const std = @import("std");
const zid = @import("ZipponData");
const Allocator = std.mem.Allocator;
const Parser = @import("schemaParser.zig");
const Tokenizer = @import("tokenizers/schema.zig").Tokenizer;
const ZipponError = @import("errors.zig").ZipponError;
const dtype = @import("dtype");
const DataType = dtype.DataType;
const AdditionalData = @import("dataStructure/additionalData.zig");
const RelationMap = @import("dataStructure/relationMap.zig");
const JsonString = @import("dataStructure/relationMap.zig").JsonString;
const ConditionValue = @import("dataStructure/filter.zig").ConditionValue;
const UUID = dtype.UUID;
const UUIDFileIndex = @import("dataStructure/UUIDFileIndex.zig");
const FileEngine = @import("fileEngine.zig");

// TODO: Create a schemaEngine directory and add this as core and the parser with it

const config = @import("config");
const BUFFER_SIZE = config.BUFFER_SIZE;

var schema_buffer: [BUFFER_SIZE]u8 = undefined;

// TODO: Stop keeping the allocator at the root of the file
var arena: std.heap.ArenaAllocator = undefined;
var allocator: Allocator = undefined;

const log = std.log.scoped(.schemaEngine);

pub const SchemaStruct = struct {
    name: []const u8,
    members: [][]const u8,
    types: []DataType,
    zid_schema: []zid.DType,
    links: std.StringHashMap([]const u8), // Map key as member_name and value as struct_name of the link
    uuid_file_index: *UUIDFileIndex, // Map UUID to the index of the file store in

    pub fn init(
        name: []const u8,
        members: [][]const u8,
        types: []DataType,
        links: std.StringHashMap([]const u8),
    ) ZipponError!SchemaStruct {
        const uuid_file_index = allocator.create(UUIDFileIndex) catch return ZipponError.MemoryError;
        uuid_file_index.* = UUIDFileIndex.init(allocator) catch return ZipponError.MemoryError;
        return SchemaStruct{
            .name = name,
            .members = members,
            .types = types,
            .zid_schema = SchemaStruct.fileDataSchema(types) catch return ZipponError.MemoryError,
            .links = links,
            .uuid_file_index = uuid_file_index,
        };
    }

    fn fileDataSchema(dtypes: []DataType) ZipponError![]zid.DType {
        var schema = std.ArrayList(zid.DType).init(allocator);

        for (dtypes) |dt| {
            schema.append(switch (dt) {
                .int => .Int,
                .float => .Float,
                .str => .Str,
                .bool => .Bool,
                .link => .UUID,
                .self => .UUID,
                .date => .Unix,
                .time => .Unix,
                .datetime => .Unix,
                .int_array => .IntArray,
                .float_array => .FloatArray,
                .str_array => .StrArray,
                .bool_array => .BoolArray,
                .date_array => .UnixArray,
                .time_array => .UnixArray,
                .datetime_array => .UnixArray,
                .link_array => .UUIDArray,
            }) catch return ZipponError.MemoryError;
        }
        return schema.toOwnedSlice() catch return ZipponError.MemoryError;
    }
};

/// Manage everything that is relate to the schema
/// This include keeping in memory the schema and schema file, and some functions to get like all members of a specific struct.
/// For now it is a bit empty. But this is where I will manage migration
pub const SchemaEngine = @This();

struct_array: []SchemaStruct,
null_terminated: [:0]u8,

// The path is the path to the schema file
pub fn init(path: []const u8, file_engine: *FileEngine) ZipponError!SchemaEngine {
    arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
    allocator = arena.allocator();

    var buffer: [BUFFER_SIZE]u8 = undefined;

    log.debug("Trying to init a SchemaEngine with path {s}", .{path});
    const len: usize = try FileEngine.readSchemaFile(path, &buffer);
    const null_terminated = std.fmt.bufPrintZ(&schema_buffer, "{s}", .{buffer[0..len]}) catch return ZipponError.MemoryError;

    var toker = Tokenizer.init(null_terminated);
    var parser = Parser.init(&toker, allocator);

    var struct_array = std.ArrayList(SchemaStruct).init(allocator);
    errdefer struct_array.deinit();
    parser.parse(&struct_array) catch return ZipponError.SchemaNotConform;

    log.debug("SchemaEngine init with {d} SchemaStruct.", .{struct_array.items.len});

    for (struct_array.items) |sstruct| {
        file_engine.populateFileIndexUUIDMap(sstruct, sstruct.uuid_file_index) catch |err| {
            log.err("Error populate file index UUID map {any}", .{err});
        };
    }

    return SchemaEngine{
        .struct_array = struct_array.toOwnedSlice() catch return ZipponError.MemoryError,
        .null_terminated = null_terminated,
    };
}

pub fn deinit(_: SchemaEngine) void {
    arena.deinit();
}

/// Get the type of the member
pub fn memberName2DataType(self: *SchemaEngine, struct_name: []const u8, member_name: []const u8) ZipponError!DataType {
    for (try self.structName2structMembers(struct_name), 0..) |mn, i| {
        const dtypes = try self.structName2DataType(struct_name);
        if (std.mem.eql(u8, mn, member_name)) return dtypes[i];
    }

    return ZipponError.MemberNotFound;
}

pub fn memberName2DataIndex(self: *SchemaEngine, struct_name: []const u8, member_name: []const u8) ZipponError!usize {
    for (try self.structName2structMembers(struct_name), 0..) |mn, i| {
        if (std.mem.eql(u8, mn, member_name)) return i;
    }

