local highlight = require("rc.highlight")
local line = require("rc.line")
local ui = require("rc.ui")

local M = {}

local normalize_path
do
    if package.config:sub(1, 1) == "\\" then
        ---@param s string
        function normalize_path(s)
            s = vim.fs.normalize(s)
            return s:sub(2, 3) == ":/" and ("%s%s"):format(s:sub(1, 1):upper(), s:sub(2)) or s
        end
    else
        ---@param s string
        function normalize_path(s)
            return vim.fs.normalize(s)
        end
    end
end

local replace_homedir
do
    local home = vim.uv.os_homedir()
    if home then
        home = normalize_path(home)
        ---@param s string
        function replace_homedir(s)
            return s:sub(1, home:len()) == home and ("~%s"):format(s:sub(home:len() + 1)) or s
        end
    else
        ---@param s string
        function replace_homedir(s)
            return s
        end
    end
end

---@param s string
---@param buf integer
local function replace_cwd(s, buf)
    local cwd = normalize_path(vim.fn.getcwd(vim.fn.bufwinnr(buf)))
    return s:sub(1, cwd:len()) == cwd and s:sub(cwd:len() + 2) or s
end

---@param buf integer
local function current_file(buf)
    return replace_homedir(replace_cwd(normalize_path(vim.api.nvim_buf_get_name(buf)), buf))
end

---@param buf number
local function diagnostics(buf)
    local severity = vim.diagnostic.severity
    local hl_map = {
        [severity.ERROR] = "DiagnosticError",
        [severity.WARN] = "DiagnosticWarn",
        [severity.INFO] = "DiagnosticInfo",
        [severity.HINT] = "DiagnosticHint",
    }
    local severities = {
        severity.HINT,
        severity.WARN,
        severity.ERROR,
    }
    local r = " "
    for _, s in pairs(severities) do
        local count = #vim.diagnostic.get(buf, { severity = s })
        if count == 0 then
            r = r .. line.with_hl("󱓼 ", "WinBar")
        else
            local level = math.min(20 + count * 8, 100)
            r = r
                .. line.with_hl(
                    "󱓻 ",
                    highlight.ensure("WinBar" .. hl_map[s] .. level, function()
                        return highlight.get("Whitespace"):mix(hl_map[s], level)
                    end)
                )
        end
    end
    return r
end

local function get_winbar(buf)
    local s = " " .. current_file(buf):gsub("/", ui.winbar_sep.path) .. "%=" .. diagnostics(buf)
    return s
end

function M.setup()
    vim.api.nvim_create_autocmd("DiagnosticChanged", {
        callback = function(cx)
            vim.api.nvim__redraw({ winbar = true, buf = cx.buf })
        end,
    })
    vim.api.nvim_create_autocmd("BufRead", {
        pattern = "*",
        callback = function(cx)
            vim.opt_local.winbar = line.as_opt(get_winbar, tostring(cx.buf))
        end,
    })
end

return M