const std = @import("std");
const input = @import("input.zig");
const leader_mod = @import("leader.zig");
const protocol = @import("protocol.zig");
const replay = @import("replay.zig");
const repo_mod = @import("repo.zig");
const session_mod = @import("session.zig");
const symbol_mod = @import("symbol.zig");

// First terminal thin client surface, scriptable for E2E-style tests.
// req: session/001, session/003, ui/001, coding/001, testing/001, testing/002

test {
    _ = Client;
}

pub const Error = error{
    ViewportTooSmall,
    InvalidResize,
    UnknownTraceEvent,
    ProtocolRejected,
    ClientQuit,
    NothingSaved,
};

pub const Viewport = struct {
    width: usize,
    height: usize,

    pub fn validate(self: Viewport) !void {
        if (self.width == 0 or self.height < 2) return Error.ViewportTooSmall;
    }
};

pub const RenderDiagnostics = struct {
    viewport_width: usize,
    viewport_height: usize,
    frame_bytes: usize,
    frame_lines: usize,
    max_line_cells: usize,
    clipped_sources: usize,
};

pub const RenderResult = struct {
    frame: []u8,
    diagnostics: RenderDiagnostics,
    warning: []u8,

    pub fn deinit(self: RenderResult, allocator: std.mem.Allocator) void {
        allocator.free(self.frame);
        allocator.free(self.warning);
    }
};

pub fn runTrace(allocator: std.mem.Allocator, viewport: Viewport, trace: []const u8) !TraceResult {
    var client = try Client.init(allocator, viewport);
    defer client.deinit();

    var lines = std.mem.splitScalar(u8, trace, '\n');
    while (lines.next()) |line| {
        if (line.len == 0) continue;
        try client.handleTraceLine(line);
    }

    const frame = try client.render(allocator);
    errdefer allocator.free(frame);
    const saved_bytes = if (client.saved_bytes) |bytes| try allocator.dupe(u8, bytes) else null;
    errdefer if (saved_bytes) |bytes| allocator.free(bytes);
    return .{ .frame = frame, .saved_bytes = saved_bytes, .quit = client.quit };
}

pub const TraceResult = struct {
    frame: []u8,
    saved_bytes: ?[]u8,
    quit: bool,

    pub fn deinit(self: TraceResult, allocator: std.mem.Allocator) void {
        allocator.free(self.frame);
        if (self.saved_bytes) |bytes| allocator.free(bytes);
    }
};

pub const Client = struct {
    allocator: std.mem.Allocator,
    session: session_mod.Session,
    leader: leader_mod.Leader,
    repo: repo_mod.Index,
    viewport: Viewport,
    saved_bytes: ?[]u8 = null,
    message: ?[]const u8 = null,
    quit: bool = false,

    pub fn init(allocator: std.mem.Allocator, viewport: Viewport) !Client {
        try viewport.validate();
        return .{
            .allocator = allocator,
            .session = session_mod.Session.init(allocator),
            .leader = leader_mod.Leader.init(allocator),
            .repo = repo_mod.Index.init(allocator),
            .viewport = viewport,
        };
    }

    pub fn deinit(self: *Client) void {
        if (self.saved_bytes) |bytes| self.allocator.free(bytes);
        self.repo.deinit();
        self.leader.deinit();
        self.session.deinit();
        self.* = undefined;
    }

    pub fn handleTraceLine(self: *Client, line: []const u8) !void {
        if (std.mem.eql(u8, line, "quit")) {
            self.quit = true;
            return;
        }
        if (self.quit) return Error.ClientQuit;

        if (std.mem.startsWith(u8, line, "key ")) return self.handleTraceKey(line[4..]);
        if (std.mem.startsWith(u8, line, "type ")) return self.handleInput(line[5..]);
        if (std.mem.startsWith(u8, line, "repo_gitignore ")) return self.repo.addIgnorePattern(line[15..]);
        if (std.mem.startsWith(u8, line, "repo_file ")) return self.addRepoFile(line[10..]);
        if (std.mem.eql(u8, line, "file_picker")) return self.openRepoList("files", false, false);
        if (std.mem.eql(u8, line, "file_picker all")) return self.openRepoList("files", false, true);
        if (std.mem.eql(u8, line, "file_tree")) return self.openRepoList("tree", true, false);
        if (std.mem.eql(u8, line, "file_tree all")) return self.openRepoList("tree", true, true);
        if (std.mem.eql(u8, line, "file_open_selected")) return self.openSelectedRepoFile();
        if (std.mem.startsWith(u8, line, "panel_open ")) return self.applyProtocolCommand(line);
        if (std.mem.startsWith(u8, line, "list_open ")) return self.applyProtocolCommand(line);
        if (std.mem.startsWith(u8, line, "list_filter ")) return self.applyProtocolCommand(line);
        if (std.mem.startsWith(u8, line, "message ")) {
            self.message = line[8..];
            return;
        }
        if (std.mem.eql(u8, line, "list_down")) return self.applyProtocol("command list_down");
        if (std.mem.eql(u8, line, "list_up")) return self.applyProtocol("command list_up");
        if (std.mem.eql(u8, line, "list_select")) return self.applyProtocol("command list_select");
        if (std.mem.eql(u8, line, "list_cancel")) return self.applyProtocol("command list_cancel");
        if (std.mem.eql(u8, line, "panel_close")) return self.applyProtocol("command panel_close");
        if (std.mem.eql(u8, line, "panel_next")) return self.applyProtocol("command panel_next");
        if (std.mem.eql(u8, line, "panel_prev")) return self.applyProtocol("command panel_prev");
        if (std.mem.startsWith(u8, line, "open ")) return self.applyProtocol(line);
        if (std.mem.startsWith(u8, line, "insert ")) return self.applyProtocolCommand(line);
        if (std.mem.eql(u8, line, "left")) return self.applyProtocol("command move_left");
        if (std.mem.eql(u8, line, "right")) return self.applyProtocol("command move_right");
        if (std.mem.eql(u8, line, "backspace")) return self.applyProtocol("command delete_backward");
        if (std.mem.eql(u8, line, "save")) return self.save();
        if (std.mem.startsWith(u8, line, "resize ")) return self.resize(line[7..]);
        if (std.mem.eql(u8, line, "render")) return;

