local await     = require 'await'
local proto     = require 'proto.proto'
local define    = require 'proto.define'
local lang      = require 'language'
local files     = require 'files'
local config    = require 'config'
local core      = require 'core.diagnostics'
local util      = require 'utility'
local ws        = require 'workspace'
local progress  = require "progress"
local client    = require 'client'
local converter = require 'proto.converter'
local loading   = require 'workspace.loading'
local scope     = require 'workspace.scope'
local time      = require 'bee.time'
local ltable    = require 'linked-table'
local furi      = require 'file-uri'
local json      = require 'json'
local fw        = require 'filewatch'
local vm        = require 'vm.vm'

---@class diagnosticProvider
local m = {}
m.cache = {}
m.sleepRest = 0.0
m.scopeDiagCount = 0

local function concat(t, sep)
    if type(t) ~= 'table' then
        return t
    end
    return table.concat(t, sep)
end

local function buildSyntaxError(uri, err)
    local state = files.getState(uri)
    local text  = files.getText(uri)
    if not text or not state then
        return
    end
    local message = lang.script('PARSER_' .. err.type, err.info)

    if err.version then
        local version = err.info and err.info.version or config.get(uri, 'Lua.runtime.version')
        message = message .. ('(%s)'):format(lang.script('DIAG_NEED_VERSION'
            , concat(err.version, '/')
            , version
        ))
    end

    local related = err.info and err.info.related
    local relatedInformation
    if related then
        relatedInformation = {}
        for _, rel in ipairs(related) do
            local rmessage
            if rel.message then
                rmessage = lang.script('PARSER_' .. rel.message)
            else
                rmessage = text:sub(rel.start, rel.finish)
            end
            local relUri = rel.uri or uri
            local relState = files.getState(relUri)
            if relState then
                relatedInformation[#relatedInformation+1] = {
                    message  = rmessage,
                    location = converter.location(relUri, converter.packRange(relState, rel.start, rel.finish)),
                }
            end
        end
    end

    return {
        code     = err.type:lower():gsub('_', '-'),
        range    = converter.packRange(state, err.start, err.finish),
        severity = define.DiagnosticSeverity[err.level],
        source   = lang.script.DIAG_SYNTAX_CHECK,
        message  = message,
        data     = 'syntax',

        relatedInformation = relatedInformation,
    }
end

local function buildDiagnostic(uri, diag)
    local state = files.getState(uri)
    if not state then
        return
    end

    local relatedInformation
    if diag.related then
        relatedInformation = {}
        for _, rel in ipairs(diag.related) do
            local rtext = files.getText(rel.uri)
            if not rtext then
                goto CONTINUE
            end
            local relState = files.getState(rel.uri)
            if not relState then
                goto CONTINUE
            end
            relatedInformation[#relatedInformation+1] = {
                message  = rel.message or rtext:sub(rel.start, rel.finish),
                location = converter.location(rel.uri, converter.packRange(relState, rel.start, rel.finish))
            }
            ::CONTINUE::
        end
    end

    return {
        range    = converter.packRange(state, diag.start, diag.finish),
        source   = lang.script.DIAG_DIAGNOSTICS,
        severity = diag.level,
        message  = diag.message,
        code     = diag.code,
        tags     = diag.tags,
        data     = diag.data,

        relatedInformation = relatedInformation,
    }
end

local function mergeDiags(a, b, c)
    if not a and not b and not c then
        return nil
    end
    local t = {}

    local function merge(diags)
        if not diags then
            return
        end
        for i = 1, #diags do
            local diag = diags[i]
            local severity = diag.severity
            if severity == define.DiagnosticSeverity.Hint
            or severity == define.DiagnosticSeverity.Information then
                if #t > 10000 then
                    goto CONTINUE
                end
            end
            t[#t+1] = diag
            ::CONTINUE::
        end
    end

    merge(a)
    merge(b)
    merge(c)

    if #t == 0 then
        return nil
    end

    return t
end

-- enable `push`, disable `clear`
function m.clear(uri, force)
    await.close('diag:' .. uri)
    if m.cache[uri] == nil and not force then
        return
    end
    m.cache[uri] = nil
    proto.notify('textDocument/publishDiagnostics', {
        uri = uri,
        diagnostics = {},
    })
    log.info('clearDiagnostics', uri)
end

