// All state management functions live here.
//
// These must match arle0.b implementation.

#ifndef STATE_H_
#define STATE_H_

#include<stdint.h>
#include<array>
#include<string>
#include<utility>
#include<vector>

constexpr int kWidth = 6;
constexpr int kHeight = 12;

// (top color, bottom color)
using Color = int8_t;
using Block = std::array<Color, 2>;

// Syntactic sugar for marking empty cells.
constexpr Color kEmpty = -1;

// List of blocks.
using BlockList = std::vector<Block>;

// List of columns.
using Grid = std::array<std::vector<Color>, kWidth>;

// List of (x, y) coordinates.
using Cluster = std::vector<std::pair<int, int>>;

// List of clusters.
using ClusterList = std::vector<Cluster>;

struct PendingBlock
{
   // Allowed movements.
   static constexpr char kLeft = 'h';
   static constexpr char kRight = 'l';
   static constexpr char kRotate = 'k';
   static constexpr char kDrop = 'j';

   explicit PendingBlock(const Block &c) : color(c) {}

   // Block state.
   int x = (kWidth - 1) / 2;
   int y = kHeight - 1;
   int orientation = 0;
   Block color;
};

// Access palette for a single tile
const char *GetTile(Color c);

// Print block list to stdout.
void DumpBlockList(const BlockList &block_list);

// Print grid state to stdout.
void DumpGrid(const Grid &grid);

// Generate list of blocks for a particular seed.
BlockList GenerateBlockList(int seed);

// Find all connected clusters in grid.
ClusterList MarkClusters(const Grid &grid);

// Apply a series of left/right/rotate movements to pending block.
// Drop block commands are ignored.
void ApplyMoves(const Grid &grid,
                const std::string &moves,
                PendingBlock *block);

// Drop block onto grid, apply chains, and return change in score.
int DropBlock(const PendingBlock &block, Grid *grid);

// Drop block onto grid, apply chains, and return changes after each
// chain.  If only one element is returned, it means dropping this
// block only scored the minimal one point for dropping it.
// Otherwise, each additional array element records the score after
// that many chains have been cleared.
std::vector<int> TraceDropBlock(const PendingBlock &block, Grid *grid);

#endif  // STATE_H_