local rpc = require 'rpc'
local lang = require 'language'

local command = {}

local function isContainPos(obj, start, finish)
    if obj.start <= start and obj.finish >= finish then
        return true
    end
    return false
end

local function isInString(vm, start, finish)
    return vm:eachSource(function (source)
        if source.type == 'string' and isContainPos(source, start, finish) then
            return true
        end
    end)
end

local function posToRange(lines, start, finish)
    local start_row,  start_col  = lines:rowcol(start)
    local finish_row, finish_col = lines:rowcol(finish)
    return {
        start = {
            line = start_row - 1,
            character = start_col - 1,
        },
        ['end'] = {
            line = finish_row - 1,
            character = finish_col,
        },
    }
end

--- @param lsp LSP
--- @param data table
command['lua.removeSpace'] = function (lsp, data)
    local uri = data.uri
    local vm, lines = lsp:getVM(uri)
    if not vm then
        return
    end

    local textEdit = {}
    for i = 1, #lines do
        local line = lines:line(i)
        local pos = line:find '[ \t]+$'
        if pos then
            local start, finish = lines:range(i)
            start = start + pos - 1
            if isInString(vm, start, finish) then
                goto NEXT_LINE
            end
            textEdit[#textEdit+1] = {
                range = posToRange(lines, start, finish),
                newText = '',
            }
            goto NEXT_LINE
        end

        ::NEXT_LINE::
    end

    if #textEdit == 0 then
        return
    end

    rpc:request('workspace/applyEdit', {
        label = lang.script.COMMAND_REMOVE_SPACE,
        edit = {
            changes = {
                [uri] = textEdit,
            }
        },
    })
end

local opMap = {
    ['+']  = true,
    ['-']  = true,
    ['*']  = true,
    ['/']  = true,
    ['//'] = true,
    ['^']  = true,
    ['<<'] = true,
    ['>>'] = true,
    ['&']  = true,
    ['|']  = true,
    ['~']  = true,
    ['..'] = true,
}

local literalMap = {
    ['number']  = true,
    ['boolean'] = true,
    ['string']  = true,
    ['table']   = true,
}

--- @param lsp LSP
--- @param data table
command['lua.solve'] = function (lsp, data)
    local uri = data.uri
    local vm, lines = lsp:getVM(uri)
    if not vm then
        return
    end

    local start = lines:position(data.range.start.line + 1, data.range.start.character + 1)
    local finish = lines:position(data.range['end'].line + 1, data.range['end'].character)

    local result = vm:eachSource(function (source)
        if not isContainPos(source, start, finish) then
            return
        end
        if source.op ~= 'or' then
            return
        end
        local first  = source[1]
        local second = source[2]
        -- (a + b) or 0 --> a + (b or 0)
        do
            if opMap[first.op]
                and first.type ~= 'unary'
                and not second.op
                and literalMap[second.type]
            then
                return {
                    start = source[1][2].start,
                    finish = source[2].finish,
                }
            end
        end
        -- a or (b + c) --> (a or b) + c
        do
            if opMap[second.op]
                and second.type ~= 'unary'
                and not first.op
                and literalMap[second[1].type]
            then
                return {
                    start = source[1].start,
                    finish = source[2][1].finish,
                }
            end
        end
    end)

    if not result then
        return
    end

    rpc:request('workspace/applyEdit', {
        label = lang.script.COMMAND_ADD_BRACKETS,
        edit = {
            changes = {
                [uri] = {
                    {
                        range = posToRange(lines, result.start, result.start - 1),
                        newText = '(',
                    },
                    {
                        range = posToRange(lines, result.finish + 1, result.finish),
                        newText = ')',
                    },
                }
            }
        },
    })
end

--- @param lsp LSP
--- @param params table
return function (lsp, params)
    local name = params.command
    if not command[name] then
        return
    end
    local result = command[name](lsp, params.arguments[1])
    return result
end