function m.clearCacheExcept(uris)
    local excepts = {}
    for _, uri in ipairs(uris) do
        excepts[uri] = true
    end
    for uri in pairs(m.cache) do
        if not excepts[uri] then
            m.cache[uri] = false
        end
    end
end

function m.clearAll(force)
    if force then
        for luri in files.eachFile() do
            m.clear(luri, force)
        end
    else
        for luri in pairs(m.cache) do
            m.clear(luri)
        end
    end
end

function m.syntaxErrors(uri, ast)
    if #ast.errs == 0 then
        return nil
    end

    local results = {}

    pcall(function ()
        local disables = util.arrayToHash(config.get(uri, 'Lua.diagnostics.disable'))
        for _, err in ipairs(ast.errs) do
            local id = err.type:lower():gsub('_', '-')
            if  not disables[id]
            and not vm.isDiagDisabledAt(uri, err.start, id, true) then
                results[#results+1] = buildSyntaxError(uri, err)
            end
        end
    end)

    return results
end

local function copyDiagsWithoutSyntax(diags)
    if not diags then
        return nil
    end
    local copyed = {}
    for _, diag in ipairs(diags) do
        if diag.data ~= 'syntax' then
            copyed[#copyed+1] = diag
        end
    end
    return copyed
end

---@async
---@param uri uri
---@return boolean
local function isValid(uri)
    if not config.get(uri, 'Lua.diagnostics.enable') then
        return false
    end
    if files.isLibrary(uri, true) then
        local status = config.get(uri, 'Lua.diagnostics.libraryFiles')
        if status == 'Disable' then
            return false
        elseif status == 'Opened' then
            if not files.isOpen(uri) then
                return false
            end
        end
    end
    if ws.isIgnored(uri) then
        local status = config.get(uri, 'Lua.diagnostics.ignoredFiles')
        if status == 'Disable' then
            return false
        elseif status == 'Opened' then
            if not files.isOpen(uri) then
                return false
            end
        end
    end
    local scheme = furi.split(uri)
    local disableScheme = config.get(uri, 'Lua.diagnostics.disableScheme')
    if util.arrayHas(disableScheme, scheme) then
        return false
    end
    return true
end

---@async
function m.doDiagnostic(uri, isScopeDiag)
    if not isValid(uri) then
        return
    end

    await.delay()

    local state = files.getState(uri)
    if not state then
        m.clear(uri)
        return
    end

    local version = files.getVersion(uri)

    local prog <close> = progress.create(uri, lang.script.WINDOW_DIAGNOSING, 0.5)
    prog:setMessage(ws.getRelativePath(uri))

    --log.debug('Diagnostic file:', uri)

    local syntax = m.syntaxErrors(uri, state)

    local diags = {}
    local lastDiag = copyDiagsWithoutSyntax(m.cache[uri])
    local function pushResult()
        tracy.ZoneBeginN 'mergeSyntaxAndDiags'
        local _ <close> = tracy.ZoneEnd
        local full = mergeDiags(syntax, lastDiag, diags)
        --log.debug(('Pushed [%d] results'):format(full and #full or 0))
        if not full then
            m.clear(uri)
            return
        end

        if util.equal(m.cache[uri], full) then
            return
        end
        m.cache[uri] = full

        if not files.exists(uri) then
            m.clear(uri)
            return
        end

        proto.notify('textDocument/publishDiagnostics', {
            uri = uri,
            version = version,
            diagnostics = full,
        })
        log.debug('publishDiagnostics', uri, #full)
    end

    pushResult()

    local lastPushClock = time.time()
    ---@async
    xpcall(core, log.error, uri, isScopeDiag, function (result)
        diags[#diags+1] = buildDiagnostic(uri, result)

        if not isScopeDiag and time.time() - lastPushClock >= 500 then
            lastPushClock = time.time()
            pushResult()
        end
    end, function (checkedName)
        if not lastDiag then
            return
        end
        for i, diag in ipairs(lastDiag) do
            if diag.code == checkedName then
                lastDiag[i] = lastDiag[#lastDiag]
                lastDiag[#lastDiag] = nil
            end
        end
    end)

    lastDiag = nil
    pushResult()
end

---@param uri uri
function m.resendDiagnostic(uri)
    local full = m.cache[uri]
    if not full then
        return
    end

    if not files.exists(uri) then
        m.clear(uri)
        return
    end

    local version = files.getVersion(uri)

    proto.notify('textDocument/publishDiagnostics', {
        uri = uri,
        version = version,
        diagnostics = full,
    })
    log.debug('publishDiagnostics', uri, #full)
end

