><a href=[^>]+>([^<]+)</a>'..eol..  -- Episode

                    '</p>'

    -- loop over all days

    for day, daytab in string.gmatch(contents, tabregex) do

        local d, m, y = day:match("^(%d+)_(%d+)_(%d%d%d%d)$")

        day = string.format("%04d-%02d-%02d", y, m, d)

        local shows = {}

        -- Loop over all episodes of a day

        for name, ep in string.gmatch(daytab, epregex) do

            name = name:gsub(""", "\""):gsub("&", "&")

            name = name:gsub("&lt;", "<"):gsub("&gt;", ">")

            name = name:gsub("'", "'")

            name = name:gsub("%s*\n%s*", "  ")

            local obj = {

                ["name"] = name,

                ["ep"] = ep

                }

            table.insert(shows, obj)

        end

        tvcaldata[day] = shows

    end

    tvcaldata_timestamp = os.date("%F")

    return true

end

local function tvcal_by_date (d)

    if not tvcaldata[d] then

        return "No episode found for this date ("..d..")"

    end

    local r = "Shows on " .. d .. ":\n"

    for i,j in ipairs(tvcaldata[d]) do

        r = r .. j.name .. " (" ..j.ep .. ")\n"

    end

    r = r:gsub("\n+$", "")

    return r

end

local function tvcal_by_name (name, plain)

    local action = plain and "contain" or "match"

    local r = ""

    name = name:lower()

    for day, obj in pairsByKeys(tvcaldata) do

        for i,j in ipairs(obj) do

            if j.name:lower():find(name, 1, plain) then

                r = r .. day .. "\t" .. j.name .. " (" ..j.ep .. ")\n"

            end

        end

    end

    if r == "" then

        return "No episode found "..action.."ing this string"

    end

    r = r:gsub("\n+$", "")

    return "Episodes "..action.."ing \""..name.."\":\n" .. r

end

function tvcal.cmd (arg)

    if not tvcaldata_timestamp or tvcaldata_timestamp ~= os.date("%F") then

        tvcaldata = {} -- Empty the previous list

        local r, err = parse_webpage("http://www.pogdesign.co.uk/cat/")

        if not r then return nil, err end

        -- Fetch next month as well...

        local m = tonumber(os.date("%m"))+1

        local y = os.date("%Y")

        if m > 12 then m = 1; y = y + 1; end

        parse_webpage("http://www.pogdesign.co.uk/cat/"..m.."-"..y)

    end

    if not arg or arg == "today" then

        arg = os.date("%F")

    elseif arg == "tomorrow" then

        arg = os.date("%F", os.date("%s")+86400)

    elseif arg:match("^%+%d+$") then

        local n = tonumber(arg:match("^%+(%d+)$"))

        if n < 60 then

            arg = os.date("%F", os.date("%s")+86400*n)

        end

    end

    if arg:match("^%d%d%d%d%-%d%d%-%d%d$") then

        return tvcal_by_date(arg)

    end

    -- Is it a pattern? (string surrounded by quotes)

    local plain = arg:match('^"(.*)"$')

    if plain then

        arg = plain

        plain = false

    else

        plain = true

    end

    return tvcal_by_name(arg, plain)

end

mcbot_register_command("tvcal", tvcal)