local severity = vim.diagnostic.severity
local function next_diagnostic(diagnostic_severity)
    return function()
        require('lspsaga.diagnostic'):goto_next({ severity = diagnostic_severity })
    end
end
local function prev_diagnostic(diagnostic_severity)
    return function()
        require('lspsaga.diagnostic'):goto_prev({ severity = diagnostic_severity })
    end
end
local function cursor_diagnostics()
    vim.diagnostic.open_float({
        scope = 'cursor',
        border = 'single',
    })
end

local keymaps = {
    { 'n', 'gd', '<cmd>Lspsaga goto_definition<cr>', { desc = '[G]oto [D]efinition' } },
    { 'n', 'gu', '<cmd>Lspsaga finder<cr>', { desc = '[G]oto [U]sages' } },
    { { 'n', 'i' }, '<C-p>', vim.lsp.buf.signature_help, { desc = 'Show [P]arameters' } },
    { 'n', 'K', '<cmd>Lspsaga hover_doc<cr>', { desc = 'Documentation' } },
    { 'n', 'R', '<cmd>Lspsaga rename<cr>', { desc = '[R]ename' } },
    { { 'n', 'i' }, '<M-Enter>', '<cmd>Lspsaga code_action<cr>', { desc = 'Code Actions' } },
    { 'n', '<leader>ca', '<cmd>Lspsaga code_action<cr><Esc>', { desc = '[C]ode [A]ctions' } },
    { 'n', '<leader>e', next_diagnostic(severity.ERROR), { desc = 'Goto [E]rror' } },
    { 'n', '<leader>E', prev_diagnostic(severity.ERROR), { desc = 'Goto [E]rror (prev)' } },
    { 'n', '<leader>w', next_diagnostic(severity.WARN), { desc = 'Goto [W]arning' } },
    { 'n', '<leader>W', prev_diagnostic(severity.WARN), { desc = 'Goto [W]arning (prev)' } },
    { 'n', '<leader>D', cursor_diagnostics, { desc = '[D]iagnostics under cursor' } },
}

for _, ft in ipairs({ 'c', 'h', 'cpp', 'hpp' }) do
    keymaps[ft] = {
        { 'n', 'H', '<cmd>ClangdSwitchSourceHeader<cr>', { desc = '[H]eader and Source Switcher' } },
        { 'n', 'K', '<cmd>lua require("pretty_hover").hover()<cr>', { desc = 'Documentation Hover' } },
    }
end

local function set_keymaps(tbl, bufnr)
    for _, keymap in ipairs(tbl) do
        local mode = keymap[1]
        local lhs = keymap[2]
        local rhs = keymap[3]
        local opts = keymap[4] or {}
        opts.buffer = bufnr
        vim.keymap.set(mode, lhs, rhs, opts)
    end
end

local M = {}

--- Registers LSP keymaps for the given buffer
---@param bufnr number: the id of the buffer
M.setup = function(bufnr)
    local filetype = vim.bo[bufnr].filetype
    set_keymaps(keymaps, bufnr)
    for ft, tbl in pairs(keymaps) do
        if type(ft) == 'number' or ft ~= filetype then
            goto continue
        end
        set_keymaps(tbl, bufnr)
        ::continue::
    end
end

return M