        return Error.UnknownTraceEvent;
    }

    pub fn render(self: *const Client, allocator: std.mem.Allocator) ![]u8 {
        try self.viewport.validate();
        const snap = try self.session.snapshot();
        if (snap.active_panel_title != null) return self.renderPanel(allocator, snap);
        return self.renderEditor(allocator, snap);
    }

    pub fn renderWithDiagnostics(self: *const Client, allocator: std.mem.Allocator) !RenderResult {
        const frame = try self.render(allocator);
        errdefer allocator.free(frame);
        var diagnostics = diagnoseFrame(self.viewport, frame);
        diagnostics.clipped_sources = try self.countClippedSources(allocator);
        const warning = try renderWarningAlloc(allocator, diagnostics);
        return .{ .frame = frame, .diagnostics = diagnostics, .warning = warning };
    }

    fn renderEditor(self: *const Client, allocator: std.mem.Allocator, snap: session_mod.Snapshot) ![]u8 {
        var out = std.ArrayList(u8).empty;
        errdefer out.deinit(allocator);

        const max_body_lines = self.viewport.height - 1;
        const cursor_line = lineIndexAt(snap.bytes, snap.cursor_byte);
        const cursor_col = columnAt(snap.bytes, snap.cursor_byte);
        var visible_line_index: usize = 0;
        var body_lines_used: usize = 0;
        var line_iter = std.mem.splitScalar(u8, snap.bytes, '\n');
        while (line_iter.next()) |line| : (visible_line_index += 1) {
            if (body_lines_used >= max_body_lines) break;
            try appendVisibleCells(allocator, &out, line, self.viewport.width);
            try out.append(allocator, '\n');
            body_lines_used += 1;

            if (visible_line_index == cursor_line and body_lines_used < max_body_lines) {
                try appendCursorLine(allocator, &out, @min(cursor_col, self.viewport.width - 1), self.viewport.width);
                body_lines_used += 1;
            }
        }
        while (body_lines_used < max_body_lines) : (body_lines_used += 1) {
            try out.append(allocator, '~');
            try out.append(allocator, '\n');
        }

        const leader_status = self.leader.status();
        const status = if (self.message) |message|
            try std.fmt.allocPrint(allocator, "{s}", .{message})
        else if (leader_status.len != 0)
            try std.fmt.allocPrint(
                allocator,
                "{s}{s}{s}",
                .{ leader_status, if (self.leader.promptText().len > 0) ": " else "", self.leader.promptText() },
            )
        else
            try std.fmt.allocPrint(
                allocator,
                "mim row={d} col={d} bytes={d}{s}",
                .{ cursor_line + 1, cursor_col + 1, snap.bytes.len, if (self.quit) " quit" else "" },
            );
        defer allocator.free(status);
        try appendVisibleCells(allocator, &out, status, self.viewport.width);
        return out.toOwnedSlice(allocator);
    }

    fn renderPanel(self: *const Client, allocator: std.mem.Allocator, snap: session_mod.Snapshot) ![]u8 {
        var out = std.ArrayList(u8).empty;
        errdefer out.deinit(allocator);
        const max_body_lines = self.viewport.height - 1;
        var body_lines_used: usize = 0;

        const path = try self.session.panelPathAlloc(allocator);
        defer allocator.free(path);
        const header = try std.fmt.allocPrint(allocator, "panel {s}", .{path});
        defer allocator.free(header);
        try appendVisibleCells(allocator, &out, header, self.viewport.width);
        try out.append(allocator, '\n');
        body_lines_used += 1;

