# ============================================================================
# SIMPLIFIED TWO-STAGE HARVEST ALERTS
# Based on stateful logic but adapted for daily operations
# ============================================================================
# STAGE 1: "Harvest will happen soon" (not "in exactly 14 days")
#   - Field was recently mature (CI > 3.5)
#   - CI dropped below 2.5 for 14+ consecutive days
#   - Alert: "Harvest expected soon - monitor this field"
#
# STAGE 2: "Harvest has occurred"  
#   - CI stabilized at very low level (< 2.0)
#   - Low variability for 5+ days (stable bare soil)
#   - Alert: "Harvest completed in recent days"
# ============================================================================

suppressPackageStartupMessages({
  library(readxl)
  library(dplyr)
  library(tidyr)
  library(lubridate)
  library(here)
  library(zoo)
})

project_dir <- "esa"
assign("project_dir", project_dir, envir = .GlobalEnv)

if (basename(getwd()) == "harvest_prediction") {
  setwd("../../..")
}

source(here("r_app", "parameters_project.R"))

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

CONFIG <- list(
  # STAGE 1: Harvest approaching
  mature_ci = 3.5,              # Field must have been mature (CI > this)
  harvest_ci = 2.5,             # Alert when below this
  consecutive_days = 14,        # Days below threshold to trigger
  lookback_mature = 60,         # Days to check for previous mature state
  min_field_age = 240,          # 8 months minimum
  
  # STAGE 2: Harvest completed  
  completed_ci = 2.0,           # Very low CI threshold
  stable_days = 5,              # Days of stable low CI
  max_variability = 0.3,        # Max SD for "stable"
  
  # Validation
  test_window_days = 21
)

cat("============================================================================\n")
cat("SIMPLIFIED HARVEST ALERT SYSTEM\n")
cat("============================================================================\n\n")

cat("STAGE 1 - HARVEST APPROACHING:\n")
cat("  - Field was mature (CI >", CONFIG$mature_ci, ") in last", CONFIG$lookback_mature, "days\n")
cat("  - CI drops below", CONFIG$harvest_ci, "for", CONFIG$consecutive_days, "consecutive days\n")
cat("  - Alert: 'Harvest expected soon - prepare logistics'\n\n")

cat("STAGE 2 - HARVEST COMPLETED:\n")
cat("  - CI below", CONFIG$completed_ci, "with low variability\n")
cat("  - Stable for", CONFIG$stable_days, "days\n")
cat("  - Alert: 'Harvest completed in recent days'\n\n")

# ============================================================================
# LOAD DATA
# ============================================================================

cat("=== LOADING DATA ===\n\n")

ci_rds_file <- here("laravel_app/storage/app", project_dir, "Data/extracted_ci/cumulative_vals/All_pivots_Cumulative_CI_quadrant_year_v2.rds")
ci_data_raw <- readRDS(ci_rds_file) %>% ungroup()

time_series_daily <- ci_data_raw %>%
  mutate(date = as.Date(Date)) %>%
  select(field_id = field, date, mean_ci = FitData) %>%
  filter(!is.na(mean_ci), !is.na(date), !is.na(field_id)) %>%
  arrange(field_id, date)

harvest_data <- read_excel('laravel_app/storage/app/esa/Data/harvest.xlsx') %>%
  mutate(
    season_start = as.Date(season_start),
    season_end = as.Date(season_end)
  ) %>%
  filter(!is.na(season_end))

fields_with_ci <- unique(time_series_daily$field_id)
harvest_data_filtered <- harvest_data %>%
  filter(field %in% fields_with_ci) %>%
  arrange(field, season_end)

cat("Fields:", length(fields_with_ci), "\n")
cat("Harvest events:", nrow(harvest_data_filtered), "\n\n")

