-- This Module contains all of the code specific to the Delta reviewer.
local state    = require("gitlab.state")
local u        = require("gitlab.utils")

local M        = {
    bufnr = nil,
    tabnr = nil
}

-- Public Functions
-- These functions are exposed externally and are used
-- when the reviewer is consumed by other code. They must follow the specification
-- outlined in the reviewer/init.lua file
M.open         = function()
    vim.api.nvim_command(string.format("DiffviewOpen %s", state.INFO.target_branch))
    M.tabnr = vim.api.nvim_get_current_tabpage()
end

M.jump         = function(file_name, new_line, old_line)
    if M.tabnr == nil then
        vim.notify("Can't jump to Diffvew. Is it open?", vim.log.levels.ERROR)
        return
    end
    vim.api.nvim_set_current_tabpage(M.tabnr)
    vim.cmd("DiffviewFocusFiles")
    local view = require("diffview.lib").get_current_view()
    if view == nil then
        vim.notify("Could not find Diffview view", vim.log.levels.ERROR)
        return
    end
    local files = view.panel:ordered_file_list()
    local layout = view.cur_layout
    for _, file in ipairs(files) do
        if file.path == file_name then
            view:set_file(file)
            if new_line ~= nil then
                layout.b:focus()
                vim.api.nvim_win_set_cursor(0, { tonumber(new_line), 0 })
            elseif old_line ~= nil then
                layout.a:focus()
                vim.api.nvim_win_set_cursor(0, { tonumber(old_line), 0 })
            end
            break
        end
    end
end

M.get_location = function()
    if M.tabnr == nil then return nil, nil, "Diffview reviewer must be initialized first" end
    local bufnr = vim.api.nvim_get_current_buf()
    -- check if we are in the diffview tab
    local tabnr = vim.api.nvim_get_current_tabpage()
    if tabnr ~= M.tabnr then return nil, nil, "Line location can only be determined within reviewer window" end
    -- check if we are in the diffview buffer
    local view = require("diffview.lib").get_current_view()
    local layout = view.cur_layout
    local file_name = nil
    local current_line_changes = nil
    if layout.a.file.bufnr == bufnr then
        file_name = layout.a.file.path
        current_line_changes = { new_line = nil, old_line = vim.api.nvim_win_get_cursor(0)[1] }
        return file_name, current_line_changes
    elseif layout.b.file.bufnr == bufnr then
        file_name = layout.b.file.path
        current_line_changes = { new_line = vim.api.nvim_win_get_cursor(0)[1], old_line = nil }
        return file_name, current_line_changes
    end
    return nil, nil, "Line location can only be determined within reviewer window"
end

return M