        const remaining_rows = max_body_lines - body_lines_used;
        const rows = self.session.activeListRowsAlloc(allocator, remaining_rows) catch null;
        if (rows) |list_rows| {
            defer {
                for (list_rows) |row| allocator.free(row);
                allocator.free(list_rows);
            }
            for (list_rows) |row| {
                if (body_lines_used >= max_body_lines) break;
                try appendVisibleCells(allocator, &out, row, self.viewport.width);
                try out.append(allocator, '\n');
                body_lines_used += 1;
            }
        } else if (body_lines_used < max_body_lines) {
            const title = snap.active_panel_title.?;
            const detail = try std.fmt.allocPrint(allocator, "{s}: no content yet", .{title});
            defer allocator.free(detail);
            try appendVisibleCells(allocator, &out, detail, self.viewport.width);
            try out.append(allocator, '\n');
            body_lines_used += 1;
        }
        while (body_lines_used < max_body_lines) : (body_lines_used += 1) {
            try out.append(allocator, '~');
            try out.append(allocator, '\n');
        }

        const status = if (self.message) |message|
            try std.fmt.allocPrint(allocator, "{s}", .{message})
        else
            try std.fmt.allocPrint(
                allocator,
                "panel {d}/{d}  x close",
                .{ snap.active_panel_index.? + 1, snap.panel_depth },
            );
        defer allocator.free(status);
        try appendVisibleCells(allocator, &out, status, self.viewport.width);
        return out.toOwnedSlice(allocator);
    }

    pub fn handleInput(self: *Client, raw: []const u8) !void {
        if (self.quit) return Error.ClientQuit;
        const event = input.normalize(raw);
        if (self.leader.capturesInput() or isLeaderTrigger(event)) {
            const action = try self.leader.handleEvent(event);
            defer action.deinit(self.allocator);
            try self.applyLeaderAction(action);
            return;
        }

        _ = try self.leader.handleEvent(event);
        try self.applyNormalInput(event);
    }

    pub fn saved(self: *const Client) ![]const u8 {
        return self.saved_bytes orelse Error.NothingSaved;
    }

    fn addRepoFile(self: *Client, payload: []const u8) !void {
        const separator = std.mem.indexOfScalar(u8, payload, '=') orelse return repo_mod.Error.InvalidPath;
        try self.repo.addFile(payload[0..separator], payload[separator + 1 ..]);
    }

    fn openRepoList(self: *Client, title: []const u8, tree: bool, include_ignored: bool) !void {
        const items = if (tree)
            try self.repo.treeItemsAlloc(self.allocator, include_ignored)
        else
            try self.repo.pickerItemsAlloc(self.allocator, include_ignored);
        defer self.allocator.free(items);
        try self.session.openListPanel(title, items);
        self.message = null;
    }

    fn openSelectedRepoFile(self: *Client) !void {
        const selected = self.session.selectListPanel() catch return Error.ProtocolRejected;
        const content = self.repo.content(selected) catch return Error.ProtocolRejected;
        try self.session.openFixture(content);
        try self.session.closePanel();
        self.message = null;
    }

    fn handleTraceKey(self: *Client, key_name: []const u8) !void {
        if (std.mem.eql(u8, key_name, "space")) return self.handleInput(" ");
        if (std.mem.eql(u8, key_name, "enter")) return self.handleInput("\r");
        if (std.mem.eql(u8, key_name, "backspace")) return self.handleInput("\x7f");
        if (std.mem.eql(u8, key_name, "escape")) return self.handleInput("\x1b");
        if (std.mem.eql(u8, key_name, "left")) return self.handleInput("\x1b[D");
        if (std.mem.eql(u8, key_name, "right")) return self.handleInput("\x1b[C");
        if (key_name.len == 1) return self.handleInput(key_name);
        return Error.UnknownTraceEvent;
    }

    fn isLeaderTrigger(event: input.Event) bool {
        return switch (event) {
            .key => |key| key == .space,
            else => false,
        };
    }

    fn applyNormalInput(self: *Client, event: input.Event) !void {
        switch (event) {
            .text => |text| {
                const line = try std.fmt.allocPrint(self.allocator, "insert {s}", .{text});
                defer self.allocator.free(line);
                try self.applyProtocolCommand(line);
            },
            .key => |key| switch (key) {
                .backspace => try self.applyProtocol("command delete_backward"),
                .arrow_left => try self.applyProtocol("command move_left"),
                .arrow_right => try self.applyProtocol("command move_right"),
                else => {},
            },
            .unknown => {},
        }
    }

    fn applyLeaderAction(self: *Client, action: leader_mod.Action) !void {
        switch (action) {
            .none => {},
            .save => try self.save(),
            .quit => self.quit = true,
            .open => |path| {
                const line = try std.fmt.allocPrint(self.allocator, "open {s}", .{path});
                defer self.allocator.free(line);
                try self.applyProtocol(line);
            },
            .symbol => |symbol| try self.applyProtocol(symbol_mod.protocolCommand(symbol)),
            .not_built => {},
        }
    }

    fn applyProtocolCommand(self: *Client, line: []const u8) !void {
        const command = try std.fmt.allocPrint(self.allocator, "command {s}", .{line});
        defer self.allocator.free(command);
        try self.applyProtocol(command);
    }

    fn applyProtocol(self: *Client, line: []const u8) !void {
        const response = try protocol.handleLine(self.allocator, &self.session, line);
        defer self.allocator.free(response);
        if (std.mem.startsWith(u8, response, "err ")) {
            self.message = protocolErrorMessage(response);
            return Error.ProtocolRejected;
        }
        self.message = null;
    }

