#' Combined: Create master grid and split TIFFs into tiles
#' ====================================================================
#'
#' Purpose:
#' 1. Check all daily TIFFs for matching extents
#' 2. Create master 5×5 grid covering all TIFFs
#' 3. Split each daily TIFF into 25 tiles using the master grid
#' 4. Save tiles in date-specific folders: daily_tiles/[DATE]/[DATE]_[TILE_ID].tif

library(terra)
library(sf)

# ============================================================================
# CONFIGURATION
# ============================================================================

PROJECT <- "angata"
TIFF_FOLDER <- file.path("laravel_app", "storage", "app", PROJECT, "merged_tif_8b")
OUTPUT_FOLDER <- file.path("laravel_app", "storage", "app", PROJECT, "daily_tiles_split")

# Grid dimensions will be auto-determined based on ROI size
# Default: 5×5 = 25 tiles
# If ROI < 10×10 km: 1×1 = 1 tile (no splitting needed)
GRID_NROWS <- 5
GRID_NCOLS <- 5

cat("Combined: Create Master Grid (5x5) and Split TIFFs into Tiles\n")

# ============================================================================
# PART 1: CHECK TIFF EXTENTS AND CREATE MASTER GRID
# ============================================================================

cat("\n[PART 1] Creating Master Grid\n")

cat("\n[1] Checking TIFF extents...\n")

tiff_files <- list.files(TIFF_FOLDER, pattern = "\\.tif$", full.names = FALSE)
tiff_files <- sort(tiff_files)

if (length(tiff_files) == 0) {
  stop("No TIFF files found in ", TIFF_FOLDER)
}

cat("  Found", length(tiff_files), "TIFF file(s)\n")

# Load all extents
extents <- list()
for (i in seq_along(tiff_files)) {
  tiff_path <- file.path(TIFF_FOLDER, tiff_files[i])
  raster <- terra::rast(tiff_path)
  ext <- terra::ext(raster)
  extents[[i]] <- ext
}

# Check if all extents match
cat("\n[2] Comparing extents...\n")

tolerance <- 1e-8
all_match <- TRUE
first_ext <- extents[[1]]

for (i in 2:length(extents)) {
  curr_ext <- extents[[i]]
  match <- (
    abs(curr_ext$xmin - first_ext$xmin) < tolerance &&
    abs(curr_ext$xmax - first_ext$xmax) < tolerance &&
    abs(curr_ext$ymin - first_ext$ymin) < tolerance &&
    abs(curr_ext$ymax - first_ext$ymax) < tolerance
  )
  if (!match) {
    all_match <- FALSE
    cat("  ✗ Extent mismatch: ", tiff_files[1], " vs ", tiff_files[i], "\n", sep = "")
    cat("    File 1: X [", round(first_ext$xmin, 6), ", ", round(first_ext$xmax, 6), "] ", 
        "Y [", round(first_ext$ymin, 6), ", ", round(first_ext$ymax, 6), "]\n", sep = "")
    cat("    File ", i, ": X [", round(curr_ext$xmin, 6), ", ", round(curr_ext$xmax, 6), "] ",
        "Y [", round(curr_ext$ymin, 6), ", ", round(curr_ext$ymax, 6), "]\n", sep = "")
  }
}

if (all_match) {
  cat("  ✓ All TIFF extents MATCH perfectly!\n")
} else {
  cat("  ⚠️ Extents differ - creating master extent covering all\n")
}

# Create master extent
cat("\n[3] Creating master extent...\n")

master_xmin <- min(sapply(extents, function(e) e$xmin))
master_xmax <- max(sapply(extents, function(e) e$xmax))
master_ymin <- min(sapply(extents, function(e) e$ymin))
master_ymax <- max(sapply(extents, function(e) e$ymax))

x_range_m <- (master_xmax - master_xmin) * 111320
y_range_m <- (master_ymax - master_ymin) * 111320

cat("  Master extent: X [", round(master_xmin, 6), ", ", round(master_xmax, 6), "] ", 
    "Y [", round(master_ymin, 6), ", ", round(master_ymax, 6), "]\n", sep = "")
cat("  Coverage: ", round(x_range_m / 1000, 1), "km × ", round(y_range_m / 1000, 1), "km\n", sep = "")

# Auto-determine grid size based on ROI dimensions
if (x_range_m < 10000 && y_range_m < 10000) {
  cat("\n  ⚠️ ROI is small (< 10×10 km). Using single tile (1×1 grid) - no splitting needed!\n")
  GRID_NROWS <- 1
  GRID_NCOLS <- 1
} else {
  cat("\n  ROI size allows tiling. Using 5×5 grid (25 tiles per date).\n")
  GRID_NROWS <- 5
  GRID_NCOLS <- 5
}

N_TILES <- GRID_NROWS * GRID_NCOLS

# Check if master grid already exists
cat("\n[4] Checking if master grid exists...\n")

master_grid_file <- file.path(OUTPUT_FOLDER, "master_grid_5x5.geojson")

if (file.exists(master_grid_file)) {
  cat("  ✓ Master grid exists! Loading existing grid...\n")
  master_grid_sf <- st_read(master_grid_file, quiet = TRUE)
  master_grid_vect <- terra::vect(master_grid_file)
  cat("  ✓ Loaded grid with ", nrow(master_grid_sf), " tiles\n", sep = "")
} else {
  cat("  Grid does not exist. Creating new master grid...\n")
  