---@async
---@return table|nil result
---@return boolean? unchanged
function m.pullDiagnostic(uri, isScopeDiag)
    if not isValid(uri) then
        return nil, util.equal(m.cache[uri], nil)
    end

    await.delay()

    local state = files.getState(uri)
    if not state then
        return nil, util.equal(m.cache[uri], nil)
    end

    local prog <close> = progress.create(uri, lang.script.WINDOW_DIAGNOSING, 0.5)
    prog:setMessage(ws.getRelativePath(uri))

    local syntax = m.syntaxErrors(uri, state)
    local diags = {}

    xpcall(core, log.error, uri, isScopeDiag, function (result)
        diags[#diags+1] = buildDiagnostic(uri, result)
    end)

    local full = mergeDiags(syntax, diags)

    if util.equal(m.cache[uri], full) then
        return full, true
    end

    m.cache[uri] = full

    return full
end

---@param event string
---@param uri uri
function m.refreshScopeDiag(event, uri)
    if not ws.isReady(uri) then
        return
    end
    local scp     = scope.getScope(uri)
    local scopeID = 'diagnosticsScope:' .. scp:getName()
    await.close(scopeID)

    local eventConfig = config.get(uri, 'Lua.diagnostics.workspaceEvent')

    if eventConfig ~= event then
        return
    end

    ---@async
    await.call(function ()
        local delay = config.get(uri, 'Lua.diagnostics.workspaceDelay') / 1000
        if delay < 0 then
            return
        end
        await.sleep(math.max(delay, 0.2))
        m.diagnosticsScope(uri)
    end)
end

---@param uri uri
function m.refresh(uri)
    if not ws.isReady(uri) then
        return
    end

    await.close('diag:' .. uri)
    ---@async
    await.call(function ()
        await.setID('diag:' .. uri)
        await.sleep(0.1)
        xpcall(m.doDiagnostic, log.error, uri)
    end)
end

---@async
local function askForDisable(uri)
    if m.dontAskedForDisable then
        return
    end
    local delay = 30
    local delayTitle = lang.script('WINDOW_DELAY_WS_DIAGNOSTIC', delay)
    local item = proto.awaitRequest('window/showMessageRequest', {
        type    = define.MessageType.Info,
        message = lang.script.WINDOW_SETTING_WS_DIAGNOSTIC,
        actions = {
            {
                title = lang.script.WINDOW_DONT_SHOW_AGAIN,
            },
            {
                title = delayTitle,
            },
            {
                title = lang.script.WINDOW_DISABLE_DIAGNOSTIC,
            },
        }
    })
    if not item then
        return
    end
    if     item.title == lang.script.WINDOW_DONT_SHOW_AGAIN then
        m.dontAskedForDisable = true
    elseif item.title == delayTitle then
        client.setConfig {
            {
                key    = 'Lua.diagnostics.workspaceDelay',
                action = 'set',
                value  = delay * 1000,
                uri    = uri,
            }
        }
    elseif item.title == lang.script.WINDOW_DISABLE_DIAGNOSTIC then
        client.setConfig {
            {
                key    = 'Lua.diagnostics.workspaceDelay',
                action = 'set',
                value  = -1,
                uri    = uri,
            }
        }
    end
end

local function clearMemory()
    if m.scopeDiagCount > 0 then
        return
    end
    vm.clearNodeCache()
    collectgarbage()
end

