# ============================================================================
# SCRIPT 40: Weekly Mosaic Creation (Per-Field CI Aggregation)
# ============================================================================
# PURPOSE:
#   Aggregate daily per-field CI TIFFs into weekly mosaics. Handles multi-date
#   merging, cloud masking, and produces 5-band weekly output for reporting
#   and KPI calculations. Supports both per-field and grid-based tile architecture.
#
# INPUT DATA:
#   - Source: laravel_app/storage/app/{project}/field_tiles_CI/{FIELD}/{DATE}.tif
#   - Format: GeoTIFF (5-band: R,G,B,NIR,CI as float32)
#   - Dates: All available dates within week range
#
# OUTPUT DATA:
#   - Destination: laravel_app/storage/app/{project}/weekly_mosaic/{FIELD}/
#   - Format: GeoTIFF (5-band: R,G,B,NIR,CI)
#   - Naming: week_WW_YYYY.tif (WW = ISO week, YYYY = ISO year)
#
# USAGE:
#   Rscript 40_mosaic_creation_per_field.R [end_date] [offset] [project]
#
#   Example (Windows PowerShell):
#   & "C:\Program Files\R\R-4.4.3\bin\x64\Rscript.exe" r_app/40_mosaic_creation_per_field.R 2026-01-12 7 angata
#
# PARAMETERS:
#   - end_date: End date for processing (character, YYYY-MM-DD format, default today)
#   - offset: Days to look back (numeric, default 7 for one week)
#   - project: Project name (character) - angata, chemba, xinavane, esa, simba
#
# CLIENT TYPES:
#   - cane_supply (ANGATA): Yes - weekly monitoring
#   - agronomic_support (AURA): Yes - field health reporting
#
# DEPENDENCIES:
#   - Packages: terra, sf, tidyverse, lubridate
#   - Utils files: parameters_project.R, 40_mosaic_creation_per_field_utils.R
#   - Input data: Daily per-field CI TIFFs from Script 20
#   - Data directories: field_tiles_CI/, weekly_mosaic/
#
# NOTES:
#   - Aggregation method: Maximum CI value per pixel across week (handles clouds)
#   - ISO week-year used for consistent date handling across year boundaries
#   - Supports both single-file and tiled mosaic architectures
#   - Output feeds Scripts 80 (KPI calculations) and 90/91 (reporting)
#   - Critical for trend analysis: week-over-week CI comparison
#
# RELATED ISSUES:
#   SC-112: Script 40 cleanup (deleted legacy mosaic utils files)
#   SC-108: Core pipeline improvements
#
# ============================================================================

# 1. Load required packages
# -----------------------
suppressPackageStartupMessages({
  library(sf)
  library(terra)
  library(tidyverse)
  library(lubridate)
  library(here)
})

# 2. Main execution function
# -------------------------
main <- function() {
  
  cat("\n")
  cat("========================================================\n")
  cat("  Script 40: Per-Field Weekly Mosaic Creation\n")
  cat("========================================================\n\n")
  
  # Capture command line arguments
  args <- commandArgs(trailingOnly = TRUE)
  
  # ==== Process Arguments ====
  
  # Project directory
  if (length(args) >= 3 && !is.na(args[3])) {
    project_dir <- as.character(args[3])
  } else if (exists("project_dir", envir = .GlobalEnv)) {
    project_dir <- get("project_dir", envir = .GlobalEnv)
  } else {
    project_dir <- "angata"
    message("[INFO] No project_dir provided. Using default: angata")
  }
  
  assign("project_dir", project_dir, envir = .GlobalEnv)
  message(paste("[INFO] Project:", project_dir))
  
  # End date
  if (length(args) >= 1 && !is.na(args[1])) {
    end_date <- as.Date(args[1], format = "%Y-%m-%d")
    if (is.na(end_date)) {
      message("[WARNING] Invalid end_date. Using current date.")
      end_date <- Sys.Date()
    }
  } else {
    end_date <- Sys.Date()
    message(paste("[INFO] No end_date provided. Using current date:", format(end_date)))
  }
  