    fn protocolErrorMessage(response: []const u8) []const u8 {
        if (std.mem.indexOf(u8, response, "invalid panel title") != null) return "error: invalid panel title";
        if (std.mem.indexOf(u8, response, "no panel open") != null) return "error: no panel open";
        if (std.mem.indexOf(u8, response, "invalid list") != null) return "error: invalid list";
        if (std.mem.indexOf(u8, response, "active panel is not list") != null) return "error: active panel is not list";
        return "error: command failed";
    }

    fn resize(self: *Client, payload: []const u8) !void {
        const x = std.mem.indexOfScalar(u8, payload, 'x') orelse return Error.InvalidResize;
        const width = std.fmt.parseUnsigned(usize, payload[0..x], 10) catch return Error.InvalidResize;
        const height = std.fmt.parseUnsigned(usize, payload[x + 1 ..], 10) catch return Error.InvalidResize;
        const viewport = Viewport{ .width = width, .height = height };
        try viewport.validate();
        self.viewport = viewport;
    }

    fn save(self: *Client) !void {
        const snap = try self.session.snapshot();
        const copy = try self.allocator.dupe(u8, snap.bytes);
        if (self.saved_bytes) |old| self.allocator.free(old);
        self.saved_bytes = copy;
        self.message = "saved";
    }

    fn countClippedSources(self: *const Client, allocator: std.mem.Allocator) !usize {
        const snap = try self.session.snapshot();
        var clipped: usize = 0;
        if (snap.active_panel_title == null) {
            var line_iter = std.mem.splitScalar(u8, snap.bytes, '\n');
            while (line_iter.next()) |line| {
                if (session_mod.cellWidth(line) > self.viewport.width) clipped += 1;
            }
            if (self.message) |message| {
                if (session_mod.cellWidth(message) > self.viewport.width) clipped += 1;
            }
            return clipped;
        }

        const path = try self.session.panelPathAlloc(allocator);
        defer allocator.free(path);
        const header = try std.fmt.allocPrint(allocator, "panel {s}", .{path});
        defer allocator.free(header);
        if (session_mod.cellWidth(header) > self.viewport.width) clipped += 1;

        const remaining_rows = self.viewport.height - 1;
        const rows = self.session.activeListRowsAlloc(allocator, remaining_rows) catch null;
        if (rows) |list_rows| {
            defer {
                for (list_rows) |row| allocator.free(row);
                allocator.free(list_rows);
            }
            for (list_rows) |row| {
                if (session_mod.cellWidth(row) > self.viewport.width) clipped += 1;
            }
        } else if (snap.active_panel_title) |title| {
            const detail = try std.fmt.allocPrint(allocator, "{s}: no content yet", .{title});
            defer allocator.free(detail);
            if (session_mod.cellWidth(detail) > self.viewport.width) clipped += 1;
        }

        const status = if (self.message) |message|
            try std.fmt.allocPrint(allocator, "{s}", .{message})
        else
            try std.fmt.allocPrint(allocator, "panel {d}/{d}  x close", .{ snap.active_panel_index.? + 1, snap.panel_depth });
        defer allocator.free(status);
        if (session_mod.cellWidth(status) > self.viewport.width) clipped += 1;
        return clipped;
    }
};

fn appendVisibleCells(allocator: std.mem.Allocator, out: *std.ArrayList(u8), bytes: []const u8, max_cells: usize) !void {
    var i: usize = 0;
    while (i < bytes.len) {
        const len = std.unicode.utf8ByteSequenceLength(bytes[i]) catch 1;
        const end = @min(bytes.len, i + len);
        const next = bytes[0..end];
        if (session_mod.cellWidth(next) > max_cells) break;
        try out.appendSlice(allocator, bytes[i..end]);
        i = end;
    }
}

fn appendCursorLine(allocator: std.mem.Allocator, out: *std.ArrayList(u8), cursor_col: usize, max_cells: usize) !void {
    var i: usize = 0;
    while (i < cursor_col and i + 1 < max_cells) : (i += 1) try out.append(allocator, ' ');
    try out.append(allocator, '^');
    try out.append(allocator, '\n');
}

fn lineIndexAt(bytes: []const u8, cursor_byte: usize) usize {
    var line: usize = 0;
    for (bytes[0..@min(cursor_byte, bytes.len)]) |byte| {
        if (byte == '\n') line += 1;
    }
    return line;
}

fn columnAt(bytes: []const u8, cursor_byte: usize) usize {
    const prefix = bytes[0..@min(cursor_byte, bytes.len)];
    const line_start = if (std.mem.lastIndexOfScalar(u8, prefix, '\n')) |idx| idx + 1 else 0;
    return session_mod.cellWidth(prefix[line_start..]);
}