    return ZipponError.MemberNotFound;
}

/// Get the list of all member name for a struct name
pub fn structName2structMembers(self: SchemaEngine, struct_name: []const u8) ZipponError![][]const u8 {
    var i: usize = 0;

    while (i < self.struct_array.len) : (i += 1) if (std.mem.eql(u8, self.struct_array[i].name, struct_name)) break;

    if (i == self.struct_array.len) {
        return ZipponError.StructNotFound;
    }

    return self.struct_array[i].members;
}

pub fn structName2SchemaStruct(self: SchemaEngine, struct_name: []const u8) ZipponError!SchemaStruct {
    var i: usize = 0;

    while (i < self.struct_array.len) : (i += 1) if (std.mem.eql(u8, self.struct_array[i].name, struct_name)) break;

    if (i == self.struct_array.len) {
        return ZipponError.StructNotFound;
    }

    return self.struct_array[i];
}

pub fn structName2DataType(self: SchemaEngine, struct_name: []const u8) ZipponError![]const DataType {
    var i: u16 = 0;

    while (i < self.struct_array.len) : (i += 1) {
        if (std.mem.eql(u8, self.struct_array[i].name, struct_name)) break;
    }

    if (i == self.struct_array.len and !std.mem.eql(u8, self.struct_array[i].name, struct_name)) {
        return ZipponError.StructNotFound;
    }

    return self.struct_array[i].types;
}

/// Chech if the name of a struct is in the current schema
pub fn isStructNameExists(self: SchemaEngine, struct_name: []const u8) bool {
    var i: u16 = 0;
    while (i < self.struct_array.len) : (i += 1) if (std.mem.eql(u8, self.struct_array[i].name, struct_name)) return true;
    return false;
}

/// Check if a struct have the member name
pub fn isMemberNameInStruct(self: SchemaEngine, struct_name: []const u8, member_name: []const u8) ZipponError!bool {
    for (try self.structName2structMembers(struct_name)) |mn| {
        if (std.mem.eql(u8, mn, member_name)) return true;
    }
    return false;
}

/// Return the SchemaStruct of the struct that the member is linked. So if it is not a link, it is itself, if it is a link, it the the sstruct of the link
pub fn linkedStructName(self: SchemaEngine, struct_name: []const u8, member_name: []const u8) ZipponError!SchemaStruct {
    const sstruct = try self.structName2SchemaStruct(struct_name);
    if (sstruct.links.get(member_name)) |struct_link_name| {
        return try self.structName2SchemaStruct(struct_link_name);
    }
    return sstruct;
}

// Return true if the map have all the member name as key and not more
pub fn checkIfAllMemberInMap(
    self: SchemaEngine,
    struct_name: []const u8,
    map: *std.StringHashMap(ConditionValue),
    error_message_buffer: *std.ArrayList(u8),
) ZipponError!bool {
    const all_struct_member = try self.structName2structMembers(struct_name);
    var count: u16 = 0;

    const writer = error_message_buffer.writer();

    for (all_struct_member) |mn| {
        if (std.mem.eql(u8, mn, "id")) continue;
        if (map.contains(mn)) count += 1 else writer.print(" {s},", .{mn}) catch return ZipponError.WriteError;
    }

    return ((count == all_struct_member.len - 1) and (count == map.count()));
}

pub fn isUUIDExist(self: SchemaEngine, struct_name: []const u8, uuid: UUID) bool {
    const sstruct = self.structName2SchemaStruct(struct_name) catch return false;
    return sstruct.uuid_file_index.contains(uuid);
}

/// Create an array of empty RelationMap based on the additionalData
pub fn relationMapArrayInit(
    self: SchemaEngine,
    alloc: Allocator,
    struct_name: []const u8,
    additional_data: AdditionalData,
) ZipponError![]RelationMap {
    // So here I should have relationship if children are relations
    var array = std.ArrayList(RelationMap).init(alloc);
    const sstruct = try self.structName2SchemaStruct(struct_name);
    for (additional_data.childrens.items) |child| if (sstruct.links.contains(child.name)) {
        const map = alloc.create(std.AutoHashMap([16]u8, JsonString)) catch return ZipponError.MemoryError;
        map.* = std.AutoHashMap([16]u8, JsonString).init(alloc);
        array.append(RelationMap{
            .struct_name = sstruct.links.get(child.name).?,
            .member_name = child.name,
            .additional_data = child.additional_data, // Maybe I need to check if it exist, im not sure it always exist
            .map = map,
        }) catch return ZipponError.MemoryError;
    };
    return array.toOwnedSlice() catch return ZipponError.MemoryError;
}

pub fn fileListToParse(
    self: SchemaEngine,
    alloc: Allocator,
    struct_name: []const u8,
    map: std.AutoHashMap([16]u8, JsonString),
) ZipponError![]usize {
    const sstruct = try self.structName2SchemaStruct(struct_name);
    var unique_indices = std.AutoHashMap(usize, void).init(alloc);
    defer unique_indices.deinit();

    var iter = map.keyIterator();
    while (iter.next()) |uuid| {
        if (sstruct.uuid_file_index.get(UUID{ .bytes = uuid.* })) |file_index| {
            unique_indices.put(file_index, {}) catch return ZipponError.MemoryError;
        }
    }

    var result = alloc.alloc(usize, unique_indices.count()) catch return ZipponError.MemoryError;
    var i: usize = 0;
    var index_iter = unique_indices.keyIterator();
    while (index_iter.next()) |index| {
        result[i] = index.*;
        i += 1;
    }

    return result;
}