--[[
    the main user interface for memoire
]]

local Prompt = dofile "prompt.lua"
local review = dofile "review.lua"
local loader = dofile "loader.lua"

--[[
    checks (returns boolean) if a response-string is affirmative
]]
local function isyes(s)
    local f = s:sub(1, 1):lower()
    return f == "y" or f == "t"
end

--[[
    clears the terminal
    implementation may be platform-specific
]]
local function clear()
    -- XTerm
    io.write("\x1bc")
end

--[[
    check action based on first command-line argument;
    if nothing valid given, default to help
]]
local action = nil
if arg[1] then
    local fc = arg[1]:sub(1, 1)
    if fc == "a" or fc == "h" or fc == "r" or fc == "s" then
        action = fc
    else
        action = "h"
    end
else
    action = "h"
end

local deckfname = "example.rec"
if arg[2] then
    deckfname = arg[2]
end

--[[
    do requested action
]]
-- Add card(s)
if action == "a" then
    local deck = loader.load(deckfname)
    if deck then
        io.write("Reading prompts -- press Ctrl-D to stop\n")
        local rt = io.read("a")
        local cardctr = 0
        local prctr = 0
        for pt in rt:gmatch("(..-)\n\n") do
            local nc = {}
            -- these Prompts will just be converted to Rec, so we don't need to exclude answers from prompt-text
            for _re in pt:gmatch("%{[^%}]+%}") do
                table.insert(nc, Prompt:new(pt, "", os.time(), 30, 0, 0))
                prctr = prctr + 1
            end
            table.insert(deck, nc)
            cardctr = cardctr + 1
        end
        io.write(string.format(
            "Added %d cards (%d prompts)\n",
            cardctr,
            prctr
        ))
        if cardctr > 0 then
            loader.save(deckfname, deck)
        end
    else
        io.write("Failed to load deck\n")
    end
-- Help
elseif action == "h" then
    io.write(string.format(
        "Usage: %s ACTION [REPO]\n\nACTION may be one of\n    (a)dd card\n    (h)elp\n    (r)eview session\n    (s)tatistics\n",
        arg[0]
    ))
-- Review session
elseif action == "r" then
    local deck = loader.load(deckfname)
    if deck then
        -- collect list of index-pairs for prompts to be reviewed this session
        local ctrt = {}
        for i, cg in ipairs(deck) do
            for j, pr in ipairs(cg) do
                if review.should(pr) then
                    table.insert(ctrt, { i, j })
                end
            end
        end
        io.write(string.format(
            "%d prompts are ready for review.\nHow many to review in this session? ", #ctrt
        ))
        local climt = io.read("l")
        local climn = tonumber(climt)
        if climn then
            local start = os.time()
            -- review propmts in this session's set
            for ind, ip in ipairs(ctrt) do
                if ind > climn then
                    break
                end
                local pr = deck[ip[1]][ip[2]]
                -- remove braces for display
                local pst = pr.text:gsub("%{([^{}]+)%}", "%1")
                local st = os.time()
                io.write(string.format(
                    "%s\n",
                    pst:gsub("%%A", "___")
                ))
                io.read("l")
                io.write(string.format(
                    "%s\nDid you get it? ",
                    pst:gsub("%%A", pr.ans)
                ))
                local resp = io.read("l")
                review.update(deck[ip[1]][ip[2]], st, isyes(resp))
                clear()
            end
            local endt = os.time()
            io.write(string.format(
                "Reviewed %d prompts in %d seconds\n",
                math.min(#ctrt, climn),
                endt - start
            ))
            if #ctrt > 0 then
                io.write(string.format(
                    "(%f seconds per card)\n",
                    (endt - start) / math.min(#ctrt, climn)
                ))
                loader.save(deckfname, deck)
            end
        else
            io.write("Input not a number -- aborting\n")
        end
    else
        io.write("Failed to load deck\n")
    end
-- Statistics
elseif action == "s" then
    -- TODO
else
    io.write "unreachable"
end