local keymap = require("ow.lsp.keymap")
local utils = require("ow.utils")

---@class Linter
local Linter = require("ow.lsp.linter")

---@class MasonPackage
local MasonPackage = require("ow.lsp.package")

---@class Server
---@field name? string
---@field mason? MasonPackage
---@field client? vim.lsp.Client
---@field attached_buffers? number[]
---@field manager lspconfig.Manager
---@field linters? Linter[]
---@field config ServerConfig
local M = {}

M.__index = M

---@class ServerConfig
---@field enable? boolean
---@field dependencies? string[]
---@field mason? string|MasonPackageConfig
---@field keymaps? Keymap[]
---@field linters? LinterConfig[]
---@field settings_file? string
---@field lspconfig? lspconfig.Config
M.config = {}

--- Validate ServerConfig
---@param config ServerConfig
---@return boolean
function M.validate(name, config)
    local ok, resp = pcall(vim.validate, { config = { config, { "table" } } })

    if ok then
        ok, resp = pcall(vim.validate, {
            enable = { config.enable, { "boolean" }, true },
            dependencies = {
                config.dependencies,
                function(f)
                    return utils.is_list_or_nil(f, "string")
                end,
                "list of strings or nil",
            },
            mason = { config.mason, { "string", "table" }, true },
            keymaps = {
                config.keymaps,
                function(f)
                    if not f then
                        return true
                    end

                    if not utils.is_list(f, "table") then
                        return false
                    end

                    for _, key in ipairs(f) do
                        local o, r = pcall(vim.validate, {
                            mode = { key.mode, { "string", "table" } },
                            lhs = { key.lhs, "string" },
                            rhs = { key.rhs, { "string", "function" } },
                            opts = { key.opts, "table", true },
                        })

                        if not o then
                            utils.err(("Invalid keymap:\n%s"):format(r))
                            return false
                        end
                    end

                    return true
                end,
                "list of keymaps",
            },
            lspconfig = { config.lspconfig, { "table" }, true },
        })
    end

    if not ok then
        utils.err(("Invalid config for %s:\n%s"):format(name, resp))
        return false
    end

    return true
end

--- Called when language server attaches
---@param client vim.lsp.Client
---@param bufnr integer
function M:on_attach(client, bufnr)
    if self.client and self.client.id ~= client.id then
        self.client:stop(true)
    end
    self.client = client
    self.attached_buffers = self.attached_buffers or {}
    table.insert(self.attached_buffers, bufnr)

    keymap:init(self, bufnr)
    if self.linters then
        for _, linter in ipairs(self.linters) do
            local bin = linter.config.cmd[1]
            if utils.is_executable(bin) then
                linter:init(bufnr)
            else
                utils.warn(
                    ("Not adding %s because it is not installed"):format(bin)
                )
            end
        end
    end

    -- For document highlight
    vim.cmd.highlight({ "link LspReferenceRead Visual", bang = true })
    vim.cmd.highlight({ "link LspReferenceText Visual", bang = true })
    vim.cmd.highlight({ "link LspReferenceWrite Visual", bang = true })

    ---@alias lsp.Client vim.lsp.Client
    -- require("lsp_compl").attach(client, bufnr, {
    --     server_side_fuzzy_completion = true,
    -- })
end

--- Configure the LSP client
function M:configure_client()
    local lspconfig = require("lspconfig")

    local capabilities = vim.lsp.protocol.make_client_capabilities()
    local cmp_nvim_lsp = utils.try_require("cmp_nvim_lsp")
    if cmp_nvim_lsp then
        capabilities = vim.tbl_deep_extend(
            "force",
            capabilities,
            cmp_nvim_lsp.default_capabilities()
        )
    end

    -- local epo = utils.try_require("epo")
    -- if epo then
    --     capabilities = vim.tbl_deep_extend(
    --         "force",
    --         capabilities,
    --         epo.register_cap()
    --     )
    -- end

    -- local lsp_compl = utils.try_require("lsp_compl")
    -- if lsp_compl then
    --     capabilities = vim.tbl_deep_extend("force", capabilities, lsp_compl.capabilities())
    -- end
    --

    self.config.lspconfig.capabilities = capabilities
    self.config.lspconfig.on_attach = function(client, bufnr)
        local ok, ret = pcall(self.on_attach, self, client, bufnr)
        if not ok then
            utils.err(
                ("Failed to load on_attach for %s:\n%s"):format(self.name, ret),
                "lsp.server:configure_client"
            )
        end
    end

    if self.config.settings_file then
        local file = io.open(self.config.settings_file, "r")
        if not file then
            utils.warn(
                ("Failed to open file for reading: %s"):format(
                    self.config.settings_file
                )
            )
        else
            local json = file:read("*all")
            file:close()
            local ok, resp = pcall(
                vim.json.decode,
                json,
                { luanil = { object = true, array = true } }
            )
            if not ok then
                utils.warn(
                    ("Failed to parse json file %s:%s"):format(
                        self.config.settings_file,
                        resp
                    )
                )
            else
                self.config.lspconfig.settings = vim.tbl_deep_extend(
                    "force",
                    self.config.lspconfig.settings or {},
                    resp
                )
            end
        end
    end

