const std = @import("std");
const session_display_metadata = @import("session_display_metadata.zig");
const session_store = @import("session_store.zig");
const text_utils = @import("../shared/text_utils.zig");

pub const Scope = enum {
    current_workspace,
    all_workspaces,
};

pub const LoadState = enum {
    loading,
    ready,
    failed,
};

pub const ResumeFailure = enum {
    open_elsewhere,
    being_updated,
    unavailable,
};

pub fn filteredCount(summaries: []const session_store.SessionSummary, query: []const u8) usize {
    var count: usize = 0;
    for (summaries) |summary| {
        if (matchesQuery(summary, query)) count += 1;
    }
    return count;
}

pub fn summaryAt(
    summaries: []const session_store.SessionSummary,
    query: []const u8,
    display_index: usize,
) ?*const session_store.SessionSummary {
    var current: usize = 0;
    for (summaries) |*summary| {
        if (!matchesQuery(summary.*, query)) continue;
        if (current == display_index) return summary;
        current += 1;
    }
    return null;
}

pub fn displayTitle(summary: session_store.SessionSummary) []const u8 {
    return summary.title orelse session_display_metadata.fallback_title;
}

pub fn workspacePath(summary: session_store.SessionSummary) []const u8 {
    return summary.workspace_root orelse summary.origin_workspace_root orelse "(unknown workspace)";
}

pub fn relativeActivityAge(buf: []u8, updated_at_ms: i64, now_ms: i64) []const u8 {
    const delta_ms: i64 = @max(0, now_ms - updated_at_ms);
    if (delta_ms < std.time.ms_per_min) return "just now";
    if (delta_ms < std.time.ms_per_hour) {
        return std.fmt.bufPrint(buf, "{d}m ago", .{@divFloor(delta_ms, std.time.ms_per_min)}) catch "recently";
    }
    if (delta_ms < std.time.ms_per_day) {
        return std.fmt.bufPrint(buf, "{d}h ago", .{@divFloor(delta_ms, std.time.ms_per_hour)}) catch "recently";
    }
    return std.fmt.bufPrint(buf, "{d}d ago", .{@divFloor(delta_ms, std.time.ms_per_day)}) catch "recently";
}

// Same buckets as relativeActivityAge without the " ago" suffix, for tight
// single-line layouts: "now", "5m", "2h", "1d".
pub fn relativeActivityAgeCompact(buf: []u8, updated_at_ms: i64, now_ms: i64) []const u8 {
    const delta_ms: i64 = @max(0, now_ms - updated_at_ms);
    if (delta_ms < std.time.ms_per_min) return "now";
    if (delta_ms < std.time.ms_per_hour) {
        return std.fmt.bufPrint(buf, "{d}m", .{@divFloor(delta_ms, std.time.ms_per_min)}) catch "recently";
    }
    if (delta_ms < std.time.ms_per_day) {
        return std.fmt.bufPrint(buf, "{d}h", .{@divFloor(delta_ms, std.time.ms_per_hour)}) catch "recently";
    }
    return std.fmt.bufPrint(buf, "{d}d", .{@divFloor(delta_ms, std.time.ms_per_day)}) catch "recently";
}

fn matchesQuery(summary: session_store.SessionSummary, query: []const u8) bool {
    const query_text = std.mem.trim(u8, query, " \t\r\n");
    if (query_text.len == 0) return true;
    if (text_utils.containsIgnoreCase(displayTitle(summary), query_text)) return true;
    if (text_utils.containsIgnoreCase(workspacePath(summary), query_text)) return true;
    if (summary.preview) |preview| {
        if (text_utils.containsIgnoreCase(preview, query_text)) return true;
    }
    return false;
}

test "session catalog filters titles previews and workspace paths" {
    const summaries = [_]session_store.SessionSummary{
        .{
            .id = @constCast("one"),
            .workspace_root = @constCast("/worktrees/alpha"),
            .title = @constCast("Fix renderer"),
            .preview = @constCast("inspect footer state"),
            .created_at_ms = 1,
            .updated_at_ms = 2,
            .conversation_language = .literal("en"),
            .history_len = 4,
        },
        .{
            .id = @constCast("two"),
            .workspace_root = @constCast("/worktrees/beta"),
            .title = @constCast("Review sessions"),
            .created_at_ms = 1,
            .updated_at_ms = 3,
            .conversation_language = .literal("en"),
            .history_len = 2,
        },
    };

    try std.testing.expectEqual(@as(usize, 2), filteredCount(&summaries, ""));
    try std.testing.expectEqual(@as(usize, 1), filteredCount(&summaries, "RENDER"));
    try std.testing.expectEqualStrings("two", summaryAt(&summaries, "beta", 0).?.id);
    try std.testing.expectEqualStrings("one", summaryAt(&summaries, "footer", 0).?.id);
    try std.testing.expect(summaryAt(&summaries, "missing", 0) == null);
}

test "session catalog activity age uses the last update" {
    var buf: [32]u8 = undefined;
    try std.testing.expectEqualStrings("just now", relativeActivityAge(&buf, 1_000, 1_000));
    try std.testing.expectEqualStrings("3m ago", relativeActivityAge(&buf, 1_000, 1_000 + 3 * std.time.ms_per_min));
    try std.testing.expectEqualStrings("2h ago", relativeActivityAge(&buf, 1_000, 1_000 + 2 * std.time.ms_per_hour));
    try std.testing.expectEqualStrings("3d ago", relativeActivityAge(&buf, 1_000, 1_000 + 3 * std.time.ms_per_day));
}

test "session catalog compact activity age drops the ago suffix" {
    var buf: [32]u8 = undefined;
    try std.testing.expectEqualStrings("now", relativeActivityAgeCompact(&buf, 1_000, 1_000));
    try std.testing.expectEqualStrings("3m", relativeActivityAgeCompact(&buf, 1_000, 1_000 + 3 * std.time.ms_per_min));
    try std.testing.expectEqualStrings("2h", relativeActivityAgeCompact(&buf, 1_000, 1_000 + 2 * std.time.ms_per_hour));
    try std.testing.expectEqualStrings("3d", relativeActivityAgeCompact(&buf, 1_000, 1_000 + 3 * std.time.ms_per_day));
}