local M = {}

local function get_current_time()
    return os.date("%H:%M")
end

local function get_active_task_line()
    local lines = vim.api.nvim_buf_get_lines(0, 0, -1, false)
    local active_lines = {}
    for i, line in ipairs(lines) do
        if line:match("#status/in%-progress") then
            table.insert(active_lines, {line = line, lnum = i})
        end
    end

    if #active_lines == 0 then
        print("No active task found (#status/in-progress).")
        return nil, "no_active"
    elseif #active_lines > 1 then
        print("Multiple active tasks found. Please ensure only one task is #status/in-progress.")
        return nil, "multiple_active"
    else
        return active_lines[1].line, active_lines[1].lnum
    end
end

function M.create_new_task()
    local desc = vim.fn.input("Task Description: ")
    if desc == '' then return end

    local project = vim.fn.input("Project (leave empty if none, e.g., '[[Project Name]]'): ")
    local priority_options = {"high", "medium", "low"}
    local priority_idx = vim.fn.inputlist("Priority:", priority_options)
    local priority = priority_options[tonumber(priority_idx)] or "medium"

    local category_options = {"work", "meeting", "learning", "journal", "focused-work", "break"}
    local category_idx = vim.fn.inputlist("Category:", category_options)
    local category = category_options[tonumber(category_idx)] or "work"

    local new_task_line = string.format("- [ ] %s %s #status/todo #priority/%s #%s",
                                        desc, project, priority, category)

    vim.api.nvim_put({new_task_line}, "l", true, true)
    print("New task created: " .. new_task_line)
end

function M.start_task()
    local current_line, lnum = get_active_task_line()
    if not current_line then return end

    local new_line = current_line
    local current_time = get_current_time()

    if new_line:match("start:: %d%d:%d%d") then
        print("Task already has a start time. Updating to current time.")
        new_line = new_line:gsub("start:: %d%d:%d%d", "start:: " .. current_time)
    else
        new_line = new_line .. " start:: " .. current_time
    end
    
    -- Clear end time if present when starting a task again
    new_line = new_line:gsub(" end:: %d%d:%d%d", "")

    vim.api.nvim_buf_set_lines(0, lnum - 1, lnum, false, {new_line})
    print("Task started/resumed: " .. current_time)
end

function M.stop_task()
    local current_line, lnum = get_active_task_line()
    if not current_line then return end

    local new_line = current_line
    local current_time = get_current_time()

    if new_line:match("end:: %d%d:%d%d") then
        print("Task already has an end time. Updating to current time.")
        new_line = new_line:gsub("end:: %d%d:%d%d", "end:: " .. current_time)
    else
        new_line = new_line .. " end:: " .. current_time
    end

    -- Option to change status to done
    local change_status = vim.fn.confirm("Change status to #status/done?", "&Yes\n&No", 2)
    if change_status == 1 then -- Yes
        new_line = new_line:gsub("#status/in%-progress", "#status/done")
    end

    vim.api.nvim_buf_set_lines(0, lnum - 1, lnum, false, {new_line})
    print("Task stopped: " .. current_time)
end

return M