fn diagnoseFrame(viewport: Viewport, frame: []const u8) RenderDiagnostics {
    var diagnostics = RenderDiagnostics{
        .viewport_width = viewport.width,
        .viewport_height = viewport.height,
        .frame_bytes = frame.len,
        .frame_lines = 0,
        .max_line_cells = 0,
        .clipped_sources = 0,
    };
    var lines = std.mem.splitScalar(u8, frame, '\n');
    while (lines.next()) |line| {
        diagnostics.frame_lines += 1;
        diagnostics.max_line_cells = @max(diagnostics.max_line_cells, session_mod.cellWidth(line));
    }
    return diagnostics;
}

fn renderWarningAlloc(allocator: std.mem.Allocator, diagnostics: RenderDiagnostics) ![]u8 {
    if (diagnostics.frame_lines != diagnostics.viewport_height) {
        return std.fmt.allocPrint(
            allocator,
            "render warning: expected {d} lines, rendered {d}",
            .{ diagnostics.viewport_height, diagnostics.frame_lines },
        );
    }
    if (diagnostics.max_line_cells > diagnostics.viewport_width) {
        return std.fmt.allocPrint(
            allocator,
            "render warning: line width {d} exceeds viewport {d}",
            .{ diagnostics.max_line_cells, diagnostics.viewport_width },
        );
    }
    if (diagnostics.clipped_sources > 0) {
        return std.fmt.allocPrint(
            allocator,
            "render warning: clipped {d} source line(s) to fit {d} columns",
            .{ diagnostics.clipped_sources, diagnostics.viewport_width },
        );
    }
    return std.fmt.allocPrint(
        allocator,
        "render ok: {d} lines, {d} bytes, max {d}/{d} cells",
        .{ diagnostics.frame_lines, diagnostics.frame_bytes, diagnostics.max_line_cells, diagnostics.viewport_width },
    );
}

fn assertLinesFit(frame: []const u8, width: usize) !void {
    var lines = std.mem.splitScalar(u8, frame, '\n');
    while (lines.next()) |line| {
        try std.testing.expect(session_mod.cellWidth(line) <= width);
    }
}

test "regular: scripted narrow terminal trace edits saves exits and replays saved bytes" {
    const trace =
        \\open abc
        \\right
        \\insert é
        \\save
        \\quit
        \\
    ;
    const result = try runTrace(std.testing.allocator, .{ .width = 12, .height = 4 }, trace);
    defer result.deinit(std.testing.allocator);
    try std.testing.expect(result.quit);
    try std.testing.expect(std.mem.indexOf(u8, result.frame, "aébc") != null);
    try assertLinesFit(result.frame, 12);
    try std.testing.expectEqualStrings("aébc", result.saved_bytes.?);

    const recording =
        \\protocol open abc
        \\protocol command move_right
        \\input insert é
        \\save aébc
        \\
    ;
    const replay_result = try replay.replayText(std.testing.allocator, recording);
    defer replay_result.deinit(std.testing.allocator);
    switch (replay_result) {
        .ok => {},
        .diverged => return error.ExpectedReplayOk,
    }
}

test "regular: backspace deletes whole UTF-8 codepoint through terminal client" {
    var client = try Client.init(std.testing.allocator, .{ .width = 10, .height = 3 });
    defer client.deinit();

    try client.handleTraceLine("open aéb");
    try client.handleTraceLine("right");
    try client.handleTraceLine("right");
    try client.handleTraceLine("backspace");
    try client.handleTraceLine("save");

    try std.testing.expectEqualStrings("ab", try client.saved());
}

test "regular: resize changes render width without changing buffer bytes" {
    var client = try Client.init(std.testing.allocator, .{ .width = 8, .height = 3 });
    defer client.deinit();

    try client.handleTraceLine("open abcdefghijk");
    try client.handleTraceLine("resize 5x3");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);

    try assertLinesFit(frame, 5);
    try client.handleTraceLine("save");
    try std.testing.expectEqualStrings("abcdefghijk", try client.saved());
}

test "adversarial: tiny or malformed resize is rejected" {
    var client = try Client.init(std.testing.allocator, .{ .width = 4, .height = 3 });
    defer client.deinit();
    try client.handleTraceLine("open abc");

    try std.testing.expectError(Error.ViewportTooSmall, client.handleTraceLine("resize 0x3"));
    try std.testing.expectError(Error.InvalidResize, client.handleTraceLine("resize phone"));
}

test "adversarial: invalid UTF-8 insertion is rejected and previous bytes can still save" {
    var client = try Client.init(std.testing.allocator, .{ .width = 10, .height = 3 });
    defer client.deinit();
    try client.handleTraceLine("open safe");

    const bad = [_]u8{ 'i', 'n', 's', 'e', 'r', 't', ' ', 0xc3, 0x28 };
    try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine(&bad));
    try client.handleTraceLine("save");
    try std.testing.expectEqualStrings("safe", try client.saved());
}

test "adversarial: quit prevents further edits" {
    var client = try Client.init(std.testing.allocator, .{ .width = 10, .height = 3 });
    defer client.deinit();
    try client.handleTraceLine("open abc");
    try client.handleTraceLine("quit");

    try std.testing.expectError(Error.ClientQuit, client.handleTraceLine("insert x"));
}

test "regular: leader rail is visible in terminal render and dispatches save" {
    var client = try Client.init(std.testing.allocator, .{ .width = 64, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open abc");
    try client.handleTraceLine("key space");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "leader: s save") != null);