---@async
function m.awaitDiagnosticsScope(suri, callback)
    local scp = scope.getScope(suri)
    if scp.type == 'fallback' then
        return
    end
    while loading.count() > 0 do
        await.sleep(1.0)
    end
    m.scopeDiagCount = m.scopeDiagCount + 1
    local scopeDiag <close> = util.defer(function ()
        m.scopeDiagCount = m.scopeDiagCount - 1
        clearMemory()
    end)
    local clock = os.clock()
    local bar <close> = progress.create(suri, lang.script.WORKSPACE_DIAGNOSTIC, 1)
    local cancelled
    bar:onCancel(function ()
        log.info('Cancel workspace diagnostics')
        cancelled = true
        ---@async
        await.call(function ()
            askForDisable(suri)
        end)
    end)
    local uris = files.getAllUris(suri)
    local sortedUris = ltable()
    for _, uri in ipairs(uris) do
        if files.isOpen(uri) then
            sortedUris:pushHead(uri)
        else
            sortedUris:pushTail(uri)
        end
    end
    log.info(('Diagnostics scope [%s], files count:[%d]'):format(scp:getName(), #uris))
    local i = 0
    for uri in sortedUris:pairs() do
        while loading.count() > 0 do
            await.sleep(1.0)
        end
        i = i + 1
        bar:setMessage(('%d/%d'):format(i, #uris))
        bar:setPercentage(i / #uris * 100)
        callback(uri)
        await.delay()
        if cancelled then
            log.info('Break workspace diagnostics')
            break
        end
    end
    bar:remove()
    log.info(('Diagnostics scope [%s] finished, takes [%.3f] sec.'):format(scp:getName(), os.clock() - clock))
end

function m.diagnosticsScope(uri, force)
    if not ws.isReady(uri) then
        return
    end
    if not force and not config.get(uri, 'Lua.diagnostics.enable') then
        m.clearAll()
        return
    end
    if not force and config.get(uri, 'Lua.diagnostics.workspaceDelay') < 0 then
        return
    end
    local scp = scope.getScope(uri)
    local id = 'diagnosticsScope:' .. scp:getName()
    await.close(id)
    await.call(function () ---@async
        await.sleep(0.0)
        m.awaitDiagnosticsScope(uri, function (fileUri)
            xpcall(m.doDiagnostic, log.error, fileUri, true)
        end)
    end, id)
end

---@async
function m.pullDiagnosticScope(callback)
    local processing = 0

    for _, scp in ipairs(scope.folders) do
        if  ws.isReady(scp.uri)
        and config.get(scp.uri, 'Lua.diagnostics.enable') then
            local id = 'diagnosticsScope:' .. scp:getName()
            await.close(id)
            await.call(function () ---@async
                processing = processing + 1
                local _ <close> = util.defer(function ()
                    processing = processing - 1
                end)

                local delay = config.get(scp.uri, 'Lua.diagnostics.workspaceDelay') / 1000
                if delay < 0 then
                    return
                end
                print(delay)
                await.sleep(math.max(delay, 0.2))
                print('start')

                m.awaitDiagnosticsScope(scp.uri, function (fileUri)
                    local suc, result, unchanged = xpcall(m.pullDiagnostic, log.error, fileUri, true)
                    if suc then
                        callback {
                            uri       = fileUri,
                            result    = result,
                            unchanged = unchanged,
                            version   = files.getVersion(fileUri),
                        }
                    end
                end)
            end, id)
        end
    end

    -- sleep for ever
    while true do
        await.sleep(1.0)
    end
end

function m.refreshClient()
    log.debug('Refresh client diagnostics')
    proto.request('workspace/diagnostic/refresh', json.null)
end

ws.watch(function (ev, uri)
    if ev == 'reload' then
        m.diagnosticsScope(uri)
        m.refreshClient()
    end
end)

files.watch(function (ev, uri) ---@async
    if ev == 'remove' then
        m.clear(uri)
        m.refresh(uri)
    elseif ev == 'update' then
        m.refresh(uri)
        m.refreshScopeDiag('OnChange', uri)
    elseif ev == 'open' then
        if ws.isReady(uri) then
            m.resendDiagnostic(uri)
            xpcall(m.doDiagnostic, log.error, uri)
        end
    elseif ev == 'close' then
        if files.isLibrary(uri, true)
        or ws.isIgnored(uri) then
            m.clear(uri)
        end
    elseif ev == 'save' then
        m.refreshScopeDiag('OnSave', uri)
    end
end)

config.watch(function (uri, key, value, oldValue)
    if util.stringStartWith(key, 'Lua.diagnostics')
    or util.stringStartWith(key, 'Lua.spell')
    or util.stringStartWith(key, 'Lua.doc') then
        if value ~= oldValue then
            m.diagnosticsScope(uri)
            m.refreshClient()
        end
    end
end)

fw.event(function (ev, path)
    if util.stringEndWith(path, '.editorconfig') then
        for _, scp in ipairs(ws.folders) do
            m.diagnosticsScope(scp.uri)
            m.refreshClient()
        end
    end
end)

return m