## ----setup, include = FALSE---------------------------------------------------
knitr::opts_chunk$set(collapse = TRUE, comment = "#>")
library(regulog)

## ----genesis------------------------------------------------------------------
log <- regulog_init(app = "demo", version = "1.0", user = "analyst")

cat("Genesis hash:", log$genesis_hash, "\n")
cat("Last hash:   ", log$last_hash, "\n")

## ----first-entry--------------------------------------------------------------
log_action(
  log, "approved", "dataset_v1",
  "All quality checks passed — dataset approved for analysis"
)

entry <- log$entries[[1L]]
cat("Entry ID:   ", entry$entry_id, "\n")
cat("Prev hash:  ", entry$prev_hash, "\n") # = genesis hash
cat("Entry hash: ", entry$entry_hash, "\n")

## ----chain--------------------------------------------------------------------
log_action(log, "model_fit", "ANCOVA_v1", "Primary ANCOVA fitted per SAP")
log_note(log, "Outlier in subject 042 retained per SAP section 8.3")

cat("Entry 1 hash:", log$entries[[1L]]$entry_hash, "\n")
cat("Entry 2 prev:", log$entries[[2L]]$prev_hash, "\n")
cat("Match:       ", log$entries[[1L]]$entry_hash ==
  log$entries[[2L]]$prev_hash, "\n")

## ----verify-intact------------------------------------------------------------
verify_log(log)

## ----verify-result------------------------------------------------------------
result <- verify_log(log, verbose = FALSE)
str(result)

## ----tamper-content-----------------------------------------------------------
# Simulate a reason being altered
original_reason <- log$entries[[1L]]$reason
log$entries[[1L]]$reason <- "ALTERED"

result <- suppressWarnings(verify_log(log, verbose = FALSE))
cat("Intact:       ", result$intact, "\n")
cat("First broken: ", result$first_broken, "\n")
cat("Error:        ", result$errors[[1L]], "\n")

log$entries[[1L]]$reason <- original_reason # restore

## ----tamper-delete------------------------------------------------------------
saved <- log$entries
log$entries <- log$entries[-2L] # remove entry 2

result <- suppressWarnings(verify_log(log, verbose = FALSE))
cat("Intact:       ", result$intact, "\n")
cat("First broken: ", result$first_broken, "\n")

log$entries <- saved # restore

## ----tamper-hash--------------------------------------------------------------
saved_prev <- log$entries[[2L]]$prev_hash
log$entries[[2L]]$prev_hash <- paste(rep("0", 64L), collapse = "")

result <- suppressWarnings(verify_log(log, verbose = FALSE))
cat("Intact:       ", result$intact, "\n")
cat("First broken: ", result$first_broken, "\n")

log$entries[[2L]]$prev_hash <- saved_prev # restore
verify_log(log, verbose = FALSE)$intact # confirm restored

## ----verify-file, eval = FALSE------------------------------------------------
# # Can be run by a QC reviewer with no knowledge of the original session
# result <- verify_log("logs/trial001_audit.rlog")
# 
# # Structured result for programmatic use
# if (!result$intact) {
#   warning(sprintf(
#     "Log integrity failure: %d error(s). First broken entry: #%d",
#     length(result$errors), result$first_broken
#   ))
# }

## ----persistent, eval = FALSE-------------------------------------------------
# log <- regulog_init(
#   app     = "trial-analysis",
#   version = "1.0.0",
#   user    = "jsmith",
#   path    = "logs/trial001_audit.rlog"
# )
# 
# log_action(log, "data_read", "adsl.sas7bdat", "Reading ADSL")
# # ↑ This line is written to disk immediately
# 
# # The .rlog file at this point:
# # Line 1: {"entry_id":0,"type":"GENESIS",...}
# # Line 2: {"entry_id":1,"type":"ACTION","action":"data_read",...}

## ----archival, eval = FALSE---------------------------------------------------
# # Signed CSV — chain_intact and verified_at stamped on every row
# export_audit_trail(log,
#   format = "csv",
#   signed = TRUE,
#   path   = "archive/trial001_audit_2026-06-23.csv"
# )
# 
# # Original .rlog — keep this too; it allows re-verification later
# file.copy(
#   "logs/trial001_audit.rlog",
#   "archive/trial001_audit_2026-06-23.rlog"
# )