--[[
    a card consists of a base note, a card type, a creation timestamp,
    and a list of prompts

    timestamps are seconds from the Unix epoch
]]

local Card = {}
Card.__index = Card

function Card:new(ctable)
    local o = { note = "", ct = "bmc", created = os.time(), pr = {} }
    setmetatable(o, self)
    for k, v in pairs(ctable) do
        if o[k] then o[k] = v end
    end
    return o
end

function Card:__tostring()
    return string.format("\"%s\" (%s), %d (%d)", self.note, self.ct, #self.pr, self.created)
end

--[[
    extracts `Card`s from a record-based deck
    returns a table of `Card`s
]]
function Card:fromrecs(recs, conf)
    local ret = {}
    for i, rec in ipairs(recs) do
        local bn
        if rec.PromptText then bn = rec.PromptText[1] end
        if rec.BaseNote then bn = rec.BaseNote[1] end
        if bn then
            local cc = Card:new({ note = bn, ct = (rec.CardType or {})[1], created = (rec.Created or {})[1] })
            if cc.ct == "bmc" then
                local m, n = cc.note:find("{[^}]+}")
                local ctr = 1
                while m do
                    table.insert(cc.pr, Prompt:new({
                        card = cc,
                        ind = m,
                        time = tonumber((rec.LastReview or {})[ctr]),
                        delay = tonumber((rec.LastDelay or {})[ctr]),
                        succ = tonumber((rec.Successes or {})[ctr]),
                        fail = tonumber((rec.Failures or {})[ctr]),
                        ease = tonumber((rec.Ease or {})[ctr]),
                    }))
                    m, n = cc.note:find("{[^}]+}", n)
                    ctr = ctr + 1
                end
                table.insert(ret, cc)
            elseif cc.ct == "cys" then
                local m = cc.note:find(";;.")
                local ctr = 1
                local segs = {}
                while m do
                    table.insert(segs, m + 2)
                    m = cc.note:find(";;.", m + 2)
                end
                for i, m in ipairs(segs) do
                    table.insert(cc.pr, Prompt:new({
                        card = cc,
                        ind = { segs[i == 1 and #segs or i - 1], m },
                        time = tonumber((rec.LastReview or {})[ctr]),
                        delay = tonumber((rec.LastDelay or {})[ctr]),
                        succ = tonumber((rec.Successes or {})[ctr]),
                        fail = tonumber((rec.Failures or {})[ctr]),
                        ease = tonumber((rec.Ease or {})[ctr]),
                    }))
                    ctr = ctr + 1
                end
                table.insert(ret, cc)
             elseif cc.ct == "pwc" then
                local m = cc.note:find(";;")
                local ctr = 1
                local segs = {}
                while m do
                    table.insert(segs, m + 2)
                    m = cc.note:find(";;", m + 2)
                end
                for i, m in ipairs(segs) do
                    local p = cc.note:find(";;", m) or #cc.note
                    local b = cc.note:find("{[^}]+}", m)
                    if b and b < p then
                        for j, n in ipairs(segs) do
                            if i ~= j then
                                table.insert(cc.pr, Prompt:new({
                                    card = cc,
                                    ind = { n, m },
                                    time = tonumber((rec.LastReview or {})[ctr]),
                                    delay = tonumber((rec.LastDelay or {})[ctr]),
                                    succ = tonumber((rec.Successes or {})[ctr]),
                                    fail = tonumber((rec.Failures or {})[ctr]),
                                    ease = tonumber((rec.Ease or {})[ctr]),
                                }))
                                ctr = ctr + 1
                            end
                        end
                    end
                 end
                table.insert(ret, cc)
            elseif cc.ct == "seq" then
                local m, n = cc.note:find(";;")
                local ctr = 1
                while m do
                    table.insert(cc.pr, Prompt:new({
                        card = cc,
                        ind = n + 1,
                        time = tonumber((rec.LastReview or {})[ctr]),
                        delay = tonumber((rec.LastDelay or {})[ctr]),
                        succ = tonumber((rec.Successes or {})[ctr]),
                        fail = tonumber((rec.Failures or {})[ctr]),
                        ease = tonumber((rec.Ease or {})[ctr]),
                    }))
                    m, n = cc.note:find(";;", n)
                    ctr = ctr + 1
                end
                table.insert(ret, cc)
            else
                print("error: unsupported card type " .. cc.ct)
            end
        end
    end
    return ret
end

--[[
    serialises a `Card` to a record
    returns a table mapping labels to value-lists
]]
function Card:torec()
    local ret = { BaseNote = { self.note }, CardType = { self.ct }, Created = { self.created }, LastReview = {}, LastDelay = {}, Successes = {}, Failures = {}, Ease = {} }
    for i, pr in ipairs(self.pr) do
        ret.LastReview[i] = pr.time
        ret.LastDelay[i] = pr.delay
        ret.Successes[i] = pr.succ
        ret.Failures[i] = pr.fail
        ret.Ease[i] = pr.ease
    end
    return ret
end

return Card