    try client.handleTraceLine("key s");
    try std.testing.expectEqualStrings("abc", try client.saved());
}

test "regular: leader rail dispatches quit" {
    var client = try Client.init(std.testing.allocator, .{ .width = 40, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open abc");
    try client.handleTraceLine("key space");
    try client.handleTraceLine("key q");
    try std.testing.expect(client.quit);
    try std.testing.expectError(Error.ClientQuit, client.handleTraceLine("insert x"));
}

test "regular: leader open prompt opens typed UTF-8 payload" {
    var client = try Client.init(std.testing.allocator, .{ .width = 64, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open old");
    try client.handleTraceLine("key space");
    try client.handleTraceLine("key o");
    try client.handleTraceLine("type café.zig");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "café.zig") != null);

    try client.handleTraceLine("key enter");
    try client.handleTraceLine("key space");
    try client.handleTraceLine("key s");
    try std.testing.expectEqualStrings("café.zig", try client.saved());
}

test "regular: leader search and panel-close entries recover as not-built messages" {
    var client = try Client.init(std.testing.allocator, .{ .width = 64, .height = 4 });
    defer client.deinit();
    try client.handleTraceLine("open abc");

    try client.handleTraceLine("key space");
    try client.handleTraceLine("key /");
    const search_frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(search_frame);
    try std.testing.expect(std.mem.indexOf(u8, search_frame, "search is not built") != null);

    try client.handleTraceLine("key space");
    try client.handleTraceLine("key x");
    const close_frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(close_frame);
    try std.testing.expect(std.mem.indexOf(u8, close_frame, "panel close is not built") != null);
}

test "adversarial: unknown leader input recovers without saving or quitting" {
    var client = try Client.init(std.testing.allocator, .{ .width = 48, .height = 4 });
    defer client.deinit();
    try client.handleTraceLine("open abc");

    try client.handleTraceLine("key space");
    try client.handleTraceLine("key ?");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "unknown leader key") != null);
    try std.testing.expect(!client.quit);
    try std.testing.expectError(Error.NothingSaved, client.saved());
}

fn expectSymbolTrace(symbol_key: []const u8, expected_bytes: []const u8, expected_cursor_byte: usize) !void {
    var client = try Client.init(std.testing.allocator, .{ .width = 64, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open base");
    try client.handleTraceLine("key space");
    try client.handleTraceLine("key p");
    const rail = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(rail);
    try std.testing.expect(std.mem.indexOf(u8, rail, "symbols:") != null);

    const line = try std.fmt.allocPrint(std.testing.allocator, "key {s}", .{symbol_key});
    defer std.testing.allocator.free(line);
    try client.handleTraceLine(line);

    const snap = try client.session.snapshot();
    try std.testing.expectEqualStrings(expected_bytes, snap.bytes);
    try std.testing.expectEqual(expected_cursor_byte, snap.cursor_byte);
}

test "regular: symbol rail inserts paired braces brackets parens and quotes with cursor inside" {
    try expectSymbolTrace("p", "()base", 1);
    try expectSymbolTrace("b", "[]base", 1);
    try expectSymbolTrace("c", "{}base", 1);
    try expectSymbolTrace("q", "\"\"base", 1);
    try expectSymbolTrace("e", "''base", 1);
    try expectSymbolTrace("t", "``base", 1);
}

test "regular: symbol rail inserts slash pipe and underscore as single symbols" {
    try expectSymbolTrace("s", "/base", 1);
    try expectSymbolTrace("v", "|base", 1);
    try expectSymbolTrace("u", "_base", 1);
}

test "adversarial: unknown symbol key does not mutate the buffer" {
    var client = try Client.init(std.testing.allocator, .{ .width = 64, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open base");
    try client.handleTraceLine("key space");
    try client.handleTraceLine("key p");
    try client.handleTraceLine("key ?");

    const snap = try client.session.snapshot();
    try std.testing.expectEqualStrings("base", snap.bytes);
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "unknown symbol key") != null);
}

test "regular: narrow terminal renders active panel instead of editor and returns cleanly" {
    var client = try Client.init(std.testing.allocator, .{ .width = 20, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open editor-text");
    try client.handleTraceLine("panel_open files");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "panel [files]") != null);
    try std.testing.expect(std.mem.indexOf(u8, frame, "editor-text") == null);
    try assertLinesFit(frame, 20);

    try client.handleTraceLine("panel_close");
    const editor_frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(editor_frame);
    try std.testing.expect(std.mem.indexOf(u8, editor_frame, "editor-text") != null);
    try std.testing.expect(std.mem.indexOf(u8, editor_frame, "panel [files]") == null);
    try assertLinesFit(editor_frame, 20);
}

test "regular: nested panel breadcrumbs render on narrow terminal without overflow" {
    var client = try Client.init(std.testing.allocator, .{ .width = 18, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open abc");
    try client.handleTraceLine("panel_open files");
    try client.handleTraceLine("panel_open diagnostics");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "panel files>") != null);
    try std.testing.expect(std.mem.indexOf(u8, frame, "[diagnostics]") == null);
    try assertLinesFit(frame, 18);

