local cache = require("cache")
local sql = require("lsqlite3")
local db = require("db")
local queries = require("queries")
local util = require("util")
local tags = require("tags")
require("global")

local stmnt_tags_get, stmnt_stories_get

local oldconfigure = configure
function configure(...)
	stmnt_tags_get = db.sqlassert(db.conn:prepare(queries.select_suggest_tags))
	stmnt_stories_get = db.sqlassert(db.conn:prepare(queries.select_site_index))
	return oldconfigure(...)
end

local function suggest_tags(req,data)
	--[[
	Prevent a malicious user from injecting '%' into the string
	we're searching for, potentially causing a DoS with a
	sufficiently backtrack-ey search/tag combination.
	]]
	assert(data:match("^[a-zA-Z0-9,%s-]+$"),string.format("Bad characters in tag: %q",data))
	stmnt_tags_get:bind_names{
		match = data .. "%"
	}
	local tags = {data}
	for tag in stmnt_tags_get:rows() do
		table.insert(tags,tag[1])
	end
	stmnt_tags_get:reset()
	http_response_header(req,"Content-Type","text/plain")
	http_response(req,200,table.concat(tags,";"))
end

--[[
A poor mans json builder, since I don't need one big enough to pull in a
dependency for it (yet)
]]
local function poor_json(builder, ltbl)
	local function write_bool(builder,bool)
		table.insert(builder,bool and "true" or "false")
	end
	local function write_number(builder,num)
		local number
		if num % 1 == 0 then
			num = string.format("%d",num)
		else
			num = string.format("%f",num)
		end
		table.insert(builder,num)
	end
	local function write_string(builder,s)
		table.insert(builder, string.format("%q",s))
	end
	local function write_array(builder,tbl)
		table.insert(builder,"[")
		for _,item in ipairs(tbl) do
			write_string(builder,item)
			table.insert(builder,",")
		end
		if #tbl > 0 then
			table.remove(builder,#builder) -- Remove the last comma
		end
		table.insert(builder,"]")
	end
	local lua_to_json = {
		boolean = write_bool,
		number = write_number,
		string = write_string,
		table = write_array
	}
	table.insert(builder,"{")
	for k,v in pairs(ltbl) do
		assert(type(k) == "string", "Field was not a string, was: " .. type(k))
		table.insert(builder,string.format("%q",k))
		table.insert(builder,":")
		assert(lua_to_json[type(v)], "Unknown type for json:" .. type(v) .. " at " .. k)
		lua_to_json[type(v)](builder,v)
		table.insert(builder,",")
	end
	table.remove(builder,#builder) -- Remove the last comma before closing object
	table.insert(builder,"}")
	table.insert(builder,",") -- Can't do this on the same line as above
	                          -- we need to remove the last comma, but not }
end

local function get_stories(req,data)
	local nstories = tonumber(data)
	stmnt_stories_get:bind_names{offset=nstories}
	local builder = setmetatable({'{"stories":['},table)
	for id, title, anon, time, author, hits, ncomments in db.sql_rows(stmnt_stories_get) do
		local story = {
			url = util.encode_id(id),
			title = title,
			isanon = tonumber(anon) == 1,
			posted = os.date("%B %d %Y",tonumber(time)),
			author = author,
			tags = tags.get(id),
			hits = hits,
			ncomments = ncomments
		}
		poor_json(builder,story)
	end
	table.remove(builder,#builder) -- Remove last comma before closing list
	table.insert(builder,"]}")
	stmnt_stories_get:reset()
	http_response_header(req,"Content-Type","text/plain")
	http_response(req,200,table.concat(builder))
end

local api_points = {}
local function register_api(call,func)
	api_points[call] = func
end
register_api("suggest",suggest_tags)
register_api("stories",get_stories)
local function api_get(req)
	http_request_populate_qs(req)
	local call = assert(http_argument_get_string(req,"call"))
	local data = assert(http_argument_get_string(req,"data"))
	assertf(api_points[call], "Unknown api endpoint: %s", call)
	api_points[call](req,data)
end
return api_get