  # Offset (days back)
  if (length(args) >= 2 && !is.na(args[2])) {
    offset <- as.numeric(args[2])
    if (is.na(offset) || offset <= 0) {
      message("[WARNING] Invalid offset. Using default: 7 days")
      offset <- 7
    }
  } else {
    offset <- 7
    message("[INFO] No offset provided. Using default: 7 days")
  }
  
  # ==== Load Configuration ====
  
  # Set working directory if needed
  if (basename(getwd()) == "r_app") {
    setwd("..")
  }
  
  tryCatch({
    source("r_app/parameters_project.R")
    message("[INFO] ✓ Loaded parameters_project.R")
  }, error = function(e) {
    stop("[ERROR] Failed to load parameters_project.R: ", e$message)
  })
  
  tryCatch({
    source("r_app/40_mosaic_creation_per_field_utils.R")
    message("[INFO] ✓ Loaded 40_mosaic_creation_per_field_utils.R")
  }, error = function(e) {
    stop("[ERROR] Failed to load utilities: ", e$message)
  })
  
  # ==== Get Project Directories ====
  
  setup <- setup_project_directories(project_dir)
  
  # Determine input/output directories
  # Input: field_tiles_CI/ (from Script 20)
  field_tiles_ci_dir <- setup$field_tiles_ci_dir
  
  # Output: weekly_mosaic/ (for Scripts 90/91)
  weekly_mosaic_output_dir <- file.path(setup$laravel_storage_dir, "weekly_mosaic")
  
  message(paste("[INFO] Input directory:", field_tiles_ci_dir))
  message(paste("[INFO] Output directory:", weekly_mosaic_output_dir))
  
  # ==== Validate Input Directory ====
  
  if (!dir.exists(field_tiles_ci_dir)) {
    stop(paste("[ERROR] Input directory not found:", field_tiles_ci_dir,
               "\nScript 20 (CI extraction) must be run first to create per-field TIFFs."))
  }
  
  # Check if directory has any TIFFs
  field_dirs <- list.dirs(field_tiles_ci_dir, full.names = FALSE, recursive = FALSE)
  if (length(field_dirs) == 0) {
    stop(paste("[ERROR] No field subdirectories found in:", field_tiles_ci_dir))
  }
  
  message(paste("[INFO] Found", length(field_dirs), "field directories"))
  
  # ==== Generate Date Range ====
  
  dates <- date_list(end_date, offset)
  
  # Validate week calculation
  message(sprintf("[INFO] Requested offset: %d days", offset))
  message(sprintf("[INFO] End date: %s", format(end_date, "%Y-%m-%d")))
  message(sprintf("[INFO] Start date: %s", format(dates$start_date, "%Y-%m-%d")))
  message(sprintf("[INFO] Calculating ISO week: %d", dates$week))
  message(sprintf("[INFO] Calculating ISO year: %d", dates$year))
  
  # ==== Create Per-Field Weekly Mosaics ====
  
  created_files <- create_all_field_weekly_mosaics(
    dates = dates,
    field_tiles_ci_dir = field_tiles_ci_dir,
    output_dir = weekly_mosaic_output_dir
  )
  
  # ==== Summary ====
  
  message("\n")
  message("========================================================")
  message(paste("  COMPLETED"))
  message(paste("  Created:", length(created_files), "weekly field mosaics"))
  message("========================================================\n")
  
  if (length(created_files) > 0) {
    message("[SUCCESS] Weekly mosaics ready for reporting (Scripts 90/91)")
  } else {
    message("[WARNING] No mosaics created - check input data")
  }
  
  return(invisible(created_files))
}

# Execute main if script is run directly
if (sys.nframe() == 0) {
  tryCatch({
    created <- main()
    quit(save = "no", status = 0)
  }, error = function(e) {
    message(paste("\n[FATAL ERROR]", e$message))
    quit(save = "no", status = 1)
  })
}