  # Create 5×5 grid
  cat("\n[5] Creating ", GRID_NCOLS, "×", GRID_NROWS, " master grid...\n", sep = "")
  
  master_bbox <- st_bbox(c(
    xmin = master_xmin,
    xmax = master_xmax,
    ymin = master_ymin,
    ymax = master_ymax
  ), crs = 4326)
  
  bbox_sf <- st_as_sfc(master_bbox)
  
  master_grid <- st_make_grid(
    bbox_sf,
    n = c(GRID_NCOLS, GRID_NROWS),
    what = "polygons"
  )
  
  master_grid_sf <- st_sf(
    tile_id = sprintf("%02d", 1:length(master_grid)),
    geometry = master_grid
  )
  
  cat("  ✓ Created grid with ", length(master_grid), " cells\n", sep = "")
  
  # Convert to SpatVector for use in makeTiles
  master_grid_vect <- terra::vect(master_grid_sf)
  
  # Save master grid
  if (!dir.exists(OUTPUT_FOLDER)) {
    dir.create(OUTPUT_FOLDER, recursive = TRUE, showWarnings = FALSE)
  }
  st_write(master_grid_sf, master_grid_file, delete_dsn = TRUE, quiet = TRUE)
  cat("  ✓ Master grid saved to: master_grid_5x5.geojson\n")
}

# ============================================================================
# PART 2: SPLIT EACH TIFF INTO TILES
# ============================================================================

cat("\n[PART 2] Splitting TIFFs into Tiles\n")

cat("\n[6] Splitting TIFFs using master grid...\n")

total_tiles_created <- 0

for (file_idx in seq_along(tiff_files)) {
  tiff_file <- tiff_files[file_idx]
  date_str <- gsub("\\.tif$", "", tiff_file)
  
  cat("\n  Processing: ", tiff_file, "\n", sep = "")
  
  # Load TIFF
  tiff_path <- file.path(TIFF_FOLDER, tiff_file)
  raster <- terra::rast(tiff_path)
  
  dims <- dim(raster)
  cat("    Dimensions: ", dims[2], "×", dims[1], " pixels\n", sep = "")
  
  # Create date-specific output folder
  date_output_folder <- file.path(OUTPUT_FOLDER, date_str)
  if (!dir.exists(date_output_folder)) {
    dir.create(date_output_folder, recursive = TRUE, showWarnings = FALSE)
  }
  
  cat("    Splitting into ", N_TILES, " tiles using master grid...\n", sep = "")
  
  # Split using master grid zones
  tiles_list <- terra::makeTiles(
    x = raster,
    y = master_grid_vect,
    filename = file.path(date_output_folder, "tile.tif"),
    overwrite = TRUE
  )
  
  cat("    ✓ Created ", length(tiles_list), " tiles\n", sep = "")
  
  # Rename tiles to [DATE]_[TILE_ID].tif
  cat("    Renaming tiles...\n")
  
  for (tile_idx in seq_along(tiles_list)) {
    source_file <- file.path(date_output_folder, paste0("tile", tile_idx, ".tif"))
    tile_id <- sprintf("%02d", tile_idx)
    final_file <- file.path(date_output_folder, paste0(date_str, "_", tile_id, ".tif"))
    
    if (file.exists(source_file)) {
      file.rename(source_file, final_file)
    }
  }
  
  cat("    ✓ Saved ", N_TILES, " tiles in folder: ", date_str, "/\n", sep = "")
  total_tiles_created <- total_tiles_created + length(tiles_list)
}

# ============================================================================
# VERIFICATION
# ============================================================================

cat("\n[7] Verifying output...\n")

# Count tiles per date folder
date_folders <- list.dirs(OUTPUT_FOLDER, full.names = FALSE, recursive = FALSE)
date_folders <- sort(date_folders[date_folders != "."])

total_tile_files <- 0
for (date_folder in date_folders) {
  tiles_in_folder <- list.files(file.path(OUTPUT_FOLDER, date_folder), 
                                pattern = "\\.tif$")
  tiles_in_folder <- tiles_in_folder[!grepl("master_grid", tiles_in_folder)]
  total_tile_files <- total_tile_files + length(tiles_in_folder)
  cat("  ", date_folder, ": ", length(tiles_in_folder), " tiles\n", sep = "")
}

# ============================================================================
# SUMMARY
# ============================================================================

cat("SUMMARY\n")

cat("\nMaster Grid:\n")
cat("  - Dimensions: ", GRID_NCOLS, "×", GRID_NROWS, "=", N_TILES, " tiles\n", sep = "")
cat("  - File: master_grid_5x5.geojson\n")

cat("\nTIFF Splitting:\n")
cat("  - TIFFs processed: ", length(tiff_files), "\n", sep = "")
cat("  - Total tile files created: ", total_tile_files, "\n", sep = "")
cat("  - Expected total: ", length(tiff_files) * N_TILES, "\n", sep = "")

cat("\nDirectory Structure:\n")
cat("  daily_tiles/\n")
cat("    ├── master_grid_5x5.geojson\n")
for (date_folder in date_folders) {
  cat("    ├── ", date_folder, "/\n", sep = "")
  cat("    │   ├── ", date_folder, "_01.tif\n", sep = "")
  cat("    │   ├── ", date_folder, "_02.tif\n", sep = "")
  cat("    │   └── ...\n")
}

cat("\nKey Properties:\n")
cat("  - All tiles align perfectly across dates\n")
cat("  - Tile 01 covers same area in all dates\n")
cat("  - Date folders provide organizational hierarchy\n")
cat("  - Can do time-series analysis per tile\n")

cat("✓ Script complete!\n")