# ============================================================================
# STAGE 1: HARVEST APPROACHING
# ============================================================================

detect_approaching <- function(field_ts, check_date, last_harvest_date, config = CONFIG) {
  # Check field age
  if (is.null(last_harvest_date) || is.na(last_harvest_date)) {
    earliest_date <- min(field_ts$date, na.rm = TRUE)
    field_age <- as.numeric(check_date - earliest_date)
  } else {
    field_age <- as.numeric(check_date - last_harvest_date)
  }
  
  if (field_age < config$min_field_age) {
    return(list(alert = FALSE, reason = "too_young", consecutive_days = 0))
  }
  
  # Check if field was recently mature
  recent_data <- field_ts %>%
    filter(date >= check_date - config$lookback_mature, date < check_date)
  
  was_mature <- any(recent_data$mean_ci > config$mature_ci, na.rm = TRUE)
  
  if (!was_mature) {
    return(list(alert = FALSE, reason = "never_mature", consecutive_days = 0))
  }
  
  # Count consecutive days below harvest threshold
  recent_ci <- field_ts %>%
    filter(date <= check_date, date >= check_date - 30) %>%
    arrange(desc(date))
  
  consecutive_days <- 0
  for (i in 1:nrow(recent_ci)) {
    if (!is.na(recent_ci$mean_ci[i]) && recent_ci$mean_ci[i] <= config$harvest_ci) {
      consecutive_days <- consecutive_days + 1
    } else {
      break
    }
  }
  
  alert <- consecutive_days >= config$consecutive_days
  
  return(list(
    alert = alert,
    reason = ifelse(alert, "APPROACHING", "not_sustained"),
    consecutive_days = consecutive_days
  ))
}

# ============================================================================
# STAGE 2: HARVEST COMPLETED
# ============================================================================

detect_completed <- function(field_ts, check_date, config = CONFIG) {
  # Get recent CI data
  recent_data <- field_ts %>%
    filter(date <= check_date, date >= check_date - config$stable_days) %>%
    arrange(date)
  
  if (nrow(recent_data) < config$stable_days) {
    return(list(alert = FALSE, reason = "insufficient_data"))
  }
  
  # Check if all recent days are below completed_ci threshold
  all_low <- all(recent_data$mean_ci <= config$completed_ci, na.rm = TRUE)
  
  if (!all_low) {
    return(list(alert = FALSE, reason = "not_low_enough"))
  }
  
  # Check variability (stable signal)
  ci_sd <- sd(recent_data$mean_ci, na.rm = TRUE)
  
  if (ci_sd > config$max_variability) {
    return(list(alert = FALSE, reason = "too_variable"))
  }
  
  return(list(
    alert = TRUE,
    reason = "COMPLETED",
    mean_ci = mean(recent_data$mean_ci, na.rm = TRUE),
    sd_ci = ci_sd
  ))
}

# ============================================================================
# VALIDATION
# ============================================================================

validate_simplified_system <- function(field_id) {
  field_ts <- time_series_daily %>%
    filter(field_id == !!field_id) %>%
    arrange(date)
  
  field_harvests <- harvest_data_filtered %>%
    filter(field == field_id) %>%
    arrange(season_end)
  
  if (nrow(field_harvests) == 0) return(NULL)
  
  all_results <- data.frame()
  
  for (h in 1:nrow(field_harvests)) {
    harvest_date <- field_harvests$season_end[h]
    last_harvest <- if (h == 1) NA else field_harvests$season_end[h - 1]
    
    test_dates_seq <- seq.Date(
      from = harvest_date - CONFIG$test_window_days,
      to = harvest_date + 14,
      by = "1 day"
    )
    
    for (i in 1:length(test_dates_seq)) {
      test_date <- test_dates_seq[i]
      days_from_harvest <- as.numeric(test_date - harvest_date)
      
      stage1 <- detect_approaching(field_ts, test_date, last_harvest, CONFIG)
      stage2 <- detect_completed(field_ts, test_date, CONFIG)
      
      all_results <- bind_rows(all_results, data.frame(
        field = field_id,
        harvest_event = h,
        harvest_date = harvest_date,
        test_date = test_date,
        days_from_harvest = days_from_harvest,
        stage1_alert = stage1$alert,
        stage1_reason = stage1$reason,
        stage2_alert = stage2$alert,
        stage2_reason = stage2$reason,
        consecutive_days = stage1$consecutive_days
      ))
    }
  }
  
