#pragma once
// Character files (docs/characters.md): one file per character with its shared
// hero and one world per difficulty, plus reading the game's save files.

#include <array>
#include <cstdint>
#include <optional>
#include <string>
#include <vector>

#include <nlohmann/json.hpp>

namespace mods::characters {

using Bytes = std::vector<uint8_t>;

// Bronze, Silber, Gold, Platin, Niob (g_gameLevel 0..4).
constexpr int kDifficultyCount = 5;

// The campaigns (g_campaign 0x182cdc8): Ancaria 0, Underworld 1.
constexpr int kCampaignAncaria = 0;
constexpr int kCampaignUnderworld = 1;
constexpr int kCampaignCount = 2;

// What the game's save files (GAME.PAK "AMS", hero files .pax "AMH") say about
// their hero: header 0x100 bytes, then a table of 64 chunks {type, offset,
// size}; chunk 0xc3 is the hero header.
struct SaveInfo {
    std::wstring name;                 // hero header +8, UTF-16
    uint32_t heroClass = 0;            // hero header +4: 1 Seraphim .. 9 Daemonin
    uint32_t level = 0;                // hero header +0
    // Story completions per difficulty (hero header +0xed.., cStatsManager
    // +0x5704; the hero file's are the hero's, loadHero sets them).
    std::array<uint8_t, kDifficultyCount> storyCompleted{};
    bool world = false;                // a save game (AMS), not a hero file
    int difficulty = 0;                // AMS header +0x84 (g_gameLevel)
    int campaign = kCampaignAncaria;   // AMS header +0x24 (CampaignSaveMode)
    bool multiplayer = false;          // AMS header +0x2c
    uint64_t savedAt = 0;              // AMS header +0x5c SYSTEMTIME, as FILETIME
};
std::optional<SaveInfo> ReadSaveInfo(const Bytes& file);

// Writes `name` as the hero's name (hero header +8, 0x40 UTF-16 characters
// with the terminator), the only place the name is stored; false if the file
// has no hero header or the name is empty or too long.
constexpr size_t kHeroNameMaxChars = 63;
bool SetHeroName(Bytes& file, const std::wstring& name);

// Sets the hero header's story completions of `difficulty` (+0xed..; in a hero
// file they are the hero's, loadHero puts them into cStatsManager); false if
// the file has no hero header.
bool SetStoryCompleted(Bytes& file, int difficulty, uint8_t count);

// The save header's campaign field (+0x24): 2 Ancaria, 3 Underworld (written
// at 0x61a5c5, read back by cEngine::Load 0x61bafd).
uint32_t CampaignSaveMode(int campaign);

// A small save game the game's load window can list: `world`'s header with its
// date, its thumbnail and world time, and `description` (ANSI, up to 63
// characters) as the save's name. The load window lists only saves of the
// running campaign (0x71e2b9): the preview names `campaign`.
Bytes BuildPreview(const Bytes& world, const std::string& description, int campaign);

// Reading and writing whole files (paths in the game's code page).
std::optional<Bytes> ReadFile(const std::string& path);
bool WriteFileReplacing(const std::string& path, const Bytes& bytes);

// A character file: named sections ("meta" JSON, "hero" .pax, "world<d>"
// GAME.PAK). Sections are read from disk on demand; Save writes all of them
// to a temporary file and replaces the old one.
class CharacterFile {
public:
    explicit CharacterFile(std::string path) : path_(std::move(path)) {}

    // Reads the section table and the meta; false if the file is missing or
    // not a character file.
    bool Open();

    const std::string& Path() const { return path_; }
    bool Has(const std::string& section) const;
    std::optional<Bytes> Read(const std::string& section) const;
    void Set(const std::string& section, Bytes bytes);
    void Remove(const std::string& section);
    bool Save();

    nlohmann::json meta = nlohmann::json::object();

private:
    struct Section {
        std::string name;
        uint32_t offset = 0;  // in the file; unused once `data` is set
        uint32_t size = 0;
        std::optional<Bytes> data;  // set or changed since Open
    };
    std::string path_;
    std::vector<Section> sections_;
};

// A world's section: "ancaria<d>" / "underworld<d>", d = g_gameLevel. Sections
// are named, not slotted: more difficulties (or campaigns) are more sections.
std::string WorldSection(int campaign, int difficulty);

} // namespace mods::characters