snacks.nvim/lua/snacks/picker/source/diff.lua

local M = {}

---@class snacks.picker.diff.Config: snacks.picker.proc.Config
---@field cmd? string optional since diff can be passed as string
---@field group? boolean Group hunks by file
---@field diff? string|number diff string or buffer number

---@class snacks.picker.diff.Hunk
---@field diff string[]
---@field line number

---@class snacks.picker.diff.Block
---@field type? "new"|"delete"|"rename"|"copy"|"mode"
---@field file string
---@field left? string
---@field right? string
---@field header string[]
---@field hunks snacks.picker.diff.Hunk[]

---@param opts? snacks.picker.diff.Config
---@type snacks.picker.finder
function M.diff(opts, ctx)
  opts = opts or {}
  local lines = {} ---@type string[]
  local finder ---@type snacks.picker.finder.result?

  do
    if opts.cmd then
      finder = require("snacks.picker.source.proc").proc(opts, ctx)
    else
      local diff = opts.diff
      if not diff and vim.bo.filetype == "diff" then
        diff = 0
      end
      if type(diff) == "number" then
        lines = vim.api.nvim_buf_get_lines(diff, 0, -1, false)
      elseif type(diff) == "string" then
        lines = vim.split(diff, "\n", { plain = true })
      else
        Snacks.notify.error("snacks.picker.diff: opts.diff must be a string or buffer number")
        return {}
      end
    end
  end

  local cwd = ctx.filter.cwd
  return function(cb)
    if finder then
      finder(function(proc_item)
        lines[#lines + 1] = proc_item.text
      end)
    end

    ---@param file string
    ---@param line? number
    ---@param diff string[]
    local function add(file, line, diff)
      line = line or 1
      cb({
        text = file .. ":" .. line,
        diff = table.concat(diff, "\n"),
        file = file,
        cwd = cwd,
        pos = { line, 0 },
      })
    end

    local blocks = M.parse(lines)
    for _, block in ipairs(blocks) do
      local diff = {} ---@type string[]
      for _, h in ipairs(block.hunks) do
        if opts.group then
          vim.list_extend(diff, h.diff)
        else
          add(block.file, h.line, vim.list_extend(vim.deepcopy(block.header), h.diff))
        end
      end
      if opts.group or #block.hunks == 0 then
        local line = block.hunks[1] and block.hunks[1].line or 1
        add(block.file, line, vim.list_extend(vim.deepcopy(block.header), diff))
      end
    end
  end
end

---@param lines string[]
function M.parse(lines)
  local hunk ---@type snacks.picker.diff.Hunk?
  local block ---@type snacks.picker.diff.Block?
  local ret = {} ---@type snacks.picker.diff.Block[]

  ---@param file? string
  ---@return string?
  local function norm(file)
    if file then
      file = file:gsub("\t.*$", "") -- remove tab and after
      file = file:gsub('^"(.-)"$', "%1") -- remove quotes
      if file == "/dev/null" then -- no file
        return
      end
      local prefix = { "a", "b", "i", "w", "c", "o", "old", "new" }
      for _, s in ipairs(prefix) do -- remove prefixes
        if file:sub(1, #s + 1) == s .. "/" then
          return file:sub(#s + 2)
        end
      end
      return file
    end
  end

  local function emit()
    if block and hunk then
      hunk = nil
    elseif not block then
      return
    end
    for _, line in ipairs(block.header) do
      if line:find("^%-%-%- ") then
        block.left = norm(line:sub(5))
      elseif line:find("^%+%+%+ ") then
        block.right = norm(line:sub(5))
      elseif line:find("^rename from") then
        block.type = "rename"
        block.left = norm(line:match("^rename from (.*)"))
      elseif line:find("^rename to") then
        block.type = "rename"
        block.right = norm(line:match("^rename to (.*)"))
      elseif line:find("^copy from") then
        block.type = "copy"
        block.left = norm(line:match("^copy from (.*)"))
      elseif line:find("^copy to") then
        block.type = "copy"
        block.right = norm(line:match("^copy to (.*)"))
      elseif line:find("^new file mode") then
        block.type = "new"
      elseif line:find("^deleted file mode") then
        block.type = "delete"
      elseif line:find("^old mode") or line:find("^new mode") then
        block.type = "mode"
      end
    end
    local first = block.header[1] or ""
    if not block.right and not block.left and first:find("^diff") then
      -- no left/right so for sure no rename.
      -- this means the diff header is for the same file
      if first:find("^diff %-%-cc") then
        block.left = norm(first:match("^diff %-%-cc (.+)$"))
        block.right = block.left
      else
        first = first:gsub("^diff ", ""):gsub("^%s*%-%S+%s*", "") --[[@as string]]
        local idx = 1
        while idx <= #first do
          local s = first:find(" ", idx, true)
          if not s then
            break
          end
          idx = s + 1
          local l = norm(first:sub(1, s - 1))
          local r = norm(first:sub(s + 1))
          if l == r then
            block.left = l
            block.right = r
            break
          end
        end
      end
    end
    block.file = block.right or block.left or block.file
    table.sort(block.hunks, function(a, b)
      return a.line < b.line
    end)
    ret[#ret + 1] = block
    block = nil
  end

  local with_diff_header = vim.trim(table.concat(lines, "\n")):find("^diff") ~= nil

  for _, text in ipairs(lines) do
    if not block and text:find("^%s*$") then
      -- Ignore empty lines before a diff block
    elseif text:find("^diff") or (not with_diff_header and text:find("^%-%-%- ") and (not block or hunk)) then
      emit()
      block = {
        file = "", --file or "unknown",
        header = { text },
        hunks = {},
      }
    elseif text:find("@@", 1, true) == 1 and block then
      -- Hunk header
      local line = 1
      if text:find("@@@", 1, true) == 1 then
        line = tonumber(text:match("^@@@ %-%d+,?%d* %-%d+,?%d* %+(%d+),?%d* @@@")) or 1
      else
        line = tonumber(text:match("^@@ %-%d+,?%d* %+(%d+),?%d* @@")) or 1
      end
      hunk = {
        line = line,
        diff = { text },
      }
      block.hunks[#block.hunks + 1] = hunk
    elseif hunk then
      -- Hunk body
      hunk.diff[#hunk.diff + 1] = text
    elseif block then
      block.header[#block.header + 1] = text
    else
      Snacks.notify.error("unexpected line: " .. text, { title = "Snacks Picker Diff" })
    end
  end
  emit()
  return ret
end

return M