  return(all_results)
}

# ============================================================================
# RUN VALIDATION
# ============================================================================

cat("============================================================================\n")
cat("VALIDATING ON FULL DATASET\n")
cat("============================================================================\n\n")

all_results <- data.frame()
summary_stats <- data.frame()

fields_to_test <- unique(harvest_data_filtered$field)
total_fields <- length(fields_to_test)

cat("Testing", total_fields, "fields...\n\n")
pb <- txtProgressBar(min = 0, max = total_fields, style = 3)

for (f in 1:total_fields) {
  field_id <- fields_to_test[f]
  
  field_results <- validate_simplified_system(field_id)
  
  if (!is.null(field_results) && nrow(field_results) > 0) {
    all_results <- bind_rows(all_results, field_results)
    
    field_harvests_count <- length(unique(field_results$harvest_event))
    
    # Stage 1: Any alert before harvest
    stage1_success <- field_results %>%
      filter(stage1_alert == TRUE, days_from_harvest < 0) %>%
      distinct(harvest_event) %>%
      nrow()
    
    # Stage 2: Detection within 1-7 days after
    stage2_success <- field_results %>%
      filter(stage2_alert == TRUE, days_from_harvest >= 1, days_from_harvest <= 7) %>%
      distinct(harvest_event) %>%
      nrow()
    
    summary_stats <- bind_rows(summary_stats, data.frame(
      field = field_id,
      total_harvests = field_harvests_count,
      stage1_success = stage1_success,
      stage2_success = stage2_success,
      stage1_rate = round(100 * stage1_success / field_harvests_count, 1),
      stage2_rate = round(100 * stage2_success / field_harvests_count, 1)
    ))
  }
  
  setTxtProgressBar(pb, f)
}

close(pb)

# ============================================================================
# RESULTS
# ============================================================================

cat("\n\n============================================================================\n")
cat("RESULTS BY FIELD\n")
cat("============================================================================\n\n")

print(summary_stats, row.names = FALSE)

cat("\n============================================================================\n")
cat("OVERALL PERFORMANCE\n")
cat("============================================================================\n\n")

total_harvests <- sum(summary_stats$total_harvests)
total_stage1 <- sum(summary_stats$stage1_success)
total_stage2 <- sum(summary_stats$stage2_success)

cat("Total harvest events:", total_harvests, "\n\n")

cat("STAGE 1 - HARVEST APPROACHING (any time before harvest):\n")
cat("  Success:", total_stage1, "/", total_harvests, 
    "(", round(100 * total_stage1 / total_harvests, 1), "% )\n")
cat("  Fields with >50% success:", sum(summary_stats$stage1_rate > 50), "/", total_fields, "\n\n")

cat("STAGE 2 - HARVEST COMPLETED (1-7 days after):\n")
cat("  Success:", total_stage2, "/", total_harvests,
    "(", round(100 * total_stage2 / total_harvests, 1), "% )\n")
cat("  Fields with >50% success:", sum(summary_stats$stage2_rate > 50), "/", total_fields, "\n\n")

cat("============================================================================\n")
cat("KEY INSIGHT\n")
cat("============================================================================\n\n")

cat("This approach doesn't predict 'harvest in X days' - it says:\n")
cat("  STAGE 1: 'Harvest will happen soon' (field mature → declining)\n")
cat("  STAGE 2: 'Harvest occurred recently' (bare soil detected)\n\n")

cat("No exact timing - just actionable binary alerts for factory planning\n\n")

# Save results
output_file <- here("r_app/experiments/harvest_prediction/simplified_validation_results.rds")
saveRDS(list(
  all_results = all_results,
  summary = summary_stats,
  config = CONFIG
), output_file)

cat("============================================================================\n")
cat("Results saved to:", output_file, "\n")
cat("============================================================================\n")