local h = require("test.git.helpers")
local t = require("test")

---Replicate the user's global cursor-restore autocmd. Scoped to a
---named augroup + cleanup so it doesn't leak between tests.
local function install_cursor_restore_autocmd()
    local group =
        vim.api.nvim_create_augroup("test.cursor_restore", { clear = true })
    vim.api.nvim_create_autocmd("BufReadPost", {
        group = group,
        pattern = "*",
        command = 'silent! normal! g`"zv',
    })
    t.defer(function()
        pcall(vim.api.nvim_del_augroup_by_name, "test.cursor_restore")
    end)
end

---@param sidebar_buf integer
---@param needle string
---@return integer?
local function find_line(sidebar_buf, needle)
    for i, l in ipairs(vim.api.nvim_buf_get_lines(sidebar_buf, 0, -1, false)) do
        if l:match(needle) then
            return i
        end
    end
end

---Find the gitstatus sidebar window in the current tabpage.
---@return integer? sidebar_buf
---@return integer? sidebar_win
local function find_sidebar()
    for _, w in ipairs(vim.api.nvim_tabpage_list_wins(0)) do
        local b = vim.api.nvim_win_get_buf(w)
        if vim.bo[b].filetype == "gitstatus" then
            return b, w
        end
    end
end

---Find a diff-role window in the given tabpage (or current).
---@param role "left"|"right"
---@param tab integer?
---@return integer?
local function find_diff_win(role, tab)
    for _, w in ipairs(vim.api.nvim_tabpage_list_wins(tab or 0)) do
        if vim.w[w].git_diff_role == role then
            return w
        end
    end
end

---@param file_path string
---@param committed_content string
---@param worktree_content string
---@return integer sidebar_win
---@return integer entry_line
local function setup_sidebar_with_unstaged_file(
    file_path,
    committed_content,
    worktree_content
)
    local repo = h.make_repo({ [file_path] = committed_content })
    t.write(repo, file_path, worktree_content)
    vim.cmd("cd " .. repo)

    require("git.status_view").open({ placement = "sidebar" })
    local sidebar_buf, sidebar_win = find_sidebar()
    assert(sidebar_buf, "sidebar buffer should exist")
    assert(sidebar_win, "sidebar window should exist")

    local r = assert(
        require("git.core.repo").find(vim.fn.getcwd()),
        "repo should resolve for the test worktree"
    )
    r:refresh()
    t.wait_for(function()
        return r.status and #r.status:rows("unstaged") > 0
    end, "git status to report unstaged changes")

    local entry_line = assert(
        find_line(sidebar_buf, vim.pesc(file_path) .. "$"),
        file_path .. " should appear in sidebar"
    )
    return sidebar_win, entry_line
end

t.test("stage with diff open: sidebar cursor stays put", function()
    install_cursor_restore_autocmd()
    local sidebar_win, line = setup_sidebar_with_unstaged_file(
        "zsh/rc",
        "ZSH=true\n",
        "ZSH=true\nmodified\n"
    )

    vim.api.nvim_set_current_win(sidebar_win)
    vim.api.nvim_win_set_cursor(sidebar_win, { line, 0 })

    t.press("<Tab>")
    t.wait_for(function()
        return find_diff_win("left") ~= nil
    end, "diff windows to appear")

    local r = assert(require("git.core.repo").find(vim.fn.getcwd()))
    vim.api.nvim_set_current_win(sidebar_win)
    t.press("s")
    t.wait_for(function()
        return #r.status:rows("staged") > 0
    end, "stage to propagate to repo state")

    t.eq(
        vim.api.nvim_win_get_cursor(sidebar_win),
        { line, 0 },
        "sidebar cursor should remain at the entry's original line"
    )
end)

t.test(
    "stage with diff open: diff foldmethod is preserved on refresh",
    function()
        local sidebar_win, line = setup_sidebar_with_unstaged_file(
            "zsh/rc",
            "# vim: set ft=zsh nowrap:\nZSH=true\n",
            "# vim: set ft=zsh nowrap:\nZSH=true\nmodified\n"
        )

        vim.api.nvim_set_current_win(sidebar_win)
        vim.api.nvim_win_set_cursor(sidebar_win, { line, 0 })

        t.press("<Tab>")
        t.wait_for(function()
            return find_diff_win("left") ~= nil
        end, "diff windows to appear")
        local left_win = assert(find_diff_win("left"))
        t.eq(
            vim.wo[left_win].foldmethod,
            "diff",
            "left diff foldmethod should be 'diff' after Tab"
        )

        local r = assert(require("git.core.repo").find(vim.fn.getcwd()))
        vim.api.nvim_set_current_win(sidebar_win)
        t.press("s")
        t.wait_for(function()
            return #r.status:rows("staged") > 0
        end, "stage to propagate to repo state")

        t.eq(
            vim.wo[left_win].foldmethod,
            "diff",
            "left diff foldmethod should still be 'diff' after stage refresh"
        )
    end
)

t.test(
    "<Tab> in a second tabpage opens the diff inside that tabpage",
    function()
        local sidebar_win, line =
            setup_sidebar_with_unstaged_file("foo.txt", "v1\n", "v2\n")
        local tab1 = vim.api.nvim_get_current_tabpage()

        -- First show diff in tab1, so state.diff_*_win point at tab1.
        vim.api.nvim_set_current_win(sidebar_win)
        vim.api.nvim_win_set_cursor(sidebar_win, { line, 0 })
        t.press("<Tab>")
        t.wait_for(function()
            return find_diff_win("left", tab1) ~= nil
        end, "diff windows in tab1 to appear")

        vim.cmd("tabnew")
        require("git.status_view").open({ placement = "sidebar" })
        local tab2 = vim.api.nvim_get_current_tabpage()
        t.truthy(tab2 ~= tab1, "tabnew should produce a distinct tabpage")

        local _, sidebar_win2 = find_sidebar()
        assert(sidebar_win2, "sidebar window should exist in tab2")
        vim.api.nvim_set_current_win(sidebar_win2)
        vim.api.nvim_win_set_cursor(sidebar_win2, { line, 0 })

        t.press("<Tab>")
        t.wait_for(function()
            return find_diff_win("left", tab2) ~= nil
        end, "diff windows in tab2 to appear")

        t.truthy(
            find_diff_win("right", tab2),
            "right diff window should be in tab2"
        )
    end
)

t.test("refresh on stage updates the index URI buffer's content", function()
    local sidebar_win, line =
        setup_sidebar_with_unstaged_file("foo.txt", "v1\n", "v2\n")

    vim.api.nvim_set_current_win(sidebar_win)
    vim.api.nvim_win_set_cursor(sidebar_win, { line, 0 })
    t.press("<Tab>")
    t.wait_for(function()
        return find_diff_win("left") ~= nil
    end, "diff windows to appear")

    local left_win = assert(find_diff_win("left"))
    local index_buf = vim.api.nvim_win_get_buf(left_win)
    t.eq(
        vim.api.nvim_buf_get_lines(index_buf, 0, -1, false),
        { "v1" },
        "index pane should initially show committed content"
    )

    vim.api.nvim_set_current_win(sidebar_win)
    t.press("s")
    t.wait_for(function()
        local first = vim.api.nvim_buf_get_lines(index_buf, 0, -1, false)[1]
        return first == "v2"
    end, "index pane to refresh to staged content")

    t.eq(
        vim.api.nvim_buf_get_lines(index_buf, 0, -1, false),
        { "v2" },
        "index pane should reflect staged content after refresh"
    )
end)