    try client.handleTraceLine("panel_prev");
    const previous_frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(previous_frame);
    try std.testing.expect(std.mem.indexOf(u8, previous_frame, "panel [files]") != null);
    try assertLinesFit(previous_frame, 18);
}

test "adversarial: invalid panel title and empty close recover without changing editor render" {
    var client = try Client.init(std.testing.allocator, .{ .width = 16, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open abc");
    try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine("panel_open bad title"));
    try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine("panel_close"));
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "abc") != null);
    try assertLinesFit(frame, 16);
}

test "regular: list panel filters moves selects and renders rows" {
    var client = try Client.init(std.testing.allocator, .{ .width = 32, .height = 5 });
    defer client.deinit();

    try client.handleTraceLine("list_open files src/main.zig|src/panel.zig|README.md");
    try client.handleTraceLine("list_filter src");
    try client.handleTraceLine("list_down");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "panel [files]") != null);
    try std.testing.expect(std.mem.indexOf(u8, frame, "> src/panel.zig") != null);
    try assertLinesFit(frame, 32);

    try client.handleTraceLine("list_select");
    const summary = try client.session.panelSummaryAlloc(std.testing.allocator);
    defer std.testing.allocator.free(summary);
    try std.testing.expectEqualStrings("list:filter=src,cursor=1,visible=2,selected=src/panel.zig", summary);
}

test "regular: list cancel returns to previous editor surface" {
    var client = try Client.init(std.testing.allocator, .{ .width = 24, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open abc");
    try client.handleTraceLine("list_open files a.zig|b.zig");
    try client.handleTraceLine("list_cancel");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "abc") != null);
    try std.testing.expect(std.mem.indexOf(u8, frame, "panel") == null);
}

test "adversarial: list no-match state and invalid actions recover" {
    var client = try Client.init(std.testing.allocator, .{ .width = 24, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("list_open files a.zig|b.zig");
    try client.handleTraceLine("list_filter none");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "no matches") != null);
    try assertLinesFit(frame, 24);

    try client.handleTraceLine("list_cancel");
    try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine("list_down"));
}

test "regular: save status appears near editor status line" {
    var client = try Client.init(std.testing.allocator, .{ .width = 20, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open abc");
    try client.handleTraceLine("key space");
    try client.handleTraceLine("key s");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "saved") != null);
    try assertLinesFit(frame, 20);
}

test "regular: empty generic panel shows local empty state" {
    var client = try Client.init(std.testing.allocator, .{ .width = 22, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("panel_open help");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "help: no content yet") != null);
    try assertLinesFit(frame, 22);
}

test "adversarial: protocol errors render recoverable local message" {
    var client = try Client.init(std.testing.allocator, .{ .width = 24, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open abc");
    try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine("panel_open bad title"));
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "error: invalid panel") != null);
    try assertLinesFit(frame, 24);
}

test "adversarial: long feedback messages are clipped to viewport width" {
    var client = try Client.init(std.testing.allocator, .{ .width = 16, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open abc");
    try client.handleTraceLine("message this-message-is-way-too-long-for-the-phone-width");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try assertLinesFit(frame, 16);
    try std.testing.expect(std.mem.indexOf(u8, frame, "this-message-is-") != null);
    try std.testing.expect(std.mem.indexOf(u8, frame, "phone-width") == null);
}

test "regular: render diagnostics report ok for representative narrow editor frame" {
    var client = try Client.init(std.testing.allocator, .{ .width = 32, .height = 5 });
    defer client.deinit();

    try client.handleTraceLine("open fn main() {}");
    try client.handleTraceLine("key space");
    try client.handleTraceLine("key p");
    try client.handleTraceLine("key c");
    try client.handleTraceLine("type x");
    const result = try client.renderWithDiagnostics(std.testing.allocator);
    defer result.deinit(std.testing.allocator);

    try std.testing.expectEqual(@as(usize, 5), result.diagnostics.frame_lines);
    try std.testing.expect(result.diagnostics.frame_bytes <= 32 * 5 * 4);
    try std.testing.expect(result.diagnostics.max_line_cells <= 32);
    try std.testing.expectEqual(@as(usize, 0), result.diagnostics.clipped_sources);
    try std.testing.expect(std.mem.indexOf(u8, result.warning, "render ok") != null);
}

test "regular: render diagnostics report ok for representative list panel frame" {
    var client = try Client.init(std.testing.allocator, .{ .width = 36, .height = 5 });
    defer client.deinit();

    try client.handleTraceLine("list_open files src/main.zig|src/panel.zig|README.md");
    try client.handleTraceLine("list_filter src");
    try client.handleTraceLine("list_down");
    const result = try client.renderWithDiagnostics(std.testing.allocator);
    defer result.deinit(std.testing.allocator);

    try std.testing.expectEqual(@as(usize, 5), result.diagnostics.frame_lines);
    try std.testing.expect(result.diagnostics.frame_bytes <= 36 * 5 * 4);
    try std.testing.expect(result.diagnostics.max_line_cells <= 36);
    try std.testing.expectEqual(@as(usize, 0), result.diagnostics.clipped_sources);
    try std.testing.expect(std.mem.indexOf(u8, result.warning, "render ok") != null);
}