    local ok, ret = pcall(lspconfig[self.name].setup, self.config.lspconfig)
    if not ok then
        utils.err(
            ("Failed to setup LSP server %s with lspconfig: %s"):format(
                self.name,
                ret
            )
        )
        return
    end

    self.manager = lspconfig[self.name].manager
    for _, bufnr in ipairs(self:get_ft_buffers()) do
        self.manager:try_add_wrapper(bufnr)
    end

    if self.config.linters then
        self.linters = {}
        for i, config in ipairs(self.config.linters) do
            local linter =
                Linter.new(("%s_linter%d"):format(self.name, i), config)

            if linter then
                table.insert(self.linters, linter)
            end
        end
    end
end

function M:get_ft_buffers()
    local filetypes = self.config.lspconfig.filetypes or {}
    if not vim.list_contains(filetypes, self.config.lspconfig.filetype) then
        table.insert(filetypes, self.config.lspconfig.filetype)
    end
    if #filetypes == 0 then
        return {}
    end
    return vim.tbl_filter(function(bufnr)
        return vim.list_contains(filetypes, vim.bo[bufnr].filetype)
    end, vim.api.nvim_list_bufs())
end

--- Check for and return missing dependencies
---@return table<string>
function M:get_missing_unmanaged_deps()
    local missing_deps = {}
    if self.config.dependencies ~= nil then
        for _, dep in ipairs(self.config.dependencies) do
            if not utils.is_executable(dep) then
                table.insert(missing_deps, dep)
            end
        end
    end
    return missing_deps
end

--- Install LSP server
---@param on_done fun(success: boolean)?
function M:install(on_done)
    --- Handle install result
    ---@param success boolean
    local function handle_result(success)
        if not success then
            self.config.enable = false
        end
        if on_done then
            on_done(success)
        end
    end

    self.mason:install_with_dependencies(handle_result)
end

--- Setup LSP server
function M:setup(on_done)
    local missing_deps = self:get_missing_unmanaged_deps()

    if #missing_deps > 0 then
        utils.warn(
            (
                "Disabling %s because the following package(s)"
                .. "are not installed: %s"
            ):format(self.name, table.concat(missing_deps, ", "))
        )
        self.config.enable = false
        return
    end

    if self.mason then
        self:install(function(success)
            if success then
                self:configure_client()
            end

            if on_done then
                on_done(success)
            end
        end)
    elseif vim.fn.executable(self.config.lspconfig.cmd[1]) == 1 then
        self:configure_client()
    else
        utils.warn(self.name .. " not installed, disabling")
        self.config.enable = false
    end
end

--- Load autocmd for setting up LSP server upon entering a buffer of related
--- filetype
function M:init(on_done)
    local group = vim.api.nvim_create_augroup("lsp_bootstrap_" .. self.name, {})
    vim.api.nvim_create_autocmd("FileType", {
        once = true,
        pattern = self.config.lspconfig.filetypes or {},
        callback = function()
            self:setup(on_done)
        end,
        group = group,
    })
end

function M:deinit()
    if self.attached_buffers then
        for _, bufnr in ipairs(self.attached_buffers) do
            keymap:deinit(bufnr)
        end
    end

    if self.client then
        self.client:stop(true)
        self.client = nil
    end

    vim.api.nvim_clear_autocmds({ group = "lsp_bootstrap_" .. self.name })

    if self.linters then
        for _, linter in ipairs(self.linters) do
            linter:deinit()
        end

        self.linters = nil
    end

    require("lspconfig.configs")[self.name] = nil
    require("lspconfig")[self.name] = nil
end

--- Create a new instance
---@param name string
---@param config? ServerConfig
---@return Server|nil
function M.new(name, config)
    config = config or {}

    if config.enable == nil then
        config.enable = true
    end

    if not M.validate(name, config) then
        return
    end

    local ok, resp = pcall(require, "lspconfig.configs." .. name)
    if not ok and config.lspconfig then
        require("lspconfig.configs")[name] = vim.tbl_deep_extend(
            "keep",
            { default_config = {} },
            config.lspconfig
        )
    elseif ok then
        config.lspconfig = vim.tbl_deep_extend(
            "keep",
            config.lspconfig or {},
            resp.default_config
        )
    else
        utils.err(
            ("Server with name %s does not exist in lspconfig"):format(name)
        )
        return
    end

    local server = { name = name, config = config }

    if server.config.mason then
        local pkg = MasonPackage.new(server.config.mason)
        if pkg then
            server.mason = pkg
        end
    end

    return setmetatable(server, M)
end

return M