test "adversarial: render diagnostics name clipped editor sources" {
    var client = try Client.init(std.testing.allocator, .{ .width = 12, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("open this-line-is-far-too-long-for-phone");
    const result = try client.renderWithDiagnostics(std.testing.allocator);
    defer result.deinit(std.testing.allocator);

    try std.testing.expectEqual(@as(usize, 4), result.diagnostics.frame_lines);
    try std.testing.expect(result.diagnostics.max_line_cells <= 12);
    try std.testing.expect(result.diagnostics.clipped_sources >= 1);
    try std.testing.expect(std.mem.indexOf(u8, result.warning, "clipped") != null);
    try std.testing.expect(std.mem.indexOf(u8, result.warning, "12 columns") != null);
}

test "adversarial: render diagnostics name clipped panel sources" {
    var client = try Client.init(std.testing.allocator, .{ .width = 14, .height = 4 });
    defer client.deinit();

    try client.handleTraceLine("list_open files src/very-long-mobile-render-file-name.zig|b.zig");
    const result = try client.renderWithDiagnostics(std.testing.allocator);
    defer result.deinit(std.testing.allocator);

    try std.testing.expectEqual(@as(usize, 4), result.diagnostics.frame_lines);
    try std.testing.expect(result.diagnostics.max_line_cells <= 14);
    try std.testing.expect(result.diagnostics.clipped_sources >= 1);
    try std.testing.expect(std.mem.indexOf(u8, result.warning, "clipped") != null);
}

test "regular: file picker respects gitignore by default and opens selected file" {
    var client = try Client.init(std.testing.allocator, .{ .width = 40, .height = 6 });
    defer client.deinit();

    try client.handleTraceLine("repo_gitignore zig-out/");
    try client.handleTraceLine("repo_gitignore *.o");
    try client.handleTraceLine("repo_file src/main.zig=pubfnmain");
    try client.handleTraceLine("repo_file zig-out/bin/mim=binary");
    try client.handleTraceLine("repo_file build.o=object");
    try client.handleTraceLine("file_picker");
    {
        const frame = try client.render(std.testing.allocator);
        defer std.testing.allocator.free(frame);
        try std.testing.expect(std.mem.indexOf(u8, frame, "src/main.zig") != null);
        try std.testing.expect(std.mem.indexOf(u8, frame, "zig-out") == null);
        try std.testing.expect(std.mem.indexOf(u8, frame, "build.o") == null);
    }

    try client.handleTraceLine("file_open_selected");
    {
        const frame = try client.render(std.testing.allocator);
        defer std.testing.allocator.free(frame);
        try std.testing.expect(std.mem.indexOf(u8, frame, "pubfnmain") != null);
    }
}

test "regular: file picker include ignored toggle exposes ignored files" {
    var client = try Client.init(std.testing.allocator, .{ .width = 40, .height = 6 });
    defer client.deinit();

    try client.handleTraceLine("repo_gitignore zig-out/");
    try client.handleTraceLine("repo_file src/main.zig=main");
    try client.handleTraceLine("repo_file zig-out/bin/mim=binary");
    try client.handleTraceLine("file_picker all");
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "src/main.zig") != null);
    try std.testing.expect(std.mem.indexOf(u8, frame, "zig-out/bin/mim") != null);
}

test "regular: file tree uses the same panel primitive and include ignored boundary" {
    var client = try Client.init(std.testing.allocator, .{ .width = 40, .height = 6 });
    defer client.deinit();

    try client.handleTraceLine("repo_gitignore tmp/");
    try client.handleTraceLine("repo_file src/lib.zig=lib");
    try client.handleTraceLine("repo_file tmp/log.txt=log");
    try client.handleTraceLine("file_tree");
    {
        const frame = try client.render(std.testing.allocator);
        defer std.testing.allocator.free(frame);
        try std.testing.expect(std.mem.indexOf(u8, frame, "src/lib.zig") != null);
        try std.testing.expect(std.mem.indexOf(u8, frame, "tmp/log") == null);
    }

    try client.handleTraceLine("panel_close");
    try client.handleTraceLine("file_tree all");
    {
        const frame = try client.render(std.testing.allocator);
        defer std.testing.allocator.free(frame);
        try std.testing.expect(std.mem.indexOf(u8, frame, "tmp/log.txt") != null);
    }
}

test "adversarial: invalid repo paths and missing selections fail without corrupting editor" {
    var client = try Client.init(std.testing.allocator, .{ .width = 32, .height = 5 });
    defer client.deinit();

    try client.handleTraceLine("open safe");
    try std.testing.expectError(repo_mod.Error.InvalidPath, client.handleTraceLine("repo_file ../secret=x"));
    try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine("file_open_selected"));
    const frame = try client.render(std.testing.allocator);
    defer std.testing.allocator.free(frame);
    try std.testing.expect(std.mem.indexOf(u8, frame, "safe") != null);
}